OSchip
/
llvm-project
mirror of https://github.com/THU-DSP-LAB/llvm-project.git
13
0
Fork 6
Code Issues Packages Projects Releases Wiki Activity
llvm-project/llvm/lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp

301 lines
10 KiB
C++
Raw Blame History

//==- WebAssemblyDisassembler.cpp - Disassembler for WebAssembly -*- C++ -*-==//
//
// 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 is part of the WebAssembly Disassembler.
///
/// It contains code to translate the data produced by the decoder into
/// MCInsts.
///
//===----------------------------------------------------------------------===//
#include "TargetInfo/WebAssemblyTargetInfo.h"
#include "Utils/WebAssemblyTypeUtilities.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDecoderOps.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/LEB128.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-disassembler"
using DecodeStatus = MCDisassembler::DecodeStatus;
#include "WebAssemblyGenDisassemblerTables.inc"
namespace {
static constexpr int WebAssemblyInstructionTableSize = 256;
class WebAssemblyDisassembler final : public MCDisassembler {
std::unique_ptr<const MCInstrInfo> MCII;
DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &CStream) const override;
Optional<DecodeStatus> onSymbolStart(SymbolInfoTy &Symbol, uint64_t &Size,
ArrayRef<uint8_t> Bytes,
uint64_t Address,
raw_ostream &CStream) const override;
public:
WebAssemblyDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx,
std::unique_ptr<const MCInstrInfo> MCII)
: MCDisassembler(STI, Ctx), MCII(std::move(MCII)) {}
};
} // end anonymous namespace
static MCDisassembler *createWebAssemblyDisassembler(const Target &T,
const MCSubtargetInfo &STI,
MCContext &Ctx) {
std::unique_ptr<const MCInstrInfo> MCII(T.createMCInstrInfo());
return new WebAssemblyDisassembler(STI, Ctx, std::move(MCII));
}
extern "C" LLVM_EXTERNAL_VISIBILITY void
LLVMInitializeWebAssemblyDisassembler() {
// Register the disassembler for each target.
TargetRegistry::RegisterMCDisassembler(getTheWebAssemblyTarget32(),
createWebAssemblyDisassembler);
TargetRegistry::RegisterMCDisassembler(getTheWebAssemblyTarget64(),
createWebAssemblyDisassembler);
}
static int nextByte(ArrayRef<uint8_t> Bytes, uint64_t &Size) {
if (Size >= Bytes.size())
return -1;
auto V = Bytes[Size];
Size++;
return V;
}
static bool nextLEB(int64_t &Val, ArrayRef<uint8_t> Bytes, uint64_t &Size,
bool Signed) {
unsigned N = 0;
const char *Error = nullptr;
Val = Signed ? decodeSLEB128(Bytes.data() + Size, &N,
Bytes.data() + Bytes.size(), &Error)
: static_cast<int64_t>(decodeULEB128(Bytes.data() + Size, &N,
Bytes.data() + Bytes.size(),
&Error));
if (Error)
return false;
Size += N;
return true;
}
static bool parseLEBImmediate(MCInst &MI, uint64_t &Size,
ArrayRef<uint8_t> Bytes, bool Signed) {
int64_t Val;
if (!nextLEB(Val, Bytes, Size, Signed))
return false;
MI.addOperand(MCOperand::createImm(Val));
return true;
}
template <typename T>
bool parseImmediate(MCInst &MI, uint64_t &Size, ArrayRef<uint8_t> Bytes) {
if (Size + sizeof(T) > Bytes.size())
return false;
T Val = support::endian::read<T, support::endianness::little, 1>(
Bytes.data() + Size);
Size += sizeof(T);
if (std::is_floating_point<T>::value) {
MI.addOperand(
MCOperand::createDFPImm(bit_cast<uint64_t>(static_cast<double>(Val))));
} else {
MI.addOperand(MCOperand::createImm(static_cast<int64_t>(Val)));
}
return true;
}
Optional<MCDisassembler::DecodeStatus> WebAssemblyDisassembler::onSymbolStart(
SymbolInfoTy &Symbol, uint64_t &Size, ArrayRef<uint8_t> Bytes,
uint64_t Address, raw_ostream &CStream) const {
Size = 0;
if (Address == 0) {
// Start of a code section: we're parsing only the function count.
int64_t FunctionCount;
if (!nextLEB(FunctionCount, Bytes, Size, false))
return None;
outs() << " # " << FunctionCount << " functions in section.";
} else {
// Parse the start of a single function.
int64_t BodySize, LocalEntryCount;
if (!nextLEB(BodySize, Bytes, Size, false) ||
!nextLEB(LocalEntryCount, Bytes, Size, false))
return None;
if (LocalEntryCount) {
outs() << " .local ";
for (int64_t I = 0; I < LocalEntryCount; I++) {
int64_t Count, Type;
if (!nextLEB(Count, Bytes, Size, false) ||
!nextLEB(Type, Bytes, Size, false))
return None;
for (int64_t J = 0; J < Count; J++) {
if (I || J)
outs() << ", ";
outs() << WebAssembly::anyTypeToString(Type);
}
}
}
}
outs() << "\n";
return MCDisassembler::Success;
}
MCDisassembler::DecodeStatus WebAssemblyDisassembler::getInstruction(
MCInst &MI, uint64_t &Size, ArrayRef<uint8_t> Bytes, uint64_t /*Address*/,
raw_ostream &CS) const {
CommentStream = &CS;
Size = 0;
int Opc = nextByte(Bytes, Size);
if (Opc < 0)
return MCDisassembler::Fail;
const auto *WasmInst = &InstructionTable0[Opc];
// If this is a prefix byte, indirect to another table.
