[llvm] [llubi] Experimental support for noalias (PR #195808)
Zhige Chen via llvm-commits
llvm-commits at lists.llvm.org
Sat Sep 26 02:58:16 PDT 2026
https://github.com/nofe1248 updated https://github.com/llvm/llvm-project/pull/195808
>From e5ddf0abc73ab68d060f0b61c4b38e26452f68bd Mon Sep 17 00:00:00 2001
From: Zhige Chen <zhigec_cpp at outlook.com>
Date: Tue, 5 May 2026 16:21:12 +0800
Subject: [PATCH 1/5] [llubi] Experimental noalias support
---
llvm/test/tools/llubi/noalias_after_return.ll | 35 ++
.../tools/llubi/noalias_aliasing_reads.ll | 46 ++
.../llubi/noalias_disabled_by_default.ll | 29 ++
.../tools/llubi/noalias_disjoint_intervals.ll | 49 ++
.../tools/llubi/noalias_foreign_access.ll | 32 ++
.../test/tools/llubi/noalias_outside_range.ll | 56 ++
.../tools/llubi/noalias_overlapping_ranges.ll | 46 ++
.../tools/llubi/noalias_prune_stale_node.ll | 51 ++
.../llubi/noalias_reserved_foreign_read.ll | 35 ++
llvm/tools/llubi/lib/Context.cpp | 482 +++++++++++++++++-
llvm/tools/llubi/lib/Context.h | 102 ++++
llvm/tools/llubi/lib/ExecutorBase.cpp | 51 +-
llvm/tools/llubi/lib/ExecutorBase.h | 9 +-
llvm/tools/llubi/lib/Interpreter.cpp | 16 +-
llvm/tools/llubi/lib/Value.h | 67 ++-
llvm/tools/llubi/llubi.cpp | 10 +
16 files changed, 1086 insertions(+), 30 deletions(-)
create mode 100644 llvm/test/tools/llubi/noalias_after_return.ll
create mode 100644 llvm/test/tools/llubi/noalias_aliasing_reads.ll
create mode 100644 llvm/test/tools/llubi/noalias_disabled_by_default.ll
create mode 100644 llvm/test/tools/llubi/noalias_disjoint_intervals.ll
create mode 100644 llvm/test/tools/llubi/noalias_foreign_access.ll
create mode 100644 llvm/test/tools/llubi/noalias_outside_range.ll
create mode 100644 llvm/test/tools/llubi/noalias_overlapping_ranges.ll
create mode 100644 llvm/test/tools/llubi/noalias_prune_stale_node.ll
create mode 100644 llvm/test/tools/llubi/noalias_reserved_foreign_read.ll
diff --git a/llvm/test/tools/llubi/noalias_after_return.ll b/llvm/test/tools/llubi/noalias_after_return.ll
new file mode 100644
index 00000000000000..6738a951b53c6f
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_after_return.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @write_one(ptr noalias %x) {
+ store i32 1, ptr %x
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @write_one(ptr %a)
+ %v = load i32, ptr %a
+ store i32 2, ptr %a
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: write_one
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'a' bytes [0, 4): Reserved -> Unique
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: protector end for node #1 triggers synthetic write on 'a' bytes [0, 4)
+; CHECK-NEXT: NoAlias: protector end: node #1 local write through node #1 on 'a' bytes [0, 4): Unique -> Unique
+; CHECK-NEXT: NoAlias: ended protector node #1
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: Exiting function: write_one
+; CHECK-NEXT: call void @write_one(ptr %a)
+; CHECK-NEXT: %v = load i32, ptr %a, align 4 => i32 1
+; CHECK-NEXT: store i32 2, ptr %a, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_aliasing_reads.ll b/llvm/test/tools/llubi/noalias_aliasing_reads.ll
new file mode 100644
index 00000000000000..c1fcd813c0211c
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_aliasing_reads.ll
@@ -0,0 +1,46 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @read_both(ptr noalias %x, ptr noalias %y) {
+ %vx = load i32, ptr %x
+ %vy = load i32, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 42, ptr %a
+ call void @read_both(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: store i32 42, ptr %a, align 4
+; CHECK-NEXT: Entering function: read_both
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %y = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: node #1 local read through node #1 on 'a' bytes [0, 4): Reserved -> ReservedL
+; CHECK-NEXT: NoAlias: node #2 foreign read through node #1 on 'a' bytes [0, 4): Reserved -> ReservedF
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 2 active noalias protectors
+; CHECK-NEXT: %vx = load i32, ptr %x, align 4 => i32 42
+; CHECK-NEXT: NoAlias: node #1 foreign read through node #2 on 'a' bytes [0, 4): ReservedL -> ReservedLF
+; CHECK-NEXT: NoAlias: node #2 local read through node #2 on 'a' bytes [0, 4): ReservedF -> ReservedLF
+; CHECK-NEXT: NoAlias: read through node #2 on 'a' bytes [0, 4) checked 2 active noalias protectors
+; CHECK-NEXT: %vy = load i32, ptr %y, align 4 => i32 42
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: protector end for node #1 triggers synthetic read on 'a' bytes [0, 4)
+; CHECK-NEXT: NoAlias: protector end: node #1 local read through node #1 on 'a' bytes [0, 4): ReservedLF -> ReservedLF
+; CHECK-NEXT: NoAlias: protector end: node #2 foreign read through node #1 on 'a' bytes [0, 4): ReservedLF -> ReservedLF
+; CHECK-NEXT: NoAlias: ended protector node #1
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: NoAlias: protector end for node #2 triggers synthetic read on 'a' bytes [0, 4)
+; CHECK-NEXT: NoAlias: protector end: node #2 local read through node #2 on 'a' bytes [0, 4): ReservedLF -> ReservedLF
+; CHECK-NEXT: NoAlias: ended protector node #2
+; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: Exiting function: read_both
+; CHECK-NEXT: call void @read_both(ptr %a, ptr %a)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_disabled_by_default.ll b/llvm/test/tools/llubi/noalias_disabled_by_default.ll
new file mode 100644
index 00000000000000..65ce89ac44636c
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_disabled_by_default.ll
@@ -0,0 +1,29 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --verbose < %s 2>&1 | FileCheck %s
+
+define void @violates_if_enabled(ptr noalias %x, ptr %y) {
+ store i32 1, ptr %x
+ %v = load i32, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ call void @violates_if_enabled(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: Entering function: violates_if_enabled
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %y = ptr 0x8 [a]
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: %v = load i32, ptr %y, align 4 => i32 1
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: violates_if_enabled
+; CHECK-NEXT: call void @violates_if_enabled(ptr %a, ptr %a)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_disjoint_intervals.ll b/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
new file mode 100644
index 00000000000000..dd9030e9ea10f6
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
@@ -0,0 +1,49 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @write_disjoint(ptr noalias %x, ptr noalias %y) {
+ store i32 1, ptr %x
+ store i32 2, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca [2 x i32]
+ %x = getelementptr [2 x i32], ptr %a, i64 0, i64 0
+ %y = getelementptr [2 x i32], ptr %a, i64 0, i64 1
+ call void @write_disjoint(ptr %x, ptr %y)
+ %v = load [2 x i32], ptr %a
+ ret void
+}
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca [2 x i32], align 4 => ptr 0x8 [a]
+; CHECK-NEXT: %x = getelementptr [2 x i32], ptr %a, i64 0, i64 0 => ptr 0x8 [a]
+; CHECK-NEXT: %y = getelementptr [2 x i32], ptr %a, i64 0, i64 1 => ptr 0xC [a + 4]
+; CHECK-NEXT: Entering function: write_disjoint
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %y = ptr 0xC [a + 4]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'a' bytes [0, 4): Reserved -> Unique
+; CHECK-NEXT: NoAlias: node #2 foreign write through node #1 on 'a' bytes [0, 4): Reserved -> Disabled
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 2 active noalias protectors
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: NoAlias: node #1 foreign write through node #2 on 'a' bytes [4, 8): Reserved -> Disabled
+; CHECK-NEXT: NoAlias: node #2 local write through node #2 on 'a' bytes [4, 8): Reserved -> Unique
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [4, 8) checked 2 active noalias protectors
+; CHECK-NEXT: store i32 2, ptr %y, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: protector end for node #1 triggers synthetic write on 'a' bytes [0, 4)
+; CHECK-NEXT: NoAlias: protector end: node #1 local write through node #1 on 'a' bytes [0, 4): Unique -> Unique
+; CHECK-NEXT: NoAlias: protector end: node #2 foreign write through node #1 on 'a' bytes [0, 4): Disabled -> Disabled
+; CHECK-NEXT: NoAlias: ended protector node #1
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: NoAlias: protector end for node #2 triggers synthetic write on 'a' bytes [4, 8)
+; CHECK-NEXT: NoAlias: protector end: node #2 local write through node #2 on 'a' bytes [4, 8): Unique -> Unique
+; CHECK-NEXT: NoAlias: ended protector node #2
+; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: Exiting function: write_disjoint
+; CHECK-NEXT: call void @write_disjoint(ptr %x, ptr %y)
+; CHECK-NEXT: %v = load [2 x i32], ptr %a, align 4 => { i32 1, i32 2 }
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_foreign_access.ll b/llvm/test/tools/llubi/noalias_foreign_access.ll
new file mode 100644
index 00000000000000..b76effb09d746c
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_foreign_access.ll
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @violates(ptr noalias %x, ptr %y) {
+ store i32 1, ptr %x
+ %v = load i32, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ call void @violates(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: Entering function: violates
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %y = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'a' bytes [0, 4): Reserved -> Unique
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i32, ptr %y, align 4 at @violates
+; CHECK-NEXT: #1 call void @violates(ptr %a, ptr %a) at @main
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_outside_range.ll b/llvm/test/tools/llubi/noalias_outside_range.ll
new file mode 100644
index 00000000000000..aa946d0f11e84a
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_outside_range.ll
@@ -0,0 +1,56 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; Ported from Miri's tests/fail/tree_borrows/outside-range.rs:
+; protector checks are byte-range precise. Foreign writes outside the bytes
+; previously used by the protected pointer do not fail, but invalidating an
+; accessed byte does.
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @stuff(ptr noalias %x, ptr %raw) {
+ %raw1 = getelementptr i8, ptr %raw, i64 1
+ store i8 42, ptr %raw1
+ %x2 = getelementptr i8, ptr %x, i64 2
+ %v2 = load i8, ptr %x2
+ %x3 = getelementptr i8, ptr %x, i64 3
+ %v3 = load i8, ptr %x3
+ %raw3 = getelementptr i8, ptr %raw, i64 3
+ store i8 42, ptr %raw3
+ ret void
+}
+
+define void @main() {
+ %data = alloca [4 x i8]
+ %raw = getelementptr [4 x i8], ptr %data, i64 0, i64 0
+ call void @stuff(ptr %raw, ptr %raw)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %data = alloca [4 x i8], align 1 => ptr 0x8 [data]
+; CHECK-NEXT: %raw = getelementptr [4 x i8], ptr %data, i64 0, i64 0 => ptr 0x8 [data]
+; CHECK-NEXT: Entering function: stuff
+; CHECK-NEXT: ptr %x = ptr 0x8 [data]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [data]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'data' based on raw/root
+; CHECK-NEXT: %raw1 = getelementptr i8, ptr %raw, i64 1 => ptr 0x9 [data + 1]
+; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'data' bytes [1, 2): Reserved -> Disabled
+; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [1, 2) checked 1 active noalias protector
+; CHECK-NEXT: store i8 42, ptr %raw1, align 1
+; CHECK-NEXT: %x2 = getelementptr i8, ptr %x, i64 2 => ptr 0xA [data + 2]
+; CHECK-NEXT: NoAlias: node #1 foreign read through raw/root on 'data' bytes [2, 3): Reserved -> ReservedF
+; CHECK-NEXT: NoAlias: read through raw/root on 'data' bytes [2, 3) checked 1 active noalias protector
+; CHECK-NEXT: %v2 = load i8, ptr %x2, align 1 => i8 62
+; CHECK-NEXT: %x3 = getelementptr i8, ptr %x, i64 3 => ptr 0xB [data + 3]
+; CHECK-NEXT: NoAlias: node #1 foreign read through raw/root on 'data' bytes [3, 4): Reserved -> ReservedF
+; CHECK-NEXT: NoAlias: read through raw/root on 'data' bytes [3, 4) checked 1 active noalias protector
+; CHECK-NEXT: %v3 = load i8, ptr %x3, align 1 => i8 -117
+; CHECK-NEXT: %raw3 = getelementptr i8, ptr %raw, i64 3 => ptr 0xB [data + 3]
+; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'data' bytes [3, 4): ReservedF -> Disabled
+; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [3, 4) checked 1 active noalias protector
+; CHECK-NEXT: store i8 42, ptr %raw3, align 1
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended protector node #1
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: Exiting function: stuff
+; CHECK-NEXT: call void @stuff(ptr %raw, ptr %raw)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_overlapping_ranges.ll b/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
new file mode 100644
index 00000000000000..068e4a9136ee90
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
@@ -0,0 +1,46 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; Ported from Miri's tests/fail/both_borrows/buggy_split_at_mut.rs:
+; two supposedly independent mutable ranges overlap, so writes through both
+; protected noalias arguments are rejected.
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @write_overlap(ptr noalias %a, ptr noalias %b) {
+ %a1 = getelementptr [4 x i32], ptr %a, i64 0, i64 1
+ store i32 5, ptr %a1
+ %b1 = getelementptr [4 x i32], ptr %b, i64 0, i64 1
+ store i32 6, ptr %b1
+ ret void
+}
+
+define void @main() {
+ %array = alloca [4 x i32]
+ call void @write_overlap(ptr %array, ptr %array)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %array = alloca [4 x i32], align 4 => ptr 0x8 [array]
+; CHECK-NEXT: Entering function: write_overlap
+; CHECK-NEXT: ptr %a = ptr 0x8 [array]
+; CHECK-NEXT: ptr %b = ptr 0x8 [array]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'array' based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'array' based on raw/root
+; CHECK-NEXT: %a1 = getelementptr [4 x i32], ptr %a, i64 0, i64 1 => ptr 0xC [array + 4]
+; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'array' bytes [4, 8): Reserved -> Disabled
+; CHECK-NEXT: NoAlias: node #2 foreign write through raw/root on 'array' bytes [4, 8): Reserved -> Disabled
+; CHECK-NEXT: NoAlias: write through raw/root on 'array' bytes [4, 8) checked 2 active noalias protectors
+; CHECK-NEXT: store i32 5, ptr %a1, align 4
+; CHECK-NEXT: %b1 = getelementptr [4 x i32], ptr %b, i64 0, i64 1 => ptr 0xC [array + 4]
+; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'array' bytes [4, 8): Disabled -> Disabled
+; CHECK-NEXT: NoAlias: node #2 foreign write through raw/root on 'array' bytes [4, 8): Disabled -> Disabled
+; CHECK-NEXT: NoAlias: write through raw/root on 'array' bytes [4, 8) checked 2 active noalias protectors
+; CHECK-NEXT: store i32 6, ptr %b1, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended protector node #1
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: NoAlias: ended protector node #2
+; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: Exiting function: write_overlap
+; CHECK-NEXT: call void @write_overlap(ptr %array, ptr %array)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_prune_stale_node.ll b/llvm/test/tools/llubi/noalias_prune_stale_node.ll
new file mode 100644
index 00000000000000..da83ef7d01659f
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_prune_stale_node.ll
@@ -0,0 +1,51 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @capture(ptr noalias %x, ptr %slot) {
+ store ptr %x, ptr %slot
+ ret void
+}
+
+define void @write_one(ptr noalias %x) {
+ store i32 1, ptr %x
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ %slot = alloca ptr
+ call void @capture(ptr %a, ptr %slot)
+ %stale = load ptr, ptr %slot
+ call void @write_one(ptr %stale)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: %slot = alloca ptr, align 8 => ptr 0x10 [slot]
+; CHECK-NEXT: Entering function: capture
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %slot = ptr 0x10 [slot]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: store ptr %x, ptr %slot, align 8
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended protector node #1
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: Exiting function: capture
+; CHECK-NEXT: call void @capture(ptr %a, ptr %slot)
+; CHECK-NEXT: %stale = load ptr, ptr %slot, align 8 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: write_one
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: node #2 local write through node #2 on 'a' bytes [0, 4): Reserved -> Unique
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: protector end for node #2 triggers synthetic write on 'a' bytes [0, 4)
+; CHECK-NEXT: NoAlias: protector end: node #2 local write through node #2 on 'a' bytes [0, 4): Unique -> Unique
+; CHECK-NEXT: NoAlias: ended protector node #2
+; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: Exiting function: write_one
+; CHECK-NEXT: call void @write_one(ptr %stale)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll b/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll
new file mode 100644
index 00000000000000..671659b1759f79
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; Adapted from Miri's tests/pass/tree_borrows/reserved.rs int_protected_read:
+; a protected Reserved pointer can observe a foreign read, but a later local
+; write is then forbidden.
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @foreign_read_then_local_write(ptr noalias %x, ptr %raw) {
+ %v = load i32, ptr %raw
+ store i32 1, ptr %x
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ call void @foreign_read_then_local_write(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: Entering function: foreign_read_then_local_write
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: node #1 foreign read through raw/root on 'a' bytes [0, 4): Reserved -> ReservedF
+; CHECK-NEXT: NoAlias: read through raw/root on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: %v = load i32, ptr %raw, align 4 => i32 0
+; CHECK-NEXT: NoAlias: noalias violation: write through node #1 on 'a' bytes [0, 4) is local to protected node #1, but that protector is in ReservedF state
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i32 1, ptr %x, align 4 at @foreign_read_then_local_write
+; CHECK-NEXT: #1 call void @foreign_read_then_local_write(ptr %a, ptr %a) at @main
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #1 on 'a' bytes [0, 4) is local to protected node #1, but that protector is in ReservedF state
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/tools/llubi/lib/Context.cpp b/llvm/tools/llubi/lib/Context.cpp
index e78263a2bab76e..d723665f2b7eb0 100644
--- a/llvm/tools/llubi/lib/Context.cpp
+++ b/llvm/tools/llubi/lib/Context.cpp
@@ -14,6 +14,9 @@
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <algorithm>
namespace llvm::ubi {
@@ -463,6 +466,10 @@ AnyValue Context::fromBytes(ConstBytesView Bytes, Type *Ty,
SmallVector<APInt::WordType> RawTagBits;
if (Ty->isPointerTy())
RawTagBits.resize(NumWords);
+ bool IsNoAliasValid = ExperimentalNoAlias && Ty->isPointerTy();
+ std::optional<uint64_t> LoadedNoAliasNode;
+ bool SawNoAliasBits = false;
+ bool SawMissingNoAliasBits = false;
for (uint32_t I = 0; I < NumBitsToExtract; I += 8) {
// Try to form a 'logical' byte that represents the bits in the range
// [BitsStart, BitsEnd].
@@ -526,6 +533,22 @@ AnyValue Context::fromBytes(ConstBytesView Bytes, Type *Ty,
IsTagValid = false;
}
}
+ if (IsNoAliasValid) {
+ uint8_t NoAliasMask = LogicalByte.NoAliasMask & Mask;
+ if (NoAliasMask == Mask) {
+ SawNoAliasBits = true;
+ if (!LoadedNoAliasNode)
+ LoadedNoAliasNode = LogicalByte.NoAliasNode;
+ else if (*LoadedNoAliasNode != LogicalByte.NoAliasNode)
+ IsNoAliasValid = false;
+ } else if (!NoAliasMask) {
+ SawMissingNoAliasBits = true;
+ } else {
+ IsNoAliasValid = false;
+ }
+ if (SawNoAliasBits && SawMissingNoAliasBits)
+ IsNoAliasValid = false;
+ }
}
OffsetInBits = NewOffsetInBits;
@@ -563,7 +586,9 @@ AnyValue Context::fromBytes(ConstBytesView Bytes, Type *Ty,
if (IsTagValid) {
APInt Tag(NumBitsToExtract, RawTagBits);
if (auto Prov = TaggedProvenances.lookup(Tag))
- return Pointer(std::move(Prov), Bits);
+ return Pointer(std::move(Prov), Bits,
+ IsNoAliasValid && LoadedNoAliasNode ? *LoadedNoAliasNode
+ : 0);
}
return Pointer(Bits);
}
@@ -665,7 +690,8 @@ void Context::toBytes(const AnyValue &Val, Type *Ty, uint32_t OffsetInBits,
if (PaddingBits)
NewOffsetInBits = alignTo(NewOffsetInBits, 8);
bool NeedsPadding = NewOffsetInBits != OffsetInBits + NumBits;
- auto WriteBits = [&](const APInt &Bits, const APInt *TagBits) {
+ auto WriteBits = [&](const APInt &Bits, const APInt *TagBits,
+ uint64_t NoAliasNode) {
for (uint32_t I = 0, E = Bits.getBitWidth(); I < E; I += 8) {
uint32_t NumBitsInByte = std::min(8U, E - I);
uint32_t BitsStart = OffsetInBits + I;
@@ -697,6 +723,15 @@ void Context::toBytes(const AnyValue &Val, Type *Ty, uint32_t OffsetInBits,
static_cast<uint8_t>((1U << (BitsEnd % 8 + 1)) - 1),
static_cast<uint8_t>(TagBitsVal >> (8 - (BitsStart % 8))));
}
+ if (NoAliasNode) {
+ Bytes[BitsStart / 8].writeNoAliasBits(
+ static_cast<uint8_t>(((1U << NumBitsInByte) - 1)
+ << (BitsStart % 8)),
+ NoAliasNode);
+ if (((BitsStart ^ BitsEnd) & ~7) != 0)
+ Bytes[BitsEnd / 8].writeNoAliasBits(
+ static_cast<uint8_t>((1U << (BitsEnd % 8 + 1)) - 1), NoAliasNode);
+ }
}
};
if (Val.isPoison()) {
@@ -711,19 +746,21 @@ void Context::toBytes(const AnyValue &Val, Type *Ty, uint32_t OffsetInBits,
} else if (Ty->isIntegerTy()) {
auto &Bits = Val.asInteger();
WriteBits(NeedsPadding ? Bits.zext(NewOffsetInBits - OffsetInBits) : Bits,
- /*TagBits=*/nullptr);
+ /*TagBits=*/nullptr, /*NoAliasNode=*/0);
} else if (Ty->isFloatingPointTy()) {
auto Bits = Val.asFloat().bitcastToAPInt();
WriteBits(NeedsPadding ? Bits.zext(NewOffsetInBits - OffsetInBits) : Bits,
- /*TagBits=*/nullptr);
+ /*TagBits=*/nullptr, /*NoAliasNode=*/0);
} else if (Ty->isPointerTy()) {
auto &AddressBits = Val.asPointer().address();
APInt Tag = getTag(AddressBits.getBitWidth(), Val.asPointer().provenance());
if (NeedsPadding)
Tag = Tag.zext(NewOffsetInBits - OffsetInBits);
+ uint64_t NoAliasNode =
+ ExperimentalNoAlias ? Val.asPointer().getNoAliasNodeID() : 0;
WriteBits(NeedsPadding ? AddressBits.zext(NewOffsetInBits - OffsetInBits)
: AddressBits,
- &Tag);
+ &Tag, NoAliasNode);
} else if (Ty->isByteTy()) {
assert(!PaddingBits &&
"Non-vector-element cases should be handled by the fast path.");
@@ -1127,6 +1164,7 @@ bool Context::free(const MemoryObject &Obj) {
UsedMem -= std::max(It->second->getSize(), static_cast<uint64_t>(1));
+ clearNoAliasState(*It->second);
MemoryObject &MutableObj = *It->second;
MutableObj.State = MemoryObjectState::Freed;
MutableObj.Bytes.clear();
@@ -1338,4 +1376,438 @@ bool MemoryObject::isHeapAllocated() const {
llvm_unreachable("Unknown MemAllocKind");
}
+bool Context::isNoAliasAncestor(uint64_t Ancestor, uint64_t Descendant) const {
+ if (!Ancestor || !Descendant)
+ return false;
+ // Parent links are stable while a descendant is active. If a stale node id
+ // was pruned, reaching a missing node means the relationship no longer
+ // exists.
+ for (uint64_t NodeID = Descendant; NodeID;) {
+ if (NodeID == Ancestor)
+ return true;
+ const auto It = NoAliasNodes.find(NodeID);
+ if (It == NoAliasNodes.end())
+ return false;
+ NodeID = It->second.Parent;
+ }
+ return false;
+}
+
+bool Context::hasActiveNoAliasDescendant(uint64_t NodeID) const {
+ for (const auto &[CandidateID, Candidate] : NoAliasNodes) {
+ if (!Candidate.Active || CandidateID == NodeID)
+ continue;
+ if (isNoAliasAncestor(NodeID, CandidateID))
+ return true;
+ }
+ return false;
+}
+
+void Context::tryEraseInactiveNoAliasNode(uint64_t NodeID) {
+ const auto It = NoAliasNodes.find(NodeID);
+ if (It == NoAliasNodes.end() || It->second.Active)
+ return;
+ if (hasActiveNoAliasDescendant(NodeID))
+ return;
+
+ // An inactive node can still be relevant as the parent of a live child. Once
+ // that is no longer true, stale pointers carrying this ID should behave like
+ // raw/root pointers during future retagging.
