[libcxx-commits] [flang] [libcxx] [clang] [llvm] [lld] [libcxxabi] [lldb] [libc] [msan] Unpoison indirect outputs for userspace using llvm.memset.* (PR #79924)
Fangrui Song via libcxx-commits
libcxx-commits at lists.llvm.org
Tue Jan 30 11:14:26 PST 2024
https://github.com/MaskRay updated https://github.com/llvm/llvm-project/pull/79924
>From 07043d27155ffd89e23b64c77a99880b2fa57e57 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Mon, 29 Jan 2024 17:02:18 -0800
Subject: [PATCH 1/2] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
=?UTF-8?q?itial=20version?=
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Created using spr 1.3.4
---
.../Instrumentation/MemorySanitizer.cpp | 5 ++++-
.../MemorySanitizer/msan_asm_conservative.ll | 16 ++++++++--------
2 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 2b697557d8a9..0806d7a5b145 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -4559,9 +4559,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
} else {
// ElemTy, derived from elementtype(), does not encode the alignment of
// the pointer. Conservatively assume that the shadow memory is unaligned.
+ // Avoid StoreInst as SizeVal may be large, expanding to many
+ // instructions.
auto [ShadowPtr, _] =
getShadowOriginPtrUserspace(Operand, IRB, IRB.getInt8Ty(), Align(1));
- IRB.CreateAlignedStore(getCleanShadow(ElemTy), ShadowPtr, Align(1));
+ IRB.CreateMemSet(ShadowPtr, ConstantInt::getNullValue(IRB.getInt8Ty()),
+ SizeVal, Align(1));
}
}
diff --git a/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll b/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll
index 894f76b9b8d3..86ca697ed9a4 100644
--- a/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll
+++ b/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll
@@ -177,8 +177,8 @@ entry:
}
; CHECK-LABEL: @f_2i_2o_mem
-; USER-CONS: store i32 0, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @id1 to i64), i64 87960930222080) to ptr), align 1
-; USER-CONS: store i32 0, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @id2 to i64), i64 87960930222080) to ptr), align 1
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @id1 to i64), i64 87960930222080) to ptr), i8 0, i64 4, i1 false)
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @id2 to i64), i64 87960930222080) to ptr), i8 0, i64 4, i1 false)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@id1{{.*}}, i64 4)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@id2{{.*}}, i64 4)
; CHECK: call void asm "", "=*m,=*m,*m,*m,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(i32) @id1, ptr elementtype(i32) @id2, ptr elementtype(i32) @is1, ptr elementtype(i32) @is2)
@@ -196,7 +196,7 @@ entry:
; CHECK-LABEL: @f_1i_1o_memreg
; CHECK: [[IS1_F7:%.*]] = load i32, ptr @is1, align 4
-; USER-CONS: store i32 0, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @id1 to i64), i64 87960930222080) to ptr), align 1
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @id1 to i64), i64 87960930222080) to ptr), i8 0, i64 4, i1 false)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@id1{{.*}}, i64 4)
; CHECK: call void @__msan_warning
; CHECK: call i32 asm "", "=r,=*m,r,*m,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(i32) @id1, i32 [[IS1_F7]], ptr elementtype(i32) @is1)
@@ -215,7 +215,7 @@ entry:
}
; CHECK-LABEL: @f_3o_reg_mem_reg
-; USER-CONS: store i32 0, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @id2 to i64), i64 87960930222080) to ptr), align 1
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @id2 to i64), i64 87960930222080) to ptr), i8 0, i64 4, i1 false)
; CHECK-CONS: call void @__msan_instrument_asm_store(ptr @id2, i64 4)
; CHECK: call { i32, i32 } asm "", "=r,=*m,=r,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(i32) @id2)
@@ -240,7 +240,7 @@ entry:
; CHECK: [[PAIR1_F9:%.*]] = load {{.*}} @pair1
; CHECK: [[C1_F9:%.*]] = load {{.*}} @c1
; CHECK: [[MEMCPY_S1_F9:%.*]] = load {{.*}} @memcpy_s1
-; USER-CONS: store { i32, i32 } zeroinitializer, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @pair2 to i64), i64 87960930222080) to ptr), align 1
