llvm-6502/lib/Target/MBlaze/MBlazeAsmPrinter.cpp

321 lines
11 KiB
C++

//===-- MBlazeAsmPrinter.cpp - MBlaze LLVM assembly writer ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file 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 GAS-format MBlaze assembly language.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mblaze-asm-printer"
#include "MBlaze.h"
#include "MBlazeSubtarget.h"
#include "MBlazeInstrInfo.h"
#include "MBlazeTargetMachine.h"
#include "MBlazeMachineFunction.h"
#include "MBlazeMCInstLower.h"
#include "InstPrinter/MBlazeInstPrinter.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include <cctype>
using namespace llvm;
namespace {
class MBlazeAsmPrinter : public AsmPrinter {
const MBlazeSubtarget *Subtarget;
public:
explicit MBlazeAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
: AsmPrinter(TM, Streamer) {
Subtarget = &TM.getSubtarget<MBlazeSubtarget>();
}
virtual const char *getPassName() const {
return "MBlaze Assembly Printer";
}
void printSavedRegsBitmask();
void emitFrameDirective();
virtual void EmitFunctionBodyStart();
virtual void EmitFunctionBodyEnd();
virtual void EmitFunctionEntryLabel();
virtual bool isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB)
const;
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant, const char *ExtraCode,
raw_ostream &O);
void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O);
void printUnsignedImm(const MachineInstr *MI, int opNum, raw_ostream &O);
void printFSLImm(const MachineInstr *MI, int opNum, raw_ostream &O);
void printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier = 0);
void EmitInstruction(const MachineInstr *MI);
};
} // end of anonymous namespace
// #include "MBlazeGenAsmWriter.inc"
//===----------------------------------------------------------------------===//
//
// MBlaze Asm Directives
//
// -- Frame directive "frame Stackpointer, Stacksize, RARegister"
// Describe the stack frame.
//
// -- Mask directives "mask bitmask, offset"
// Tells the assembler which registers are saved and where.
// bitmask - contain a little endian bitset indicating which registers are
// saved on function prologue (e.g. with a 0x80000000 mask, the
// assembler knows the register 31 (RA) is saved at prologue.
// offset - the position before stack pointer subtraction indicating where
// the first saved register on prologue is located. (e.g. with a
//
// Consider the following function prologue:
//
// .frame R19,48,R15
// .mask 0xc0000000,-8
// addiu R1, R1, -48
// sw R15, 40(R1)
// sw R19, 36(R1)
//
// With a 0xc0000000 mask, the assembler knows the register 15 (R15) and
// 19 (R19) are saved at prologue. As the save order on prologue is from
// left to right, R15 is saved first. A -8 offset means that after the
// stack pointer subtration, the first register in the mask (R15) will be
// saved at address 48-8=40.
//
//===----------------------------------------------------------------------===//
// Print a 32 bit hex number with all numbers.
static void printHex32(unsigned int Value, raw_ostream &O) {
O << "0x";
for (int i = 7; i >= 0; i--)
O.write_hex((Value & (0xF << (i*4))) >> (i*4));
}
// Create a bitmask with all callee saved registers for CPU or Floating Point
// registers. For CPU registers consider RA, GP and FP for saving if necessary.
void MBlazeAsmPrinter::printSavedRegsBitmask() {
const TargetFrameLowering *TFI = TM.getFrameLowering();
const TargetRegisterInfo &RI = *TM.getRegisterInfo();
// CPU Saved Registers Bitmasks
unsigned int CPUBitmask = 0;
// Set the CPU Bitmasks
const MachineFrameInfo *MFI = MF->getFrameInfo();
const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg();
unsigned RegNum = getMBlazeRegisterNumbering(Reg);
if (MBlaze::GPRRegClass.contains(Reg))
CPUBitmask |= (1 << RegNum);
}
// Return Address and Frame registers must also be set in CPUBitmask.