+ const uint64_t Parent = It->second.Parent;
+ appendNoAliasEvent("erased inactive protector " + getNoAliasNodeName(NodeID));
+ NoAliasNodes.erase(It);
+ if (Parent)
+ tryEraseInactiveNoAliasNode(Parent);
+}
+
+StringRef Context::getNoAliasAccessKindName(NoAliasAccessKind Kind) {
+ switch (Kind) {
+ case NoAliasAccessKind::Read:
+ return "read";
+ case NoAliasAccessKind::Write:
+ return "write";
+ }
+ llvm_unreachable("Unknown NoAliasAccessKind");
+}
+
+StringRef Context::getNoAliasStateName(NoAliasState State) {
+ switch (State) {
+ case NoAliasState::Reserved:
+ return "Reserved";
+ case NoAliasState::ReservedL:
+ return "ReservedL";
+ case NoAliasState::ReservedF:
+ return "ReservedF";
+ case NoAliasState::ReservedLF:
+ return "ReservedLF";
+ case NoAliasState::Unique:
+ return "Unique";
+ case NoAliasState::Disabled:
+ return "Disabled";
+ case NoAliasState::Dummy:
+ return "Dummy";
+ }
+ llvm_unreachable("Unknown NoAliasState");
+}
+
+std::string Context::getNoAliasNodeName(uint64_t NodeID) {
+ if (!NodeID)
+ return "raw/root";
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "node #" << NodeID;
+ return S;
+}
+
+std::string Context::getNoAliasObjectName(const MemoryObject &MO) {
+ if (MO.getName().empty()) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "object at 0x";
+ OS.write_hex(MO.getAddress());
+ return S;
+ }
+ return ("'" + MO.getName() + "'").str();
+}
+
+void Context::appendNoAliasEvent(std::string Msg) {
+ NoAliasEvents.push_back(std::move(Msg));
+}
+
+void Context::setNoAliasViolation(uint64_t ProtectedNodeId, uint64_t AccessNode,
+ const MemoryObject &MO, uint64_t Begin,
+ uint64_t End, NoAliasAccessKind Kind,
+ bool IsLocal, NoAliasState State,
+ bool IsProtectorEndAction) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "noalias ";
+ if (IsProtectorEndAction)
+ OS << "protector end ";
+ OS << "violation: " << getNoAliasAccessKindName(Kind) << " through "
+ << getNoAliasNodeName(AccessNode) << " on " << getNoAliasObjectName(MO)
+ << " bytes [" << Begin << ", " << End << ") is "
+ << (IsLocal ? "local" : "foreign") << " to protected "
+ << getNoAliasNodeName(ProtectedNodeId) << ", but that protector is in "
+ << getNoAliasStateName(State) << " state";
+ LastNoAliasError = std::move(S);
+ appendNoAliasEvent(LastNoAliasError);
+}
+
+std::optional<Context::NoAliasState>
+Context::transitionNoAliasState(NoAliasState State, NoAliasAccessKind Kind,
+ bool IsLocal) {
+ if (State == NoAliasState::Dummy)
+ return NoAliasState::Dummy;
+
+ // For the complete state machine, please refer to the original blog
+ // https://jhostert.de/blog/2025/noalias/.
+ const bool IsWrite = Kind == NoAliasAccessKind::Write;
+ switch (State) {
+ case NoAliasState::Reserved: {
+ if (!IsWrite)
+ return IsLocal ? NoAliasState::ReservedL : NoAliasState::ReservedF;
+ return IsLocal ? NoAliasState::Unique : NoAliasState::Disabled;
+ }
+ case NoAliasState::ReservedL: {
+ if (IsLocal)
+ return IsWrite ? NoAliasState::Unique : NoAliasState::ReservedL;
+ if (!IsWrite)
+ return NoAliasState::ReservedLF;
+ return std::nullopt;
+ }
+ case NoAliasState::ReservedF: {
+ if (!IsLocal)
+ return IsWrite ? NoAliasState::Disabled : NoAliasState::ReservedF;
+ if (!IsWrite)
+ return NoAliasState::ReservedLF;
+ return std::nullopt;
+ }
+ case NoAliasState::ReservedLF: {
+ if (!IsWrite)
+ return NoAliasState::ReservedLF;
+ return std::nullopt;
+ }
+ case NoAliasState::Unique: {
+ if (IsLocal)
+ return NoAliasState::Unique;
+ return std::nullopt;
+ }
+ case NoAliasState::Disabled: {
+ if (!IsLocal)
+ return NoAliasState::Disabled;
+ return std::nullopt;
+ }
+ case NoAliasState::Dummy:
+ llvm_unreachable("Dummy state should be handled earlier");
+ }
+ llvm_unreachable("Unknown NoAliasState");
+}
+
+bool Context::accessNoAliasImpl(MemoryObject &MO, uint64_t Offset,
+ uint64_t Size, uint64_t AccessNode,
+ NoAliasAccessKind Kind,
+ uint64_t SkipDescendantsOf) {
+ if (!ActiveNoAliasScopes || !Size)
+ return true;
+
+ const auto It = NoAliasNodesByObject.find(&MO);
+ if (It == NoAliasNodesByObject.end())
+ return true;
+
+ const uint64_t End = Offset + Size;
+ uint32_t CheckedNodes = 0;
+ for (uint64_t NodeID : It->second) {
+ auto NodeIt = NoAliasNodes.find(NodeID);
+ if (NodeIt == NoAliasNodes.end() || !NodeIt->second.Active)
+ continue;
+ if (SkipDescendantsOf && NodeID != SkipDescendantsOf &&
+ isNoAliasAncestor(SkipDescendantsOf, NodeID))
+ continue;
+ ++CheckedNodes;
+ // A protected node judges the same concrete memory access differently
+ // depending on whether the pointer used for the access is in its subtree.
+ if (const bool IsLocal = isNoAliasAncestor(NodeID, AccessNode);
+ !updateNoAliasNodeForAccess(
+ NodeIt->second, Offset, End, Kind, IsLocal, NodeID, AccessNode,
+ /*IsProtectorEndAction=*/SkipDescendantsOf != 0))
+ return false;
+ }
+ if (CheckedNodes && !SkipDescendantsOf) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << getNoAliasAccessKindName(Kind) << " through "
+ << getNoAliasNodeName(AccessNode) << " on " << getNoAliasObjectName(MO)
+ << " bytes [" << Offset << ", " << End << ") checked " << CheckedNodes
+ << " active noalias protector" << (CheckedNodes == 1 ? "" : "s");
+ appendNoAliasEvent(std::move(S));
+ }
+ return true;
+}
+
+bool Context::updateNoAliasNodeForAccess(NoAliasNode &Node, uint64_t Begin,
+ uint64_t End, NoAliasAccessKind Kind,
+ bool IsLocal, uint64_t ProtectedNodeID,
+ uint64_t AccessNode,
+ bool IsProtectorEndAction) {
+ assert(Begin < End && "empty accesses should not reach noalias tracking");
+
+ SmallVector<NoAliasStateRun, 4> NewRuns;
+ auto AppendRun = [&](uint64_t RunBegin, uint64_t RunEnd, NoAliasState State) {
+ if (RunBegin == RunEnd || State == NoAliasState::Reserved)
+ return;
+ if (!NewRuns.empty() && NewRuns.back().End == RunBegin &&
+ NewRuns.back().State == State) {
+ NewRuns.back().End = RunEnd;
+ return;
+ }
+ NewRuns.push_back({RunBegin, RunEnd, State});
+ };
+
+ auto AppendTransitioned = [&](uint64_t RunBegin, uint64_t RunEnd,
+ NoAliasState State) -> bool {
+ if (RunBegin == RunEnd)
+ return true;
+ std::optional<NoAliasState> NewState =
+ transitionNoAliasState(State, Kind, IsLocal);
+ if (!NewState) {
+ setNoAliasViolation(ProtectedNodeID, AccessNode, *Node.Object, RunBegin,
+ RunEnd, Kind, IsLocal, State, IsProtectorEndAction);
+ return false;
+ }
+ std::string S;
+ raw_string_ostream OS(S);
+ if (IsProtectorEndAction)
+ OS << "protector end: ";
+ OS << getNoAliasNodeName(ProtectedNodeID) << ' '
+ << (IsLocal ? "local" : "foreign") << ' '
+ << getNoAliasAccessKindName(Kind) << " through "
+ << getNoAliasNodeName(AccessNode) << " on "
+ << getNoAliasObjectName(*Node.Object) << " bytes [" << RunBegin << ", "
+ << RunEnd << "): " << getNoAliasStateName(State) << " -> "
+ << getNoAliasStateName(*NewState);
+ appendNoAliasEvent(std::move(S));
+ AppendRun(RunBegin, RunEnd, *NewState);
+ return true;
+ };
+
+ uint64_t Cur = Begin;
+ bool InsertedAccessTail = false;
+ for (const NoAliasStateRun &Run : Node.States) {
+ if (Run.End <= Begin) {
+ AppendRun(Run.Begin, Run.End, Run.State);
+ continue;
+ }
+ if (Run.Begin >= End) {
+ if (!InsertedAccessTail) {
+ // The access ends before this run begins, so [Cur, End) is an implicit
+ // Reserved gap that still needs transition.
+ if (!AppendTransitioned(Cur, End, NoAliasState::Reserved))
+ return false;
+ InsertedAccessTail = true;
+ }
+ AppendRun(Run.Begin, Run.End, Run.State);
+ continue;
+ }
+
+ if (Run.Begin < Begin)
+ AppendRun(Run.Begin, Begin, Run.State);
+
+ const uint64_t OverlapBegin = std::max(Cur, Run.Begin);
+ // Any gap between the previous covered byte and this run is also implicit
+ // Reserved state.
+ if (!AppendTransitioned(Cur, OverlapBegin, NoAliasState::Reserved))
+ return false;
+
+ const uint64_t OverlapEnd = std::min(End, Run.End);
+ if (!AppendTransitioned(OverlapBegin, OverlapEnd, Run.State))
+ return false;
+ Cur = OverlapEnd;
+
+ if (Run.End > End) {
+ AppendRun(End, Run.End, Run.State);
+ InsertedAccessTail = true;
+ }
+ }
+ if (!InsertedAccessTail) {
+ if (!AppendTransitioned(Cur, End, NoAliasState::Reserved))
+ return false;
+ }
+
+ Node.States = std::move(NewRuns);
+ return true;
+}
+
+Pointer Context::createNoAliasPointer(const Pointer &Ptr) {
+ if (!ExperimentalNoAlias)
+ return Ptr;
+
+ MemoryObject *MO = Ptr.getMemoryObject();
+ if (!MO)
+ return Ptr;
+
+ const uint64_t NodeID = NextNoAliasNode++;
+ uint64_t Parent = Ptr.getNoAliasNodeID();
+ // If the parent node was pruned after its protector ended, the incoming
+ // pointer is treated as a raw/root-derived pointer for this new scope.
+ if (Parent && NoAliasNodes.find(Parent) == NoAliasNodes.end())
+ Parent = 0;
+ NoAliasNode Node;
+ Node.Parent = Parent;
+ Node.Object = MO;
+ Node.Active = true;
+ NoAliasNodes.try_emplace(NodeID, std::move(Node));
+ NoAliasNodesByObject[MO].push_back(NodeID);
+ ++ActiveNoAliasScopes;
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "created protector " << getNoAliasNodeName(NodeID) << " for "
+ << getNoAliasObjectName(*MO) << " based on " << getNoAliasNodeName(Parent);
+ appendNoAliasEvent(std::move(S));
+ return Ptr.getWithNoAliasNode(NodeID);
+}
+
+bool Context::accessNoAlias(MemoryObject &MO, uint64_t Offset, uint64_t Size,
+ uint64_t AccessNode, NoAliasAccessKind Kind) {
+ if (!ExperimentalNoAlias)
+ return true;
+
+ return accessNoAliasImpl(MO, Offset, Size, AccessNode, Kind,
+ /*SkipDescendantsOf=*/0);
+}
+
+bool Context::endNoAliasScopes(ArrayRef<uint64_t> Nodes) {
+ if (!ExperimentalNoAlias)
+ return true;
+
+ for (uint64_t NodeID : Nodes) {
+ auto It = NoAliasNodes.find(NodeID);
+ if (It == NoAliasNodes.end() || !It->second.Active)
+ continue;
+
+ SmallVector<NoAliasStateRun, 4> States(It->second.States.begin(),
+ It->second.States.end());
+ for (const NoAliasStateRun &Run : States) {
+ std::optional<NoAliasAccessKind> EndAction;
+ // Protector end actions. Quote from the original blog:
+ // "Unique triggers writes, ReservedL and ReservedLF triggers reads, and
+ // the other states trigger nothing since they have not yet been locally
+ // accessed. Like in Tree Borrows, these end actions are “special” in
+ // that they don’t affect children of the node which was protected."
+ switch (Run.State) {
+ case NoAliasState::Unique:
+ EndAction = NoAliasAccessKind::Write;
+ break;
+ case NoAliasState::ReservedL:
+ case NoAliasState::ReservedLF:
+ EndAction = NoAliasAccessKind::Read;
+ break;
+ case NoAliasState::Reserved:
+ case NoAliasState::ReservedF:
+ case NoAliasState::Disabled:
+ case NoAliasState::Dummy:
+ break;
+ }
+ if (EndAction) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "protector end for " << getNoAliasNodeName(NodeID)
+ << " triggers synthetic " << getNoAliasAccessKindName(*EndAction)
+ << " on " << getNoAliasObjectName(*It->second.Object) << " bytes ["
+ << Run.Begin << ", " << Run.End << ")";
+ appendNoAliasEvent(std::move(S));
+ if (!accessNoAliasImpl(*It->second.Object, Run.Begin,
+ Run.End - Run.Begin, NodeID, *EndAction,
+ /*SkipDescendantsOf=*/NodeID))
+ return false;
+ }
+ }
+
+ It->second.Active = false;
+ It->second.States.clear();
+ // Remove inactive nodes from the per-object active list immediately, but
+ // keep the node record itself until no active child depends on its parent
+ // identity.
+ if (auto ObjIt = NoAliasNodesByObject.find(It->second.Object);
+ ObjIt != NoAliasNodesByObject.end()) {
+ SmallVectorImpl<uint64_t> &ObjectNodes = ObjIt->second;
+ ObjectNodes.erase(
+ std::remove(ObjectNodes.begin(), ObjectNodes.end(), NodeID),
+ ObjectNodes.end());
+ if (ObjectNodes.empty())
+ NoAliasNodesByObject.erase(ObjIt);
+ }
+ assert(ActiveNoAliasScopes && "mismatched noalias protector count");
+ --ActiveNoAliasScopes;
+ appendNoAliasEvent("ended protector " + getNoAliasNodeName(NodeID));
+ tryEraseInactiveNoAliasNode(NodeID);
+ }
+ return true;
+}
+
+SmallVector<std::string, 4> Context::takeNoAliasEvents() {
+ SmallVector<std::string, 8> Events;
+ Events.swap(NoAliasEvents);
+ return Events;
+}
+
+void Context::clearNoAliasState(const MemoryObject &MO) {
+ if (!ExperimentalNoAlias)
+ return;
+
+ const auto It = NoAliasNodesByObject.find(&MO);
+ if (It == NoAliasNodesByObject.end())
+ return;
+ for (uint64_t NodeID : It->second) {
+ auto NodeIt = NoAliasNodes.find(NodeID);
+ if (NodeIt == NoAliasNodes.end() || !NodeIt->second.Active)
+ continue;
+ NodeIt->second.Active = false;
+ NodeIt->second.States.clear();
+ assert(ActiveNoAliasScopes && "mismatched noalias protector count");
+ --ActiveNoAliasScopes;
+ }
+ NoAliasNodesByObject.erase(It);
+}
+
} // namespace llvm::ubi
diff --git a/llvm/tools/llubi/lib/Context.h b/llvm/tools/llubi/lib/Context.h
index 571be140cc83f9..a8d968f5ca4eb0 100644
--- a/llvm/tools/llubi/lib/Context.h
+++ b/llvm/tools/llubi/lib/Context.h
@@ -19,6 +19,7 @@
#include <map>
#include <optional>
#include <random>
+#include <string>
namespace llvm::ubi {
@@ -101,6 +102,8 @@ struct ProgramExitInfo {
}
};
+enum class NoAliasAccessKind { Read, Write };
+
class MemoryObject : public RefCountedBase<MemoryObject> {
uint64_t Address;
uint64_t Size;
@@ -178,6 +181,7 @@ class EventHandler {
return true;
}
virtual void onProgramExit(const ProgramExitInfo &ExitInfo) {}
+ virtual bool onNoAliasEvent(StringRef Msg) { return true; }
virtual bool onPrint(StringRef Msg) {
outs() << Msg;
outs().flush();
@@ -237,6 +241,7 @@ class Context {
UndefValueBehavior UndefBehavior = UndefValueBehavior::NonDeterministic;
NaNPropagationBehavior NaNBehavior = NaNPropagationBehavior::NonDeterministic;
bool FusedMultiplyAdd = false;
+ bool ExperimentalNoAlias = false;
std::mt19937_64 Rng;
/// Always returns a random APInt value. It is not controlled by
@@ -291,6 +296,49 @@ class Context {
/// Get the tag for the given pointer provenance.
APInt getTag(uint32_t BitWidth, Provenance &Prov);
+
+ /// Experimental noalias states (see https://jhostert.de/blog/2025/noalias/).
+ /// The states Frozen and FrozenL from the original state machine are omitted
+ /// as proposed. Note that the Reserved state is the implicit default and is
+ /// intentionally omitted from sparse state runs below.
+ enum class NoAliasState : uint8_t {
+ Reserved,
+ ReservedL,
+ ReservedF,
+ ReservedLF,
+ Unique,
+ Disabled,
+ Dummy,
+ };
+
+ /// A non-Reserved state over the byte interval [Begin, End).
+ struct NoAliasStateRun {
+ uint64_t Begin;
+ uint64_t End;
+ NoAliasState State;
+ };
+
+ /// A protected noalias node created by retagging a noalias function argument.
+ /// Parent is another noalias node, or 0 for the raw/root parent. The
+ /// underlying pointer provenance remains represented by Pointer::Obj.
+ struct NoAliasNode {
+ uint64_t Parent = 0;
+ MemoryObject *Object = nullptr;
+ bool Active = false;
+ // Run-Length Encoding to reduce memory consumption.
+ SmallVector<NoAliasStateRun, 1> States;
+ };
+
+ // The node ID 0 is reserved for raw/root nodes.
+ uint64_t NextNoAliasNode = 1;
+ uint64_t ActiveNoAliasScopes = 0;
+ DenseMap<uint64_t, NoAliasNode> NoAliasNodes;
+ DenseMap<MemoryObject *, SmallVector<uint64_t, 2>> NoAliasNodesByObject;
+
+ // noalias-related diagnostics
+ std::string LastNoAliasError;
+ SmallVector<std::string, 4> NoAliasEvents;
+
AnyValue fromBytes(ConstBytesView Bytes, Type *Ty, uint32_t OffsetInBits,
bool CheckPaddingBits, bool *ContainsUndefinedBits);
void toBytes(const AnyValue &Val, Type *Ty, uint32_t OffsetInBits,
@@ -304,6 +352,44 @@ class Context {
const APInt &Scale, GEPNoWrapFlags Flags,
AnyValue &AccumulatedOffset);
+ /// Return whether \p Ancestor is on \p Descendant's noalias parent chain.
+ /// This relation defines whether an access is local to a protected node.
+ bool isNoAliasAncestor(uint64_t Ancestor, uint64_t Descendant) const;
+ bool hasActiveNoAliasDescendant(uint64_t NodeID) const;
+ /// Try to erase the node if it is inactive and has no active descendant.
+ void tryEraseInactiveNoAliasNode(uint64_t NodeID);
+ static StringRef getNoAliasAccessKindName(NoAliasAccessKind Kind);
+ static StringRef getNoAliasStateName(NoAliasState State);
+ static std::string getNoAliasNodeName(uint64_t NodeID);
+ static std::string getNoAliasObjectName(const MemoryObject &MO);
+ void appendNoAliasEvent(std::string Msg);
+ /// Record a noalias violation in both the user-facing error slot and verbose
+ /// event queue.
+ void setNoAliasViolation(uint64_t ProtectedNodeId, uint64_t AccessNode,
+ const MemoryObject &MO, uint64_t Begin, uint64_t End,
+ NoAliasAccessKind Kind, bool IsLocal,
+ NoAliasState State, bool IsProtectorEndAction);
+ /// Apply the noalias state machine for one homogeneous byte range. Returns
+ /// std::nullopt when the access is forbidden and should be reported as an
+ /// immediate UB.
+ static std::optional<NoAliasState>
+ transitionNoAliasState(NoAliasState State, NoAliasAccessKind Kind,
+ bool IsLocal);
+ /// Apply a memory access to every active protector for \p MO. \p
+ /// SkipDescendantsOf is used for protector-end synthetic accesses.
+ bool accessNoAliasImpl(MemoryObject &MO, uint64_t Offset, uint64_t Size,
+ uint64_t AccessNode, NoAliasAccessKind Kind,
+ uint64_t SkipDescendantsOf);
+ /// Update one node's sparse byte-state runs for access to [Begin, End).
+ /// The nodes store only non-Reserved runs, so this routine splits old runs,
+ /// treats gaps as implicit Reserved ranges, transitions each touches segment,
+ /// and coalesces adjacent ranges that end in the same non-Reserved state.
+ bool updateNoAliasNodeForAccess(NoAliasNode &Node, uint64_t Begin,
+ uint64_t End, NoAliasAccessKind Kind,
+ bool IsLocal, uint64_t ProtectedNodeID,
+ uint64_t AccessNode,
+ bool IsProtectorEndAction);
+
// Constants
// Use std::map to avoid iterator/reference invalidation.
std::map<Constant *, MaterializedConstant> ConstCache;
@@ -341,6 +427,7 @@ class Context {
void setMaxSteps(uint32_t MS) { MaxSteps = MS; }
void setMaxStackDepth(uint32_t Depth) { MaxStackDepth = Depth; }
void setFusedMultiplyAdd(bool F) { FusedMultiplyAdd = F; }
+ void setExperimentalNoAlias(bool Enabled) { ExperimentalNoAlias = Enabled; }
uint64_t getMemoryLimit() const { return MaxMem; }
uint32_t getVScale() const { return VScale; }
uint32_t getMaxSteps() const { return MaxSteps; }
@@ -351,6 +438,7 @@ class Context {
UndefValueBehavior getEffectiveUndefValueBehavior() const;
NaNPropagationBehavior getEffectiveNaNPropagationBehavior() const;
bool fuseMultiplyAdd() const { return FusedMultiplyAdd; }
+ bool isExperimentalNoAliasEnabled() const { return ExperimentalNoAlias; }
void setUndefValueBehavior(UndefValueBehavior UB) { UndefBehavior = UB; }
void setNaNPropagationBehavior(NaNPropagationBehavior NaNBehav) {
NaNBehavior = NaNBehav;
@@ -438,6 +526,20 @@ class Context {
Function *getTargetFunction(const Pointer &Ptr);
BasicBlock *getTargetBlock(const Pointer &Ptr);
+ /// Create a new protected noalias node based on \p Ptr and return a pointer
+ /// associated with that node. The underlying pointer provenance is unchanged.
+ Pointer createNoAliasPointer(const Pointer &Ptr);
+ /// Apply a memory access to the active noalias state machines for \p MO.
+ /// Returns false when the protected state machine detects UB.
+ bool accessNoAlias(MemoryObject &MO, uint64_t Offset, uint64_t Size,
+ uint64_t AccessNode, NoAliasAccessKind Kind);
+ /// End all noalias protectors created for a call frame.
+ bool endNoAliasScopes(ArrayRef<uint64_t> Nodes);
+ StringRef getLastNoAliasError() const { return LastNoAliasError; }
+ SmallVector<std::string, 4> takeNoAliasEvents();
+ /// Drop noalias state for an object \p MO that is no longer usable.
+ void clearNoAliasState(const MemoryObject &MO);
+
/// Initialize global variables and function/block objects. This function
/// should be called before executing any function. Returns false if the
/// initialization fails (e.g., the memory limit is exceeded during
diff --git a/llvm/tools/llubi/lib/ExecutorBase.cpp b/llvm/tools/llubi/lib/ExecutorBase.cpp
index 0cbb38073f652a..5bc53de09362a3 100644
--- a/llvm/tools/llubi/lib/ExecutorBase.cpp
+++ b/llvm/tools/llubi/lib/ExecutorBase.cpp
@@ -13,18 +13,29 @@
#include "ExecutorBase.h"
namespace llvm::ubi {
-Frame::Frame(Function &F, CallBase *CallSite, Frame *LastFrame,
- ArrayRef<AnyValue> Args, AnyValue &RetVal,
- const TargetLibraryInfoImpl &TLIImpl)
+Frame::Frame(Context &Ctx, Function &F, CallBase *CallSite, Frame *LastFrame,
+ ArrayRef<AnyValue> Args, AnyValue &RetVal)
: Func(F), LastFrame(LastFrame), CallSite(CallSite), Args(Args),
- RetVal(RetVal), TLI(TLIImpl, &F) {
+ RetVal(RetVal), TLI(Ctx.getTLIImpl(), &F) {
assert((Args.size() == F.arg_size() ||
(F.isVarArg() && Args.size() >= F.arg_size())) &&
"Expected enough arguments to call the function.");
BB = &Func.getEntryBlock();
PC = BB->begin();
- for (Argument &Arg : F.args())
- ValueMap[&Arg] = Args[Arg.getArgNo()];
+ for (Argument &Arg : F.args()) {
+ AnyValue ArgValue = Args[Arg.getArgNo()];
+ // Retag only callee-visible noalias pointer parameters. This creates the
+ // protected node for the dynamic call frame without changing the normal
+ // provenance carried by the pointer.
