1 /* 2 * Copyright 2017 WebAssembly Community Group participants 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef wasm_support_name_h 18 #define wasm_support_name_h 19 20 #include <string> 21 22 #include "emscripten-optimizer/istring.h" 23 24 namespace wasm { 25 26 // We use a Name for all of the identifiers. These are IStrings, so they are 27 // all interned - comparisons etc are just pointer comparisons, so there is no 28 // perf loss. Having names everywhere makes using the AST much nicer (for 29 // example, block names are strings and not offsets, which makes composition 30 // - adding blocks, removing blocks - easy). One exception is local variables, 31 // where we do use indices, as they are a large proportion of the AST, 32 // perf matters a lot there, and compositionality is not a problem. 33 // TODO: as an optimization, IString values < some threshold could be considered 34 // numerical indices directly. 35 36 struct Name : public cashew::IString { NameName37 Name() : cashew::IString() {} NameName38 Name(const char* str) : cashew::IString(str, false) {} NameName39 Name(cashew::IString str) : cashew::IString(str) {} NameName40 Name(const std::string& str) : cashew::IString(str.c_str(), false) {} 41 42 friend std::ostream& operator<<(std::ostream& o, Name name) { 43 if (name.str) { 44 return o << name.str; 45 } else { 46 return o << "(null Name)"; 47 } 48 } 49 fromIntName50 static Name fromInt(size_t i) { 51 return cashew::IString(std::to_string(i).c_str(), false); 52 } 53 hasSubstringName54 bool hasSubstring(cashew::IString substring) { 55 return strstr(c_str(), substring.c_str()) != nullptr; 56 } 57 }; 58 59 } // namespace wasm 60 61 namespace std { 62 63 template<> struct hash<wasm::Name> : hash<cashew::IString> {}; 64 65 } // namespace std 66 67 #endif // wasm_support_name_h 68