path: root/lib/Debugger/ProgramInfo.cpp

//===-- ProgramInfo.cpp - Compute and cache info about a program ----------===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
// 
// This file implements the ProgramInfo and related classes, by sorting through
// the loaded Module.
//
//===----------------------------------------------------------------------===//

#include "llvm/Debugger/ProgramInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Intrinsics.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Debugger/SourceFile.h"
#include "llvm/Debugger/SourceLanguage.h"
#include "Support/FileUtilities.h"
#include "Support/SlowOperationInformer.h"
#include "Support/STLExtras.h"
#include <iostream>

using namespace llvm;

/// getGlobalVariablesUsing - Return all of the global variables which have the
/// specified value in their initializer somewhere.
static void getGlobalVariablesUsing(Value *V,
                                    std::vector<GlobalVariable*> &Found) {
  for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
    if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I))
      Found.push_back(GV);
    else if (Constant *C = dyn_cast<Constant>(*I))
      getGlobalVariablesUsing(C, Found);
  }
}

/// getStringValue - Turn an LLVM constant pointer that eventually points to a
/// global into a string value.  Return an empty string if we can't do it.
///
static std::string getStringValue(Value *V, unsigned Offset = 0) {
  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
    if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
      ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
      if (Init->isString()) {
        std::string Result = Init->getAsString();
        if (Offset < Result.size()) {
          // If we are pointing INTO The string, erase the beginning...
          Result.erase(Result.begin(), Result.begin()+Offset);

          // Take off the null terminator, and any string fragments after it.
          std::string::size_type NullPos = Result.find_first_of((char)0);
          if (NullPos != std::string::npos)
            Result.erase(Result.begin()+NullPos, Result.end());
          return Result;
        }
      }
    }
  } else if (Constant *C = dyn_cast<Constant>(V)) {
    if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
      return getStringValue(GV, Offset);
    else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
      if (CE->getOpcode() == Instruction::GetElementPtr) {
        // Turn a gep into the specified offset.
        if (CE->getNumOperands() == 3 &&
            cast<Constant>(CE->getOperand(1))->isNullValue() &&
            isa<ConstantInt>(CE->getOperand(2))) {
          return getStringValue(CE->getOperand(0),
                   Offset+cast<ConstantInt>(CE->getOperand(2))->getRawValue());
        }
      }
    }
  }
  return "";
}

/// getNextStopPoint - Follow the def-use chains of the specified LLVM value,
/// traversing the use chains until we get to a stoppoint.  When we do, return
/// the source location of the stoppoint.  If we don't find a stoppoint, return
/// null.
static const GlobalVariable *getNextStopPoint(const Value *V, unsigned &LineNo,
                                              unsigned &ColNo) {
  // The use-def chains can fork.  As such, we pick the lowest numbered one we
  // find.
  const GlobalVariable *LastDesc = 0;
  unsigned LastLineNo = ~0;
  unsigned LastColNo = ~0;

  for (Value::use_const_iterator UI = V->use_begin(), E = V->use_end();
       UI != E; ++UI) {
    bool ShouldRecurse = true;
    if (cast<Instruction>(*UI)->getOpcode() == Instruction::PHI) {
      // Infinite loops == bad, ignore PHI nodes.
      ShouldRecurse = false;
    } else if (const CallInst *CI = dyn_cast<CallInst>(*UI)) {
      // If we found a stop point, check to see if it is earlier than what we
      // already have.  If so, remember it.
      if (const Function *F = CI->getCalledFunction())
        if (F->getIntrinsicID() == Intrinsic::dbg_stoppoint) {
          unsigned CurLineNo = ~0, CurColNo = ~0;
          const GlobalVariable *CurDesc = 0;
          if (const ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
            CurLineNo = C->getRawValue();
          if (const ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
            CurColNo = C->getRawValue();
          const Value *Op = CI->getOperand(4);
          
          if ((CurDesc = dyn_cast<GlobalVariable>(Op)) &&
              (LineNo < LastLineNo ||
               (LineNo == LastLineNo && ColNo < LastColNo))) {
            LastDesc = CurDesc;
            LastLineNo = CurLineNo;
            LastColNo = CurColNo;            
          }
          ShouldRecurse = false;
        }

    }

    // If this is not a phi node or a stopping point, recursively scan the users
    // of this instruction to skip over region.begin's and the like.
    if (ShouldRecurse) {
      unsigned CurLineNo, CurColNo;
      if (const GlobalVariable *GV = getNextStopPoint(*UI, CurLineNo,CurColNo)){
        if (LineNo < LastLineNo || (LineNo == LastLineNo && ColNo < LastColNo)){
          LastDesc = GV;
          LastLineNo = CurLineNo;
          LastColNo = CurColNo;            
        }
      }
    }
  }
  
  if (LastDesc) {
    LineNo = LastLineNo != ~0U ? LastLineNo : 0;
    ColNo  = LastColNo  != ~0U ? LastColNo : 0;
  }
  return LastDesc;
}


//===----------------------------------------------------------------------===//
// SourceFileInfo implementation
//

SourceFileInfo::SourceFileInfo(const GlobalVariable *Desc,
                               const SourceLanguage &Lang)
  : Language(&Lang), Descriptor(Desc) {
  Version = 0;
  SourceText = 0;

  if (Desc && Desc->hasInitializer())
    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Desc->getInitializer()))
      if (CS->getNumOperands() > 4) {
        if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(CS->getOperand(1)))
          Version = CUI->getValue();
        
        BaseName  = getStringValue(CS->getOperand(3));
        Directory = getStringValue(CS->getOperand(4));
      }
}

SourceFileInfo::~SourceFileInfo() {
  delete SourceText;
}

SourceFile &SourceFileInfo::getSourceText() const {
  // FIXME: this should take into account the source search directories!
  if (SourceText == 0)  // Read the file in if we haven't already.
    if (!Directory.empty() && FileOpenable(Directory+"/"+BaseName))
      SourceText = new SourceFile(Directory+"/"+BaseName, Descriptor);
    else
      SourceText = new SourceFile(BaseName, Descriptor);
  return *SourceText;
}


//===----------------------------------------------------------------------===//
// SourceFunctionInfo implementation
//
SourceFunctionInfo::SourceFunctionInfo(ProgramInfo &PI,
                                       const GlobalVariable *Desc)
  : Descriptor(Desc) {
  LineNo = ColNo = 0;
  if (Desc && Desc->hasInitializer())
    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(Desc->getInitializer()))
      if (CS->getNumOperands() > 2) {