Rename LineProfiling to GCOVProfiling to more accurately represent what it

does. Also mostly implement it. Still a work-in-progress, but generates legal
output on crafted test cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129630 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 621 insertions, 265 deletions

diff --git a/include/llvm/InitializePasses.h b/include/llvm/InitializePasses.h
index be71898af4..cca0194a60 100644
--- a/include/llvm/InitializePasses.h
+++ b/include/llvm/InitializePasses.h
@@ -94,7 +94,7 @@ void initializeDominatorTreePass(PassRegistry&);
 void initializeEdgeBundlesPass(PassRegistry&);
 void initializeEdgeProfilerPass(PassRegistry&);
 void initializePathProfilerPass(PassRegistry&);
-void initializeLineProfilerPass(PassRegistry&);
+void initializeGCOVProfilerPass(PassRegistry&);
 void initializeEarlyCSEPass(PassRegistry&);
 void initializeExpandISelPseudosPass(PassRegistry&);
 void initializeFindUsedTypesPass(PassRegistry&);
diff --git a/include/llvm/LinkAllPasses.h b/include/llvm/LinkAllPasses.h
index 9c486b0181..56c113b452 100644
--- a/include/llvm/LinkAllPasses.h
+++ b/include/llvm/LinkAllPasses.h
@@ -70,7 +70,7 @@ namespace {
       (void) llvm::createEdgeProfilerPass();
       (void) llvm::createOptimalEdgeProfilerPass();
       (void) llvm::createPathProfilerPass();
-      (void) llvm::createLineProfilerPass();
+      (void) llvm::createGCOVProfilerPass();
       (void) llvm::createFunctionInliningPass();
       (void) llvm::createAlwaysInlinerPass();
       (void) llvm::createGlobalDCEPass();
diff --git a/include/llvm/Transforms/Instrumentation.h b/include/llvm/Transforms/Instrumentation.h
index d47216dec7..3ef2f5a14d 100644
--- a/include/llvm/Transforms/Instrumentation.h
+++ b/include/llvm/Transforms/Instrumentation.h
@@ -27,8 +27,8 @@ ModulePass *createOptimalEdgeProfilerPass();
 // Insert path profiling instrumentation
 ModulePass *createPathProfilerPass();
 
-// Insert line profiling instrumentation
-ModulePass *createLineProfilerPass();
+// Insert GCOV profiling instrumentation
+ModulePass *createGCOVProfilerPass();
 
 } // End llvm namespace
 
diff --git a/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
new file mode 100644
index 0000000000..ec05872179
--- /dev/null
+++ b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -0,0 +1,508 @@
+//===- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "insert-gcov-profiling"
+
+#include "ProfilingUtils.h"
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Instructions.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/DebugLoc.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Support/PathV2.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/UniqueVector.h"
+#include <string>
+#include <utility>
+using namespace llvm;
+
+namespace {
+  class GCOVProfiler : public ModulePass {
+    bool runOnModule(Module &M);
+  public:
+    static char ID;
+    GCOVProfiler() : ModulePass(ID) {
+      initializeGCOVProfilerPass(*PassRegistry::getPassRegistry());
+    }
+    virtual const char *getPassName() const {
+      return "GCOV Profiler";
+    }
+
+  private:
+    // Create the GCNO files for the Module based on DebugInfo.
+    void EmitGCNO(DebugInfoFinder &DIF);
+
+    // Get pointers to the functions in the runtime library.
+    Constant *getStartFileFunc();
+    Constant *getEmitFunctionFunc();
+    Constant *getEmitArcsFunc();
+    Constant *getEndFileFunc();
+
+    // Add the function to write out all our counters to the global destructor
+    // list.
