1 //===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass implements GCOV-style profiling. When this pass is run it emits
11 // "gcno" files next to the existing source, and instruments the code that runs
12 // to records the edges between blocks that run and emit a complementary "gcda"
15 //===----------------------------------------------------------------------===//
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/Hashing.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/ADT/StringExtras.h"
22 #include "llvm/ADT/StringMap.h"
23 #include "llvm/ADT/UniqueVector.h"
24 #include "llvm/IR/DebugInfo.h"
25 #include "llvm/IR/DebugLoc.h"
26 #include "llvm/IR/IRBuilder.h"
27 #include "llvm/IR/InstIterator.h"
28 #include "llvm/IR/Instructions.h"
29 #include "llvm/IR/IntrinsicInst.h"
30 #include "llvm/IR/Module.h"
31 #include "llvm/Pass.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/FileSystem.h"
35 #include "llvm/Support/Path.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include "llvm/Transforms/GCOVProfiler.h"
38 #include "llvm/Transforms/Instrumentation.h"
39 #include "llvm/Transforms/Utils/ModuleUtils.h"
46 #define DEBUG_TYPE "insert-gcov-profiling"
48 static cl::opt<std::string>
49 DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
51 static cl::opt<bool> DefaultExitBlockBeforeBody("gcov-exit-block-before-body",
52 cl::init(false), cl::Hidden);
54 GCOVOptions GCOVOptions::getDefault() {
56 Options.EmitNotes = true;
57 Options.EmitData = true;
58 Options.UseCfgChecksum = false;
59 Options.NoRedZone = false;
60 Options.FunctionNamesInData = true;
61 Options.ExitBlockBeforeBody = DefaultExitBlockBeforeBody;
63 if (DefaultGCOVVersion.size() != 4) {
64 llvm::report_fatal_error(std::string("Invalid -default-gcov-version: ") +
67 memcpy(Options.Version, DefaultGCOVVersion.c_str(), 4);
76 GCOVProfiler() : GCOVProfiler(GCOVOptions::getDefault()) {}
77 GCOVProfiler(const GCOVOptions &Opts) : Options(Opts) {
78 assert((Options.EmitNotes || Options.EmitData) &&
79 "GCOVProfiler asked to do nothing?");
80 ReversedVersion[0] = Options.Version[3];
81 ReversedVersion[1] = Options.Version[2];
82 ReversedVersion[2] = Options.Version[1];
83 ReversedVersion[3] = Options.Version[0];
84 ReversedVersion[4] = '\0';
86 bool runOnModule(Module &M);
89 // Create the .gcno files for the Module based on DebugInfo.
90 void emitProfileNotes();
92 // Modify the program to track transitions along edges and call into the
93 // profiling runtime to emit .gcda files when run.
94 bool emitProfileArcs();
96 // Get pointers to the functions in the runtime library.
97 Constant *getStartFileFunc();
98 Constant *getIncrementIndirectCounterFunc();
99 Constant *getEmitFunctionFunc();
100 Constant *getEmitArcsFunc();
101 Constant *getSummaryInfoFunc();
102 Constant *getEndFileFunc();
104 // Create or retrieve an i32 state value that is used to represent the
105 // pred block number for certain non-trivial edges.
106 GlobalVariable *getEdgeStateValue();
108 // Produce a table of pointers to counters, by predecessor and successor
110 GlobalVariable *buildEdgeLookupTable(Function *F, GlobalVariable *Counter,
111 const UniqueVector<BasicBlock *> &Preds,
112 const UniqueVector<BasicBlock *> &Succs);
114 // Add the function to write out all our counters to the global destructor
117 insertCounterWriteout(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
118 Function *insertFlush(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
119 void insertIndirectCounterIncrement();
121 enum class GCovFileType { GCNO, GCDA };
122 std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
126 // Reversed, NUL-terminated copy of Options.Version.
