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llvm-project/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp

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//===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Coverage instrumentation done on LLVM IR level, works with Sanitizers.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
#define DEBUG_TYPE "sancov"
static const char *const SanCovTracePCIndirName =
"__sanitizer_cov_trace_pc_indir";
static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc";
static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1";
static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2";
static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4";
static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8";
static const char *const SanCovTraceConstCmp1 =
"__sanitizer_cov_trace_const_cmp1";
static const char *const SanCovTraceConstCmp2 =
"__sanitizer_cov_trace_const_cmp2";
static const char *const SanCovTraceConstCmp4 =
"__sanitizer_cov_trace_const_cmp4";
static const char *const SanCovTraceConstCmp8 =
"__sanitizer_cov_trace_const_cmp8";
static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4";
static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8";
static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep";
static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch";
static const char *const SanCovModuleCtorName = "sancov.module_ctor";
static const uint64_t SanCtorAndDtorPriority = 2;
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 =
"__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 const char *const SanCovLowestStackName = "__sancov_lowest_stack";
static cl::opt<int> ClCoverageLevel(
"sanitizer-coverage-level",
cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
"3: all blocks and critical edges"),
cl::Hidden, cl::init(0));
static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
cl::desc("Experimental pc tracing"), cl::Hidden,
cl::init(false));
static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
cl::desc("pc tracing with a guard"),
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-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",
cl::desc("Tracing of CMP and similar instructions"),
cl::Hidden, cl::init(false));
static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
cl::desc("Tracing of DIV instructions"),
cl::Hidden, cl::init(false));
static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
cl::desc("Tracing of GEP instructions"),
cl::Hidden, cl::init(false));
static cl::opt<bool>
ClPruneBlocks("sanitizer-coverage-prune-blocks",
cl::desc("Reduce the number of instrumented blocks"),
cl::Hidden, cl::init(true));
static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
cl::desc("max stack depth tracing"),
cl::Hidden, cl::init(false));
namespace {
SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
SanitizerCoverageOptions Res;
switch (LegacyCoverageLevel) {
case 0:
Res.CoverageType = SanitizerCoverageOptions::SCK_None;
break;
case 1:
Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
break;
case 2:
Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
break;
case 3:
Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
break;
case 4:
Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
Res.IndirectCalls = true;
break;
}
return Res;
}
SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
// Sets CoverageType and IndirectCalls.
SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
Options.IndirectCalls |= CLOpts.IndirectCalls;
Options.TraceCmp |= ClCMPTracing;
Options.TraceDiv |= ClDIVTracing;
Options.TraceGep |= ClGEPTracing;
Options.TracePC |= ClTracePC;
Options.TracePCGuard |= ClTracePCGuard;
Options.Inline8bitCounters |= ClInline8bitCounters;
Options.PCTable |= ClCreatePCTable;
Options.NoPrune |= !ClPruneBlocks;
Options.StackDepth |= ClStackDepth;
if (!Options.TracePCGuard && !Options.TracePC &&
!Options.Inline8bitCounters && !Options.StackDepth)
Options.TracePCGuard = true; // TracePCGuard is default.
