/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: * * Copyright 2016 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. */ #include "wasm/WasmBinaryFormat.h" #include "mozilla/CheckedInt.h" #include "jsprf.h" #include "jit/JitOptions.h" using namespace js; using namespace js::wasm; using mozilla::CheckedInt; bool wasm::DecodePreamble(Decoder& d) { uint32_t u32; if (!d.readFixedU32(&u32) || u32 != MagicNumber) return d.fail("failed to match magic number"); if (!d.readFixedU32(&u32) || (u32 != EncodingVersion && u32 != PrevEncodingVersion)) { return d.fail("binary version 0x%" PRIx32 " does not match expected version 0x%" PRIx32, u32, EncodingVersion); } return true; } static bool DecodeValType(Decoder& d, ModuleKind kind, ValType* type) { uint8_t unchecked; if (!d.readValType(&unchecked)) return false; switch (unchecked) { case uint8_t(ValType::I32): case uint8_t(ValType::F32): case uint8_t(ValType::F64): case uint8_t(ValType::I64): *type = ValType(unchecked); return true; case uint8_t(ValType::I8x16): case uint8_t(ValType::I16x8): case uint8_t(ValType::I32x4): case uint8_t(ValType::F32x4): case uint8_t(ValType::B8x16): case uint8_t(ValType::B16x8): case uint8_t(ValType::B32x4): if (kind != ModuleKind::AsmJS) return d.fail("bad type"); *type = ValType(unchecked); return true; default: break; } return d.fail("bad type"); } bool wasm::DecodeTypeSection(Decoder& d, SigWithIdVector* sigs) { uint32_t sectionStart, sectionSize; if (!d.startSection(SectionId::Type, §ionStart, §ionSize, "type")) return false; if (sectionStart == Decoder::NotStarted) return true; uint32_t numSigs; if (!d.readVarU32(&numSigs)) return d.fail("expected number of signatures"); if (numSigs > MaxSigs) return d.fail("too many signatures"); if (!sigs->resize(numSigs)) return false; for (uint32_t sigIndex = 0; sigIndex < numSigs; sigIndex++) { uint32_t form; if (!d.readVarU32(&form) || form != uint32_t(TypeCode::Func)) return d.fail("expected function form"); uint32_t numArgs; if (!d.readVarU32(&numArgs)) return d.fail("bad number of function args"); if (numArgs > MaxArgsPerFunc) return d.fail("too many arguments in signature"); ValTypeVector args; if (!args.resize(numArgs)) return false; for (uint32_t i = 0; i < numArgs; i++) { if (!DecodeValType(d, ModuleKind::Wasm, &args[i])) return false; } uint32_t numRets; if (!d.readVarU32(&numRets)) return d.fail("bad number of function returns"); if (numRets > 1) return d.fail("too many returns in signature"); ExprType result = ExprType::Void; if (numRets == 1) { ValType type; if (!DecodeValType(d, ModuleKind::Wasm, &type)) return false; result = ToExprType(type); } (*sigs)[sigIndex] = Sig(Move(args), result); } if (!d.finishSection(sectionStart, sectionSize, "type")) return false; return true; } UniqueChars wasm::DecodeName(Decoder& d) { uint32_t numBytes; if (!d.readVarU32(&numBytes)) return nullptr; const uint8_t* bytes; if (!d.readBytes(numBytes, &bytes)) return nullptr; UniqueChars name(js_pod_malloc(numBytes + 1)); if (!name) return nullptr; memcpy(name.get(), bytes, numBytes); name[numBytes] = '\0'; return name; } static bool DecodeSignatureIndex(Decoder& d, const SigWithIdVector& sigs, uint32_t* sigIndex) { if (!d.readVarU32(sigIndex)) return d.fail("expected signature index"); if (*sigIndex >= sigs.length()) return d.fail("signature index out of range"); return true; } bool wasm::DecodeTableLimits(Decoder& d, TableDescVector* tables) { uint32_t elementType; if (!d.readVarU32(&elementType)) return d.fail("expected table element type"); if (elementType != uint32_t(TypeCode::AnyFunc)) return