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 #if !V8_ENABLE_WEBASSEMBLY 6 #error This header should only be included if WebAssembly is enabled. 7 #endif // !V8_ENABLE_WEBASSEMBLY 8 9 #ifndef V8_WASM_WASM_CONSTANTS_H_ 10 #define V8_WASM_WASM_CONSTANTS_H_ 11 12 #include <cstddef> 13 #include <cstdint> 14 15 #include "src/common/globals.h" 16 17 namespace v8 { 18 namespace internal { 19 namespace wasm { 20 21 // Binary encoding of the module header. 22 constexpr uint32_t kWasmMagic = 0x6d736100; 23 constexpr uint32_t kWasmVersion = 0x01; 24 25 // Binary encoding of value and heap types. 26 enum ValueTypeCode : uint8_t { 27 // Current value types 28 kVoidCode = 0x40, 29 kI32Code = 0x7f, 30 kI64Code = 0x7e, 31 kF32Code = 0x7d, 32 kF64Code = 0x7c, 33 // Simd proposal 34 kS128Code = 0x7b, 35 // GC proposal packed types 36 kI8Code = 0x7a, 37 kI16Code = 0x79, 38 // Current reference types 39 kFuncRefCode = 0x70, 40 kAnyRefCode = 0x6f, // aka externref 41 // typed-funcref and GC proposal types 42 // TODO(7748): For backwards compatibility only, remove when able. 43 kAnyRefCodeAlias = 0x6e, 44 kEqRefCode = 0x6d, 45 kOptRefCode = 0x6c, 46 kRefCode = 0x6b, 47 kI31RefCode = 0x6a, 48 // TODO(7748): Only here for backwards compatibility, remove when able. 49 kRttWithDepthCode = 0x69, 50 kRttCode = 0x68, 51 kDataRefCode = 0x67, 52 kArrayRefCode = 0x66 53 }; 54 55 // Binary encoding of type definitions. 56 constexpr uint8_t kWasmFunctionTypeCode = 0x60; 57 constexpr uint8_t kWasmStructTypeCode = 0x5f; 58 constexpr uint8_t kWasmArrayTypeCode = 0x5e; 59 constexpr uint8_t kWasmFunctionNominalCode = 0x5d; 60 constexpr uint8_t kWasmStructNominalCode = 0x5c; 61 constexpr uint8_t kWasmArrayNominalCode = 0x5b; 62 constexpr uint8_t kWasmSubtypeCode = 0x50; 63 constexpr uint8_t kWasmRecursiveTypeGroupCode = 0x4f; 64 65 // Binary encoding of import/export kinds. 66 enum ImportExportKindCode : uint8_t { 67 kExternalFunction = 0, 68 kExternalTable = 1, 69 kExternalMemory = 2, 70 kExternalGlobal = 3, 71 kExternalTag = 4 72 }; 73 74 enum LimitsFlags : uint8_t { 75 kNoMaximum = 0x00, // Also valid for table limits. 76 kWithMaximum = 0x01, // Also valid for table limits. 77 kSharedNoMaximum = 0x02, // Only valid for memory limits. 78 kSharedWithMaximum = 0x03, // Only valid for memory limits. 79 kMemory64NoMaximum = 0x04, // Only valid for memory limits. 80 kMemory64WithMaximum = 0x05 // Only valid for memory limits. 81 }; 82 83 // Flags for data and element segments. 84 enum SegmentFlags : uint8_t { 85 kActiveNoIndex = 0, // Active segment with a memory/table index of zero. 86 kPassive = 1, // Passive segment. 87 kActiveWithIndex = 2, // Active segment with a given memory/table index. 88 }; 89 90 // Binary encoding of sections identifiers. 91 enum SectionCode : int8_t { 92 kUnknownSectionCode = 0, // code for unknown sections 93 kTypeSectionCode = 1, // Function signature declarations 94 kImportSectionCode = 2, // Import declarations 95 kFunctionSectionCode = 3, // Function declarations 96 kTableSectionCode = 4, // Indirect function table and others 97 kMemorySectionCode = 5, // Memory attributes 98 kGlobalSectionCode = 6, // Global declarations 99 kExportSectionCode = 7, // Exports 100 kStartSectionCode = 8, // Start function declaration 101 kElementSectionCode = 9, // Elements section 102 kCodeSectionCode = 10, // Function code 103 kDataSectionCode = 11, // Data segments 104 kDataCountSectionCode = 12, // Number of data segments 105 kTagSectionCode = 13, // Tag section 106 107 // The following sections are custom sections, and are identified using a 108 // string rather than an integer. Their enumeration values are not guaranteed 109 // to be consistent. 