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

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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;
#define DEBUG_TYPE "insert-gcov-profiling"
static cl::opt<std::string>
DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
cl::ValueRequired);
static cl::opt<bool> DefaultExitBlockBeforeBody("gcov-exit-block-before-body",
cl::init(false), cl::Hidden);
GCOVOptions GCOVOptions::getDefault() {
GCOVOptions Options;
Options.EmitNotes = true;
Options.EmitData = true;
Options.UseCfgChecksum = false;
Options.NoRedZone = false;
Options.FunctionNamesInData = true;
Options.ExitBlockBeforeBody = DefaultExitBlockBeforeBody;
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) {
assert((Options.EmitNotes || Options.EmitData) &&
"GCOVProfiler asked to do nothing?");
ReversedVersion[0] = Options.Version[3];
ReversedVersion[1] = Options.Version[2];
ReversedVersion[2] = Options.Version[1];
ReversedVersion[3] = Options.Version[0];
ReversedVersion[4] = '\0';
}
bool
runOnModule(Module &M,
std::function<const TargetLibraryInfo &(Function &F)> GetTLI);
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 *insertFlush(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
void AddFlushBeforeForkAndExec();
enum class GCovFileType { GCNO, GCDA };
std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
GCOVOptions Options;
// Reversed, NUL-terminated copy of Options.Version.
char ReversedVersion[5];
// 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:
static const char *const LinesTag;
static const char *const FunctionTag;
static const char *const BlockTag;
static const char *const EdgeTag;
GCOVRecord() = default;
void writeBytes(const char *Bytes, int Size) {
os->write(Bytes, Size);
}
void write(uint32_t i) {
writeBytes(reinterpret_cast<char*>(&i), 4);
}
// Returns the length measured in 4-byte blocks that will be used to
// represent this string in a GCOV file
static unsigned lengthOfGCOVString(StringRef s) {
// A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
// padding out to the next 4-byte word. The length is measured in 4-byte
// words including padding, not bytes of actual string.
return (s.size() / 4) + 1;
}
void writeGCOVString(StringRef s) {
uint32_t Len = lengthOfGCOVString(s);
write(Len);
writeBytes(s.data(), s.size());
// Write 1 to 4 bytes of NUL padding.
assert((unsigned)(4 - (s.size() % 4)) > 0);
assert((unsigned)(4 - (s.size() % 4)) <= 4);
writeBytes("\0\0\0\0", 4 - (s.size() % 4));
}
raw_ostream *os;
};
const char *const GCOVRecord::LinesTag = "\0\0\x45\x01";
const char *const GCOVRecord::FunctionTag = "\0\0\0\1";
const char *const GCOVRecord::BlockTag = "\0\0\x41\x01";
const char *const GCOVRecord::EdgeTag = "\0\0\x43\x01";
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 {
// Here 2 = 1 for string length + 1 for '0' id#.
return lengthOfGCOVString(Filename) + 2 + Lines.size();
}
void writeOut() {
write(0);
writeGCOVString(Filename);
for (int i = 0, e = Lines.size(); i != e; ++i)
write(Lines[i]);
}
GCOVLines(StringRef F, raw_ostream *os)
: Filename(F) {
this->os = os;
}
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, Filename, os).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);
}
writeBytes(LinesTag, 4);
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(uint32_t Number, raw_ostream *os)
: Number(Number) {
this->os = os;
}
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(const DISubprogram *SP, Function *F, raw_ostream *os,
uint32_t Ident, bool UseCfgChecksum, bool ExitBlockBeforeBody)
: SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0),
ReturnBlock(1, os) {
this->os = os;
LLVM_DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
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(i++, os)));
}
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 setCfgChecksum(uint32_t Checksum) {
CfgChecksum = Checksum;
}
void writeOut() {
writeBytes(FunctionTag, 4);
SmallString<128> Filename = getFilename(SP);
uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
1 + lengthOfGCOVString(Filename) + 1;
if (UseCfgChecksum)
++BlockLen;
write(BlockLen);
write(Ident);
write(FuncChecksum);
if (UseCfgChecksum)
write(CfgChecksum);
writeGCOVString(getFunctionName(SP));
writeGCOVString(Filename);
write(SP->getLine());
// Emit count of blocks.
writeBytes(BlockTag, 4);
write(Blocks.size() + 1);
for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
write(0); // No flags on our blocks.
}
LLVM_DEBUG(dbgs() << Blocks.size() << " blocks.\n");
// Emit edges between blocks.
if (Blocks.empty()) return;
Function *F = Blocks.begin()->first->getParent();
for (BasicBlock &I : *F) {
GCOVBlock &Block = getBlock(&I);
if (Block.OutEdges.empty()) continue;
writeBytes(EdgeTag, 4);
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;
uint32_t Ident;
uint32_t FuncChecksum;
bool UseCfgChecksum;
uint32_t CfgChecksum;
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 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 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 FName;
sys::path::append(CurPath, FName);
return 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();
AddFlushBeforeForkAndExec();
FilterRe = createRegexesFromString(Options.Filter);
ExcludeRe = createRegexesFromString(Options.Exclude);
if (Options.EmitNotes) emitProfileNotes();
if (Options.EmitData) return emitProfileArcs();
return false;
}
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(Function &F) {
// Check whether this function actually has any source lines. Not only
// do these waste space, they also can crash gcov.
