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llvm-project/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
Fangrui Song 5809a32e7c [gcov] Add __gcov_dump/__gcov_reset and delete __gcov_flush 
GCC r187297 (2012-05) introduced `__gcov_dump` and `__gcov_reset`.
  `__gcov_flush = __gcov_dump + __gcov_reset`

The resolution to https://gcc.gnu.org/PR93623 ("No need to dump gcdas when forking" target GCC 11.0) removed the unuseful and undocumented __gcov_flush.

Close PR38064.

Reviewed By: calixte, serge-sans-paille

Differential Revision: https://reviews.llvm.org/D83149
2020-07-18 15:07:46 -07:00

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//===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This pass implements GCOV-style profiling. When this pass is run it emits
// "gcno" files next to the existing source, and instruments the code that runs
// to records the edges between blocks that run and emit a complementary "gcda"
// file on exit.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Regex.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
#include <memory>
#include <string>
#include <utility>
using namespace llvm;
namespace endian = llvm::support::endian;
#define DEBUG_TYPE "insert-gcov-profiling"
enum : uint32_t {
GCOV_TAG_FUNCTION = 0x01000000,
GCOV_TAG_BLOCKS = 0x01410000,
GCOV_TAG_ARCS = 0x01430000,
GCOV_TAG_LINES = 0x01450000,
};
static cl::opt<std::string> DefaultGCOVVersion("default-gcov-version",
cl::init("408*"), cl::Hidden,
cl::ValueRequired);
// Returns the number of words which will be used to represent this string.
static unsigned wordsOfString(StringRef s) {
// Length + NUL-terminated string + 0~3 padding NULs.
return (s.size() / 4) + 2;
}
GCOVOptions GCOVOptions::getDefault() {
GCOVOptions Options;
Options.EmitNotes = true;
Options.EmitData = true;
Options.NoRedZone = false;
if (DefaultGCOVVersion.size() != 4) {
llvm::report_fatal_error(std::string("Invalid -default-gcov-version: ") +
DefaultGCOVVersion);
}
memcpy(Options.Version, DefaultGCOVVersion.c_str(), 4);
return Options;
}
namespace {
class GCOVFunction;
class GCOVProfiler {
public:
GCOVProfiler() : GCOVProfiler(GCOVOptions::getDefault()) {}
GCOVProfiler(const GCOVOptions &Opts) : Options(Opts) {}
bool
runOnModule(Module &M,
std::function<const TargetLibraryInfo &(Function &F)> GetTLI);
void write(uint32_t i) {
char Bytes[4];
endian::write32(Bytes, i, Endian);
os->write(Bytes, 4);
}
void writeString(StringRef s) {
write(wordsOfString(s) - 1);
os->write(s.data(), s.size());
os->write_zeros(4 - s.size() % 4);
}
void writeBytes(const char *Bytes, int Size) { os->write(Bytes, Size); }
private:
// Create the .gcno files for the Module based on DebugInfo.
void emitProfileNotes();
// Modify the program to track transitions along edges and call into the
// profiling runtime to emit .gcda files when run.
bool emitProfileArcs();
bool isFunctionInstrumented(const Function &F);
std::vector<Regex> createRegexesFromString(StringRef RegexesStr);
static bool doesFilenameMatchARegex(StringRef Filename,
std::vector<Regex> &Regexes);
// Get pointers to the functions in the runtime library.
FunctionCallee getStartFileFunc(const TargetLibraryInfo *TLI);
FunctionCallee getEmitFunctionFunc(const TargetLibraryInfo *TLI);
FunctionCallee getEmitArcsFunc(const TargetLibraryInfo *TLI);
FunctionCallee getSummaryInfoFunc();
FunctionCallee getEndFileFunc();
// Add the function to write out all our counters to the global destructor
// list.
Function *
insertCounterWriteout(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
Function *insertReset(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
bool AddFlushBeforeForkAndExec();
enum class GCovFileType { GCNO, GCDA };
std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
GCOVOptions Options;
support::endianness Endian;
raw_ostream *os;
// Checksum, produced by hash of EdgeDestinations
SmallVector<uint32_t, 4> FileChecksums;
Module *M = nullptr;
std::function<const TargetLibraryInfo &(Function &F)> GetTLI;
LLVMContext *Ctx = nullptr;
SmallVector<std::unique_ptr<GCOVFunction>, 16> Funcs;
std::vector<Regex> FilterRe;
std::vector<Regex> ExcludeRe;
StringMap<bool> InstrumentedFiles;
};
class GCOVProfilerLegacyPass : public ModulePass {
public:
static char ID;
GCOVProfilerLegacyPass()
: GCOVProfilerLegacyPass(GCOVOptions::getDefault()) {}
GCOVProfilerLegacyPass(const GCOVOptions &Opts)
: ModulePass(ID), Profiler(Opts) {
initializeGCOVProfilerLegacyPassPass(*PassRegistry::getPassRegistry());
}
StringRef getPassName() const override { return "GCOV Profiler"; }
bool runOnModule(Module &M) override {
return Profiler.runOnModule(M, [this](Function &F) -> TargetLibraryInfo & {
return getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
});
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<TargetLibraryInfoWrapperPass>();
}
private:
GCOVProfiler Profiler;
};
}
char GCOVProfilerLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(
GCOVProfilerLegacyPass, "insert-gcov-profiling",
"Insert instrumentation for GCOV profiling", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(
GCOVProfilerLegacyPass, "insert-gcov-profiling",
"Insert instrumentation for GCOV profiling", false, false)
ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
return new GCOVProfilerLegacyPass(Options);
}
static StringRef getFunctionName(const DISubprogram *SP) {
if (!SP->getLinkageName().empty())
return SP->getLinkageName();
return SP->getName();
}
/// Extract a filename for a DISubprogram.
