| // Copyright 2015 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/signature.h" |
| |
| #include "src/handles.h" |
| #include "src/v8.h" |
| #include "src/zone-containers.h" |
| |
| #include "src/wasm/ast-decoder.h" |
| #include "src/wasm/encoder.h" |
| #include "src/wasm/leb-helper.h" |
| #include "src/wasm/wasm-macro-gen.h" |
| #include "src/wasm/wasm-module.h" |
| #include "src/wasm/wasm-opcodes.h" |
| |
| #include "src/v8memory.h" |
| |
| #if DEBUG |
| #define TRACE(...) \ |
| do { \ |
| if (FLAG_trace_wasm_encoder) PrintF(__VA_ARGS__); \ |
| } while (false) |
| #else |
| #define TRACE(...) |
| #endif |
| |
| namespace v8 { |
| namespace internal { |
| namespace wasm { |
| |
| /*TODO: add error cases for adding too many locals, too many functions and bad |
| indices in body */ |
| |
| namespace { |
| void EmitUint8(byte** b, uint8_t x) { |
| Memory::uint8_at(*b) = x; |
| *b += 1; |
| } |
| |
| void EmitUint16(byte** b, uint16_t x) { |
| WriteUnalignedUInt16(*b, x); |
| *b += 2; |
| } |
| |
| void EmitUint32(byte** b, uint32_t x) { |
| WriteUnalignedUInt32(*b, x); |
| *b += 4; |
| } |
| |
| void EmitVarInt(byte** b, size_t val) { |
| LEBHelper::write_u32v(b, static_cast<uint32_t>(val)); |
| } |
| |
| // Sections all start with a size, but it's unknown at the start. |
| // We generate a large varint which we then fixup later when the size is known. |
| // |
| // TODO(jfb) Not strictly necessary since sizes are calculated ahead of time. |
| const size_t kPaddedVarintSize = 5; |
| |
| void FixupSection(byte* start, byte* end) { |
| // Same as LEBHelper::write_u32v, but fixed-width with zeroes in the MSBs. |
| size_t val = end - start - kPaddedVarintSize; |
| TRACE(" fixup %u\n", (unsigned)val); |
| for (size_t pos = 0; pos != kPaddedVarintSize; ++pos) { |
| size_t next = val >> 7; |
| byte out = static_cast<byte>(val & 0x7f); |
| if (pos != kPaddedVarintSize - 1) { |
| *(start++) = 0x80 | out; |
| val = next; |
| } else { |
| *(start++) = out; |
| // TODO(jfb) check that the pre-allocated fixup size isn't overflowed. |
| } |
| } |
| } |
| |
| // Returns the start of the section, where the section VarInt size is. |
| byte* EmitSection(WasmSection::Code code, byte** b) { |
| // Emit the section name. |
| const char* name = WasmSection::getName(code); |
| TRACE("emit section: %s\n", name); |
| size_t length = WasmSection::getNameLength(code); |
| EmitVarInt(b, length); // Section name string size. |
| for (size_t i = 0; i != length; ++i) EmitUint8(b, name[i]); |
| |
| // Emit a placeholder for the length. |
| byte* start = *b; |
| for (size_t padding = 0; padding != kPaddedVarintSize; ++padding) { |
| EmitUint8(b, 0xff); // Will get fixed up later. |
| } |
| |
| return start; |
| } |
| } // namespace |
| |
| WasmFunctionBuilder::WasmFunctionBuilder(Zone* zone) |
| : locals_(zone), exported_(0), body_(zone), name_(zone) {} |
| |
| void WasmFunctionBuilder::EmitVarInt(uint32_t val) { |
| byte buffer[8]; |
| byte* ptr = buffer; |
| LEBHelper::write_u32v(&ptr, val); |
| for (byte* p = buffer; p < ptr; p++) { |
| body_.push_back(*p); |
| } |
| } |
| |
| void WasmFunctionBuilder::SetSignature(FunctionSig* sig) { |
| DCHECK(!locals_.has_sig()); |
| locals_.set_sig(sig); |
| } |
| |
| uint32_t WasmFunctionBuilder::AddLocal(LocalType type) { |
| DCHECK(locals_.has_sig()); |
| return locals_.AddLocals(1, type); |
| } |
| |
| void WasmFunctionBuilder::EmitGetLocal(uint32_t local_index) { |
| EmitWithVarInt(kExprGetLocal, local_index); |
| } |
| |
| void WasmFunctionBuilder::EmitSetLocal(uint32_t local_index) { |
| EmitWithVarInt(kExprSetLocal, local_index); |
| } |
| |
| void WasmFunctionBuilder::EmitCode(const byte* code, uint32_t code_size) { |
| for (size_t i = 0; i < code_size; i++) { |