+ if (Ctx.isExperimentalNoAliasEnabled() && Arg.hasNoAliasAttr() &&
+ Arg.getType()->isPointerTy() && !ArgValue.isPoison()) {
+ Pointer Retagged = Ctx.createNoAliasPointer(ArgValue.asPointer());
+ if (uint64_t NodeID = Retagged.getNoAliasNodeID())
+ NoAliasNodes.push_back(NodeID);
+ ArgValue = Retagged;
+ }
+ ValueMap[&Arg] = std::move(ArgValue);
+ }
}
DiagnosticReporter ExecutorBase::reportImmediateUB() {
@@ -35,6 +46,11 @@ DiagnosticReporter ExecutorBase::reportError() {
return DiagnosticReporter(*this, DiagnosticKind::Error);
}
+void ExecutorBase::flushNoAliasEvents() {
+ for (const std::string &Msg : Ctx.takeNoAliasEvents())
+ Handler.onNoAliasEvent(Msg);
+}
+
void ExecutorBase::reportImmediateUBString(StringRef Msg) {
// Check if we have already reported an immediate UB.
if (hasProgramExited())
@@ -131,6 +147,18 @@ AnyValue ExecutorBase::load(const AnyValue &Ptr, Align Alignment, Type *ValTy,
NoUndef ? &ContainsUndefinedBits : nullptr);
if (NoUndef && ContainsUndefinedBits)
reportImmediateUB() << "The value loaded contains undefined bits.";
+
+ // Run noalias after ordinary memory validity checks so diagnostics report
+ // aliasing only for otherwise valid concrete accesses.
+ if (const uint64_t AccessSize = Ctx.getEffectiveTypeStoreSize(ValTy);
+ !Ctx.accessNoAlias(*MO, Offset, AccessSize, PtrVal.getNoAliasNodeID(),
+ NoAliasAccessKind::Read)) {
+ flushNoAliasEvents();
+ reportImmediateUB() << Ctx.getLastNoAliasError();
+ return AnyValue::getPoisonValue(Ctx, ValTy);
+ }
+ flushNoAliasEvents();
+
return Res;
}
return AnyValue::getPoisonValue(Ctx, ValTy);
@@ -146,8 +174,17 @@ void ExecutorBase::store(const AnyValue &Ptr, Align Alignment,
if (auto [MO, Offset] = verifyMemAccess(
PtrVal, Ctx.getEffectiveTypeStoreSize(ValTy), Alignment,
/*IsStore=*/true);
- MO)
+ MO) {
+ if (const uint64_t AccessSize = Ctx.getEffectiveTypeStoreSize(ValTy);
+ !Ctx.accessNoAlias(*MO, Offset, AccessSize, PtrVal.getNoAliasNodeID(),
+ NoAliasAccessKind::Write)) {
+ flushNoAliasEvents();
+ reportImmediateUB() << Ctx.getLastNoAliasError();
+ return;
+ }
+ flushNoAliasEvents();
Ctx.store(*MO, Offset, Val, ValTy);
+ }
}
void ExecutorBase::requestProgramExit(ProgramExitInfo::ProgramExitKind Kind,
diff --git a/llvm/tools/llubi/lib/ExecutorBase.h b/llvm/tools/llubi/lib/ExecutorBase.h
index ff8025d189615c..815ee7b5700fc4 100644
--- a/llvm/tools/llubi/lib/ExecutorBase.h
+++ b/llvm/tools/llubi/lib/ExecutorBase.h
@@ -58,6 +58,8 @@ struct Frame {
// Stack objects allocated in this frame. They will be automatically freed
// when the function returns.
SmallVector<IntrusiveRefCntPtr<MemoryObject>> Allocas;
+ // Protected noalias nodes created for this frame's arguments
+ SmallVector<uint64_t, 4> NoAliasNodes;
// Values of arguments and executed instructions in this function.
DenseMap<Value *, AnyValue> ValueMap;
@@ -69,9 +71,8 @@ struct Frame {
SmallVector<IntrusiveRefCntPtr<MemoryObject>> CalleeByValArgs;
AnyValue CalleeRetVal;
- Frame(Function &F, CallBase *CallSite, Frame *LastFrame,
- ArrayRef<AnyValue> Args, AnyValue &RetVal,
- const TargetLibraryInfoImpl &TLIImpl);
+ Frame(Context &Ctx, Function &F, CallBase *CallSite, Frame *LastFrame,
+ ArrayRef<AnyValue> Args, AnyValue &RetVal);
};
enum class DiagnosticKind {
@@ -102,6 +103,8 @@ class ExecutorBase {
DiagnosticReporter reportImmediateUB();
DiagnosticReporter reportError();
+ void flushNoAliasEvents();
+
/// Check if the upcoming memory access is valid. Returns the resolved memory
/// object and offset if it is valid.
std::pair<MemoryObject *, uint64_t> verifyMemAccess(const Pointer &Ptr,
diff --git a/llvm/tools/llubi/lib/Interpreter.cpp b/llvm/tools/llubi/lib/Interpreter.cpp
index 0c7e74f52f6890..c159fea539b162 100644
--- a/llvm/tools/llubi/lib/Interpreter.cpp
+++ b/llvm/tools/llubi/lib/Interpreter.cpp
@@ -924,8 +924,8 @@ class InstExecutor : public InstVisitor<InstExecutor, void>,
ArrayRef<AnyValue> Args, AnyValue &RetVal)
: ExecutorBase(C, H), DL(Ctx.getDataLayout()),
Lib(Ctx, Handler, DL, static_cast<ExecutorBase &>(*this)) {
- CallStack.emplace_back(F, /*CallSite=*/nullptr, /*LastFrame=*/nullptr, Args,
- RetVal, Ctx.getTLIImpl());
+ CallStack.emplace_back(Ctx, F, /*CallSite=*/nullptr, /*LastFrame=*/nullptr,
+ Args, RetVal);
}
void visitReturnInst(ReturnInst &RI) {
@@ -2183,8 +2183,7 @@ class InstExecutor : public InstVisitor<InstExecutor, void>,
ArrayRef<AnyValue> Args = CurrentFrame->CalleeArgs;
AnyValue &RetVal = CurrentFrame->CalleeRetVal;
CurrentFrame->State = FrameState::Pending;
- CallStack.emplace_back(*Callee, &CB, CurrentFrame, Args, RetVal,
- Ctx.getTLIImpl());
+ CallStack.emplace_back(Ctx, *Callee, &CB, CurrentFrame, Args, RetVal);
}
}
@@ -2832,6 +2831,7 @@ class InstExecutor : public InstVisitor<InstExecutor, void>,
CurrentFrame = &Top;
if (Top.State == FrameState::Entry) {
Handler.onFunctionEntry(Top.Func, Top.Args, Top.CallSite);
+ flushNoAliasEvents();
} else {
assert(Top.State == FrameState::Pending &&
"Expected to return from a callee.");
@@ -2872,6 +2872,14 @@ class InstExecutor : public InstVisitor<InstExecutor, void>,
if (Top.State == FrameState::Exit) {
assert((Top.Func.getReturnType()->isVoidTy() || !Top.RetVal.isNone()) &&
"Expected return value to be set on function exit.");
+ // End protectors before freeing frame allocas: protector end actions
+ // are still accesses to the protected memory object.
+ if (!Ctx.endNoAliasScopes(Top.NoAliasNodes)) {
+ flushNoAliasEvents();
+ reportImmediateUB() << Ctx.getLastNoAliasError();
+ break;
+ }
+ flushNoAliasEvents();
Handler.onFunctionExit(Top.Func, Top.RetVal);
// Free stack objects allocated in this frame.
for (auto &Obj : Top.Allocas)
diff --git a/llvm/tools/llubi/lib/Value.h b/llvm/tools/llubi/lib/Value.h
index b0f90aab2f1b59..739574e698d0b6 100644
--- a/llvm/tools/llubi/lib/Value.h
+++ b/llvm/tools/llubi/lib/Value.h
@@ -42,13 +42,15 @@ class AnyValue;
struct Byte {
uint8_t ConcreteMask;
uint8_t Value;
- uint8_t TagMask; // A mask to indicate which bits are pointer bits.
- uint8_t TagValue; // For each pointer bit, the corresponding bit of the tag
- // for provenance tracking.
+ uint8_t TagMask; // A mask to indicate which bits are pointer bits.
+ uint8_t TagValue; // For each pointer bit, the corresponding bit of the
+ // tag for provenance tracking.
+ uint8_t NoAliasMask; // A mask to indicate which bits carry a noalias node.
+ uint64_t NoAliasNode; // Shadow noalias node id for pointer bits.
- static Byte poison() { return Byte{0, 0, 0, 0}; }
- static Byte undef() { return Byte{0, 255, 0, 0}; }
- static Byte concrete(uint8_t Val) { return Byte{255, Val, 0, 0}; }
+ static Byte poison() { return Byte{0, 0, 0, 0, 0, 0}; }
+ static Byte undef() { return Byte{0, 255, 0, 0, 0, 0}; }
+ static Byte concrete(uint8_t Val) { return Byte{255, Val, 0, 0, 0, 0}; }
void zeroBits(uint8_t Mask) {
ConcreteMask |= Mask;
@@ -72,6 +74,7 @@ struct Byte {
ConcreteMask |= Mask;
Value = (Value & ~Mask) | (Val & Mask);
TagMask &= ~Mask;
+ NoAliasMask &= ~Mask;
}
void writeTagBits(uint8_t Mask, uint8_t Tag) {
@@ -87,6 +90,23 @@ struct Byte {
Value = (Value & ~Mask) | (RHS.Value & Mask);
TagMask = (TagMask & ~Mask) | (RHS.TagMask & Mask);
TagValue = (TagValue & ~Mask) | (RHS.TagValue & Mask);
+ NoAliasMask = (NoAliasMask & ~Mask) | (RHS.NoAliasMask & Mask);
+ if (RHS.NoAliasMask & Mask)
+ NoAliasNode = RHS.NoAliasNode;
+ }
+
+ void writeNoAliasBits(uint8_t Mask, uint64_t NodeID) {
+ assert((ConcreteMask & Mask) == Mask &&
+ "Please ensure pointer bits are concrete before calling "
+ "writeNoAliasBits.");
+ if (!NodeID) {
+ NoAliasMask &= ~Mask;
+ return;
+ }
+ if (NoAliasMask && NoAliasNode != NodeID)
+ NoAliasMask = 0;
+ NoAliasNode = NodeID;
+ NoAliasMask |= Mask;
}
/// Returns a logical byte that is part of two adjacent bytes.
@@ -95,26 +115,38 @@ struct Byte {
/// LSB | 0 1 0 1 0 1 0 1 | 0 0 0 0 1 1 1 1 | MSB
/// Result = | 1 0 1 0 0 0 0 1 |
static Byte fshr(const Byte &Low, const Byte &High, uint32_t ShAmt) {
+ uint16_t NoAliasMask = Low.NoAliasMask | (High.NoAliasMask << 8);
+ uint64_t NoAliasNode = Low.NoAliasNode;
+ if (Low.NoAliasMask && High.NoAliasMask &&
+ Low.NoAliasNode != High.NoAliasNode)
+ NoAliasMask = 0;
+ else if (!Low.NoAliasMask)
+ NoAliasNode = High.NoAliasNode;
return Byte{
static_cast<uint8_t>((Low.ConcreteMask | (High.ConcreteMask << 8)) >>
ShAmt),
static_cast<uint8_t>((Low.Value | (High.Value << 8)) >> ShAmt),
static_cast<uint8_t>((Low.TagMask | (High.TagMask << 8)) >> ShAmt),
- static_cast<uint8_t>((Low.TagValue | (High.TagValue << 8)) >> ShAmt)};
+ static_cast<uint8_t>((Low.TagValue | (High.TagValue << 8)) >> ShAmt),
+ static_cast<uint8_t>(NoAliasMask >> ShAmt),
+ NoAliasNode};
}
Byte lshr(uint8_t Shift) const {
return Byte{static_cast<uint8_t>(ConcreteMask >> Shift),
static_cast<uint8_t>(Value >> Shift),
static_cast<uint8_t>(TagMask >> Shift),
- static_cast<uint8_t>(TagValue >> Shift)};
+ static_cast<uint8_t>(TagValue >> Shift),
+ static_cast<uint8_t>(NoAliasMask >> Shift),
+ NoAliasNode};
}
Byte shl(uint8_t Shift) const {
return Byte{static_cast<uint8_t>(ConcreteMask << Shift),
static_cast<uint8_t>(Value << Shift),
static_cast<uint8_t>(TagMask << Shift),
- static_cast<uint8_t>(TagValue << Shift)};
+ static_cast<uint8_t>(TagValue << Shift),
+ static_cast<uint8_t>(NoAliasMask << Shift), NoAliasNode};
}
bool areHighBitsZExtd(uint8_t BitsFrom) const {
@@ -222,6 +254,9 @@ class Pointer {
// The address of the pointer. The bit width is determined by
// DataLayout::getPointerSizeInBits.
APInt Address;
+ // A side-channel id for the noalias borrow tree node this pointer is based
+ // on. This is intentionally separate from the pointer provenance above.
+ uint64_t NoAliasNode = 0;
public:
explicit Pointer(const APInt &Address)
@@ -230,17 +265,27 @@ class Pointer {
: Prov(std::move(Prov)), Address(Address) {
assert(this->Prov && "Invalid provenance.");
}
+ explicit Pointer(IntrusiveRefCntPtr<Provenance> Prov, const APInt &Address,
+ uint64_t NoAliasNode)
+ : Prov(std::move(Prov)), Address(Address), NoAliasNode(NoAliasNode) {
+ assert(this->Prov && "Invalid provenance.");
+ }
Pointer getWithNewAddr(const APInt &NewAddr) const {
- return Pointer(Prov, NewAddr);
+ return Pointer(Prov, NewAddr, NoAliasNode);
}
Pointer getWithNewProvenance(IntrusiveRefCntPtr<Provenance> NewProv) const {
- return Pointer(NewProv, Address);
+ return Pointer(NewProv, Address, NoAliasNode);
+ }
+ Pointer getWithNoAliasNode(uint64_t NewNoAliasNode) const {
+ return Pointer(Prov, Address, NewNoAliasNode);
}
static AnyValue null(unsigned AS, const DataLayout &DL);
bool isNullPtr(unsigned AS, const DataLayout &DL) const;
void print(raw_ostream &OS) const;
const APInt &address() const { return Address; }
Provenance &provenance() const { return *Prov; }
+ MemoryObject *getMemoryObject() const { return Prov->getMemoryObject(); }
+ uint64_t getNoAliasNodeID() const { return NoAliasNode; }
};
/// Represents a scalar byte value. If the value is not byte-sized, the high
diff --git a/llvm/tools/llubi/llubi.cpp b/llvm/tools/llubi/llubi.cpp
index 00863dd5ecb391..6a628c9a79beb1 100644
--- a/llvm/tools/llubi/llubi.cpp
+++ b/llvm/tools/llubi/llubi.cpp
@@ -85,6 +85,11 @@ static cl::opt<bool>
cl::desc("Disable interpreter-introduced non-determinism."),
cl::init(false), cl::cat(InterpreterCategory));
+static cl::opt<bool>
+ ExperimentalNoAlias("experimental-noalias",
+ cl::desc("Enable experimental LLVM noalias checking."),
+ cl::init(false), cl::cat(InterpreterCategory));
+
static cl::opt<bool> FuseFMulAdd("fuse-fmuladd",
cl::desc("Fuse llvm.fmuladd.* intrinsic"),
cl::init(true), cl::cat(InterpreterCategory));
@@ -196,6 +201,10 @@ class VerboseEventHandler : public NoopEventHandler {
llvm_unreachable("Unknown ProgramExitKind");
}
+ bool onNoAliasEvent(StringRef Msg) override {
+ errs() << "NoAlias: " << Msg << '\n';
+ return true;
+ }
};
int main(int argc, char **argv) {
@@ -258,6 +267,7 @@ int main(int argc, char **argv) {
Ctx.setMaxStackDepth(MaxStackDepth);
Ctx.setFusedMultiplyAdd(FuseFMulAdd);
Ctx.setDeterministic(Deterministic);
+ Ctx.setExperimentalNoAlias(ExperimentalNoAlias);
Ctx.setUndefValueBehavior(UndefBehavior);
Ctx.setNaNPropagationBehavior(NaNPropagationBehavior);
Ctx.reseed(Seed);
>From a138514c521b2195cd8f9ab89b3a6fe9ea92cdaa Mon Sep 17 00:00:00 2001
From: Zhige Chen <zhigec_cpp at outlook.com>
Date: Tue, 5 May 2026 16:30:59 +0800
Subject: [PATCH 2/5] [llubi] Fix Pointer::getWithNewAddr
---
.../test/tools/llubi/noalias_outside_range.ll | 24 ++++++++----------
.../tools/llubi/noalias_overlapping_ranges.ll | 25 +++++++------------
2 files changed, 19 insertions(+), 30 deletions(-)
diff --git a/llvm/test/tools/llubi/noalias_outside_range.ll b/llvm/test/tools/llubi/noalias_outside_range.ll
index aa946d0f11e84a..173a9aaa4c2596 100644
--- a/llvm/test/tools/llubi/noalias_outside_range.ll
+++ b/llvm/test/tools/llubi/noalias_outside_range.ll
@@ -36,21 +36,17 @@ define void @main() {
; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [1, 2) checked 1 active noalias protector
; CHECK-NEXT: store i8 42, ptr %raw1, align 1
; CHECK-NEXT: %x2 = getelementptr i8, ptr %x, i64 2 => ptr 0xA [data + 2]
-; CHECK-NEXT: NoAlias: node #1 foreign read through raw/root on 'data' bytes [2, 3): Reserved -> ReservedF
-; CHECK-NEXT: NoAlias: read through raw/root on 'data' bytes [2, 3) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: node #1 local read through node #1 on 'data' bytes [2, 3): Reserved -> ReservedL
+; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [2, 3) checked 1 active noalias protector
; CHECK-NEXT: %v2 = load i8, ptr %x2, align 1 => i8 62
; CHECK-NEXT: %x3 = getelementptr i8, ptr %x, i64 3 => ptr 0xB [data + 3]
-; CHECK-NEXT: NoAlias: node #1 foreign read through raw/root on 'data' bytes [3, 4): Reserved -> ReservedF
-; CHECK-NEXT: NoAlias: read through raw/root on 'data' bytes [3, 4) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: node #1 local read through node #1 on 'data' bytes [3, 4): Reserved -> ReservedL
+; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [3, 4) checked 1 active noalias protector
; CHECK-NEXT: %v3 = load i8, ptr %x3, align 1 => i8 -117
; CHECK-NEXT: %raw3 = getelementptr i8, ptr %raw, i64 3 => ptr 0xB [data + 3]
-; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'data' bytes [3, 4): ReservedF -> Disabled
-; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [3, 4) checked 1 active noalias protector
-; CHECK-NEXT: store i8 42, ptr %raw3, align 1
-; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: ended protector node #1
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: Exiting function: stuff
-; CHECK-NEXT: call void @stuff(ptr %raw, ptr %raw)
-; CHECK-NEXT: ret void
-; CHECK-NEXT: Exiting function: main
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'data' bytes [3, 4) is foreign to protected node #1, but that protector is in ReservedL state
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i8 42, ptr %raw3, align 1 at @stuff
+; CHECK-NEXT: #1 call void @stuff(ptr %raw, ptr %raw) at @main
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'data' bytes [3, 4) is foreign to protected node #1, but that protector is in ReservedL state
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_overlapping_ranges.ll b/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
index 068e4a9136ee90..c9e4d8815fb629 100644
--- a/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
+++ b/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
@@ -26,21 +26,14 @@ define void @main() {
; CHECK-NEXT: NoAlias: created protector node #1 for 'array' based on raw/root
; CHECK-NEXT: NoAlias: created protector node #2 for 'array' based on raw/root
; CHECK-NEXT: %a1 = getelementptr [4 x i32], ptr %a, i64 0, i64 1 => ptr 0xC [array + 4]
-; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'array' bytes [4, 8): Reserved -> Disabled
-; CHECK-NEXT: NoAlias: node #2 foreign write through raw/root on 'array' bytes [4, 8): Reserved -> Disabled
-; CHECK-NEXT: NoAlias: write through raw/root on 'array' bytes [4, 8) checked 2 active noalias protectors
+; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'array' bytes [4, 8): Reserved -> Unique
+; CHECK-NEXT: NoAlias: node #2 foreign write through node #1 on 'array' bytes [4, 8): Reserved -> Disabled
+; CHECK-NEXT: NoAlias: write through node #1 on 'array' bytes [4, 8) checked 2 active noalias protectors
; CHECK-NEXT: store i32 5, ptr %a1, align 4
; CHECK-NEXT: %b1 = getelementptr [4 x i32], ptr %b, i64 0, i64 1 => ptr 0xC [array + 4]
-; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'array' bytes [4, 8): Disabled -> Disabled
-; CHECK-NEXT: NoAlias: node #2 foreign write through raw/root on 'array' bytes [4, 8): Disabled -> Disabled
-; CHECK-NEXT: NoAlias: write through raw/root on 'array' bytes [4, 8) checked 2 active noalias protectors
-; CHECK-NEXT: store i32 6, ptr %b1, align 4
-; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: ended protector node #1
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: ended protector node #2
-; CHECK-NEXT: NoAlias: erased inactive protector node #2
-; CHECK-NEXT: Exiting function: write_overlap
-; CHECK-NEXT: call void @write_overlap(ptr %array, ptr %array)
-; CHECK-NEXT: ret void
-; CHECK-NEXT: Exiting function: main
+; CHECK-NEXT: NoAlias: noalias violation: write through node #2 on 'array' bytes [4, 8) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i32 6, ptr %b1, align 4 at @write_overlap
+; CHECK-NEXT: #1 call void @write_overlap(ptr %array, ptr %array) at @main
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #2 on 'array' bytes [4, 8) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: error: Execution of function 'main' failed.