127 char ReversedVersion[5];
128 // Checksum, produced by hash of EdgeDestinations
129 SmallVector<uint32_t, 4> FileChecksums;
133 SmallVector<std::unique_ptr<GCOVFunction>, 16> Funcs;
136 class GCOVProfilerLegacyPass : public ModulePass {
139 GCOVProfilerLegacyPass()
140 : GCOVProfilerLegacyPass(GCOVOptions::getDefault()) {}
141 GCOVProfilerLegacyPass(const GCOVOptions &Opts)
142 : ModulePass(ID), Profiler(Opts) {
143 initializeGCOVProfilerLegacyPassPass(*PassRegistry::getPassRegistry());
145 StringRef getPassName() const override { return "GCOV Profiler"; }
147 bool runOnModule(Module &M) override { return Profiler.runOnModule(M); }
150 GCOVProfiler Profiler;
154 char GCOVProfilerLegacyPass::ID = 0;
155 INITIALIZE_PASS(GCOVProfilerLegacyPass, "insert-gcov-profiling",
156 "Insert instrumentation for GCOV profiling", false, false)
158 ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
159 return new GCOVProfilerLegacyPass(Options);
162 static StringRef getFunctionName(const DISubprogram *SP) {
163 if (!SP->getLinkageName().empty())
164 return SP->getLinkageName();
165 return SP->getName();
171 static const char *const LinesTag;
172 static const char *const FunctionTag;
173 static const char *const BlockTag;
174 static const char *const EdgeTag;
176 GCOVRecord() = default;
178 void writeBytes(const char *Bytes, int Size) {
179 os->write(Bytes, Size);
182 void write(uint32_t i) {
183 writeBytes(reinterpret_cast<char*>(&i), 4);
186 // Returns the length measured in 4-byte blocks that will be used to
187 // represent this string in a GCOV file
188 static unsigned lengthOfGCOVString(StringRef s) {
189 // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
190 // padding out to the next 4-byte word. The length is measured in 4-byte
191 // words including padding, not bytes of actual string.
192 return (s.size() / 4) + 1;
195 void writeGCOVString(StringRef s) {
196 uint32_t Len = lengthOfGCOVString(s);
198 writeBytes(s.data(), s.size());
200 // Write 1 to 4 bytes of NUL padding.
201 assert((unsigned)(4 - (s.size() % 4)) > 0);
202 assert((unsigned)(4 - (s.size() % 4)) <= 4);
203 writeBytes("\0\0\0\0", 4 - (s.size() % 4));
208 const char *const GCOVRecord::LinesTag = "\0\0\x45\x01";
209 const char *const GCOVRecord::FunctionTag = "\0\0\0\1";
210 const char *const GCOVRecord::BlockTag = "\0\0\x41\x01";
211 const char *const GCOVRecord::EdgeTag = "\0\0\x43\x01";
216 // Constructed only by requesting it from a GCOVBlock, this object stores a
217 // list of line numbers and a single filename, representing lines that belong
219 class GCOVLines : public GCOVRecord {
221 void addLine(uint32_t Line) {
222 assert(Line != 0 && "Line zero is not a valid real line number.");
223 Lines.push_back(Line);
226 uint32_t length() const {
227 // Here 2 = 1 for string length + 1 for '0' id#.
228 return lengthOfGCOVString(Filename) + 2 + Lines.size();
233 writeGCOVString(Filename);
234 for (int i = 0, e = Lines.size(); i != e; ++i)
238 GCOVLines(StringRef F, raw_ostream *os)
245 SmallVector<uint32_t, 32> Lines;
249 // Represent a basic block in GCOV. Each block has a unique number in the
250 // function, number of lines belonging to each block, and a set of edges to
252 class GCOVBlock : public GCOVRecord {
254 GCOVLines &getFile(StringRef Filename) {
255 return LinesByFile.try_emplace(Filename, Filename, os).first->second;
258 void addEdge(GCOVBlock &Successor) {
259 OutEdges.push_back(&Successor);
264 SmallVector<StringMapEntry<GCOVLines> *, 32> SortedLinesByFile;
265 for (auto &I : LinesByFile) {
266 Len += I.second.length();
267 SortedLinesByFile.push_back(&I);
270 writeBytes(LinesTag, 4);
275 SortedLinesByFile.begin(), SortedLinesByFile.end(),
276 [](StringMapEntry<GCOVLines> *LHS, StringMapEntry<GCOVLines> *RHS) {
277 return LHS->getKey() < RHS->getKey();
279 for (auto &I : SortedLinesByFile)
280 I->getValue().writeOut();
285 GCOVBlock(const GCOVBlock &RHS) : GCOVRecord(RHS), Number(RHS.Number) {
286 // Only allow copy before edges and lines have been added. After that,
287 // there are inter-block pointers (eg: edges) that won't take kindly to
288 // blocks being copied or moved around.
