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llvm-6502/lib/Target/Mips/MipsAsmPrinter.cpp
Jack Carter a0f14afee1 Mips specific inline asm operand modifier 'M': 
Print the high order register of a double word register operand.

In 32 bit mode, a 64 bit double word integer will be represented
by 2 32 bit registers. This modifier causes the high order register
to be used in the asm expression. It is useful if you are using 
doubles in assembler and continue to control register to variable
relationships.

This patch also fixes a related bug in a previous patch:

    case 'D': // Second part of a double word register operand
    case 'L': // Low order register of a double word register operand
    case 'M': // High order register of a double word register operand

I got 'D' and 'M' confused. The second part of a double word operand
will only match 'M' for one of the endianesses. I had 'L' and 'D'
be the opposite twins when 'L' and 'M' are.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160429 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-18 06:41:36 +00:00

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//===-- MipsAsmPrinter.cpp - Mips LLVM Assembly Printer -------------------===//
//
// 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 MIPS assembly language.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-asm-printer"
#include "Mips.h"
#include "MipsAsmPrinter.h"
#include "MipsInstrInfo.h"
#include "MipsMCInstLower.h"
#include "InstPrinter/MipsInstPrinter.h"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BasicBlock.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
MipsFI = MF.getInfo<MipsFunctionInfo>();
AsmPrinter::runOnMachineFunction(MF);
return true;
}
void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) {
if (MI->isDebugValue()) {
SmallString<128> Str;
raw_svector_ostream OS(Str);
PrintDebugValueComment(MI, OS);
return;
}
// Direct object specific instruction lowering
if (!OutStreamer.hasRawTextSupport())
switch (MI->getOpcode()) {
case Mips::DSLL:
case Mips::DSRL:
case Mips::DSRA:
assert(MI->getNumOperands() == 3 &&
"Invalid no. of machine operands for shift!");
assert(MI->getOperand(2).isImm());
int64_t Shift = MI->getOperand(2).getImm();
if (Shift > 31) {
MCInst TmpInst0;
MCInstLowering.LowerLargeShift(MI, TmpInst0, Shift - 32);
OutStreamer.EmitInstruction(TmpInst0);
return;
}
break;
}
MachineBasicBlock::const_instr_iterator I = MI;
MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
do {
MCInst TmpInst0;
MCInstLowering.Lower(I++, TmpInst0);
OutStreamer.EmitInstruction(TmpInst0);
} while ((I != E) && I->isInsideBundle());
}
//===----------------------------------------------------------------------===//
//
// Mips Asm Directives
//
// -- Frame directive "frame Stackpointer, Stacksize, RARegister"
// Describe the stack frame.
//
// -- Mask directives "(f)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 $fp,48,$ra
// .mask 0xc0000000,-8
// addiu $sp, $sp, -48
// sw $ra, 40($sp)
// sw $fp, 36($sp)
//
// With a 0xc0000000 mask, the assembler knows the register 31 (RA) and
// 30 (FP) are saved at prologue. As the save order on prologue is from
// left to right, RA is saved first. A -8 offset means that after the
// stack pointer subtration, the first register in the mask (RA) will be
// saved at address 48-8=40.
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// Mask directives
//===----------------------------------------------------------------------===//
// 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 MipsAsmPrinter::printSavedRegsBitmask(raw_ostream &O) {
// CPU and FPU Saved Registers Bitmasks
unsigned CPUBitmask = 0, FPUBitmask = 0;
int CPUTopSavedRegOff, FPUTopSavedRegOff;
// Set the CPU and FPU Bitmasks
const MachineFrameInfo *MFI = MF->getFrameInfo();
const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
// size of stack area to which FP callee-saved regs are saved.
unsigned CPURegSize = Mips::CPURegsRegClass.getSize();
unsigned FGR32RegSize = Mips::FGR32RegClass.getSize();
unsigned AFGR64RegSize = Mips::AFGR64RegClass.getSize();
bool HasAFGR64Reg = false;
unsigned CSFPRegsSize = 0;
unsigned i, e = CSI.size();
// Set FPU Bitmask.
for (i = 0; i != e; ++i) {
unsigned Reg = CSI[i].getReg();
if (Mips::CPURegsRegClass.contains(Reg))
break;
unsigned RegNum = getMipsRegisterNumbering(Reg);
if (Mips::AFGR64RegClass.contains(Reg)) {
FPUBitmask |= (3 << RegNum);
CSFPRegsSize += AFGR64RegSize;
HasAFGR64Reg = true;
continue;
}
FPUBitmask |= (1 << RegNum);
CSFPRegsSize += FGR32RegSize;
}
// Set CPU Bitmask.
for (; i != e; ++i) {
unsigned Reg = CSI[i].getReg();
unsigned RegNum = getMipsRegisterNumbering(Reg);
CPUBitmask |= (1 << RegNum);
}
// FP Regs are saved right below where the virtual frame pointer points to.
