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llvm-mirror/lib/Transforms/Instrumentation/GCOVProfiling.cpp
Alp Toker fd9ead3b6f Introduce a string_ostream string builder facilty 
string_ostream is a safe and efficient string builder that combines opaque
stack storage with a built-in ostream interface.

small_string_ostream<bytes> additionally permits an explicit stack storage size
other than the default 128 bytes to be provided. Beyond that, storage is
transferred to the heap.

This convenient class can be used in most places an
std::string+raw_string_ostream pair or SmallString<>+raw_svector_ostream pair
would previously have been used, in order to guarantee consistent access
without byte truncation.

The patch also converts much of LLVM to use the new facility. These changes
include several probable bug fixes for truncated output, a programming error
that's no longer possible with the new interface.

llvm-svn: 211749
2014-06-26 00:00:48 +00:00

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//===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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/Transforms/Instrumentation.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/UniqueVector.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/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/raw_ostream.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);
GCOVOptions GCOVOptions::getDefault() {
GCOVOptions Options;
Options.EmitNotes = true;
Options.EmitData = true;
Options.UseCfgChecksum = false;
Options.NoRedZone = false;
Options.FunctionNamesInData = true;
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 ModulePass {
public:
static char ID;
GCOVProfiler() : ModulePass(ID), Options(GCOVOptions::getDefault()) {
init();
}
GCOVProfiler(const GCOVOptions &Options) : ModulePass(ID), Options(Options){
assert((Options.EmitNotes || Options.EmitData) &&
"GCOVProfiler asked to do nothing?");
init();
}
const char *getPassName() const override {
return "GCOV Profiler";
}
private:
void init() {
ReversedVersion[0] = Options.Version[3];
ReversedVersion[1] = Options.Version[2];
ReversedVersion[2] = Options.Version[1];
ReversedVersion[3] = Options.Version[0];
ReversedVersion[4] = '\0';
initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module &M) override;
// 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();
// Get pointers to the functions in the runtime library.
Constant *getStartFileFunc();
Constant *getIncrementIndirectCounterFunc();
Constant *getEmitFunctionFunc();
Constant *getEmitArcsFunc();
Constant *getSummaryInfoFunc();
Constant *getDeleteWriteoutFunctionListFunc();
Constant *getDeleteFlushFunctionListFunc();
Constant *getEndFileFunc();
// Create or retrieve an i32 state value that is used to represent the
// pred block number for certain non-trivial edges.
GlobalVariable *getEdgeStateValue();
// Produce a table of pointers to counters, by predecessor and successor
// block number.
GlobalVariable *buildEdgeLookupTable(Function *F,
GlobalVariable *Counter,
const UniqueVector<BasicBlock *>&Preds,
const UniqueVector<BasicBlock*>&Succs);
// 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 insertIndirectCounterIncrement();
std::string mangleName(DICompileUnit CU, const char *NewStem);
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;
LLVMContext *Ctx;
SmallVector<std::unique_ptr<GCOVFunction>, 16> Funcs;
};
}
char GCOVProfiler::ID = 0;
INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
"Insert instrumentation for GCOV profiling", false, false)
ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
return new GCOVProfiler(Options);
}
static StringRef getFunctionName(DISubprogram SP) {
if (!SP.getLinkageName().empty())
return SP.getLinkageName();
return SP.getName();
}
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() {}
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:
StringRef 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) {
GCOVLines *&Lines = LinesByFile[Filename];
if (!Lines) {
Lines = new GCOVLines(Filename, os);
}
return *Lines;
}
void addEdge(GCOVBlock &Successor) {
OutEdges.push_back(&Successor);
}
void writeOut() {
uint32_t Len = 3;
SmallVector<StringMapEntry<GCOVLines *> *, 32> SortedLinesByFile;
for (StringMap<GCOVLines *>::iterator I = LinesByFile.begin(),