289 assert(LinesByFile.empty());
290 assert(OutEdges.empty());
294 friend class GCOVFunction;
296 GCOVBlock(uint32_t Number, raw_ostream *os)
302 StringMap<GCOVLines> LinesByFile;
303 SmallVector<GCOVBlock *, 4> OutEdges;
306 // A function has a unique identifier, a checksum (we leave as zero) and a
307 // set of blocks and a map of edges between blocks. This is the only GCOV
308 // object users can construct, the blocks and lines will be rooted here.
309 class GCOVFunction : public GCOVRecord {
311 GCOVFunction(const DISubprogram *SP, Function *F, raw_ostream *os,
312 uint32_t Ident, bool UseCfgChecksum, bool ExitBlockBeforeBody)
313 : SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0),
317 DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
320 for (auto &BB : *F) {
321 // Skip index 1 if it's assigned to the ReturnBlock.
322 if (i == 1 && ExitBlockBeforeBody)
324 Blocks.insert(std::make_pair(&BB, GCOVBlock(i++, os)));
326 if (!ExitBlockBeforeBody)
327 ReturnBlock.Number = i;
329 std::string FunctionNameAndLine;
330 raw_string_ostream FNLOS(FunctionNameAndLine);
331 FNLOS << getFunctionName(SP) << SP->getLine();
333 FuncChecksum = hash_value(FunctionNameAndLine);
336 GCOVBlock &getBlock(BasicBlock *BB) {
337 return Blocks.find(BB)->second;
340 GCOVBlock &getReturnBlock() {
344 std::string getEdgeDestinations() {
345 std::string EdgeDestinations;
346 raw_string_ostream EDOS(EdgeDestinations);
347 Function *F = Blocks.begin()->first->getParent();
348 for (BasicBlock &I : *F) {
349 GCOVBlock &Block = getBlock(&I);
350 for (int i = 0, e = Block.OutEdges.size(); i != e; ++i)
351 EDOS << Block.OutEdges[i]->Number;
353 return EdgeDestinations;
356 uint32_t getFuncChecksum() {
360 void setCfgChecksum(uint32_t Checksum) {
361 CfgChecksum = Checksum;
365 writeBytes(FunctionTag, 4);
366 uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
367 1 + lengthOfGCOVString(SP->getFilename()) + 1;
375 writeGCOVString(getFunctionName(SP));
376 writeGCOVString(SP->getFilename());
377 write(SP->getLine());
379 // Emit count of blocks.
380 writeBytes(BlockTag, 4);
381 write(Blocks.size() + 1);
382 for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
383 write(0); // No flags on our blocks.
385 DEBUG(dbgs() << Blocks.size() << " blocks.\n");
387 // Emit edges between blocks.
388 if (Blocks.empty()) return;
389 Function *F = Blocks.begin()->first->getParent();
390 for (BasicBlock &I : *F) {
391 GCOVBlock &Block = getBlock(&I);
392 if (Block.OutEdges.empty()) continue;
394 writeBytes(EdgeTag, 4);
395 write(Block.OutEdges.size() * 2 + 1);
397 for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
398 DEBUG(dbgs() << Block.Number << " -> " << Block.OutEdges[i]->Number
400 write(Block.OutEdges[i]->Number);
401 write(0); // no flags
405 // Emit lines for each block.