>From 744a309636431844508a39a73194a592dc39f147 Mon Sep 17 00:00:00 2001
From: Zhige Chen <zhigec_cpp at outlook.com>
Date: Mon, 20 Jul 2026 14:36:54 +0800
Subject: [PATCH 3/5] [llubi] Refactor noalias implementation
---
llvm/test/tools/llubi/noalias_after_return.ll | 10 +-
.../tools/llubi/noalias_aliasing_reads.ll | 22 +-
.../tools/llubi/noalias_disjoint_intervals.ll | 22 +-
.../tools/llubi/noalias_foreign_access.ll | 14 +-
.../tools/llubi/noalias_nested_activations.ll | 73 +++
.../test/tools/llubi/noalias_outside_range.ll | 22 +-
.../tools/llubi/noalias_overlapping_ranges.ll | 17 +-
.../tools/llubi/noalias_prune_stale_node.ll | 14 +-
.../llubi/noalias_reserved_foreign_read.ll | 14 +-
llvm/tools/llubi/lib/Context.cpp | 427 ++++++++----------
llvm/tools/llubi/lib/Context.h | 98 ++--
llvm/tools/llubi/lib/ExecutorBase.cpp | 11 +-
llvm/tools/llubi/lib/ExecutorBase.h | 4 +-
llvm/tools/llubi/lib/Interpreter.cpp | 8 +-
14 files changed, 361 insertions(+), 395 deletions(-)
create mode 100644 llvm/test/tools/llubi/noalias_nested_activations.ll
diff --git a/llvm/test/tools/llubi/noalias_after_return.ll b/llvm/test/tools/llubi/noalias_after_return.ll
index 6738a951b53c6f..0ad633eddf420d 100644
--- a/llvm/test/tools/llubi/noalias_after_return.ll
+++ b/llvm/test/tools/llubi/noalias_after_return.ll
@@ -18,15 +18,13 @@ define void @main() {
; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
; CHECK-NEXT: Entering function: write_one
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'a' bytes [0, 4): Reserved -> Unique
-; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: store i32 1, ptr %x, align 4
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: protector end for node #1 triggers synthetic write on 'a' bytes [0, 4)
-; CHECK-NEXT: NoAlias: protector end: node #1 local write through node #1 on 'a' bytes [0, 4): Unique -> Unique
-; CHECK-NEXT: NoAlias: ended protector node #1
; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: write_one
; CHECK-NEXT: call void @write_one(ptr %a)
; CHECK-NEXT: %v = load i32, ptr %a, align 4 => i32 1
diff --git a/llvm/test/tools/llubi/noalias_aliasing_reads.ll b/llvm/test/tools/llubi/noalias_aliasing_reads.ll
index c1fcd813c0211c..ab80f0ade27b68 100644
--- a/llvm/test/tools/llubi/noalias_aliasing_reads.ll
+++ b/llvm/test/tools/llubi/noalias_aliasing_reads.ll
@@ -20,26 +20,18 @@ define void @main() {
; CHECK-NEXT: Entering function: read_both
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
; CHECK-NEXT: ptr %y = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: created protector node #2 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: node #1 local read through node #1 on 'a' bytes [0, 4): Reserved -> ReservedL
-; CHECK-NEXT: NoAlias: node #2 foreign read through node #1 on 'a' bytes [0, 4): Reserved -> ReservedF
-; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 2 active noalias protectors
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 4): unaccessed -> reads by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: %vx = load i32, ptr %x, align 4 => i32 42
-; CHECK-NEXT: NoAlias: node #1 foreign read through node #2 on 'a' bytes [0, 4): ReservedL -> ReservedLF
-; CHECK-NEXT: NoAlias: node #2 local read through node #2 on 'a' bytes [0, 4): ReservedF -> ReservedLF
-; CHECK-NEXT: NoAlias: read through node #2 on 'a' bytes [0, 4) checked 2 active noalias protectors
+; CHECK-NEXT: NoAlias: activation #1 read through node #2 on 'a' bytes [0, 4): reads by node #1 -> reads by multiple access classes
+; CHECK-NEXT: NoAlias: read through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: %vy = load i32, ptr %y, align 4 => i32 42
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: protector end for node #1 triggers synthetic read on 'a' bytes [0, 4)
-; CHECK-NEXT: NoAlias: protector end: node #1 local read through node #1 on 'a' bytes [0, 4): ReservedLF -> ReservedLF
-; CHECK-NEXT: NoAlias: protector end: node #2 foreign read through node #1 on 'a' bytes [0, 4): ReservedLF -> ReservedLF
-; CHECK-NEXT: NoAlias: ended protector node #1
; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: protector end for node #2 triggers synthetic read on 'a' bytes [0, 4)
-; CHECK-NEXT: NoAlias: protector end: node #2 local read through node #2 on 'a' bytes [0, 4): ReservedLF -> ReservedLF
-; CHECK-NEXT: NoAlias: ended protector node #2
; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: read_both
; CHECK-NEXT: call void @read_both(ptr %a, ptr %a)
; CHECK-NEXT: ret void
diff --git a/llvm/test/tools/llubi/noalias_disjoint_intervals.ll b/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
index dd9030e9ea10f6..e328b7919e1869 100644
--- a/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
+++ b/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
@@ -22,26 +22,18 @@ define void @main() {
; CHECK-NEXT: Entering function: write_disjoint
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
; CHECK-NEXT: ptr %y = ptr 0xC [a + 4]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: created protector node #2 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'a' bytes [0, 4): Reserved -> Unique
-; CHECK-NEXT: NoAlias: node #2 foreign write through node #1 on 'a' bytes [0, 4): Reserved -> Disabled
-; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 2 active noalias protectors
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: store i32 1, ptr %x, align 4
-; CHECK-NEXT: NoAlias: node #1 foreign write through node #2 on 'a' bytes [4, 8): Reserved -> Disabled
-; CHECK-NEXT: NoAlias: node #2 local write through node #2 on 'a' bytes [4, 8): Reserved -> Unique
-; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [4, 8) checked 2 active noalias protectors
+; CHECK-NEXT: NoAlias: activation #1 write through node #2 on 'a' bytes [4, 8): unaccessed -> access including a write by node #2
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [4, 8) checked 1 active noalias activation
; CHECK-NEXT: store i32 2, ptr %y, align 4
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: protector end for node #1 triggers synthetic write on 'a' bytes [0, 4)
-; CHECK-NEXT: NoAlias: protector end: node #1 local write through node #1 on 'a' bytes [0, 4): Unique -> Unique
-; CHECK-NEXT: NoAlias: protector end: node #2 foreign write through node #1 on 'a' bytes [0, 4): Disabled -> Disabled
-; CHECK-NEXT: NoAlias: ended protector node #1
; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: protector end for node #2 triggers synthetic write on 'a' bytes [4, 8)
-; CHECK-NEXT: NoAlias: protector end: node #2 local write through node #2 on 'a' bytes [4, 8): Unique -> Unique
-; CHECK-NEXT: NoAlias: ended protector node #2
; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: write_disjoint
; CHECK-NEXT: call void @write_disjoint(ptr %x, ptr %y)
; CHECK-NEXT: %v = load [2 x i32], ptr %a, align 4 => { i32 1, i32 2 }
diff --git a/llvm/test/tools/llubi/noalias_foreign_access.ll b/llvm/test/tools/llubi/noalias_foreign_access.ll
index b76effb09d746c..927a43f9dcc498 100644
--- a/llvm/test/tools/llubi/noalias_foreign_access.ll
+++ b/llvm/test/tools/llubi/noalias_foreign_access.ll
@@ -20,13 +20,13 @@ define void @main() {
; CHECK-NEXT: Entering function: violates
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
; CHECK-NEXT: ptr %y = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'a' bytes [0, 4): Reserved -> Unique
-; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: store i32 1, ptr %x, align 4
-; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: Stacktrace:
-; CHECK-NEXT: #0 %v = load i32, ptr %y, align 4 at @violates
-; CHECK-NEXT: #1 call void @violates(ptr %a, ptr %a) at @main
-; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: #0 %v = load i32, ptr %y, align 4 at @violates <stdin>:6
+; CHECK-NEXT: #1 call void @violates(ptr %a, ptr %a) at @main <stdin>:13
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_nested_activations.ll b/llvm/test/tools/llubi/noalias_nested_activations.ll
new file mode 100644
index 00000000000000..1cd8cff29b6737
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_nested_activations.ll
@@ -0,0 +1,73 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+define void @write_inner(ptr noalias %x) {
+ store i32 1, ptr %x
+ ret void
+}
+
+define void @outer_ok(ptr noalias %x) {
+ store i32 0, ptr %x
+ call void @write_inner(ptr %x)
+ %v = load i32, ptr %x
+ ret void
+}
+
+define void @outer_bad(ptr noalias %x, ptr %raw) {
+ store i32 0, ptr %x
+ call void @write_inner(ptr %raw)
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @outer_ok(ptr %a)
+ call void @outer_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: outer_ok
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 0, ptr %x, align 4
+; CHECK-NEXT: Entering function: write_inner
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on node #1
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: activation #2 write through node #2 on 'a' bytes [0, 4): unaccessed -> access including a write by node #2
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 2 active noalias activations
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: Exiting function: write_inner
+; CHECK-NEXT: call void @write_inner(ptr %x)
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: %v = load i32, ptr %x, align 4 => i32 1
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: outer_ok
+; CHECK-NEXT: call void @outer_ok(ptr %a)
+; CHECK-NEXT: Entering function: outer_bad
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #3 for 'a' in activation #3 based on raw/root
+; CHECK-NEXT: NoAlias: activation #3 write through node #3 on 'a' bytes [0, 4): unaccessed -> access including a write by node #3
+; CHECK-NEXT: NoAlias: write through node #3 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 0, ptr %x, align 4
+; CHECK-NEXT: Entering function: write_inner
+; CHECK-NEXT: ptr %x = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #4 for 'a' in activation #4 based on raw/root
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #3
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i32 1, ptr %x, align 4 at @write_inner <stdin>:5
+; CHECK-NEXT: #1 call void @write_inner(ptr %raw) at @outer_bad <stdin>:18
+; CHECK-NEXT: #2 call void @outer_bad(ptr %a, ptr %a) at @main <stdin>:25
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #3
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_outside_range.ll b/llvm/test/tools/llubi/noalias_outside_range.ll
index 173a9aaa4c2596..0db9d92ad235da 100644
--- a/llvm/test/tools/llubi/noalias_outside_range.ll
+++ b/llvm/test/tools/llubi/noalias_outside_range.ll
@@ -30,23 +30,23 @@ define void @main() {
; CHECK-NEXT: Entering function: stuff
; CHECK-NEXT: ptr %x = ptr 0x8 [data]
; CHECK-NEXT: ptr %raw = ptr 0x8 [data]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'data' based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #1 for 'data' in activation #1 based on raw/root
; CHECK-NEXT: %raw1 = getelementptr i8, ptr %raw, i64 1 => ptr 0x9 [data + 1]
-; CHECK-NEXT: NoAlias: node #1 foreign write through raw/root on 'data' bytes [1, 2): Reserved -> Disabled
-; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [1, 2) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: activation #1 write through raw/root on 'data' bytes [1, 2): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [1, 2) checked 1 active noalias activation
; CHECK-NEXT: store i8 42, ptr %raw1, align 1
; CHECK-NEXT: %x2 = getelementptr i8, ptr %x, i64 2 => ptr 0xA [data + 2]
-; CHECK-NEXT: NoAlias: node #1 local read through node #1 on 'data' bytes [2, 3): Reserved -> ReservedL
-; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [2, 3) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'data' bytes [2, 3): unaccessed -> reads by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [2, 3) checked 1 active noalias activation
; CHECK-NEXT: %v2 = load i8, ptr %x2, align 1 => i8 62
; CHECK-NEXT: %x3 = getelementptr i8, ptr %x, i64 3 => ptr 0xB [data + 3]
-; CHECK-NEXT: NoAlias: node #1 local read through node #1 on 'data' bytes [3, 4): Reserved -> ReservedL
-; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [3, 4) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'data' bytes [3, 4): unaccessed -> reads by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [3, 4) checked 1 active noalias activation
; CHECK-NEXT: %v3 = load i8, ptr %x3, align 1 => i8 -117
; CHECK-NEXT: %raw3 = getelementptr i8, ptr %raw, i64 3 => ptr 0xB [data + 3]
-; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'data' bytes [3, 4) is foreign to protected node #1, but that protector is in ReservedL state
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'data' bytes [3, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: Stacktrace:
-; CHECK-NEXT: #0 store i8 42, ptr %raw3, align 1 at @stuff
-; CHECK-NEXT: #1 call void @stuff(ptr %raw, ptr %raw) at @main
-; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'data' bytes [3, 4) is foreign to protected node #1, but that protector is in ReservedL state
+; CHECK-NEXT: #0 store i8 42, ptr %raw3, align 1 at @stuff <stdin>:16
+; CHECK-NEXT: #1 call void @stuff(ptr %raw, ptr %raw) at @main <stdin>:23
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'data' bytes [3, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_overlapping_ranges.ll b/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
index c9e4d8815fb629..511fd8d6eae32e 100644
--- a/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
+++ b/llvm/test/tools/llubi/noalias_overlapping_ranges.ll
@@ -23,17 +23,16 @@ define void @main() {
; CHECK-NEXT: Entering function: write_overlap
; CHECK-NEXT: ptr %a = ptr 0x8 [array]
; CHECK-NEXT: ptr %b = ptr 0x8 [array]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'array' based on raw/root
-; CHECK-NEXT: NoAlias: created protector node #2 for 'array' based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #1 for 'array' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'array' in activation #1 based on raw/root
; CHECK-NEXT: %a1 = getelementptr [4 x i32], ptr %a, i64 0, i64 1 => ptr 0xC [array + 4]
-; CHECK-NEXT: NoAlias: node #1 local write through node #1 on 'array' bytes [4, 8): Reserved -> Unique
-; CHECK-NEXT: NoAlias: node #2 foreign write through node #1 on 'array' bytes [4, 8): Reserved -> Disabled
-; CHECK-NEXT: NoAlias: write through node #1 on 'array' bytes [4, 8) checked 2 active noalias protectors
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'array' bytes [4, 8): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'array' bytes [4, 8) checked 1 active noalias activation
; CHECK-NEXT: store i32 5, ptr %a1, align 4
; CHECK-NEXT: %b1 = getelementptr [4 x i32], ptr %b, i64 0, i64 1 => ptr 0xC [array + 4]
-; CHECK-NEXT: NoAlias: noalias violation: write through node #2 on 'array' bytes [4, 8) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: NoAlias: noalias violation: write through node #2 on 'array' bytes [4, 8) combines multiple access classes with a write in activation #1
; CHECK-NEXT: Stacktrace:
-; CHECK-NEXT: #0 store i32 6, ptr %b1, align 4 at @write_overlap
-; CHECK-NEXT: #1 call void @write_overlap(ptr %array, ptr %array) at @main
-; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #2 on 'array' bytes [4, 8) is foreign to protected node #1, but that protector is in Unique state
+; CHECK-NEXT: #0 store i32 6, ptr %b1, align 4 at @write_overlap <stdin>:11
+; CHECK-NEXT: #1 call void @write_overlap(ptr %array, ptr %array) at @main <stdin>:17
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #2 on 'array' bytes [4, 8) combines multiple access classes with a write in activation #1
; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_prune_stale_node.ll b/llvm/test/tools/llubi/noalias_prune_stale_node.ll
index da83ef7d01659f..1d91bd9022b90c 100644
--- a/llvm/test/tools/llubi/noalias_prune_stale_node.ll
+++ b/llvm/test/tools/llubi/noalias_prune_stale_node.ll
@@ -26,25 +26,23 @@ define void @main() {
; CHECK-NEXT: Entering function: capture
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
; CHECK-NEXT: ptr %slot = ptr 0x10 [slot]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
; CHECK-NEXT: store ptr %x, ptr %slot, align 8
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: ended protector node #1
; CHECK-NEXT: NoAlias: erased inactive protector node #1
+; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: capture
; CHECK-NEXT: call void @capture(ptr %a, ptr %slot)
; CHECK-NEXT: %stale = load ptr, ptr %slot, align 8 => ptr 0x8 [a]
; CHECK-NEXT: Entering function: write_one
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #2 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: node #2 local write through node #2 on 'a' bytes [0, 4): Reserved -> Unique
-; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: activation #2 write through node #2 on 'a' bytes [0, 4): unaccessed -> access including a write by node #2
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: store i32 1, ptr %x, align 4
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: protector end for node #2 triggers synthetic write on 'a' bytes [0, 4)
-; CHECK-NEXT: NoAlias: protector end: node #2 local write through node #2 on 'a' bytes [0, 4): Unique -> Unique
-; CHECK-NEXT: NoAlias: ended protector node #2
; CHECK-NEXT: NoAlias: erased inactive protector node #2
+; CHECK-NEXT: NoAlias: ended activation #2
; CHECK-NEXT: Exiting function: write_one
; CHECK-NEXT: call void @write_one(ptr %stale)
; CHECK-NEXT: ret void
diff --git a/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll b/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll
index 671659b1759f79..71309741953a3d 100644
--- a/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll
+++ b/llvm/test/tools/llubi/noalias_reserved_foreign_read.ll
@@ -23,13 +23,13 @@ define void @main() {
; CHECK-NEXT: Entering function: foreign_read_then_local_write
; CHECK-NEXT: ptr %x = ptr 0x8 [a]
; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' based on raw/root
-; CHECK-NEXT: NoAlias: node #1 foreign read through raw/root on 'a' bytes [0, 4): Reserved -> ReservedF
-; CHECK-NEXT: NoAlias: read through raw/root on 'a' bytes [0, 4) checked 1 active noalias protector
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 read through raw/root on 'a' bytes [0, 4): unaccessed -> reads by raw/root
+; CHECK-NEXT: NoAlias: read through raw/root on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: %v = load i32, ptr %raw, align 4 => i32 0
-; CHECK-NEXT: NoAlias: noalias violation: write through node #1 on 'a' bytes [0, 4) is local to protected node #1, but that protector is in ReservedF state
+; CHECK-NEXT: NoAlias: noalias violation: write through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: Stacktrace:
-; CHECK-NEXT: #0 store i32 1, ptr %x, align 4 at @foreign_read_then_local_write
-; CHECK-NEXT: #1 call void @foreign_read_then_local_write(ptr %a, ptr %a) at @main
-; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #1 on 'a' bytes [0, 4) is local to protected node #1, but that protector is in ReservedF state
+; CHECK-NEXT: #0 store i32 1, ptr %x, align 4 at @foreign_read_then_local_write <stdin>:9
+; CHECK-NEXT: #1 call void @foreign_read_then_local_write(ptr %a, ptr %a) at @main <stdin>:16
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/tools/llubi/lib/Context.cpp b/llvm/tools/llubi/lib/Context.cpp
index d723665f2b7eb0..6aec7e413068f3 100644
--- a/llvm/tools/llubi/lib/Context.cpp
+++ b/llvm/tools/llubi/lib/Context.cpp
@@ -1430,26 +1430,6 @@ StringRef Context::getNoAliasAccessKindName(NoAliasAccessKind Kind) {
llvm_unreachable("Unknown NoAliasAccessKind");
}
-StringRef Context::getNoAliasStateName(NoAliasState State) {
- switch (State) {
- case NoAliasState::Reserved:
- return "Reserved";
- case NoAliasState::ReservedL:
- return "ReservedL";
- case NoAliasState::ReservedF:
- return "ReservedF";
- case NoAliasState::ReservedLF:
- return "ReservedLF";
- case NoAliasState::Unique:
- return "Unique";
- case NoAliasState::Disabled:
- return "Disabled";
- case NoAliasState::Dummy:
- return "Dummy";
- }
- llvm_unreachable("Unknown NoAliasState");
-}
-
std::string Context::getNoAliasNodeName(uint64_t NodeID) {
if (!NodeID)
return "raw/root";
@@ -1459,6 +1439,13 @@ std::string Context::getNoAliasNodeName(uint64_t NodeID) {
return S;
}
+std::string Context::getNoAliasActivationName(uint64_t ActivationID) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "activation #" << ActivationID;
+ return S;
+}
+
std::string Context::getNoAliasObjectName(const MemoryObject &MO) {
if (MO.getName().empty()) {
std::string S;
@@ -1474,222 +1461,172 @@ void Context::appendNoAliasEvent(std::string Msg) {
NoAliasEvents.push_back(std::move(Msg));
}
-void Context::setNoAliasViolation(uint64_t ProtectedNodeId, uint64_t AccessNode,
- const MemoryObject &MO, uint64_t Begin,
- uint64_t End, NoAliasAccessKind Kind,
- bool IsLocal, NoAliasState State,
- bool IsProtectorEndAction) {
- std::string S;
- raw_string_ostream OS(S);
- OS << "noalias ";
- if (IsProtectorEndAction)
- OS << "protector end ";
- OS << "violation: " << getNoAliasAccessKindName(Kind) << " through "
- << getNoAliasNodeName(AccessNode) << " on " << getNoAliasObjectName(MO)
- << " bytes [" << Begin << ", " << End << ") is "
- << (IsLocal ? "local" : "foreign") << " to protected "
- << getNoAliasNodeName(ProtectedNodeId) << ", but that protector is in "
- << getNoAliasStateName(State) << " state";
- LastNoAliasError = std::move(S);
- appendNoAliasEvent(LastNoAliasError);
-}
-
-std::optional<Context::NoAliasState>
-Context::transitionNoAliasState(NoAliasState State, NoAliasAccessKind Kind,
- bool IsLocal) {
- if (State == NoAliasState::Dummy)
- return NoAliasState::Dummy;
-
- // For the complete state machine, please refer to the original blog
- // https://jhostert.de/blog/2025/noalias/.
- const bool IsWrite = Kind == NoAliasAccessKind::Write;
- switch (State) {
- case NoAliasState::Reserved: {
- if (!IsWrite)
- return IsLocal ? NoAliasState::ReservedL : NoAliasState::ReservedF;
- return IsLocal ? NoAliasState::Unique : NoAliasState::Disabled;
- }
- case NoAliasState::ReservedL: {
- if (IsLocal)
- return IsWrite ? NoAliasState::Unique : NoAliasState::ReservedL;
- if (!IsWrite)
- return NoAliasState::ReservedLF;
- return std::nullopt;
- }
- case NoAliasState::ReservedF: {
- if (!IsLocal)
- return IsWrite ? NoAliasState::Disabled : NoAliasState::ReservedF;
- if (!IsWrite)
- return NoAliasState::ReservedLF;
- return std::nullopt;
- }
- case NoAliasState::ReservedLF: {
- if (!IsWrite)
- return NoAliasState::ReservedLF;
- return std::nullopt;
- }
- case NoAliasState::Unique: {
- if (IsLocal)
- return NoAliasState::Unique;
- return std::nullopt;
- }
- case NoAliasState::Disabled: {
- if (!IsLocal)
- return NoAliasState::Disabled;
- return std::nullopt;
- }
- case NoAliasState::Dummy:
- llvm_unreachable("Dummy state should be handled earlier");
- }
- llvm_unreachable("Unknown NoAliasState");
-}
-
-bool Context::accessNoAliasImpl(MemoryObject &MO, uint64_t Offset,
- uint64_t Size, uint64_t AccessNode,
- NoAliasAccessKind Kind,
- uint64_t SkipDescendantsOf) {
- if (!ActiveNoAliasScopes || !Size)
- return true;
-
- const auto It = NoAliasNodesByObject.find(&MO);
- if (It == NoAliasNodesByObject.end())
- return true;
-
- const uint64_t End = Offset + Size;
- uint32_t CheckedNodes = 0;
- for (uint64_t NodeID : It->second) {
- auto NodeIt = NoAliasNodes.find(NodeID);
- if (NodeIt == NoAliasNodes.end() || !NodeIt->second.Active)
- continue;
- if (SkipDescendantsOf && NodeID != SkipDescendantsOf &&
- isNoAliasAncestor(SkipDescendantsOf, NodeID))
+uint64_t Context::classifyNoAliasAccess(const NoAliasActivation &Activation,
+ const MemoryObject &MO,
+ uint64_t AccessNode) const {
+ for (uint64_t NodeID : Activation.Nodes) {
+ const auto It = NoAliasNodes.find(NodeID);
+ if (It == NoAliasNodes.end() || !It->second.Active ||
+ It->second.Object != &MO)
continue;
- ++CheckedNodes;
- // A protected node judges the same concrete memory access differently
- // depending on whether the pointer used for the access is in its subtree.
- if (const bool IsLocal = isNoAliasAncestor(NodeID, AccessNode);
- !updateNoAliasNodeForAccess(
- NodeIt->second, Offset, End, Kind, IsLocal, NodeID, AccessNode,
- /*IsProtectorEndAction=*/SkipDescendantsOf != 0))
- return false;
- }
- if (CheckedNodes && !SkipDescendantsOf) {
- std::string S;
- raw_string_ostream OS(S);
- OS << getNoAliasAccessKindName(Kind) << " through "
- << getNoAliasNodeName(AccessNode) << " on " << getNoAliasObjectName(MO)
- << " bytes [" << Offset << ", " << End << ") checked " << CheckedNodes
- << " active noalias protector" << (CheckedNodes == 1 ? "" : "s");
- appendNoAliasEvent(std::move(S));
+ if (isNoAliasAncestor(NodeID, AccessNode))
+ return NodeID;
}
- return true;
+ return 0;
}
-bool Context::updateNoAliasNodeForAccess(NoAliasNode &Node, uint64_t Begin,
- uint64_t End, NoAliasAccessKind Kind,
- bool IsLocal, uint64_t ProtectedNodeID,
- uint64_t AccessNode,
- bool IsProtectorEndAction) {
+bool Context::updateNoAliasAccesses(NoAliasActivation &Activation,
+ MemoryObject &MO, uint64_t Begin,
+ uint64_t End, uint64_t AccessClass,
+ NoAliasAccessKind Kind,
+ uint64_t ActivationID) {
assert(Begin < End && "empty accesses should not reach noalias tracking");
- SmallVector<NoAliasStateRun, 4> NewRuns;
- auto AppendRun = [&](uint64_t RunBegin, uint64_t RunEnd, NoAliasState State) {
- if (RunBegin == RunEnd || State == NoAliasState::Reserved)
+ SmallVector<NoAliasAccessRun, 4> NewRuns;
+ auto AppendRun = [&](uint64_t RunBegin, uint64_t RunEnd,
+ NoAliasAccessSummary Summary) {
+ if (RunBegin == RunEnd)
return;
if (!NewRuns.empty() && NewRuns.back().End == RunBegin &&
- NewRuns.back().State == State) {
+ NewRuns.back().Summary == Summary) {
NewRuns.back().End = RunEnd;
return;
}
- NewRuns.push_back({RunBegin, RunEnd, State});
+ NewRuns.push_back({RunBegin, RunEnd, Summary});
+ };
+
+ auto DescribeSummary = [&](raw_ostream &OS,
+ const NoAliasAccessSummary &Summary) {
+ if (Summary.MultipleClasses) {
+ OS << "reads by multiple access classes";
+ return;
+ }
+ OS << (Summary.HasWrite ? "access including a write by " : "reads by ")
+ << getNoAliasNodeName(Summary.AccessClass);
};
auto AppendTransitioned = [&](uint64_t RunBegin, uint64_t RunEnd,
- NoAliasState State) -> bool {
+ const NoAliasAccessSummary *Old) -> bool {
if (RunBegin == RunEnd)
return true;
- std::optional<NoAliasState> NewState =
- transitionNoAliasState(State, Kind, IsLocal);
- if (!NewState) {
- setNoAliasViolation(ProtectedNodeID, AccessNode, *Node.Object, RunBegin,
- RunEnd, Kind, IsLocal, State, IsProtectorEndAction);
+
+ const bool IsWrite = Kind == NoAliasAccessKind::Write;
+ NoAliasAccessSummary New{AccessClass, false, IsWrite};
+ if (Old) {
+ New = *Old;
+ if (Old->MultipleClasses) {
+ if (IsWrite)
+ New.HasWrite = true;
+ } else if (Old->AccessClass == AccessClass) {
+ New.HasWrite |= IsWrite;
+ } else if (Old->HasWrite || IsWrite) {
+ New.MultipleClasses = true;
+ New.HasWrite = true;
+ } else {
+ New.AccessClass = 0;
+ New.MultipleClasses = true;
+ }
+ }
+
+ if (New.MultipleClasses && New.HasWrite) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << "noalias violation: " << getNoAliasAccessKindName(Kind)
+ << " through " << getNoAliasNodeName(AccessClass) << " on "
+ << getNoAliasObjectName(MO) << " bytes [" << RunBegin << ", " << RunEnd
+ << ") combines multiple access classes with a write in "
+ << getNoAliasActivationName(ActivationID);
+ LastNoAliasError = std::move(S);
+ appendNoAliasEvent(LastNoAliasError);
return false;
}
+
std::string S;
raw_string_ostream OS(S);
- if (IsProtectorEndAction)
- OS << "protector end: ";
- OS << getNoAliasNodeName(ProtectedNodeID) << ' '
- << (IsLocal ? "local" : "foreign") << ' '
+ OS << getNoAliasActivationName(ActivationID) << ' '
<< getNoAliasAccessKindName(Kind) << " through "
- << getNoAliasNodeName(AccessNode) << " on "
- << getNoAliasObjectName(*Node.Object) << " bytes [" << RunBegin << ", "
- << RunEnd << "): " << getNoAliasStateName(State) << " -> "
- << getNoAliasStateName(*NewState);
+ << getNoAliasNodeName(AccessClass) << " on " << getNoAliasObjectName(MO)
+ << " bytes [" << RunBegin << ", " << RunEnd << "): ";
+ if (Old)
+ DescribeSummary(OS, *Old);
+ else
+ OS << "unaccessed";
+ OS << " -> ";
+ DescribeSummary(OS, New);
appendNoAliasEvent(std::move(S));
- AppendRun(RunBegin, RunEnd, *NewState);
+ AppendRun(RunBegin, RunEnd, New);
return true;
};
+ auto &Runs = Activation.Accesses[&MO];
uint64_t Cur = Begin;
bool InsertedAccessTail = false;
- for (const NoAliasStateRun &Run : Node.States) {
+ for (const NoAliasAccessRun &Run : Runs) {
if (Run.End <= Begin) {
- AppendRun(Run.Begin, Run.End, Run.State);
+ AppendRun(Run.Begin, Run.End, Run.Summary);
continue;
}
if (Run.Begin >= End) {
if (!InsertedAccessTail) {
- // The access ends before this run begins, so [Cur, End) is an implicit
- // Reserved gap that still needs transition.
