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[asan] Fix a false positive ODR violation due to LTO ConstantMerge pass [llvm part, take 3]

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This fixes a false positive ODR violation that is reported by ASan when using LTO. In cases, where two constant globals have the same value, LTO will merge them, which breaks ASan's ODR detection.

Differential Revision: https://reviews.llvm.org/D43959

llvm-svn: 327061
This commit is contained in:
Kuba Mracek 2018-03-08 21:02:18 +00:00
parent 0b5103198a
commit 0d947d71f9
2 changed files with 40 additions and 0 deletions
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10
lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -2158,6 +2158,16 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool
Initializers[i] = Initializer;
}
// Add instrumented globals to llvm.compiler.used list to avoid LTO from
// ConstantMerge'ing them.
SmallVector<GlobalValue *, 16> GlobalsToAddToUsedList;
for (size_t i = 0; i < n; i++) {
GlobalVariable *G = NewGlobals[i];
if (G->getName().empty()) continue;
GlobalsToAddToUsedList.push_back(G);
}
appendToCompilerUsed(M, ArrayRef<GlobalValue *>(GlobalsToAddToUsedList));
std::string ELFUniqueModuleId =
(UseGlobalsGC && TargetTriple.isOSBinFormatELF()) ? getUniqueModuleId(&M)
: "";

30
test/Instrumentation/AddressSanitizer/global_lto_merge.ll Normal file
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@ -0,0 +1,30 @@
; RUN: opt < %s -asan -asan-module -S | FileCheck %s
; RUN: opt < %s -asan -asan-module -constmerge -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.11.0"
%struct = type { i64, i64 }
@a = private unnamed_addr constant %struct { i64 16, i64 16 }, align 8
@b = private unnamed_addr constant %struct { i64 16, i64 16 }, align 8
; CHECK: @a = {{.*}} %struct
; CHECK: @b = {{.*}} %struct
; CHECK: @llvm.compiler.used =
; CHECK-SAME: i8* bitcast ({ %struct, [48 x i8] }* @a to i8*)
; CHECK-SAME: i8* bitcast ({ %struct, [48 x i8] }* @b to i8*)
define i32 @main(i32, i8** nocapture readnone) {
%3 = alloca %struct, align 8
%4 = alloca %struct, align 8
%5 = bitcast %struct* %3 to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %5, i8* bitcast (%struct* @a to i8*), i64 16, i32 8, i1 false)
%6 = bitcast %struct* %4 to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %6, i8* bitcast (%struct* @b to i8*), i64 16, i32 8, i1 false)
call void asm sideeffect "", "r,r,~{dirflag},~{fpsr},~{flags}"(%struct* nonnull %3, %struct* nonnull %4)
ret i32 0
}
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1)