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diff --git a/js/src/wasm/WasmBinary.h b/js/src/wasm/WasmBinary.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ *
+ * Copyright 2021 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef wasm_binary_h
+#define wasm_binary_h
+
+#include "mozilla/DebugOnly.h"
+#include "mozilla/Maybe.h"
+
+#include <type_traits>
+
+#include "js/WasmFeatures.h"
+
+#include "wasm/WasmCompile.h"
+#include "wasm/WasmCompileArgs.h"
+#include "wasm/WasmConstants.h"
+#include "wasm/WasmTypeDecls.h"
+#include "wasm/WasmTypeDef.h"
+#include "wasm/WasmValType.h"
+
+namespace js {
+namespace wasm {
+
+using mozilla::DebugOnly;
+using mozilla::Maybe;
+
+struct ModuleEnvironment;
+
+// The Opcode compactly and safely represents the primary opcode plus any
+// extension, with convenient predicates and accessors.
+
+class Opcode {
+ uint32_t bits_;
+
+ public:
+ MOZ_IMPLICIT Opcode(Op op) : bits_(uint32_t(op)) {
+ static_assert(size_t(Op::Limit) == 256, "fits");
+ MOZ_ASSERT(size_t(op) < size_t(Op::Limit));
+ }
+ MOZ_IMPLICIT Opcode(MiscOp op)
+ : bits_((uint32_t(op) << 8) | uint32_t(Op::MiscPrefix)) {
+ static_assert(size_t(MiscOp::Limit) <= 0xFFFFFF, "fits");
+ MOZ_ASSERT(size_t(op) < size_t(MiscOp::Limit));
+ }
+ MOZ_IMPLICIT Opcode(ThreadOp op)
+ : bits_((uint32_t(op) << 8) | uint32_t(Op::ThreadPrefix)) {
+ static_assert(size_t(ThreadOp::Limit) <= 0xFFFFFF, "fits");
+ MOZ_ASSERT(size_t(op) < size_t(ThreadOp::Limit));
+ }
+ MOZ_IMPLICIT Opcode(MozOp op)
+ : bits_((uint32_t(op) << 8) | uint32_t(Op::MozPrefix)) {
+ static_assert(size_t(MozOp::Limit) <= 0xFFFFFF, "fits");
+ MOZ_ASSERT(size_t(op) < size_t(MozOp::Limit));
+ }
+ MOZ_IMPLICIT Opcode(SimdOp op)
+ : bits_((uint32_t(op) << 8) | uint32_t(Op::SimdPrefix)) {
+ static_assert(size_t(SimdOp::Limit) <= 0xFFFFFF, "fits");
+ MOZ_ASSERT(size_t(op) < size_t(SimdOp::Limit));
+ }
+
+ bool isOp() const { return bits_ < uint32_t(Op::FirstPrefix); }
+ bool isMisc() const { return (bits_ & 255) == uint32_t(Op::MiscPrefix); }
+ bool isThread() const { return (bits_ & 255) == uint32_t(Op::ThreadPrefix); }
+ bool isMoz() const { return (bits_ & 255) == uint32_t(Op::MozPrefix); }
+ bool isSimd() const { return (bits_ & 255) == uint32_t(Op::SimdPrefix); }
+
+ Op asOp() const {
+ MOZ_ASSERT(isOp());
+ return Op(bits_);
+ }
+ MiscOp asMisc() const {
+ MOZ_ASSERT(isMisc());
+ return MiscOp(bits_ >> 8);
+ }
+ ThreadOp asThread() const {
+ MOZ_ASSERT(isThread());
+ return ThreadOp(bits_ >> 8);
+ }
+ MozOp asMoz() const {
+ MOZ_ASSERT(isMoz());
+ return MozOp(bits_ >> 8);
+ }
+ SimdOp asSimd() const {
+ MOZ_ASSERT(isSimd());
+ return SimdOp(bits_ >> 8);
+ }
+
+ uint32_t bits() const { return bits_; }
+
+ bool operator==(const Opcode& that) const { return bits_ == that.bits_; }
+ bool operator!=(const Opcode& that) const { return bits_ != that.bits_; }
+};
+
+// This struct captures the bytecode offset of a section's payload (so not
+// including the header) and the size of the payload.