d.fail("expected 'anyfunc' element type"); Limits limits; if (!DecodeLimits(d, &limits)) return false; if (tables->length()) return d.fail("already have default table"); return tables->emplaceBack(TableKind::AnyFunction, limits); } bool wasm::GlobalIsJSCompatible(Decoder& d, ValType type, bool isMutable) { switch (type) { case ValType::I32: case ValType::F32: case ValType::F64: break; case ValType::I64: if (!jit::JitOptions.wasmTestMode) return d.fail("can't import/export an Int64 global to JS"); break; default: return d.fail("unexpected variable type in global import/export"); } if (isMutable) return d.fail("can't import/export mutable globals in the MVP"); return true; } static bool DecodeImport(Decoder& d, const SigWithIdVector& sigs, Uint32Vector* funcSigIndices, GlobalDescVector* globals, TableDescVector* tables, Maybe* memory, ImportVector* imports) { UniqueChars moduleName = DecodeName(d); if (!moduleName) return d.fail("expected valid import module name"); UniqueChars funcName = DecodeName(d); if (!funcName) return d.fail("expected valid import func name"); uint32_t rawImportKind; if (!d.readVarU32(&rawImportKind)) return d.fail("failed to read import kind"); DefinitionKind importKind = DefinitionKind(rawImportKind); switch (importKind) { case DefinitionKind::Function: { uint32_t sigIndex; if (!DecodeSignatureIndex(d, sigs, &sigIndex)) return false; if (!funcSigIndices->append(sigIndex)) return false; break; } case DefinitionKind::Table: { if (!DecodeTableLimits(d, tables)) return false; break; } case DefinitionKind::Memory: { Limits limits; if (!DecodeMemoryLimits(d, !!*memory, &limits)) return false; memory->emplace(limits); break; } case DefinitionKind::Global: { ValType type; bool isMutable; if (!DecodeGlobalType(d, &type, &isMutable)) return false; if (!GlobalIsJSCompatible(d, type, isMutable)) return false; if (!globals->append(GlobalDesc(type, isMutable, globals->length()))) return false; break; } default: return d.fail("unsupported import kind"); } return imports->emplaceBack(Move(moduleName), Move(funcName), importKind); } bool wasm::DecodeImportSection(Decoder& d, const SigWithIdVector& sigs, Uint32Vector* funcSigIndices, GlobalDescVector* globals, TableDescVector* tables, Maybe* memory, ImportVector* imports) { uint32_t sectionStart, sectionSize; if (!d.startSection(SectionId::Import, §ionStart, §ionSize, "import")) return false; if (sectionStart == Decoder::NotStarted) return true; uint32_t numImports; if (!d.readVarU32(&numImports)) return d.fail("failed to read number of imports"); if (numImports > MaxImports) return d.fail("too many imports"); for (uint32_t i = 0; i < numImports; i++) { if (!DecodeImport(d, sigs, funcSigIndices, globals, tables, memory, imports)) return false; } if (!d.finishSection(sectionStart, sectionSize, "import")) return false; return true; } bool wasm::DecodeFunctionSection(Decoder& d, const SigWithIdVector& sigs, size_t numImportedFunc, Uint32Vector* funcSigIndexes) { uint32_t sectionStart, sectionSize; if (!d.startSection(SectionId::Function, §ionStart, §ionSize, "function")) return false; if (sectionStart == Decoder::NotStarted) return true; uint32_t numDefs; if (!d.readVarU32(&numDefs)) return d.fail("expected number of function definitions"); CheckedInt numFuncs = numImportedFunc; numFuncs += numDefs; if (!numFuncs.isValid() || numFuncs.value() > MaxFuncs) return d.fail("too many functions"); if (!funcSigIndexes->reserve(numDefs)) return false; for (uint32_t i = 0; i < numDefs; i++) { uint32_t sigIndex; if (!DecodeSignatureIndex(d, sigs, &sigIndex)) return