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[sanitizer] prevent function call merging for sanitizer-coverage callbacks 

llvm-svn: 224372
This commit is contained in:
Kostya Serebryany 2014-12-16 21:24:15 +00:00
parent 92c14bb2ff
commit 7376294086
2 changed files with 11 additions and 0 deletions
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7
llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
View File

@ -37,6 +37,7 @@
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
@ -107,6 +108,7 @@ class SanitizerCoverageModule : public ModulePass {
Function *SanCovIndirCallFunction;
Function *SanCovModuleInit;
Function *SanCovTraceEnter, *SanCovTraceBB;
InlineAsm *EmptyAsm;
Type *IntptrTy;
LLVMContext *C;
@ -146,6 +148,10 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
SanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction(
kSanCovModuleInitName, Type::getVoidTy(*C), IntptrTy, nullptr));
SanCovModuleInit->setLinkage(Function::ExternalLinkage);
// We insert an empty inline asm after cov callbacks to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
/*hasSideEffects=*/true);
if (ClExperimentalTracing) {
SanCovTraceEnter = checkInterfaceFunction(
@ -283,6 +289,7 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F,
IRB.SetCurrentDebugLocation(EntryLoc);
// __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
IRB.CreateCall(SanCovFunction, Guard);
IRB.CreateCall(EmptyAsm); // Avoids callback merge.
}
char SanitizerCoverageModule::ID = 0;

4
llvm/test/Instrumentation/SanitizerCoverage/coverage.ll
View File

@ -37,6 +37,7 @@ entry:
; CHECK1: %1 = icmp eq i8 0, %0
; CHECK1: br i1 %1, label %2, label %3
; CHECK1: call void @__sanitizer_cov(i8*{{.*}})
; CHECK1: call void asm sideeffect "", ""()
; CHECK1-NOT: call void @__sanitizer_cov
; CHECK1: ret void
@ -48,8 +49,11 @@ entry:
; CHECK2-LABEL: define void @foo
; CHECK2: call void @__sanitizer_cov
; CHECK2: call void asm sideeffect "", ""()
; CHECK2: call void @__sanitizer_cov
; CHECK2: call void asm sideeffect "", ""()
; CHECK2: call void @__sanitizer_cov
; CHECK2: call void asm sideeffect "", ""()
; CHECK2-NOT: call void @__sanitizer_cov
; CHECK2: ret void