| body_.push_back(code[i]); |
| } |
| } |
| |
| void WasmFunctionBuilder::Emit(WasmOpcode opcode) { |
| body_.push_back(static_cast<byte>(opcode)); |
| } |
| |
| void WasmFunctionBuilder::EmitWithU8(WasmOpcode opcode, const byte immediate) { |
| body_.push_back(static_cast<byte>(opcode)); |
| body_.push_back(immediate); |
| } |
| |
| void WasmFunctionBuilder::EmitWithU8U8(WasmOpcode opcode, const byte imm1, |
| const byte imm2) { |
| body_.push_back(static_cast<byte>(opcode)); |
| body_.push_back(imm1); |
| body_.push_back(imm2); |
| } |
| |
| void WasmFunctionBuilder::EmitWithVarInt(WasmOpcode opcode, |
| uint32_t immediate) { |
| body_.push_back(static_cast<byte>(opcode)); |
| EmitVarInt(immediate); |
| } |
| |
| void WasmFunctionBuilder::EmitI32Const(int32_t value) { |
| // TODO(titzer): variable-length signed and unsigned i32 constants. |
| if (-128 <= value && value <= 127) { |
| EmitWithU8(kExprI8Const, static_cast<byte>(value)); |
| } else { |
| byte code[] = {WASM_I32V_5(value)}; |
| EmitCode(code, sizeof(code)); |
| } |
| } |
| |
| void WasmFunctionBuilder::Exported(uint8_t flag) { exported_ = flag; } |
| |
| void WasmFunctionBuilder::SetName(const char* name, int name_length) { |
| name_.clear(); |
| if (name_length > 0) { |
| for (int i = 0; i < name_length; i++) { |
| name_.push_back(*(name + i)); |
| } |
| } |
| } |
| |
| WasmFunctionEncoder* WasmFunctionBuilder::Build(Zone* zone, |
| WasmModuleBuilder* mb) const { |
| WasmFunctionEncoder* e = |
| new (zone) WasmFunctionEncoder(zone, locals_, exported_); |
| // TODO(titzer): lame memcpy here. |
| e->body_.insert(e->body_.begin(), body_.begin(), body_.end()); |
| e->signature_index_ = mb->AddSignature(locals_.get_sig()); |
| e->name_.insert(e->name_.begin(), name_.begin(), name_.end()); |
| return e; |
| } |
| |
| WasmFunctionEncoder::WasmFunctionEncoder(Zone* zone, LocalDeclEncoder locals, |
| bool exported) |
| : locals_(locals), exported_(exported), body_(zone), name_(zone) {} |
| |
| uint32_t WasmFunctionEncoder::HeaderSize() const { |
| uint32_t size = 3; |
| size += 2; |
| if (HasName()) { |
| uint32_t name_size = NameSize(); |
| size += |
| static_cast<uint32_t>(LEBHelper::sizeof_u32v(name_size)) + name_size; |
| } |
| return size; |
| } |
| |
| uint32_t WasmFunctionEncoder::BodySize(void) const { |
| return static_cast<uint32_t>(body_.size() + locals_.Size()); |
| } |
| |
| uint32_t WasmFunctionEncoder::NameSize() const { |
| return HasName() ? static_cast<uint32_t>(name_.size()) : 0; |
| } |
| |
| void WasmFunctionEncoder::Serialize(byte* buffer, byte** header, |
| byte** body) const { |
| uint8_t decl_bits = (exported_ ? kDeclFunctionExport : 0) | |
| (HasName() ? kDeclFunctionName : 0); |
| |
| EmitUint8(header, decl_bits); |
| EmitUint16(header, signature_index_); |
| |
| if (HasName()) { |
| EmitVarInt(header, NameSize()); |
| for (size_t i = 0; i < name_.size(); ++i) { |
| EmitUint8(header, name_[i]); |
| } |
| } |
| |
| EmitUint16(header, static_cast<uint16_t>(body_.size() + locals_.Size())); |
| (*header) += locals_.Emit(*header); |
| if (body_.size() > 0) { |
| std::memcpy(*header, &body_[0], body_.size()); |
| (*header) += body_.size(); |
| } |
| } |
| |
| WasmDataSegmentEncoder::WasmDataSegmentEncoder(Zone* zone, const byte* data, |
| uint32_t size, uint32_t dest) |
| : data_(zone), dest_(dest) { |
| for (size_t i = 0; i < size; i++) { |
| data_.push_back(data[i]); |
| } |
| } |
| |
| uint32_t WasmDataSegmentEncoder::HeaderSize() const { |
| static const int kDataSegmentSize = 13; |
| return kDataSegmentSize; |
| } |
| |
| uint32_t WasmDataSegmentEncoder::BodySize() const { |
| return static_cast<uint32_t>(data_.size()); |
| } |
| |
| void WasmDataSegmentEncoder::Serialize(byte* buffer, byte** header, |
| byte** body) const { |