///
/// Prefer relative paths in the coverage notes. Clang also may split
/// up absolute paths into a directory and filename component. When
/// the relative path doesn't exist, reconstruct the absolute path.
static SmallString<128> getFilename(const DISubprogram *SP) {
SmallString<128> Path;
StringRef RelPath = SP->getFilename();
if (sys::fs::exists(RelPath))
Path = RelPath;
else
sys::path::append(Path, SP->getDirectory(), SP->getFilename());
return Path;
}
namespace {
class GCOVRecord {
protected:
GCOVProfiler *P;
GCOVRecord(GCOVProfiler *P) : P(P) {}
void write(uint32_t i) { P->write(i); }
void writeString(StringRef s) { P->writeString(s); }
void writeBytes(const char *Bytes, int Size) { P->writeBytes(Bytes, Size); }
};
class GCOVFunction;
class GCOVBlock;
// Constructed only by requesting it from a GCOVBlock, this object stores a
// list of line numbers and a single filename, representing lines that belong
// to the block.
class GCOVLines : public GCOVRecord {
public:
void addLine(uint32_t Line) {
assert(Line != 0 && "Line zero is not a valid real line number.");
Lines.push_back(Line);
}
uint32_t length() const {
return 1 + wordsOfString(Filename) + Lines.size();
}
void writeOut() {
write(0);
writeString(Filename);
for (int i = 0, e = Lines.size(); i != e; ++i)
write(Lines[i]);
}
GCOVLines(GCOVProfiler *P, StringRef F)
: GCOVRecord(P), Filename(std::string(F)) {}
private:
std::string Filename;
SmallVector<uint32_t, 32> Lines;
};
// Represent a basic block in GCOV. Each block has a unique number in the
// function, number of lines belonging to each block, and a set of edges to
// other blocks.
class GCOVBlock : public GCOVRecord {
public:
GCOVLines &getFile(StringRef Filename) {
return LinesByFile.try_emplace(Filename, P, Filename).first->second;
}
void addEdge(GCOVBlock &Successor) {
OutEdges.push_back(&Successor);
}
void writeOut() {
uint32_t Len = 3;
SmallVector<StringMapEntry<GCOVLines> *, 32> SortedLinesByFile;
for (auto &I : LinesByFile) {
Len += I.second.length();
SortedLinesByFile.push_back(&I);
}
write(GCOV_TAG_LINES);
write(Len);
write(Number);
llvm::sort(SortedLinesByFile, [](StringMapEntry<GCOVLines> *LHS,
StringMapEntry<GCOVLines> *RHS) {
return LHS->getKey() < RHS->getKey();
});
for (auto &I : SortedLinesByFile)
I->getValue().writeOut();
write(0);
write(0);
}
GCOVBlock(const GCOVBlock &RHS) : GCOVRecord(RHS), Number(RHS.Number) {
// Only allow copy before edges and lines have been added. After that,
// there are inter-block pointers (eg: edges) that won't take kindly to
// blocks being copied or moved around.
assert(LinesByFile.empty());
assert(OutEdges.empty());
}
private:
friend class GCOVFunction;
GCOVBlock(GCOVProfiler *P, uint32_t Number)
: GCOVRecord(P), Number(Number) {}
uint32_t Number;
StringMap<GCOVLines> LinesByFile;
SmallVector<GCOVBlock *, 4> OutEdges;
};
// A function has a unique identifier, a checksum (we leave as zero) and a
// set of blocks and a map of edges between blocks. This is the only GCOV
// object users can construct, the blocks and lines will be rooted here.
class GCOVFunction : public GCOVRecord {
public:
GCOVFunction(GCOVProfiler *P, Function *F, const DISubprogram *SP,
unsigned EndLine, uint32_t Ident, int Version)
: GCOVRecord(P), SP(SP), EndLine(EndLine), Ident(Ident),
Version(Version), ReturnBlock(P, 1) {
LLVM_DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
bool ExitBlockBeforeBody = Version >= 48;
uint32_t i = 0;
for (auto &BB : *F) {
// Skip index 1 if it's assigned to the ReturnBlock.
if (i == 1 && ExitBlockBeforeBody)
++i;
Blocks.insert(std::make_pair(&BB, GCOVBlock(P, i++)));
}
if (!ExitBlockBeforeBody)
ReturnBlock.Number = i;
std::string FunctionNameAndLine;
raw_string_ostream FNLOS(FunctionNameAndLine);
FNLOS << getFunctionName(SP) << SP->getLine();
FNLOS.flush();
FuncChecksum = hash_value(FunctionNameAndLine);
}
GCOVBlock &getBlock(BasicBlock *BB) {
return Blocks.find(BB)->second;
}
GCOVBlock &getReturnBlock() {
return ReturnBlock;
}
std::string getEdgeDestinations() {
std::string EdgeDestinations;
raw_string_ostream EDOS(EdgeDestinations);
Function *F = Blocks.begin()->first->getParent();
for (BasicBlock &I : *F) {
GCOVBlock &Block = getBlock(&I);
for (int i = 0, e = Block.OutEdges.size(); i != e; ++i)
EDOS << Block.OutEdges[i]->Number;
}
return EdgeDestinations;
}
uint32_t getFuncChecksum() const {
return FuncChecksum;
}
void writeOut(uint32_t CfgChecksum) {
write(GCOV_TAG_FUNCTION);
SmallString<128> Filename = getFilename(SP);
uint32_t BlockLen =
2 + (Version >= 47) + wordsOfString(getFunctionName(SP));
if (Version < 80)
BlockLen += wordsOfString(Filename) + 1;
else
BlockLen += 1 + wordsOfString(Filename) + 3 + (Version >= 90);
write(BlockLen);
write(Ident);
write(FuncChecksum);
if (Version >= 47)
write(CfgChecksum);
writeString(getFunctionName(SP));
if (Version < 80) {
writeString(Filename);
write(SP->getLine());
} else {
write(SP->isArtificial()); // artificial
writeString(Filename);
write(SP->getLine()); // start_line
write(0); // start_column
// EndLine is the last line with !dbg. It is not the } line as in GCC,
// but good enough.
