1 //===- TraceBasicBlocks.cpp - Insert basic-block trace instrumentation ----===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass instruments the specified program with calls into a runtime
11 // library that cause it to output a trace of basic blocks as a side effect
12 // of normal execution.
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Module.h"
19 #include "llvm/Pass.h"
20 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
21 #include "llvm/Transforms/Instrumentation.h"
22 #include "llvm/Instructions.h"
23 #include "ProfilingUtils.h"
24 #include "llvm/Support/Debug.h"
29 class TraceBasicBlocks : public ModulePass {
30 bool runOnModule(Module &M);
33 RegisterOpt<TraceBasicBlocks> X("trace-basic-blocks",
34 "Insert instrumentation for basic block tracing");
37 ModulePass *llvm::createTraceBasicBlockPass()
39 return new TraceBasicBlocks();
42 static void InsertInstrumentationCall (BasicBlock *BB,
43 const std::string FnName,
45 DEBUG (std::cerr << "InsertInstrumentationCall (\"" << BB->getName ()
46 << "\", \"" << FnName << "\", " << BBNumber << ")\n");
47 Module &M = *BB->getParent ()->getParent ();
48 Function *InstrFn = M.getOrInsertFunction (FnName, Type::VoidTy,
50 std::vector<Value*> Args (1);
51 Args[0] = ConstantUInt::get (Type::UIntTy, BBNumber);
53 // Insert the call after any alloca or PHI instructions...
54 BasicBlock::iterator InsertPos = BB->begin();
55 while (isa<AllocaInst>(InsertPos) || isa<PHINode>(InsertPos))
58 Instruction *InstrCall = new CallInst (InstrFn, Args, "", InsertPos);
61 bool TraceBasicBlocks::runOnModule(Module &M) {
62 Function *Main = M.getMainFunction();
64 std::cerr << "WARNING: cannot insert basic-block trace instrumentation"
65 << " into a module with no main function!\n";
66 return false; // No main, no instrumentation!
69 unsigned BBNumber = 0;
70 for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
71 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
72 InsertInstrumentationCall (BB, "llvm_trace_basic_block", BBNumber);
76 // Add the initialization call to main.
77 InsertProfilingInitCall(Main, "llvm_start_basic_block_tracing");