+
+struct SectionRange {
+ uint32_t start;
+ uint32_t size;
+
+ uint32_t end() const { return start + size; }
+ bool operator==(const SectionRange& rhs) const {
+ return start == rhs.start && size == rhs.size;
+ }
+};
+
+using MaybeSectionRange = Maybe<SectionRange>;
+
+// The Encoder class appends bytes to the Bytes object it is given during
+// construction. The client is responsible for the Bytes's lifetime and must
+// keep the Bytes alive as long as the Encoder is used.
+
+class Encoder {
+ Bytes& bytes_;
+
+ template <class T>
+ [[nodiscard]] bool write(const T& v) {
+ return bytes_.append(reinterpret_cast<const uint8_t*>(&v), sizeof(T));
+ }
+
+ template <typename UInt>
+ [[nodiscard]] bool writeVarU(UInt i) {
+ do {
+ uint8_t byte = i & 0x7f;
+ i >>= 7;
+ if (i != 0) {
+ byte |= 0x80;
+ }
+ if (!bytes_.append(byte)) {
+ return false;
+ }
+ } while (i != 0);
+ return true;
+ }
+
+ template <typename SInt>
+ [[nodiscard]] bool writeVarS(SInt i) {
+ bool done;
+ do {
+ uint8_t byte = i & 0x7f;
+ i >>= 7;
+ done = ((i == 0) && !(byte & 0x40)) || ((i == -1) && (byte & 0x40));
+ if (!done) {
+ byte |= 0x80;
+ }
+ if (!bytes_.append(byte)) {
+ return false;
+ }
+ } while (!done);
+ return true;
+ }
+
+ void patchVarU32(size_t offset, uint32_t patchBits, uint32_t assertBits) {
+ do {
+ uint8_t assertByte = assertBits & 0x7f;
+ uint8_t patchByte = patchBits & 0x7f;
+ assertBits >>= 7;
+ patchBits >>= 7;
+ if (assertBits != 0) {
+ assertByte |= 0x80;
+ patchByte |= 0x80;
+ }
+ MOZ_ASSERT(assertByte == bytes_[offset]);
+ (void)assertByte;
+ bytes_[offset] = patchByte;
+ offset++;
+ } while (assertBits != 0);
+ }
+
+ void patchFixedU7(size_t offset, uint8_t patchBits, uint8_t assertBits) {
+ MOZ_ASSERT(patchBits <= uint8_t(INT8_MAX));
+ patchFixedU8(offset, patchBits, assertBits);
+ }
+
+ void patchFixedU8(size_t offset, uint8_t patchBits, uint8_t assertBits) {
+ MOZ_ASSERT(bytes_[offset] == assertBits);
+ bytes_[offset] = patchBits;
+ }
+
+ uint32_t varU32ByteLength(size_t offset) const {
+ size_t start = offset;
+ while (bytes_[offset] & 0x80) {
+ offset++;
+ }
+ return offset - start + 1;
+ }
+
+ public:
+ explicit Encoder(Bytes& bytes) : bytes_(bytes) { MOZ_ASSERT(empty()); }
+
+ size_t currentOffset() const { return bytes_.length(); }
+ bool empty() const { return currentOffset() == 0; }
+
+ // Fixed-size encoding operations simply copy the literal bytes (without
+ // attempting to align).
+
+ [[nodiscard]] bool writeFixedU7(uint8_t i) {
+ MOZ_ASSERT(i <= uint8_t(INT8_MAX));
+ return writeFixedU8(i);
+ }
+ [[nodiscard]] bool writeFixedU8(uint8_t i) { return write<uint8_t>(i); }
+ [[nodiscard]] bool writeFixedU32(uint32_t i) { return write<uint32_t>(i); }
+ [[nodiscard]] bool writeFixedF32(float f) { return write<float>(f); }
+ [[nodiscard]] bool writeFixedF64(double d) { return write<double>(d); }
+
+ // Variable-length encodings that all use LEB128.
