1 // Copyright 2016 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_SIGNATURE_MAP_H_ 6 #define V8_WASM_SIGNATURE_MAP_H_ 7 8 #include <unordered_map> 9 10 #include "src/signature.h" 11 #include "src/wasm/value-type.h" 12 13 namespace v8 { 14 namespace internal { 15 16 namespace wasm { 17 18 using FunctionSig = Signature<ValueType>; 19 20 // A signature map canonicalizes signatures into a range of indices so that 21 // two different {FunctionSig} instances with the same contents map to the 22 // same index. 23 class V8_EXPORT_PRIVATE SignatureMap { 24 public: 25 // Allow default construction and move construction (because we have vectors 26 // of objects containing SignatureMaps), but disallow copy or assign. It's 27 // too easy to get security bugs by accidentally updating a copy of the map. 28 MOVE_ONLY_WITH_DEFAULT_CONSTRUCTORS(SignatureMap); 29 30 // Gets the index for a signature, assigning a new index if necessary. 31 uint32_t FindOrInsert(const FunctionSig& sig); 32 33 // Gets the index for a signature, returning {-1} if not found. 34 int32_t Find(const FunctionSig& sig) const; 35 36 // Disallows further insertions to this signature map. Freeze()37 void Freeze() { frozen_ = true; } 38 39 private: 40 uint32_t next_ = 0; 41 bool frozen_ = false; 42 std::unordered_map<FunctionSig, uint32_t, base::hash<FunctionSig>> map_; 43 }; 44 45 } // namespace wasm 46 } // namespace internal 47 } // namespace v8 48 49 #endif // V8_WASM_SIGNATURE_MAP_H_ 50