FPUTopSavedRegOff = FPUBitmask ?
(HasAFGR64Reg ? -AFGR64RegSize : -FGR32RegSize) : 0;
// CPU Regs are saved below FP Regs.
CPUTopSavedRegOff = CPUBitmask ? -CSFPRegsSize - CPURegSize : 0;
// Print CPUBitmask
O << "\t.mask \t"; printHex32(CPUBitmask, O);
O << ',' << CPUTopSavedRegOff << '\n';
// Print FPUBitmask
O << "\t.fmask\t"; printHex32(FPUBitmask, O);
O << "," << FPUTopSavedRegOff << '\n';
}
// Print a 32 bit hex number with all numbers.
void MipsAsmPrinter::printHex32(unsigned Value, raw_ostream &O) {
O << "0x";
for (int i = 7; i >= 0; i--)
O.write_hex((Value & (0xF << (i*4))) >> (i*4));
}
//===----------------------------------------------------------------------===//
// Frame and Set directives
//===----------------------------------------------------------------------===//
/// Frame Directive
void MipsAsmPrinter::emitFrameDirective() {
const TargetRegisterInfo &RI = *TM.getRegisterInfo();
unsigned stackReg = RI.getFrameRegister(*MF);
unsigned returnReg = RI.getRARegister();
unsigned stackSize = MF->getFrameInfo()->getStackSize();
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText("\t.frame\t$" +
StringRef(MipsInstPrinter::getRegisterName(stackReg)).lower() +
"," + Twine(stackSize) + ",$" +
StringRef(MipsInstPrinter::getRegisterName(returnReg)).lower());
}
/// Emit Set directives.
const char *MipsAsmPrinter::getCurrentABIString() const {
switch (Subtarget->getTargetABI()) {
case MipsSubtarget::O32: return "abi32";
case MipsSubtarget::N32: return "abiN32";
case MipsSubtarget::N64: return "abi64";
case MipsSubtarget::EABI: return "eabi32"; // TODO: handle eabi64
default: llvm_unreachable("Unknown Mips ABI");;
}
}
void MipsAsmPrinter::EmitFunctionEntryLabel() {
if (OutStreamer.hasRawTextSupport()) {
if (Subtarget->inMips16Mode())
OutStreamer.EmitRawText(StringRef("\t.set\tmips16"));
else
OutStreamer.EmitRawText(StringRef("\t.set\tnomips16"));
// leave out until FSF available gas has micromips changes
// OutStreamer.EmitRawText(StringRef("\t.set\tnomicromips"));
OutStreamer.EmitRawText("\t.ent\t" + Twine(CurrentFnSym->getName()));
}
OutStreamer.EmitLabel(CurrentFnSym);
}
/// EmitFunctionBodyStart - Targets can override this to emit stuff before
/// the first basic block in the function.
void MipsAsmPrinter::EmitFunctionBodyStart() {
MCInstLowering.Initialize(Mang, &MF->getContext());
emitFrameDirective();
if (OutStreamer.hasRawTextSupport()) {
SmallString<128> Str;
raw_svector_ostream OS(Str);
printSavedRegsBitmask(OS);
OutStreamer.EmitRawText(OS.str());
OutStreamer.EmitRawText(StringRef("\t.set\tnoreorder"));
OutStreamer.EmitRawText(StringRef("\t.set\tnomacro"));
if (MipsFI->getEmitNOAT())
OutStreamer.EmitRawText(StringRef("\t.set\tnoat"));
}
}
/// EmitFunctionBodyEnd - Targets can override this to emit stuff after
/// the last basic block in the function.
void MipsAsmPrinter::EmitFunctionBodyEnd() {
// There are instruction for this macros, but they must
// always be at the function end, and we can't emit and
// break with BB logic.
if (OutStreamer.hasRawTextSupport()) {
if (MipsFI->getEmitNOAT())
OutStreamer.EmitRawText(StringRef("\t.set\tat"));
OutStreamer.EmitRawText(StringRef("\t.set\tmacro"));
OutStreamer.EmitRawText(StringRef("\t.set\treorder"));
OutStreamer.EmitRawText("\t.end\t" + Twine(CurrentFnSym->getName()));
}
}
/// 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 MipsAsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock*
MBB) const {
// The predecessor has to be immediately before this block.
const MachineBasicBlock *Pred = *MBB->pred_begin();
// If the predecessor is a switch statement, assume a jump table
// implementation, so it is not a fall through.
if (const BasicBlock *bb = Pred->getBasicBlock())
if (isa<SwitchInst>(bb->getTerminator()))
return false;
// 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.
if (!Pred->isLayoutSuccessor(MBB))
return false;
// If the block is completely empty, then it definitely does fall through.
if (Pred->empty())
return true;
// Otherwise, check the last instruction.