+    void InsertCounterWriteout(DebugInfoFinder &,
+                               SmallVector<std::pair<GlobalVariable *,
+                                                     uint32_t>, 8> &);
+
+    Module *Mod;
+    LLVMContext *Ctx;
+  };
+}
+
+char GCOVProfiler::ID = 0;
+INITIALIZE_PASS(GCOVProfiler, "insert-gcov-profiling",
+                "Insert instrumentation for GCOV profiling", false, false)
+
+ModulePass *llvm::createGCOVProfilerPass() { return new GCOVProfiler(); }
+
+static DISubprogram FindSubprogram(DIScope scope) {
+  while (!scope.isSubprogram()) {
+    assert(scope.isLexicalBlock() &&
+           "Debug location not lexical block or subprogram");
+    scope = DILexicalBlock(scope).getContext();
+  }
+  return DISubprogram(scope);
+}
+
+namespace {
+  class GCOVRecord {
+   protected:
+    static const char *lines_tag;
+    static const char *function_tag;
+    static const char *block_tag;
+    static const char *edge_tag;
+
+    GCOVRecord() {}
+
+    void WriteBytes(const char *b, int size) {
+      os->write(b, 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
+    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() + 5) / 4;
+    }
+
+    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)(5 - ((s.size() + 1) % 4)) > 0);
+      assert((unsigned)(5 - ((s.size() + 1) % 4)) <= 4);
+      WriteBytes("\0\0\0\0", 5 - ((s.size() + 1) % 4));
+    }
+
+    raw_ostream *os;
+  };
+  const char *GCOVRecord::lines_tag = "\0\0\x45\x01";
+  const char *GCOVRecord::function_tag = "\0\0\0\1";
+  const char *GCOVRecord::block_tag = "\0\0\x41\x01";
+  const char *GCOVRecord::edge_tag = "\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) {
+      lines.push_back(line);
+    }
+
+    uint32_t Length() {
+      return LengthOfGCOVString(filename) + 2 + lines.size();
+    }
+
+   private:
+    friend class GCOVBlock;
+
+    GCOVLines(std::string filename, raw_ostream *os)
+        : filename(filename) {
+      this->os = os;
+    }
+
+    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(std::string filename) {
+      GCOVLines *&lines = lines_by_file[filename];
+      if (!lines) {
+        lines = new GCOVLines(filename, os);
+      }
+      return *lines;
+    }
+
+    void AddEdge(GCOVBlock &successor) {
+      out_edges.push_back(&successor);
+    }
+
+    void WriteOut() {
+      uint32_t len = 3;
+      for (StringMap<GCOVLines *>::iterator I = lines_by_file.begin(),
+               E = lines_by_file.end(); I != E; ++I) {
+        len += I->second->Length();
+      }
+
+      WriteBytes(lines_tag, 4);
+      Write(len);
+      Write(number);
+      for (StringMap<GCOVLines *>::iterator I = lines_by_file.begin(),
+               E = lines_by_file.end(); I != E; ++I) {
+        Write(0);
+        WriteGCOVString(I->second->filename);
+        for (int i = 0, e = I->second->lines.size(); i != e; ++i) {
+          Write(I->second->lines[i]);
+        }
+      }
+      Write(0);
+      Write(0);
+    }
+
+    ~GCOVBlock() {
+      DeleteContainerSeconds(lines_by_file);
+    }
+
+   private:
+    friend class GCOVFunction;
+
+    GCOVBlock(uint32_t number, raw_ostream *os)
+        : number(number) {
+      this->os = os;
+    }
+
+    uint32_t number;
+    BasicBlock *block;
+    StringMap<GCOVLines *> lines_by_file;
+    SmallVector<GCOVBlock *, 4> out_edges;
+  };
+
+  // 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) {
+      this->os = os;
+
+      Function *F = SP.getFunction();
+      uint32_t i = 0;
+      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+        blocks[BB] = new GCOVBlock(i++, os);
+      }
+
+      WriteBytes(function_tag, 4);
+      uint32_t block_len = 1 + 1 + 1 + LengthOfGCOVString(SP.getName()) +
+          1 + LengthOfGCOVString(SP.getFilename()) + 1;
+      Write(block_len);
+      uint32_t ident = reinterpret_cast<intptr_t>((MDNode*)SP);
+      Write(ident);
+      Write(0); // checksum
+      WriteGCOVString(SP.getName());
+      WriteGCOVString(SP.getFilename());
+      Write(SP.getLineNumber());
+    }
+
+    ~GCOVFunction() {
+      DeleteContainerSeconds(blocks);
+    }
+
+    GCOVBlock &GetBlock(BasicBlock *BB) {
+      return *blocks[BB];
+    }
+
+    void WriteOut() {
+      // Emit count of blocks.