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;
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;
}
void GCOVProfiler::AddFlushBeforeForkAndExec() {
SmallVector<Instruction *, 2> ForkAndExecs;
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) &&
(LF == LibFunc_fork || LF == LibFunc_execl ||
LF == LibFunc_execle || LF == LibFunc_execlp ||
LF == LibFunc_execv || LF == LibFunc_execvp ||
LF == LibFunc_execve || LF == LibFunc_execvpe ||
LF == LibFunc_execvP)) {
ForkAndExecs.push_back(&I);
}
}
}
}
}
// We need to split the block after the fork/exec call
// because else the counters for the lines after will be
// the same as before the call.
for (auto I : ForkAndExecs) {
IRBuilder<> Builder(I);
FunctionType *FTy = FunctionType::get(Builder.getVoidTy(), {}, false);
FunctionCallee GCOVFlush = M->getOrInsertFunction("__gcov_flush", FTy);
Builder.CreateCall(GCOVFlush);
I->getParent()->splitBasicBlock(I);
}
}
void GCOVProfiler::emitProfileNotes() {
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes) return;
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;
unsigned FunctionIdent = 0;
for (auto &F : M->functions()) {
DISubprogram *SP = F.getSubprogram();
if (!SP) continue;
if (!functionHasLines(F) || !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>(SP, &F, &out, FunctionIdent++,
Options.UseCfgChecksum,
Options.ExitBlockBeforeBody));
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();
}
FileChecksums.push_back(hash_value(EdgeDestinations));
out.write("oncg", 4);
out.write(ReversedVersion, 4);
out.write(reinterpret_cast<char*>(&FileChecksums.back()), 4);
for (auto &Func : Funcs) {
Func->setCfgChecksum(FileChecksums.back());
Func->writeOut();
}
out.write("\0\0\0\0\0\0\0\0", 8); // EOF
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();
if (!SP) continue;
if (!functionHasLines(F) || !isFunctionInstrumented(F))
continue;
// TODO: Functions using scope-based EH are currently not supported.
if (isUsingScopeBasedEH(F)) continue;
if (!Result) Result = true;
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 *FlushF = insertFlush(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);
Type *Params[] = {
PointerType::get(FTy, 0),
PointerType::get(FTy, 0)
};
FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
// Initialize the environment and register the local writeout and flush
// functions.
FunctionCallee GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
Builder.CreateCall(GCOVInit, {WriteoutF, FlushF});
Builder.CreateRetVoid();
appendToGlobalCtors(*M, F, 0);
}
return Result;
}
FunctionCallee GCOVProfiler::getStartFileFunc(const TargetLibraryInfo *TLI) {
Type *Args[] = {
Type::getInt8PtrTy(*Ctx), // const char *orig_filename
Type::getInt8PtrTy(*Ctx), // const char version[4]
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::getInt8PtrTy(*Ctx), // const char *function_name
Type::getInt32Ty(*Ctx), // uint32_t func_checksum
Type::getInt8Ty(*Ctx), // uint8_t use_extra_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, 2, AK);
AL = AL.addParamAttribute(*Ctx, 3, AK);
AL = AL.addParamAttribute(*Ctx, 4, 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.getInt8PtrTy(), Builder.getInt32Ty()});
StructType *EmitFunctionCallArgsTy = StructType::create(
{Builder.getInt32Ty(), Builder.getInt8PtrTy(), Builder.getInt32Ty(),
Builder.getInt8Ty(), 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.CreateGlobalStringPtr(ReversedVersion),
Builder.getInt32(CfgChecksum)});
SmallVector<Constant *, 8> EmitFunctionCallArgsArray;
SmallVector<Constant *, 8> EmitArcsCallArgsArray;
for (int j : llvm::seq<int>(0, CountersBySP.size())) {
auto *SP = cast_or_null<DISubprogram>(CountersBySP[j].second);
uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
EmitFunctionCallArgsArray.push_back(ConstantStruct::get(
EmitFunctionCallArgsTy,
{Builder.getInt32(j),
Options.FunctionNamesInData
? Builder.CreateGlobalStringPtr(getFunctionName(SP))
: Constant::getNullValue(Builder.getInt8PtrTy()),
Builder.getInt32(FuncChecksum),
Builder.getInt8(Options.UseCfgChecksum),
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)),
Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(3),
Builder.CreateStructGEP(EmitFunctionCallArgsTy,
EmitFunctionCallArgsPtr, 3)),
Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(4),
Builder.CreateStructGEP(EmitFunctionCallArgsTy,
EmitFunctionCallArgsPtr,
4))});
if (auto AK = TLI->getExtAttrForI32Param(false)) {
EmitFunctionCall->addParamAttr(0, AK);
EmitFunctionCall->addParamAttr(2, AK);
EmitFunctionCall->addParamAttr(3, AK);
EmitFunctionCall->addParamAttr(4, 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::
insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
Function *FlushF = M->getFunction("__llvm_gcov_flush");
if (!FlushF)
FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
"__llvm_gcov_flush", M);
else
FlushF->setLinkage(GlobalValue::InternalLinkage);
FlushF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
FlushF->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
FlushF->addFnAttr(Attribute::NoRedZone);
BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
// Write out the current counters.
Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
assert(WriteoutF && "Need to create the writeout function first!");
IRBuilder<> Builder(Entry);
Builder.CreateCall(WriteoutF, {});
// 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 = FlushF->getReturnType();
if (RetTy == Type::getVoidTy(*Ctx))
Builder.CreateRetVoid();
else if (RetTy->isIntegerTy())
// Used if __llvm_gcov_flush was implicitly declared.
Builder.CreateRet(ConstantInt::get(RetTy, 0));
else
report_fatal_error("invalid return type for __llvm_gcov_flush");
return FlushF;
}
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