[llvm] [hwasan] Add hwasan-all-globals option (PR #149621)
via llvm-commits
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Wed Jul 30 09:23:51 PDT 2025
https://github.com/shuffle2 updated https://github.com/llvm/llvm-project/pull/149621
>From 98a5661935969d177e641960db49bb6c28bd9531 Mon Sep 17 00:00:00 2001
From: Shawn Hoffman <godisgovernment at gmail.com>
Date: Fri, 18 Jul 2025 15:56:28 -0700
Subject: [PATCH] [hwasan] Add hwasan-all-globals option hwasan-globals does
not instrument globals with custom sections, because existing code may use
__start_/__stop_ symbols to iterate over globals in such a way which will
cause hwasan assertions.
Introduce new hwasan-all-globals option, which instruments all
user-defined globals (but not those globals which are generated by
the hwasan instrumentation itself), including those with custom sections.
---
.../Instrumentation/HWAddressSanitizer.cpp | 30 ++++++++++++++-----
.../HWAddressSanitizer/globals.ll | 24 ++++++++-------
2 files changed, 37 insertions(+), 17 deletions(-)
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 4e5a8d123e084..fa668c701ccf5 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -160,6 +160,16 @@ static cl::opt<bool> ClGenerateTagsWithCalls(
static cl::opt<bool> ClGlobals("hwasan-globals", cl::desc("Instrument globals"),
cl::Hidden, cl::init(false));
+static cl::opt<bool> ClAllGlobals(
+ "hwasan-all-globals",
+ cl::desc(
+ "Instrument globals, even those within user-defined sections. Warning: "
+ "This may break existing code which walks globals via linker-generated "
+ "symbols, expects certain globals to be contiguous with each other, or "
+ "makes other assumptions which are invalidated by HWASan "
+ "instrumentation."),
+ cl::Hidden, cl::init(false));
+
static cl::opt<int> ClMatchAllTag(
"hwasan-match-all-tag",
cl::desc("don't report bad accesses via pointers with this tag"),
@@ -681,11 +691,11 @@ void HWAddressSanitizer::initializeModule() {
!CompileKernel && !UsePageAliases && optOr(ClGlobals, NewRuntime);
if (!CompileKernel) {
- createHwasanCtorComdat();
-
if (InstrumentGlobals)
instrumentGlobals();
+ createHwasanCtorComdat();
+
bool InstrumentPersonalityFunctions =
optOr(ClInstrumentPersonalityFunctions, NewRuntime);
if (InstrumentPersonalityFunctions)
@@ -1772,11 +1782,17 @@ void HWAddressSanitizer::instrumentGlobals() {
if (GV.hasCommonLinkage())
continue;
- // Globals with custom sections may be used in __start_/__stop_ enumeration,
- // which would be broken both by adding tags and potentially by the extra
- // padding/alignment that we insert.
- if (GV.hasSection())
- continue;
+ if (ClAllGlobals) {
+ // Avoid intrumenting intrinsic global variables.
+ if (GV.getSection() == "llvm.metadata")
+ continue;
+ } else {
+ // Globals with custom sections may be used in __start_/__stop_
+ // enumeration, which would be broken both by adding tags and potentially
+ // by the extra padding/alignment that we insert.
+ if (GV.hasSection())
+ continue;
+ }
Globals.push_back(&GV);
}
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/globals.ll b/llvm/test/Instrumentation/HWAddressSanitizer/globals.ll
index f5ae1c0f80497..4c2852391d534 100644
--- a/llvm/test/Instrumentation/HWAddressSanitizer/globals.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/globals.ll
@@ -1,16 +1,11 @@
-; RUN: opt < %s -S -passes=hwasan -mtriple=aarch64--linux-android29 | FileCheck --check-prefixes=CHECK,CHECK29 %s
-; RUN: opt < %s -S -passes=hwasan -mtriple=aarch64--linux-android30 | FileCheck --check-prefixes=CHECK,CHECK30 %s
+; RUN: opt < %s -S -passes=hwasan -mtriple=aarch64--linux-android29 | FileCheck --check-prefixes=CHECK,CHECK29,NOALLGLOBALS %s