+      WriteBytes(block_tag, 4);
+      Write(blocks.size());
+      for (int i = 0, e = blocks.size(); i != e; ++i) {
+        Write(0);  // No flags on our blocks.
+      }
+
+      // Emit edges between blocks.
+      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = blocks.begin(),
+               E = blocks.end(); I != E; ++I) {
+        GCOVBlock &block = *I->second;
+        if (block.out_edges.empty()) continue;
+
+        WriteBytes(edge_tag, 4);
+        Write(block.out_edges.size() * 2 + 1);
+        Write(block.number);
+        for (int i = 0, e = block.out_edges.size(); i != e; ++i) {
+          Write(block.out_edges[i]->number);
+          Write(0);  // no flags
+        }
+      }
+
+      // Emit lines for each block.
+      for (DenseMap<BasicBlock *, GCOVBlock *>::iterator I = blocks.begin(),
+               E = blocks.end(); I != E; ++I) {
+        I->second->WriteOut();
+      }
+    }
+
+   private:
+    DenseMap<BasicBlock *, GCOVBlock *> blocks;
+  };
+}
+
+void GCOVProfiler::EmitGCNO(DebugInfoFinder &DIF) {
+  DenseMap<const MDNode *, raw_fd_ostream *> gcno_files;
+  for (DebugInfoFinder::iterator I = DIF.compile_unit_begin(),
+           E = DIF.compile_unit_end(); 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(*I);
+    raw_fd_ostream *&Out = gcno_files[CU];
+    std::string ErrorInfo;
+    Out = new raw_fd_ostream(
+        (sys::path::stem(CU.getFilename()) + ".gcno").str().c_str(),
+        ErrorInfo, raw_fd_ostream::F_Binary);
+    Out->write("oncg*404MVLL", 12);
+  }
+
+  for (DebugInfoFinder::iterator SPI = DIF.subprogram_begin(),
+           SPE = DIF.subprogram_end(); SPI != SPE; ++SPI) {
+    DISubprogram SP(*SPI);
+    raw_fd_ostream *&os = gcno_files[SP.getCompileUnit()];
+
+    GCOVFunction function(SP, os);
+    Function *F = SP.getFunction();
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+      GCOVBlock &block = function.GetBlock(BB);
+      TerminatorInst *TI = BB->getTerminator();
+      if (int successors = TI->getNumSuccessors()) {
+        for (int i = 0; i != successors; ++i) {
+          block.AddEdge(function.GetBlock(TI->getSuccessor(i)));
+        }
+      }
+
+      uint32_t line = 0;
+      for (BasicBlock::iterator I = BB->begin(), IE = BB->end(); I != IE; ++I) {
+        const DebugLoc &loc = I->getDebugLoc();
+        if (loc.isUnknown()) continue;
+        if (line == loc.getLine()) continue;
+        line = loc.getLine();
+        if (SP != FindSubprogram(DIScope(loc.getScope(*Ctx)))) continue;
+
+        GCOVLines &lines = block.GetFile(SP.getFilename());
+        lines.AddLine(loc.getLine());
+      }
+    }
+    function.WriteOut();
+  }
+
+  for (DenseMap<const MDNode *, raw_fd_ostream *>::iterator
+           I = gcno_files.begin(), E = gcno_files.end(); I != E; ++I) {
+    raw_fd_ostream *&Out = I->second;
+    Out->write("\0\0\0\0\0\0\0\0", 4); // EOF
+    Out->close();
+    delete Out;
+  }
+}
+
+bool GCOVProfiler::runOnModule(Module &M) {
+  Mod = &M;
+  Ctx = &M.getContext();
+
+  DebugInfoFinder DIF;
+  DIF.processModule(*Mod);
+
+  EmitGCNO(DIF);
+
+  SmallVector<std::pair<GlobalVariable *, uint32_t>, 8> counters_by_ident;
+  for (DebugInfoFinder::iterator SPI = DIF.subprogram_begin(),
+           SPE = DIF.subprogram_end(); SPI != SPE; ++SPI) {
+    DISubprogram SP(*SPI);
+    Function *F = SP.getFunction();
+
+    // TODO: GCOV format requires a distinct unified exit block.
