| 1 | /* |
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| 2 | * Copyright 2017 WebAssembly Community Group participants |
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| 3 | * |
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| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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| 5 | * you may not use this file except in compliance with the License. |
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| 6 | * You may obtain a copy of the License at |
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| 7 | * |
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| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 9 | * |
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| 10 | * Unless required by applicable law or agreed to in writing, software |
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| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 13 | * See the License for the specific language governing permissions and |
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| 14 | * limitations under the License. |
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| 15 | */ |
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| 16 | |
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| 17 | #ifndef wasm_support_name_h |
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| 18 | #define wasm_support_name_h |
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| 19 | |
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| 20 | #include "support/istring.h" |
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| 21 | |
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| 22 | namespace wasm { |
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| 23 | |
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| 24 | // We use a Name for all of the identifiers. These are IStrings, so they are |
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| 25 | // all interned - comparisons etc are just pointer comparisons, so there is no |
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| 26 | // perf loss. Having names everywhere makes using the AST much nicer (for |
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| 27 | // example, block names are strings and not offsets, which makes composition |
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| 28 | // - adding blocks, removing blocks - easy). One exception is local variables, |
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| 29 | // where we do use indices, as they are a large proportion of the AST, |
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| 30 | // perf matters a lot there, and compositionality is not a problem. |
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| 31 | // TODO: as an optimization, IString values < some threshold could be considered |
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| 32 | // numerical indices directly. |
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| 33 | |
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| 34 | struct Name : public IString { |
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| 35 | Name() : IString() {} |
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| 36 | Name(std::string_view str) : IString(str, false) {} |
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| 37 | Name(const char* str) : IString(str, false) {} |
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| 38 | Name(IString str) : IString(str) {} |
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| 39 | Name(const std::string& str) : IString(str) {} |
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| 40 | |
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| 41 | // String literals do not need to be copied. Note: Not safe to construct from |
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| 42 | // temporary char arrays! Take their address first. |
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| 43 | template<size_t N> Name(const char (&str)[N]) : IString(str) {} |
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| 44 | |
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| 45 | friend std::ostream& operator<<(std::ostream& o, Name name) { |
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| 46 | if (name) { |
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| 47 | return o << name.str; |
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| 48 | } else { |
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| 49 | return o << "(null Name)" ; |
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| 50 | } |
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| 51 | } |
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| 52 | |
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| 53 | static Name fromInt(size_t i) { |
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| 54 | return IString(std::to_string(i).c_str(), false); |
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| 55 | } |
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| 56 | |
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| 57 | bool hasSubstring(IString substring) { |
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| 58 | // TODO: Use C++23 `contains`. |
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| 59 | return str.find(substring.str) != std::string_view::npos; |
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| 60 | } |
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| 61 | }; |
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| 62 | |
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| 63 | } // namespace wasm |
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| 64 | |
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| 65 | namespace std { |
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| 66 | |
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| 67 | template<> struct hash<wasm::Name> : hash<wasm::IString> {}; |
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| 68 | |
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| 69 | } // namespace std |
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| 70 | |
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| 71 | #endif // wasm_support_name_h |
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| 72 | |
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