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llvm-6502/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
Jack Carter da0860f78e [Mips] Support for unaligned load/store microMips instructions 
This includes instructions lwl, lwr, swl and swr.

Patch by Zoran Jovnovic


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188312 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-13 20:19:16 +00:00

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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/MipsFixupKinds.h"
#include "MCTargetDesc/MipsMCTargetDesc.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.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"
#define GET_INSTRMAP_INFO
#include "MipsGenInstrInfo.inc"
using namespace llvm;
namespace {
class MipsMCCodeEmitter : public MCCodeEmitter {
MipsMCCodeEmitter(const MipsMCCodeEmitter &) LLVM_DELETED_FUNCTION;
void operator=(const MipsMCCodeEmitter &) LLVM_DELETED_FUNCTION;
const MCInstrInfo &MCII;
MCContext &Ctx;
const MCSubtargetInfo &STI;
bool IsLittleEndian;
bool IsMicroMips;
public:
MipsMCCodeEmitter(const MCInstrInfo &mcii, MCContext &Ctx_,
const MCSubtargetInfo &sti, bool IsLittle) :
MCII(mcii), Ctx(Ctx_), STI (sti), IsLittleEndian(IsLittle) {
IsMicroMips = STI.getFeatureBits() & Mips::FeatureMicroMips;
}
~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.
// Little-endian byte ordering:
// mips32r2: 4 | 3 | 2 | 1
// microMIPS: 2 | 1 | 4 | 3
if (IsLittleEndian && Size == 4 && IsMicroMips) {
EmitInstruction(Val>>16, 2, OS);
EmitInstruction(Val, 2, OS);
} else {
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 getMemEncodingMMImm12(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;
unsigned
getExprOpValue(const MCExpr *Expr,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, Ctx, STI, false);
}
MCCodeEmitter *llvm::createMipsMCCodeEmitterEL(const MCInstrInfo &MCII,
const MCRegisterInfo &MRI,
const MCSubtargetInfo &STI,
MCContext &Ctx)
{
return new MipsMCCodeEmitter(MCII, Ctx, STI, true);
}
// If the D<shift> instruction has a shift amount that is greater
// than 31 (checked in calling routine), lower it to a D<shift>32 instruction
static void LowerLargeShift(MCInst& Inst) {
assert(Inst.getNumOperands() == 3 && "Invalid no. of operands for shift!");
assert(Inst.getOperand(2).isImm());
int64_t Shift = Inst.getOperand(2).getImm();
if (Shift <= 31)
return; // Do nothing
Shift -= 32;
// saminus32
Inst.getOperand(2).setImm(Shift);
switch (Inst.getOpcode()) {
default:
// Calling function is not synchronized
llvm_unreachable("Unexpected shift instruction");
case Mips::DSLL:
Inst.setOpcode(Mips::DSLL32);
return;
case Mips::DSRL:
Inst.setOpcode(Mips::DSRL32);
return;
case Mips::DSRA:
Inst.setOpcode(Mips::DSRA32);
return;
}
}
// Pick a DEXT or DINS instruction variant based on the pos and size operands
static void LowerDextDins(MCInst& InstIn) {
int Opcode = InstIn.getOpcode();
if (Opcode == Mips::DEXT)
assert(InstIn.getNumOperands() == 4 &&
"Invalid no. of machine operands for DEXT!");
else // Only DEXT and DINS are possible
assert(InstIn.getNumOperands() == 5 &&
"Invalid no. of machine operands for DINS!");
assert(InstIn.getOperand(2).isImm());
int64_t pos = InstIn.getOperand(2).getImm();
assert(InstIn.getOperand(3).isImm());
int64_t size = InstIn.getOperand(3).getImm();
if (size <= 32) {
if (pos < 32) // DEXT/DINS, do nothing
return;
// DEXTU/DINSU
InstIn.getOperand(2).setImm(pos - 32);
InstIn.setOpcode((Opcode == Mips::DEXT) ? Mips::DEXTU : Mips::DINSU);
return;
}
// DEXTM/DINSM
assert(pos < 32 && "DEXT/DINS cannot have both size and pos > 32");
InstIn.getOperand(3).setImm(size - 32);
InstIn.setOpcode((Opcode == Mips::DEXT) ? Mips::DEXTM : Mips::DINSM);
return;
}
/// 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:
LowerLargeShift(TmpInst);
break;
// Double extract instruction is chosen by pos and size operands
case Mips::DEXT:
case Mips::DINS:
LowerDextDins(TmpInst);
}
unsigned long N = Fixups.size();
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()");
if (STI.getFeatureBits() & Mips::FeatureMicroMips) {
int NewOpcode = Mips::Std2MicroMips (Opcode, Mips::Arch_micromips);
if (NewOpcode != -1) {
if (Fixups.size() > N)
Fixups.pop_back();
Opcode = NewOpcode;
TmpInst.setOpcode (NewOpcode);
Binary = getBinaryCodeForInstr(TmpInst, Fixups);
}
}
const MCInstrDesc &Desc = MCII.get(TmpInst.getOpcode());
// 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, divide by 4.
if (MO.isImm()) return MO.getImm() >> 2;
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, divide by 4.
if (MO.isImm()) return MO.getImm()>>2;
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;
}
unsigned MipsMCCodeEmitter::
getExprOpValue(const MCExpr *Expr,SmallVectorImpl<MCFixup> &Fixups) const {
int64_t Res;
if (Expr->EvaluateAsAbsolute(Res))
return Res;
MCExpr::ExprKind Kind = Expr->getKind();
if (Kind == MCExpr::Constant) {
return cast<MCConstantExpr>(Expr)->getValue();
}
if (Kind == MCExpr::Binary) {
unsigned Res = getExprOpValue(cast<MCBinaryExpr>(Expr)->getLHS(), Fixups);
Res += getExprOpValue(cast<MCBinaryExpr>(Expr)->getRHS(), Fixups);
return Res;
}
if (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;
case MCSymbolRefExpr::VK_Mips_GOT_HI16:
FixupKind = Mips::fixup_Mips_GOT_HI16;
break;
case MCSymbolRefExpr::VK_Mips_GOT_LO16:
FixupKind = Mips::fixup_Mips_GOT_LO16;
break;
case MCSymbolRefExpr::VK_Mips_CALL_HI16:
FixupKind = Mips::fixup_Mips_CALL_HI16;
break;
case MCSymbolRefExpr::VK_Mips_CALL_LO16:
FixupKind = Mips::fixup_Mips_CALL_LO16;
break;
} // switch
Fixups.push_back(MCFixup::Create(0, Expr, MCFixupKind(FixupKind)));
return 0;
}
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 = Ctx.getRegisterInfo()->getEncodingValue(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());
return getExprOpValue(MO.getExpr(),Fixups);
}
/// 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::
getMemEncodingMMImm12(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
// Base register is encoded in bits 20-16, offset is encoded in bits 11-0.
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 & 0x0FFF) | 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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