+    unsigned edges = 0;
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+      TerminatorInst *TI = BB->getTerminator();
+      edges += TI->getNumSuccessors();
+    }
+
+    const ArrayType *counter_type =
+        ArrayType::get(Type::getInt64Ty(*Ctx), edges);
+    GlobalVariable *counter =
+        new GlobalVariable(*Mod, counter_type, false,
+                           GlobalValue::InternalLinkage,
+                           Constant::getNullValue(counter_type),
+                           "__llvm_gcov_ctr", 0, false, 0);
+    counters_by_ident.push_back(
+        std::make_pair(counter, reinterpret_cast<intptr_t>((MDNode*)SP)));
+
+    UniqueVector<BasicBlock *> complex_edge_preds;
+    UniqueVector<BasicBlock *> complex_edge_succs;
+
+    unsigned edge_num = 0;
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+      TerminatorInst *TI = BB->getTerminator();
+      if (int successors = TI->getNumSuccessors()) {
+        IRBuilder<> builder(TI);
+
+        if (successors == 1) {
+          Value *ctr = builder.CreateConstInBoundsGEP2_64(counter, 0, edge_num);
+          Value *count = builder.CreateLoad(ctr);
+          count = builder.CreateAdd(count,
+                                    ConstantInt::get(Type::getInt64Ty(*Ctx),1));
+          builder.CreateStore(count, ctr);
+        } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
+          Value *sel = builder.CreateSelect(
+              BI->getCondition(),
+              ConstantInt::get(Type::getInt64Ty(*Ctx), edge_num),
+              ConstantInt::get(Type::getInt64Ty(*Ctx), edge_num + 1));
+          SmallVector<Value *, 2> idx;
+          idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
+          idx.push_back(sel);
+          Value *ctr = builder.CreateInBoundsGEP(counter,
+                                                 idx.begin(), idx.end());
+          Value *count = builder.CreateLoad(ctr);
+          count = builder.CreateAdd(count,
+                                    ConstantInt::get(Type::getInt64Ty(*Ctx),1));
+          builder.CreateStore(count, ctr);
+        } else {
+          complex_edge_preds.insert(BB);
+          for (int i = 0; i != successors; ++i) {
+            complex_edge_succs.insert(TI->getSuccessor(i));
+          }
+        }
+        edge_num += successors;
+      }
+    }
+
+    // TODO: support switch, invoke, indirectbr
+    if (!complex_edge_preds.empty()) {
+      // emit a [preds x [succs x i64*]].
+      for (int i = 0, e = complex_edge_preds.size(); i != e; ++i) {
+        // call runtime to state save
+      }
+      for (int i = 0, e = complex_edge_succs.size(); i != e; ++i) {
+        // call runtime to perform increment
+      }
+    }
+  }
+
+  InsertCounterWriteout(DIF, counters_by_ident);
+
+  return true;
+}
+
+Constant *GCOVProfiler::getStartFileFunc() {
+  const Type *Args[1] = { Type::getInt8PtrTy(*Ctx) };
+  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
+                                              Args, false);
+  return Mod->getOrInsertFunction("llvm_gcda_start_file", FTy);
+}
+
+Constant *GCOVProfiler::getEmitFunctionFunc() {
+  const Type *Args[1] = { Type::getInt32Ty(*Ctx) };
+  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
+                                              Args, false);
+  return Mod->getOrInsertFunction("llvm_gcda_emit_function", FTy);
+}
+
+Constant *GCOVProfiler::getEmitArcsFunc() {
+  const Type *Args[] = {
+    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
+    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
+  };
+  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
+                                              Args, false);
+  return Mod->getOrInsertFunction("llvm_gcda_emit_arcs", FTy);
+}
+
+Constant *GCOVProfiler::getEndFileFunc() {
+  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
+  return Mod->getOrInsertFunction("llvm_gcda_end_file", FTy);
+}
+
+static std::string ReplaceStem(std::string orig_filename, std::string new_stem){
+  return (sys::path::stem(orig_filename) + "." + new_stem).str();
+}
+
+void GCOVProfiler::InsertCounterWriteout(
+    DebugInfoFinder &DIF,