// Check if the last terminator is an unconditional branch.
MachineBasicBlock::const_iterator I = Pred->end();
while (I != Pred->begin() && !(--I)->isTerminator()) ;
return !I->isBarrier();
}
// Print out an operand for an inline asm expression.
bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
unsigned AsmVariant,const char *ExtraCode,
raw_ostream &O) {
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0) return true; // Unknown modifier.
const MachineOperand &MO = MI->getOperand(OpNum);
switch (ExtraCode[0]) {
default:
// See if this is a generic print operand
return AsmPrinter::PrintAsmOperand(MI,OpNum,AsmVariant,ExtraCode,O);
case 'X': // hex const int
if ((MO.getType()) != MachineOperand::MO_Immediate)
return true;
O << "0x" << StringRef(utohexstr(MO.getImm())).lower();
return false;
case 'x': // hex const int (low 16 bits)
if ((MO.getType()) != MachineOperand::MO_Immediate)
return true;
O << "0x" << StringRef(utohexstr(MO.getImm() & 0xffff)).lower();
return false;
case 'd': // decimal const int
if ((MO.getType()) != MachineOperand::MO_Immediate)
return true;
O << MO.getImm();
return false;
case 'm': // decimal const int minus 1
if ((MO.getType()) != MachineOperand::MO_Immediate)
return true;
O << MO.getImm() - 1;
return false;
case 'z': {
// $0 if zero, regular printing otherwise
if (MO.getType() != MachineOperand::MO_Immediate)
return true;
int64_t Val = MO.getImm();
if (Val)
O << Val;
else
O << "$0";
return false;
}
case 'D': // Second part of a double word register operand
case 'L': // Low order register of a double word register operand
case 'M': // High order register of a double word register operand
{
if (OpNum == 0)
return true;
const MachineOperand &FlagsOP = MI->getOperand(OpNum - 1);
if (!FlagsOP.isImm())
return true;
unsigned Flags = FlagsOP.getImm();
unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
// Number of registers represented by this operand. We are looking
// for 2 for 32 bit mode and 1 for 64 bit mode.
if (NumVals != 2) {
if (Subtarget->isGP64bit() && NumVals == 1 && MO.isReg()) {
unsigned Reg = MO.getReg();
O << '$' << MipsInstPrinter::getRegisterName(Reg);
return false;
}
return true;
}
unsigned RegOp = OpNum;
if (!Subtarget->isGP64bit()){
// Endianess reverses which register holds the high or low value
// between M and L.
switch(ExtraCode[0]) {
case 'M':
RegOp = (Subtarget->isLittle()) ? OpNum + 1 : OpNum;
break;
case 'L':
RegOp = (Subtarget->isLittle()) ? OpNum : OpNum + 1;
break;
case 'D': // Always the second part
RegOp = OpNum + 1;
}
if (RegOp >= MI->getNumOperands())
return true;
const MachineOperand &MO = MI->getOperand(RegOp);
if (!MO.isReg())
return true;
unsigned Reg = MO.getReg();
O << '$' << MipsInstPrinter::getRegisterName(Reg);
return false;
}
}
}
}
printOperand(MI, OpNum, O);
return false;
}
bool MipsAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNum, unsigned AsmVariant,
const char *ExtraCode,
raw_ostream &O) {
if (ExtraCode && ExtraCode[0])
return true; // Unknown modifier.