| EmitVarInt(header, dest_); |
| EmitVarInt(header, static_cast<uint32_t>(data_.size())); |
| |
| std::memcpy(*header, &data_[0], data_.size()); |
| (*header) += data_.size(); |
| } |
| |
| WasmModuleBuilder::WasmModuleBuilder(Zone* zone) |
| : zone_(zone), |
| signatures_(zone), |
| imports_(zone), |
| functions_(zone), |
| data_segments_(zone), |
| indirect_functions_(zone), |
| globals_(zone), |
| signature_map_(zone), |
| start_function_index_(-1) {} |
| |
| uint32_t WasmModuleBuilder::AddFunction() { |
| functions_.push_back(new (zone_) WasmFunctionBuilder(zone_)); |
| return static_cast<uint32_t>(functions_.size() - 1); |
| } |
| |
| WasmFunctionBuilder* WasmModuleBuilder::FunctionAt(size_t index) { |
| if (functions_.size() > index) { |
| return functions_.at(index); |
| } else { |
| return nullptr; |
| } |
| } |
| |
| void WasmModuleBuilder::AddDataSegment(WasmDataSegmentEncoder* data) { |
| data_segments_.push_back(data); |
| } |
| |
| bool WasmModuleBuilder::CompareFunctionSigs::operator()(FunctionSig* a, |
| FunctionSig* b) const { |
| if (a->return_count() < b->return_count()) return true; |
| if (a->return_count() > b->return_count()) return false; |
| if (a->parameter_count() < b->parameter_count()) return true; |
| if (a->parameter_count() > b->parameter_count()) return false; |
| for (size_t r = 0; r < a->return_count(); r++) { |
| if (a->GetReturn(r) < b->GetReturn(r)) return true; |
| if (a->GetReturn(r) > b->GetReturn(r)) return false; |
| } |
| for (size_t p = 0; p < a->parameter_count(); p++) { |
| if (a->GetParam(p) < b->GetParam(p)) return true; |
| if (a->GetParam(p) > b->GetParam(p)) return false; |
| } |
| return false; |
| } |
| |
| uint32_t WasmModuleBuilder::AddSignature(FunctionSig* sig) { |
| SignatureMap::iterator pos = signature_map_.find(sig); |
| if (pos != signature_map_.end()) { |
| return pos->second; |
| } else { |
| uint32_t index = static_cast<uint32_t>(signatures_.size()); |
| signature_map_[sig] = index; |
| signatures_.push_back(sig); |
| return index; |
| } |
| } |
| |
| void WasmModuleBuilder::AddIndirectFunction(uint32_t index) { |
| indirect_functions_.push_back(index); |
| } |
| |
| uint32_t WasmModuleBuilder::AddImport(const char* name, int name_length, |
| FunctionSig* sig) { |
| imports_.push_back({AddSignature(sig), name, name_length}); |
| return static_cast<uint32_t>(imports_.size() - 1); |
| } |
| |
| void WasmModuleBuilder::MarkStartFunction(uint32_t index) { |
| start_function_index_ = index; |
| } |
| |
| WasmModuleWriter* WasmModuleBuilder::Build(Zone* zone) { |
| WasmModuleWriter* writer = new (zone) WasmModuleWriter(zone); |
| for (auto import : imports_) { |
| writer->imports_.push_back(import); |
| } |
| for (auto function : functions_) { |
| writer->functions_.push_back(function->Build(zone, this)); |
| } |
| for (auto segment : data_segments_) { |
| writer->data_segments_.push_back(segment); |
| } |
| for (auto sig : signatures_) { |
| writer->signatures_.push_back(sig); |
| } |
| for (auto index : indirect_functions_) { |
| writer->indirect_functions_.push_back(index); |
| } |
| for (auto global : globals_) { |
| writer->globals_.push_back(global); |
| } |
| writer->start_function_index_ = start_function_index_; |
| return writer; |
| } |
| |
| uint32_t WasmModuleBuilder::AddGlobal(MachineType type, bool exported) { |
| globals_.push_back(std::make_pair(type, exported)); |
| return static_cast<uint32_t>(globals_.size() - 1); |
| } |
| |
| WasmModuleWriter::WasmModuleWriter(Zone* zone) |
| : imports_(zone), |
| functions_(zone), |
| data_segments_(zone), |
| signatures_(zone), |
| indirect_functions_(zone), |
| globals_(zone) {} |
| |
| struct Sizes { |
| size_t header_size; |
| size_t body_size; |
| |
| size_t total() { return header_size + body_size; } |