+
+ [[nodiscard]] bool writeVarU32(uint32_t i) { return writeVarU<uint32_t>(i); }
+ [[nodiscard]] bool writeVarS32(int32_t i) { return writeVarS<int32_t>(i); }
+ [[nodiscard]] bool writeVarU64(uint64_t i) { return writeVarU<uint64_t>(i); }
+ [[nodiscard]] bool writeVarS64(int64_t i) { return writeVarS<int64_t>(i); }
+ [[nodiscard]] bool writeValType(ValType type) {
+ static_assert(size_t(TypeCode::Limit) <= UINT8_MAX, "fits");
+ // writeValType is only used by asm.js, which doesn't use type
+ // references
+ MOZ_RELEASE_ASSERT(!type.isTypeRef(), "NYI");
+ TypeCode tc = type.packed().typeCode();
+ MOZ_ASSERT(size_t(tc) < size_t(TypeCode::Limit));
+ return writeFixedU8(uint8_t(tc));
+ }
+ [[nodiscard]] bool writeOp(Opcode opcode) {
+ // The Opcode constructor has asserted that `opcode` is meaningful, so no
+ // further correctness checking is necessary here.
+ uint32_t bits = opcode.bits();
+ if (!writeFixedU8(bits & 255)) {
+ return false;
+ }
+ if (opcode.isOp()) {
+ return true;
+ }
+ return writeVarU32(bits >> 8);
+ }
+
+ // Fixed-length encodings that allow back-patching.
+
+ [[nodiscard]] bool writePatchableFixedU7(size_t* offset) {
+ *offset = bytes_.length();
+ return writeFixedU8(UINT8_MAX);
+ }
+ void patchFixedU7(size_t offset, uint8_t patchBits) {
+ return patchFixedU7(offset, patchBits, UINT8_MAX);
+ }
+
+ // Variable-length encodings that allow back-patching.
+
+ [[nodiscard]] bool writePatchableVarU32(size_t* offset) {
+ *offset = bytes_.length();
+ return writeVarU32(UINT32_MAX);
+ }
+ void patchVarU32(size_t offset, uint32_t patchBits) {
+ return patchVarU32(offset, patchBits, UINT32_MAX);
+ }
+
+ // Byte ranges start with an LEB128 length followed by an arbitrary sequence
+ // of bytes. When used for strings, bytes are to be interpreted as utf8.
+
+ [[nodiscard]] bool writeBytes(const void* bytes, uint32_t numBytes) {
+ return writeVarU32(numBytes) &&
+ bytes_.append(reinterpret_cast<const uint8_t*>(bytes), numBytes);
+ }
+
+ // A "section" is a contiguous range of bytes that stores its own size so
+ // that it may be trivially skipped without examining the payload. Sections
+ // require backpatching since the size of the section is only known at the
+ // end while the size's varU32 must be stored at the beginning. Immediately
+ // after the section length is the string id of the section.
+
+ [[nodiscard]] bool startSection(SectionId id, size_t* offset) {
+ MOZ_ASSERT(uint32_t(id) < 128);
+ return writeVarU32(uint32_t(id)) && writePatchableVarU32(offset);
+ }
+ void finishSection(size_t offset) {
+ return patchVarU32(offset,
+ bytes_.length() - offset - varU32ByteLength(offset));
+ }
+};
+
+// The Decoder class decodes the bytes in the range it is given during
+// construction. The client is responsible for keeping the byte range alive as
+// long as the Decoder is used.