false; funcSigIndexes->infallibleAppend(sigIndex); } if (!d.finishSection(sectionStart, sectionSize, "function")) return false; return true; } bool wasm::EncodeLocalEntries(Encoder& e, const ValTypeVector& locals) { uint32_t numLocalEntries = 0; ValType prev = ValType(TypeCode::Limit); for (ValType t : locals) { if (t != prev) { numLocalEntries++; prev = t; } } if (!e.writeVarU32(numLocalEntries)) return false; if (numLocalEntries) { prev = locals[0]; uint32_t count = 1; for (uint32_t i = 1; i < locals.length(); i++, count++) { if (prev != locals[i]) { if (!e.writeVarU32(count)) return false; if (!e.writeValType(prev)) return false; prev = locals[i]; count = 0; } } if (!e.writeVarU32(count)) return false; if (!e.writeValType(prev)) return false; } return true; } bool wasm::DecodeLocalEntries(Decoder& d, ModuleKind kind, ValTypeVector* locals) { uint32_t numLocalEntries; if (!d.readVarU32(&numLocalEntries)) return d.fail("failed to read number of local entries"); for (uint32_t i = 0; i < numLocalEntries; i++) { uint32_t count; if (!d.readVarU32(&count)) return d.fail("failed to read local entry count"); if (MaxLocals - locals->length() < count) return d.fail("too many locals"); ValType type; if (!DecodeValType(d, kind, &type)) return false; if (!locals->appendN(type, count)) return false; } return true; } bool wasm::DecodeGlobalType(Decoder& d, ValType* type, bool* isMutable) { if (!DecodeValType(d, ModuleKind::Wasm, type)) return false; uint32_t flags; if (!d.readVarU32(&flags)) return d.fail("expected global flags"); if (flags & ~uint32_t(GlobalTypeImmediate::AllowedMask)) return d.fail("unexpected bits set in global flags"); *isMutable = flags & uint32_t(GlobalTypeImmediate::IsMutable); return true; } bool wasm::DecodeInitializerExpression(Decoder& d, const GlobalDescVector& globals, ValType expected, InitExpr* init) { uint16_t op; if (!d.readOp(&op)) return d.fail("failed to read initializer type"); switch (op) { case uint16_t(Op::I32Const): { int32_t i32; if (!d.readVarS32(&i32)) return d.fail("failed to read initializer i32 expression"); *init = InitExpr(Val(uint32_t(i32))); break; } case uint16_t(Op::I64Const): { int64_t i64; if (!d.readVarS64(&i64)) return d.fail("failed to read initializer i64 expression"); *init = InitExpr(Val(uint64_t(i64))); break; } case uint16_t(Op::F32Const): { RawF32 f32; if (!d.readFixedF32(&f32)) return d.fail("failed to read initializer f32 expression"); *init = InitExpr(Val(f32)); break; } case uint16_t(Op::F64Const): { RawF64 f64; if (!d.readFixedF64(&f64)) return d.fail("failed to read initializer f64 expression"); *init = InitExpr(Val(f64)); break; } case uint16_t(Op::GetGlobal): { uint32_t i; if (!d.readVarU32(&i)) return d.fail("failed to read get_global index in initializer expression"); if (i >= globals.length()) return d.fail("global index out of range in initializer expression"); if (!globals[i].isImport() || globals[i].isMutable()) return d.fail("initializer expression must reference a global immutable import"); *init = InitExpr(i, globals[i].type()); break; } default: { return d.fail("unexpected initializer expression"); } } if (expected != init->type()) return d.fail("type mismatch: initializer type and expected type don't match"); uint16_t end; if (!d.readOp(&end) || end != uint16_t(Op::End)) return d.fail("failed to read end of initializer expression"); return true; } bool wasm::DecodeLimits(Decoder& d, Limits* limits) { uint32_t flags; if (!d.readVarU32(&flags)) return d.fail("expected flags"); if (flags & ~uint32_t(0x1)) return d.fail("unexpected bits