+    SmallVector<std::pair<GlobalVariable *, uint32_t>, 8> &counters_by_ident) {
+
+  const FunctionType *WriteoutFTy =
+      FunctionType::get(Type::getVoidTy(*Ctx), false);
+  Function *WriteoutF = Function::Create(WriteoutFTy,
+                                         GlobalValue::InternalLinkage,
+                                         "__llvm_gcda_writeout", Mod);
+  WriteoutF->setUnnamedAddr(true);
+  BasicBlock *BB = BasicBlock::Create(*Ctx, "", WriteoutF);
+  IRBuilder<> builder(BB);
+
+  Constant *StartFile = getStartFileFunc();
+  Constant *EmitFunction = getEmitFunctionFunc();
+  Constant *EmitArcs = getEmitArcsFunc();
+  Constant *EndFile = getEndFileFunc();
+
+  for (DebugInfoFinder::iterator CUI = DIF.compile_unit_begin(),
+           CUE = DIF.compile_unit_end(); CUI != CUE; ++CUI) {
+    DICompileUnit compile_unit(*CUI);
+    std::string filename_gcda = ReplaceStem(compile_unit.getFilename(), "gcda");
+    builder.CreateCall(StartFile,
+                       builder.CreateGlobalStringPtr(filename_gcda));
+    for (SmallVector<std::pair<GlobalVariable *, uint32_t>, 8>::iterator
+             I = counters_by_ident.begin(), E = counters_by_ident.end();
+         I != E; ++I) {
+      builder.CreateCall(EmitFunction, ConstantInt::get(Type::getInt32Ty(*Ctx),
+                                                        I->second));
+      GlobalVariable *GV = I->first;
+      unsigned num_arcs =
+          cast<ArrayType>(GV->getType()->getElementType())->getNumElements();
+      builder.CreateCall2(
+          EmitArcs,
+          ConstantInt::get(Type::getInt32Ty(*Ctx), num_arcs),
+          builder.CreateConstGEP2_64(GV, 0, 0));
+    }
+    builder.CreateCall(EndFile);
+  }
+  builder.CreateRetVoid();
+
+  InsertProfilingShutdownCall(WriteoutF, Mod);
+}
diff --git a/lib/Transforms/Instrumentation/Instrumentation.cpp b/lib/Transforms/Instrumentation/Instrumentation.cpp
index b299bb71a4..71adc1ec6d 100644
--- a/lib/Transforms/Instrumentation/Instrumentation.cpp
+++ b/lib/Transforms/Instrumentation/Instrumentation.cpp
@@ -23,7 +23,7 @@ void llvm::initializeInstrumentation(PassRegistry &Registry) {
   initializeEdgeProfilerPass(Registry);
   initializeOptimalEdgeProfilerPass(Registry);
   initializePathProfilerPass(Registry);
-  initializeLineProfilerPass(Registry);
+  initializeGCOVProfilerPass(Registry);
 }
 
 /// LLVMInitializeInstrumentation - C binding for
diff --git a/lib/Transforms/Instrumentation/LineProfiling.cpp b/lib/Transforms/Instrumentation/LineProfiling.cpp
deleted file mode 100644
index 5628c3a811..0000000000
--- a/lib/Transforms/Instrumentation/LineProfiling.cpp
+++ /dev/null
@@ -1,217 +0,0 @@
-//===- LineProfiling.cpp - Insert counters for line profiling -------------===//
-//
-//                      The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass creates counters for the number of times that the original source
-// lines of code were executed.
-//
-// The lines are found from existing debug info in the LLVM IR. Iterating
-// through LLVM instructions, every time the debug location changes we insert a
-// new counter and instructions to increment the counter there. A global
-// destructor runs to dump the counters out to a file.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "insert-line-profiling"
-
-#include "ProfilingUtils.h"
-#include "llvm/Transforms/Instrumentation.h"
-#include "llvm/Analysis/DebugInfo.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/Instructions.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/DebugLoc.h"
-#include "llvm/Support/InstIterator.h"
-#include "llvm/Support/IRBuilder.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/StringExtras.h"
-#include <set>
-#include <string>
-using namespace llvm;
-
-STATISTIC(NumUpdatesInserted, "The # of counter increments inserted.");
-
-namespace {
-  class LineProfiler : public ModulePass {
-    bool runOnModule(Module &M);
-  public:
-    static char ID;
-    LineProfiler() : ModulePass(ID) {
-      initializeLineProfilerPass(*PassRegistry::getPassRegistry());
-    }
-    virtual const char *getPassName() const {
-      return "Line Profiler";
-    }
-
-  private:
-    // Get pointers to the functions in the runtime library.