+
+class Decoder {
+ const uint8_t* const beg_;
+ const uint8_t* const end_;
+ const uint8_t* cur_;
+ const size_t offsetInModule_;
+ UniqueChars* error_;
+ UniqueCharsVector* warnings_;
+ bool resilientMode_;
+
+ template <class T>
+ [[nodiscard]] bool read(T* out) {
+ if (bytesRemain() < sizeof(T)) {
+ return false;
+ }
+ memcpy((void*)out, cur_, sizeof(T));
+ cur_ += sizeof(T);
+ return true;
+ }
+
+ template <class T>
+ T uncheckedRead() {
+ MOZ_ASSERT(bytesRemain() >= sizeof(T));
+ T ret;
+ memcpy(&ret, cur_, sizeof(T));
+ cur_ += sizeof(T);
+ return ret;
+ }
+
+ template <class T>
+ void uncheckedRead(T* ret) {
+ MOZ_ASSERT(bytesRemain() >= sizeof(T));
+ memcpy(ret, cur_, sizeof(T));
+ cur_ += sizeof(T);
+ }
+
+ template <typename UInt>
+ [[nodiscard]] bool readVarU(UInt* out) {
+ DebugOnly<const uint8_t*> before = cur_;
+ const unsigned numBits = sizeof(UInt) * CHAR_BIT;
+ const unsigned remainderBits = numBits % 7;
+ const unsigned numBitsInSevens = numBits - remainderBits;
+ UInt u = 0;
+ uint8_t byte;
+ UInt shift = 0;
+ do {
+ if (!readFixedU8(&byte)) {
+ return false;
+ }
+ if (!(byte & 0x80)) {
+ *out = u | UInt(byte) << shift;
+ return true;
+ }
+ u |= UInt(byte & 0x7F) << shift;
+ shift += 7;
+ } while (shift != numBitsInSevens);
+ if (!readFixedU8(&byte) || (byte & (unsigned(-1) << remainderBits))) {
+ return false;
+ }
+ *out = u | (UInt(byte) << numBitsInSevens);
+ MOZ_ASSERT_IF(sizeof(UInt) == 4,
+ unsigned(cur_ - before) <= MaxVarU32DecodedBytes);
+ return true;
+ }
+
+ template <typename SInt>
+ [[nodiscard]] bool readVarS(SInt* out) {
+ using UInt = std::make_unsigned_t<SInt>;
+ const unsigned numBits = sizeof(SInt) * CHAR_BIT;
+ const unsigned remainderBits = numBits % 7;
+ const unsigned numBitsInSevens = numBits - remainderBits;
+ SInt s = 0;
+ uint8_t byte;
+ unsigned shift = 0;
+ do {
+ if (!readFixedU8(&byte)) {
+ return false;
+ }
+ s |= SInt(byte & 0x7f) << shift;
+ shift += 7;
+ if (!(byte & 0x80)) {
+ if (byte & 0x40) {
+ s |= UInt(-1) << shift;
+ }
+ *out = s;
+ return true;
+ }
+ } while (shift < numBitsInSevens);
+ if (!remainderBits || !readFixedU8(&byte) || (byte & 0x80)) {
+ return false;
+ }
+ uint8_t mask = 0x7f & (uint8_t(-1) << remainderBits);
+ if ((byte & mask) != ((byte & (1 << (remainderBits - 1))) ? mask : 0)) {
+ return false;
+ }
+ *out = s | UInt(byte) << shift;
+ return true;
+ }
+
+ public:
+ Decoder(const uint8_t* begin, const uint8_t* end, size_t offsetInModule,
+ UniqueChars* error, UniqueCharsVector* warnings = nullptr,
+ bool resilientMode = false)
+ : beg_(begin),
+ end_(end),
+ cur_(begin),
+ offsetInModule_(offsetInModule),
+ error_(error),
+ warnings_(warnings),
+ resilientMode_(resilientMode) {
+ MOZ_ASSERT(begin <= end);
+ }
+ explicit Decoder(const Bytes& bytes, size_t offsetInModule = 0,
+ UniqueChars* error = nullptr,
+ UniqueCharsVector* warnings = nullptr)
+ : beg_(bytes.begin()),
+ end_(bytes.end()),
+ cur_(bytes.begin()),
+ offsetInModule_(offsetInModule),
+ error_(error),
+ warnings_(warnings),
+ resilientMode_(false) {}
+
+ // These convenience functions use currentOffset() as the errorOffset.
+ bool fail(const char* msg) { return fail(currentOffset(), msg); }
+ bool failf(const char* msg, ...) MOZ_FORMAT_PRINTF(2, 3);
+ void warnf(const char* msg, ...) MOZ_FORMAT_PRINTF(2, 3);
+
+ // Report an error at the given offset (relative to the whole module).
+ bool fail(size_t errorOffset, const char* msg);
+
+ UniqueChars* error() { return error_; }
+
+ void clearError() {
+ if (error_) {
+ error_->reset();
+ }
+ }
+
+ bool done() const {
+ MOZ_ASSERT(cur_ <= end_);
+ return cur_ == end_;
+ }
+ bool resilientMode() const { return resilientMode_; }
+
+ size_t bytesRemain() const {
+ MOZ_ASSERT(end_ >= cur_);
+ return size_t(end_ - cur_);
+ }
+ // pos must be a value previously returned from currentPosition.