| |
| void Add(size_t header, size_t body) { |
| header_size += header; |
| body_size += body; |
| } |
| |
| void AddSection(WasmSection::Code code, size_t other_size) { |
| Add(kPaddedVarintSize + |
| LEBHelper::sizeof_u32v(WasmSection::getNameLength(code)) + |
| WasmSection::getNameLength(code), |
| 0); |
| if (other_size) Add(LEBHelper::sizeof_u32v(other_size), 0); |
| } |
| }; |
| |
| WasmModuleIndex* WasmModuleWriter::WriteTo(Zone* zone) const { |
| Sizes sizes = {0, 0}; |
| |
| sizes.Add(2 * sizeof(uint32_t), 0); // header |
| |
| if (globals_.size() > 0) { |
| sizes.AddSection(WasmSection::Code::Globals, globals_.size()); |
| /* These globals never have names, so are always 3 bytes. */ |
| sizes.Add(3 * globals_.size(), 0); |
| TRACE("Size after globals: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| if (signatures_.size() > 0) { |
| sizes.AddSection(WasmSection::Code::Signatures, signatures_.size()); |
| for (auto sig : signatures_) { |
| sizes.Add(1 + LEBHelper::sizeof_u32v(sig->parameter_count()) + |
| sig->parameter_count() + |
| LEBHelper::sizeof_u32v(sig->return_count()) + |
| sig->return_count(), |
| 0); |
| } |
| TRACE("Size after signatures: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| if (functions_.size() > 0) { |
| sizes.AddSection(WasmSection::Code::OldFunctions, functions_.size()); |
| for (auto function : functions_) { |
| sizes.Add(function->HeaderSize() + function->BodySize(), |
| function->NameSize()); |
| } |
| TRACE("Size after functions: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| if (imports_.size() > 0) { |
| sizes.AddSection(WasmSection::Code::ImportTable, imports_.size()); |
| for (auto import : imports_) { |
| sizes.Add(LEBHelper::sizeof_u32v(import.sig_index), 0); |
| sizes.Add(LEBHelper::sizeof_u32v(import.name_length), 0); |
| sizes.Add(import.name_length, 0); |
| sizes.Add(1, 0); |
| } |
| TRACE("Size after imports: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| if (indirect_functions_.size() > 0) { |
| sizes.AddSection(WasmSection::Code::FunctionTable, |
| indirect_functions_.size()); |
| for (auto function_index : indirect_functions_) { |
| sizes.Add(LEBHelper::sizeof_u32v(function_index), 0); |
| } |
| TRACE("Size after indirect functions: %u, %u\n", |
| (unsigned)sizes.header_size, (unsigned)sizes.body_size); |
| } |
| |
| sizes.AddSection(WasmSection::Code::Memory, 0); |
| sizes.Add(kDeclMemorySize, 0); |
| TRACE("Size after memory: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| |
| if (start_function_index_ >= 0) { |
| sizes.AddSection(WasmSection::Code::StartFunction, 0); |
| sizes.Add(LEBHelper::sizeof_u32v(start_function_index_), 0); |
| TRACE("Size after start: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| if (data_segments_.size() > 0) { |
| sizes.AddSection(WasmSection::Code::DataSegments, data_segments_.size()); |
| for (auto segment : data_segments_) { |
| sizes.Add(segment->HeaderSize(), segment->BodySize()); |
| } |
| TRACE("Size after data segments: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| if (sizes.body_size > 0) { |
| sizes.AddSection(WasmSection::Code::End, 0); |
| TRACE("Size after end: %u, %u\n", (unsigned)sizes.header_size, |
| (unsigned)sizes.body_size); |
| } |
| |
| ZoneVector<uint8_t> buffer_vector(sizes.total(), zone); |
| byte* buffer = &buffer_vector[0]; |
| byte* header = buffer; |
| byte* body = buffer + sizes.header_size; |
| |
| // -- emit magic ------------------------------------------------------------- |
| TRACE("emit magic\n"); |
| EmitUint32(&header, kWasmMagic); |
| EmitUint32(&header, kWasmVersion); |
| |
| // -- emit globals ----------------------------------------------------------- |
| if (globals_.size() > 0) { |