406 for (BasicBlock &I : *F)
407 getBlock(&I).writeOut();
411 const DISubprogram *SP;
413 uint32_t FuncChecksum;
415 uint32_t CfgChecksum;
416 DenseMap<BasicBlock *, GCOVBlock> Blocks;
417 GCOVBlock ReturnBlock;
421 std::string GCOVProfiler::mangleName(const DICompileUnit *CU,
422 GCovFileType OutputType) {
423 bool Notes = OutputType == GCovFileType::GCNO;
425 if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
426 for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
427 MDNode *N = GCov->getOperand(i);
428 bool ThreeElement = N->getNumOperands() == 3;
429 if (!ThreeElement && N->getNumOperands() != 2)
431 if (dyn_cast<MDNode>(N->getOperand(ThreeElement ? 2 : 1)) != CU)
435 // These nodes have no mangling to apply, it's stored mangled in the
437 MDString *NotesFile = dyn_cast<MDString>(N->getOperand(0));
438 MDString *DataFile = dyn_cast<MDString>(N->getOperand(1));
439 if (!NotesFile || !DataFile)
441 return Notes ? NotesFile->getString() : DataFile->getString();
444 MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
448 SmallString<128> Filename = GCovFile->getString();
449 sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
450 return Filename.str();
454 SmallString<128> Filename = CU->getFilename();
455 sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
456 StringRef FName = sys::path::filename(Filename);
457 SmallString<128> CurPath;
458 if (sys::fs::current_path(CurPath)) return FName;
459 sys::path::append(CurPath, FName);
460 return CurPath.str();
463 bool GCOVProfiler::runOnModule(Module &M) {
465 Ctx = &M.getContext();
467 if (Options.EmitNotes) emitProfileNotes();
468 if (Options.EmitData) return emitProfileArcs();
472 PreservedAnalyses GCOVProfilerPass::run(Module &M,
473 ModuleAnalysisManager &AM) {
475 GCOVProfiler Profiler(GCOVOpts);
477 if (!Profiler.runOnModule(M))
478 return PreservedAnalyses::all();
480 return PreservedAnalyses::none();
483 static bool functionHasLines(Function &F) {
484 // Check whether this function actually has any source lines. Not only
485 // do these waste space, they also can crash gcov.
488 // Debug intrinsic locations correspond to the location of the
489 // declaration, not necessarily any statements or expressions.
490 if (isa<DbgInfoIntrinsic>(&I)) continue;
492 const DebugLoc &Loc = I.getDebugLoc();
496 // Artificial lines such as calls to the global constructors.
497 if (Loc.getLine() == 0) continue;
505 void GCOVProfiler::emitProfileNotes() {
506 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
507 if (!CU_Nodes) return;
509 for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
510 // Each compile unit gets its own .gcno file. This means that whether we run
511 // this pass over the original .o's as they're produced, or run it after
512 // LTO, we'll generate the same .gcno files.
514 auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
516 // Skip module skeleton (and module) CUs.
521 raw_fd_ostream out(mangleName(CU, GCovFileType::GCNO), EC, sys::fs::F_None);
522 std::string EdgeDestinations;
524 unsigned FunctionIdent = 0;
525 for (auto &F : M->functions()) {
526 DISubprogram *SP = F.getSubprogram();
528 if (!functionHasLines(F)) continue;
530 // gcov expects every function to start with an entry block that has a
531 // single successor, so split the entry block to make sure of that.
532 BasicBlock &EntryBlock = F.getEntryBlock();
533 BasicBlock::iterator It = EntryBlock.begin();
534 while (isa<AllocaInst>(*It) || isa<DbgInfoIntrinsic>(*It))
536 EntryBlock.splitBasicBlock(It);
538 Funcs.push_back(make_unique<GCOVFunction>(SP, &F, &out, FunctionIdent++,
539 Options.UseCfgChecksum,
540 Options.ExitBlockBeforeBody));
541 GCOVFunction &Func = *Funcs.back();
544 GCOVBlock &Block = Func.getBlock(&BB);
545 TerminatorInst *TI = BB.getTerminator();
546 if (int successors = TI->getNumSuccessors()) {
547 for (int i = 0; i != successors; ++i) {
548 Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
550 } else if (isa<ReturnInst>(TI)) {
551 Block.addEdge(Func.getReturnBlock());
556 // Debug intrinsic locations correspond to the location of the
557 // declaration, not necessarily any statements or expressions.
