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llvm-6502/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
Jack Carter 42faefc11d This patch moves from using a hard coded number (4) 
for the number of bytes in a particular instruction
to using
   const MCInstrDesc &Desc = MCII.get(TmpInst.getOpcode());
   Desc.getSize()

This is necessary with the advent of 16 bit instructions with
mips16 and micromips. It is also puts Mips in compliance with
the other targets for getting instruction size.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165171 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-03 21:58:54 +00:00

334 lines
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//===-- MipsMCCodeEmitter.cpp - Convert Mips Code to Machine Code ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the MipsMCCodeEmitter class.
//
//===----------------------------------------------------------------------===//
//
#define DEBUG_TYPE "mccodeemitter"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "MCTargetDesc/MipsDirectObjLower.h"
#include "MCTargetDesc/MipsFixupKinds.h"
#include "MCTargetDesc/MipsMCTargetDesc.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
class MipsMCCodeEmitter : public MCCodeEmitter {
MipsMCCodeEmitter(const MipsMCCodeEmitter &) LLVM_DELETED_FUNCTION;
void operator=(const MipsMCCodeEmitter &) LLVM_DELETED_FUNCTION;
const MCInstrInfo &MCII;
bool IsLittleEndian;
public:
MipsMCCodeEmitter(const MCInstrInfo &mcii, bool IsLittle) :
MCII(mcii), IsLittleEndian(IsLittle) {}
~MipsMCCodeEmitter() {}
void EmitByte(unsigned char C, raw_ostream &OS) const {
OS << (char)C;
}
void EmitInstruction(uint64_t Val, unsigned Size, raw_ostream &OS) const {
// Output the instruction encoding in little endian byte order.
for (unsigned i = 0; i < Size; ++i) {
unsigned Shift = IsLittleEndian ? i * 8 : (Size - 1 - i) * 8;
EmitByte((Val >> Shift) & 0xff, OS);
}
}
void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const;
// getBinaryCodeForInstr - TableGen'erated function for getting the
// binary encoding for an instruction.
uint64_t getBinaryCodeForInstr(const MCInst &MI,
SmallVectorImpl<MCFixup> &Fixups) const;
// getBranchJumpOpValue - Return binary encoding of the jump
// target operand. If the machine operand requires relocation,
// record the relocation and return zero.
unsigned getJumpTargetOpValue(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const;
// getBranchTargetOpValue - Return binary encoding of the branch
// target operand. If the machine operand requires relocation,
// record the relocation and return zero.
unsigned getBranchTargetOpValue(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const;
// getMachineOpValue - Return binary encoding of operand. If the machin
// operand requires relocation, record the relocation and return zero.
unsigned getMachineOpValue(const MCInst &MI,const MCOperand &MO,
SmallVectorImpl<MCFixup> &Fixups) const;
unsigned getMemEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const;
unsigned getSizeExtEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const;
unsigned getSizeInsEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const;
}; // class MipsMCCodeEmitter
} // namespace
MCCodeEmitter *llvm::createMipsMCCodeEmitterEB(const MCInstrInfo &MCII,
const MCRegisterInfo &MRI,
const MCSubtargetInfo &STI,
MCContext &Ctx)
{
return new MipsMCCodeEmitter(MCII, false);
}
MCCodeEmitter *llvm::createMipsMCCodeEmitterEL(const MCInstrInfo &MCII,
const MCRegisterInfo &MRI,
const MCSubtargetInfo &STI,
MCContext &Ctx)
{
return new MipsMCCodeEmitter(MCII, true);
}
/// EncodeInstruction - Emit the instruction.
/// Size the instruction (currently only 4 bytes
void MipsMCCodeEmitter::
EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const
{
// Non-pseudo instructions that get changed for direct object
// only based on operand values.
// If this list of instructions get much longer we will move
// the check to a function call. Until then, this is more efficient.