write(EndLine);
if (Version >= 90)
write(0); // end_column
}
// Emit count of blocks.
write(GCOV_TAG_BLOCKS);
if (Version < 80) {
write(Blocks.size() + 1);
for (int i = Blocks.size() + 1; i; --i)
write(0);
} else {
write(1);
write(Blocks.size() + 1);
}
LLVM_DEBUG(dbgs() << (Blocks.size() + 1) << " blocks\n");
// Emit edges between blocks.
Function *F = Blocks.begin()->first->getParent();
for (BasicBlock &I : *F) {
GCOVBlock &Block = getBlock(&I);
if (Block.OutEdges.empty()) continue;
write(GCOV_TAG_ARCS);
write(Block.OutEdges.size() * 2 + 1);
write(Block.Number);
for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
LLVM_DEBUG(dbgs() << Block.Number << " -> "
<< Block.OutEdges[i]->Number << "\n");
write(Block.OutEdges[i]->Number);
write(0); // no flags
}
}
// Emit lines for each block.
for (BasicBlock &I : *F)
getBlock(&I).writeOut();
}
private:
const DISubprogram *SP;
unsigned EndLine;
uint32_t Ident;
uint32_t FuncChecksum;
int Version;
DenseMap<BasicBlock *, GCOVBlock> Blocks;
GCOVBlock ReturnBlock;
};
}
// RegexesStr is a string containing differents regex separated by a semi-colon.
// For example "foo\..*$;bar\..*$".
std::vector<Regex> GCOVProfiler::createRegexesFromString(StringRef RegexesStr) {
std::vector<Regex> Regexes;
while (!RegexesStr.empty()) {
std::pair<StringRef, StringRef> HeadTail = RegexesStr.split(';');
if (!HeadTail.first.empty()) {
Regex Re(HeadTail.first);
std::string Err;
if (!Re.isValid(Err)) {
Ctx->emitError(Twine("Regex ") + HeadTail.first +
" is not valid: " + Err);
}
Regexes.emplace_back(std::move(Re));
}
RegexesStr = HeadTail.second;
}
return Regexes;
}
bool GCOVProfiler::doesFilenameMatchARegex(StringRef Filename,
std::vector<Regex> &Regexes) {
for (Regex &Re : Regexes)
if (Re.match(Filename))
return true;
return false;
}
bool GCOVProfiler::isFunctionInstrumented(const Function &F) {
if (FilterRe.empty() && ExcludeRe.empty()) {
return true;
}
SmallString<128> Filename = getFilename(F.getSubprogram());
auto It = InstrumentedFiles.find(Filename);
if (It != InstrumentedFiles.end()) {
return It->second;
}
SmallString<256> RealPath;
StringRef RealFilename;
// Path can be
// /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/*.h so for
// such a case we must get the real_path.
if (sys::fs::real_path(Filename, RealPath)) {
// real_path can fail with path like "foo.c".
RealFilename = Filename;
} else {
RealFilename = RealPath;
}
bool ShouldInstrument;
if (FilterRe.empty()) {
ShouldInstrument = !doesFilenameMatchARegex(RealFilename, ExcludeRe);
} else if (ExcludeRe.empty()) {
ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe);
} else {
ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe) &&
!doesFilenameMatchARegex(RealFilename, ExcludeRe);
}
InstrumentedFiles[Filename] = ShouldInstrument;
return ShouldInstrument;
}
std::string GCOVProfiler::mangleName(const DICompileUnit *CU,
GCovFileType OutputType) {
bool Notes = OutputType == GCovFileType::GCNO;
if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
MDNode *N = GCov->getOperand(i);
bool ThreeElement = N->getNumOperands() == 3;
if (!ThreeElement && N->getNumOperands() != 2)
continue;
if (dyn_cast<MDNode>(N->getOperand(ThreeElement ? 2 : 1)) != CU)
continue;
if (ThreeElement) {
// These nodes have no mangling to apply, it's stored mangled in the
// bitcode.
