llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp

91 lines
3.3 KiB
C++

//=- WebAssemblyMCCodeEmitter.cpp - Convert WebAssembly 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.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file implements the WebAssemblyMCCodeEmitter class.
///
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "mccodeemitter"
STATISTIC(MCNumEmitted, "Number of MC instructions emitted.");
STATISTIC(MCNumFixups, "Number of MC fixups created.");
namespace {
class WebAssemblyMCCodeEmitter final : public MCCodeEmitter {
const MCInstrInfo &MCII;
// Implementation generated by tablegen.
uint64_t getBinaryCodeForInstr(const MCInst &MI,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const;
void encodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const override;
public:
WebAssemblyMCCodeEmitter(const MCInstrInfo &mcii) : MCII(mcii) {}
};
} // end anonymous namespace
MCCodeEmitter *llvm::createWebAssemblyMCCodeEmitter(const MCInstrInfo &MCII) {
return new WebAssemblyMCCodeEmitter(MCII);
}
void WebAssemblyMCCodeEmitter::encodeInstruction(
const MCInst &MI, raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
// FIXME: This is not the real binary encoding. This is an extremely
// over-simplified encoding where we just use uint64_t for everything. This
// is a temporary measure.
support::endian::Writer<support::little>(OS).write<uint64_t>(MI.getOpcode());
const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
if (Desc.isVariadic())
support::endian::Writer<support::little>(OS).write<uint64_t>(
MI.getNumOperands() - Desc.NumOperands);
for (unsigned i = 0, e = MI.getNumOperands(); i < e; ++i) {
const MCOperand &MO = MI.getOperand(i);
if (MO.isReg()) {
support::endian::Writer<support::little>(OS).write<uint64_t>(MO.getReg());
} else if (MO.isImm()) {
support::endian::Writer<support::little>(OS).write<uint64_t>(MO.getImm());
} else if (MO.isFPImm()) {
support::endian::Writer<support::little>(OS).write<double>(MO.getFPImm());
} else if (MO.isExpr()) {
support::endian::Writer<support::little>(OS).write<uint64_t>(0);
Fixups.push_back(MCFixup::create(
(1 + MCII.get(MI.getOpcode()).isVariadic() + i) * sizeof(uint64_t),
MO.getExpr(),
STI.getTargetTriple().isArch64Bit() ? FK_Data_8 : FK_Data_4,
MI.getLoc()));
++MCNumFixups;
} else {
llvm_unreachable("unexpected operand kind");
}
}
++MCNumEmitted; // Keep track of the # of mi's emitted.
}
#include "WebAssemblyGenMCCodeEmitter.inc"