110 kNameSectionCode, // Name section (encoded as a string) 111 kSourceMappingURLSectionCode, // Source Map URL section 112 kDebugInfoSectionCode, // DWARF section .debug_info 113 kExternalDebugInfoSectionCode, // Section encoding the external symbol path 114 kCompilationHintsSectionCode, // Compilation hints section 115 kBranchHintsSectionCode, // Branch hints section 116 117 // Helper values 118 kFirstSectionInModule = kTypeSectionCode, 119 kLastKnownModuleSection = kBranchHintsSectionCode, 120 kFirstUnorderedSection = kDataCountSectionCode, 121 }; 122 123 // Binary encoding of compilation hints. 124 constexpr uint8_t kDefaultCompilationHint = 0x0; 125 constexpr uint8_t kNoCompilationHint = kMaxUInt8; 126 127 // Binary encoding of name section kinds. 128 enum NameSectionKindCode : uint8_t { 129 kModuleCode = 0, 130 kFunctionCode = 1, 131 kLocalCode = 2, 132 // https://github.com/WebAssembly/extended-name-section/ 133 kLabelCode = 3, 134 kTypeCode = 4, 135 kTableCode = 5, 136 kMemoryCode = 6, 137 kGlobalCode = 7, 138 kElementSegmentCode = 8, 139 kDataSegmentCode = 9, 140 // https://github.com/WebAssembly/gc/issues/193 141 kFieldCode = 10 142 }; 143 144 constexpr size_t kWasmPageSize = 0x10000; 145 constexpr uint32_t kWasmPageSizeLog2 = 16; 146 static_assert(kWasmPageSize == size_t{1} << kWasmPageSizeLog2, "consistency"); 147 148 // TODO(wasm): Wrap WasmCodePosition in a struct. 149 using WasmCodePosition = int; 150 constexpr WasmCodePosition kNoCodePosition = -1; 151 152 constexpr uint32_t kExceptionAttribute = 0; 153 154 constexpr int kAnonymousFuncIndex = -1; 155 156 // The number of calls to an exported Wasm function that will be handled 157 // by the generic wrapper. Once the budget is exhausted, a specific wrapper 158 // is to be compiled for the function's signature. 159 // The abstract goal of the tiering strategy for the js-to-wasm wrappers is to 160 // use the generic wrapper as much as possible (less space, no need to compile), 161 // but fall back to compiling a specific wrapper for any function (signature) 162 // that is used often enough for the generic wrapper's small execution penalty 163 // to start adding up. 164 // So, when choosing a value for the initial budget, we are interested in a 165 // value that skips on tiering up functions that are called only a few times and 166 // the tier-up only wastes resources, but triggers compilation of specific 167 // wrappers early on for those functions that have the potential to be called 168 // often enough. 169 constexpr uint32_t kGenericWrapperBudget = 1000; 170 171 // The minimum length of supertype arrays for wasm-gc types. Having a size > 0 172 // gives up some module size for faster access to the supertypes. 173 constexpr uint32_t kMinimumSupertypeArraySize = 3; 174 175 #if V8_TARGET_ARCH_X64 176 constexpr int32_t kOSRTargetOffset = 5 * kSystemPointerSize; 177 #endif 178 179 constexpr Tagged_t kArrayInitFromDataArrayTooLargeErrorCode = 0; 180 constexpr Tagged_t kArrayInitFromDataSegmentOutOfBoundsErrorCode = 1; 181 182 } // namespace wasm 183 } // namespace internal 184 } // namespace v8 185 186 #endif // V8_WASM_WASM_CONSTANTS_H_ 187