E = LinesByFile.end(); I != E; ++I) {
Len += I->second->length();
SortedLinesByFile.push_back(&*I);
}
writeBytes(LinesTag, 4);
write(Len);
write(Number);
std::sort(SortedLinesByFile.begin(), SortedLinesByFile.end(),
[](StringMapEntry<GCOVLines *> *LHS,
StringMapEntry<GCOVLines *> *RHS) {
return LHS->getKey() < RHS->getKey();
});
for (SmallVectorImpl<StringMapEntry<GCOVLines *> *>::iterator
I = SortedLinesByFile.begin(), E = SortedLinesByFile.end();
I != E; ++I)
(*I)->getValue()->writeOut();
write(0);
write(0);
}
~GCOVBlock() {
DeleteContainerSeconds(LinesByFile);
}
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(DISubprogram SP, raw_ostream *os, uint32_t Ident,
bool UseCfgChecksum) :
SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0) {
this->os = os;
Function *F = SP.getFunction();
DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
uint32_t i = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
Blocks[BB] = new GCOVBlock(i++, os);
}
ReturnBlock = new GCOVBlock(i++, os);
string_ostream FnNameLine;
FnNameLine << getFunctionName(SP) << SP.getLineNumber();
FuncChecksum = hash_value(FnNameLine.str());
}
~GCOVFunction() {
DeleteContainerSeconds(Blocks);
delete ReturnBlock;
}
GCOVBlock &getBlock(BasicBlock *BB) {
return *Blocks[BB];
}
GCOVBlock &getReturnBlock() {
return *ReturnBlock;
}
std::string getEdgeDestinations() {
string_ostream EdgeDestinations;
Function *F = Blocks.begin()->first->getParent();
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
GCOVBlock &Block = *Blocks[I];
for (int i = 0, e = Block.OutEdges.size(); i != e; ++i)
EdgeDestinations << Block.OutEdges[i]->Number;
}
return EdgeDestinations.str();
}
uint32_t getFuncChecksum() {
return FuncChecksum;
}
void setCfgChecksum(uint32_t Checksum) {
CfgChecksum = Checksum;
}
void writeOut() {
writeBytes(FunctionTag, 4);
uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
1 + lengthOfGCOVString(SP.getFilename()) + 1;
if (UseCfgChecksum)
++BlockLen;
write(BlockLen);
write(Ident);
write(FuncChecksum);
if (UseCfgChecksum)
write(CfgChecksum);
writeGCOVString(getFunctionName(SP));
writeGCOVString(SP.getFilename());
write(SP.getLineNumber());
// 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.
}
DEBUG(dbgs() << Blocks.size() << " blocks.\n");
// Emit edges between blocks.
if (Blocks.empty()) return;
Function *F = Blocks.begin()->first->getParent();
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
GCOVBlock &Block = *Blocks[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) {
DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
<< "\n");
write(Block.OutEdges[i]->Number);
write(0); // no flags
}
}
// Emit lines for each block.
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
Blocks[I]->writeOut();
}
}
private:
DISubprogram SP;
uint32_t Ident;
uint32_t FuncChecksum;
bool UseCfgChecksum;
uint32_t CfgChecksum;
DenseMap<BasicBlock *, GCOVBlock *> Blocks;
GCOVBlock *ReturnBlock;
};
}
std::string GCOVProfiler::mangleName(DICompileUnit CU, const char *NewStem) {
if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
MDNode *N = GCov->getOperand(i);
if (N->getNumOperands() != 2) continue;
MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
MDNode *CompileUnit = dyn_cast<MDNode>(N->getOperand(1));
if (!GCovFile || !CompileUnit) continue;
if (CompileUnit == CU) {
SmallString<128> Filename = GCovFile->getString();
sys::path::replace_extension(Filename, NewStem);
return Filename.str();
}
}
}
SmallString<128> Filename = CU.getFilename();
sys::path::replace_extension(Filename, NewStem);
StringRef FName = sys::path::filename(Filename);
SmallString<128> CurPath;
if (sys::fs::current_path(CurPath)) return FName;
sys::path::append(CurPath, FName.str());
return CurPath.str();
}
bool GCOVProfiler::runOnModule(Module &M) {
this->M = &M;
Ctx = &M.getContext();
if (Options.EmitNotes) emitProfileNotes();
if (Options.EmitData) return emitProfileArcs();
return false;
}
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 (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
I != IE; ++I) {
// 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.isUnknown()) continue;
// Artificial lines such as calls to the global constructors.
if (Loc.getLine() == 0) continue;
return true;
}
}
return false;
}
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.