- if (!AppendTransitioned(Cur, End, NoAliasState::Reserved))
+ if (!AppendTransitioned(Cur, End, nullptr))
return false;
InsertedAccessTail = true;
}
- AppendRun(Run.Begin, Run.End, Run.State);
+ AppendRun(Run.Begin, Run.End, Run.Summary);
continue;
}
if (Run.Begin < Begin)
- AppendRun(Run.Begin, Begin, Run.State);
+ AppendRun(Run.Begin, Begin, Run.Summary);
const uint64_t OverlapBegin = std::max(Cur, Run.Begin);
- // Any gap between the previous covered byte and this run is also implicit
- // Reserved state.
- if (!AppendTransitioned(Cur, OverlapBegin, NoAliasState::Reserved))
+ if (!AppendTransitioned(Cur, OverlapBegin, nullptr))
return false;
const uint64_t OverlapEnd = std::min(End, Run.End);
- if (!AppendTransitioned(OverlapBegin, OverlapEnd, Run.State))
+ if (!AppendTransitioned(OverlapBegin, OverlapEnd, &Run.Summary))
return false;
Cur = OverlapEnd;
if (Run.End > End) {
- AppendRun(End, Run.End, Run.State);
+ AppendRun(End, Run.End, Run.Summary);
InsertedAccessTail = true;
}
}
if (!InsertedAccessTail) {
- if (!AppendTransitioned(Cur, End, NoAliasState::Reserved))
+ if (!AppendTransitioned(Cur, End, nullptr))
return false;
}
- Node.States = std::move(NewRuns);
+ Runs = std::move(NewRuns);
return true;
}
-Pointer Context::createNoAliasPointer(const Pointer &Ptr) {
+uint64_t Context::beginNoAliasActivation() {
if (!ExperimentalNoAlias)
+ return 0;
+ const uint64_t ActivationID = NextNoAliasActivation++;
+ NoAliasActivations.try_emplace(ActivationID);
+ return ActivationID;
+}
+
+Pointer Context::createNoAliasPointer(const Pointer &Ptr,
+ uint64_t ActivationID) {
+ if (!ExperimentalNoAlias || !ActivationID)
return Ptr;
MemoryObject *MO = Ptr.getMemoryObject();
if (!MO)
return Ptr;
+ auto ActivationIt = NoAliasActivations.find(ActivationID);
+ assert(ActivationIt != NoAliasActivations.end() &&
+ "Noalias activation must be live before creating a parameter node.");
+
const uint64_t NodeID = NextNoAliasNode++;
uint64_t Parent = Ptr.getNoAliasNodeID();
- // If the parent node was pruned after its protector ended, the incoming
- // pointer is treated as a raw/root-derived pointer for this new scope.
+ // If the parent node was pruned after its activation ended, the incoming
+ // pointer is treated as a raw/root-derived pointer for this new activation.
if (Parent && NoAliasNodes.find(Parent) == NoAliasNodes.end())
Parent = 0;
NoAliasNode Node;
@@ -1697,92 +1634,86 @@ Pointer Context::createNoAliasPointer(const Pointer &Ptr) {
Node.Object = MO;
Node.Active = true;
NoAliasNodes.try_emplace(NodeID, std::move(Node));
- NoAliasNodesByObject[MO].push_back(NodeID);
- ++ActiveNoAliasScopes;
+ ActivationIt->second.Nodes.push_back(NodeID);
+
+ auto &Activations = NoAliasActivationsByObject[MO];
+ if (std::find(Activations.begin(), Activations.end(), ActivationID) ==
+ Activations.end())
+ Activations.push_back(ActivationID);
+
std::string S;
raw_string_ostream OS(S);
OS << "created protector " << getNoAliasNodeName(NodeID) << " for "
- << getNoAliasObjectName(*MO) << " based on " << getNoAliasNodeName(Parent);
+ << getNoAliasObjectName(*MO) << " in "
+ << getNoAliasActivationName(ActivationID) << " based on "
+ << getNoAliasNodeName(Parent);
appendNoAliasEvent(std::move(S));
return Ptr.getWithNoAliasNode(NodeID);
}
bool Context::accessNoAlias(MemoryObject &MO, uint64_t Offset, uint64_t Size,
uint64_t AccessNode, NoAliasAccessKind Kind) {
- if (!ExperimentalNoAlias)
+ if (!ExperimentalNoAlias || !Size)
+ return true;
+
+ auto It = NoAliasActivationsByObject.find(&MO);
+ if (It == NoAliasActivationsByObject.end())
return true;
- return accessNoAliasImpl(MO, Offset, Size, AccessNode, Kind,
- /*SkipDescendantsOf=*/0);
+ const uint64_t End = Offset + Size;
+ uint32_t CheckedActivations = 0;
+ for (uint64_t ActivationID : It->second) {
+ auto ActivationIt = NoAliasActivations.find(ActivationID);
+ if (ActivationIt == NoAliasActivations.end())
+ continue;
+ ++CheckedActivations;
+ const uint64_t AccessClass =
+ classifyNoAliasAccess(ActivationIt->second, MO, AccessNode);
+ if (!updateNoAliasAccesses(ActivationIt->second, MO, Offset, End,
+ AccessClass, Kind, ActivationID))
+ return false;
+ }
+
+ if (CheckedActivations) {
+ std::string S;
+ raw_string_ostream OS(S);
+ OS << getNoAliasAccessKindName(Kind) << " through "
+ << getNoAliasNodeName(AccessNode) << " on " << getNoAliasObjectName(MO)
+ << " bytes [" << Offset << ", " << End << ") checked "
+ << CheckedActivations << " active noalias activation"
+ << (CheckedActivations == 1 ? "" : "s");
+ appendNoAliasEvent(std::move(S));
+ }
+ return true;
}
-bool Context::endNoAliasScopes(ArrayRef<uint64_t> Nodes) {
+void Context::endNoAliasActivation(uint64_t ActivationID) {
if (!ExperimentalNoAlias)
- return true;
+ return;
+
+ auto ActivationIt = NoAliasActivations.find(ActivationID);
+ if (ActivationIt == NoAliasActivations.end())
+ return;
+ SmallVector<uint64_t, 4> Nodes(ActivationIt->second.Nodes.begin(),
+ ActivationIt->second.Nodes.end());
for (uint64_t NodeID : Nodes) {
- auto It = NoAliasNodes.find(NodeID);
- if (It == NoAliasNodes.end() || !It->second.Active)
+ auto NodeIt = NoAliasNodes.find(NodeID);
+ if (NodeIt == NoAliasNodes.end())
continue;
-
- SmallVector<NoAliasStateRun, 4> States(It->second.States.begin(),
- It->second.States.end());
- for (const NoAliasStateRun &Run : States) {
- std::optional<NoAliasAccessKind> EndAction;
- // Protector end actions. Quote from the original blog:
- // "Unique triggers writes, ReservedL and ReservedLF triggers reads, and
- // the other states trigger nothing since they have not yet been locally
- // accessed. Like in Tree Borrows, these end actions are “special” in
- // that they don’t affect children of the node which was protected."
- switch (Run.State) {
- case NoAliasState::Unique:
- EndAction = NoAliasAccessKind::Write;
- break;
- case NoAliasState::ReservedL:
- case NoAliasState::ReservedLF:
- EndAction = NoAliasAccessKind::Read;
- break;
- case NoAliasState::Reserved:
- case NoAliasState::ReservedF:
- case NoAliasState::Disabled:
- case NoAliasState::Dummy:
- break;
- }
- if (EndAction) {
- std::string S;
- raw_string_ostream OS(S);
- OS << "protector end for " << getNoAliasNodeName(NodeID)
- << " triggers synthetic " << getNoAliasAccessKindName(*EndAction)
- << " on " << getNoAliasObjectName(*It->second.Object) << " bytes ["
- << Run.Begin << ", " << Run.End << ")";
- appendNoAliasEvent(std::move(S));
- if (!accessNoAliasImpl(*It->second.Object, Run.Begin,
- Run.End - Run.Begin, NodeID, *EndAction,
- /*SkipDescendantsOf=*/NodeID))
- return false;
- }
- }
-
- It->second.Active = false;
- It->second.States.clear();
- // Remove inactive nodes from the per-object active list immediately, but
- // keep the node record itself until no active child depends on its parent
- // identity.
- if (auto ObjIt = NoAliasNodesByObject.find(It->second.Object);
- ObjIt != NoAliasNodesByObject.end()) {
- SmallVectorImpl<uint64_t> &ObjectNodes = ObjIt->second;
- ObjectNodes.erase(
- std::remove(ObjectNodes.begin(), ObjectNodes.end(), NodeID),
- ObjectNodes.end());
- if (ObjectNodes.empty())
- NoAliasNodesByObject.erase(ObjIt);
- }
- assert(ActiveNoAliasScopes && "mismatched noalias protector count");
- --ActiveNoAliasScopes;
- appendNoAliasEvent("ended protector " + getNoAliasNodeName(NodeID));
+ MemoryObject *MO = NodeIt->second.Object;
+ NodeIt->second.Active = false;
tryEraseInactiveNoAliasNode(NodeID);
+ auto ObjectIt = NoAliasActivationsByObject.find(MO);
+ if (ObjectIt == NoAliasActivationsByObject.end())
+ continue;
+ auto &IDs = ObjectIt->second;
+ IDs.erase(std::remove(IDs.begin(), IDs.end(), ActivationID), IDs.end());
+ if (IDs.empty())
+ NoAliasActivationsByObject.erase(ObjectIt);
}
- return true;
+ appendNoAliasEvent("ended " + getNoAliasActivationName(ActivationID));
+ NoAliasActivations.erase(ActivationIt);
}
SmallVector<std::string, 4> Context::takeNoAliasEvents() {
@@ -1795,19 +1726,23 @@ void Context::clearNoAliasState(const MemoryObject &MO) {
if (!ExperimentalNoAlias)
return;
- const auto It = NoAliasNodesByObject.find(&MO);
- if (It == NoAliasNodesByObject.end())
+ const auto It = NoAliasActivationsByObject.find(&MO);
+ if (It == NoAliasActivationsByObject.end())
return;
- for (uint64_t NodeID : It->second) {
- auto NodeIt = NoAliasNodes.find(NodeID);
- if (NodeIt == NoAliasNodes.end() || !NodeIt->second.Active)
+ SmallVector<uint64_t, 4> ActivationIDs(It->second.begin(), It->second.end());
+ for (uint64_t ActivationID : ActivationIDs) {
+ auto ActivationIt = NoAliasActivations.find(ActivationID);
+ if (ActivationIt == NoAliasActivations.end())
continue;
- NodeIt->second.Active = false;
- NodeIt->second.States.clear();
- assert(ActiveNoAliasScopes && "mismatched noalias protector count");
- --ActiveNoAliasScopes;
+ for (uint64_t NodeID : ActivationIt->second.Nodes) {
+ auto NodeIt = NoAliasNodes.find(NodeID);
+ if (NodeIt != NoAliasNodes.end() && NodeIt->second.Object == &MO)
+ NodeIt->second.Active = false;
+ tryEraseInactiveNoAliasNode(NodeID);
+ }
+ ActivationIt->second.Accesses.erase(const_cast<MemoryObject *>(&MO));
}
- NoAliasNodesByObject.erase(It);
+ NoAliasActivationsByObject.erase(It);
}
} // namespace llvm::ubi
diff --git a/llvm/tools/llubi/lib/Context.h b/llvm/tools/llubi/lib/Context.h
index a8d968f5ca4eb0..d4195402f75f36 100644
--- a/llvm/tools/llubi/lib/Context.h
+++ b/llvm/tools/llubi/lib/Context.h
@@ -297,43 +297,47 @@ class Context {
/// Get the tag for the given pointer provenance.
APInt getTag(uint32_t BitWidth, Provenance &Prov);
- /// Experimental noalias states (see https://jhostert.de/blog/2025/noalias/).
- /// The states Frozen and FrozenL from the original state machine are omitted
- /// as proposed. Note that the Reserved state is the implicit default and is
- /// intentionally omitted from sparse state runs below.
- enum class NoAliasState : uint8_t {
- Reserved,
- ReservedL,
- ReservedF,
- ReservedLF,
- Unique,
- Disabled,
- Dummy,
+ /// Summary of the access classes that touched a byte range during one
+ /// dynamic function activation. Multiple access classes are permitted only
+ /// while every access is a read.
+ struct NoAliasAccessSummary {
+ uint64_t AccessClass = 0;
+ bool MultipleClasses = false;
+ bool HasWrite = false;
+
+ bool operator==(const NoAliasAccessSummary &Other) const {
+ return AccessClass == Other.AccessClass &&
+ MultipleClasses == Other.MultipleClasses &&
+ HasWrite == Other.HasWrite;
+ }
};
- /// A non-Reserved state over the byte interval [Begin, End).
- struct NoAliasStateRun {
+ struct NoAliasAccessRun {
uint64_t Begin;
uint64_t End;
- NoAliasState State;
+ NoAliasAccessSummary Summary;
};
- /// A protected noalias node created by retagging a noalias function argument.
- /// Parent is another noalias node, or 0 for the raw/root parent. The
- /// underlying pointer provenance remains represented by Pointer::Obj.
+ /// A noalias access class created by retagging a function argument. Parent is
+ /// another node, or 0 for the raw/root parent. Nodes carry no memory state;
+ /// they are used only to classify accesses in active function activations.
struct NoAliasNode {
uint64_t Parent = 0;
MemoryObject *Object = nullptr;
bool Active = false;
- // Run-Length Encoding to reduce memory consumption.
- SmallVector<NoAliasStateRun, 1> States;
};
- // The node ID 0 is reserved for raw/root nodes.
+ struct NoAliasActivation {
+ SmallVector<uint64_t, 4> Nodes;
+ DenseMap<MemoryObject *, SmallVector<NoAliasAccessRun, 1>> Accesses;
+ };
+
+ // ID 0 is reserved for the raw/root access class and for no activation.
uint64_t NextNoAliasNode = 1;
- uint64_t ActiveNoAliasScopes = 0;
+ uint64_t NextNoAliasActivation = 1;
DenseMap<uint64_t, NoAliasNode> NoAliasNodes;
- DenseMap<MemoryObject *, SmallVector<uint64_t, 2>> NoAliasNodesByObject;
+ DenseMap<uint64_t, NoAliasActivation> NoAliasActivations;
+ DenseMap<MemoryObject *, SmallVector<uint64_t, 2>> NoAliasActivationsByObject;
// noalias-related diagnostics
std::string LastNoAliasError;
@@ -359,36 +363,16 @@ class Context {
/// Try to erase the node if it is inactive and has no active descendant.
void tryEraseInactiveNoAliasNode(uint64_t NodeID);
static StringRef getNoAliasAccessKindName(NoAliasAccessKind Kind);
- static StringRef getNoAliasStateName(NoAliasState State);
static std::string getNoAliasNodeName(uint64_t NodeID);
+ static std::string getNoAliasActivationName(uint64_t ActivationID);
static std::string getNoAliasObjectName(const MemoryObject &MO);
void appendNoAliasEvent(std::string Msg);
- /// Record a noalias violation in both the user-facing error slot and verbose
- /// event queue.
- void setNoAliasViolation(uint64_t ProtectedNodeId, uint64_t AccessNode,
- const MemoryObject &MO, uint64_t Begin, uint64_t End,
- NoAliasAccessKind Kind, bool IsLocal,
- NoAliasState State, bool IsProtectorEndAction);
- /// Apply the noalias state machine for one homogeneous byte range. Returns
- /// std::nullopt when the access is forbidden and should be reported as an
- /// immediate UB.
- static std::optional<NoAliasState>
- transitionNoAliasState(NoAliasState State, NoAliasAccessKind Kind,
- bool IsLocal);
- /// Apply a memory access to every active protector for \p MO. \p
- /// SkipDescendantsOf is used for protector-end synthetic accesses.
- bool accessNoAliasImpl(MemoryObject &MO, uint64_t Offset, uint64_t Size,
- uint64_t AccessNode, NoAliasAccessKind Kind,
- uint64_t SkipDescendantsOf);
- /// Update one node's sparse byte-state runs for access to [Begin, End).
- /// The nodes store only non-Reserved runs, so this routine splits old runs,
- /// treats gaps as implicit Reserved ranges, transitions each touches segment,
- /// and coalesces adjacent ranges that end in the same non-Reserved state.
- bool updateNoAliasNodeForAccess(NoAliasNode &Node, uint64_t Begin,
- uint64_t End, NoAliasAccessKind Kind,
- bool IsLocal, uint64_t ProtectedNodeID,
- uint64_t AccessNode,
- bool IsProtectorEndAction);
+ uint64_t classifyNoAliasAccess(const NoAliasActivation &Activation,
+ const MemoryObject &MO,
+ uint64_t AccessNode) const;
+ bool updateNoAliasAccesses(NoAliasActivation &Activation, MemoryObject &MO,
+ uint64_t Begin, uint64_t End, uint64_t AccessClass,
+ NoAliasAccessKind Kind, uint64_t ActivationID);
// Constants
// Use std::map to avoid iterator/reference invalidation.
@@ -526,15 +510,15 @@ class Context {
Function *getTargetFunction(const Pointer &Ptr);
BasicBlock *getTargetBlock(const Pointer &Ptr);
- /// Create a new protected noalias node based on \p Ptr and return a pointer
- /// associated with that node. The underlying pointer provenance is unchanged.
- Pointer createNoAliasPointer(const Pointer &Ptr);
- /// Apply a memory access to the active noalias state machines for \p MO.
- /// Returns false when the protected state machine detects UB.
+ /// Begin one dynamic function activation containing noalias parameters.
+ uint64_t beginNoAliasActivation();
+ /// Create an access class for a noalias parameter in \p ActivationID.
+ Pointer createNoAliasPointer(const Pointer &Ptr, uint64_t ActivationID);
+ /// Apply an access to every active activation protecting \p MO.
bool accessNoAlias(MemoryObject &MO, uint64_t Offset, uint64_t Size,
uint64_t AccessNode, NoAliasAccessKind Kind);
- /// End all noalias protectors created for a call frame.
- bool endNoAliasScopes(ArrayRef<uint64_t> Nodes);
+ /// End an activation and discard its access summaries.
+ void endNoAliasActivation(uint64_t ActivationID);
StringRef getLastNoAliasError() const { return LastNoAliasError; }
SmallVector<std::string, 4> takeNoAliasEvents();
/// Drop noalias state for an object \p MO that is no longer usable.
diff --git a/llvm/tools/llubi/lib/ExecutorBase.cpp b/llvm/tools/llubi/lib/ExecutorBase.cpp
index 5bc53de09362a3..fc634830aa0892 100644
--- a/llvm/tools/llubi/lib/ExecutorBase.cpp
+++ b/llvm/tools/llubi/lib/ExecutorBase.cpp
@@ -28,11 +28,12 @@ Frame::Frame(Context &Ctx, Function &F, CallBase *CallSite, Frame *LastFrame,
// protected node for the dynamic call frame without changing the normal
// provenance carried by the pointer.
if (Ctx.isExperimentalNoAliasEnabled() && Arg.hasNoAliasAttr() &&
- Arg.getType()->isPointerTy() && !ArgValue.isPoison()) {
- Pointer Retagged = Ctx.createNoAliasPointer(ArgValue.asPointer());
- if (uint64_t NodeID = Retagged.getNoAliasNodeID())
- NoAliasNodes.push_back(NodeID);
- ArgValue = Retagged;
+ Arg.getType()->isPointerTy() && !ArgValue.isPoison() &&
+ ArgValue.asPointer().getMemoryObject()) {
+ if (!NoAliasActivation)
+ NoAliasActivation = Ctx.beginNoAliasActivation();
+ ArgValue =
+ Ctx.createNoAliasPointer(ArgValue.asPointer(), NoAliasActivation);
}
ValueMap[&Arg] = std::move(ArgValue);
}
diff --git a/llvm/tools/llubi/lib/ExecutorBase.h b/llvm/tools/llubi/lib/ExecutorBase.h
index 815ee7b5700fc4..370808d77814b0 100644
--- a/llvm/tools/llubi/lib/ExecutorBase.h
+++ b/llvm/tools/llubi/lib/ExecutorBase.h
@@ -58,8 +58,8 @@ struct Frame {
// Stack objects allocated in this frame. They will be automatically freed
// when the function returns.
SmallVector<IntrusiveRefCntPtr<MemoryObject>> Allocas;
- // Protected noalias nodes created for this frame's arguments
- SmallVector<uint64_t, 4> NoAliasNodes;
+ // Dynamic noalias activation shared by this frame's noalias parameters.
+ uint64_t NoAliasActivation = 0;
// Values of arguments and executed instructions in this function.
DenseMap<Value *, AnyValue> ValueMap;
diff --git a/llvm/tools/llubi/lib/Interpreter.cpp b/llvm/tools/llubi/lib/Interpreter.cpp
index c159fea539b162..e15f4f0b197e4a 100644
--- a/llvm/tools/llubi/lib/Interpreter.cpp
+++ b/llvm/tools/llubi/lib/Interpreter.cpp
@@ -2872,13 +2872,7 @@ class InstExecutor : public InstVisitor<InstExecutor, void>,
if (Top.State == FrameState::Exit) {
assert((Top.Func.getReturnType()->isVoidTy() || !Top.RetVal.isNone()) &&
"Expected return value to be set on function exit.");
- // End protectors before freeing frame allocas: protector end actions
- // are still accesses to the protected memory object.
- if (!Ctx.endNoAliasScopes(Top.NoAliasNodes)) {
- flushNoAliasEvents();
- reportImmediateUB() << Ctx.getLastNoAliasError();
- break;
- }
+ Ctx.endNoAliasActivation(Top.NoAliasActivation);
flushNoAliasEvents();
Handler.onFunctionExit(Top.Func, Top.RetVal);
// Free stack objects allocated in this frame.
>From f14cda8259e927e92b0840f46fc9b51f20c9b320 Mon Sep 17 00:00:00 2001
From: Zhige Chen <zhigec_cpp at outlook.com>
Date: Sat, 26 Sep 2026 14:45:10 +0800
Subject: [PATCH 4/5] [llubi] Refine noalias semantic and add more tests.
