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1 : // Copyright 2015 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #ifndef V8_WASM_MODULE_DECODER_H_
6 : #define V8_WASM_MODULE_DECODER_H_
7 :
8 : #include "src/globals.h"
9 : #include "src/wasm/function-body-decoder.h"
10 : #include "src/wasm/wasm-constants.h"
11 : #include "src/wasm/wasm-features.h"
12 : #include "src/wasm/wasm-module.h"
13 : #include "src/wasm/wasm-result.h"
14 :
15 : namespace v8 {
16 : namespace internal {
17 :
18 : class Counters;
19 :
20 : namespace wasm {
21 :
22 : struct CompilationEnv;
23 :
24 : inline bool IsValidSectionCode(uint8_t byte) {
25 1423057 : return kTypeSectionCode <= byte && byte <= kLastKnownModuleSection;
26 : }
27 :
28 : const char* SectionName(SectionCode code);
29 :
30 : using ModuleResult = Result<std::shared_ptr<WasmModule>>;
31 : using FunctionResult = Result<std::unique_ptr<WasmFunction>>;
32 : using FunctionOffsets = std::vector<std::pair<int, int>>;
33 : using FunctionOffsetsResult = Result<FunctionOffsets>;
34 :
35 : struct AsmJsOffsetEntry {
36 : int byte_offset;
37 : int source_position_call;
38 : int source_position_number_conversion;
39 : };
40 : using AsmJsOffsets = std::vector<std::vector<AsmJsOffsetEntry>>;
41 : using AsmJsOffsetsResult = Result<AsmJsOffsets>;
42 :
43 : struct LocalName {
44 : int local_index;
45 : WireBytesRef name;
46 : LocalName(int local_index, WireBytesRef name)
47 12 : : local_index(local_index), name(name) {}
48 : };
49 4 : struct LocalNamesPerFunction {
50 : int function_index;
51 : int max_local_index = -1;
52 : std::vector<LocalName> names;
53 : explicit LocalNamesPerFunction(int function_index)
54 4 : : function_index(function_index) {}
55 : };
56 40 : struct LocalNames {
57 : int max_function_index = -1;
58 : std::vector<LocalNamesPerFunction> names;
59 : };
60 :
61 : // Decodes the bytes of a wasm module between {module_start} and {module_end}.
62 : V8_EXPORT_PRIVATE ModuleResult DecodeWasmModule(
63 : const WasmFeatures& enabled, const byte* module_start,
64 : const byte* module_end, bool verify_functions, ModuleOrigin origin,
65 : Counters* counters, AccountingAllocator* allocator);
66 :
67 : // Exposed for testing. Decodes a single function signature, allocating it
68 : // in the given zone. Returns {nullptr} upon failure.
69 : V8_EXPORT_PRIVATE FunctionSig* DecodeWasmSignatureForTesting(
70 : const WasmFeatures& enabled, Zone* zone, const byte* start,
71 : const byte* end);
72 :
73 : // Decodes the bytes of a wasm function between
74 : // {function_start} and {function_end}.
75 : V8_EXPORT_PRIVATE FunctionResult DecodeWasmFunctionForTesting(
76 : const WasmFeatures& enabled, Zone* zone, const ModuleWireBytes& wire_bytes,
77 : const WasmModule* module, const byte* function_start,
78 : const byte* function_end, Counters* counters);
79 :
80 : V8_EXPORT_PRIVATE WasmInitExpr DecodeWasmInitExprForTesting(
81 : const WasmFeatures& enabled, const byte* start, const byte* end);
82 :
83 : struct CustomSectionOffset {
84 : WireBytesRef section;
85 : WireBytesRef name;
86 : WireBytesRef payload;
87 : };
88 :
89 : V8_EXPORT_PRIVATE std::vector<CustomSectionOffset> DecodeCustomSections(
90 : const byte* start, const byte* end);
91 :
92 : // Extracts the mapping from wasm byte offset to asm.js source position per
93 : // function.
94 : // Returns a vector of vectors with <byte_offset, source_position> entries, or
95 : // failure if the wasm bytes are detected as invalid. Note that this validation
96 : // is not complete.
97 : AsmJsOffsetsResult DecodeAsmJsOffsets(const byte* module_start,
98 : const byte* module_end);
99 :
100 : // Decode the function names from the name section.
101 : // Returns the result as an unordered map. Only names with valid utf8 encoding
102 : // are stored and conflicts are resolved by choosing the last name read.
103 : void DecodeFunctionNames(const byte* module_start, const byte* module_end,
104 : std::unordered_map<uint32_t, WireBytesRef>* names);
105 :
106 : // Decode the local names assignment from the name section.
107 : // Stores the result in the given {LocalNames} structure. The result will be
108 : // empty if no name section is present. On encountering an error in the name
109 : // section, returns all information decoded up to the first error.
110 : void DecodeLocalNames(const byte* module_start, const byte* module_end,
111 : LocalNames* result);
112 :
113 : class ModuleDecoderImpl;
114 :
115 904 : class ModuleDecoder {
116 : public:
117 : explicit ModuleDecoder(const WasmFeatures& enabled);
118 : ~ModuleDecoder();
119 :
120 : void StartDecoding(Counters* counters, AccountingAllocator* allocator,
121 : ModuleOrigin origin = ModuleOrigin::kWasmOrigin);
122 :
123 : void DecodeModuleHeader(Vector<const uint8_t> bytes, uint32_t offset);
124 :
125 : void DecodeSection(SectionCode section_code, Vector<const uint8_t> bytes,
126 : uint32_t offset, bool verify_functions = true);
127 :
128 : bool CheckFunctionsCount(uint32_t functions_count, uint32_t offset);
129 :
130 : void DecodeFunctionBody(uint32_t index, uint32_t size, uint32_t offset,
131 : bool verify_functions = true);
132 :
133 : ModuleResult FinishDecoding(bool verify_functions = true);
134 :
135 : const std::shared_ptr<WasmModule>& shared_module() const;
136 508 : WasmModule* module() const { return shared_module().get(); }
137 :
138 : bool ok();
139 :
140 : // Translates the unknown section that decoder is pointing to to an extended
141 : // SectionCode if the unknown section is known to decoder.
142 : // The decoder is expected to point after the section lenght and just before
143 : // the identifier string of the unknown section.
144 : // If a SectionCode other than kUnknownSectionCode is returned, the decoder
145 : // will point right after the identifier string. Otherwise, the position is
146 : // undefined.
147 : static SectionCode IdentifyUnknownSection(Decoder& decoder, const byte* end);
148 :
149 : private:
150 : const WasmFeatures enabled_features_;
151 : std::unique_ptr<ModuleDecoderImpl> impl_;
152 : };
153 :
154 : } // namespace wasm
155 : } // namespace internal
156 : } // namespace v8
157 :
158 : #endif // V8_WASM_MODULE_DECODER_H_
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