return Options;
}
class SanitizerCoverageModule : public ModulePass {
public:
SanitizerCoverageModule(
const SanitizerCoverageOptions &Options = SanitizerCoverageOptions())
: ModulePass(ID), Options(OverrideFromCL(Options)) {
initializeSanitizerCoverageModulePass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module &M) override;
bool runOnFunction(Function &F);
static char ID; // Pass identification, replacement for typeid
StringRef getPassName() const override { return "SanitizerCoverageModule"; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<PostDominatorTreeWrapperPass>();
}
private:
void InjectCoverageForIndirectCalls(Function &F,
ArrayRef<Instruction *> IndirCalls);
void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
void InjectTraceForDiv(Function &F,
ArrayRef<BinaryOperator *> DivTraceTargets);
void InjectTraceForGep(Function &F,
ArrayRef<GetElementPtrInst *> GepTraceTargets);
void InjectTraceForSwitch(Function &F,
ArrayRef<Instruction *> SwitchTraceTargets);
bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
bool IsLeafFunc = true);
GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
Function &F, Type *Ty,
const char *Section);
GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
bool IsLeafFunc = true);
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"),
MDNode::get(*C, None));
}
std::string getSectionName(const std::string &Section) const;
std::string getSectionStart(const std::string &Section) const;
std::string getSectionEnd(const std::string &Section) const;
Function *SanCovTracePCIndir;
Function *SanCovTracePC, *SanCovTracePCGuard;
Function *SanCovTraceCmpFunction[4];
Function *SanCovTraceConstCmpFunction[4];
Function *SanCovTraceDivFunction[2];
Function *SanCovTraceGepFunction;
Function *SanCovTraceSwitchFunction;
GlobalVariable *SanCovLowestStack;
InlineAsm *EmptyAsm;
Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy,
*Int16Ty, *Int8Ty, *Int8PtrTy;
Module *CurModule;
Triple TargetTriple;
LLVMContext *C;
const DataLayout *DL;
GlobalVariable *FunctionGuardArray; // for trace-pc-guard.
GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters.
GlobalVariable *FunctionPCsArray; // for pc-table.
SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
SanitizerCoverageOptions Options;
};
} // namespace
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));
SecStart->setVisibility(GlobalValue::HiddenVisibility);
GlobalVariable *SecEnd =
new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage,
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)});
if (TargetTriple.supportsCOMDAT()) {
// Use comdat to dedup CtorFunc.
CtorFunc->setComdat(M.getOrInsertComdat(SanCovModuleCtorName));
appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
} else {
appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
}
return CtorFunc;
}
bool SanitizerCoverageModule::runOnModule(Module &M) {
if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
return false;
C = &(M.getContext());
DL = &M.getDataLayout();
CurModule = &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);
IRBuilder<> IRB(*C);
Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
Int64Ty = IRB.getInt64Ty();
Int32Ty = IRB.getInt32Ty();
Int16Ty = IRB.getInt16Ty();
Int8Ty = IRB.getInt8Ty();
SanCovTracePCIndir = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy));
SanCovTraceCmpFunction[0] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceCmp1, VoidTy, IRB.getInt8Ty(), IRB.getInt8Ty()));
SanCovTraceCmpFunction[1] = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTraceCmp2, VoidTy, IRB.getInt16Ty(),
IRB.getInt16Ty()));
SanCovTraceCmpFunction[2] = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTraceCmp4, VoidTy, IRB.getInt32Ty(),
IRB.getInt32Ty()));
SanCovTraceCmpFunction[3] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty));
SanCovTraceConstCmpFunction[0] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp1, VoidTy, Int8Ty, Int8Ty));
SanCovTraceConstCmpFunction[1] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp2, VoidTy, Int16Ty, Int16Ty));
SanCovTraceConstCmpFunction[2] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp4, VoidTy, Int32Ty, Int32Ty));
SanCovTraceConstCmpFunction[3] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty));
SanCovTraceDivFunction[0] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceDiv4, VoidTy, IRB.getInt32Ty()));
SanCovTraceDivFunction[1] =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceDiv8, VoidTy, Int64Ty));
SanCovTraceGepFunction =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceGep, VoidTy, IntptrTy));
SanCovTraceSwitchFunction =
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy));
Constant *SanCovLowestStackConstant =
M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy);
SanCovLowestStack = cast<GlobalVariable>(SanCovLowestStackConstant);
SanCovLowestStack->setThreadLocalMode(
GlobalValue::ThreadLocalMode::InitialExecTLSModel);
if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy));
// Make sure smaller parameters are zero-extended to i64 as required by the
// x86_64 ABI.
