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

//===-- X86/Printer.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 "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Mangler.h"
#include "Support/Statistic.h"
#include "Support/StringExtras.h"
#include "Support/CommandLine.h"

namespace llvm {

namespace {
  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");

  // FIXME: This should be automatically picked up by autoconf from the C
  // frontend
  cl::opt<bool> EmitCygwin("enable-cygwin-compatible-output", cl::Hidden,
         cl::desc("Emit X86 assembly code suitable for consumption by cygwin"));

  struct Printer : public MachineFunctionPass {
    /// Output stream on which we're printing assembly code.
    ///
    std::ostream &O;

    /// Target machine description which we query for reg. names, data
    /// layout, etc.
    ///
    TargetMachine &TM;

    /// Name-mangler for global names.
    ///
    Mangler *Mang;

    Printer(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) { }

    /// We name each basic block in a Function with a unique number, so
    /// that we can consistently refer to them later. This is cleared
    /// at the beginning of each call to runOnMachineFunction().
    ///
    typedef std::map<const Value *, unsigned> ValueMapTy;
    ValueMapTy NumberForBB;

    /// Cache of mangled name for current function. This is
    /// recalculated at the beginning of each call to
    /// runOnMachineFunction().
    ///
    std::string CurrentFnName;

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

    void checkImplUses (const TargetInstrDescriptor &Desc);
    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);
    void emitGlobalConstant(const Constant* CV);
    void emitConstantValueOnly(const Constant *CV);
  };
} // 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 *createX86CodePrinterPass(std::ostream &o,TargetMachine &tm){
  return new Printer(o, tm);
}

/// isStringCompatible - Can we treat the specified array as a string?
/// Only if it is an array of ubytes or non-negative sbytes.
///
static bool isStringCompatible(const ConstantArray *CVA) {
  const Type *ETy = cast<ArrayType>(CVA->getType())->getElementType();
  if (ETy == Type::UByteTy) return true;
  if (ETy != Type::SByteTy) return false;

  for (unsigned i = 0; i < CVA->getNumOperands(); ++i)
    if (cast<ConstantSInt>(CVA->getOperand(i))->getValue() < 0)
      return false;

  return true;
}

/// toOctal - Convert the low order bits of X into an octal digit.
///
static inline char toOctal(int X) {
  return (X&7)+'0';
}

/// getAsCString - Return the specified array as a C compatible
/// string, only if the predicate isStringCompatible is true.
///
static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
  assert(isStringCompatible(CVA) && "Array is not string compatible!");

  O << "\"";
  for (unsigned i = 0; i < CVA->getNumOperands(); ++i) {
    unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();

    if (C == '"') {
      O << "\\\"";
    } else if (C == '\\') {
      O << "\\\\";
    } else if (isprint(C)) {
      O << C;
    } else {
      switch(C</