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// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/wasm/streaming-decoder.h"
#include "src/base/template-utils.h"
#include "src/handles.h"
#include "src/objects-inl.h"
#include "src/objects/descriptor-array.h"
#include "src/objects/dictionary.h"
#include "src/wasm/decoder.h"
#include "src/wasm/leb-helper.h"
#include "src/wasm/module-decoder.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-objects.h"
#include "src/wasm/wasm-result.h"
#define TRACE_STREAMING(...) \
do { \
if (FLAG_trace_wasm_streaming) PrintF(__VA_ARGS__); \
} while (false)
namespace v8 {
namespace internal {
namespace wasm {
void StreamingDecoder::OnBytesReceived(Vector<const uint8_t> bytes) {
TRACE_STREAMING("OnBytesReceived(%zu bytes)\n", bytes.size());
size_t current = 0;
while (ok() && current < bytes.size()) {
size_t num_bytes =
state_->ReadBytes(this, bytes.SubVector(current, bytes.size()));
current += num_bytes;
module_offset_ += num_bytes;
if (state_->is_finished()) {
state_ = state_->Next(this);
}
}
total_size_ += bytes.size();
if (ok()) {
processor_->OnFinishedChunk();
}
}
size_t StreamingDecoder::DecodingState::ReadBytes(StreamingDecoder* streaming,
Vector<const uint8_t> bytes) {
size_t num_bytes = std::min(bytes.size(), remaining());
TRACE_STREAMING("ReadBytes(%zu bytes)\n", num_bytes);
memcpy(buffer() + offset(), &bytes.first(), num_bytes);
set_offset(offset() + num_bytes);
return num_bytes;
}
void StreamingDecoder::Finish() {
TRACE_STREAMING("Finish\n");
if (!ok()) {
return;
}
if (!state_->is_finishing_allowed()) {
// The byte stream ended too early, we report an error.
Error("unexpected end of stream");
return;
}
OwnedVector<uint8_t> bytes = OwnedVector<uint8_t>::New(total_size_);
uint8_t* cursor = bytes.start();
{
#define BYTES(x) (x & 0xFF), (x >> 8) & 0xFF, (x >> 16) & 0xFF, (x >> 24) & 0xFF
uint8_t module_header[]{BYTES(kWasmMagic), BYTES(kWasmVersion)};
#undef BYTES
memcpy(cursor, module_header, arraysize(module_header));
cursor += arraysize(module_header);
}
for (auto&& buffer : section_buffers_) {
DCHECK_LE(cursor - bytes.start() + buffer->length(), total_size_);
memcpy(cursor, buffer->bytes(), buffer->length());
cursor += buffer->length();
}
processor_->OnFinishedStream(std::move(bytes));
}
void StreamingDecoder::Abort() {
TRACE_STREAMING("Abort\n");
if (ok()) processor_->OnAbort();
}
// An abstract class to share code among the states which decode VarInts. This
// class takes over the decoding of the VarInt and then calls the actual decode
// code with the decoded value.
class StreamingDecoder::DecodeVarInt32 : public DecodingState {
public:
explicit DecodeVarInt32(size_t max_value, const char* field_name)
: max_value_(max_value), field_name_(field_name) {}
uint8_t* buffer() override { return byte_buffer_; }
size_t size() const override { return kMaxVarInt32Size; }
size_t ReadBytes(StreamingDecoder* streaming,
Vector<const uint8_t> bytes) override;
std::unique_ptr<DecodingState> Next(StreamingDecoder* streaming) override;
virtual std::unique_ptr<DecodingState> NextWithValue(
StreamingDecoder* streaming) = 0;
protected:
uint8_t byte_buffer_[kMaxVarInt32Size];
// The maximum valid value decoded in this state. {Next} returns an error if
// this value is exceeded.
size_t max_value_;
const char* field_name_;
size_t value_ = 0;
size_t bytes_consumed_ = 0;
};
class StreamingDecoder::DecodeModuleHeader : public DecodingState {
public:
size_t size() const override { return kModuleHeaderSize; }
uint8_t* buffer() override { return byte_buffer_; }
std::unique_ptr<DecodingState> Next(StreamingDecoder* streaming) override;
private:
// Checks if the magic bytes of the module header are correct.
void CheckHeader(Decoder* decoder);
// The size of the module header.
static constexpr size_t kModuleHeaderSize = 8;
uint8_t byte_buffer_[kModuleHeaderSize];
};
class StreamingDecoder::DecodeSectionID : public DecodingState {
public:
explicit DecodeSectionID(uint32_t module_offset)
: module_offset_(module_offset) {}
size_t size() const override { return 1; }
uint8_t* buffer() override { return &id_; }
bool is_finishing_allowed() const override { return true; }
std::unique_ptr<DecodingState> Next(StreamingDecoder* streaming) override;
private:
uint8_t id_ = 0;
// The start offset of this section in the module.