if (TargetTriple.getArch() == Triple::x86_64) {
for (int i = 0; i < 3; i++) {
SanCovTraceCmpFunction[i]->addParamAttr(0, Attribute::ZExt);
SanCovTraceCmpFunction[i]->addParamAttr(1, Attribute::ZExt);
SanCovTraceConstCmpFunction[i]->addParamAttr(0, Attribute::ZExt);
SanCovTraceConstCmpFunction[i]->addParamAttr(1, Attribute::ZExt);
}
SanCovTraceDivFunction[0]->addParamAttr(0, Attribute::ZExt);
}
// 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);
SanCovTracePC = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTracePCName, VoidTy));
SanCovTracePCGuard = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
SanCovTracePCGuardName, VoidTy, Int32PtrTy));
for (auto &F : M)
runOnFunction(F);
Function *Ctor = nullptr;
if (FunctionGuardArray)
Ctor = CreateInitCallsForSections(M, SanCovTracePCGuardInitName, Int32PtrTy,
SanCovGuardsSectionName);
if (Function8bitCounterArray)
Ctor = CreateInitCallsForSections(M, SanCov8bitCountersInitName, Int8PtrTy,
SanCovCountersSectionName);
if (Ctor && Options.PCTable) {
auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrPtrTy);
Function *InitFunction = declareSanitizerInitFunction(
M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
IRBCtor.CreateCall(InitFunction,
{IRB.CreatePointerCast(SecStartEnd.first, IntptrPtrTy),
IRB.CreatePointerCast(SecStartEnd.second, IntptrPtrTy)});
}
// We don't reference these arrays directly in any of our runtime functions,
// so we need to prevent them from being dead stripped.
if (TargetTriple.isOSBinFormatMachO())
appendToUsed(M, GlobalsToAppendToUsed);
return true;
}
// True if block has successors and it dominates all of them.
static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
if (succ_begin(BB) == succ_end(BB))
return false;
for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) {
if (!DT->dominates(BB, SUCC))
return false;
}
return true;
}
// True if block has predecessors and it postdominates all of them.
static bool isFullPostDominator(const BasicBlock *BB,
const PostDominatorTree *PDT) {
if (pred_begin(BB) == pred_end(BB))
return false;
for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) {
if (!PDT->dominates(BB, PRED))
return false;
}
return true;
}
static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
const DominatorTree *DT,
const PostDominatorTree *PDT,
const SanitizerCoverageOptions &Options) {
// Don't insert coverage for unreachable blocks: we will never call
// __sanitizer_cov() for them, so counting them in
// NumberOfInstrumentedBlocks() might complicate calculation of code coverage
// percentage. Also, unreachable instructions frequently have no debug
// locations.
if (isa<UnreachableInst>(BB->getTerminator()))
return false;
// Don't insert coverage into blocks without a valid insertion point
// (catchswitch blocks).
if (BB->getFirstInsertionPt() == BB->end())
return false;
if (Options.NoPrune || &F.getEntryBlock() == BB)
return true;
if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
&F.getEntryBlock() != BB)
return false;
// Do not instrument full dominators, or full post-dominators with multiple
// predecessors.
return !isFullDominator(BB, DT)
&& !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
}
bool SanitizerCoverageModule::runOnFunction(Function &F) {
if (F.empty())
return false;
if (F.getName().find(".module_ctor") != std::string::npos)
return false; // Should not instrument sanitizer init functions.
if (F.getName().startswith("__sanitizer_"))
return false; // Don't instrument __sanitizer_* callbacks.
// Don't touch available_externally functions, their actual body is elewhere.
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
return false;
// Don't instrument MSVC CRT configuration helpers. They may run before normal
// initialization.
if (F.getName() == "__local_stdio_printf_options" ||
F.getName() == "__local_stdio_scanf_options")
return false;
// Don't instrument functions using SEH for now. Splitting basic blocks like
// we do for coverage breaks WinEHPrepare.