MDString *NotesFile = dyn_cast<MDString>(N->getOperand(0));
MDString *DataFile = dyn_cast<MDString>(N->getOperand(1));
if (!NotesFile || !DataFile)
continue;
return std::string(Notes ? NotesFile->getString()
: DataFile->getString());
}
MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
if (!GCovFile)
continue;
SmallString<128> Filename = GCovFile->getString();
sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
return std::string(Filename.str());
}
}
SmallString<128> Filename = CU->getFilename();
sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
StringRef FName = sys::path::filename(Filename);
SmallString<128> CurPath;
if (sys::fs::current_path(CurPath))
return std::string(FName);
sys::path::append(CurPath, FName);
return std::string(CurPath.str());
}
bool GCOVProfiler::runOnModule(
Module &M, std::function<const TargetLibraryInfo &(Function &F)> GetTLI) {
this->M = &M;
this->GetTLI = std::move(GetTLI);
Ctx = &M.getContext();
bool Modified = AddFlushBeforeForkAndExec();
FilterRe = createRegexesFromString(Options.Filter);
ExcludeRe = createRegexesFromString(Options.Exclude);
if (Options.EmitNotes) emitProfileNotes();
if (Options.EmitData)
Modified |= emitProfileArcs();
return Modified;
}
PreservedAnalyses GCOVProfilerPass::run(Module &M,
ModuleAnalysisManager &AM) {
GCOVProfiler Profiler(GCOVOpts);
FunctionAnalysisManager &FAM =
AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
if (!Profiler.runOnModule(M, [&](Function &F) -> TargetLibraryInfo & {
return FAM.getResult<TargetLibraryAnalysis>(F);
}))
return PreservedAnalyses::all();
return PreservedAnalyses::none();
}
static bool functionHasLines(const Function &F, unsigned &EndLine) {
// Check whether this function actually has any source lines. Not only
// do these waste space, they also can crash gcov.
EndLine = 0;
for (auto &BB : F) {
for (auto &I : BB) {
// Debug intrinsic locations correspond to the location of the
// declaration, not necessarily any statements or expressions.
if (isa<DbgInfoIntrinsic>(&I)) continue;
const DebugLoc &Loc = I.getDebugLoc();
if (!Loc)
continue;
// Artificial lines such as calls to the global constructors.
if (Loc.getLine() == 0) continue;
EndLine = std::max(EndLine, Loc.getLine());
return true;
}
}
return false;
}
static bool isUsingScopeBasedEH(Function &F) {
if (!F.hasPersonalityFn()) return false;
EHPersonality Personality = classifyEHPersonality(F.getPersonalityFn());
return isScopedEHPersonality(Personality);
}
static bool shouldKeepInEntry(BasicBlock::iterator It) {
if (isa<AllocaInst>(*It)) return true;
if (isa<DbgInfoIntrinsic>(*It)) return true;
if (auto *II = dyn_cast<IntrinsicInst>(It)) {
if (II->getIntrinsicID() == llvm::Intrinsic::localescape) return true;
}
return false;
}
bool GCOVProfiler::AddFlushBeforeForkAndExec() {
SmallVector<CallInst *, 2> Forks;
SmallVector<CallInst *, 2> Execs;
for (auto &F : M->functions()) {
auto *TLI = &GetTLI(F);
for (auto &I : instructions(F)) {
if (CallInst *CI = dyn_cast<CallInst>(&I)) {
if (Function *Callee = CI->getCalledFunction()) {
LibFunc LF;
if (TLI->getLibFunc(*Callee, LF)) {
if (LF == LibFunc_fork) {
#if !defined(_WIN32)
Forks.push_back(CI);
#endif
} else if (LF == LibFunc_execl || LF == LibFunc_execle ||
LF == LibFunc_execlp || LF == LibFunc_execv ||
LF == LibFunc_execvp || LF == LibFunc_execve ||
LF == LibFunc_execvpe || LF == LibFunc_execvP) {
Execs.push_back(CI);
}
}
}
}
}
}
for (auto F : Forks) {
IRBuilder<> Builder(F);
BasicBlock *Parent = F->getParent();
auto NextInst = ++F->getIterator();
// We've a fork so just reset the counters in the child process
FunctionType *FTy = FunctionType::get(Builder.getInt32Ty(), {}, false);
FunctionCallee GCOVFork = M->getOrInsertFunction("__gcov_fork", FTy);
F->setCalledFunction(GCOVFork);
// We split just after the fork to have a counter for the lines after
// Anyway there's a bug:
// void foo() { fork(); }
// void bar() { foo(); blah(); }
// then "blah();" will be called 2 times but showed as 1
// because "blah()" belongs to the same block as "foo();"
Parent->splitBasicBlock(NextInst);
// back() is a br instruction with a debug location
// equals to the one from NextAfterFork
// So to avoid to have two debug locs on two blocks just change it
DebugLoc Loc = F->getDebugLoc();
Parent->back().setDebugLoc(Loc);
}
for (auto E : Execs) {
IRBuilder<> Builder(E);
BasicBlock *Parent = E->getParent();
auto NextInst = ++E->getIterator();
// Since the process is replaced by a new one we need to write out gcdas
// No need to reset the counters since they'll be lost after the exec**
FunctionType *FTy = FunctionType::get(Builder.getVoidTy(), {}, false);
FunctionCallee WriteoutF =
M->getOrInsertFunction("llvm_writeout_files", FTy);
Builder.CreateCall(WriteoutF);
DebugLoc Loc = E->getDebugLoc();
Builder.SetInsertPoint(&*NextInst);
// If the exec** fails we must reset the counters since they've been
// dumped
FunctionCallee ResetF = M->getOrInsertFunction("llvm_reset_counters", FTy);
Builder.CreateCall(ResetF)->setDebugLoc(Loc);
Parent->splitBasicBlock(NextInst);
Parent->back().setDebugLoc(Loc);
}
return !Forks.empty() || !Execs.empty();
}
void GCOVProfiler::emitProfileNotes() {
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes) return;
int Version;
{
uint8_t c3 = Options.Version[0];
uint8_t c2 = Options.Version[1];
uint8_t c1 = Options.Version[2];
Version = c3 >= 'A' ? (c3 - 'A') * 100 + (c2 - '0') * 10 + c1 - '0'
: (c3 - '0') * 10 + c1 - '0';
}
for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
// Each compile unit gets its own .gcno file. This means that whether we run
// this pass over the original .o's as they're produced, or run it after
// LTO, we'll generate the same .gcno files.
auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
// Skip module skeleton (and module) CUs.
if (CU->getDWOId())
continue;
std::error_code EC;
raw_fd_ostream out(mangleName(CU, GCovFileType::GCNO), EC,
sys::fs::OF_None);
if (EC) {
Ctx->emitError(Twine("failed to open coverage notes file for writing: ") +
EC.message());
continue;
}
std::string EdgeDestinations;
Endian = M->getDataLayout().isLittleEndian() ? support::endianness::little
: support::endianness::big;
unsigned FunctionIdent = 0;
for (auto &F : M->functions()) {
DISubprogram *SP = F.getSubprogram();
unsigned EndLine;
if (!SP) continue;
if (!functionHasLines(F, EndLine) || !isFunctionInstrumented(F))
continue;
// TODO: Functions using scope-based EH are currently not supported.
if (isUsingScopeBasedEH(F)) continue;
// gcov expects every function to start with an entry block that has a
// single successor, so split the entry block to make sure of that.
BasicBlock &EntryBlock = F.getEntryBlock();
BasicBlock::iterator It = EntryBlock.begin();
while (shouldKeepInEntry(It))
++It;
EntryBlock.splitBasicBlock(It);
Funcs.push_back(std::make_unique<GCOVFunction>(this, &F, SP, EndLine,
FunctionIdent++, Version));
GCOVFunction &Func = *Funcs.back();
// Add the function line number to the lines of the entry block
// to have a counter for the function definition.
uint32_t Line = SP->getLine();
auto Filename = getFilename(SP);
// Artificial functions such as global initializers
if (!SP->isArtificial())
Func.getBlock(&EntryBlock).getFile(Filename).addLine(Line);
for (auto &BB : F) {
GCOVBlock &Block = Func.getBlock(&BB);
Instruction *TI = BB.getTerminator();
if (int successors = TI->getNumSuccessors()) {
for (int i = 0; i != successors; ++i) {
Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
}
} else if (isa<ReturnInst>(TI)) {
Block.addEdge(Func.getReturnBlock());
}
for (auto &I : BB) {
// Debug intrinsic locations correspond to the location of the
// declaration, not necessarily any statements or expressions.
if (isa<DbgInfoIntrinsic>(&I)) continue;
const DebugLoc &Loc = I.getDebugLoc();
if (!Loc)
continue;
// Artificial lines such as calls to the global constructors.
if (Loc.getLine() == 0 || Loc.isImplicitCode())
continue;
if (Line == Loc.getLine()) continue;
Line = Loc.getLine();
if (SP != getDISubprogram(Loc.getScope()))
continue;
GCOVLines &Lines = Block.getFile(Filename);
Lines.addLine(Loc.getLine());
}
Line = 0;
}
EdgeDestinations += Func.getEdgeDestinations();
}
char Tmp[4];
os = &out;
auto Stamp = static_cast<uint32_t>(hash_value(EdgeDestinations));
FileChecksums.push_back(Stamp);
if (Endian == support::endianness::big) {
out.write("gcno", 4);
out.write(Options.Version, 4);
} else {
out.write("oncg", 4);
std::reverse_copy(Options.Version, Options.Version + 4, Tmp);
out.write(Tmp, 4);
}
write(Stamp);
if (Version >= 90)
writeString(""); // unuseful current_working_directory
if (Version >= 80)
write(0); // unuseful has_unexecuted_blocks
for (auto &Func : Funcs)
Func->writeOut(Stamp);
write(0);
write(0);
out.close();
}
}
bool GCOVProfiler::emitProfileArcs() {
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes) return false;
bool Result = false;
for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
for (auto &F : M->functions()) {
DISubprogram *SP = F.getSubprogram();
unsigned EndLine;
if (!SP) continue;
if (!functionHasLines(F, EndLine) || !isFunctionInstrumented(F))
continue;
// TODO: Functions using scope-based EH are currently not supported.
if (isUsingScopeBasedEH(F)) continue;
DenseMap<std::pair<BasicBlock *, BasicBlock *>, unsigned> EdgeToCounter;
unsigned Edges = 0;
for (auto &BB : F) {
Instruction *TI = BB.getTerminator();
if (isa<ReturnInst>(TI)) {
EdgeToCounter[{&BB, nullptr}] = Edges++;
} else {
for (BasicBlock *Succ : successors(TI)) {
EdgeToCounter[{&BB, Succ}] = Edges++;
}
}
}
ArrayType *CounterTy =
ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
GlobalVariable *Counters =
new GlobalVariable(*M, CounterTy, false,
GlobalValue::InternalLinkage,
Constant::getNullValue(CounterTy),
"__llvm_gcov_ctr");
CountersBySP.push_back(std::make_pair(Counters, SP));
// If a BB has several predecessors, use a PHINode to select
// the correct counter.
for (auto &BB : F) {
const unsigned EdgeCount =
std::distance(pred_begin(&BB), pred_end(&BB));
if (EdgeCount) {
// The phi node must be at the begin of the BB.
IRBuilder<> BuilderForPhi(&*BB.begin());
Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
PHINode *Phi = BuilderForPhi.CreatePHI(Int64PtrTy, EdgeCount);
for (BasicBlock *Pred : predecessors(&BB)) {
auto It = EdgeToCounter.find({Pred, &BB});
assert(It != EdgeToCounter.end());
const unsigned Edge = It->second;
Value *EdgeCounter = BuilderForPhi.CreateConstInBoundsGEP2_64(
Counters->getValueType(), Counters, 0, Edge);
Phi->addIncoming(EdgeCounter, Pred);
}
// Skip phis, landingpads.