set in flags: %" PRIu32, (flags & ~uint32_t(0x1))); if (!d.readVarU32(&limits->initial)) return d.fail("expected initial length"); if (flags & 0x1) { uint32_t maximum; if (!d.readVarU32(&maximum)) return d.fail("expected maximum length"); if (limits->initial > maximum) { return d.fail("memory size minimum must not be greater than maximum; " "maximum length %" PRIu32 " is less than initial length %" PRIu32, maximum, limits->initial); } limits->maximum.emplace(maximum); } return true; } bool wasm::DecodeDataSection(Decoder& d, bool usesMemory, uint32_t minMemoryByteLength, const GlobalDescVector& globals, DataSegmentVector* segments) { uint32_t sectionStart, sectionSize; if (!d.startSection(SectionId::Data, §ionStart, §ionSize, "data")) return false; if (sectionStart == Decoder::NotStarted) return true; if (!usesMemory) return d.fail("data section requires a memory section"); uint32_t numSegments; if (!d.readVarU32(&numSegments)) return d.fail("failed to read number of data segments"); if (numSegments > MaxDataSegments) return d.fail("too many data segments"); for (uint32_t i = 0; i < numSegments; i++) { uint32_t linearMemoryIndex; if (!d.readVarU32(&linearMemoryIndex)) return d.fail("expected linear memory index"); if (linearMemoryIndex != 0) return d.fail("linear memory index must currently be 0"); DataSegment seg; if (!DecodeInitializerExpression(d, globals, ValType::I32, &seg.offset)) return false; if (!d.readVarU32(&seg.length)) return d.fail("expected segment size"); seg.bytecodeOffset = d.currentOffset(); if (!d.readBytes(seg.length)) return d.fail("data segment shorter than declared"); if (!segments->append(seg)) return false; } if (!d.finishSection(sectionStart, sectionSize, "data")) return false; return true; } bool wasm::DecodeMemoryLimits(Decoder& d, bool hasMemory, Limits* memory) { if (hasMemory) return d.fail("already have default memory"); if (!DecodeLimits(d, memory)) return false; CheckedInt initialBytes = memory->initial; initialBytes *= PageSize; if (!initialBytes.isValid() || initialBytes.value() > uint32_t(INT32_MAX)) return d.fail("initial memory size too big"); memory->initial = initialBytes.value(); if (memory->maximum) { CheckedInt maximumBytes = *memory->maximum; maximumBytes *= PageSize; if (!maximumBytes.isValid()) return d.fail("maximum memory size too big"); memory->maximum = Some(maximumBytes.value()); } return true; } bool wasm::DecodeMemorySection(Decoder& d, bool hasMemory, Limits* memory, bool *present) { *present = false; uint32_t sectionStart, sectionSize; if (!d.startSection(SectionId::Memory, §ionStart, §ionSize, "memory")) return false; if (sectionStart == Decoder::NotStarted) return true; *present = true; uint32_t numMemories; if (!d.readVarU32(&numMemories)) return d.fail("failed to read number of memories"); if (numMemories != 1) return d.fail("the number of memories must be exactly one"); if (!DecodeMemoryLimits(d, hasMemory, memory)) return false; if (!d.finishSection(sectionStart, sectionSize, "memory")) return false; return true; } bool wasm::DecodeUnknownSections(Decoder& d) { while (!d.done()) { if (!d.skipUserDefinedSection()) return false; } return true; } bool Decoder::fail(const char* msg, ...) { va_list ap; va_start(ap, msg); UniqueChars str(JS_vsmprintf(msg, ap)); va_end(ap); if (!str) return false; return fail(Move(str)); } bool Decoder::fail(UniqueChars msg) { MOZ_ASSERT(error_); UniqueChars strWithOffset(JS_smprintf("at offset %" PRIuSIZE ": %s", currentOffset(), msg.get())); if (!strWithOffset) return false; *error_ = Move(strWithOffset); return false; }