558 if (isa<DbgInfoIntrinsic>(&I)) continue;
560 const DebugLoc &Loc = I.getDebugLoc();
564 // Artificial lines such as calls to the global constructors.
565 if (Loc.getLine() == 0) continue;
567 if (Line == Loc.getLine()) continue;
568 Line = Loc.getLine();
569 if (SP != getDISubprogram(Loc.getScope()))
572 GCOVLines &Lines = Block.getFile(SP->getFilename());
573 Lines.addLine(Loc.getLine());
576 EdgeDestinations += Func.getEdgeDestinations();
579 FileChecksums.push_back(hash_value(EdgeDestinations));
580 out.write("oncg", 4);
581 out.write(ReversedVersion, 4);
582 out.write(reinterpret_cast<char*>(&FileChecksums.back()), 4);
584 for (auto &Func : Funcs) {
585 Func->setCfgChecksum(FileChecksums.back());
589 out.write("\0\0\0\0\0\0\0\0", 8); // EOF
594 bool GCOVProfiler::emitProfileArcs() {
595 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
596 if (!CU_Nodes) return false;
599 bool InsertIndCounterIncrCode = false;
600 for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
601 SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
602 for (auto &F : M->functions()) {
603 DISubprogram *SP = F.getSubprogram();
605 if (!functionHasLines(F)) continue;
606 if (!Result) Result = true;
609 TerminatorInst *TI = BB.getTerminator();
610 if (isa<ReturnInst>(TI))
613 Edges += TI->getNumSuccessors();
616 ArrayType *CounterTy =
617 ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
618 GlobalVariable *Counters =
619 new GlobalVariable(*M, CounterTy, false,
620 GlobalValue::InternalLinkage,
621 Constant::getNullValue(CounterTy),
623 CountersBySP.push_back(std::make_pair(Counters, SP));
625 UniqueVector<BasicBlock *> ComplexEdgePreds;
626 UniqueVector<BasicBlock *> ComplexEdgeSuccs;
630 TerminatorInst *TI = BB.getTerminator();
631 int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
633 if (Successors == 1) {
634 IRBuilder<> Builder(&*BB.getFirstInsertionPt());
635 Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
637 Value *Count = Builder.CreateLoad(Counter);
638 Count = Builder.CreateAdd(Count, Builder.getInt64(1));
639 Builder.CreateStore(Count, Counter);
640 } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
641 IRBuilder<> Builder(BI);
642 Value *Sel = Builder.CreateSelect(BI->getCondition(),
643 Builder.getInt64(Edge),
644 Builder.getInt64(Edge + 1));
645 Value *Counter = Builder.CreateInBoundsGEP(
646 Counters->getValueType(), Counters, {Builder.getInt64(0), Sel});
647 Value *Count = Builder.CreateLoad(Counter);
648 Count = Builder.CreateAdd(Count, Builder.getInt64(1));
649 Builder.CreateStore(Count, Counter);
651 ComplexEdgePreds.insert(&BB);
652 for (int i = 0; i != Successors; ++i)
653 ComplexEdgeSuccs.insert(TI->getSuccessor(i));
660 if (!ComplexEdgePreds.empty()) {
661 GlobalVariable *EdgeTable =
662 buildEdgeLookupTable(&F, Counters,
663 ComplexEdgePreds, ComplexEdgeSuccs);
664 GlobalVariable *EdgeState = getEdgeStateValue();
666 for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
667 IRBuilder<> Builder(&*ComplexEdgePreds[i + 1]->getFirstInsertionPt());
668 Builder.CreateStore(Builder.getInt32(i), EdgeState);
671 for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
672 // Call runtime to perform increment.