IRBuilder<> Builder(&*BB.getFirstInsertionPt());
Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Phi);
Count = Builder.CreateAdd(Count, Builder.getInt64(1));
Builder.CreateStore(Count, Phi);
Instruction *TI = BB.getTerminator();
if (isa<ReturnInst>(TI)) {
auto It = EdgeToCounter.find({&BB, nullptr});
assert(It != EdgeToCounter.end());
const unsigned Edge = It->second;
Value *Counter = Builder.CreateConstInBoundsGEP2_64(
Counters->getValueType(), Counters, 0, Edge);
Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Counter);
Count = Builder.CreateAdd(Count, Builder.getInt64(1));
Builder.CreateStore(Count, Counter);
}
}
}
}
Function *WriteoutF = insertCounterWriteout(CountersBySP);
Function *ResetF = insertReset(CountersBySP);
// Create a small bit of code that registers the "__llvm_gcov_writeout" to
// be executed at exit and the "__llvm_gcov_flush" function to be executed
// when "__gcov_flush" is called.
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
"__llvm_gcov_init", M);
F->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
F->setLinkage(GlobalValue::InternalLinkage);
F->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
F->addFnAttr(Attribute::NoRedZone);
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
IRBuilder<> Builder(BB);
FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
auto *PFTy = PointerType::get(FTy, 0);
FTy = FunctionType::get(Builder.getVoidTy(), {PFTy, PFTy}, false);
// Initialize the environment and register the local writeout, flush and
// reset functions.
FunctionCallee GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
Builder.CreateCall(GCOVInit, {WriteoutF, ResetF});
Builder.CreateRetVoid();
appendToGlobalCtors(*M, F, 0);
Result = true;
}
return Result;
}
FunctionCallee GCOVProfiler::getStartFileFunc(const TargetLibraryInfo *TLI) {
Type *Args[] = {
Type::getInt8PtrTy(*Ctx), // const char *orig_filename
Type::getInt32Ty(*Ctx), // uint32_t version
Type::getInt32Ty(*Ctx), // uint32_t checksum
};
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
AttributeList AL;
if (auto AK = TLI->getExtAttrForI32Param(false))
AL = AL.addParamAttribute(*Ctx, 2, AK);
FunctionCallee Res = M->getOrInsertFunction("llvm_gcda_start_file", FTy, AL);
return Res;
}
FunctionCallee GCOVProfiler::getEmitFunctionFunc(const TargetLibraryInfo *TLI) {
Type *Args[] = {
Type::getInt32Ty(*Ctx), // uint32_t ident
Type::getInt32Ty(*Ctx), // uint32_t func_checksum
Type::getInt32Ty(*Ctx), // uint32_t cfg_checksum
};
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
AttributeList AL;
if (auto AK = TLI->getExtAttrForI32Param(false)) {
AL = AL.addParamAttribute(*Ctx, 0, AK);
AL = AL.addParamAttribute(*Ctx, 1, AK);
AL = AL.addParamAttribute(*Ctx, 2, AK);
}
return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
}
FunctionCallee GCOVProfiler::getEmitArcsFunc(const TargetLibraryInfo *TLI) {
Type *Args[] = {
Type::getInt32Ty(*Ctx), // uint32_t num_counters
Type::getInt64PtrTy(*Ctx), // uint64_t *counters
};
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
AttributeList AL;
if (auto AK = TLI->getExtAttrForI32Param(false))
AL = AL.addParamAttribute(*Ctx, 0, AK);
return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy, AL);
}
FunctionCallee GCOVProfiler::getSummaryInfoFunc() {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
}
FunctionCallee GCOVProfiler::getEndFileFunc() {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
}
Function *GCOVProfiler::insertCounterWriteout(
ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
if (!WriteoutF)
WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
"__llvm_gcov_writeout", M);
WriteoutF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
WriteoutF->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
WriteoutF->addFnAttr(Attribute::NoRedZone);
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
IRBuilder<> Builder(BB);
auto *TLI = &GetTLI(*WriteoutF);
FunctionCallee StartFile = getStartFileFunc(TLI);
FunctionCallee EmitFunction = getEmitFunctionFunc(TLI);
FunctionCallee EmitArcs = getEmitArcsFunc(TLI);
FunctionCallee SummaryInfo = getSummaryInfoFunc();
FunctionCallee EndFile = getEndFileFunc();
NamedMDNode *CUNodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CUNodes) {
Builder.CreateRetVoid();
return WriteoutF;
}
// Collect the relevant data into a large constant data structure that we can
// walk to write out everything.
StructType *StartFileCallArgsTy = StructType::create(
{Builder.getInt8PtrTy(), Builder.getInt32Ty(), Builder.getInt32Ty()});
StructType *EmitFunctionCallArgsTy = StructType::create(
{Builder.getInt32Ty(), Builder.getInt32Ty(), Builder.getInt32Ty()});
StructType *EmitArcsCallArgsTy = StructType::create(
{Builder.getInt32Ty(), Builder.getInt64Ty()->getPointerTo()});
StructType *FileInfoTy =
StructType::create({StartFileCallArgsTy, Builder.getInt32Ty(),
EmitFunctionCallArgsTy->getPointerTo(),
EmitArcsCallArgsTy->getPointerTo()});
Constant *Zero32 = Builder.getInt32(0);
// Build an explicit array of two zeros for use in ConstantExpr GEP building.