+; RUN: opt < %s -S -passes=hwasan -mtriple=aarch64--linux-android30 | FileCheck --check-prefixes=CHECK,CHECK30,NOALLGLOBALS %s
+; RUN: opt < %s -S -passes=hwasan -mtriple=riscv64-unknown-elf -hwasan-globals=1 -hwasan-all-globals=1 | FileCheck --check-prefixes=CHECK,CHECK30,ALLGLOBALS %s
; CHECK29: @four = global
; CHECK: @specialcaselisted = global i16 2, no_sanitize_hwaddress
-; CHECK: @insection = global i16 2, section "custom"
-; CHECK: @__start_hwasan_globals = external hidden constant [0 x i8]
-; CHECK: @__stop_hwasan_globals = external hidden constant [0 x i8]
-
-; CHECK: @hwasan.note = private constant { i32, i32, i32, [8 x i8], i32, i32 } { i32 8, i32 8, i32 3, [8 x i8] c"LLVM\00\00\00\00", i32 trunc (i64 sub (i64 ptrtoint (ptr @__start_hwasan_globals to i64), i64 ptrtoint (ptr @hwasan.note to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @__stop_hwasan_globals to i64), i64 ptrtoint (ptr @hwasan.note to i64)) to i32) }, section ".note.hwasan.globals", comdat($hwasan.module_ctor), align 4
-
-; CHECK: @hwasan.dummy.global = private constant [0 x i8] zeroinitializer, section "hwasan_globals", comdat($hwasan.module_ctor), !associated [[NOTE:![0-9]+]]
+; NOALLGLOBALS: @insection = global i16 2, section "custom"
; CHECK30: @four.hwasan = private global { i32, [12 x i8] } { i32 1, [12 x i8] c"\00\00\00\00\00\00\00\00\00\00\00\AC" }, align 16
; CHECK30: @four.hwasan.descriptor = private constant { i32, i32 } { i32 trunc (i64 sub (i64 ptrtoint (ptr @four.hwasan to i64), i64 ptrtoint (ptr @four.hwasan.descriptor to i64)) to i32), i32 -1409286140 }, section "hwasan_globals", !associated [[FOUR:![0-9]+]]
@@ -22,14 +17,23 @@
; CHECK30: @huge.hwasan.descriptor = private constant { i32, i32 } { i32 trunc (i64 sub (i64 ptrtoint (ptr @huge.hwasan to i64), i64 ptrtoint (ptr @huge.hwasan.descriptor to i64)) to i32), i32 -1358954512 }, section "hwasan_globals", !associated [[HUGE:![0-9]+]]
; CHECK30: @huge.hwasan.descriptor.1 = private constant { i32, i32 } { i32 trunc (i64 add (i64 sub (i64 ptrtoint (ptr @huge.hwasan to i64), i64 ptrtoint (ptr @huge.hwasan.descriptor.1 to i64)), i64 16777200) to i32), i32 -1375731680 }, section "hwasan_globals", !associated [[HUGE]]
+; ALLGLOBALS: @insection.hwasan = private global { i16, [14 x i8] } { i16 2, [14 x i8] c"\00\00\00\00\00\00\00\00\00\00\00\00\00\AF" }, section "custom", align 16
+
+; CHECK: @__start_hwasan_globals = external hidden constant [0 x i8]
+; CHECK: @__stop_hwasan_globals = external hidden constant [0 x i8]
+
+; CHECK: @hwasan.note = private constant { i32, i32, i32, [8 x i8], i32, i32 } { i32 8, i32 8, i32 3, [8 x i8] c"LLVM\00\00\00\00", i32 trunc (i64 sub (i64 ptrtoint (ptr @__start_hwasan_globals to i64), i64 ptrtoint (ptr @hwasan.note to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @__stop_hwasan_globals to i64), i64 ptrtoint (ptr @hwasan.note to i64)) to i32) }, section ".note.hwasan.globals", comdat($hwasan.module_ctor), align 4
+
+; CHECK: @hwasan.dummy.global = private constant [0 x i8] zeroinitializer, section "hwasan_globals", comdat($hwasan.module_ctor), !associated [[NOTE:![0-9]+]]
+
; CHECK30: @four = alias i32, inttoptr (i64 add (i64 ptrtoint (ptr @four.hwasan to i64), i64 -6052837899185946624) to ptr)
; CHECK30: @sixteen = alias [16 x i8], inttoptr (i64 add (i64 ptrtoint (ptr @sixteen.hwasan to i64), i64 -5980780305148018688) to ptr)
; CHECK30: @huge = alias [16777232 x i8], inttoptr (i64 add (i64 ptrtoint (ptr @huge.hwasan to i64), i64 -5908722711110090752) to ptr)
-; CHECK: [[NOTE]] = !{ptr @hwasan.note}
; CHECK30: [[FOUR]] = !{ptr @four.hwasan}
; CHECK30: [[SIXTEEN]] = !{ptr @sixteen.hwasan}
; CHECK30: [[HUGE]] = !{ptr @huge.hwasan}
+; CHECK: [[NOTE]] = !{ptr @hwasan.note}
source_filename = "foo"
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