673 IRBuilder<> Builder(&*ComplexEdgeSuccs[i + 1]->getFirstInsertionPt());
674 Value *CounterPtrArray =
675 Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
676 i * ComplexEdgePreds.size());
678 // Build code to increment the counter.
679 InsertIndCounterIncrCode = true;
680 Builder.CreateCall(getIncrementIndirectCounterFunc(),
681 {EdgeState, CounterPtrArray});
686 Function *WriteoutF = insertCounterWriteout(CountersBySP);
687 Function *FlushF = insertFlush(CountersBySP);
689 // Create a small bit of code that registers the "__llvm_gcov_writeout" to
690 // be executed at exit and the "__llvm_gcov_flush" function to be executed
691 // when "__gcov_flush" is called.
692 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
693 Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
694 "__llvm_gcov_init", M);
695 F->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
696 F->setLinkage(GlobalValue::InternalLinkage);
697 F->addFnAttr(Attribute::NoInline);
698 if (Options.NoRedZone)
699 F->addFnAttr(Attribute::NoRedZone);
701 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
702 IRBuilder<> Builder(BB);
704 FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
706 PointerType::get(FTy, 0),
707 PointerType::get(FTy, 0)
709 FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
711 // Initialize the environment and register the local writeout and flush
713 Constant *GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
714 Builder.CreateCall(GCOVInit, {WriteoutF, FlushF});
715 Builder.CreateRetVoid();
717 appendToGlobalCtors(*M, F, 0);
720 if (InsertIndCounterIncrCode)
721 insertIndirectCounterIncrement();
726 // All edges with successors that aren't branches are "complex", because it
727 // requires complex logic to pick which counter to update.
728 GlobalVariable *GCOVProfiler::buildEdgeLookupTable(
730 GlobalVariable *Counters,
731 const UniqueVector<BasicBlock *> &Preds,
732 const UniqueVector<BasicBlock *> &Succs) {
733 // TODO: support invoke, threads. We rely on the fact that nothing can modify
734 // the whole-Module pred edge# between the time we set it and the time we next
735 // read it. Threads and invoke make this untrue.
737 // emit [(succs * preds) x i64*], logically [succ x [pred x i64*]].
738 size_t TableSize = Succs.size() * Preds.size();
739 Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
740 ArrayType *EdgeTableTy = ArrayType::get(Int64PtrTy, TableSize);
742 std::unique_ptr<Constant * []> EdgeTable(new Constant *[TableSize]);
743 Constant *NullValue = Constant::getNullValue(Int64PtrTy);
744 for (size_t i = 0; i != TableSize; ++i)
745 EdgeTable[i] = NullValue;
748 for (BasicBlock &BB : *F) {
749 TerminatorInst *TI = BB.getTerminator();
750 int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
751 if (Successors > 1 && !isa<BranchInst>(TI) && !isa<ReturnInst>(TI)) {
752 for (int i = 0; i != Successors; ++i) {
753 BasicBlock *Succ = TI->getSuccessor(i);
754 IRBuilder<> Builder(Succ);
755 Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
757 EdgeTable[((Succs.idFor(Succ) - 1) * Preds.size()) +
758 (Preds.idFor(&BB) - 1)] = cast<Constant>(Counter);
764 GlobalVariable *EdgeTableGV =
766 *M, EdgeTableTy, true, GlobalValue::InternalLinkage,
767 ConstantArray::get(EdgeTableTy,
768 makeArrayRef(&EdgeTable[0],TableSize)),
769 "__llvm_gcda_edge_table");
770 EdgeTableGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
774 Constant *GCOVProfiler::getStartFileFunc() {
776 Type::getInt8PtrTy(*Ctx), // const char *orig_filename
777 Type::getInt8PtrTy(*Ctx), // const char version[4]
778 Type::getInt32Ty(*Ctx), // uint32_t checksum
780 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
781 return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
784 Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
785 Type *Int32Ty = Type::getInt32Ty(*Ctx);
786 Type *Int64Ty = Type::getInt64Ty(*Ctx);
788 Int32Ty->getPointerTo(), // uint32_t *predecessor
789 Int64Ty->getPointerTo()->getPointerTo() // uint64_t **counters
791 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