+ void rollbackPosition(const uint8_t* pos) { cur_ = pos; }
+ const uint8_t* currentPosition() const { return cur_; }
+ size_t beginOffset() const { return offsetInModule_; }
+ size_t currentOffset() const { return offsetInModule_ + (cur_ - beg_); }
+ const uint8_t* begin() const { return beg_; }
+ const uint8_t* end() const { return end_; }
+
+ // Peek at the next byte, if it exists, without advancing the position.
+
+ bool peekByte(uint8_t* byte) {
+ if (done()) {
+ return false;
+ }
+ *byte = *cur_;
+ return true;
+ }
+
+ // Fixed-size encoding operations simply copy the literal bytes (without
+ // attempting to align).
+
+ [[nodiscard]] bool readFixedU8(uint8_t* i) { return read<uint8_t>(i); }
+ [[nodiscard]] bool readFixedU32(uint32_t* u) { return read<uint32_t>(u); }
+ [[nodiscard]] bool readFixedF32(float* f) { return read<float>(f); }
+ [[nodiscard]] bool readFixedF64(double* d) { return read<double>(d); }
+#ifdef ENABLE_WASM_SIMD
+ [[nodiscard]] bool readFixedV128(V128* d) {
+ for (unsigned i = 0; i < 16; i++) {
+ if (!read<uint8_t>(d->bytes + i)) {
+ return false;
+ }
+ }
+ return true;
+ }
+#endif
+
+ // Variable-length encodings that all use LEB128.
+
+ [[nodiscard]] bool readVarU32(uint32_t* out) {
+ return readVarU<uint32_t>(out);
+ }
+ [[nodiscard]] bool readVarS32(int32_t* out) { return readVarS<int32_t>(out); }
+ [[nodiscard]] bool readVarU64(uint64_t* out) {
+ return readVarU<uint64_t>(out);
+ }
+ [[nodiscard]] bool readVarS64(int64_t* out) { return readVarS<int64_t>(out); }
+
+ // Value and reference types
+
+ [[nodiscard]] ValType uncheckedReadValType(const TypeContext& types);
+
+ template <class T>
+ [[nodiscard]] bool readPackedType(const TypeContext& types,
+ const FeatureArgs& features, T* type);
+
+ [[nodiscard]] bool readValType(const TypeContext& types,
+ const FeatureArgs& features, ValType* type);
+
+ [[nodiscard]] bool readFieldType(const TypeContext& types,
+ const FeatureArgs& features,
+ FieldType* type);
+
+ [[nodiscard]] bool readHeapType(const TypeContext& types,
+ const FeatureArgs& features, bool nullable,
+ RefType* type);
+
+ [[nodiscard]] bool readRefType(const TypeContext& types,
+ const FeatureArgs& features, RefType* type);
+
+ // Instruction opcode
+
+ [[nodiscard]] bool readOp(OpBytes* op);
+
+ // Instruction immediates for constant instructions
+
+ [[nodiscard]] bool readBinary() { return true; }
+ [[nodiscard]] bool readTypeIndex(uint32_t* typeIndex);
+ [[nodiscard]] bool readGlobalIndex(uint32_t* globalIndex);
+ [[nodiscard]] bool readFuncIndex(uint32_t* funcIndex);
+ [[nodiscard]] bool readI32Const(int32_t* i32);
+ [[nodiscard]] bool readI64Const(int64_t* i64);
+ [[nodiscard]] bool readF32Const(float* f32);
+ [[nodiscard]] bool readF64Const(double* f64);
+#ifdef ENABLE_WASM_SIMD
+ [[nodiscard]] bool readV128Const(V128* value);
+#endif
+ [[nodiscard]] bool readRefNull(const TypeContext& types,
+ const FeatureArgs& features, RefType* type);
+
+ // See writeBytes comment.