DICompileUnit CU(CU_Nodes->getOperand(i));
std::string ErrorInfo;
raw_fd_ostream out(mangleName(CU, "gcno").c_str(), ErrorInfo,
sys::fs::F_None);
std::string EdgeDestinations;
DIArray SPs = CU.getSubprograms();
for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
DISubprogram SP(SPs.getElement(i));
assert((!SP || SP.isSubprogram()) &&
"A MDNode in subprograms of a CU should be null or a DISubprogram.");
if (!SP)
continue;
Function *F = SP.getFunction();
if (!F) continue;
if (!functionHasLines(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 (isa<AllocaInst>(*It) || isa<DbgInfoIntrinsic>(*It))
++It;
EntryBlock.splitBasicBlock(It);
Funcs.push_back(
make_unique<GCOVFunction>(SP, &out, i, Options.UseCfgChecksum));
GCOVFunction &Func = *Funcs.back();
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
GCOVBlock &Block = Func.getBlock(BB);
TerminatorInst *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());
}
uint32_t Line = 0;
for (BasicBlock::iterator I = BB->begin(), IE = BB->end();
I != IE; ++I) {
// 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.isUnknown()) continue;
// Artificial lines such as calls to the global constructors.
if (Loc.getLine() == 0) continue;
if (Line == Loc.getLine()) continue;
Line = Loc.getLine();
if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;
GCOVLines &Lines = Block.getFile(SP.getFilename());
Lines.addLine(Loc.getLine());
}
}
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;
bool InsertIndCounterIncrCode = false;
for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
DICompileUnit CU(CU_Nodes->getOperand(i));
DIArray SPs = CU.getSubprograms();
SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
DISubprogram SP(SPs.getElement(i));
assert((!SP || SP.isSubprogram()) &&
"A MDNode in subprograms of a CU should be null or a DISubprogram.");
if (!SP)
continue;
Function *F = SP.getFunction();
if (!F) continue;
if (!functionHasLines(F)) continue;
if (!Result) Result = true;
unsigned Edges = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
if (isa<ReturnInst>(TI))
++Edges;
else
Edges += TI->getNumSuccessors();
}
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, (MDNode*)SP));
UniqueVector<BasicBlock *> ComplexEdgePreds;
UniqueVector<BasicBlock *> ComplexEdgeSuccs;
unsigned Edge = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
if (Successors) {
if (Successors == 1) {
IRBuilder<> Builder(BB->getFirstInsertionPt());
Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
Edge);
Value *Count = Builder.CreateLoad(Counter);
Count = Builder.CreateAdd(Count, Builder.getInt64(1));
Builder.CreateStore(Count, Counter);
} else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
IRBuilder<> Builder(BI);
Value *Sel = Builder.CreateSelect(BI->getCondition(),
Builder.getInt64(Edge),
Builder.getInt64(Edge + 1));
SmallVector<Value *, 2> Idx;
Idx.push_back(Builder.getInt64(0));
Idx.push_back(Sel);
Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
Value *Count = Builder.CreateLoad(Counter);
Count = Builder.CreateAdd(Count, Builder.getInt64(1));
Builder.CreateStore(Count, Counter);
} else {
ComplexEdgePreds.insert(BB);
for (int i = 0; i != Successors; ++i)
ComplexEdgeSuccs.insert(TI->getSuccessor(i));
}
Edge += Successors;
}
}
if (!ComplexEdgePreds.empty()) {
GlobalVariable *EdgeTable =
buildEdgeLookupTable(F, Counters,
ComplexEdgePreds, ComplexEdgeSuccs);
GlobalVariable *EdgeState = getEdgeStateValue();
for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
IRBuilder<> Builder(ComplexEdgePreds[i + 1]->getFirstInsertionPt());
Builder.CreateStore(Builder.getInt32(i), EdgeState);
}
for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
// Call runtime to perform increment.