// FIXME: Remove this when SEH no longer uses landingpad pattern matching.
if (F.hasPersonalityFn() &&
isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
return false;
if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
SplitAllCriticalEdges(F);
SmallVector<Instruction *, 8> IndirCalls;
SmallVector<BasicBlock *, 16> BlocksToInstrument;
SmallVector<Instruction *, 8> CmpTraceTargets;
SmallVector<Instruction *, 8> SwitchTraceTargets;
SmallVector<BinaryOperator *, 8> DivTraceTargets;
SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
const DominatorTree *DT =
&getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
const PostDominatorTree *PDT =
&getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree();
bool IsLeafFunc = true;
for (auto &BB : F) {
if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
BlocksToInstrument.push_back(&BB);
for (auto &Inst : BB) {
if (Options.IndirectCalls) {
CallSite CS(&Inst);
if (CS && !CS.getCalledFunction())
IndirCalls.push_back(&Inst);
}
if (Options.TraceCmp) {
if (isa<ICmpInst>(&Inst))
CmpTraceTargets.push_back(&Inst);
if (isa<SwitchInst>(&Inst))
SwitchTraceTargets.push_back(&Inst);
}
if (Options.TraceDiv)
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
if (BO->getOpcode() == Instruction::SDiv ||
BO->getOpcode() == Instruction::UDiv)
DivTraceTargets.push_back(BO);
if (Options.TraceGep)
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
GepTraceTargets.push_back(GEP);
if (Options.StackDepth)
if (isa<InvokeInst>(Inst) ||
(isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst)))
IsLeafFunc = false;
}
}
InjectCoverage(F, BlocksToInstrument, IsLeafFunc);
InjectCoverageForIndirectCalls(F, IndirCalls);
InjectTraceForCmp(F, CmpTraceTargets);
InjectTraceForSwitch(F, SwitchTraceTargets);
InjectTraceForDiv(F, DivTraceTargets);
InjectTraceForGep(F, GepTraceTargets);
return true;
}
GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection(
size_t NumElements, Function &F, Type *Ty, const char *Section) {
ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
auto Array = new GlobalVariable(
*CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
Constant::getNullValue(ArrayTy), "__sancov_gen_");
if (auto Comdat = F.getComdat())
Array->setComdat(Comdat);
Array->setSection(getSectionName(Section));
Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize()
: Ty->getPrimitiveSizeInBits() / 8);
return Array;
}
GlobalVariable *
SanitizerCoverageModule::CreatePCArray(Function &F,
ArrayRef<BasicBlock *> AllBlocks) {
size_t N = AllBlocks.size();
assert(N);
SmallVector<Constant *, 32> PCs;
IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
for (size_t i = 0; i < N; i++) {
if (&F.getEntryBlock() == AllBlocks[i]) {
PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy));
PCs.push_back((Constant *)IRB.CreateIntToPtr(
ConstantInt::get(IntptrTy, 1), IntptrPtrTy));
} else {
PCs.push_back((Constant *)IRB.CreatePointerCast(
BlockAddress::get(AllBlocks[i]), IntptrPtrTy));
PCs.push_back((Constant *)IRB.CreateIntToPtr(
ConstantInt::get(IntptrTy, 0), IntptrPtrTy));
}
}
auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy,
SanCovPCsSectionName);
PCArray->setInitializer(
ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs));
PCArray->setConstant(true);
return PCArray;
}
void SanitizerCoverageModule::CreateFunctionLocalArrays(
Function &F, ArrayRef<BasicBlock *> AllBlocks) {
if (Options.TracePCGuard) {
FunctionGuardArray = CreateFunctionLocalArrayInSection(
AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
GlobalsToAppendToUsed.push_back(FunctionGuardArray);
}
if (Options.Inline8bitCounters) {
Function8bitCounterArray = CreateFunctionLocalArrayInSection(
AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
GlobalsToAppendToUsed.push_back(Function8bitCounterArray);
}
if (Options.PCTable) {
FunctionPCsArray = CreatePCArray(F, AllBlocks);
GlobalsToAppendToUsed.push_back(FunctionPCsArray);
}
}
bool SanitizerCoverageModule::InjectCoverage(Function &F,
ArrayRef<BasicBlock *> AllBlocks,
bool IsLeafFunc) {
if (AllBlocks.empty()) return false;
CreateFunctionLocalArrays(F, AllBlocks);
for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc);
return true;
}
// On every indirect call we call a run-time function
// __sanitizer_cov_indir_call* with two parameters:
// - callee address,
// - global cache array that contains CacheSize pointers (zero-initialized).