MCInst TmpInst = MI;
switch (MI.getOpcode()) {
// If shift amount is >= 32 it the inst needs to be lowered further
case Mips::DSLL:
case Mips::DSRL:
case Mips::DSRA:
Mips::LowerLargeShift(TmpInst);
break;
// Double extract instruction is chosen by pos and size operands
case Mips::DEXT:
case Mips::DINS:
Mips::LowerDextDins(TmpInst);
}
uint32_t Binary = getBinaryCodeForInstr(TmpInst, Fixups);
// Check for unimplemented opcodes.
// Unfortunately in MIPS both NOP and SLL will come in with Binary == 0
// so we have to special check for them.
unsigned Opcode = TmpInst.getOpcode();
if ((Opcode != Mips::NOP) && (Opcode != Mips::SLL) && !Binary)
llvm_unreachable("unimplemented opcode in EncodeInstruction()");
const MCInstrDesc &Desc = MCII.get(TmpInst.getOpcode());
uint64_t TSFlags = Desc.TSFlags;
// Pseudo instructions don't get encoded and shouldn't be here
// in the first place!
if ((TSFlags & MipsII::FormMask) == MipsII::Pseudo)
llvm_unreachable("Pseudo opcode found in EncodeInstruction()");
// Get byte count of instruction
unsigned Size = Desc.getSize();
if (!Size)
llvm_unreachable("Desc.getSize() returns 0");
EmitInstruction(Binary, Size, OS);
}
/// getBranchTargetOpValue - Return binary encoding of the branch
/// target operand. If the machine operand requires relocation,
/// record the relocation and return zero.
unsigned MipsMCCodeEmitter::
getBranchTargetOpValue(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
const MCOperand &MO = MI.getOperand(OpNo);
// If the destination is an immediate, we have nothing to do.
if (MO.isImm()) return MO.getImm();
assert(MO.isExpr() &&
"getBranchTargetOpValue expects only expressions or immediates");
const MCExpr *Expr = MO.getExpr();
Fixups.push_back(MCFixup::Create(0, Expr,
MCFixupKind(Mips::fixup_Mips_PC16)));
return 0;
}
/// getJumpTargetOpValue - Return binary encoding of the jump
/// target operand. If the machine operand requires relocation,
/// record the relocation and return zero.
unsigned MipsMCCodeEmitter::
getJumpTargetOpValue(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
const MCOperand &MO = MI.getOperand(OpNo);
// If the destination is an immediate, we have nothing to do.
if (MO.isImm()) return MO.getImm();
assert(MO.isExpr() &&
"getJumpTargetOpValue expects only expressions or an immediate");
const MCExpr *Expr = MO.getExpr();
Fixups.push_back(MCFixup::Create(0, Expr,
MCFixupKind(Mips::fixup_Mips_26)));
return 0;
}
/// getMachineOpValue - Return binary encoding of operand. If the machine
/// operand requires relocation, record the relocation and return zero.
unsigned MipsMCCodeEmitter::
getMachineOpValue(const MCInst &MI, const MCOperand &MO,
SmallVectorImpl<MCFixup> &Fixups) const {
if (MO.isReg()) {
unsigned Reg = MO.getReg();
unsigned RegNo = getMipsRegisterNumbering(Reg);
return RegNo;
} else if (MO.isImm()) {
return static_cast<unsigned>(MO.getImm());
} else if (MO.isFPImm()) {
return static_cast<unsigned>(APFloat(MO.getFPImm())
.bitcastToAPInt().getHiBits(32).getLimitedValue());
}
// MO must be an Expr.