792 return M->getOrInsertFunction("__llvm_gcov_indirect_counter_increment", FTy);
795 Constant *GCOVProfiler::getEmitFunctionFunc() {
797 Type::getInt32Ty(*Ctx), // uint32_t ident
798 Type::getInt8PtrTy(*Ctx), // const char *function_name
799 Type::getInt32Ty(*Ctx), // uint32_t func_checksum
800 Type::getInt8Ty(*Ctx), // uint8_t use_extra_checksum
801 Type::getInt32Ty(*Ctx), // uint32_t cfg_checksum
803 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
804 return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
807 Constant *GCOVProfiler::getEmitArcsFunc() {
809 Type::getInt32Ty(*Ctx), // uint32_t num_counters
810 Type::getInt64PtrTy(*Ctx), // uint64_t *counters
812 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
813 return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
816 Constant *GCOVProfiler::getSummaryInfoFunc() {
817 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
818 return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
821 Constant *GCOVProfiler::getEndFileFunc() {
822 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
823 return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
826 GlobalVariable *GCOVProfiler::getEdgeStateValue() {
827 GlobalVariable *GV = M->getGlobalVariable("__llvm_gcov_global_state_pred");
829 GV = new GlobalVariable(*M, Type::getInt32Ty(*Ctx), false,
830 GlobalValue::InternalLinkage,
831 ConstantInt::get(Type::getInt32Ty(*Ctx),
833 "__llvm_gcov_global_state_pred");
834 GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
839 Function *GCOVProfiler::insertCounterWriteout(
840 ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
841 FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
842 Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
844 WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
845 "__llvm_gcov_writeout", M);
846 WriteoutF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
847 WriteoutF->addFnAttr(Attribute::NoInline);
848 if (Options.NoRedZone)
849 WriteoutF->addFnAttr(Attribute::NoRedZone);
851 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
852 IRBuilder<> Builder(BB);
854 Constant *StartFile = getStartFileFunc();
855 Constant *EmitFunction = getEmitFunctionFunc();
856 Constant *EmitArcs = getEmitArcsFunc();
857 Constant *SummaryInfo = getSummaryInfoFunc();
858 Constant *EndFile = getEndFileFunc();
860 NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
862 for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
863 auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
865 // Skip module skeleton (and module) CUs.
869 std::string FilenameGcda = mangleName(CU, GCovFileType::GCDA);
870 uint32_t CfgChecksum = FileChecksums.empty() ? 0 : FileChecksums[i];
871 Builder.CreateCall(StartFile,
872 {Builder.CreateGlobalStringPtr(FilenameGcda),
873 Builder.CreateGlobalStringPtr(ReversedVersion),
874 Builder.getInt32(CfgChecksum)});
875 for (unsigned j = 0, e = CountersBySP.size(); j != e; ++j) {
876 auto *SP = cast_or_null<DISubprogram>(CountersBySP[j].second);
877 uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
880 {Builder.getInt32(j),
881 Options.FunctionNamesInData
882 ? Builder.CreateGlobalStringPtr(getFunctionName(SP))
883 : Constant::getNullValue(Builder.getInt8PtrTy()),
884 Builder.getInt32(FuncChecksum),
885 Builder.getInt8(Options.UseCfgChecksum),
886 Builder.getInt32(CfgChecksum)});
888 GlobalVariable *GV = CountersBySP[j].first;
890 cast<ArrayType>(GV->getValueType())->getNumElements();
891 Builder.CreateCall(EmitArcs, {Builder.getInt32(Arcs),
892 Builder.CreateConstGEP2_64(GV, 0, 0)});
894 Builder.CreateCall(SummaryInfo, {});
895 Builder.CreateCall(EndFile, {});
899 Builder.CreateRetVoid();
903 void GCOVProfiler::insertIndirectCounterIncrement() {
905 cast<Function>(GCOVProfiler::getIncrementIndirectCounterFunc());
906 Fn->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
907 Fn->setLinkage(GlobalValue::InternalLinkage);
908 Fn->addFnAttr(Attribute::NoInline);
909 if (Options.NoRedZone)
910 Fn->addFnAttr(Attribute::NoRedZone);
912 // Create basic blocks for function.