Constant *TwoZero32s[] = {Zero32, Zero32};
SmallVector<Constant *, 8> FileInfos;
for (int i : llvm::seq<int>(0, CUNodes->getNumOperands())) {
auto *CU = cast<DICompileUnit>(CUNodes->getOperand(i));
// Skip module skeleton (and module) CUs.
if (CU->getDWOId())
continue;
std::string FilenameGcda = mangleName(CU, GCovFileType::GCDA);
uint32_t CfgChecksum = FileChecksums.empty() ? 0 : FileChecksums[i];
auto *StartFileCallArgs = ConstantStruct::get(
StartFileCallArgsTy,
{Builder.CreateGlobalStringPtr(FilenameGcda),
Builder.getInt32(endian::read32be(Options.Version)),
Builder.getInt32(CfgChecksum)});
SmallVector<Constant *, 8> EmitFunctionCallArgsArray;
SmallVector<Constant *, 8> EmitArcsCallArgsArray;
for (int j : llvm::seq<int>(0, CountersBySP.size())) {
uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
EmitFunctionCallArgsArray.push_back(ConstantStruct::get(
EmitFunctionCallArgsTy,
{Builder.getInt32(j),
Builder.getInt32(FuncChecksum),
Builder.getInt32(CfgChecksum)}));
GlobalVariable *GV = CountersBySP[j].first;
unsigned Arcs = cast<ArrayType>(GV->getValueType())->getNumElements();
EmitArcsCallArgsArray.push_back(ConstantStruct::get(
EmitArcsCallArgsTy,
{Builder.getInt32(Arcs), ConstantExpr::getInBoundsGetElementPtr(
GV->getValueType(), GV, TwoZero32s)}));
}
// Create global arrays for the two emit calls.
int CountersSize = CountersBySP.size();
assert(CountersSize == (int)EmitFunctionCallArgsArray.size() &&
"Mismatched array size!");
assert(CountersSize == (int)EmitArcsCallArgsArray.size() &&
"Mismatched array size!");
auto *EmitFunctionCallArgsArrayTy =
ArrayType::get(EmitFunctionCallArgsTy, CountersSize);
auto *EmitFunctionCallArgsArrayGV = new GlobalVariable(
*M, EmitFunctionCallArgsArrayTy, /*isConstant*/ true,
GlobalValue::InternalLinkage,
ConstantArray::get(EmitFunctionCallArgsArrayTy,
EmitFunctionCallArgsArray),
Twine("__llvm_internal_gcov_emit_function_args.") + Twine(i));
auto *EmitArcsCallArgsArrayTy =
ArrayType::get(EmitArcsCallArgsTy, CountersSize);
EmitFunctionCallArgsArrayGV->setUnnamedAddr(
GlobalValue::UnnamedAddr::Global);
auto *EmitArcsCallArgsArrayGV = new GlobalVariable(
*M, EmitArcsCallArgsArrayTy, /*isConstant*/ true,
GlobalValue::InternalLinkage,
ConstantArray::get(EmitArcsCallArgsArrayTy, EmitArcsCallArgsArray),
Twine("__llvm_internal_gcov_emit_arcs_args.") + Twine(i));
EmitArcsCallArgsArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
FileInfos.push_back(ConstantStruct::get(
FileInfoTy,
{StartFileCallArgs, Builder.getInt32(CountersSize),
ConstantExpr::getInBoundsGetElementPtr(EmitFunctionCallArgsArrayTy,
EmitFunctionCallArgsArrayGV,
TwoZero32s),
ConstantExpr::getInBoundsGetElementPtr(
EmitArcsCallArgsArrayTy, EmitArcsCallArgsArrayGV, TwoZero32s)}));
}
// If we didn't find anything to actually emit, bail on out.
if (FileInfos.empty()) {
Builder.CreateRetVoid();
return WriteoutF;
}
// To simplify code, we cap the number of file infos we write out to fit
// easily in a 32-bit signed integer. This gives consistent behavior between
// 32-bit and 64-bit systems without requiring (potentially very slow) 64-bit
// operations on 32-bit systems. It also seems unreasonable to try to handle
// more than 2 billion files.
if ((int64_t)FileInfos.size() > (int64_t)INT_MAX)
FileInfos.resize(INT_MAX);
// Create a global for the entire data structure so we can walk it more
// easily.
auto *FileInfoArrayTy = ArrayType::get(FileInfoTy, FileInfos.size());
auto *FileInfoArrayGV = new GlobalVariable(
*M, FileInfoArrayTy, /*isConstant*/ true, GlobalValue::InternalLinkage,
ConstantArray::get(FileInfoArrayTy, FileInfos),
"__llvm_internal_gcov_emit_file_info");
FileInfoArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
// Create the CFG for walking this data structure.
auto *FileLoopHeader =
BasicBlock::Create(*Ctx, "file.loop.header", WriteoutF);
auto *CounterLoopHeader =
BasicBlock::Create(*Ctx, "counter.loop.header", WriteoutF);
auto *FileLoopLatch = BasicBlock::Create(*Ctx, "file.loop.latch", WriteoutF);
auto *ExitBB = BasicBlock::Create(*Ctx, "exit", WriteoutF);
// We always have at least one file, so just branch to the header.
Builder.CreateBr(FileLoopHeader);
// The index into the files structure is our loop induction variable.
