path: root/lib/Target/X86/X86AsmPrinter.cpp

//===-- X86AsmPrinter.cpp - Convert X86 LLVM code to Intel assembly -------===//
// 
//                     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 contains a printer that converts from our internal representation
// of machine-dependent LLVM code to Intel-format assembly language. This
// printer is the output mechanism used by `llc' and `lli -print-machineinstrs'
// on X86.
//
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86InstrInfo.h"
#include "X86TargetMachine.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Mangler.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;

namespace {
  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
  enum AsmWriterFlavor { att, intel };

  cl::opt<AsmWriterFlavor>
  AsmWriterFlavor("x86-asm-syntax",
                  cl::desc("Choose style of code to emit from X86 backend:"),
                  cl::values(
                             clEnumVal(att, "  Emit AT&T Style"),
                             clEnumVal(intel, "  Emit Intel Style"),
                             clEnumValEnd),
                  cl::init(intel));

  struct GasBugWorkaroundEmitter : public MachineCodeEmitter {
    GasBugWorkaroundEmitter(std::ostream& o) 
      : O(o), OldFlags(O.flags()), firstByte(true) {
      O << std::hex;
    }

    ~GasBugWorkaroundEmitter() {
      O.flags(OldFlags);
    }

    virtual void emitByte(unsigned char B) {
      if (!firstByte) O << "\n\t";
      firstByte = false;
      O << ".byte 0x" << (unsigned) B;
    }

    // These should never be called
    virtual void emitWord(unsigned W) { assert(0); }
    virtual uint64_t getGlobalValueAddress(GlobalValue *V) { abort(); }
    virtual uint64_t getGlobalValueAddress(const std::string &Name) { abort(); }
    virtual uint64_t getConstantPoolEntryAddress(unsigned Index) { abort(); }
    virtual uint64_t getCurrentPCValue() { abort(); }
    virtual uint64_t forceCompilationOf(Function *F) { abort(); }

  private:
    std::ostream& O;
    std::ios::fmtflags OldFlags;
    bool firstByte;
  };

  struct X86IntelAsmPrinter : public AsmPrinter {
    X86IntelAsmPrinter(std::ostream &O, TargetMachine &TM) : AsmPrinter(O, TM) { }

    virtual const char *getPassName() const {
      return "X86 Assembly Printer";
    }

    /// printInstruction - This method is automatically generated by tablegen
    /// from the instruction set description.  This method returns true if the
    /// machine instruction was sufficiently described to print it, otherwise it
    /// returns false.
    bool printInstruction(const MachineInstr *MI);

    // This method is used by the tablegen'erated instruction printer.
    void printOperand(const MachineInstr *MI, unsigned OpNo, MVT::ValueType VT){
      const MachineOperand &MO = MI->getOperand(OpNo);
      if (MO.getType() == MachineOperand::MO_MachineRegister) {
        assert(MRegisterInfo::isPhysicalRegister(MO.getReg())&&"Not physref??");
        // Bug Workaround: See note in Printer::doInitialization about %.
        O << "%" << TM.getRegisterInfo()->get(MO.getReg()).Name;
      } else {
        printOp(MO);
      }
    }

    void printCallOperand(const MachineInstr *MI, unsigned OpNo,
                          MVT::ValueType VT) {
      printOp(MI->getOperand(OpNo), true); // Don't print "OFFSET".
    }

    void printMemoryOperand(const MachineInstr *MI, unsigned OpNo,
                            MVT::ValueType VT) {
      switch (VT) {
      default: assert(0 && "Unknown arg size!");
      case MVT::i8:   O << "BYTE PTR "; break;
      case MVT::i16:  O << "WORD PTR "; break;
      case MVT::i32:
      case MVT::f32:  O << "DWORD PTR "; break;
      case MVT::i64:
      case MVT::f64:  O << "QWORD PTR "; break;
      case MVT::f80:  O << "XWORD PTR "; break;
      }
      printMemReference(MI, OpNo);
    }

    void printMachineInstruction(const MachineInstr *MI);
    void printOp(const MachineOperand &MO, bool elideOffsetKeyword = false);
    void printMemReference(const MachineInstr *MI, unsigned Op);
    void printConstantPool(MachineConstantPool *MCP);
    bool runOnMachineFunction(MachineFunction &F);    
    bool doInitialization(Module &M);
    bool doFinalization(Module &M);
  };
} // end of anonymous namespace

/// createX86CodePrinterPass - Returns a pass that prints the X86
/// assembly code for a MachineFunction to the given output stream,
/// using the given target machine description.  This should work
/// regardless of whether the function is in SSA form.
///
FunctionPass *llvm::createX86CodePrinterPass(std::ostream &o,TargetMachine &tm){
  if (AsmWriterFlavor != intel) {
    std::cerr << "AT&T syntax not fully implemented yet!\n";
    abort();
  }

  return new X86IntelAsmPrinter(o, tm);
}


// Include the auto-generated portion of the assembly writer.
#include "X86GenIntelAsmWriter.inc"


/// printConstantPool - Print to the current output stream assembly
/// representations of the constants in the constant pool MCP. This is
/// used to print out constants which have been "spilled to memory" by
/// the code generator.
///
void X86IntelAsmPrinter::printConstantPool(MachineConstantPool *MCP) {
  const std::vector<Constant*> &CP = MCP->getConstants();
  const TargetData &TD = TM.getTargetData();
 
  if (CP.empty()) return;

  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
    O << "\t.section .rodata\n";
    emitAlignment(TD.getTypeAlignmentShift(CP[i]->getType()));
    O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t" << CommentString
      << *CP[i] << "\n";
    emitGlobalConstant(CP[i]);
  }
}

/// runOnMachineFunction - This uses the printMachineInstruction()
/// method to print assembly for each instruction.
///
bool X86IntelAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
  setupMachineFunction(MF);
  O << "\n\n";

  // Print out constants referenced by the function
  printConstantPool(MF.getConstantPool());

  // Print out labels for the function.
  O << "\t.text\n";
  emitAlignment(4);
  O << "\t.globl\t" << CurrentFnName << "\n";
  O << "\t.type\t" << CurrentFnName << ", @function\n";
  O << CurrentFnName << ":\n";

  // Print out code for the function.
  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
       I != E; ++I) {
    // Print a label for the basic block.
    O << ".LBB" << CurrentFnName << "_" << I->getNumber() << ":\t"
      << CommentString << " " << I->getBasicBlock()->getName() << "\n";
    for (MachineBasicBlock::const_iterator II = I->begin(), E = I-&