if (WasmInst->ET == ET_Prefix) {
WasmInst = nullptr;
// Linear search, so far only 2 entries.
for (auto PT = PrefixTable; PT->Table; PT++) {
if (PT->Prefix == Opc) {
WasmInst = PT->Table;
break;
}
}
if (!WasmInst)
return MCDisassembler::Fail;
int64_t PrefixedOpc;
if (!nextLEB(PrefixedOpc, Bytes, Size, false))
return MCDisassembler::Fail;
if (PrefixedOpc < 0 || PrefixedOpc >= WebAssemblyInstructionTableSize)
return MCDisassembler::Fail;
WasmInst += PrefixedOpc;
}
if (WasmInst->ET == ET_Unused)
return MCDisassembler::Fail;
// At this point we must have a valid instruction to decode.
assert(WasmInst->ET == ET_Instruction);
MI.setOpcode(WasmInst->Opcode);
// Parse any operands.
for (uint8_t OPI = 0; OPI < WasmInst->NumOperands; OPI++) {
auto OT = OperandTable[WasmInst->OperandStart + OPI];
switch (OT) {
// ULEB operands:
case WebAssembly::OPERAND_BASIC_BLOCK:
case WebAssembly::OPERAND_LOCAL:
case WebAssembly::OPERAND_GLOBAL:
case WebAssembly::OPERAND_FUNCTION32:
case WebAssembly::OPERAND_TABLE:
case WebAssembly::OPERAND_OFFSET32:
case WebAssembly::OPERAND_OFFSET64:
case WebAssembly::OPERAND_P2ALIGN:
case WebAssembly::OPERAND_TYPEINDEX:
case WebAssembly::OPERAND_TAG:
case MCOI::OPERAND_IMMEDIATE: {
if (!parseLEBImmediate(MI, Size, Bytes, false))
return MCDisassembler::Fail;
break;
}
// SLEB operands:
case WebAssembly::OPERAND_I32IMM:
case WebAssembly::OPERAND_I64IMM: {
if (!parseLEBImmediate(MI, Size, Bytes, true))
return MCDisassembler::Fail;
break;
}
// block_type operands:
case WebAssembly::OPERAND_SIGNATURE: {
int64_t Val;
uint64_t PrevSize = Size;
if (!nextLEB(Val, Bytes, Size, true))
return MCDisassembler::Fail;
if (Val < 0) {
// Negative values are single septet value types or empty types
if (Size != PrevSize + 1) {
MI.addOperand(
MCOperand::createImm(int64_t(WebAssembly::BlockType::Invalid)));
} else {
MI.addOperand(MCOperand::createImm(Val & 0x7f));
}
} else {
// We don't have access to the signature, so create a symbol without one
MCSymbol *Sym = getContext().createTempSymbol("typeindex", true);
auto *WasmSym = cast<MCSymbolWasm>(Sym);
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
const MCExpr *Expr = MCSymbolRefExpr::create(
WasmSym, MCSymbolRefExpr::VK_WASM_TYPEINDEX, getContext());
MI.addOperand(MCOperand::createExpr(Expr));
}
break;
}
// FP operands.
case WebAssembly::OPERAND_F32IMM: {
if (!parseImmediate<float>(MI, Size, Bytes))
return MCDisassembler::Fail;
break;
}
case WebAssembly::OPERAND_F64IMM: {
if (!parseImmediate<double>(MI, Size, Bytes))
return MCDisassembler::Fail;
break;
}
// Vector lane operands (not LEB encoded).
case WebAssembly::OPERAND_VEC_I8IMM: {
if (!parseImmediate<uint8_t>(MI, Size, Bytes))
return MCDisassembler::Fail;
break;
}
case WebAssembly::OPERAND_VEC_I16IMM: {
if (!parseImmediate<uint16_t>(MI, Size, Bytes))
return MCDisassembler::Fail;
break;
}
case WebAssembly::OPERAND_VEC_I32IMM: {
if (!parseImmediate<uint32_t>(MI, Size, Bytes))
return MCDisassembler::Fail;
break;
}
case WebAssembly::OPERAND_VEC_I64IMM: {
if (!parseImmediate<uint64_t>(MI, Size, Bytes))
return MCDisassembler::Fail;
break;
}
case WebAssembly::OPERAND_BRLIST: {
int64_t TargetTableLen;
if (!nextLEB(TargetTableLen, Bytes, Size, false))
return MCDisassembler::Fail;
for (int64_t I = 0; I < TargetTableLen; I++) {
if (!parseLEBImmediate(MI, Size, Bytes, false))
return MCDisassembler::Fail;
}
// Default case.
if (!parseLEBImmediate(MI, Size, Bytes, false))
return MCDisassembler::Fail;
break;
}
case MCOI::OPERAND_REGISTER:
// The tablegen header currently does not have any register operands since
// we use only the stack (_S) instructions.
// If you hit this that probably means a bad instruction definition in
// tablegen.
llvm_unreachable("Register operand in WebAssemblyDisassembler");
default:
llvm_unreachable("Unknown operand type in WebAssemblyDisassembler");
}
}
return MCDisassembler::Success;
}
Reference in New Issue View Git Blame Copy Permalink