3acb187d95
This changes locals from being declared by the emitLocal hook in WebAssemblyTargetStreamer, rather than with an instruction. After exploring the infastructure in LLVM more, this seems to make more sense since declaring locals doesn't use an encoded opcode. This also adds more 0xd opcodes, type encodings, and miscellaneous binary encoding bits. llvm-svn: 285040
122 lines
4.5 KiB
C++
122 lines
4.5 KiB
C++
//=- WebAssemblyMCCodeEmitter.cpp - Convert WebAssembly code to machine code -//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief This file implements the WebAssemblyMCCodeEmitter class.
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///
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/MC/MCCodeEmitter.h"
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#include "llvm/MC/MCFixup.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/MC/MCInstrInfo.h"
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#include "llvm/MC/MCRegisterInfo.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Support/EndianStream.h"
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#include "llvm/Support/LEB128.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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#define DEBUG_TYPE "mccodeemitter"
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STATISTIC(MCNumEmitted, "Number of MC instructions emitted.");
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STATISTIC(MCNumFixups, "Number of MC fixups created.");
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namespace {
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class WebAssemblyMCCodeEmitter final : public MCCodeEmitter {
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const MCInstrInfo &MCII;
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// Implementation generated by tablegen.
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uint64_t getBinaryCodeForInstr(const MCInst &MI,
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SmallVectorImpl<MCFixup> &Fixups,
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const MCSubtargetInfo &STI) const;
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void encodeInstruction(const MCInst &MI, raw_ostream &OS,
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SmallVectorImpl<MCFixup> &Fixups,
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const MCSubtargetInfo &STI) const override;
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public:
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WebAssemblyMCCodeEmitter(const MCInstrInfo &mcii) : MCII(mcii) {}
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};
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} // end anonymous namespace
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MCCodeEmitter *llvm::createWebAssemblyMCCodeEmitter(const MCInstrInfo &MCII) {
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return new WebAssemblyMCCodeEmitter(MCII);
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}
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void WebAssemblyMCCodeEmitter::encodeInstruction(
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const MCInst &MI, raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups,
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const MCSubtargetInfo &STI) const {
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uint64_t Start = OS.tell();
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uint64_t Binary = getBinaryCodeForInstr(MI, Fixups, STI);
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assert(Binary < UINT8_MAX && "Multi-byte opcodes not supported yet");
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OS << uint8_t(Binary);
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const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
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for (unsigned i = 0, e = MI.getNumOperands(); i < e; ++i) {
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const MCOperand &MO = MI.getOperand(i);
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if (MO.isReg()) {
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/* nothing to encode */
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} else if (MO.isImm()) {
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if (i < Desc.getNumOperands()) {
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assert(Desc.TSFlags == 0 &&
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"WebAssembly non-variable_ops don't use TSFlags");
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const MCOperandInfo &Info = Desc.OpInfo[i];
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if (Info.OperandType == WebAssembly::OPERAND_I32IMM) {
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encodeSLEB128(int32_t(MO.getImm()), OS);
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} else if (Info.OperandType == WebAssembly::OPERAND_I64IMM) {
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encodeSLEB128(int64_t(MO.getImm()), OS);
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} else {
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encodeULEB128(uint64_t(MO.getImm()), OS);
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}
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} else {
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assert(Desc.TSFlags == (WebAssemblyII::VariableOpIsImmediate |
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WebAssemblyII::VariableOpImmediateIsLabel));
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encodeULEB128(uint64_t(MO.getImm()), OS);
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}
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} else if (MO.isFPImm()) {
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assert(i < Desc.getNumOperands() &&
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"Unexpected floating-point immediate as a non-fixed operand");
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assert(Desc.TSFlags == 0 &&
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"WebAssembly variable_ops floating point ops don't use TSFlags");
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const MCOperandInfo &Info = Desc.OpInfo[i];
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if (Info.OperandType == WebAssembly::OPERAND_F32IMM) {
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// TODO: MC converts all floating point immediate operands to double.
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// This is fine for numeric values, but may cause NaNs to change bits.
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float f = float(MO.getFPImm());
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support::endian::Writer<support::little>(OS).write<float>(f);
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} else {
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assert(Info.OperandType == WebAssembly::OPERAND_F64IMM);
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double d = MO.getFPImm();
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support::endian::Writer<support::little>(OS).write<double>(d);
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}
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} else if (MO.isExpr()) {
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Fixups.push_back(MCFixup::create(
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OS.tell() - Start, MO.getExpr(),
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STI.getTargetTriple().isArch64Bit() ? FK_Data_8 : FK_Data_4,
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MI.getLoc()));
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++MCNumFixups;
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encodeULEB128(STI.getTargetTriple().isArch64Bit() ? UINT64_MAX
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: uint64_t(UINT32_MAX),
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OS);
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} else {
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llvm_unreachable("unexpected operand kind");
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}
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}
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++MCNumEmitted; // Keep track of the # of mi's emitted.
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}
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#include "WebAssemblyGenMCCodeEmitter.inc"
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