Builder.SetInsertPoint(FileLoopHeader);
PHINode *IV =
Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
IV->addIncoming(Builder.getInt32(0), BB);
auto *FileInfoPtr = Builder.CreateInBoundsGEP(
FileInfoArrayTy, FileInfoArrayGV, {Builder.getInt32(0), IV});
auto *StartFileCallArgsPtr =
Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 0);
auto *StartFileCall = Builder.CreateCall(
StartFile,
{Builder.CreateLoad(StartFileCallArgsTy->getElementType(0),
Builder.CreateStructGEP(StartFileCallArgsTy,
StartFileCallArgsPtr, 0)),
Builder.CreateLoad(StartFileCallArgsTy->getElementType(1),
Builder.CreateStructGEP(StartFileCallArgsTy,
StartFileCallArgsPtr, 1)),
Builder.CreateLoad(StartFileCallArgsTy->getElementType(2),
Builder.CreateStructGEP(StartFileCallArgsTy,
StartFileCallArgsPtr, 2))});
if (auto AK = TLI->getExtAttrForI32Param(false))
StartFileCall->addParamAttr(2, AK);
auto *NumCounters =
Builder.CreateLoad(FileInfoTy->getElementType(1),
Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 1));
auto *EmitFunctionCallArgsArray =
Builder.CreateLoad(FileInfoTy->getElementType(2),
Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 2));
auto *EmitArcsCallArgsArray =
Builder.CreateLoad(FileInfoTy->getElementType(3),
Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 3));
auto *EnterCounterLoopCond =
Builder.CreateICmpSLT(Builder.getInt32(0), NumCounters);
Builder.CreateCondBr(EnterCounterLoopCond, CounterLoopHeader, FileLoopLatch);
Builder.SetInsertPoint(CounterLoopHeader);
auto *JV = Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
JV->addIncoming(Builder.getInt32(0), FileLoopHeader);
auto *EmitFunctionCallArgsPtr = Builder.CreateInBoundsGEP(
EmitFunctionCallArgsTy, EmitFunctionCallArgsArray, JV);
auto *EmitFunctionCall = Builder.CreateCall(
EmitFunction,
{Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(0),
Builder.CreateStructGEP(EmitFunctionCallArgsTy,
EmitFunctionCallArgsPtr, 0)),
Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(1),
Builder.CreateStructGEP(EmitFunctionCallArgsTy,
EmitFunctionCallArgsPtr, 1)),
Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(2),
Builder.CreateStructGEP(EmitFunctionCallArgsTy,
EmitFunctionCallArgsPtr,
2))});
if (auto AK = TLI->getExtAttrForI32Param(false)) {
EmitFunctionCall->addParamAttr(0, AK);
EmitFunctionCall->addParamAttr(1, AK);
EmitFunctionCall->addParamAttr(2, AK);
}
auto *EmitArcsCallArgsPtr =
Builder.CreateInBoundsGEP(EmitArcsCallArgsTy, EmitArcsCallArgsArray, JV);
auto *EmitArcsCall = Builder.CreateCall(
EmitArcs,
{Builder.CreateLoad(
EmitArcsCallArgsTy->getElementType(0),
Builder.CreateStructGEP(EmitArcsCallArgsTy, EmitArcsCallArgsPtr, 0)),
Builder.CreateLoad(EmitArcsCallArgsTy->getElementType(1),
Builder.CreateStructGEP(EmitArcsCallArgsTy,
EmitArcsCallArgsPtr, 1))});
if (auto AK = TLI->getExtAttrForI32Param(false))
EmitArcsCall->addParamAttr(0, AK);
auto *NextJV = Builder.CreateAdd(JV, Builder.getInt32(1));
auto *CounterLoopCond = Builder.CreateICmpSLT(NextJV, NumCounters);
Builder.CreateCondBr(CounterLoopCond, CounterLoopHeader, FileLoopLatch);
JV->addIncoming(NextJV, CounterLoopHeader);
Builder.SetInsertPoint(FileLoopLatch);
Builder.CreateCall(SummaryInfo, {});
Builder.CreateCall(EndFile, {});
auto *NextIV = Builder.CreateAdd(IV, Builder.getInt32(1));
auto *FileLoopCond =
Builder.CreateICmpSLT(NextIV, Builder.getInt32(FileInfos.size()));
Builder.CreateCondBr(FileLoopCond, FileLoopHeader, ExitBB);
IV->addIncoming(NextIV, FileLoopLatch);
Builder.SetInsertPoint(ExitBB);
Builder.CreateRetVoid();
return WriteoutF;
}
Function *GCOVProfiler::insertReset(
ArrayRef<std::pair<GlobalVariable *, MDNode *>> CountersBySP) {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
Function *ResetF = M->getFunction("__llvm_gcov_reset");
if (!ResetF)
ResetF = Function::Create(FTy, GlobalValue::InternalLinkage,
"__llvm_gcov_reset", M);
ResetF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
ResetF->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
ResetF->addFnAttr(Attribute::NoRedZone);
BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", ResetF);
IRBuilder<> Builder(Entry);
// Zero out the counters.
for (const auto &I : CountersBySP) {
GlobalVariable *GV = I.first;
Constant *Null = Constant::getNullValue(GV->getValueType());
Builder.CreateStore(Null, GV);
}
Type *RetTy = ResetF->getReturnType();
if (RetTy->isVoidTy())
Builder.CreateRetVoid();
else if (RetTy->isIntegerTy())
// Used if __llvm_gcov_reset was implicitly declared.
Builder.CreateRet(ConstantInt::get(RetTy, 0));
else
report_fatal_error("invalid return type for __llvm_gcov_reset");
return ResetF;
}
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