---
llvm/test/tools/llubi/noalias_after_return.ll | 33 -----
.../test/tools/llubi/noalias_aliasing_mut1.ll | 40 ++++++
.../test/tools/llubi/noalias_aliasing_mut2.ll | 39 ++++++
.../tools/llubi/noalias_aliasing_reads.ll | 2 -
.../tools/llubi/noalias_aliasing_unused.ll | 60 ++++++++
llvm/test/tools/llubi/noalias_byval.ll | 34 +++++
llvm/test/tools/llubi/noalias_callsite.ll | 32 +++++
.../tools/llubi/noalias_callsite_indirect.ll | 34 +++++
.../tools/llubi/noalias_callsite_intrinsic.ll | 25 ++++
.../tools/llubi/noalias_disjoint_intervals.ll | 2 -
.../tools/llubi/noalias_escaped_pointer.ll | 84 +++++++++++
llvm/test/tools/llubi/noalias_free.ll | 35 +++++
llvm/test/tools/llubi/noalias_histogram.ll | 33 +++++
llvm/test/tools/llubi/noalias_libc_read.ll | 32 +++++
llvm/test/tools/llubi/noalias_memcpy.ll | 39 ++++++
.../tools/llubi/noalias_memcpy_destination.ll | 43 ++++++
llvm/test/tools/llubi/noalias_memmove.ll | 36 +++++
.../llubi/noalias_memory_effects_valid.ll | 131 ++++++++++++++++++
llvm/test/tools/llubi/noalias_memset.ll | 34 +++++
.../test/tools/llubi/noalias_memset_inline.ll | 34 +++++
.../tools/llubi/noalias_nested_activations.ll | 2 -
.../test/tools/llubi/noalias_outside_range.ll | 8 +-
.../noalias_outside_range_foreign_first.ll | 40 ++++++
.../llubi/noalias_outside_range_unused.ll | 50 +++++++
.../tools/llubi/noalias_prune_stale_node.ll | 49 -------
.../tools/llubi/noalias_returned_pointer.ll | 64 +++++++++
...noalias_returned_pointer_foreign_access.ll | 44 ++++++
llvm/test/tools/llubi/noalias_wildcard.ll | 36 +++++
.../llubi/noalias_wildcard_foreign_first.ll | 36 +++++
.../noalias_wildcard_outside_allocation.ll | 40 ++++++
.../tools/llubi/noalias_wildcard_valid.ll | 69 +++++++++
llvm/tools/llubi/lib/Context.cpp | 94 +++++--------
llvm/tools/llubi/lib/Context.h | 11 +-
llvm/tools/llubi/lib/ExecutorBase.cpp | 76 +++++-----
llvm/tools/llubi/lib/ExecutorBase.h | 16 ++-
llvm/tools/llubi/lib/Interpreter.cpp | 11 ++
llvm/tools/llubi/lib/Library.cpp | 4 +
37 files changed, 1261 insertions(+), 191 deletions(-)
delete mode 100644 llvm/test/tools/llubi/noalias_after_return.ll
create mode 100644 llvm/test/tools/llubi/noalias_aliasing_mut1.ll
create mode 100644 llvm/test/tools/llubi/noalias_aliasing_mut2.ll
create mode 100644 llvm/test/tools/llubi/noalias_aliasing_unused.ll
create mode 100644 llvm/test/tools/llubi/noalias_byval.ll
create mode 100644 llvm/test/tools/llubi/noalias_callsite.ll
create mode 100644 llvm/test/tools/llubi/noalias_callsite_indirect.ll
create mode 100644 llvm/test/tools/llubi/noalias_callsite_intrinsic.ll
create mode 100644 llvm/test/tools/llubi/noalias_escaped_pointer.ll
create mode 100644 llvm/test/tools/llubi/noalias_free.ll
create mode 100644 llvm/test/tools/llubi/noalias_histogram.ll
create mode 100644 llvm/test/tools/llubi/noalias_libc_read.ll
create mode 100644 llvm/test/tools/llubi/noalias_memcpy.ll
create mode 100644 llvm/test/tools/llubi/noalias_memcpy_destination.ll
create mode 100644 llvm/test/tools/llubi/noalias_memmove.ll
create mode 100644 llvm/test/tools/llubi/noalias_memory_effects_valid.ll
create mode 100644 llvm/test/tools/llubi/noalias_memset.ll
create mode 100644 llvm/test/tools/llubi/noalias_memset_inline.ll
create mode 100644 llvm/test/tools/llubi/noalias_outside_range_foreign_first.ll
create mode 100644 llvm/test/tools/llubi/noalias_outside_range_unused.ll
delete mode 100644 llvm/test/tools/llubi/noalias_prune_stale_node.ll
create mode 100644 llvm/test/tools/llubi/noalias_returned_pointer.ll
create mode 100644 llvm/test/tools/llubi/noalias_returned_pointer_foreign_access.ll
create mode 100644 llvm/test/tools/llubi/noalias_wildcard.ll
create mode 100644 llvm/test/tools/llubi/noalias_wildcard_foreign_first.ll
create mode 100644 llvm/test/tools/llubi/noalias_wildcard_outside_allocation.ll
create mode 100644 llvm/test/tools/llubi/noalias_wildcard_valid.ll
diff --git a/llvm/test/tools/llubi/noalias_after_return.ll b/llvm/test/tools/llubi/noalias_after_return.ll
deleted file mode 100644
index 0ad633eddf420d..00000000000000
--- a/llvm/test/tools/llubi/noalias_after_return.ll
+++ /dev/null
@@ -1,33 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
-; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
-
-define void @write_one(ptr noalias %x) {
- store i32 1, ptr %x
- ret void
-}
-
-define void @main() {
- %a = alloca i32
- call void @write_one(ptr %a)
- %v = load i32, ptr %a
- store i32 2, ptr %a
- ret void
-}
-
-; CHECK: Entering function: main
-; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
-; CHECK-NEXT: Entering function: write_one
-; CHECK-NEXT: ptr %x = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
-; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
-; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
-; CHECK-NEXT: store i32 1, ptr %x, align 4
-; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: ended activation #1
-; CHECK-NEXT: Exiting function: write_one
-; CHECK-NEXT: call void @write_one(ptr %a)
-; CHECK-NEXT: %v = load i32, ptr %a, align 4 => i32 1
-; CHECK-NEXT: store i32 2, ptr %a, align 4
-; CHECK-NEXT: ret void
-; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_aliasing_mut1.ll b/llvm/test/tools/llubi/noalias_aliasing_mut1.ll
new file mode 100644
index 00000000000000..6de7199ea2421e
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_aliasing_mut1.ll
@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Adapted from Miri's tests/fail/both_borrows/aliasing_mut1.rs.
+; An indirect call with no call-site attributes must still create distinct
+; noalias tags for the callee's two parameters, even for identical arguments.
+; Unlike Rust reference retagging, noalias does not implicitly read either
+; argument: the first store succeeds, and the second store must fail.
+
+define void @write_both(ptr noalias %x, ptr noalias %y) {
+ store i32 1, ptr %x
+ store i32 2, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ %fn = select i1 true, ptr @write_both, ptr null
+ call void %fn(ptr %a, ptr %a)
+ ret void
+}
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0xC [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: %fn = select i1 true, ptr @write_both, ptr null => ptr 0x8 [@write_both]
+; CHECK-NEXT: Entering function: write_both
+; CHECK-NEXT: ptr %x = ptr 0xC [a]
+; CHECK-NEXT: ptr %y = ptr 0xC [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: NoAlias: noalias violation: write through node #2 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i32 2, ptr %y, align 4 at @write_both <stdin>:12
+; CHECK-NEXT: #1 call void %fn(ptr %a, ptr %a) at @main <stdin>:20
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #2 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_aliasing_mut2.ll b/llvm/test/tools/llubi/noalias_aliasing_mut2.ll
new file mode 100644
index 00000000000000..70adf8e88ffeae
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_aliasing_mut2.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Adapted from Miri's tests/fail/both_borrows/aliasing_mut2.rs.
+; Both arguments carry only noalias. The indirect call has no call-site
+; attributes. The explicit read through one argument makes the later write
+; through its sibling UB.
+
+define void @read_write(ptr noalias %x, ptr noalias %y) {
+ %v = load i32, ptr %x
+ store i32 2, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ %fn = select i1 true, ptr @read_write, ptr null
+ call void %fn(ptr %a, ptr %a)
+ ret void
+}
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0xC [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: %fn = select i1 true, ptr @read_write, ptr null => ptr 0x8 [@read_write]
+; CHECK-NEXT: Entering function: read_write
+; CHECK-NEXT: ptr %x = ptr 0xC [a]
+; CHECK-NEXT: ptr %y = ptr 0xC [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 4): unaccessed -> reads by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: %v = load i32, ptr %x, align 4 => i32 0
+; CHECK-NEXT: NoAlias: noalias violation: write through node #2 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i32 2, ptr %y, align 4 at @read_write <stdin>:11
+; CHECK-NEXT: #1 call void %fn(ptr %a, ptr %a) at @main <stdin>:19
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #2 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_aliasing_reads.ll b/llvm/test/tools/llubi/noalias_aliasing_reads.ll
index ab80f0ade27b68..9c2f886f6999d5 100644
--- a/llvm/test/tools/llubi/noalias_aliasing_reads.ll
+++ b/llvm/test/tools/llubi/noalias_aliasing_reads.ll
@@ -29,8 +29,6 @@ define void @main() {
; CHECK-NEXT: NoAlias: read through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: %vy = load i32, ptr %y, align 4 => i32 42
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: erased inactive protector node #2
; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: read_both
; CHECK-NEXT: call void @read_both(ptr %a, ptr %a)
diff --git a/llvm/test/tools/llubi/noalias_aliasing_unused.ll b/llvm/test/tools/llubi/noalias_aliasing_unused.ll
new file mode 100644
index 00000000000000..a6174c9d5a8c10
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_aliasing_unused.ll
@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Variants of Miri's tests/fail/both_borrows/aliasing_mut{1,2}.rs with one
+; argument unused. LLVM noalias does not perform Rust's implicit retag reads,
+; so identical arguments are allowed when only one is accessed, regardless
+; of argument order. Protector removal must also succeed.
+
+define void @write_first(ptr noalias %x, ptr noalias %y) {
+ store i32 1, ptr %x
+ ret void
+}
+
+define void @write_second(ptr noalias %x, ptr noalias %y) {
+ store i32 2, ptr %y
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ %first = select i1 true, ptr @write_first, ptr null
+ call void %first(ptr %a, ptr %a)
+ %second = select i1 true, ptr @write_second, ptr null
+ call void %second(ptr %a, ptr %a)
+ %v = load i32, ptr %a
+ ret void
+}
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0xC [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: %first = select i1 true, ptr @write_first, ptr null => ptr 0x8 [@write_first]
+; CHECK-NEXT: Entering function: write_first
+; CHECK-NEXT: ptr %x = ptr 0xC [a]
+; CHECK-NEXT: ptr %y = ptr 0xC [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %x, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: write_first
+; CHECK-NEXT: call void %first(ptr %a, ptr %a)
+; CHECK-NEXT: %second = select i1 true, ptr @write_second, ptr null => ptr 0xA [@write_second]
+; CHECK-NEXT: Entering function: write_second
+; CHECK-NEXT: ptr %x = ptr 0xC [a]
+; CHECK-NEXT: ptr %y = ptr 0xC [a]
+; CHECK-NEXT: NoAlias: created protector node #3 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #4 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: activation #2 write through node #4 on 'a' bytes [0, 4): unaccessed -> access including a write by node #4
+; CHECK-NEXT: NoAlias: write through node #4 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 2, ptr %y, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: Exiting function: write_second
+; CHECK-NEXT: call void %second(ptr %a, ptr %a)
+; CHECK-NEXT: %v = load i32, ptr %a, align 4 => i32 2
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_byval.ll b/llvm/test/tools/llubi/noalias_byval.ll
new file mode 100644
index 00000000000000..fadf0fe15c0806
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_byval.ll
@@ -0,0 +1,34 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; The implicit byval copy reads through the original argument.
+
+define void @sink(ptr byval(i32) %p) {
+ ret void
+}
+define void @outer(ptr noalias %p, ptr %raw) {
+ store i32 1, ptr %p
+ call void @sink(ptr byval(i32) %raw)
+ ret void
+}
+define void @main() {
+ %a = alloca i32
+ call void @outer(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: outer
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @sink(ptr byval(i32) %raw) at @outer <stdin>:11
+; CHECK-NEXT: #1 call void @outer(ptr %a, ptr %a) at @main <stdin>:16
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_callsite.ll b/llvm/test/tools/llubi/noalias_callsite.ll
new file mode 100644
index 00000000000000..aeef510cb072c0
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_callsite.ll
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A call-site-only noalias guarantee applies to this invocation.
+
+define void @plain_write_read(ptr %p, ptr %q) {
+ store i32 1, ptr %p
+ %v = load i32, ptr %q
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @plain_write_read(ptr noalias %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: plain_write_read
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %q = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i32, ptr %q, align 4 at @plain_write_read <stdin>:8
+; CHECK-NEXT: #1 call void @plain_write_read(ptr noalias %a, ptr %a) at @main <stdin>:14
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_callsite_indirect.ll b/llvm/test/tools/llubi/noalias_callsite_indirect.ll
new file mode 100644
index 00000000000000..bf367e7ec1c0ee
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_callsite_indirect.ll
@@ -0,0 +1,34 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A call-site-only noalias guarantee applies to this invocation.
+
+define void @plain_write_read(ptr %p, ptr %q) {
+ store i32 1, ptr %p
+ %v = load i32, ptr %q
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ %fn = select i1 true, ptr @plain_write_read, ptr null
+ call void %fn(ptr noalias %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0xC [a]
+; CHECK-NEXT: %fn = select i1 true, ptr @plain_write_read, ptr null => ptr 0x8 [@plain_write_read]
+; CHECK-NEXT: Entering function: plain_write_read
+; CHECK-NEXT: ptr %p = ptr 0xC [a]
+; CHECK-NEXT: ptr %q = ptr 0xC [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i32, ptr %q, align 4 at @plain_write_read <stdin>:8
+; CHECK-NEXT: #1 call void %fn(ptr noalias %a, ptr %a) at @main <stdin>:15
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_callsite_intrinsic.ll b/llvm/test/tools/llubi/noalias_callsite_intrinsic.ll
new file mode 100644
index 00000000000000..11f8ab9c7e4e7d
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_callsite_intrinsic.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Call-site noalias also applies to calls without an interpreter frame.
+
+declare void @llvm.memmove.p0.p0.i64(ptr, ptr, i64, i1)
+define void @main() {
+ %a = alloca i32
+ store i32 0, ptr %a
+ call void @llvm.memmove.p0.p0.i64(ptr noalias %a, ptr %a, i64 4, i1 false)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: store i32 0, ptr %a, align 4
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 read through raw/root on 'a' bytes [0, 4): unaccessed -> reads by raw/root
+; CHECK-NEXT: NoAlias: read through raw/root on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: NoAlias: noalias violation: write through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.memmove.p0.p0.i64(ptr noalias %a, ptr %a, i64 4, i1 false) at @main <stdin>:10
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_disjoint_intervals.ll b/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
index e328b7919e1869..cd2e1fbb2377bc 100644
--- a/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
+++ b/llvm/test/tools/llubi/noalias_disjoint_intervals.ll
@@ -31,8 +31,6 @@ define void @main() {
; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [4, 8) checked 1 active noalias activation
; CHECK-NEXT: store i32 2, ptr %y, align 4
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: erased inactive protector node #2
; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: write_disjoint
; CHECK-NEXT: call void @write_disjoint(ptr %x, ptr %y)
diff --git a/llvm/test/tools/llubi/noalias_escaped_pointer.ll b/llvm/test/tools/llubi/noalias_escaped_pointer.ll
new file mode 100644
index 00000000000000..5b2e10a8401c89
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_escaped_pointer.ll
@@ -0,0 +1,84 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Storing and reloading an inner noalias pointer preserves outer ancestry.
+
+define void @capture(ptr noalias %p, ptr %slot) {
+ store ptr %p, ptr %slot
+ ret void
+}
+
+define void @write_one(ptr noalias %p) {
+ store i32 3, ptr %p
+ ret void
+}
+
+define void @escaped_outer(ptr noalias %p) {
+ %slot = alloca ptr
+ call void @capture(ptr %p, ptr %slot)
+ %q = load ptr, ptr %slot
+ store i32 1, ptr %p
+ store i32 2, ptr %q
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @escaped_outer(ptr %a)
+ ; Retagging an escaped pointer also works after all protectors have ended.
+ %slot = alloca ptr
+ call void @capture(ptr %a, ptr %slot)
+ %stale = load ptr, ptr %slot
+ call void @write_one(ptr %stale)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: escaped_outer
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: %slot = alloca ptr, align 8 => ptr 0x10 [slot]
+; CHECK-NEXT: Entering function: capture
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %slot = ptr 0x10 [slot]
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on node #1
+; CHECK-NEXT: store ptr %p, ptr %slot, align 8
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: Exiting function: capture
+; CHECK-NEXT: call void @capture(ptr %p, ptr %slot)
+; CHECK-NEXT: %q = load ptr, ptr %slot, align 8 => ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 2, ptr %q, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: escaped_outer
+; CHECK-NEXT: call void @escaped_outer(ptr %a)
+; CHECK-NEXT: %slot = alloca ptr, align 8 => ptr 0x20 [slot]
+; CHECK-NEXT: Entering function: capture
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %slot = ptr 0x20 [slot]
+; CHECK-NEXT: NoAlias: created protector node #3 for 'a' in activation #3 based on raw/root
+; CHECK-NEXT: store ptr %p, ptr %slot, align 8
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #3
+; CHECK-NEXT: Exiting function: capture
+; CHECK-NEXT: call void @capture(ptr %a, ptr %slot)
+; CHECK-NEXT: %stale = load ptr, ptr %slot, align 8 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: write_one
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #4 for 'a' in activation #4 based on raw/root
+; CHECK-NEXT: NoAlias: activation #4 write through node #4 on 'a' bytes [0, 4): unaccessed -> access including a write by node #4
+; CHECK-NEXT: NoAlias: write through node #4 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 3, ptr %p, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #4
+; CHECK-NEXT: Exiting function: write_one
+; CHECK-NEXT: call void @write_one(ptr %stale)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_free.ll b/llvm/test/tools/llubi/noalias_free.ll
new file mode 100644
index 00000000000000..06b1084de54020
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_free.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Deallocation must check active protectors before dropping allocation state.
+
+declare ptr @malloc(i64)
+declare void @free(ptr)
+
+define void @free_bad(ptr noalias %p, ptr %raw) {
+ store i32 1, ptr %p
+ call void @free(ptr %raw)
+ ret void
+}
+
+define void @main() {
+ %a = call ptr @malloc(i64 4)
+ call void @free_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = call ptr @malloc(i64 4) => ptr 0x10 [a]
+; CHECK-NEXT: Entering function: free_bad
+; CHECK-NEXT: ptr %p = ptr 0x10 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x10 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: deallocation through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @free(ptr %raw) at @free_bad <stdin>:11
+; CHECK-NEXT: #1 call void @free_bad(ptr %a, ptr %a) at @main <stdin>:17
+; CHECK-NEXT: Immediate UB detected: noalias violation: deallocation through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_histogram.ll b/llvm/test/tools/llubi/noalias_histogram.ll
new file mode 100644
index 00000000000000..d426b13bc8f1a6
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_histogram.ll
@@ -0,0 +1,33 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Active histogram lanes are writes for noalias checking.
+
+define void @outer(ptr noalias %p, ptr %raw) {
+ store i32 0, ptr %p
+ %v = insertelement <2 x ptr> poison, ptr %raw, i32 0
+ call void @llvm.experimental.vector.histogram.add.v2p0.i32(<2 x ptr> %v, i32 1, <2 x i1> <i1 true, i1 false>)
+ ret void
+}
+define void @main() {
+ %a = alloca i32
+ call void @outer(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: outer
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 0, ptr %p, align 4
+; CHECK-NEXT: %v = insertelement <2 x ptr> poison, ptr %raw, i32 0 => { ptr 0x8 [a], poison }
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.experimental.vector.histogram.add.v2p0.i32(<2 x ptr> %v, i32 1, <2 x i1> <i1 true, i1 false>) at @outer <stdin>:9
+; CHECK-NEXT: #1 call void @outer(ptr %a, ptr %a) at @main <stdin>:14
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_libc_read.ll b/llvm/test/tools/llubi/noalias_libc_read.ll
new file mode 100644
index 00000000000000..e84fb4aa159540
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_libc_read.ll
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Even reading the terminating null byte is a foreign read.
+
+declare i32 @puts(ptr)
+define void @outer(ptr noalias %p, ptr %raw) {
+ store i8 0, ptr %p
+ %r = call i32 @puts(ptr %raw)
+ ret void
+}
+define void @main() {
+ %a = alloca i8
+ call void @outer(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i8, align 1 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: outer
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 1): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 1) checked 1 active noalias activation
+; CHECK-NEXT: store i8 0, ptr %p, align 1
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 1) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %r = call i32 @puts(ptr %raw) at @outer <stdin>:9
+; CHECK-NEXT: #1 call void @outer(ptr %a, ptr %a) at @main <stdin>:14
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 1) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_memcpy.ll b/llvm/test/tools/llubi/noalias_memcpy.ll
new file mode 100644
index 00000000000000..1343b2051bb68d
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_memcpy.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A foreign memcpy source is a read; the destination is a distinct allocation.
+
+declare void @llvm.memcpy.p0.p0.i64(ptr, ptr, i64, i1)
+
+define void @memcpy_bad(ptr noalias %p, ptr %raw) {
+ %dst = alloca i32
+ store i32 1, ptr %p
+ call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %raw, i64 4, i1 false)
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @memcpy_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: memcpy_bad
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: %dst = alloca i32, align 4 => ptr 0x10 [dst]
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: created protector node #2 for 'dst' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #3 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %raw, i64 4, i1 false) at @memcpy_bad <stdin>:11
+; CHECK-NEXT: #1 call void @memcpy_bad(ptr %a, ptr %a) at @main <stdin>:17
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_memcpy_destination.ll b/llvm/test/tools/llubi/noalias_memcpy_destination.ll
new file mode 100644
index 00000000000000..b33af58168adc4
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_memcpy_destination.ll
@@ -0,0 +1,43 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A foreign memcpy destination must be recorded as a write.
+
+declare void @llvm.memcpy.p0.p0.i64(ptr, ptr, i64, i1)
+
+define void @memcpy_bad(ptr noalias %p, ptr %raw) {
+ %src = alloca i32
+ store i32 0, ptr %src
+ store i32 1, ptr %p
+ call void @llvm.memcpy.p0.p0.i64(ptr %raw, ptr %src, i64 4, i1 false)
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @memcpy_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: memcpy_bad
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: %src = alloca i32, align 4 => ptr 0x10 [src]
+; CHECK-NEXT: store i32 0, ptr %src, align 4
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #3 for 'src' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: activation #2 read through node #3 on 'src' bytes [0, 4): unaccessed -> reads by node #3
+; CHECK-NEXT: NoAlias: read through node #3 on 'src' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.memcpy.p0.p0.i64(ptr %raw, ptr %src, i64 4, i1 false) at @memcpy_bad <stdin>:12
+; CHECK-NEXT: #1 call void @memcpy_bad(ptr %a, ptr %a) at @main <stdin>:18
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_memmove.ll b/llvm/test/tools/llubi/noalias_memmove.ll
new file mode 100644
index 00000000000000..5de62e21925253
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_memmove.ll
@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A foreign memmove source is a read; the destination is a distinct allocation.
+
+declare void @llvm.memmove.p0.p0.i64(ptr, ptr, i64, i1)
+
+define void @memmove_bad(ptr noalias %p, ptr %raw) {
+ %dst = alloca i32
+ store i32 1, ptr %p
+ call void @llvm.memmove.p0.p0.i64(ptr %dst, ptr %raw, i64 4, i1 false)
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @memmove_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: memmove_bad
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: %dst = alloca i32, align 4 => ptr 0x10 [dst]
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.memmove.p0.p0.i64(ptr %dst, ptr %raw, i64 4, i1 false) at @memmove_bad <stdin>:11
+; CHECK-NEXT: #1 call void @memmove_bad(ptr %a, ptr %a) at @main <stdin>:17
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_memory_effects_valid.ll b/llvm/test/tools/llubi/noalias_memory_effects_valid.ll
new file mode 100644
index 00000000000000..9d40806eda9616
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_memory_effects_valid.ll
@@ -0,0 +1,131 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Zero-length and masked-off accesses do not conflict; local effects remain valid.
