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[asan] change the coverage collection scheme so that we can easily emit coverage for the entire process as a single bit set, and if coverage_bitset=1 actually emit that bitset

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224789 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Kostya Serebryany
2014-12-23 22:32:17 +00:00
parent c9e5247ea7
commit b69d796590
4 changed files with 33 additions and 21 deletions
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36
lib/Transforms/Instrumentation/SanitizerCoverage.cpp
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@@ -10,10 +10,10 @@
// Coverage instrumentation that works with AddressSanitizer
// and potentially with other Sanitizers.
//
// We create a Guard boolean variable with the same linkage
// We create a Guard variable with the same linkage
// as the function and inject this code into the entry block (CoverageLevel=1)
// or all blocks (CoverageLevel>=2):
// if (Guard) {
// if (Guard < 0) {
// __sanitizer_cov(&Guard);
// }
// The accesses to Guard are atomic. The rest of the logic is
@@ -112,6 +112,8 @@ class SanitizerCoverageModule : public ModulePass {
Type *IntptrTy;
LLVMContext *C;
SmallVector<Constant *, 16> Guards;
int CoverageLevel;
};
@@ -134,6 +136,8 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
IntptrTy = Type::getIntNTy(*C, DLP->getDataLayout().getPointerSizeInBits());
Type *VoidTy = Type::getVoidTy(*C);
IRBuilder<> IRB(*C);
Type *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
Type *Int32PtrPtrTy = PointerType::getUnqual(Int32PtrTy);
Function *CtorFunc =
Function::Create(FunctionType::get(VoidTy, false),
@@ -142,11 +146,12 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
appendToGlobalCtors(M, CtorFunc, kSanCtorAndDtorPriority);
SanCovFunction = checkInterfaceFunction(
M.getOrInsertFunction(kSanCovName, VoidTy, IRB.getInt8PtrTy(), nullptr));
M.getOrInsertFunction(kSanCovName, VoidTy, Int32PtrTy, nullptr));
SanCovIndirCallFunction = checkInterfaceFunction(M.getOrInsertFunction(
kSanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr));
SanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction(
kSanCovModuleInitName, Type::getVoidTy(*C), IntptrTy, nullptr));
SanCovModuleInit = checkInterfaceFunction(
M.getOrInsertFunction(kSanCovModuleInitName, Type::getVoidTy(*C),
Int32PtrPtrTy, 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),
@@ -163,9 +168,15 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
for (auto &F : M)
runOnFunction(F);
ArrayType *ArrayOfInt32PtrTy = ArrayType::get(Int32PtrTy, Guards.size());
IRB.SetInsertPoint(CtorFunc->getEntryBlock().getTerminator());
IRB.CreateCall(SanCovModuleInit,
ConstantInt::get(IntptrTy, SanCovFunction->getNumUses()));
GlobalVariable *AllGuards = new GlobalVariable(
M, ArrayOfInt32PtrTy, false, GlobalVariable::InternalLinkage,
ConstantArray::get(ArrayOfInt32PtrTy, Guards), "");
assert(SanCovFunction->getNumUses() == Guards.size());
IRB.CreateCall2(SanCovModuleInit,
IRB.CreatePointerCast(AllGuards, Int32PtrPtrTy),
ConstantInt::get(IntptrTy, Guards.size()));
return true;
}
@@ -271,16 +282,16 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F,
: IP->getDebugLoc();
IRBuilder<> IRB(IP);
IRB.SetCurrentDebugLocation(EntryLoc);
Type *Int8Ty = IRB.getInt8Ty();
Type *Int32Ty = IRB.getInt32Ty();
GlobalVariable *Guard = new GlobalVariable(
*F.getParent(), Int8Ty, false, GlobalValue::PrivateLinkage,
Constant::getNullValue(Int8Ty), "__sancov_gen_cov_" + F.getName());
*F.getParent(), Int32Ty, false, GlobalValue::PrivateLinkage,
Constant::getNullValue(Int32Ty), "__sancov_gen_cov_" + F.getName());
LoadInst *Load = IRB.CreateLoad(Guard);
Load->setAtomic(Monotonic);
Load->setAlignment(1);
Load->setAlignment(4);
Load->setMetadata(F.getParent()->getMDKindID("nosanitize"),
MDNode::get(*C, None));
Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), Load);
Value *Cmp = IRB.CreateICmpSGE(Constant::getNullValue(Int32Ty), Load);
Instruction *Ins = SplitBlockAndInsertIfThen(
Cmp, IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
IRB.SetInsertPoint(Ins);
@@ -288,6 +299,7 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F,
// __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
IRB.CreateCall(SanCovFunction, Guard);
IRB.CreateCall(EmptyAsm); // Avoids callback merge.
Guards.push_back(Guard); // Save the guard for later.
}
char SanitizerCoverageModule::ID = 0;