-    Constant *getStartFileFunc();
-    Constant *getCounterFunc();
-    Constant *getEndFileFunc();
-
-    // Insert an increment of the counter before instruction I.
-    void InsertCounterUpdateBefore(Instruction *I);
-
-    // Add the function to write out all our counters to the global destructor
-    // list.
-    void InsertCounterWriteout();
-
-    // Mapping from the source location to the counter tracking that location.
-    DenseMap<DebugLoc, GlobalVariable *> counters;
-
-    Module *Mod;
-    LLVMContext *Ctx;
-  };
-}
-
-char LineProfiler::ID = 0;
-INITIALIZE_PASS(LineProfiler, "insert-line-profiling",
-                "Insert instrumentation for line profiling", false, false)
-
-ModulePass *llvm::createLineProfilerPass() { return new LineProfiler(); }
-
-bool LineProfiler::runOnModule(Module &M) {
-  Mod = &M;
-  Ctx = &M.getContext();
-
-  DebugLoc last_line;  // initializes to unknown
-  bool Changed = false;
-  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
-    for (inst_iterator II = inst_begin(F), IE = inst_end(F); II != IE; ++II) {
-      const DebugLoc &loc = II->getDebugLoc();
-      if (loc.isUnknown()) continue;
-      if (loc == last_line) continue;
-      last_line = loc;
-
-      InsertCounterUpdateBefore(&*II);
-      ++NumUpdatesInserted;
-      Changed = true;
-    }
-  }
-
-  if (Changed) {
-    InsertCounterWriteout();
-  }
-
-  return Changed;
-}
-
-void LineProfiler::InsertCounterUpdateBefore(Instruction *I) {
-  const DebugLoc &loc = I->getDebugLoc();
-  GlobalVariable *&counter = counters[loc];
-  const Type *Int64Ty = Type::getInt64Ty(*Ctx);
-  if (!counter) {
-    counter = new GlobalVariable(*Mod, Int64Ty, false,
-                                 GlobalValue::InternalLinkage,
-                                 Constant::getNullValue(Int64Ty),
-                                 "__llvm_prof_linecov_ctr", 0, false, 0);
-    counter->setVisibility(GlobalVariable::HiddenVisibility);
-    counter->setUnnamedAddr(true);
-  }
-
-  if (isa<PHINode>(I)) {
-    // We may not error out or crash in this case, because a module could put
-    // changing line numbers on phi nodes and still pass the verifier.
-    dbgs() << "Refusing to insert code before phi: " << *I << "\n";
-    I = I->getParent()->getFirstNonPHI();
-  }
-
-  IRBuilder<> builder(I);
-  Value *ctr = builder.CreateLoad(counter);
-  ctr = builder.CreateAdd(ctr, ConstantInt::get(Int64Ty, 1));
-  builder.CreateStore(ctr, counter);
-}
-
-static DISubprogram FindSubprogram(DIScope scope) {
-  while (!scope.isSubprogram()) {
-    assert(scope.isLexicalBlock() &&
-           "Debug location not lexical block or subprogram");
-    scope = DILexicalBlock(scope).getContext();
-  }
-  return DISubprogram(scope);
-}
-
-Constant *LineProfiler::getStartFileFunc() {
-  const Type *Args[1] = { Type::getInt8PtrTy(*Ctx) };
-  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
-                                              Args, false);
-  return Mod->getOrInsertFunction("llvm_prof_linectr_start_file", FTy);
-}
-
-Constant *LineProfiler::getCounterFunc() {
-  const Type *Args[] = {
-    Type::getInt8PtrTy(*Ctx),   // const char *dir
-    Type::getInt8PtrTy(*Ctx),   // const char *file
-    Type::getInt32Ty(*Ctx),     // uint32_t line
-    Type::getInt32Ty(*Ctx),     // uint32_t column
-    Type::getInt64PtrTy(*Ctx),  // int64_t *counter
-  };
-  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
-                                              Args, false);
-  return Mod->getOrInsertFunction("llvm_prof_linectr_emit_counter", FTy);
-}
-
-Constant *LineProfiler::getEndFileFunc() {
-  const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
-  return Mod->getOrInsertFunction("llvm_prof_linectr_end_file", FTy);
-}
-