+
+declare void @llvm.memset.p0.i64(ptr, i8, i64, i1)
+declare void @llvm.memcpy.p0.p0.i64(ptr, ptr, i64, i1)
+declare void @llvm.memmove.p0.p0.i64(ptr, ptr, i64, i1)
+declare ptr @malloc(i64)
+declare void @free(ptr)
+declare i32 @puts(ptr)
+
+define void @outer(ptr noalias %p, ptr %raw) {
+ store i32 0, ptr %p
+ call void @llvm.memset.p0.i64(ptr %raw, i8 1, i64 0, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr %raw, ptr %raw, i64 0, i1 false)
+ %v = insertelement <2 x ptr> poison, ptr %raw, i32 0
+ %ptrs = insertelement <2 x ptr> %v, ptr %p, i32 1
+ call void @llvm.experimental.vector.histogram.add.v2p0.i32(<2 x ptr> %ptrs, i32 1, <2 x i1> <i1 false, i1 true>)
+ %dst = alloca i32
+ call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %p, i64 4, i1 false)
+ call void @llvm.memmove.p0.p0.i64(ptr %p, ptr %p, i64 4, i1 false)
+ call void @llvm.memset.p0.i64(ptr %p, i8 65, i64 1, i1 false)
+ %r = call i32 @puts(ptr %p)
+ call void @free(ptr %p)
+ ret void
+}
+define void @unused(ptr noalias %p) {
+ ret void
+}
+define void @foreign_free(ptr noalias %unused, ptr %raw) {
+ call void @free(ptr %raw)
+ ret void
+}
+define void @main() {
+ %a = call ptr @malloc(i64 4)
+ call void @outer(ptr %a, ptr %a)
+ %b = call ptr @malloc(i64 4)
+ call void @foreign_free(ptr %b, ptr %b)
+ call void @unused(ptr null)
+ call void @unused(ptr poison)
+ %bits = ptrtoint ptr @unused to i64
+ %wild = inttoptr i64 4096 to ptr
+ call void @unused(ptr %wild)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = call ptr @malloc(i64 4) => ptr 0x10 [a]
+; CHECK-NEXT: Entering function: outer
+; CHECK-NEXT: ptr %p = ptr 0x10 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x10 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 0, ptr %p, align 4
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr %raw, i8 1, i64 0, i1 false)
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #3 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr %raw, ptr %raw, i64 0, i1 false)
+; CHECK-NEXT: %v = insertelement <2 x ptr> poison, ptr %raw, i32 0 => { ptr 0x10 [a], poison }
+; CHECK-NEXT: %ptrs = insertelement <2 x ptr> %v, ptr %p, i32 1 => { ptr 0x10 [a], ptr 0x10 [a] }
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: call void @llvm.experimental.vector.histogram.add.v2p0.i32(<2 x ptr> %ptrs, i32 1, <2 x i1> <i1 false, i1 true>)
+; CHECK-NEXT: %dst = alloca i32, align 4 => ptr 0x18 [dst]
+; CHECK-NEXT: NoAlias: created protector node #4 for 'dst' in activation #3 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #5 for 'a' in activation #3 based on node #1
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: activation #3 read through node #5 on 'a' bytes [0, 4): unaccessed -> reads by node #5
+; CHECK-NEXT: NoAlias: read through node #5 on 'a' bytes [0, 4) checked 2 active noalias activations
+; CHECK-NEXT: NoAlias: activation #3 write through node #4 on 'dst' bytes [0, 4): unaccessed -> access including a write by node #4
+; CHECK-NEXT: NoAlias: write through node #4 on 'dst' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: NoAlias: ended activation #3
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr %dst, ptr %p, i64 4, i1 false)
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: call void @llvm.memmove.p0.p0.i64(ptr %p, ptr %p, i64 4, i1 false)
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 1): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 1) checked 1 active noalias activation
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr %p, i8 65, i64 1, i1 false)
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 1): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 1) checked 1 active noalias activation
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [1, 2): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [1, 2) checked 1 active noalias activation
+; CHECK-NEXT: A
+; CHECK-NEXT: %r = call i32 @puts(ptr %p) => i32 1
+; CHECK-NEXT: NoAlias: activation #1 deallocation through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: deallocation through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: call void @free(ptr %p)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: outer
+; CHECK-NEXT: call void @outer(ptr %a, ptr %a)
+; CHECK-NEXT: %b = call ptr @malloc(i64 4) => ptr 0x20 [b]
+; CHECK-NEXT: Entering function: foreign_free
+; CHECK-NEXT: ptr %unused = ptr 0x20 [b]
+; CHECK-NEXT: ptr %raw = ptr 0x20 [b]
+; CHECK-NEXT: NoAlias: created protector node #6 for 'b' in activation #4 based on raw/root
+; CHECK-NEXT: NoAlias: activation #4 deallocation through raw/root on 'b' bytes [0, 4): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: deallocation through raw/root on 'b' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: call void @free(ptr %raw)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #4
+; CHECK-NEXT: Exiting function: foreign_free
+; CHECK-NEXT: call void @foreign_free(ptr %b, ptr %b)
+; CHECK-NEXT: Entering function: unused
+; CHECK-NEXT: ptr %p = ptr 0x0 [nullary]
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #5
+; CHECK-NEXT: Exiting function: unused
+; CHECK-NEXT: call void @unused(ptr null)
+; CHECK-NEXT: Entering function: unused
+; CHECK-NEXT: ptr %p = poison
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: unused
+; CHECK-NEXT: call void @unused(ptr poison)
+; CHECK-NEXT: %bits = ptrtoint ptr @unused to i64 => i64 8
+; CHECK-NEXT: %wild = inttoptr i64 4096 to ptr => ptr 0x1000 [wildcard]
+; CHECK-NEXT: Entering function: unused
+; CHECK-NEXT: ptr %p = ptr 0x1000 [wildcard]
+; CHECK-NEXT: NoAlias: created protector node #7 for wildcard provenance in activation #6 based on raw/root
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #6
+; CHECK-NEXT: Exiting function: unused
+; CHECK-NEXT: call void @unused(ptr %wild)
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_memset.ll b/llvm/test/tools/llubi/noalias_memset.ll
new file mode 100644
index 00000000000000..0a855204bf94e8
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_memset.ll
@@ -0,0 +1,34 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A foreign memset is a write, even though it does not use ExecutorBase::store.
+
+declare void @llvm.memset.p0.i64(ptr, i8, i64, i1)
+
+define void @memset_bad(ptr noalias %p, ptr %raw) {
+ store i32 1, ptr %p
+ call void @llvm.memset.p0.i64(ptr %raw, i8 0, i64 4, i1 false)
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @memset_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: memset_bad
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.memset.p0.i64(ptr %raw, i8 0, i64 4, i1 false) at @memset_bad <stdin>:10
+; CHECK-NEXT: #1 call void @memset_bad(ptr %a, ptr %a) at @main <stdin>:16
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_memset_inline.ll b/llvm/test/tools/llubi/noalias_memset_inline.ll
new file mode 100644
index 00000000000000..47cf03e81ef4e3
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_memset_inline.ll
@@ -0,0 +1,34 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A foreign memset is a write, even though it does not use ExecutorBase::store.
+
+declare void @llvm.memset.inline.p0.i64(ptr, i8, i64, i1)
+
+define void @memset_bad(ptr noalias %p, ptr %raw) {
+ store i32 1, ptr %p
+ call void @llvm.memset.inline.p0.i64(ptr %raw, i8 0, i64 4, i1 false)
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @memset_bad(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: memset_bad
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 call void @llvm.memset.inline.p0.i64(ptr %raw, i8 0, i64 4, i1 false) at @memset_bad <stdin>:10
+; CHECK-NEXT: #1 call void @memset_bad(ptr %a, ptr %a) at @main <stdin>:16
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_nested_activations.ll b/llvm/test/tools/llubi/noalias_nested_activations.ll
index 1cd8cff29b6737..985ba9ea8bf34b 100644
--- a/llvm/test/tools/llubi/noalias_nested_activations.ll
+++ b/llvm/test/tools/llubi/noalias_nested_activations.ll
@@ -42,7 +42,6 @@ define void @main() {
; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 2 active noalias activations
; CHECK-NEXT: store i32 1, ptr %x, align 4
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #2
; CHECK-NEXT: NoAlias: ended activation #2
; CHECK-NEXT: Exiting function: write_inner
; CHECK-NEXT: call void @write_inner(ptr %x)
@@ -50,7 +49,6 @@ define void @main() {
; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
; CHECK-NEXT: %v = load i32, ptr %x, align 4 => i32 1
; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
; CHECK-NEXT: NoAlias: ended activation #1
; CHECK-NEXT: Exiting function: outer_ok
; CHECK-NEXT: call void @outer_ok(ptr %a)
diff --git a/llvm/test/tools/llubi/noalias_outside_range.ll b/llvm/test/tools/llubi/noalias_outside_range.ll
index 0db9d92ad235da..a1c36c10c0595c 100644
--- a/llvm/test/tools/llubi/noalias_outside_range.ll
+++ b/llvm/test/tools/llubi/noalias_outside_range.ll
@@ -19,6 +19,7 @@ define void @stuff(ptr noalias %x, ptr %raw) {
define void @main() {
%data = alloca [4 x i8]
+ store [4 x i8] [i8 0, i8 1, i8 2, i8 3], ptr %data
%raw = getelementptr [4 x i8], ptr %data, i64 0, i64 0
call void @stuff(ptr %raw, ptr %raw)
ret void
@@ -26,6 +27,7 @@ define void @main() {
; CHECK: Entering function: main
; CHECK-NEXT: %data = alloca [4 x i8], align 1 => ptr 0x8 [data]
+; CHECK-NEXT: store [4 x i8] c"\00\01\02\03", ptr %data, align 1
; CHECK-NEXT: %raw = getelementptr [4 x i8], ptr %data, i64 0, i64 0 => ptr 0x8 [data]
; CHECK-NEXT: Entering function: stuff
; CHECK-NEXT: ptr %x = ptr 0x8 [data]
@@ -38,15 +40,15 @@ define void @main() {
; CHECK-NEXT: %x2 = getelementptr i8, ptr %x, i64 2 => ptr 0xA [data + 2]
; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'data' bytes [2, 3): unaccessed -> reads by node #1
; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [2, 3) checked 1 active noalias activation
-; CHECK-NEXT: %v2 = load i8, ptr %x2, align 1 => i8 62
+; CHECK-NEXT: %v2 = load i8, ptr %x2, align 1 => i8 2
; CHECK-NEXT: %x3 = getelementptr i8, ptr %x, i64 3 => ptr 0xB [data + 3]
; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'data' bytes [3, 4): unaccessed -> reads by node #1
; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [3, 4) checked 1 active noalias activation
-; CHECK-NEXT: %v3 = load i8, ptr %x3, align 1 => i8 -117
+; CHECK-NEXT: %v3 = load i8, ptr %x3, align 1 => i8 3
; CHECK-NEXT: %raw3 = getelementptr i8, ptr %raw, i64 3 => ptr 0xB [data + 3]
; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'data' bytes [3, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: Stacktrace:
; CHECK-NEXT: #0 store i8 42, ptr %raw3, align 1 at @stuff <stdin>:16
-; CHECK-NEXT: #1 call void @stuff(ptr %raw, ptr %raw) at @main <stdin>:23
+; CHECK-NEXT: #1 call void @stuff(ptr %raw, ptr %raw) at @main <stdin>:24
; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'data' bytes [3, 4) combines multiple access classes with a write in activation #1
; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_outside_range_foreign_first.ll b/llvm/test/tools/llubi/noalias_outside_range_foreign_first.ll
new file mode 100644
index 00000000000000..477fbf9784507f
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_outside_range_foreign_first.ll
@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Variant of Miri's tests/fail/tree_borrows/outside-range.rs with the access
+; order reversed. The foreign write to byte 1 is initially allowed, but the
+; subsequent local read of that byte must fail. Access history must include
+; foreign writes even before the first local access to the affected bytes.
+
+define void @foreign_first(ptr noalias %x, ptr %raw) {
+ %raw1 = getelementptr i8, ptr %raw, i64 1
+ store i8 42, ptr %raw1
+ %x1 = getelementptr i8, ptr %x, i64 1
+ %v = load i8, ptr %x1
+ ret void
+}
+
+define void @main() {
+ %data = alloca [4 x i8]
+ store [4 x i8] [i8 0, i8 1, i8 2, i8 3], ptr %data
+ call void @foreign_first(ptr %data, ptr %data)
+ ret void
+}
+; CHECK: Entering function: main
+; CHECK-NEXT: %data = alloca [4 x i8], align 1 => ptr 0x8 [data]
+; CHECK-NEXT: store [4 x i8] c"\00\01\02\03", ptr %data, align 1
+; CHECK-NEXT: Entering function: foreign_first
+; CHECK-NEXT: ptr %x = ptr 0x8 [data]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [data]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'data' in activation #1 based on raw/root
+; CHECK-NEXT: %raw1 = getelementptr i8, ptr %raw, i64 1 => ptr 0x9 [data + 1]
+; CHECK-NEXT: NoAlias: activation #1 write through raw/root on 'data' bytes [1, 2): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [1, 2) checked 1 active noalias activation
+; CHECK-NEXT: store i8 42, ptr %raw1, align 1
+; CHECK-NEXT: %x1 = getelementptr i8, ptr %x, i64 1 => ptr 0x9 [data + 1]
+; CHECK-NEXT: NoAlias: noalias violation: read through node #1 on 'data' bytes [1, 2) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i8, ptr %x1, align 1 at @foreign_first <stdin>:13
+; CHECK-NEXT: #1 call void @foreign_first(ptr %data, ptr %data) at @main <stdin>:20
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through node #1 on 'data' bytes [1, 2) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_outside_range_unused.ll b/llvm/test/tools/llubi/noalias_outside_range_unused.ll
new file mode 100644
index 00000000000000..76a19806a72a1c
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_outside_range_unused.ll
@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Passing variant of Miri's tests/fail/tree_borrows/outside-range.rs.
+; Foreign writes to bytes never accessed through x are allowed, both before
+; and after local accesses to other bytes. This remains valid on return.
+
+define void @disjoint(ptr noalias %x, ptr %raw) {
+ %raw1 = getelementptr i8, ptr %raw, i64 1
+ store i8 42, ptr %raw1
+ %x2 = getelementptr i8, ptr %x, i64 2
+ %v2 = load i8, ptr %x2
+ %raw3 = getelementptr i8, ptr %raw, i64 3
+ store i8 42, ptr %raw3
+ ret void
+}
+
+define void @main() {
+ %data = alloca [4 x i8]
+ store [4 x i8] [i8 0, i8 1, i8 2, i8 3], ptr %data
+ call void @disjoint(ptr %data, ptr %data)
+ %v = load [4 x i8], ptr %data
+ ret void
+}
+; CHECK: Entering function: main
+; CHECK-NEXT: %data = alloca [4 x i8], align 1 => ptr 0x8 [data]
+; CHECK-NEXT: store [4 x i8] c"\00\01\02\03", ptr %data, align 1
+; CHECK-NEXT: Entering function: disjoint
+; CHECK-NEXT: ptr %x = ptr 0x8 [data]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [data]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'data' in activation #1 based on raw/root
+; CHECK-NEXT: %raw1 = getelementptr i8, ptr %raw, i64 1 => ptr 0x9 [data + 1]
+; CHECK-NEXT: NoAlias: activation #1 write through raw/root on 'data' bytes [1, 2): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [1, 2) checked 1 active noalias activation
+; CHECK-NEXT: store i8 42, ptr %raw1, align 1
+; CHECK-NEXT: %x2 = getelementptr i8, ptr %x, i64 2 => ptr 0xA [data + 2]
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'data' bytes [2, 3): unaccessed -> reads by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'data' bytes [2, 3) checked 1 active noalias activation
+; CHECK-NEXT: %v2 = load i8, ptr %x2, align 1 => i8 2
+; CHECK-NEXT: %raw3 = getelementptr i8, ptr %raw, i64 3 => ptr 0xB [data + 3]
+; CHECK-NEXT: NoAlias: activation #1 write through raw/root on 'data' bytes [3, 4): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: write through raw/root on 'data' bytes [3, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i8 42, ptr %raw3, align 1
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: disjoint
+; CHECK-NEXT: call void @disjoint(ptr %data, ptr %data)
+; CHECK-NEXT: %v = load [4 x i8], ptr %data, align 1 => { i8 0, i8 42, i8 2, i8 42 }
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_prune_stale_node.ll b/llvm/test/tools/llubi/noalias_prune_stale_node.ll
deleted file mode 100644
index 1d91bd9022b90c..00000000000000
--- a/llvm/test/tools/llubi/noalias_prune_stale_node.ll
+++ /dev/null
@@ -1,49 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
-; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
-
-define void @capture(ptr noalias %x, ptr %slot) {
- store ptr %x, ptr %slot
- ret void
-}
-
-define void @write_one(ptr noalias %x) {
- store i32 1, ptr %x
- ret void
-}
-
-define void @main() {
- %a = alloca i32
- %slot = alloca ptr
- call void @capture(ptr %a, ptr %slot)
- %stale = load ptr, ptr %slot
- call void @write_one(ptr %stale)
- ret void
-}
-
-; CHECK: Entering function: main
-; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
-; CHECK-NEXT: %slot = alloca ptr, align 8 => ptr 0x10 [slot]
-; CHECK-NEXT: Entering function: capture
-; CHECK-NEXT: ptr %x = ptr 0x8 [a]
-; CHECK-NEXT: ptr %slot = ptr 0x10 [slot]
-; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
-; CHECK-NEXT: store ptr %x, ptr %slot, align 8
-; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #1
-; CHECK-NEXT: NoAlias: ended activation #1
-; CHECK-NEXT: Exiting function: capture
-; CHECK-NEXT: call void @capture(ptr %a, ptr %slot)
-; CHECK-NEXT: %stale = load ptr, ptr %slot, align 8 => ptr 0x8 [a]
-; CHECK-NEXT: Entering function: write_one
-; CHECK-NEXT: ptr %x = ptr 0x8 [a]
-; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on raw/root
-; CHECK-NEXT: NoAlias: activation #2 write through node #2 on 'a' bytes [0, 4): unaccessed -> access including a write by node #2
-; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
-; CHECK-NEXT: store i32 1, ptr %x, align 4
-; CHECK-NEXT: ret void
-; CHECK-NEXT: NoAlias: erased inactive protector node #2
-; CHECK-NEXT: NoAlias: ended activation #2
-; CHECK-NEXT: Exiting function: write_one
-; CHECK-NEXT: call void @write_one(ptr %stale)
-; CHECK-NEXT: ret void
-; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_returned_pointer.ll b/llvm/test/tools/llubi/noalias_returned_pointer.ll
new file mode 100644
index 00000000000000..ebf39ac30e27a5
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_returned_pointer.ll
@@ -0,0 +1,64 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; A returned noalias pointer remains based on the still-active outer argument.
+
+define ptr @identity(ptr noalias %p) {
+ ret ptr %p
+}
+
+define void @returned_outer(ptr noalias %p) {
+ store i32 1, ptr %p
+ %q = call ptr @identity(ptr %p)
+ store i32 2, ptr %q
+ ; Retagging a returned pointer must also retain the inactive intermediate node.
+ %r = call ptr @identity(ptr %q)
+ store i32 3, ptr %r
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @returned_outer(ptr %a)
+ ; The root pointer is usable again after all protectors have ended.
+ %v = load i32, ptr %a
+ store i32 4, ptr %a
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: returned_outer
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: Entering function: identity
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on node #1
+; CHECK-NEXT: ret ptr %p
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: Exiting function: identity
+; CHECK-NEXT: %q = call ptr @identity(ptr %p) => ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 2, ptr %q, align 4
+; CHECK-NEXT: Entering function: identity
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #3 for 'a' in activation #3 based on node #2
+; CHECK-NEXT: ret ptr %p
+; CHECK-NEXT: NoAlias: ended activation #3
+; CHECK-NEXT: Exiting function: identity
+; CHECK-NEXT: %r = call ptr @identity(ptr %q) => ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): access including a write by node #1 -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #3 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 3, ptr %r, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: returned_outer
+; CHECK-NEXT: call void @returned_outer(ptr %a)
+; CHECK-NEXT: %v = load i32, ptr %a, align 4 => i32 3
+; CHECK-NEXT: store i32 4, ptr %a, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/noalias_returned_pointer_foreign_access.ll b/llvm/test/tools/llubi/noalias_returned_pointer_foreign_access.ll
new file mode 100644
index 00000000000000..12686bf4eb4341
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_returned_pointer_foreign_access.ll
@@ -0,0 +1,44 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; After an inner return, its pointer still conflicts with an outer foreign alias.
+
+define ptr @identity(ptr noalias %p) {
+ ret ptr %p
+}
+
+define void @escaped_bad_outer(ptr noalias %p, ptr %raw) {
+ %q = call ptr @identity(ptr %p)
+ store i32 1, ptr %q
+ store i32 2, ptr %raw
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ call void @escaped_bad_outer(ptr %a, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: Entering function: escaped_bad_outer
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: ptr %raw = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: Entering function: identity
+; CHECK-NEXT: ptr %p = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #2 based on node #1
+; CHECK-NEXT: ret ptr %p
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: Exiting function: identity
+; CHECK-NEXT: %q = call ptr @identity(ptr %p) => ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %q, align 4
+; CHECK-NEXT: NoAlias: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 store i32 2, ptr %raw, align 4 at @escaped_bad_outer <stdin>:13
+; CHECK-NEXT: #1 call void @escaped_bad_outer(ptr %a, ptr %a) at @main <stdin>:19
+; CHECK-NEXT: Immediate UB detected: noalias violation: write through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_wildcard.ll b/llvm/test/tools/llubi/noalias_wildcard.ll
new file mode 100644
index 00000000000000..6a4e83676e4340
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_wildcard.ll
@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; An inttoptr argument must get a noalias node even before its object is resolved.
+
+define void @write_read(ptr noalias %p, ptr %q) {
+ store i32 1, ptr %p
+ %v = load i32, ptr %q
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ %n = ptrtoint ptr %a to i64
+ %p = inttoptr i64 %n to ptr
+ call void @write_read(ptr %p, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: %n = ptrtoint ptr %a to i64 => i64 8
+; CHECK-NEXT: %p = inttoptr i64 %n to ptr => ptr 0x8 [wildcard]
+; CHECK-NEXT: Entering function: write_read
+; CHECK-NEXT: ptr %p = ptr 0x8 [wildcard]
+; CHECK-NEXT: ptr %q = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for wildcard provenance in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through node #1 on 'a' bytes [0, 4): unaccessed -> access including a write by node #1
+; CHECK-NEXT: NoAlias: write through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i32, ptr %q, align 4 at @write_read <stdin>:8
+; CHECK-NEXT: #1 call void @write_read(ptr %p, ptr %a) at @main <stdin>:16
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through raw/root on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_wildcard_foreign_first.ll b/llvm/test/tools/llubi/noalias_wildcard_foreign_first.ll
new file mode 100644
index 00000000000000..0223186292a8eb
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_wildcard_foreign_first.ll
@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Foreign accesses must be recorded before the first wildcard access.
+
+define void @write_read(ptr noalias %p, ptr %q) {
+ store i32 1, ptr %q
+ %v = load i32, ptr %p
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ %n = ptrtoint ptr %a to i64
+ %p = inttoptr i64 %n to ptr
+ call void @write_read(ptr %p, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: %n = ptrtoint ptr %a to i64 => i64 8
+; CHECK-NEXT: %p = inttoptr i64 %n to ptr => ptr 0x8 [wildcard]
+; CHECK-NEXT: Entering function: write_read
+; CHECK-NEXT: ptr %p = ptr 0x8 [wildcard]
+; CHECK-NEXT: ptr %q = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for wildcard provenance in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through raw/root on 'a' bytes [0, 4): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: write through raw/root on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %q, align 4
+; CHECK-NEXT: NoAlias: noalias violation: read through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i32, ptr %p, align 4 at @write_read <stdin>:8
+; CHECK-NEXT: #1 call void @write_read(ptr %p, ptr %a) at @main <stdin>:16
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_wildcard_outside_allocation.ll b/llvm/test/tools/llubi/noalias_wildcard_outside_allocation.ll
new file mode 100644
index 00000000000000..6f97af0b5df8f8
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_wildcard_outside_allocation.ll
@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: not llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Retagging an out-of-bounds wildcard must not require dereferenceability.
+
+define void @write_read(ptr noalias %p, ptr %q) {
+ store i32 1, ptr %q
+ %inside = getelementptr i8, ptr %p, i64 -4096
+ %v = load i32, ptr %inside
+ ret void
+}
+
+define void @main() {
+ %a = alloca i32
+ %n = ptrtoint ptr %a to i64
+ %p = inttoptr i64 %n to ptr
+ %outside = getelementptr i8, ptr %p, i64 4096
+ call void @write_read(ptr %outside, ptr %a)
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca i32, align 4 => ptr 0x8 [a]
+; CHECK-NEXT: %n = ptrtoint ptr %a to i64 => i64 8
+; CHECK-NEXT: %p = inttoptr i64 %n to ptr => ptr 0x8 [wildcard]
+; CHECK-NEXT: %outside = getelementptr i8, ptr %p, i64 4096 => ptr 0x1008 [wildcard]
+; CHECK-NEXT: Entering function: write_read
+; CHECK-NEXT: ptr %p = ptr 0x1008 [wildcard]
+; CHECK-NEXT: ptr %q = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for wildcard provenance in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 write through raw/root on 'a' bytes [0, 4): unaccessed -> access including a write by raw/root
+; CHECK-NEXT: NoAlias: write through raw/root on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %q, align 4
+; CHECK-NEXT: %inside = getelementptr i8, ptr %p, i64 -4096 => ptr 0x8 [wildcard]
+; CHECK-NEXT: NoAlias: noalias violation: read through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: Stacktrace:
+; CHECK-NEXT: #0 %v = load i32, ptr %inside, align 4 at @write_read <stdin>:9
+; CHECK-NEXT: #1 call void @write_read(ptr %outside, ptr %a) at @main <stdin>:18
+; CHECK-NEXT: Immediate UB detected: noalias violation: read through node #1 on 'a' bytes [0, 4) combines multiple access classes with a write in activation #1
+; CHECK-NEXT: error: Execution of function 'main' failed.
diff --git a/llvm/test/tools/llubi/noalias_wildcard_valid.ll b/llvm/test/tools/llubi/noalias_wildcard_valid.ll
new file mode 100644
index 00000000000000..b076fa98382596
--- /dev/null
+++ b/llvm/test/tools/llubi/noalias_wildcard_valid.ll
@@ -0,0 +1,69 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
+; RUN: llubi --experimental-noalias --verbose < %s 2>&1 | FileCheck %s
+
+; Wildcard nodes do not make unrelated or read-only accesses conflict. A frame
+; can contain both wildcard and concrete noalias arguments to the same object.
