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[sanitizer coverage] Fix Instrumentation to work on Windows. 

On Windows, the symbols "___stop___sancov_guards" and "___start___sancov_guards"
are not defined automatically. So, we need to take a different approach.
We define 3 sections:

 Section ".SCOV$A" will only hold a variable ___start___sancov_guard.
 Section ".SCOV$M" will hold the main data.
 Section ".SCOV$Z" will only hold a variable ___stop___sancov_guards.

When linking, they will be merged sorted by the characters after the $, so we
can use the pointers of the variables ___[start|stop]___sancov_guard to know the
actual range of addresses of that section.

In this diff, I updated instrumentation to include all the guard arrays in
section ".SCOV$M".

Differential Revision: https://reviews.llvm.org/D28434

llvm-svn: 293987
This commit is contained in:
Marcos Pividori 2017-02-03 01:08:06 +00:00
parent 37c22a3ecb
commit db5a565514
1 changed files with 29 additions and 21 deletions
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50
llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
View File

@ -138,24 +138,6 @@ static cl::opt<bool> ClUse8bitCounters("sanitizer-coverage-8bit-counters",
cl::desc("Experimental 8-bit counters"),
cl::Hidden, cl::init(false));
static StringRef getSanCovTracePCGuardSection(const Module &M) {
return Triple(M.getTargetTriple()).isOSBinFormatMachO()
? "__DATA,__sancov_guards"
: "__sancov_guards";
}
static StringRef getSanCovTracePCGuardSectionStart(const Module &M) {
return Triple(M.getTargetTriple()).isOSBinFormatMachO()
? "\1section$start$__DATA$__sancov_guards"
: "__start___sancov_guards";
}
static StringRef getSanCovTracePCGuardSectionEnd(const Module &M) {
return Triple(M.getTargetTriple()).isOSBinFormatMachO()
? "\1section$end$__DATA$__sancov_guards"
: "__stop___sancov_guards";
}
namespace {
SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
@ -233,6 +215,9 @@ private:
SanCovWithCheckFunction->getNumUses() + SanCovTraceBB->getNumUses() +
SanCovTraceEnter->getNumUses();
}
StringRef getSanCovTracePCGuardSection() const;
StringRef getSanCovTracePCGuardSectionStart() const;
StringRef getSanCovTracePCGuardSectionEnd() const;
Function *SanCovFunction;
Function *SanCovWithCheckFunction;
Function *SanCovIndirCallFunction, *SanCovTracePCIndir;
@ -244,6 +229,7 @@ private:
InlineAsm *EmptyAsm;
Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy;
Module *CurModule;
Triple TargetTriple;
LLVMContext *C;
const DataLayout *DL;
@ -263,6 +249,7 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
C = &(M.getContext());
DL = &M.getDataLayout();
CurModule = &M;
TargetTriple = Triple(M.getTargetTriple());
HasSancovGuardsSection = false;
IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
IntptrPtrTy = PointerType::getUnqual(IntptrTy);
@ -382,11 +369,11 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
Function *CtorFunc;
GlobalVariable *SecStart = new GlobalVariable(
M, Int32PtrTy, false, GlobalVariable::ExternalLinkage, nullptr,
getSanCovTracePCGuardSectionStart(*CurModule));
getSanCovTracePCGuardSectionStart());
SecStart->setVisibility(GlobalValue::HiddenVisibility);
GlobalVariable *SecEnd = new GlobalVariable(
M, Int32PtrTy, false, GlobalVariable::ExternalLinkage, nullptr,
getSanCovTracePCGuardSectionEnd(*CurModule));
getSanCovTracePCGuardSectionEnd());
SecEnd->setVisibility(GlobalValue::HiddenVisibility);
std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
@ -534,7 +521,7 @@ void SanitizerCoverageModule::CreateFunctionGuardArray(size_t NumGuards,
Constant::getNullValue(ArrayOfInt32Ty), "__sancov_gen_");
if (auto Comdat = F.getComdat())
FunctionGuardArray->setComdat(Comdat);
FunctionGuardArray->setSection(getSanCovTracePCGuardSection(*CurModule));
FunctionGuardArray->setSection(getSanCovTracePCGuardSection());
}
bool SanitizerCoverageModule::InjectCoverage(Function &F,
@ -772,6 +759,27 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
}
}
StringRef SanitizerCoverageModule::getSanCovTracePCGuardSection() const {
if (TargetTriple.getObjectFormat() == Triple::COFF)
return ".SCOV$M";
if (TargetTriple.isOSBinFormatMachO())
return "__DATA,__sancov_guards";
return "__sancov_guards";
}
StringRef SanitizerCoverageModule::getSanCovTracePCGuardSectionStart() const {
if (TargetTriple.isOSBinFormatMachO())
return "\1section$start$__DATA$__sancov_guards";
return "__start___sancov_guards";
}
StringRef SanitizerCoverageModule::getSanCovTracePCGuardSectionEnd() const {
if (TargetTriple.isOSBinFormatMachO())
return "\1section$end$__DATA$__sancov_guards";
return "__stop___sancov_guards";
}
char SanitizerCoverageModule::ID = 0;
INITIALIZE_PASS_BEGIN(SanitizerCoverageModule, "sancov",
"SanitizerCoverage: TODO."