// The cache is used to speed up recording the caller-callee pairs.
// The address of the caller is passed implicitly via caller PC.
// CacheSize is encoded in the name of the run-time function.
void SanitizerCoverageModule::InjectCoverageForIndirectCalls(
Function &F, ArrayRef<Instruction *> IndirCalls) {
if (IndirCalls.empty())
return;
assert(Options.TracePC || Options.TracePCGuard || Options.Inline8bitCounters);
for (auto I : IndirCalls) {
IRBuilder<> IRB(I);
CallSite CS(I);
Value *Callee = CS.getCalledValue();
if (isa<InlineAsm>(Callee))
continue;
IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy));
}
}
// For every switch statement we insert a call:
// __sanitizer_cov_trace_switch(CondValue,
// {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
void SanitizerCoverageModule::InjectTraceForSwitch(
Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
for (auto I : SwitchTraceTargets) {
if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
IRBuilder<> IRB(I);
SmallVector<Constant *, 16> Initializers;
Value *Cond = SI->getCondition();
if (Cond->getType()->getScalarSizeInBits() >
Int64Ty->getScalarSizeInBits())
continue;
Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
Initializers.push_back(
ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
if (Cond->getType()->getScalarSizeInBits() <
Int64Ty->getScalarSizeInBits())
Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
for (auto It : SI->cases()) {
Constant *C = It.getCaseValue();
if (C->getType()->getScalarSizeInBits() <
Int64Ty->getScalarSizeInBits())
C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
Initializers.push_back(C);
}
std::sort(Initializers.begin() + 2, Initializers.end(),
[](const Constant *A, const Constant *B) {
return cast<ConstantInt>(A)->getLimitedValue() <
cast<ConstantInt>(B)->getLimitedValue();
});
ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
GlobalVariable *GV = new GlobalVariable(
*CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
ConstantArray::get(ArrayOfInt64Ty, Initializers),
"__sancov_gen_cov_switch_values");
IRB.CreateCall(SanCovTraceSwitchFunction,
{Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
}
}
}
void SanitizerCoverageModule::InjectTraceForDiv(
Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
for (auto BO : DivTraceTargets) {
IRBuilder<> IRB(BO);
Value *A1 = BO->getOperand(1);
if (isa<ConstantInt>(A1)) continue;
if (!A1->getType()->isIntegerTy())
continue;
uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
int CallbackIdx = TypeSize == 32 ? 0 :
TypeSize == 64 ? 1 : -1;
if (CallbackIdx < 0) continue;
auto Ty = Type::getIntNTy(*C, TypeSize);
IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
{IRB.CreateIntCast(A1, Ty, true)});
}
}
void SanitizerCoverageModule::InjectTraceForGep(
Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
for (auto GEP : GepTraceTargets) {
IRBuilder<> IRB(GEP);
for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I)
if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy())
IRB.CreateCall(SanCovTraceGepFunction,
{IRB.CreateIntCast(*I, IntptrTy, true)});
}
}
void SanitizerCoverageModule::InjectTraceForCmp(
Function &, ArrayRef<Instruction *> CmpTraceTargets) {
for (auto I : CmpTraceTargets) {
if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
IRBuilder<> IRB(ICMP);
Value *A0 = ICMP->getOperand(0);
Value *A1 = ICMP->getOperand(1);
if (!A0->getType()->isIntegerTy())
continue;
uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
int CallbackIdx = TypeSize == 8 ? 0 :
TypeSize == 16 ? 1 :
TypeSize == 32 ? 2 :
TypeSize == 64 ? 3 : -1;
if (CallbackIdx < 0) continue;
// __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
bool FirstIsConst = isa<ConstantInt>(A0);
bool SecondIsConst = isa<ConstantInt>(A1);
// If both are const, then we don't need such a comparison.
