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

//===-- X86/Printer.cpp - Convert X86 LLVM code to Intel assembly ---------===//
//
// 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 -printmachineinstrs' on X86.
//
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86InstrInfo.h"
#include "llvm/Function.h"
#include "llvm/Constant.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Type.h"
#include "llvm/Constants.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/DerivedTypes.h"
#include "Support/StringExtras.h"
#include "llvm/Module.h"
#include "llvm/Support/Mangler.h"

namespace {
  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 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);    
    std::string ConstantExprToString(const ConstantExpr* CE);
    std::string valToExprString(const Value* V);
    bool doInitialization(Module &M);
    bool doFinalization(Module &M);
    void printConstantValueOnly(const Constant* CV, int numPadBytesAfter = 0);
    void printSingleConstantValue(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.
///
Pass *createX86CodePrinterPass(std::ostream &o, TargetMachine &tm) {
  return new Printer(o, tm);
}

/// valToExprString - Helper function for ConstantExprToString().
/// Appends result to argument string S.
/// 
std::string Printer::valToExprString(const Value* V) {
  std::string S;
  bool failed = false;
  if (const Constant* CV = dyn_cast<Constant>(V)) { // symbolic or known
    if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV))
      S += std::string(CB == ConstantBool::True ? "1" : "0");
    else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV))
      S += itostr(CI->getValue());
    else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV))
      S += utostr(CI->getValue());
    else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
      S += ftostr(CFP->getValue());
    else if (isa<ConstantPointerNull>(CV))
      S += "0";
    else if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(CV))
      S += valToExprString(CPR->getValue());
    else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV))
      S += ConstantExprToString(CE);
    else
      failed = true;
  } else if (const GlobalValue* GV = dyn_cast<GlobalValue>(V)) {
    S += Mang->getValueName(GV);
  }
  else
    failed = true;

  if (failed) {
    assert(0 && "Cannot convert value to string");
    S += "<illegal-value>";
  }
  return S;
}

/// ConstantExprToString - Convert a ConstantExpr to an asm expression
/// and return this as a string.
///
std::string Printer::ConstantExprToString(const