const MachineOperand &MO = MI->getOperand(OpNum);
assert(MO.isReg() && "unexpected inline asm memory operand");
O << "0($" << MipsInstPrinter::getRegisterName(MO.getReg()) << ")";
return false;
}
void MipsAsmPrinter::printOperand(const MachineInstr *MI, int opNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(opNum);
bool closeP = false;
if (MO.getTargetFlags())
closeP = true;
switch(MO.getTargetFlags()) {
case MipsII::MO_GPREL: O << "%gp_rel("; break;
case MipsII::MO_GOT_CALL: O << "%call16("; break;
case MipsII::MO_GOT: O << "%got("; break;
case MipsII::MO_ABS_HI: O << "%hi("; break;
case MipsII::MO_ABS_LO: O << "%lo("; break;
case MipsII::MO_TLSGD: O << "%tlsgd("; break;
case MipsII::MO_GOTTPREL: O << "%gottprel("; break;
case MipsII::MO_TPREL_HI: O << "%tprel_hi("; break;
case MipsII::MO_TPREL_LO: O << "%tprel_lo("; break;
case MipsII::MO_GPOFF_HI: O << "%hi(%neg(%gp_rel("; break;
case MipsII::MO_GPOFF_LO: O << "%lo(%neg(%gp_rel("; break;
case MipsII::MO_GOT_DISP: O << "%got_disp("; break;
case MipsII::MO_GOT_PAGE: O << "%got_page("; break;
case MipsII::MO_GOT_OFST: O << "%got_ofst("; break;
}
switch (MO.getType()) {
case MachineOperand::MO_Register:
O << '$'
<< StringRef(MipsInstPrinter::getRegisterName(MO.getReg())).lower();
break;
case MachineOperand::MO_Immediate:
O << MO.getImm();
break;
case MachineOperand::MO_MachineBasicBlock:
O << *MO.getMBB()->getSymbol();
return;
case MachineOperand::MO_GlobalAddress:
O << *Mang->getSymbol(MO.getGlobal());
break;
case MachineOperand::MO_BlockAddress: {
MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
O << BA->getName();
break;
}
case MachineOperand::MO_ExternalSymbol:
O << *GetExternalSymbolSymbol(MO.getSymbolName());
break;
case MachineOperand::MO_JumpTableIndex:
O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
<< '_' << MO.getIndex();
break;
case MachineOperand::MO_ConstantPoolIndex:
O << MAI->getPrivateGlobalPrefix() << "CPI"
<< getFunctionNumber() << "_" << MO.getIndex();
if (MO.getOffset())
O << "+" << MO.getOffset();
break;
default:
llvm_unreachable("<unknown operand type>");
}
if (closeP) O << ")";
}
void MipsAsmPrinter::printUnsignedImm(const MachineInstr *MI, int opNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(opNum);
if (MO.isImm())
O << (unsigned short int)MO.getImm();
else
printOperand(MI, opNum, O);
}
void MipsAsmPrinter::
printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O) {
// Load/Store memory operands -- imm($reg)
// If PIC target the target is loaded as the
// pattern lw $25,%call16($28)
printOperand(MI, opNum+1, O);
O << "(";
printOperand(MI, opNum, O);
O << ")";
}
void MipsAsmPrinter::
printMemOperandEA(const MachineInstr *MI, int opNum, raw_ostream &O) {
// when using stack locations for not load/store instructions
// print the same way as all normal 3 operand instructions.
printOperand(MI, opNum, O);
O << ", ";
printOperand(MI, opNum+1, O);
return;
}
void MipsAsmPrinter::
printFCCOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier) {
const MachineOperand &MO = MI->getOperand(opNum);
O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm());
}
void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
// FIXME: Use SwitchSection.
// Tell the assembler which ABI we are using
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText("\t.section .mdebug." +
Twine(getCurrentABIString()));
// TODO: handle O64 ABI
if (OutStreamer.hasRawTextSupport()) {
if (Subtarget->isABI_EABI()) {
if (Subtarget->isGP32bit())
OutStreamer.EmitRawText(StringRef("\t.section .gcc_compiled_long32"));
else
OutStreamer.EmitRawText(StringRef("\t.section .gcc_compiled_long64"));
}
}
// return to previous section
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText(StringRef("\t.previous"));
}
MachineLocation
MipsAsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
// Handles frame addresses emitted in MipsInstrInfo::emitFrameIndexDebugValue.
assert(MI->getNumOperands() == 4 && "Invalid no. of machine operands!");
assert(MI->getOperand(0).isReg() && MI->getOperand(1).isImm() &&
"Unexpected MachineOperand types");
return MachineLocation(MI->getOperand(0).getReg(),
MI->getOperand(1).getImm());
}
void MipsAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
raw_ostream &OS) {
// TODO: implement
}
// Force static initialization.
extern "C" void LLVMInitializeMipsAsmPrinter() {
RegisterAsmPrinter<MipsAsmPrinter> X(TheMipsTarget);
RegisterAsmPrinter<MipsAsmPrinter> Y(TheMipselTarget);
RegisterAsmPrinter<MipsAsmPrinter> A(TheMips64Target);
RegisterAsmPrinter<MipsAsmPrinter> B(TheMips64elTarget);
}
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