assert(MO.isExpr());
const MCExpr *Expr = MO.getExpr();
MCExpr::ExprKind Kind = Expr->getKind();
if (Kind == MCExpr::Binary) {
Expr = static_cast<const MCBinaryExpr*>(Expr)->getLHS();
Kind = Expr->getKind();
}
assert (Kind == MCExpr::SymbolRef);
Mips::Fixups FixupKind = Mips::Fixups(0);
switch(cast<MCSymbolRefExpr>(Expr)->getKind()) {
default: llvm_unreachable("Unknown fixup kind!");
break;
case MCSymbolRefExpr::VK_Mips_GPOFF_HI :
FixupKind = Mips::fixup_Mips_GPOFF_HI;
break;
case MCSymbolRefExpr::VK_Mips_GPOFF_LO :
FixupKind = Mips::fixup_Mips_GPOFF_LO;
break;
case MCSymbolRefExpr::VK_Mips_GOT_PAGE :
FixupKind = Mips::fixup_Mips_GOT_PAGE;
break;
case MCSymbolRefExpr::VK_Mips_GOT_OFST :
FixupKind = Mips::fixup_Mips_GOT_OFST;
break;
case MCSymbolRefExpr::VK_Mips_GOT_DISP :
FixupKind = Mips::fixup_Mips_GOT_DISP;
break;
case MCSymbolRefExpr::VK_Mips_GPREL:
FixupKind = Mips::fixup_Mips_GPREL16;
break;
case MCSymbolRefExpr::VK_Mips_GOT_CALL:
FixupKind = Mips::fixup_Mips_CALL16;
break;
case MCSymbolRefExpr::VK_Mips_GOT16:
FixupKind = Mips::fixup_Mips_GOT_Global;
break;
case MCSymbolRefExpr::VK_Mips_GOT:
FixupKind = Mips::fixup_Mips_GOT_Local;
break;
case MCSymbolRefExpr::VK_Mips_ABS_HI:
FixupKind = Mips::fixup_Mips_HI16;
break;
case MCSymbolRefExpr::VK_Mips_ABS_LO:
FixupKind = Mips::fixup_Mips_LO16;
break;
case MCSymbolRefExpr::VK_Mips_TLSGD:
FixupKind = Mips::fixup_Mips_TLSGD;
break;
case MCSymbolRefExpr::VK_Mips_TLSLDM:
FixupKind = Mips::fixup_Mips_TLSLDM;
break;
case MCSymbolRefExpr::VK_Mips_DTPREL_HI:
FixupKind = Mips::fixup_Mips_DTPREL_HI;
break;
case MCSymbolRefExpr::VK_Mips_DTPREL_LO:
FixupKind = Mips::fixup_Mips_DTPREL_LO;
break;
case MCSymbolRefExpr::VK_Mips_GOTTPREL:
FixupKind = Mips::fixup_Mips_GOTTPREL;
break;
case MCSymbolRefExpr::VK_Mips_TPREL_HI:
FixupKind = Mips::fixup_Mips_TPREL_HI;
break;
case MCSymbolRefExpr::VK_Mips_TPREL_LO:
FixupKind = Mips::fixup_Mips_TPREL_LO;
break;
case MCSymbolRefExpr::VK_Mips_HIGHER:
FixupKind = Mips::fixup_Mips_HIGHER;
break;
case MCSymbolRefExpr::VK_Mips_HIGHEST:
FixupKind = Mips::fixup_Mips_HIGHEST;
break;
} // switch
Fixups.push_back(MCFixup::Create(0, MO.getExpr(), MCFixupKind(FixupKind)));
// All of the information is in the fixup.
return 0;
}
/// getMemEncoding - Return binary encoding of memory related operand.
/// If the offset operand requires relocation, record the relocation.
unsigned
MipsMCCodeEmitter::getMemEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
// Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
assert(MI.getOperand(OpNo).isReg());
unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo),Fixups) << 16;
unsigned OffBits = getMachineOpValue(MI, MI.getOperand(OpNo+1), Fixups);
return (OffBits & 0xFFFF) | RegBits;
}
unsigned
MipsMCCodeEmitter::getSizeExtEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
assert(MI.getOperand(OpNo).isImm());
unsigned SizeEncoding = getMachineOpValue(MI, MI.getOperand(OpNo), Fixups);
return SizeEncoding - 1;
}
// FIXME: should be called getMSBEncoding
//
unsigned
MipsMCCodeEmitter::getSizeInsEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
assert(MI.getOperand(OpNo-1).isImm());
assert(MI.getOperand(OpNo).isImm());
unsigned Position = getMachineOpValue(MI, MI.getOperand(OpNo-1), Fixups);
unsigned Size = getMachineOpValue(MI, MI.getOperand(OpNo), Fixups);
return Position + Size - 1;
}
#include "MipsGenMCCodeEmitter.inc"
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