913 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", Fn);
914 IRBuilder<> Builder(BB);
916 BasicBlock *PredNotNegOne = BasicBlock::Create(*Ctx, "", Fn);
917 BasicBlock *CounterEnd = BasicBlock::Create(*Ctx, "", Fn);
918 BasicBlock *Exit = BasicBlock::Create(*Ctx, "exit", Fn);
920 // uint32_t pred = *predecessor;
921 // if (pred == 0xffffffff) return;
922 Argument *Arg = &*Fn->arg_begin();
923 Arg->setName("predecessor");
924 Value *Pred = Builder.CreateLoad(Arg, "pred");
925 Value *Cond = Builder.CreateICmpEQ(Pred, Builder.getInt32(0xffffffff));
926 BranchInst::Create(Exit, PredNotNegOne, Cond, BB);
928 Builder.SetInsertPoint(PredNotNegOne);
930 // uint64_t *counter = counters[pred];
931 // if (!counter) return;
932 Value *ZExtPred = Builder.CreateZExt(Pred, Builder.getInt64Ty());
933 Arg = &*std::next(Fn->arg_begin());
934 Arg->setName("counters");
935 Value *GEP = Builder.CreateGEP(Type::getInt64PtrTy(*Ctx), Arg, ZExtPred);
936 Value *Counter = Builder.CreateLoad(GEP, "counter");
937 Cond = Builder.CreateICmpEQ(Counter,
938 Constant::getNullValue(
939 Builder.getInt64Ty()->getPointerTo()));
940 Builder.CreateCondBr(Cond, Exit, CounterEnd);
943 Builder.SetInsertPoint(CounterEnd);
944 Value *Add = Builder.CreateAdd(Builder.CreateLoad(Counter),
945 Builder.getInt64(1));
946 Builder.CreateStore(Add, Counter);
947 Builder.CreateBr(Exit);
949 // Fill in the exit block.
950 Builder.SetInsertPoint(Exit);
951 Builder.CreateRetVoid();
954 Function *GCOVProfiler::
955 insertFlush(ArrayRef<std::pair<GlobalVariable*, MDNode*> > CountersBySP) {
956 FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
957 Function *FlushF = M->getFunction("__llvm_gcov_flush");
959 FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
960 "__llvm_gcov_flush", M);
962 FlushF->setLinkage(GlobalValue::InternalLinkage);
963 FlushF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
964 FlushF->addFnAttr(Attribute::NoInline);
965 if (Options.NoRedZone)
966 FlushF->addFnAttr(Attribute::NoRedZone);
968 BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
970 // Write out the current counters.
971 Constant *WriteoutF = M->getFunction("__llvm_gcov_writeout");
972 assert(WriteoutF && "Need to create the writeout function first!");
974 IRBuilder<> Builder(Entry);
975 Builder.CreateCall(WriteoutF, {});
977 // Zero out the counters.
978 for (const auto &I : CountersBySP) {
979 GlobalVariable *GV = I.first;
980 Constant *Null = Constant::getNullValue(GV->getValueType());
981 Builder.CreateStore(Null, GV);
984 Type *RetTy = FlushF->getReturnType();
985 if (RetTy == Type::getVoidTy(*Ctx))
986 Builder.CreateRetVoid();
987 else if (RetTy->isIntegerTy())
988 // Used if __llvm_gcov_flush was implicitly declared.
989 Builder.CreateRet(ConstantInt::get(RetTy, 0));
991 report_fatal_error("invalid return type for __llvm_gcov_flush");