if (TFI->hasFP(*MF))
CPUBitmask |= (1 << getMBlazeRegisterNumbering(RI.getFrameRegister(*MF)));
if (MFI->adjustsStack())
CPUBitmask |= (1 << getMBlazeRegisterNumbering(RI.getRARegister()));
// Print CPUBitmask
OutStreamer.EmitRawText("\t.mask\t0x" + Twine::utohexstr(CPUBitmask));
}
/// Frame Directive
void MBlazeAsmPrinter::emitFrameDirective() {
if (!OutStreamer.hasRawTextSupport())
return;
const TargetRegisterInfo &RI = *TM.getRegisterInfo();
unsigned stkReg = RI.getFrameRegister(*MF);
unsigned retReg = RI.getRARegister();
unsigned stkSze = MF->getFrameInfo()->getStackSize();
OutStreamer.EmitRawText("\t.frame\t" +
Twine(MBlazeInstPrinter::getRegisterName(stkReg)) +
"," + Twine(stkSze) + "," +
Twine(MBlazeInstPrinter::getRegisterName(retReg)));
}
void MBlazeAsmPrinter::EmitFunctionEntryLabel() {
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText("\t.ent\t" + Twine(CurrentFnSym->getName()));
AsmPrinter::EmitFunctionEntryLabel();
}
void MBlazeAsmPrinter::EmitFunctionBodyStart() {
if (!OutStreamer.hasRawTextSupport())
return;
emitFrameDirective();
printSavedRegsBitmask();
}
void MBlazeAsmPrinter::EmitFunctionBodyEnd() {
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText("\t.end\t" + Twine(CurrentFnSym->getName()));
}
//===----------------------------------------------------------------------===//
void MBlazeAsmPrinter::EmitInstruction(const MachineInstr *MI) {
MBlazeMCInstLower MCInstLowering(OutContext, *Mang, *this);
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
OutStreamer.EmitInstruction(TmpInst);
}
// Print out an operand for an inline asm expression.
bool MBlazeAsmPrinter::
PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant,const char *ExtraCode, raw_ostream &O) {
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0])
return true; // Unknown modifier.
printOperand(MI, OpNo, O);
return false;
}
void MBlazeAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(opNum);
switch (MO.getType()) {
case MachineOperand::MO_Register:
O << MBlazeInstPrinter::getRegisterName(MO.getReg());
break;
case MachineOperand::MO_Immediate:
O << (int32_t)MO.getImm();
break;
case MachineOperand::MO_FPImmediate: {
const ConstantFP *fp = MO.getFPImm();
printHex32(fp->getValueAPF().bitcastToAPInt().getZExtValue(), O);
O << ";\t# immediate = " << *fp;
break;
}
case MachineOperand::MO_MachineBasicBlock:
O << *MO.getMBB()->getSymbol();
return;
case MachineOperand::MO_GlobalAddress:
O << *Mang->getSymbol(MO.getGlobal());
break;
case MachineOperand::MO_ExternalSymbol:
O << *GetExternalSymbolSymbol(MO.getSymbolName());
break;
case MachineOperand::MO_JumpTableIndex:
O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
<< '_' << MO.getIndex();
break;
case MachineOperand::MO_ConstantPoolIndex:
O << MAI->getPrivateGlobalPrefix() << "CPI"
<< getFunctionNumber() << "_" << MO.getIndex();
if (MO.getOffset())
O << "+" << MO.getOffset();
break;
default:
llvm_unreachable("<unknown operand type>");
}
}
void MBlazeAsmPrinter::printUnsignedImm(const MachineInstr *MI, int opNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(opNum);
if (MO.isImm())
O << (uint32_t)MO.getImm();
else
printOperand(MI, opNum, O);
}
void MBlazeAsmPrinter::printFSLImm(const MachineInstr *MI, int opNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(opNum);
if (MO.isImm())
O << "rfsl" << (unsigned int)MO.getImm();
else
printOperand(MI, opNum, O);
}
void MBlazeAsmPrinter::
printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier) {
printOperand(MI, opNum, O);
O << ", ";
printOperand(MI, opNum+1, O);
}
/// isBlockOnlyReachableByFallthough - Return true if the basic block has
/// exactly one predecessor and the control transfer mechanism between
/// the predecessor and this block is a fall-through.
bool MBlazeAsmPrinter::
isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
// If this is a landing pad, it isn't a fall through. If it has no preds,
// then nothing falls through to it.
if (MBB->isLandingPad() || MBB->pred_empty())
return false;
// If there isn't exactly one predecessor, it can't be a fall through.
MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
++PI2;
if (PI2 != MBB->pred_end())
return false;
// The predecessor has to be immediately before this block.
const MachineBasicBlock *Pred = *PI;
if (!Pred->isLayoutSuccessor(MBB))
return false;
// If the block is completely empty, then it definitely does fall through.
if (Pred->empty())
return true;
// Check if the last terminator is an unconditional branch.
MachineBasicBlock::const_iterator I = Pred->end();
while (I != Pred->begin() && !(--I)->isTerminator())
; // Noop
return I == Pred->end() || !I->isBarrier();
}
// Force static initialization.
extern "C" void LLVMInitializeMBlazeAsmPrinter() {
RegisterAsmPrinter<MBlazeAsmPrinter> X(TheMBlazeTarget);
}