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @pair2 to i64), i64 87960930222080) to ptr), i8 0, i64 8, i1 false)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@pair2{{.*}}, i64 8)
; CHECK: call void @__msan_warning
; KMSAN: call void @__msan_warning
@@ -257,9 +257,9 @@ entry:
}
; CHECK-LABEL: @f_3i_3o_complex_mem
-; USER-CONS: store { i32, i32 } zeroinitializer, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @pair2 to i64), i64 87960930222080) to ptr), align 1
-; USER-CONS-NEXT: store i8 0, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @c2 to i64), i64 87960930222080) to ptr), align 1
-; USER-CONS-NEXT: store i64 0, ptr inttoptr (i64 xor (i64 ptrtoint (ptr @memcpy_d1 to i64), i64 87960930222080) to ptr), align 1
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @pair2 to i64), i64 87960930222080) to ptr), i8 0, i64 8, i1 false)
+; USER-CONS-NEXT: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @c2 to i64), i64 87960930222080) to ptr), i8 0, i64 1, i1 false)
+; USER-CONS-NEXT: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @memcpy_d1 to i64), i64 87960930222080) to ptr), i8 0, i64 8, i1 false)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@pair2{{.*}}, i64 8)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@c2{{.*}}, i64 1)
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@memcpy_d1{{.*}}, i64 8)
>From d4d4c73fad28e8095a98a6690e89abd95ecf10a6 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Tue, 30 Jan 2024 11:14:17 -0800
Subject: [PATCH 2/2] improve test and comment
Created using spr 1.3.4
---
llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp | 2 +-
.../MemorySanitizer/msan_asm_conservative.ll | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 2d90c92c7624..46b9181c8922 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -4563,7 +4563,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// instructions.
auto [ShadowPtr, _] =
getShadowOriginPtrUserspace(Operand, IRB, IRB.getInt8Ty(), Align(1));
- if (Size < 32)
+ if (Size <= 32)
IRB.CreateAlignedStore(getCleanShadow(ElemTy), ShadowPtr, Align(1));
else
IRB.CreateMemSet(ShadowPtr, ConstantInt::getNullValue(IRB.getInt8Ty()),
diff --git a/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll b/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll
index e14012e5211c..2a643e12a487 100644
--- a/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll
+++ b/llvm/test/Instrumentation/MemorySanitizer/msan_asm_conservative.ll
@@ -14,7 +14,7 @@ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%struct.pair = type { i32, i32 }
-%struct.large = type { [9 x i32] }
+%struct.large = type { [33 x i8] }
@id1 = common dso_local global i32 0, align 4
@is1 = common dso_local global i32 0, align 4
@@ -266,6 +266,7 @@ entry:
; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@memcpy_d1{{.*}}, i64 8)
; CHECK: call void asm "", "=*m,=*m,=*m,*m,*m,*m,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(%struct.pair) @pair2, ptr elementtype(i8) @c2, ptr elementtype(ptr) @memcpy_d1, ptr elementtype(%struct.pair) @pair1, ptr elementtype(i8) @c1, ptr elementtype(ptr) @memcpy_s1)
+; Use memset when the size is larger.
define dso_local void @f_1i_1o_mem_large() sanitize_memory {
entry:
%0 = call i32 asm "", "=r,=*m,*m,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(%struct.large) @large, ptr elementtype(%struct.large) @large)
@@ -273,8 +274,8 @@ entry:
ret void
}
; CHECK-LABEL: @f_1i_1o_mem_large(
-; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @large to i64), i64 87960930222080) to ptr), i8 0, i64 36, i1 false)
-; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@large{{.*}}, i64 36)
+; USER-CONS: call void @llvm.memset.p0.i64(ptr align 1 inttoptr (i64 xor (i64 ptrtoint (ptr @large to i64), i64 87960930222080) to ptr), i8 0, i64 33, i1 false)
+; CHECK-CONS: call void @__msan_instrument_asm_store({{.*}}@large{{.*}}, i64 33)
; CHECK: call i32 asm "", "=r,=*m,*m,~{dirflag},~{fpsr},~{flags}"(ptr elementtype(%struct.large) @large, ptr elementtype(%struct.large) @large)
; A simple asm goto construct to check that callbr is handled correctly:
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