diff options
Diffstat (limited to 'llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp')
| -rw-r--r-- | llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp new file mode 100644 index 000000000000..1a4c57e66d2f --- /dev/null +++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp @@ -0,0 +1,176 @@ +//=- WebAssemblyMCCodeEmitter.cpp - Convert WebAssembly code to machine code -// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// This file implements the WebAssemblyMCCodeEmitter class. +/// +//===----------------------------------------------------------------------===// + +#include "MCTargetDesc/WebAssemblyFixupKinds.h" +#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/Debug.h" +#include "llvm/Support/EndianStream.h" +#include "llvm/Support/LEB128.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 { + uint64_t Start = OS.tell(); + + uint64_t Binary = getBinaryCodeForInstr(MI, Fixups, STI); + if (Binary <= UINT8_MAX) { + OS << uint8_t(Binary); + } else { + assert(Binary <= UINT16_MAX && "Several-byte opcodes not supported yet"); + OS << uint8_t(Binary >> 8); + encodeULEB128(uint8_t(Binary), OS); + } + + // For br_table instructions, encode the size of the table. In the MCInst, + // there's an index operand (if not a stack instruction), one operand for + // each table entry, and the default operand. + if (MI.getOpcode() == WebAssembly::BR_TABLE_I32_S || + MI.getOpcode() == WebAssembly::BR_TABLE_I64_S) + encodeULEB128(MI.getNumOperands() - 1, OS); + if (MI.getOpcode() == WebAssembly::BR_TABLE_I32 || + MI.getOpcode() == WebAssembly::BR_TABLE_I64) + encodeULEB128(MI.getNumOperands() - 2, OS); + + const MCInstrDesc &Desc = MCII.get(MI.getOpcode()); + for (unsigned I = 0, E = MI.getNumOperands(); I < E; ++I) { + const MCOperand &MO = MI.getOperand(I); + if (MO.isReg()) { + /* nothing to encode */ + + } else if (MO.isImm()) { + if (I < Desc.getNumOperands()) { + const MCOperandInfo &Info = Desc.OpInfo[I]; + LLVM_DEBUG(dbgs() << "Encoding immediate: type=" + << int(Info.OperandType) << "\n"); + switch (Info.OperandType) { + case WebAssembly::OPERAND_I32IMM: + encodeSLEB128(int32_t(MO.getImm()), OS); + break; + case WebAssembly::OPERAND_OFFSET32: + encodeULEB128(uint32_t(MO.getImm()), OS); + break; + case WebAssembly::OPERAND_I64IMM: + encodeSLEB128(int64_t(MO.getImm()), OS); + break; + case WebAssembly::OPERAND_SIGNATURE: + OS << uint8_t(MO.getImm()); + break; + case WebAssembly::OPERAND_VEC_I8IMM: + support::endian::write<uint8_t>(OS, MO.getImm(), support::little); + break; + case WebAssembly::OPERAND_VEC_I16IMM: + support::endian::write<uint16_t>(OS, MO.getImm(), support::little); + break; + case WebAssembly::OPERAND_VEC_I32IMM: + support::endian::write<uint32_t>(OS, MO.getImm(), support::little); + break; + case WebAssembly::OPERAND_VEC_I64IMM: + support::endian::write<uint64_t>(OS, MO.getImm(), support::little); + break; + case WebAssembly::OPERAND_GLOBAL: + llvm_unreachable("wasm globals should only be accessed symbolicly"); + default: + encodeULEB128(uint64_t(MO.getImm()), OS); + } + } else { + encodeULEB128(uint64_t(MO.getImm()), OS); + } + + } else if (MO.isFPImm()) { + const MCOperandInfo &Info = Desc.OpInfo[I]; + if (Info.OperandType == WebAssembly::OPERAND_F32IMM) { + // TODO: MC converts all floating point immediate operands to double. + // This is fine for numeric values, but may cause NaNs to change bits. + auto F = float(MO.getFPImm()); + support::endian::write<float>(OS, F, support::little); + } else { + assert(Info.OperandType == WebAssembly::OPERAND_F64IMM); + double D = MO.getFPImm(); + support::endian::write<double>(OS, D, support::little); + } + + } else if (MO.isExpr()) { + const MCOperandInfo &Info = Desc.OpInfo[I]; + llvm::MCFixupKind FixupKind; + size_t PaddedSize = 5; + switch (Info.OperandType) { + case WebAssembly::OPERAND_I32IMM: + FixupKind = MCFixupKind(WebAssembly::fixup_sleb128_i32); + break; + case WebAssembly::OPERAND_I64IMM: + FixupKind = MCFixupKind(WebAssembly::fixup_sleb128_i64); + PaddedSize = 10; + break; + case WebAssembly::OPERAND_FUNCTION32: + case WebAssembly::OPERAND_OFFSET32: + case WebAssembly::OPERAND_SIGNATURE: + case WebAssembly::OPERAND_TYPEINDEX: + case WebAssembly::OPERAND_GLOBAL: + case WebAssembly::OPERAND_EVENT: + FixupKind = MCFixupKind(WebAssembly::fixup_uleb128_i32); + break; + default: + llvm_unreachable("unexpected symbolic operand kind"); + } + Fixups.push_back(MCFixup::create(OS.tell() - Start, MO.getExpr(), + FixupKind, MI.getLoc())); + ++MCNumFixups; + encodeULEB128(0, OS, PaddedSize); + } else { + llvm_unreachable("unexpected operand kind"); + } + } + + ++MCNumEmitted; // Keep track of the # of mi's emitted. +} + +#include "WebAssemblyGenMCCodeEmitter.inc" |