uint32_t module_offset_;
};
class StreamingDecoder::DecodeSectionLength : public DecodeVarInt32 {
public:
explicit DecodeSectionLength(uint8_t id, uint32_t module_offset)
: DecodeVarInt32(kV8MaxWasmModuleSize, "section length"),
section_id_(id),
module_offset_(module_offset) {}
std::unique_ptr<DecodingState> NextWithValue(
StreamingDecoder* streaming) override;
private:
uint8_t section_id_;
// The start offset of this section in the module.
uint32_t module_offset_;
};
class StreamingDecoder::DecodeSectionPayload : public DecodingState {
public:
explicit DecodeSectionPayload(SectionBuffer* section_buffer)
: section_buffer_(section_buffer) {}
size_t size() const override { return section_buffer_->payload_length(); }
uint8_t* buffer() override {
return section_buffer_->bytes() + section_buffer_->payload_offset();
}
std::unique_ptr<DecodingState> Next(StreamingDecoder* streaming) override;
private:
SectionBuffer* section_buffer_;
};
class StreamingDecoder::DecodeNumberOfFunctions : public DecodeVarInt32 {
public:
explicit DecodeNumberOfFunctions(SectionBuffer* section_buffer)
: DecodeVarInt32(kV8MaxWasmFunctions, "functions count"),
section_buffer_(section_buffer) {}
std::unique_ptr<DecodingState> NextWithValue(
StreamingDecoder* streaming) override;
private:
SectionBuffer* section_buffer_;
};
class StreamingDecoder::DecodeFunctionLength : public DecodeVarInt32 {
public:
explicit DecodeFunctionLength(SectionBuffer* section_buffer,
size_t buffer_offset,
size_t num_remaining_functions)
: DecodeVarInt32(kV8MaxWasmFunctionSize, "body size"),
section_buffer_(section_buffer),
buffer_offset_(buffer_offset),
// We are reading a new function, so one function less is remaining.
num_remaining_functions_(num_remaining_functions - 1) {
DCHECK_GT(num_remaining_functions, 0);
}
std::unique_ptr<DecodingState> NextWithValue(
StreamingDecoder* streaming) override;
private:
SectionBuffer* section_buffer_;
size_t buffer_offset_;
size_t num_remaining_functions_;
};
class StreamingDecoder::DecodeFunctionBody : public DecodingState {
public:
explicit DecodeFunctionBody(SectionBuffer* section_buffer,
size_t buffer_offset, size_t function_length,
size_t num_remaining_functions,
uint32_t module_offset)
: section_buffer_(section_buffer),
buffer_offset_(buffer_offset),
size_(function_length),
num_remaining_functions_(num_remaining_functions),
module_offset_(module_offset) {}
size_t size() const override { return size_; }
uint8_t* buffer() override {
return section_buffer_->bytes() + buffer_offset_;
}
std::unique_ptr<DecodingState> Next(StreamingDecoder* streaming) override;
private:
SectionBuffer* section_buffer_;
size_t buffer_offset_;
size_t size_;
size_t num_remaining_functions_;
uint32_t module_offset_;
};
size_t StreamingDecoder::DecodeVarInt32::ReadBytes(
StreamingDecoder* streaming, Vector<const uint8_t> bytes) {
size_t bytes_read = std::min(bytes.size(), remaining());
TRACE_STREAMING("ReadBytes of a VarInt\n");
memcpy(buffer() + offset(), &bytes.first(), bytes_read);
Decoder decoder(buffer(), buffer() + offset() + bytes_read,
streaming->module_offset());
value_ = decoder.consume_u32v(field_name_);
// The number of bytes we actually needed to read.
DCHECK_GT(decoder.pc(), buffer());
bytes_consumed_ = static_cast<size_t>(decoder.pc() - buffer());
TRACE_STREAMING(" ==> %zu bytes consumed\n", bytes_consumed_);
if (decoder.failed()) {
if (offset() + bytes_read == size()) {
// We only report an error if we read all bytes.
streaming->Error(decoder.toResult(nullptr));
}
set_offset(offset() + bytes_read);
return bytes_read;
} else {
DCHECK_GT(bytes_consumed_, offset());
size_t result = bytes_consumed_ - offset();
// We read all the bytes we needed.
