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llvm-6502/lib/Target/Mips/MipsAsmPrinter.cpp

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//===-- MipsAsmPrinter.cpp - Mips 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 MIPS assembly language.
//
//===---------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-asm-printer"
#include "Mips.h"
#include "MipsSubtarget.h"
#include "MipsInstrInfo.h"
#include "MipsTargetMachine.h"
#include "MipsMachineFunction.h"
#include "llvm/BasicBlock.h"
#include "llvm/Instructions.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/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/Target/TargetRegistry.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
class MipsAsmPrinter : public AsmPrinter {
const MipsSubtarget *Subtarget;
public:
explicit MipsAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
: AsmPrinter(TM, Streamer) {
Subtarget = &TM.getSubtarget<MipsSubtarget>();
}
virtual const char *getPassName() const {
return "Mips Assembly Printer";
}
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 printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier = 0);
void printFCCOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier = 0);
void printSavedRegsBitmask(raw_ostream &O);
void printHex32(unsigned int Value, raw_ostream &O);
const char *getCurrentABIString() const;
void emitFrameDirective();
void printInstruction(const MachineInstr *MI,
raw_ostream &O); // autogen'd.
void EmitInstruction(const MachineInstr *MI) {
SmallString<128> Str;
raw_svector_ostream OS(Str);
printInstruction(MI, OS);
OutStreamer.EmitRawText(OS.str());
}
virtual void EmitFunctionBodyStart();
virtual void EmitFunctionBodyEnd();
virtual bool isBlockOnlyReachableByFallthrough(const MachineBasicBlock
*MBB) const;
static const char *getRegisterName(unsigned RegNo);
virtual void EmitFunctionEntryLabel();
void EmitStartOfAsmFile(Module &M);
};
} // end of anonymous namespace
#include "MipsGenAsmWriter.inc"
//===---------------------------------------------------------------------===//
//
// 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) {
const TargetFrameLowering *TFI = TM.getFrameLowering();
const TargetRegisterInfo *RI = TM.getRegisterInfo();
const MipsFunctionInfo *MipsFI = MF->getInfo<MipsFunctionInfo>();
// CPU and FPU Saved Registers Bitmasks
unsigned int CPUBitmask = 0;
unsigned int FPUBitmask = 0;
// Set the CPU and FPU 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 = MipsRegisterInfo::getRegisterNumbering(Reg);
if (Mips::CPURegsRegisterClass->contains(Reg))
CPUBitmask |= (1 << RegNum);
else
FPUBitmask |= (1 << RegNum);
}
// Return Address and Frame registers must also be set in CPUBitmask.
// FIXME: Do we really need hasFP() call here? When no FP is present SP is
// just returned -- will it be ok?
if (TFI->hasFP(*MF))
CPUBitmask |= (1 << MipsRegisterInfo::
getRegisterNumbering(RI->getFrameRegister(*MF)));
if (MFI->adjustsStack())
CPUBitmask |= (1 << MipsRegisterInfo::
getRegisterNumbering(RI->getRARegister()));
// Print CPUBitmask
O << "\t.mask \t"; printHex32(CPUBitmask, O);
O << ',' << MipsFI->getCPUTopSavedRegOff() << '\n';
// Print FPUBitmask
O << "\t.fmask\t"; printHex32(FPUBitmask, O); O << ","
<< MipsFI->getFPUTopSavedRegOff() << '\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 << utohexstr((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();
OutStreamer.EmitRawText("\t.frame\t$" +
Twine(LowercaseString(getRegisterName(stackReg))) +
"," + Twine(stackSize) + ",$" +
Twine(LowercaseString(getRegisterName(returnReg))));
}
/// Emit Set directives.
const char *MipsAsmPrinter::getCurrentABIString() const {
switch (Subtarget->getTargetABI()) {
case MipsSubtarget::O32: return "abi32";
case MipsSubtarget::O64: return "abiO64";
case MipsSubtarget::N32: return "abiN32";
case MipsSubtarget::N64: return "abi64";
case MipsSubtarget::EABI: return "eabi32"; // TODO: handle eabi64
default: break;
}
llvm_unreachable("Unknown Mips ABI");
return NULL;
}
void MipsAsmPrinter::EmitFunctionEntryLabel() {
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() {
emitFrameDirective();
SmallString<128> Str;
raw_svector_ostream OS(Str);
printSavedRegsBitmask(OS);
OutStreamer.EmitRawText(OS.str());
}
/// 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.
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)->getDesc().isTerminator()) ;
return !I->getDesc().isBarrier();
}
// Print out an operand for an inline asm expression.
bool MipsAsmPrinter::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 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;
}
switch (MO.getType()) {
case MachineOperand::MO_Register:
O << '$' << LowercaseString(getRegisterName(MO.getReg()));
break;
case MachineOperand::MO_Immediate:
O << (short int)MO.getImm();
break;
case MachineOperand::MO_MachineBasicBlock:
O << *MO.getMBB()->getSymbol();
return;
case MachineOperand::MO_GlobalAddress:
O << *Mang->getSymbol(MO.getGlobal());
break;
case MachineOperand::MO_BlockAddress: {
MCSymbol* BA = GetBlockAddressSymbol(MO.getBlockAddress());
O << BA->getName();
break;
}
case MachineOperand::MO_ExternalSymbol:
O << *GetExternalSymbolSymbol(MO.getSymbolName());
break;
case MachineOperand::MO_JumpTableIndex:
O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
<< '_' << MO.getIndex();
break;
case MachineOperand::MO_ConstantPoolIndex:
O << MAI->getPrivateGlobalPrefix() << "CPI"
<< getFunctionNumber() << "_" << MO.getIndex();
if (MO.getOffset())
O << "+" << MO.getOffset();
break;
default:
llvm_unreachable("<unknown operand type>");
}
if (closeP) O << ")";
}
void MipsAsmPrinter::printUnsignedImm(const MachineInstr *MI, int opNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(opNum);
if (MO.isImm())
O << (unsigned short int)MO.getImm();
else
printOperand(MI, opNum, O);
}
void MipsAsmPrinter::
printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
const char *Modifier) {
// when using stack locations for not load/store instructions
// print the same way as all normal 3 operand instructions.
if (Modifier && !strcmp(Modifier, "stackloc")) {
printOperand(MI, opNum+1, O);
O << ", ";
printOperand(MI, opNum, O);
return;
}
// Load/Store memory operands -- imm($reg)
// If PIC target the target is loaded as the
// pattern lw $25,%call16($28)
printOperand(MI, opNum, O);
O << "(";
printOperand(MI, opNum+1, O);
O << ")";
}
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
OutStreamer.EmitRawText("\t.section .mdebug." +
Twine(getCurrentABIString()));
// TODO: handle O64 ABI
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
OutStreamer.EmitRawText(StringRef("\t.previous"));
}
// Force static initialization.
extern "C" void LLVMInitializeMipsAsmPrinter() {
RegisterAsmPrinter<MipsAsmPrinter> X(TheMipsTarget);
RegisterAsmPrinter<MipsAsmPrinter> Y(TheMipselTarget);
}
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