+
+ [[nodiscard]] bool readBytes(uint32_t numBytes,
+ const uint8_t** bytes = nullptr) {
+ if (bytes) {
+ *bytes = cur_;
+ }
+ if (bytesRemain() < numBytes) {
+ return false;
+ }
+ cur_ += numBytes;
+ return true;
+ }
+
+ // See "section" description in Encoder.
+
+ [[nodiscard]] bool readSectionHeader(uint8_t* id, SectionRange* range);
+
+ [[nodiscard]] bool startSection(SectionId id, ModuleEnvironment* env,
+ MaybeSectionRange* range,
+ const char* sectionName);
+ [[nodiscard]] bool finishSection(const SectionRange& range,
+ const char* sectionName);
+
+ // Custom sections do not cause validation errors unless the error is in
+ // the section header itself.
+
+ [[nodiscard]] bool startCustomSection(const char* expected,
+ size_t expectedLength,
+ ModuleEnvironment* env,
+ MaybeSectionRange* range);
+
+ template <size_t NameSizeWith0>
+ [[nodiscard]] bool startCustomSection(const char (&name)[NameSizeWith0],
+ ModuleEnvironment* env,
+ MaybeSectionRange* range) {
+ MOZ_ASSERT(name[NameSizeWith0 - 1] == '\0');
+ return startCustomSection(name, NameSizeWith0 - 1, env, range);
+ }
+
+ void finishCustomSection(const char* name, const SectionRange& range);
+ void skipAndFinishCustomSection(const SectionRange& range);
+
+ [[nodiscard]] bool skipCustomSection(ModuleEnvironment* env);
+
+ // The Name section has its own optional subsections.
+
+ [[nodiscard]] bool startNameSubsection(NameType nameType,
+ Maybe<uint32_t>* endOffset);
+ [[nodiscard]] bool finishNameSubsection(uint32_t endOffset);
+ [[nodiscard]] bool skipNameSubsection();
+
+ // The infallible "unchecked" decoding functions can be used when we are
+ // sure that the bytes are well-formed (by construction or due to previous
+ // validation).
+
+ uint8_t uncheckedReadFixedU8() { return uncheckedRead<uint8_t>(); }
+ uint32_t uncheckedReadFixedU32() { return uncheckedRead<uint32_t>(); }
+ void uncheckedReadFixedF32(float* out) { uncheckedRead<float>(out); }
+ void uncheckedReadFixedF64(double* out) { uncheckedRead<double>(out); }
+ template <typename UInt>
+ UInt uncheckedReadVarU() {
+ static const unsigned numBits = sizeof(UInt) * CHAR_BIT;
+ static const unsigned remainderBits = numBits % 7;
+ static const unsigned numBitsInSevens = numBits - remainderBits;
+ UInt decoded = 0;
+ uint32_t shift = 0;
+ do {
+ uint8_t byte = *cur_++;
+ if (!(byte & 0x80)) {
+ return decoded | (UInt(byte) << shift);
+ }
+ decoded |= UInt(byte & 0x7f) << shift;
+ shift += 7;
+ } while (shift != numBitsInSevens);
+ uint8_t byte = *cur_++;
+ MOZ_ASSERT(!(byte & 0xf0));
+ return decoded | (UInt(byte) << numBitsInSevens);
+ }
+ uint32_t uncheckedReadVarU32() { return uncheckedReadVarU<uint32_t>(); }
+ int32_t uncheckedReadVarS32() {
+ int32_t i32 = 0;
+ MOZ_ALWAYS_TRUE(readVarS32(&i32));
+ return i32;
+ }
+ uint64_t uncheckedReadVarU64() { return uncheckedReadVarU<uint64_t>(); }
+ int64_t uncheckedReadVarS64() {
+ int64_t i64 = 0;
+ MOZ_ALWAYS_TRUE(readVarS64(&i64));
+ return i64;
+ }
+ Op uncheckedReadOp() {
+ static_assert(size_t(Op::Limit) == 256, "fits");
+ uint8_t u8 = uncheckedReadFixedU8();
+ return u8 != UINT8_MAX ? Op(u8) : Op(uncheckedReadFixedU8() + UINT8_MAX);
+ }
+};
+
+// Value and reference types
+
