path: root/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp

//===----- JITDwarfEmitter.cpp - Write dwarf tables into memory -----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a JITDwarfEmitter object that is used by the JIT to
// write dwarf tables to memory.
//
//===----------------------------------------------------------------------===//

#include "JIT.h"
#include "JITDwarfEmitter.h"
#include "llvm/Function.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/JITCodeEmitter.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;

JITDwarfEmitter::JITDwarfEmitter(JIT& theJit) : MMI(0), Jit(theJit) {}


unsigned char* JITDwarfEmitter::EmitDwarfTable(MachineFunction& F, 
                                               JITCodeEmitter& jce,
                                               unsigned char* StartFunction,
                                               unsigned char* EndFunction,
                                               unsigned char* &EHFramePtr) {
  assert(MMI && "MachineModuleInfo not registered!");

  const TargetMachine& TM = F.getTarget();
  TD = TM.getTargetData();
  stackGrowthDirection = TM.getFrameInfo()->getStackGrowthDirection();
  RI = TM.getRegisterInfo();
  JCE = &jce;
  
  unsigned char* ExceptionTable = EmitExceptionTable(&F, StartFunction,
                                                     EndFunction);
      
  unsigned char* Result = 0;

  const std::vector<Function *> Personalities = MMI->getPersonalities();
  EHFramePtr = EmitCommonEHFrame(Personalities[MMI->getPersonalityIndex()]);

  Result = EmitEHFrame(Personalities[MMI->getPersonalityIndex()], EHFramePtr,
                       StartFunction, EndFunction, ExceptionTable);

  return Result;
}


void 
JITDwarfEmitter::EmitFrameMoves(intptr_t BaseLabelPtr,
                                const std::vector<MachineMove> &Moves) const {
  unsigned PointerSize = TD->getPointerSize();
  int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
          PointerSize : -PointerSize;
  MCSymbol *BaseLabel = 0;

  for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
    const MachineMove &Move = Moves[i];
    MCSymbol *Label = Move.getLabel();
    
    // Throw out move if the label is invalid.
    if (Label && !Label->isDefined())
      continue;
    
    intptr_t LabelPtr = 0;
    if (Label) LabelPtr = JCE->getLabelAddress(Label);

    const MachineLocation &Dst = Move.getDestination();
    const MachineLocation &Src = Move.getSource();
    
    // Advance row if new location.
    if (BaseLabelPtr && Label && BaseLabel != Label) {
      JCE->emitByte(dwarf::DW_CFA_advance_loc4);
      JCE->emitInt32(LabelPtr - BaseLabelPtr);
      
      BaseLabel = Label; 
      BaseLabelPtr = LabelPtr;
    }
    
    // If advancing cfa.
    if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
      if (!Src.isReg()) {
        if (Src.getReg() == MachineLocation::VirtualFP) {
          JCE->emitByte(dwarf::DW_CFA_def_cfa_offset);
        } else {
          JCE->emitByte(dwarf::DW_CFA_def_cfa);
          JCE->emitULEB128Bytes(RI->getDwarfRegNum(Src.getReg(), true));
        }
        
        JCE->emitULEB128Bytes(-Src.getOffset());
      } else {
        llvm_unreachable("Machine move not supported yet.");
      }
    } else if (Src.isReg() &&
      Src.getReg() == MachineLocation::VirtualFP) {
      if (Dst.isReg()) {
        JCE->emitByte(dwarf::DW_CFA_def_cfa_register);
        JCE->emitULEB128Bytes