llvm-project/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCCodeEmitter.cpp

132 lines
4.9 KiB
C++

//===-- SystemZMCCodeEmitter.cpp - Convert SystemZ 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 SystemZMCCodeEmitter class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mccodeemitter"
#include "MCTargetDesc/SystemZMCTargetDesc.h"
#include "MCTargetDesc/SystemZMCFixups.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInstrInfo.h"
using namespace llvm;
namespace {
class SystemZMCCodeEmitter : public MCCodeEmitter {
const MCInstrInfo &MCII;
MCContext &Ctx;
public:
SystemZMCCodeEmitter(const MCInstrInfo &mcii, MCContext &ctx)
: MCII(mcii), Ctx(ctx) {
}
~SystemZMCCodeEmitter() {}
// OVerride MCCodeEmitter.
virtual void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const
LLVM_OVERRIDE;
private:
// Automatically generated by TableGen.
uint64_t getBinaryCodeForInstr(const MCInst &MI,
SmallVectorImpl<MCFixup> &Fixups) const;
// Called by the TableGen code to get the binary encoding of operand
// MO in MI. Fixups is the list of fixups against MI.
unsigned getMachineOpValue(const MCInst &MI, const MCOperand &MO,
SmallVectorImpl<MCFixup> &Fixups) const;
// Operand OpNum of MI needs a PC-relative fixup of kind Kind at
// Offset bytes from the start of MI. Add the fixup to Fixups
// and return the in-place addend, which since we're a RELA target
// is always 0.
unsigned getPCRelEncoding(const MCInst &MI, unsigned int OpNum,
SmallVectorImpl<MCFixup> &Fixups,
unsigned Kind, int64_t Offset) const;
unsigned getPC16DBLEncoding(const MCInst &MI, unsigned int OpNum,
SmallVectorImpl<MCFixup> &Fixups) const {
return getPCRelEncoding(MI, OpNum, Fixups, SystemZ::FK_390_PC16DBL, 2);
}
unsigned getPC32DBLEncoding(const MCInst &MI, unsigned int OpNum,
SmallVectorImpl<MCFixup> &Fixups) const {
return getPCRelEncoding(MI, OpNum, Fixups, SystemZ::FK_390_PC32DBL, 2);
}
unsigned getPLT16DBLEncoding(const MCInst &MI, unsigned int OpNum,
SmallVectorImpl<MCFixup> &Fixups) const {
return getPCRelEncoding(MI, OpNum, Fixups, SystemZ::FK_390_PLT16DBL, 2);
}
unsigned getPLT32DBLEncoding(const MCInst &MI, unsigned int OpNum,
SmallVectorImpl<MCFixup> &Fixups) const {
return getPCRelEncoding(MI, OpNum, Fixups, SystemZ::FK_390_PLT32DBL, 2);
}
};
}
MCCodeEmitter *llvm::createSystemZMCCodeEmitter(const MCInstrInfo &MCII,
const MCRegisterInfo &MRI,
const MCSubtargetInfo &MCSTI,
MCContext &Ctx) {
return new SystemZMCCodeEmitter(MCII, Ctx);
}
void SystemZMCCodeEmitter::
EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const {
uint64_t Bits = getBinaryCodeForInstr(MI, Fixups);
unsigned Size = MCII.get(MI.getOpcode()).getSize();
// Big-endian insertion of Size bytes.
unsigned ShiftValue = (Size * 8) - 8;
for (unsigned I = 0; I != Size; ++I) {
OS << uint8_t(Bits >> ShiftValue);
ShiftValue -= 8;
}
}
unsigned SystemZMCCodeEmitter::
getMachineOpValue(const MCInst &MI, const MCOperand &MO,
SmallVectorImpl<MCFixup> &Fixups) const {
if (MO.isReg())
return Ctx.getRegisterInfo().getEncodingValue(MO.getReg());
if (MO.isImm())
return static_cast<unsigned>(MO.getImm());
llvm_unreachable("Unexpected operand type!");
}
unsigned
SystemZMCCodeEmitter::getPCRelEncoding(const MCInst &MI, unsigned int OpNum,
SmallVectorImpl<MCFixup> &Fixups,
unsigned Kind, int64_t Offset) const {
const MCOperand &MO = MI.getOperand(OpNum);
// For compatibility with the GNU assembler, treat constant operands as
// unadjusted PC-relative offsets.
if (MO.isImm())
return MO.getImm() / 2;
const MCExpr *Expr = MO.getExpr();
if (Offset) {
// The operand value is relative to the start of MI, but the fixup
// is relative to the operand field itself, which is Offset bytes
// into MI. Add Offset to the relocation value to cancel out
// this difference.
const MCExpr *OffsetExpr = MCConstantExpr::Create(Offset, Ctx);
Expr = MCBinaryExpr::CreateAdd(Expr, OffsetExpr, Ctx);
}
Fixups.push_back(MCFixup::Create(Offset, Expr, (MCFixupKind)Kind));
return 0;
}
#include "SystemZGenMCCodeEmitter.inc"