+inline ValType Decoder::uncheckedReadValType(const TypeContext& types) {
+ uint8_t code = uncheckedReadFixedU8();
+ switch (code) {
+ case uint8_t(TypeCode::FuncRef):
+ case uint8_t(TypeCode::ExternRef):
+ return RefType::fromTypeCode(TypeCode(code), true);
+ case uint8_t(TypeCode::Ref):
+ case uint8_t(TypeCode::NullableRef): {
+ bool nullable = code == uint8_t(TypeCode::NullableRef);
+
+ uint8_t nextByte;
+ peekByte(&nextByte);
+
+ if ((nextByte & SLEB128SignMask) == SLEB128SignBit) {
+ uint8_t code = uncheckedReadFixedU8();
+ return RefType::fromTypeCode(TypeCode(code), nullable);
+ }
+
+ int32_t x = uncheckedReadVarS32();
+ const TypeDef* typeDef = &types.type(x);
+ return RefType::fromTypeDef(typeDef, nullable);
+ }
+ default:
+ return ValType::fromNonRefTypeCode(TypeCode(code));
+ }
+}
+
+template <class T>
+inline bool Decoder::readPackedType(const TypeContext& types,
+ const FeatureArgs& features, T* type) {
+ static_assert(uint8_t(TypeCode::Limit) <= UINT8_MAX, "fits");
+ uint8_t code;
+ if (!readFixedU8(&code)) {
+ return fail("expected type code");
+ }
+ switch (code) {
+ case uint8_t(TypeCode::V128): {
+#ifdef ENABLE_WASM_SIMD
+ if (!features.simd) {
+ return fail("v128 not enabled");
+ }
+ *type = T::fromNonRefTypeCode(TypeCode(code));
+ return true;
+#else
+ break;
+#endif
+ }
+ case uint8_t(TypeCode::FuncRef):
+ case uint8_t(TypeCode::ExternRef): {
+ *type = RefType::fromTypeCode(TypeCode(code), true);
+ return true;
+ }
+ case uint8_t(TypeCode::Ref):
+ case uint8_t(TypeCode::NullableRef): {
+#ifdef ENABLE_WASM_FUNCTION_REFERENCES
+ if (!features.functionReferences) {
+ return fail("(ref T) types not enabled");
+ }
+ bool nullable = code == uint8_t(TypeCode::NullableRef);
+ RefType refType;
+ if (!readHeapType(types, features, nullable, &refType)) {
+ return false;
+ }
+ *type = refType;
+ return true;
+#else
+ break;
+#endif
+ }
+ case uint8_t(TypeCode::AnyRef):
+ case uint8_t(TypeCode::EqRef):
+ case uint8_t(TypeCode::StructRef):
+ case uint8_t(TypeCode::ArrayRef):
+ case uint8_t(TypeCode::NullFuncRef):
+ case uint8_t(TypeCode::NullExternRef):
+ case uint8_t(TypeCode::NullAnyRef): {
+#ifdef ENABLE_WASM_GC
+ if (!features.gc) {
+ return fail("gc types not enabled");
+ }
+ *type = RefType::fromTypeCode(TypeCode(code), true);
+ return true;
+#else
+ break;
+#endif
+ }
+ default: {
+ if (!T::isValidTypeCode(TypeCode(code))) {
+ break;
+ }
+ *type = T::fromNonRefTypeCode(TypeCode(code));
+ return true;
+ }
+ }
+ return fail("bad type");
+}
+
+inline bool Decoder::readValType(const TypeContext& types,
+ const FeatureArgs& features, ValType* type) {
+ return readPackedType<ValType>(types, features, type);
+}
+
+inline bool Decoder::readFieldType(const TypeContext& types,
+ const FeatureArgs& features,
+ FieldType* type) {
+ return readPackedType<FieldType>(types, features, type);
+}
+
+inline bool Decoder::readHeapType(const TypeContext& types,
+ const FeatureArgs& features, bool nullable,
+ RefType* type) {
+ uint8_t nextByte;
+ if (!peekByte(&nextByte)) {
+ return fail("expected heap type code");
+ }
+
+ if ((nextByte & SLEB128SignMask) == SLEB128SignBit) {
+ uint8_t code;
+ if (!readFixedU8(&code)) {
+ return false;
+ }
+
+ switch (code) {
