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[sanitizer-coverage] add a feature sanitizer-coverage-create-pc-table…
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…=1 (works with trace-pc-guard and inline-8bit-counters) that adds a static table of instrumented PCs to be used at run-time

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309335 91177308-0d34-0410-b5e6-96231b3b80d8
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@kcc
kcc committed Jul 27, 2017
1 parent e9ffbe5 commit 19b3038
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Showing 2 changed files with 104 additions and 22 deletions.
103 changes: 81 additions & 22 deletions lib/Transforms/Instrumentation/SanitizerCoverage.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,11 +57,13 @@ static const char *const SanCovTracePCGuardName =
"__sanitizer_cov_trace_pc_guard";
static const char *const SanCovTracePCGuardInitName =
"__sanitizer_cov_trace_pc_guard_init";
static const char *const SanCov8bitCountersInitName =
static const char *const SanCov8bitCountersInitName =
"__sanitizer_cov_8bit_counters_init";
static const char *const SanCovPCsInitName = "__sanitizer_cov_pcs_init";

static const char *const SanCovGuardsSectionName = "sancov_guards";
static const char *const SanCovCountersSectionName = "sancov_cntrs";
static const char *const SanCovPCsSectionName = "sancov_pcs";

static cl::opt<int> ClCoverageLevel(
"sanitizer-coverage-level",
Expand All @@ -77,9 +79,19 @@ static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
cl::desc("pc tracing with a guard"),
cl::Hidden, cl::init(false));

static cl::opt<bool> ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
cl::desc("increments 8-bit counter for every edge"),
cl::Hidden, cl::init(false));
// If true, we create a global variable that contains PCs of all instrumented
// BBs, put this global into a named section, and pass this section's bounds
// to __sanitizer_cov_pcs_init.
// This way the coverage instrumentation does not need to acquire the PCs
// at run-time. Works with trace-pc-guard and inline-8bit-counters.
static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-create-pc-table",
cl::desc("create a static PC table"),
cl::Hidden, cl::init(false));

static cl::opt<bool>
ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
cl::desc("increments 8-bit counter for every edge"),
cl::Hidden, cl::init(false));

static cl::opt<bool>
ClCMPTracing("sanitizer-coverage-trace-compares",
Expand Down Expand Up @@ -172,10 +184,13 @@ class SanitizerCoverageModule : public ModulePass {
GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
Function &F, Type *Ty,
const char *Section);
void CreateFunctionLocalArrays(size_t NumGuards, Function &F);
void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
void CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx);
void CreateInitCallForSection(Module &M, const char *InitFunctionName,
Type *Ty, const std::string &Section);
Function *CreateInitCallsForSections(Module &M, const char *InitFunctionName,
Type *Ty, const char *Section);
std::pair<GlobalVariable *, GlobalVariable *>
CreateSecStartEnd(Module &M, const char *Section, Type *Ty);

void SetNoSanitizeMetadata(Instruction *I) {
I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
Expand All @@ -201,17 +216,16 @@ class SanitizerCoverageModule : public ModulePass {

GlobalVariable *FunctionGuardArray; // for trace-pc-guard.
GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters.
GlobalVariable *FunctionPCsArray; // for create-pc-table.

SanitizerCoverageOptions Options;
};

} // namespace

void SanitizerCoverageModule::CreateInitCallForSection(
Module &M, const char *InitFunctionName, Type *Ty,
const std::string &Section) {
IRBuilder<> IRB(M.getContext());
Function *CtorFunc;
std::pair<GlobalVariable *, GlobalVariable *>
SanitizerCoverageModule::CreateSecStartEnd(Module &M, const char *Section,
Type *Ty) {
GlobalVariable *SecStart =
new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr,
getSectionStart(Section));
Expand All @@ -221,6 +235,18 @@ void SanitizerCoverageModule::CreateInitCallForSection(
nullptr, getSectionEnd(Section));
SecEnd->setVisibility(GlobalValue::HiddenVisibility);

return std::make_pair(SecStart, SecEnd);
}


Function *SanitizerCoverageModule::CreateInitCallsForSections(
Module &M, const char *InitFunctionName, Type *Ty,
const char *Section) {
IRBuilder<> IRB(M.getContext());
auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
auto SecStart = SecStartEnd.first;
auto SecEnd = SecStartEnd.second;
Function *CtorFunc;
std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
M, SanCovModuleCtorName, InitFunctionName, {Ty, Ty},
{IRB.CreatePointerCast(SecStart, Ty), IRB.CreatePointerCast(SecEnd, Ty)});
Expand All @@ -232,6 +258,7 @@ void SanitizerCoverageModule::CreateInitCallForSection(
} else {
appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
}
return CtorFunc;
}

bool SanitizerCoverageModule::runOnModule(Module &M) {
Expand All @@ -243,6 +270,7 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
TargetTriple = Triple(M.getTargetTriple());
FunctionGuardArray = nullptr;
Function8bitCounterArray = nullptr;
FunctionPCsArray = nullptr;
IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
IntptrPtrTy = PointerType::getUnqual(IntptrTy);
Type *VoidTy = Type::getVoidTy(*C);
Expand Down Expand Up @@ -305,13 +333,23 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
for (auto &F : M)
runOnFunction(F);