+
+define void @read_both(ptr noalias %p, ptr noalias %q) {
+ %x = load i32, ptr %p
+ %y = load i32, ptr %q
+ ret void
+}
+
+define void @write_disjoint(ptr noalias %p, ptr noalias %q) {
+ store i32 1, ptr %p
+ store i32 2, ptr %q
+ ret void
+}
+
+define void @main() {
+ %a = alloca [2 x i32]
+ store [2 x i32] zeroinitializer, ptr %a
+ %b = getelementptr i32, ptr %a, i64 1
+ %n = ptrtoint ptr %a to i64
+ %p = inttoptr i64 %n to ptr
+ call void @read_both(ptr %p, ptr %a)
+ call void @write_disjoint(ptr %p, ptr %b)
+ %result = load [2 x i32], ptr %a
+ ret void
+}
+
+; CHECK: Entering function: main
+; CHECK-NEXT: %a = alloca [2 x i32], align 4 => ptr 0x8 [a]
+; CHECK-NEXT: store [2 x i32] zeroinitializer, ptr %a, align 4
+; CHECK-NEXT: %b = getelementptr i32, ptr %a, i64 1 => ptr 0xC [a + 4]
+; CHECK-NEXT: %n = ptrtoint ptr %a to i64 => i64 8
+; CHECK-NEXT: %p = inttoptr i64 %n to ptr => ptr 0x8 [wildcard]
+; CHECK-NEXT: Entering function: read_both
+; CHECK-NEXT: ptr %p = ptr 0x8 [wildcard]
+; CHECK-NEXT: ptr %q = ptr 0x8 [a]
+; CHECK-NEXT: NoAlias: created protector node #1 for wildcard provenance in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #2 for 'a' in activation #1 based on raw/root
+; CHECK-NEXT: NoAlias: activation #1 read through node #1 on 'a' bytes [0, 4): unaccessed -> reads by node #1
+; CHECK-NEXT: NoAlias: read through node #1 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: %x = load i32, ptr %p, align 4 => i32 0
+; CHECK-NEXT: NoAlias: activation #1 read through node #2 on 'a' bytes [0, 4): reads by node #1 -> reads by multiple access classes
+; CHECK-NEXT: NoAlias: read through node #2 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: %y = load i32, ptr %q, align 4 => i32 0
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #1
+; CHECK-NEXT: Exiting function: read_both
+; CHECK-NEXT: call void @read_both(ptr %p, ptr %a)
+; CHECK-NEXT: Entering function: write_disjoint
+; CHECK-NEXT: ptr %p = ptr 0x8 [wildcard]
+; CHECK-NEXT: ptr %q = ptr 0xC [a + 4]
+; CHECK-NEXT: NoAlias: created protector node #3 for wildcard provenance in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: created protector node #4 for 'a' in activation #2 based on raw/root
+; CHECK-NEXT: NoAlias: activation #2 write through node #3 on 'a' bytes [0, 4): unaccessed -> access including a write by node #3
+; CHECK-NEXT: NoAlias: write through node #3 on 'a' bytes [0, 4) checked 1 active noalias activation
+; CHECK-NEXT: store i32 1, ptr %p, align 4
+; CHECK-NEXT: NoAlias: activation #2 write through node #4 on 'a' bytes [4, 8): unaccessed -> access including a write by node #4
+; CHECK-NEXT: NoAlias: write through node #4 on 'a' bytes [4, 8) checked 1 active noalias activation
+; CHECK-NEXT: store i32 2, ptr %q, align 4
+; CHECK-NEXT: ret void
+; CHECK-NEXT: NoAlias: ended activation #2
+; CHECK-NEXT: Exiting function: write_disjoint
+; CHECK-NEXT: call void @write_disjoint(ptr %p, ptr %b)
+; CHECK-NEXT: %result = load [2 x i32], ptr %a, align 4 => { i32 1, i32 2 }
+; CHECK-NEXT: ret void
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/tools/llubi/lib/Context.cpp b/llvm/tools/llubi/lib/Context.cpp
index 6aec7e413068f3..14d09d91f8c701 100644
--- a/llvm/tools/llubi/lib/Context.cpp
+++ b/llvm/tools/llubi/lib/Context.cpp
@@ -1379,9 +1379,8 @@ bool MemoryObject::isHeapAllocated() const {
bool Context::isNoAliasAncestor(uint64_t Ancestor, uint64_t Descendant) const {
if (!Ancestor || !Descendant)
return false;
- // Parent links are stable while a descendant is active. If a stale node id
- // was pruned, reaching a missing node means the relationship no longer
- // exists.
+ // Inactive nodes retain parent links: returned and escaped pointers can
+ // still be based on an active ancestor.
for (uint64_t NodeID = Descendant; NodeID;) {
if (NodeID == Ancestor)
return true;
@@ -1393,39 +1392,14 @@ bool Context::isNoAliasAncestor(uint64_t Ancestor, uint64_t Descendant) const {
return false;
}
-bool Context::hasActiveNoAliasDescendant(uint64_t NodeID) const {
- for (const auto &[CandidateID, Candidate] : NoAliasNodes) {
- if (!Candidate.Active || CandidateID == NodeID)
- continue;
- if (isNoAliasAncestor(NodeID, CandidateID))
- return true;
- }
- return false;
-}
-
-void Context::tryEraseInactiveNoAliasNode(uint64_t NodeID) {
- const auto It = NoAliasNodes.find(NodeID);
- if (It == NoAliasNodes.end() || It->second.Active)
- return;
- if (hasActiveNoAliasDescendant(NodeID))
- return;
-
- // An inactive node can still be relevant as the parent of a live child. Once
- // that is no longer true, stale pointers carrying this ID should behave like
- // raw/root pointers during future retagging.
- const uint64_t Parent = It->second.Parent;
- appendNoAliasEvent("erased inactive protector " + getNoAliasNodeName(NodeID));
- NoAliasNodes.erase(It);
- if (Parent)
- tryEraseInactiveNoAliasNode(Parent);
-}
-
StringRef Context::getNoAliasAccessKindName(NoAliasAccessKind Kind) {
switch (Kind) {
case NoAliasAccessKind::Read:
return "read";
case NoAliasAccessKind::Write:
return "write";
+ case NoAliasAccessKind::Deallocate:
+ return "deallocation";
}
llvm_unreachable("Unknown NoAliasAccessKind");
}
@@ -1467,7 +1441,7 @@ uint64_t Context::classifyNoAliasAccess(const NoAliasActivation &Activation,
for (uint64_t NodeID : Activation.Nodes) {
const auto It = NoAliasNodes.find(NodeID);
if (It == NoAliasNodes.end() || !It->second.Active ||
- It->second.Object != &MO)
+ (It->second.Object && It->second.Object != &MO))
continue;
if (isNoAliasAncestor(NodeID, AccessNode))
return NodeID;
@@ -1510,7 +1484,7 @@ bool Context::updateNoAliasAccesses(NoAliasActivation &Activation,
if (RunBegin == RunEnd)
return true;
- const bool IsWrite = Kind == NoAliasAccessKind::Write;
+ const bool IsWrite = Kind != NoAliasAccessKind::Read;
NoAliasAccessSummary New{AccessClass, false, IsWrite};
if (Old) {
New = *Old;
@@ -1615,9 +1589,13 @@ Pointer Context::createNoAliasPointer(const Pointer &Ptr,
if (!ExperimentalNoAlias || !ActivationID)
return Ptr;
- MemoryObject *MO = Ptr.getMemoryObject();
- if (!MO)
+ if (!Ptr.getMemoryObject() && !Ptr.provenance().isWildcard())
return Ptr;
+ // An unresolved wildcard can reach an allocation via arithmetic before its
+ // first access. Track foreign accesses from entry, without resolving or
+ // dereferencing the parameter.
+ MemoryObject *MO =
+ Ptr.provenance().isWildcard() ? nullptr : Ptr.getMemoryObject();
auto ActivationIt = NoAliasActivations.find(ActivationID);
assert(ActivationIt != NoAliasActivations.end() &&
@@ -1636,7 +1614,8 @@ Pointer Context::createNoAliasPointer(const Pointer &Ptr,
NoAliasNodes.try_emplace(NodeID, std::move(Node));
ActivationIt->second.Nodes.push_back(NodeID);
- auto &Activations = NoAliasActivationsByObject[MO];
+ auto &Activations =
+ MO ? NoAliasActivationsByObject[MO] : WildcardNoAliasActivations;
if (std::find(Activations.begin(), Activations.end(), ActivationID) ==
Activations.end())
Activations.push_back(ActivationID);
@@ -1644,7 +1623,7 @@ Pointer Context::createNoAliasPointer(const Pointer &Ptr,
std::string S;
raw_string_ostream OS(S);
OS << "created protector " << getNoAliasNodeName(NodeID) << " for "
- << getNoAliasObjectName(*MO) << " in "
+ << (MO ? getNoAliasObjectName(*MO) : "wildcard provenance") << " in "
<< getNoAliasActivationName(ActivationID) << " based on "
<< getNoAliasNodeName(Parent);
appendNoAliasEvent(std::move(S));
@@ -1657,12 +1636,20 @@ bool Context::accessNoAlias(MemoryObject &MO, uint64_t Offset, uint64_t Size,
return true;
auto It = NoAliasActivationsByObject.find(&MO);
- if (It == NoAliasActivationsByObject.end())
+ if (It == NoAliasActivationsByObject.end() &&
+ WildcardNoAliasActivations.empty())
return true;
+ SmallVector<uint64_t, 4> Activations(WildcardNoAliasActivations.begin(),
+ WildcardNoAliasActivations.end());
+ if (It != NoAliasActivationsByObject.end())
+ for (uint64_t ID : It->second)
+ if (!is_contained(Activations, ID))
+ Activations.push_back(ID);
+
const uint64_t End = Offset + Size;
uint32_t CheckedActivations = 0;
- for (uint64_t ActivationID : It->second) {
+ for (uint64_t ActivationID : Activations) {
auto ActivationIt = NoAliasActivations.find(ActivationID);
if (ActivationIt == NoAliasActivations.end())
continue;
@@ -1703,7 +1690,6 @@ void Context::endNoAliasActivation(uint64_t ActivationID) {
continue;
MemoryObject *MO = NodeIt->second.Object;
NodeIt->second.Active = false;
- tryEraseInactiveNoAliasNode(NodeID);
auto ObjectIt = NoAliasActivationsByObject.find(MO);
if (ObjectIt == NoAliasActivationsByObject.end())
continue;
@@ -1712,8 +1698,14 @@ void Context::endNoAliasActivation(uint64_t ActivationID) {
if (IDs.empty())
NoAliasActivationsByObject.erase(ObjectIt);
}
+ llvm::erase(WildcardNoAliasActivations, ActivationID);
appendNoAliasEvent("ended " + getNoAliasActivationName(ActivationID));
NoAliasActivations.erase(ActivationIt);
+ // A node ID may survive in SSA values or memory after its call returns.
+ // Reclaim the ancestry only when no active protector can distinguish it
+ // from the root. IDs are never reused, so later retags can safely use root.
+ if (NoAliasActivations.empty())
+ NoAliasNodes.clear();
}
SmallVector<std::string, 4> Context::takeNoAliasEvents() {
@@ -1726,23 +1718,13 @@ void Context::clearNoAliasState(const MemoryObject &MO) {
if (!ExperimentalNoAlias)
return;
- const auto It = NoAliasActivationsByObject.find(&MO);
- if (It == NoAliasActivationsByObject.end())
- return;
- SmallVector<uint64_t, 4> ActivationIDs(It->second.begin(), It->second.end());
- for (uint64_t ActivationID : ActivationIDs) {
- auto ActivationIt = NoAliasActivations.find(ActivationID);
- if (ActivationIt == NoAliasActivations.end())
- continue;
- for (uint64_t NodeID : ActivationIt->second.Nodes) {
- auto NodeIt = NoAliasNodes.find(NodeID);
- if (NodeIt != NoAliasNodes.end() && NodeIt->second.Object == &MO)
- NodeIt->second.Active = false;
- tryEraseInactiveNoAliasNode(NodeID);
- }
- ActivationIt->second.Accesses.erase(const_cast<MemoryObject *>(&MO));
- }
- NoAliasActivationsByObject.erase(It);
+ for (auto &[ID, Activation] : NoAliasActivations)
+ Activation.Accesses.erase(const_cast<MemoryObject *>(&MO));
+ // No valid access can use a concrete pointer to this allocation again.
+ // Also remove inactive nodes before their raw Object pointer can dangle.
+ NoAliasNodes.remove_if(
+ [&](const auto &Entry) { return Entry.second.Object == &MO; });
+ NoAliasActivationsByObject.erase(const_cast<MemoryObject *>(&MO));
}
} // namespace llvm::ubi
diff --git a/llvm/tools/llubi/lib/Context.h b/llvm/tools/llubi/lib/Context.h
index d4195402f75f36..028ceb77c81604 100644
--- a/llvm/tools/llubi/lib/Context.h
+++ b/llvm/tools/llubi/lib/Context.h
@@ -102,7 +102,7 @@ struct ProgramExitInfo {
}
};
-enum class NoAliasAccessKind { Read, Write };
+enum class NoAliasAccessKind { Read, Write, Deallocate };
class MemoryObject : public RefCountedBase<MemoryObject> {
uint64_t Address;
@@ -323,6 +323,8 @@ class Context {
/// they are used only to classify accesses in active function activations.
struct NoAliasNode {
uint64_t Parent = 0;
+ // Null for wildcard provenance: this node may access any allocation its
+ // provenance permits, including one reached by pointer arithmetic.
MemoryObject *Object = nullptr;
bool Active = false;
};
@@ -338,6 +340,7 @@ class Context {
DenseMap<uint64_t, NoAliasNode> NoAliasNodes;
DenseMap<uint64_t, NoAliasActivation> NoAliasActivations;
DenseMap<MemoryObject *, SmallVector<uint64_t, 2>> NoAliasActivationsByObject;
+ SmallVector<uint64_t, 2> WildcardNoAliasActivations;
// noalias-related diagnostics
std::string LastNoAliasError;
@@ -359,9 +362,6 @@ class Context {
/// Return whether \p Ancestor is on \p Descendant's noalias parent chain.
/// This relation defines whether an access is local to a protected node.
bool isNoAliasAncestor(uint64_t Ancestor, uint64_t Descendant) const;
- bool hasActiveNoAliasDescendant(uint64_t NodeID) const;
- /// Try to erase the node if it is inactive and has no active descendant.
- void tryEraseInactiveNoAliasNode(uint64_t NodeID);
static StringRef getNoAliasAccessKindName(NoAliasAccessKind Kind);
static std::string getNoAliasNodeName(uint64_t NodeID);
static std::string getNoAliasActivationName(uint64_t ActivationID);
@@ -517,7 +517,8 @@ class Context {
/// Apply an access to every active activation protecting \p MO.
bool accessNoAlias(MemoryObject &MO, uint64_t Offset, uint64_t Size,
uint64_t AccessNode, NoAliasAccessKind Kind);
- /// End an activation and discard its access summaries.
+ /// End an activation and discard its access summaries, preserving ancestry
+ /// for escaped pointers while any other activation remains active.
void endNoAliasActivation(uint64_t ActivationID);
StringRef getLastNoAliasError() const { return LastNoAliasError; }
SmallVector<std::string, 4> takeNoAliasEvents();
diff --git a/llvm/tools/llubi/lib/ExecutorBase.cpp b/llvm/tools/llubi/lib/ExecutorBase.cpp
index fc634830aa0892..c0b496a488a2af 100644
--- a/llvm/tools/llubi/lib/ExecutorBase.cpp
+++ b/llvm/tools/llubi/lib/ExecutorBase.cpp
@@ -13,30 +13,38 @@
#include "ExecutorBase.h"
namespace llvm::ubi {
+
+uint64_t retagNoAliasArguments(Context &Ctx, Function &F, CallBase *CallSite,
+ MutableArrayRef<AnyValue> Args) {
+ if (!Ctx.isExperimentalNoAliasEnabled())
+ return 0;
+ uint64_t Activation = 0;
+ for (auto [I, ArgValue] : enumerate(Args)) {
+ bool NoAlias = F.getAttributes().hasParamAttr(I, Attribute::NoAlias) ||
+ (CallSite && CallSite->getAttributes().hasParamAttr(
+ I, Attribute::NoAlias));
+ if (!NoAlias || !ArgValue.isPointer())
+ continue;
+ if (!Activation)
+ Activation = Ctx.beginNoAliasActivation();
+ ArgValue = Ctx.createNoAliasPointer(ArgValue.asPointer(), Activation);
+ }
+ return Activation;
+}
+
Frame::Frame(Context &Ctx, Function &F, CallBase *CallSite, Frame *LastFrame,
ArrayRef<AnyValue> Args, AnyValue &RetVal)
- : Func(F), LastFrame(LastFrame), CallSite(CallSite), Args(Args),
- RetVal(RetVal), TLI(Ctx.getTLIImpl(), &F) {
+ : Func(F), LastFrame(LastFrame), CallSite(CallSite),
+ Args(Args.begin(), Args.end()), RetVal(RetVal),
+ TLI(Ctx.getTLIImpl(), &F) {
assert((Args.size() == F.arg_size() ||
(F.isVarArg() && Args.size() >= F.arg_size())) &&
"Expected enough arguments to call the function.");
BB = &Func.getEntryBlock();
PC = BB->begin();
- for (Argument &Arg : F.args()) {
- AnyValue ArgValue = Args[Arg.getArgNo()];
- // Retag only callee-visible noalias pointer parameters. This creates the
- // protected node for the dynamic call frame without changing the normal
- // provenance carried by the pointer.
- if (Ctx.isExperimentalNoAliasEnabled() && Arg.hasNoAliasAttr() &&
- Arg.getType()->isPointerTy() && !ArgValue.isPoison() &&
- ArgValue.asPointer().getMemoryObject()) {
- if (!NoAliasActivation)
- NoAliasActivation = Ctx.beginNoAliasActivation();
- ArgValue =
- Ctx.createNoAliasPointer(ArgValue.asPointer(), NoAliasActivation);
- }
- ValueMap[&Arg] = std::move(ArgValue);
- }
+ NoAliasActivation = retagNoAliasArguments(Ctx, F, CallSite, this->Args);
+ for (Argument &Arg : F.args())
+ ValueMap[&Arg] = this->Args[Arg.getArgNo()];
}
DiagnosticReporter ExecutorBase::reportImmediateUB() {
@@ -129,9 +137,24 @@ ExecutorBase::verifyMemAccess(const Pointer &Ptr, uint64_t AccessSize,
return {};
}
+ if (!verifyNoAliasAccess(*MO, Offset.getZExtValue(), AccessSize, Ptr,
+ IsStore ? NoAliasAccessKind::Write
+ : NoAliasAccessKind::Read))
+ return {};
return {MO, Offset.getZExtValue()};
}
+bool ExecutorBase::verifyNoAliasAccess(MemoryObject &MO, uint64_t Offset,
+ uint64_t Size, const Pointer &Ptr,
+ NoAliasAccessKind Kind) {
+ bool Valid =
+ Ctx.accessNoAlias(MO, Offset, Size, Ptr.getNoAliasNodeID(), Kind);
+ flushNoAliasEvents();
+ if (!Valid)
+ reportImmediateUB() << Ctx.getLastNoAliasError();
+ return Valid;
+}
+
AnyValue ExecutorBase::load(const AnyValue &Ptr, Align Alignment, Type *ValTy,
bool NoUndef) {
if (Ptr.isPoison()) {
@@ -149,17 +172,6 @@ AnyValue ExecutorBase::load(const AnyValue &Ptr, Align Alignment, Type *ValTy,
if (NoUndef && ContainsUndefinedBits)
reportImmediateUB() << "The value loaded contains undefined bits.";
- // Run noalias after ordinary memory validity checks so diagnostics report
- // aliasing only for otherwise valid concrete accesses.
- if (const uint64_t AccessSize = Ctx.getEffectiveTypeStoreSize(ValTy);
- !Ctx.accessNoAlias(*MO, Offset, AccessSize, PtrVal.getNoAliasNodeID(),
- NoAliasAccessKind::Read)) {
- flushNoAliasEvents();
- reportImmediateUB() << Ctx.getLastNoAliasError();
- return AnyValue::getPoisonValue(Ctx, ValTy);
- }
- flushNoAliasEvents();
-
return Res;
}
return AnyValue::getPoisonValue(Ctx, ValTy);
@@ -176,14 +188,6 @@ void ExecutorBase::store(const AnyValue &Ptr, Align Alignment,
PtrVal, Ctx.getEffectiveTypeStoreSize(ValTy), Alignment,
/*IsStore=*/true);
MO) {
- if (const uint64_t AccessSize = Ctx.getEffectiveTypeStoreSize(ValTy);
- !Ctx.accessNoAlias(*MO, Offset, AccessSize, PtrVal.getNoAliasNodeID(),
- NoAliasAccessKind::Write)) {
- flushNoAliasEvents();
- reportImmediateUB() << Ctx.getLastNoAliasError();
- return;
- }
- flushNoAliasEvents();
Ctx.store(*MO, Offset, Val, ValTy);
}
}
diff --git a/llvm/tools/llubi/lib/ExecutorBase.h b/llvm/tools/llubi/lib/ExecutorBase.h
index 370808d77814b0..b514f7a17dd0df 100644
--- a/llvm/tools/llubi/lib/ExecutorBase.h
+++ b/llvm/tools/llubi/lib/ExecutorBase.h
@@ -22,6 +22,11 @@
namespace llvm::ubi {
+/// Apply the parameter guarantees of this invocation to its callee-visible
+/// arguments, creating at most one dynamic noalias activation.
+uint64_t retagNoAliasArguments(Context &Ctx, Function &F, CallBase *CallSite,
+ MutableArrayRef<AnyValue> Args);
+
enum class FrameState {
// It is about to enter the function.
// Valid transition:
@@ -48,7 +53,7 @@ struct Frame {
Function &Func;
Frame *LastFrame;
CallBase *CallSite;
- ArrayRef<AnyValue> Args;
+ SmallVector<AnyValue, 4> Args;
AnyValue &RetVal;
TargetLibraryInfo TLI;
@@ -105,13 +110,18 @@ class ExecutorBase {
void flushNoAliasEvents();
- /// Check if the upcoming memory access is valid. Returns the resolved memory
- /// object and offset if it is valid.
+ /// Validate a memory access and record its noalias effect. Returns the
+ /// resolved memory object and offset if it is valid. Call this only for
+ /// actual accesses, not speculative bounds or provenance queries.
std::pair<MemoryObject *, uint64_t> verifyMemAccess(const Pointer &Ptr,
uint64_t AccessSize,
Align Alignment,
bool IsStore);
+ /// Record an otherwise valid access, including a deallocation.
+ bool verifyNoAliasAccess(MemoryObject &MO, uint64_t Offset, uint64_t Size,
+ const Pointer &Ptr, NoAliasAccessKind Kind);
+
AnyValue load(const AnyValue &Ptr, Align Alignment, Type *ValTy,
bool NoUndef);
void store(const AnyValue &Ptr, Align Alignment, const AnyValue &Val,
diff --git a/llvm/tools/llubi/lib/Interpreter.cpp b/llvm/tools/llubi/lib/Interpreter.cpp
index e15f4f0b197e4a..29793a3af425b1 100644
--- a/llvm/tools/llubi/lib/Interpreter.cpp
+++ b/llvm/tools/llubi/lib/Interpreter.cpp
@@ -2164,12 +2164,23 @@ class InstExecutor : public InstVisitor<InstExecutor, void>,
}
CurrentFrame->ResolvedCallee = Callee;
+ // Intrinsics and library calls have no Frame, but their parameter
+ // guarantees (including call-site-only attributes) cover their effects.
+ uint64_t NoAliasActivation = 0;
+ if (Callee->isDeclaration()) {
+ NoAliasActivation = retagNoAliasArguments(Ctx, *Callee, &CB, CalleeArgs);
+ flushNoAliasEvents();
+ }
if (Callee->isIntrinsic()) {
CurrentFrame->CalleeRetVal = callIntrinsic(CB, CalleeArgs);
+ Ctx.endNoAliasActivation(NoAliasActivation);
+ flushNoAliasEvents();
returnFromCallee();
return;
} else if (Callee->isDeclaration()) {
CurrentFrame->CalleeRetVal = callLibFunc(CB, Callee, CalleeArgs);
+ Ctx.endNoAliasActivation(NoAliasActivation);
+ flushNoAliasEvents();
returnFromCallee();
return;
} else {
diff --git a/llvm/tools/llubi/lib/Library.cpp b/llvm/tools/llubi/lib/Library.cpp
index c3452b8af92c01..82e9caa17ee1a6 100644
--- a/llvm/tools/llubi/lib/Library.cpp
+++ b/llvm/tools/llubi/lib/Library.cpp
@@ -158,6 +158,10 @@ AnyValue Library::executeFree(ArrayRef<AnyValue> Args) {
// allocation family (malloc, calloc, etc.) is freed with a different free
// function comes from a different family (C++ delete, etc.)
+ if (!Executor.verifyNoAliasAccess(*Obj, 0, Obj->getSize(), Ptr,
+ NoAliasAccessKind::Deallocate))
+ return AnyValue();
+
if (!Ctx.free(*Obj)) {
Executor.reportImmediateUB()
<< "freeing an invalid pointer at 0x"
>From 724d50de72f828836dc55659c2474b1b29f68710 Mon Sep 17 00:00:00 2001
From: Zhige Chen <zhigec_cpp at outlook.com>
Date: Sat, 26 Sep 2026 17:57:35 +0800
Subject: [PATCH 5/5] [llubi] Format code
---
llvm/tools/llubi/lib/Value.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/llvm/tools/llubi/lib/Value.h b/llvm/tools/llubi/lib/Value.h
index 739574e698d0b6..c5b6d5d6573a5d 100644
--- a/llvm/tools/llubi/lib/Value.h
+++ b/llvm/tools/llubi/lib/Value.h
@@ -146,7 +146,8 @@ struct Byte {
static_cast<uint8_t>(Value << Shift),
static_cast<uint8_t>(TagMask << Shift),
static_cast<uint8_t>(TagValue << Shift),
- static_cast<uint8_t>(NoAliasMask << Shift), NoAliasNode};
+ static_cast<uint8_t>(NoAliasMask << Shift),
+ NoAliasNode};
}
bool areHighBitsZExtd(uint8_t BitsFrom) const {
More information about the llvm-commits
mailing list