IRBuilder<> Builder(ComplexEdgeSuccs[i+1]->getFirstInsertionPt());
Value *CounterPtrArray =
Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
i * ComplexEdgePreds.size());
// Build code to increment the counter.
InsertIndCounterIncrCode = true;
Builder.CreateCall2(getIncrementIndirectCounterFunc(),
EdgeState, CounterPtrArray);
}
}
}
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(true);
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.
Constant *GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
Builder.CreateCall2(GCOVInit, WriteoutF, FlushF);
Builder.CreateRetVoid();
appendToGlobalCtors(*M, F, 0);
}
if (InsertIndCounterIncrCode)
insertIndirectCounterIncrement();
return Result;
}
// All edges with successors that aren't branches are "complex", because it
// requires complex logic to pick which counter to update.
GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
Function *F,
GlobalVariable *Counters,
const UniqueVector<BasicBlock *> &Preds,
const UniqueVector<BasicBlock *> &Succs) {
// TODO: support invoke, threads. We rely on the fact that nothing can modify
// the whole-Module pred edge# between the time we set it and the time we next
// read it. Threads and invoke make this untrue.
// emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
size_t TableSize = Succs.size() * Preds.size();
Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
ArrayType *EdgeTableTy = ArrayType::get(Int64PtrTy, TableSize);
std::unique_ptr<Constant * []> EdgeTable(new Constant *[TableSize]);
Constant *NullValue = Constant::getNullValue(Int64PtrTy);
for (size_t i = 0; i != TableSize; ++i)
EdgeTable[i] = NullValue;
unsigned Edge = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
for (int i = 0; i != Successors; ++i) {
BasicBlock *Succ = TI->getSuccessor(i);
IRBuilder<> Builder(Succ);
Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
Edge + i);
EdgeTable[((Succs.idFor(Succ)-1) * Preds.size()) +
(Preds.idFor(BB)-1)] = cast<Constant>(Counter);
}
}
Edge += Successors;
}
ArrayRef<Constant*> V(&EdgeTable[0], TableSize);
GlobalVariable *EdgeTableGV =
new GlobalVariable(
*M, EdgeTableTy, true, GlobalValue::InternalLinkage,
ConstantArray::get(EdgeTableTy, V),
"__llvm_gcda_edge_table");
EdgeTableGV->setUnnamedAddr(true);
return EdgeTableGV;
}
Constant *GCOVProfiler::getStartFileFunc() {
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);
return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
}
Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
Type *Int32Ty = Type::getInt32Ty(*Ctx);
Type *Int64Ty = Type::getInt64Ty(*Ctx);
Type *Args[] = {
Int32Ty->getPointerTo(), // uint32_t *predecessor
Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
};
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
}
Constant *GCOVProfiler::getEmitFunctionFunc() {
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);
return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
}
Constant *GCOVProfiler::getEmitArcsFunc() {
Type *Args[] = {
Type::getInt32Ty(*Ctx), // uint32_t num_counters
Type::getInt64PtrTy(*Ctx), // uint64_t *counters
};
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
}
Constant *GCOVProfiler::getSummaryInfoFunc() {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
}
Constant *GCOVProfiler::getDeleteWriteoutFunctionListFunc() {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
return M->getOrInsertFunction("llvm_delete_writeout_function_list", FTy);
}
Constant *GCOVProfiler::getDeleteFlushFunctionListFunc() {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
return M->getOrInsertFunction("llvm_delete_flush_function_list", FTy);
}
Constant *GCOVProfiler::getEndFileFunc() {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
}
GlobalVariable *GCOVProfiler::getEdgeStateValue() {
GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