Function *Ctor = nullptr;

if (FunctionGuardArray)
CreateInitCallForSection(M, SanCovTracePCGuardInitName, Int32PtrTy,
SanCovGuardsSectionName);
Ctor = CreateInitCallsForSections(M, SanCovTracePCGuardInitName, Int32PtrTy,
SanCovGuardsSectionName);
if (Function8bitCounterArray)
CreateInitCallForSection(M, SanCov8bitCountersInitName, Int8PtrTy,
SanCovCountersSectionName);

Ctor = CreateInitCallsForSections(M, SanCov8bitCountersInitName, Int8PtrTy,
SanCovCountersSectionName);
if (Ctor && ClCreatePCTable) {
auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, Int8PtrTy);
Function *InitFunction = declareSanitizerInitFunction(
M, SanCovPCsInitName, {Int8PtrTy, Int8PtrTy});
IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
IRBCtor.CreateCall(InitFunction,
{IRB.CreatePointerCast(SecStartEnd.first, Int8PtrTy),
IRB.CreatePointerCast(SecStartEnd.second, Int8PtrTy)});
}
return true;
}

Expand Down Expand Up @@ -450,20 +488,41 @@ GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection(
Array->setSection(getSectionName(Section));
return Array;
}
void SanitizerCoverageModule::CreateFunctionLocalArrays(size_t NumGuards,
Function &F) {

void SanitizerCoverageModule::CreatePCArray(Function &F,
ArrayRef<BasicBlock *> AllBlocks) {
size_t N = AllBlocks.size();
assert(N);
assert(&F.getEntryBlock() == AllBlocks[0]);
SmallVector<Constant *, 16> PCs;
IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
PCs.push_back((Constant *)IRB.CreatePointerCast(&F, Int8PtrTy));
for (size_t i = 1; i < N; i++)
PCs.push_back(BlockAddress::get(AllBlocks[i]));
FunctionPCsArray =
CreateFunctionLocalArrayInSection(N, F, Int8PtrTy, SanCovPCsSectionName);
FunctionPCsArray->setInitializer(
ConstantArray::get(ArrayType::get(Int8PtrTy, N), PCs));
FunctionPCsArray->setConstant(true);
FunctionPCsArray->setAlignment(DL->getPointerSize());
}

void SanitizerCoverageModule::CreateFunctionLocalArrays(
Function &F, ArrayRef<BasicBlock *> AllBlocks) {
if (Options.TracePCGuard)
FunctionGuardArray = CreateFunctionLocalArrayInSection(
NumGuards, F, Int32Ty, SanCovGuardsSectionName);
AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
if (Options.Inline8bitCounters)
Function8bitCounterArray = CreateFunctionLocalArrayInSection(
NumGuards, F, Int8Ty, SanCovCountersSectionName);
AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
if (ClCreatePCTable)
CreatePCArray(F, AllBlocks);
}

bool SanitizerCoverageModule::InjectCoverage(Function &F,
ArrayRef<BasicBlock *> AllBlocks) {
if (AllBlocks.empty()) return false;
CreateFunctionLocalArrays(AllBlocks.size(), F);
CreateFunctionLocalArrays(F, AllBlocks);
for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
InjectCoverageAtBlock(F, *AllBlocks[i], i);
return true;
Expand Down
23 changes: 23 additions & 0 deletions test/Instrumentation/SanitizerCoverage/pc-table.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,23 @@
; Test -sanitizer-coverage-create-pc-table=1
; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-trace-pc-guard -sanitizer-coverage-create-pc-table=1 -S | FileCheck %s
; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-inline-8bit-counters -sanitizer-coverage-create-pc-table=1 -S | FileCheck %s

target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-unknown-linux-gnu"
define void @foo(i32* %a) sanitize_address {
entry:
%tobool = icmp eq i32* %a, null
br i1 %tobool, label %if.end, label %if.then

if.then: ; preds = %entry
store i32 0, i32* %a, align 4
br label %if.end

if.end: ; preds = %entry, %if.then
ret void
}

; CHECK: private constant [3 x i8*] [{{.*}}@foo{{.*}}blockaddress{{.*}}blockaddress{{.*}}], section "__sancov_pcs", align 8
; CHECK: define internal void @sancov.module_ctor
; CHECK: call void @__sanitizer_cov
; CHECK: call void @__sanitizer_cov_pcs_init

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