-void LineProfiler::InsertCounterWriteout() {
-  std::set<std::string> compile_units;
-  for (DenseMap<DebugLoc, GlobalVariable *>::iterator I = counters.begin(),
-           E = counters.end(); I != E; ++I) {
-    const DebugLoc &loc = I->first;
-    DISubprogram subprogram(FindSubprogram(DIScope(loc.getScope(*Ctx))));
-    compile_units.insert(subprogram.getCompileUnit().getFilename().str());
-  }
-
-  const FunctionType *WriteoutFTy =
-      FunctionType::get(Type::getVoidTy(*Ctx), false);
-  Function *WriteoutF = Function::Create(WriteoutFTy,
-                                         GlobalValue::InternalLinkage,
-                                         "__llvm_prof_linecov_dtor",
-                                         Mod);
-  WriteoutF->setUnnamedAddr(true);
-  BasicBlock *BB = BasicBlock::Create(*Ctx, "", WriteoutF);
-  IRBuilder<> builder(BB);
-
-  Constant *StartFile = getStartFileFunc();
-  Constant *EmitCounter = getCounterFunc();
-  Constant *EndFile = getEndFileFunc();
-
-  for (std::set<std::string>::const_iterator CUI = compile_units.begin(),
-           CUE = compile_units.end(); CUI != CUE; ++CUI) {
-    builder.CreateCall(StartFile,
-                       builder.CreateGlobalStringPtr(*CUI));
-    for (DenseMap<DebugLoc, GlobalVariable *>::iterator I = counters.begin(),
-             E = counters.end(); I != E; ++I) {
-      const DebugLoc &loc = I->first;
-      DISubprogram subprogram(FindSubprogram(DIScope(loc.getScope(*Ctx))));
-      DICompileUnit compileunit(subprogram.getCompileUnit());
-
-      if (compileunit.getFilename() != *CUI)
-        continue;
-
-      Value *Args[] = {
-        builder.CreateGlobalStringPtr(subprogram.getDirectory()),
-        builder.CreateGlobalStringPtr(subprogram.getFilename()),
-        ConstantInt::get(Type::getInt32Ty(*Ctx), loc.getLine()),
-        ConstantInt::get(Type::getInt32Ty(*Ctx), loc.getCol()),
-        I->second
-      };
-      builder.CreateCall(EmitCounter, Args);
-    }
-    builder.CreateCall(EndFile);
-  }
-  builder.CreateRetVoid();
-
-  InsertProfilingShutdownCall(WriteoutF, Mod);
-}
diff --git a/runtime/libprofile/GCDAProfiling.c b/runtime/libprofile/GCDAProfiling.c
new file mode 100644
index 0000000000..ee48ab5b6b
--- /dev/null
+++ b/runtime/libprofile/GCDAProfiling.c
@@ -0,0 +1,104 @@
+/*===- GCDAProfiling.c - Support library for GCDA file emission -----------===*\
+|*
+|*                     The LLVM Compiler Infrastructure
+|*
+|* This file is distributed under the University of Illinois Open Source
+|* License. See LICENSE.TXT for details.
+|* 
+|*===----------------------------------------------------------------------===*|
+|* 
+|* This file implements the call back routines for the gcov profiling
+|* instrumentation pass. Link against this library when running code through
+|* the -insert-gcov-profiling LLVM pass.
+|*
+|* We emit files in a corrupt version of GCOV's "gcda" file format. These files
+|* are only close enough that LCOV will happily parse them. Anything that lcov
+|* ignores is missing.
+|*
+\*===----------------------------------------------------------------------===*/
+
+#include "llvm/Support/DataTypes.h"
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// #define DEBUG_GCDAPROFILING
+
+/*
+ * --- GCOV file format I/O primitives ---
+ */
+
+static FILE *output_file = NULL;
+
+static void write_int32(uint32_t i) {
+  fwrite(&i, 4, 1, output_file);
+}
+
+static void write_int64(uint64_t i) {
+  uint32_t lo, hi;
+  lo = i & 0x00000000ffffffff;
+  hi = i & 0xffffffff00000000;
+
+  write_int32(lo);
+  write_int32(hi);
+}
+
+/*
+ * --- LLVM line counter API ---
+ */
+
+/* A file in this case is a translation unit. Each .o file built with line
+ * profiling enabled will emit to a different file. Only one file may be
+ * started at a time.