+ case uint8_t(TypeCode::FuncRef):
+ case uint8_t(TypeCode::ExternRef):
+ *type = RefType::fromTypeCode(TypeCode(code), nullable);
+ return true;
+#ifdef ENABLE_WASM_GC
+ case uint8_t(TypeCode::AnyRef):
+ case uint8_t(TypeCode::EqRef):
+ case uint8_t(TypeCode::StructRef):
+ case uint8_t(TypeCode::ArrayRef):
+ case uint8_t(TypeCode::NullFuncRef):
+ case uint8_t(TypeCode::NullExternRef):
+ case uint8_t(TypeCode::NullAnyRef):
+ if (!features.gc) {
+ return fail("gc types not enabled");
+ }
+ *type = RefType::fromTypeCode(TypeCode(code), nullable);
+ return true;
+#endif
+ default:
+ return fail("invalid heap type");
+ }
+ }
+
+#ifdef ENABLE_WASM_FUNCTION_REFERENCES
+ if (features.functionReferences) {
+ int32_t x;
+ if (!readVarS32(&x) || x < 0 || uint32_t(x) >= types.length()) {
+ return fail("invalid heap type index");
+ }
+ const TypeDef* typeDef = &types.type(x);
+ *type = RefType::fromTypeDef(typeDef, nullable);
+ return true;
+ }
+#endif
+ return fail("invalid heap type");
+}
+
+inline bool Decoder::readRefType(const TypeContext& types,
+ const FeatureArgs& features, RefType* type) {
+ ValType valType;
+ if (!readValType(types, features, &valType)) {
+ return false;
+ }
+ if (!valType.isRefType()) {
+ return fail("bad type");
+ }
+ *type = valType.refType();
+ return true;
+}
+
+// Instruction opcode
+
+inline bool Decoder::readOp(OpBytes* op) {
+ static_assert(size_t(Op::Limit) == 256, "fits");
+ uint8_t u8;
+ if (!readFixedU8(&u8)) {
+ return false;
+ }
+ op->b0 = u8;
+ if (MOZ_LIKELY(!IsPrefixByte(u8))) {
+ return true;
+ }
+ return readVarU32(&op->b1);
+}
+
+// Instruction immediates for constant instructions
+
+inline bool Decoder::readTypeIndex(uint32_t* typeIndex) {
+ if (!readVarU32(typeIndex)) {
+ return fail("unable to read type index");
+ }
+ return true;
+}
+
+inline bool Decoder::readGlobalIndex(uint32_t* globalIndex) {
+ if (!readVarU32(globalIndex)) {
+ return fail("unable to read global index");
+ }
+ return true;
+}
+
+inline bool Decoder::readFuncIndex(uint32_t* funcIndex) {
+ if (!readVarU32(funcIndex)) {
+ return fail("unable to read function index");
+ }
+ return true;
+}
+
+inline bool Decoder::readI32Const(int32_t* i32) {
+ if (!readVarS32(i32)) {
+ return fail("failed to read I32 constant");
+ }
+ return true;
+}
+
+inline bool Decoder::readI64Const(int64_t* i64) {
+ if (!readVarS64(i64)) {
+ return fail("failed to read I64 constant");
+ }
+ return true;
+}
+
+inline bool Decoder::readF32Const(float* f32) {
+ if (!readFixedF32(f32)) {
+ return fail("failed to read F32 constant");
+ }
+ return true;
+}
+
+inline bool Decoder::readF64Const(double* f64) {
+ if (!readFixedF64(f64)) {
+ return fail("failed to read F64 constant");
+ }
+ return true;
+}
+
+#ifdef ENABLE_WASM_SIMD
+inline bool Decoder::readV128Const(V128* value) {
+ if (!readFixedV128(value)) {
+ return fail("unable to read V128 constant");
+ }
+ return true;
+}
+#endif
+
+inline bool Decoder::readRefNull(const TypeContext& types,
+ const FeatureArgs& features, RefType* type) {
+ return readHeapType(types, features, true, type);
+}
+
+} // namespace wasm
+} // namespace js
+
+#endif // namespace wasm_binary_h
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-26 09:55:17 +0000