set_offset(size());
return result;
}
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeVarInt32::Next(StreamingDecoder* streaming) {
if (!streaming->ok()) {
return nullptr;
}
if (value_ > max_value_) {
std::ostringstream oss;
oss << "function size > maximum function size: " << value_ << " < "
<< max_value_;
return streaming->Error(oss.str());
}
return NextWithValue(streaming);
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeModuleHeader::Next(StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeModuleHeader\n");
streaming->ProcessModuleHeader();
if (streaming->ok()) {
return base::make_unique<DecodeSectionID>(streaming->module_offset());
}
return nullptr;
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeSectionID::Next(StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeSectionID: %s section\n",
SectionName(static_cast<SectionCode>(id_)));
return base::make_unique<DecodeSectionLength>(id_, module_offset_);
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeSectionLength::NextWithValue(
StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeSectionLength(%zu)\n", value_);
SectionBuffer* buf = streaming->CreateNewBuffer(
module_offset_, section_id_, value_,
Vector<const uint8_t>(buffer(), static_cast<int>(bytes_consumed_)));
if (!buf) return nullptr;
if (value_ == 0) {
if (section_id_ == SectionCode::kCodeSectionCode) {
return streaming->Error("Code section cannot have size 0");
} else {
streaming->ProcessSection(buf);
if (streaming->ok()) {
// There is no payload, we go to the next section immediately.
return base::make_unique<DecodeSectionID>(streaming->module_offset_);
} else {
return nullptr;
}
}
} else {
if (section_id_ == SectionCode::kCodeSectionCode) {
// We reached the code section. All functions of the code section are put
// into the same SectionBuffer.
return base::make_unique<DecodeNumberOfFunctions>(buf);
} else {
return base::make_unique<DecodeSectionPayload>(buf);
}
}
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeSectionPayload::Next(StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeSectionPayload\n");
streaming->ProcessSection(section_buffer_);
if (streaming->ok()) {
return base::make_unique<DecodeSectionID>(streaming->module_offset());
}
return nullptr;
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeNumberOfFunctions::NextWithValue(
StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeNumberOfFunctions(%zu)\n", value_);
// Copy the bytes we read into the section buffer.
if (section_buffer_->payload_length() >= bytes_consumed_) {
memcpy(section_buffer_->bytes() + section_buffer_->payload_offset(),
buffer(), bytes_consumed_);
} else {
return streaming->Error("Invalid code section length");
}
// {value} is the number of functions.
if (value_ > 0) {
streaming->StartCodeSection(value_);
if (!streaming->ok()) return nullptr;
return base::make_unique<DecodeFunctionLength>(
section_buffer_, section_buffer_->payload_offset() + bytes_consumed_,
value_);
} else {
if (section_buffer_->payload_length() != bytes_consumed_) {
return streaming->Error("not all code section bytes were consumed");
}
return base::make_unique<DecodeSectionID>(streaming->module_offset());
}
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeFunctionLength::NextWithValue(
StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeFunctionLength(%zu)\n", value_);
// Copy the bytes we consumed into the section buffer.
if (section_buffer_->length() >= buffer_offset_ + bytes_consumed_) {
memcpy(section_buffer_->bytes() + buffer_offset_, buffer(),
bytes_consumed_);
} else {
return streaming->Error("Invalid code section length");
}
// {value} is the length of the function.
if (value_ == 0) {
return streaming->Error("Invalid function length (0)");
} else if (buffer_offset_ + bytes_consumed_ + value_ >
section_buffer_->length()) {
streaming->Error("not enough code section bytes");
return nullptr;
}
return base::make_unique<DecodeFunctionBody>(
section_buffer_, buffer_offset_ + bytes_consumed_, value_,
num_remaining_functions_, streaming->module_offset());
}
std::unique_ptr<StreamingDecoder::DecodingState>
StreamingDecoder::DecodeFunctionBody::Next(StreamingDecoder* streaming) {
TRACE_STREAMING("DecodeFunctionBody\n");
streaming->ProcessFunctionBody(
Vector<const uint8_t>(buffer(), static_cast<int>(size())),
module_offset_);
if (!streaming->ok()) {
return nullptr;
}
if (num_remaining_functions_ != 0) {
return base::make_unique<DecodeFunctionLength>(
section_buffer_, buffer_offset_ + size(), num_remaining_functions_);
} else {
if (buffer_offset_ + size() != section_buffer_->length()) {
return streaming->Error("not all code section bytes were used");
}
return base::make_unique<DecodeSectionID>(streaming->module_offset());
}
}
StreamingDecoder::StreamingDecoder(
std::unique_ptr<StreamingProcessor> processor)
: processor_(std::move(processor)),
// A module always starts with a module header.
state_(new DecodeModuleHeader()) {}
} // namespace wasm
} // namespace internal
} // namespace v8
#undef TRACE_STREAMING
|