path: root/lib/Transforms/Instrumentation/TraceValues.cpp

//===- TraceValues.cpp - Value Tracing for debugging -------------*- C++ -*--=//
//
// Support for inserting LLVM code to print values at basic block and function
// exits.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Instrumentation/TraceValues.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iMemory.h"
#include "llvm/iTerminators.h"
#include "llvm/iOther.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Assembly/Writer.h"
#include "Support/CommandLine.h"
#include "Support/StringExtras.h"
#include <algorithm>
#include <sstream>
using std::vector;
using std::string;

static cl::opt<bool>
DisablePtrHashing("tracedisablehashdisable", cl::Hidden,
                  cl::desc("Disable pointer hashing"));

static cl::list<string>
TraceFuncName("tracefunc", cl::desc("trace only specific functions"),
              cl::value_desc("function"), cl::Hidden);

static void TraceValuesAtBBExit(BasicBlock *BB,
                                Function *Printf, Function* HashPtrToSeqNum,
                                vector<Instruction*> *valuesStoredInFunction);

// We trace a particular function if no functions to trace were specified
// or if the function is in the specified list.
// 
inline static bool
TraceThisFunction(Function &func)
{
  if (TraceFuncName.size() == 0)
    return true;

  return std::find(TraceFuncName.begin(), TraceFuncName.end(), func.getName())
                  != TraceFuncName.end();
}


namespace {
  struct ExternalFuncs {
    Function *PrintfFunc, *HashPtrFunc, *ReleasePtrFunc;
    Function *RecordPtrFunc, *PushOnEntryFunc, *ReleaseOnReturnFunc;
    void doInitialization(Module &M); // Add prototypes for external functions
  };
  
  class InsertTraceCode : public FunctionPass {
  protected:
    ExternalFuncs externalFuncs;
  public:
    
    // Add a prototype for runtime functions not already in the program.
    //
    bool doInitialization(Module &M);
    
    //--------------------------------------------------------------------------
    // Function InsertCodeToTraceValues
    // 
    // Inserts tracing code for all live values at basic block and/or function
    // exits as specified by `traceBasicBlockExits' and `traceFunctionExits'.
    //
    bool doit(Function *M);

    virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) = 0;

    // runOnFunction - This method does the work.
    //
    bool runOnFunction(Function &F);

    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
      AU.preservesCFG();
    }
  };

  struct FunctionTracer : public InsertTraceCode {
    // Ignore basic blocks here...
    virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {}
  };

  struct BasicBlockTracer : public InsertTraceCode {
    // Trace basic blocks here...
    virtual void handleBasicBlock(BasicBlock *BB, vector<Instruction*> &VI) {
      TraceValuesAtBBExit(BB, externalFuncs.PrintfFunc,
                          externalFuncs.HashPtrFunc, &VI);
    }
  };

  // Register the passes...
  RegisterOpt<FunctionTracer>  X("tracem","Insert Function trace code only");
  RegisterOpt<BasicBlockTracer> Y("trace","Insert BB and Function trace code");
} // end anonymous namespace


Pass *createTraceValuesPassForFunction() {     // Just trace functions
  return new FunctionTracer();
}

Pass *createTraceValuesPassForBasicBlocks() {  // Trace BB's and functions
  return new BasicBlockTracer();
}


// Add a prototype for external functions used by the tracing code.
//
void ExternalFuncs::doInitialization(Module &M) {
  const Type *SBP = PointerType::get(Type::SByteTy);
  const FunctionType *MTy =
    FunctionType::get(Type::IntTy, vector<const Type*>(1, SBP), true);
  PrintfFunc = M.getOrInsertFunction("printf", MTy);

  // uint (sbyte*)
  const FunctionType *hashFuncTy =
    FunctionType::get(Type::UIntTy, vector<const Type*>(1, SBP), false);
  HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", hashFuncTy);
  
  // void (sbyte*)
  const FunctionType *voidSBPFuncTy =
    FunctionType::get(Type::VoidTy, vector<const Type*>(1, SBP), false);
  
  ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum", voidSBPFuncTy);
  RecordPtrFunc  = M.getOrInsertFunction("RecordPointer", voidSBPFuncTy);
  
  const FunctionType *voidvoidFuncTy =
    FunctionType::get(Type::VoidTy, vector<const Type*>(), false);
  
  PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", voidvoidFuncTy);
  ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
                                               voidvoidFuncTy);
}


// Add a prototype for external functions used by the tracing code.
//
bool InsertTraceCode::doInitialization(Module &M) {
  externalFuncs.doInitialization(M);
  return false;
}


static inline GlobalVariable *getStringRef(Module *M, const string &str) {
  // Create a constant internal string reference...
  Constant *Init = ConstantArray::get(str);

  // Create the global variable and record it in the module
  // The GV will be renamed to a unique name if needed.
  GlobalVariable *GV = new GlobalVariable(Init->getType(), true, true, Init,
                                          "trstr");
  M->getGlobalList().push_back(GV);
  return GV;
}


// 
// Check if this instruction has any uses outside its basic block,
// or if it used by either a Call or Return instruction.
// 
static inline bool LiveAtBBExit(const Instruction* I) {
  const BasicBlock *BB = I->getParent();
  for (Value::use_const_iterator U = I->use_begin(); U != I->use_end(); ++U)
    if (const Instruction *UI = dyn_cast<Instruction>(*U))
      if (UI->getParent() != BB || isa<ReturnInst>(UI))
        return true;

  return false;
}


static inline bool TraceThisOpCode(unsigned opCode) {
  // Explicitly test for opCodes *not* to trace so that any new opcodes will
  // be traced by default (VoidTy's are already excluded)
  // 
  return (opCode  < Instruction::FirstOtherOp &&
          opCode != Instruction::Alloca &&
          opCode != Instruction::PHINode &&
          opCode != Instruction::Cast);
}


static bool ShouldTraceValue(const Instruction *I) {
  return
    I->getType() != Type::VoidTy && LiveAtBBExit(I) &&
    TraceThisOpCode(I->getOpcode());
}

static string getPrintfCodeFor(const Value *V) {
  if (V == 0) return "";
  if (V->getType()->isFloatingPoint())
    return "%g";
  else if (V->getType() == Type::LabelTy)
    return "0x%p";
  else if (isa<PointerType>(V->getType()))
    return DisablePtrHashing ? "0x%p" : "%d";
  else if (V->getType()->isIntegral() || V->getType() == Type::BoolTy)
    return "%d";
  
  assert(0 && "Illegal value to print out...");
  return "";
}


static void InsertPrintInst(Value *V,BasicBlock *BB, BasicBlock::iterator &BBI,
                            string Message,
                            Function *Printf, Function* HashPtrToSeqNum) {
  // Escape Message by replacing all % characters with %% chars.
  unsigned Offset = 0;
  while ((Offset = Message.find('%', Offset)) != string::npos) {
    Message.replace(Offset,