| byte* section = EmitSection(WasmSection::Code::Globals, &header); |
| EmitVarInt(&header, globals_.size()); |
| |
| for (auto global : globals_) { |
| EmitVarInt(&header, 0); // Length of the global name. |
| EmitUint8(&header, WasmOpcodes::MemTypeCodeFor(global.first)); |
| EmitUint8(&header, global.second); |
| } |
| FixupSection(section, header); |
| } |
| |
| // -- emit signatures -------------------------------------------------------- |
| if (signatures_.size() > 0) { |
| byte* section = EmitSection(WasmSection::Code::Signatures, &header); |
| EmitVarInt(&header, signatures_.size()); |
| |
| for (FunctionSig* sig : signatures_) { |
| EmitUint8(&header, kWasmFunctionTypeForm); |
| EmitVarInt(&header, sig->parameter_count()); |
| for (size_t j = 0; j < sig->parameter_count(); j++) { |
| EmitUint8(&header, WasmOpcodes::LocalTypeCodeFor(sig->GetParam(j))); |
| } |
| EmitVarInt(&header, sig->return_count()); |
| for (size_t j = 0; j < sig->return_count(); j++) { |
| EmitUint8(&header, WasmOpcodes::LocalTypeCodeFor(sig->GetReturn(j))); |
| } |
| } |
| FixupSection(section, header); |
| } |
| |
| // -- emit imports ----------------------------------------------------------- |
| if (imports_.size() > 0) { |
| byte* section = EmitSection(WasmSection::Code::ImportTable, &header); |
| EmitVarInt(&header, imports_.size()); |
| for (auto import : imports_) { |
| EmitVarInt(&header, import.sig_index); |
| EmitVarInt(&header, import.name_length); |
| std::memcpy(header, import.name, import.name_length); |
| header += import.name_length; |
| EmitVarInt(&header, 0); |
| } |
| FixupSection(section, header); |
| } |
| |
| // -- emit functions --------------------------------------------------------- |
| if (functions_.size() > 0) { |
| byte* section = EmitSection(WasmSection::Code::OldFunctions, &header); |
| EmitVarInt(&header, functions_.size()); |
| |
| for (auto func : functions_) { |
| func->Serialize(buffer, &header, &body); |
| } |
| FixupSection(section, header); |
| } |
| |
| // -- emit function table ---------------------------------------------------- |
| if (indirect_functions_.size() > 0) { |
| byte* section = EmitSection(WasmSection::Code::FunctionTable, &header); |
| EmitVarInt(&header, indirect_functions_.size()); |
| |
| for (auto index : indirect_functions_) { |
| EmitVarInt(&header, index); |
| } |
| FixupSection(section, header); |
| } |
| |
| // -- emit memory declaration ------------------------------------------------ |
| { |
| byte* section = EmitSection(WasmSection::Code::Memory, &header); |
| EmitVarInt(&header, 16); // min memory size |
| EmitVarInt(&header, 16); // max memory size |
| EmitUint8(&header, 0); // memory export |
| static_assert(kDeclMemorySize == 3, "memory size must match emit above"); |
| FixupSection(section, header); |
| } |
| |
| // -- emit start function index ---------------------------------------------- |
| if (start_function_index_ >= 0) { |
| byte* section = EmitSection(WasmSection::Code::StartFunction, &header); |
| EmitVarInt(&header, start_function_index_); |
| FixupSection(section, header); |
| } |
| |
| // -- emit data segments ----------------------------------------------------- |
| if (data_segments_.size() > 0) { |
| byte* section = EmitSection(WasmSection::Code::DataSegments, &header); |
| EmitVarInt(&header, data_segments_.size()); |
| |
| for (auto segment : data_segments_) { |
| segment->Serialize(buffer, &header, &body); |
| } |
| FixupSection(section, header); |
| } |
| |
| if (sizes.body_size > 0) { |
| byte* section = EmitSection(WasmSection::Code::End, &header); |
| FixupSection(section, header); |
| } |
| |
| return new (zone) WasmModuleIndex(buffer, buffer + sizes.total()); |
| } |
| } // namespace wasm |
| } // namespace internal |
| } // namespace v8 |