+ */
+void llvm_gcda_start_file(const char *filename) {
+  output_file = fopen(filename, "w+");
+
+  /* gcda file, version 404*, stamp LLVM. */
+  fwrite("adcg*404MVLL", 12, 1, output_file);
+
+#ifdef DEBUG_GCDAPROFILING
+  printf("[%s]\n", filename);
+#endif
+}
+
+void llvm_gcda_emit_function(uint32_t ident) {
+#ifdef DEBUG_GCDAPROFILING
+  printf("function id=%x\n", ident);
+#endif
+
+  /* function tag */  
+  fwrite("\0\0\0\1", 4, 1, output_file);
+  write_int32(2);
+  write_int32(ident);
+  write_int32(0);
+}
+
+void llvm_gcda_emit_arcs(uint32_t num_counters, uint64_t *counters) {
+  uint32_t i;
+  /* counter #1 (arcs) tag */
+  fwrite("\0\0\xa1\1", 4, 1, output_file);
+  write_int32(num_counters * 2);
+  for (i = 0; i < num_counters; ++i) {
+    write_int64(counters[i]);
+  }
+
+#ifdef DEBUG_GCDAPROFILING
+  printf("  %u arcs\n", num_counters);
+  for (i = 0; i < num_counters; ++i) {
+    printf("  %llu\n", (unsigned long long)counters[i]);
+  }
+#endif
+}
+
+void llvm_gcda_end_file() {
+  /* Write out EOF record. */
+  fwrite("\0\0\0\0\0\0\0\0", 8, 1, output_file);
+  fclose(output_file);
+  output_file = NULL;
+
+#ifdef DEBUG_GCDAPROFILING
+  printf("-----\n");
+#endif
+}
diff --git a/runtime/libprofile/LineProfiling.c b/runtime/libprofile/LineProfiling.c
deleted file mode 100644
index 9db789ec0b..0000000000
--- a/runtime/libprofile/LineProfiling.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/*===- LineProfiling.c - Support library for line profiling ---------------===*\
-|*
-|*                     The LLVM Compiler Infrastructure
-|*
-|* This file is distributed under the University of Illinois Open Source
-|* License. See LICENSE.TXT for details.
-|* 
-|*===----------------------------------------------------------------------===*|
-|* 
-|* This file implements the call back routines for the line profiling
-|* instrumentation pass. Link against this library when running code through
-|* the -insert-line-profiling LLVM pass.
-|*
-\*===----------------------------------------------------------------------===*/
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <stdint.h>
-
-#include "llvm/Support/DataTypes.h"
-
-/* A file in this case is a translation unit. Each .o file built with line
- * profiling enabled will emit to a different file. Only one file may be
- * started at a time.
- */
-void llvm_prof_linectr_start_file(const char *orig_filename) {
-  printf("[%s]\n", orig_filename);
-}
-
-/* Emit data about a counter to the data file. */
-void llvm_prof_linectr_emit_counter(const char *dir, const char *file,
-                                    uint32_t line, uint32_t column,
-                                    uint64_t *counter) {
-  printf("%s/%s:%u:%u %llu\n", dir, file, line, column,
-         (unsigned long long)(*counter));
-}
-
-void llvm_prof_linectr_end_file() {
-  printf("-----\n");
-}
diff --git a/runtime/libprofile/libprofile.exports b/runtime/libprofile/libprofile.exports
index fb04ea3480..aca563fc5c 100644
--- a/runtime/libprofile/libprofile.exports
+++ b/runtime/libprofile/libprofile.exports
@@ -5,6 +5,7 @@ llvm_start_basic_block_tracing
 llvm_trace_basic_block
 llvm_increment_path_count
 llvm_decrement_path_count
-llvm_prof_linectr_start_file
-llvm_prof_linectr_emit_counter
-llvm_prof_linectr_end_file
+llvm_gcda_start_file
+llvm_gcda_emit_function
+llvm_gcda_emit_arcs
+llvm_gcda_end_file