if (FirstIsConst && SecondIsConst) continue;
// If only one is const, then make it the first callback argument.
if (FirstIsConst || SecondIsConst) {
CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
if (SecondIsConst)
std::swap(A0, A1);
}
auto Ty = Type::getIntNTy(*C, TypeSize);
IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
IRB.CreateIntCast(A1, Ty, true)});
}
}
}
void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
size_t Idx,
bool IsLeafFunc) {
BasicBlock::iterator IP = BB.getFirstInsertionPt();
bool IsEntryBB = &BB == &F.getEntryBlock();
DebugLoc EntryLoc;
if (IsEntryBB) {
if (auto SP = F.getSubprogram())
EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
// Keep static allocas and llvm.localescape calls in the entry block. Even
// if we aren't splitting the block, it's nice for allocas to be before
// calls.
IP = PrepareToSplitEntryBlock(BB, IP);
} else {
EntryLoc = IP->getDebugLoc();
}
IRBuilder<> IRB(&*IP);
IRB.SetCurrentDebugLocation(EntryLoc);
if (Options.TracePC) {
IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC.
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
}
if (Options.TracePCGuard) {
auto GuardPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy),
ConstantInt::get(IntptrTy, Idx * 4)),
Int32PtrTy);
IRB.CreateCall(SanCovTracePCGuard, GuardPtr);
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
}
if (Options.Inline8bitCounters) {
auto CounterPtr = IRB.CreateGEP(
Function8bitCounterArray,
{ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
auto Load = IRB.CreateLoad(CounterPtr);
auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1));
auto Store = IRB.CreateStore(Inc, CounterPtr);
SetNoSanitizeMetadata(Load);
SetNoSanitizeMetadata(Store);
}
if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
// Check stack depth. If it's the deepest so far, record it.
Function *GetFrameAddr =
Intrinsic::getDeclaration(F.getParent(), Intrinsic::frameaddress);
auto FrameAddrPtr =
IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)});
auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy);
auto LowestStack = IRB.CreateLoad(SanCovLowestStack);
auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack);
auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false);
IRBuilder<> ThenIRB(ThenTerm);
auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack);
SetNoSanitizeMetadata(LowestStack);
SetNoSanitizeMetadata(Store);
}
}
std::string
SanitizerCoverageModule::getSectionName(const std::string &Section) const {
if (TargetTriple.getObjectFormat() == Triple::COFF)
return ".SCOV$M";
if (TargetTriple.isOSBinFormatMachO())
return "__DATA,__" + Section;
return "__" + Section;
}
std::string
SanitizerCoverageModule::getSectionStart(const std::string &Section) const {
if (TargetTriple.isOSBinFormatMachO())
return "\1section$start$__DATA$__" + Section;
return "__start___" + Section;
}
std::string
SanitizerCoverageModule::getSectionEnd(const std::string &Section) const {
if (TargetTriple.isOSBinFormatMachO())
return "\1section$end$__DATA$__" + Section;
return "__stop___" + Section;
}
char SanitizerCoverageModule::ID = 0;
INITIALIZE_PASS_BEGIN(SanitizerCoverageModule, "sancov",
"SanitizerCoverage: TODO."
"ModulePass",
false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
INITIALIZE_PASS_END(SanitizerCoverageModule, "sancov",
"SanitizerCoverage: TODO."
"ModulePass",
false, false)
ModulePass *llvm::createSanitizerCoverageModulePass(
const SanitizerCoverageOptions &Options) {
return new SanitizerCoverageModule(Options);
}
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