if (!GV) {
GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
GlobalValue::InternalLinkage,
ConstantInt::get(Type::getInt32Ty(*Ctx),
0xffffffff),
"__llvm_gcov_global_state_pred");
GV->setUnnamedAddr(true);
}
return GV;
}
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(true);
WriteoutF->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
WriteoutF->addFnAttr(Attribute::NoRedZone);
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
IRBuilder<> Builder(BB);
Constant *StartFile = getStartFileFunc();
Constant *EmitFunction = getEmitFunctionFunc();
Constant *EmitArcs = getEmitArcsFunc();
Constant *SummaryInfo = getSummaryInfoFunc();
Constant *EndFile = getEndFileFunc();
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (CU_Nodes) {
for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
DICompileUnit CU(CU_Nodes->getOperand(i));
std::string FilenameGcda = mangleName(CU, "gcda");
uint32_t CfgChecksum = FileChecksums.empty() ? 0 : FileChecksums[i];
Builder.CreateCall3(StartFile,
Builder.CreateGlobalStringPtr(FilenameGcda),
Builder.CreateGlobalStringPtr(ReversedVersion),
Builder.getInt32(CfgChecksum));
for (unsigned j = 0, e = CountersBySP.size(); j != e; ++j) {
DISubprogram SP(CountersBySP[j].second);
uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
Builder.CreateCall5(
EmitFunction, 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->getType()->getElementType())->getNumElements();
Builder.CreateCall2(EmitArcs,
Builder.getInt32(Arcs),
Builder.CreateConstGEP2_64(GV, 0, 0));
}
Builder.CreateCall(SummaryInfo);
Builder.CreateCall(EndFile);
}
}
Builder.CreateRetVoid();
return WriteoutF;
}
void GCOVProfiler::insertIndirectCounterIncrement() {
Function *Fn =
cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
Fn->setUnnamedAddr(true);
Fn->setLinkage(GlobalValue::InternalLinkage);
Fn->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
Fn->addFnAttr(Attribute::NoRedZone);
// Create basic blocks for function.
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
IRBuilder<> Builder(BB);
BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
// uint32_t pred = *predecessor;
// if (pred == 0xffffffff) return;
Argument *Arg = Fn->arg_begin();
Arg->setName("predecessor");
Value *Pred = Builder.CreateLoad(Arg, "pred");
Value *Cond = Builder.CreateICmpEQ(Pred, Builder.getInt32(0xffffffff));
BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
Builder.SetInsertPoint(PredNotNegOne);
// uint64_t *counter = counters[pred];
// if (!counter) return;
Value *ZExtPred = Builder.CreateZExt(Pred, Builder.getInt64Ty());
Arg = std::next(Fn->arg_begin());
Arg->setName("counters");
Value *GEP = Builder.CreateGEP(Arg, ZExtPred);
Value *Counter = Builder.CreateLoad(GEP, "counter");
Cond = Builder.CreateICmpEQ(Counter,
Constant::getNullValue(
Builder.getInt64Ty()->getPointerTo()));
Builder.CreateCondBr(Cond, Exit, CounterEnd);
// ++*counter;
Builder.SetInsertPoint(CounterEnd);
Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
Builder.getInt64(1));
Builder.CreateStore(Add, Counter);
Builder.CreateBr(Exit);
// Fill in the exit block.
Builder.SetInsertPoint(Exit);
Builder.CreateRetVoid();
}
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(true);
FlushF->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
FlushF->addFnAttr(Attribute::NoRedZone);
BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
// Write out the current counters.
Constant *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 (ArrayRef<std::pair<GlobalVariable *, MDNode *> >::iterator
I = CountersBySP.begin(), E = CountersBySP.end();
I != E; ++I) {
GlobalVariable *GV = I->first;
Constant *Null = Constant::getNullValue(GV->getType()->getElementType());
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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