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| 1 | //===-- lib/Parser/preprocessor.h -------------------------------*- C++ -*-===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #ifndef FORTRAN_PARSER_PREPROCESSOR_H_ |
| 10 | #define FORTRAN_PARSER_PREPROCESSOR_H_ |
| 11 | |
| 12 | // A Fortran-aware preprocessing module used by the prescanner to implement |
| 13 | // preprocessing directives and macro replacement. Intended to be efficient |
| 14 | // enough to always run on all source files even when no preprocessing is |
| 15 | // performed, so that special compiler command options &/or source file name |
| 16 | // extensions for preprocessing will not be necessary. |
| 17 | |
| 18 | #include "flang/Parser/char-block.h" |
| 19 | #include "flang/Parser/provenance.h" |
| 20 | #include "flang/Parser/token-sequence.h" |
| 21 | #include "llvm/Support/raw_ostream.h" |
| 22 | #include <cstddef> |
| 23 | #include <list> |
| 24 | #include <stack> |
| 25 | #include <string> |
| 26 | #include <unordered_map> |
| 27 | #include <vector> |
| 28 | |
| 29 | namespace Fortran::parser { |
| 30 | |
| 31 | class Prescanner; |
| 32 | class Preprocessor; |
| 33 | |
| 34 | // Defines a macro |
| 35 | class Definition { |
| 36 | public: |
| 37 | Definition(const TokenSequence &, std::size_t firstToken, std::size_t tokens); |
| 38 | Definition(const std::vector<std::string> &argNames, const TokenSequence &, |
| 39 | std::size_t firstToken, std::size_t tokens, bool isVariadic = false); |
| 40 | Definition(const std::string &predefined, AllSources &); |
| 41 | |
| 42 | bool isFunctionLike() const { return isFunctionLike_; } |
| 43 | std::size_t argumentCount() const { return argNames_.size(); } |
| 44 | bool isVariadic() const { return isVariadic_; } |
| 45 | bool isDisabled() const { return isDisabled_; } |
| 46 | bool isPredefined() const { return isPredefined_; } |
| 47 | const TokenSequence &replacement() const { return replacement_; } |
| 48 | |
| 49 | bool set_isDisabled(bool disable); |
| 50 | |
| 51 | TokenSequence Apply(const std::vector<TokenSequence> &args, Prescanner &); |
| 52 | |
| 53 | void Print(llvm::raw_ostream &out, const char *macroName = "") const; |
| 54 | |
| 55 | private: |
| 56 | static TokenSequence Tokenize(const std::vector<std::string> &argNames, |
| 57 | const TokenSequence &token, std::size_t firstToken, std::size_t tokens); |
| 58 | // For a given token, return the index of the argument to which the token |
| 59 | // corresponds, or `argumentCount` if the token does not correspond to any |
| 60 | // argument. |
| 61 | std::size_t GetArgumentIndex(const CharBlock &token) const; |
| 62 | |
| 63 | bool isFunctionLike_{false}; |
| 64 | bool isVariadic_{false}; |
| 65 | bool isDisabled_{false}; |
| 66 | bool isPredefined_{false}; |
| 67 | std::vector<std::string> argNames_; |
| 68 | TokenSequence replacement_; |
| 69 | }; |
| 70 | |
| 71 | // Preprocessing state |
| 72 | class Preprocessor { |
| 73 | public: |
| 74 | explicit Preprocessor(AllSources &); |
| 75 | |
| 76 | const AllSources &allSources() const { return allSources_; } |
| 77 | AllSources &allSources() { return allSources_; } |
| 78 | |
| 79 | void DefineStandardMacros(); |
| 80 | void Define(const std::string ¯o, const std::string &value); |
| 81 | void Undefine(std::string macro); |
| 82 | bool IsNameDefined(const CharBlock &); |
| 83 | bool IsFunctionLikeDefinition(const CharBlock &); |
| 84 | |
| 85 | // When called with partialFunctionLikeMacro not null, MacroReplacement() |
| 86 | // and ReplaceMacros() handle an unclosed function-like macro reference |
| 87 | // by terminating macro replacement at the name of the FLM and returning |
| 88 | // its index in the result. This allows the recursive call sites in |
| 89 | // MacroReplacement to append any remaining tokens in their inputs to |
| 90 | // that result and try again. All other Fortran preprocessors share this |
| 91 | // behavior. |
| 92 | std::optional<TokenSequence> MacroReplacement(const TokenSequence &, |
| 93 | Prescanner &, |
| 94 | std::optional<std::size_t> *partialFunctionLikeMacro = nullptr); |
| 95 | |
| 96 | // Implements a preprocessor directive. |
| 97 | void Directive(const TokenSequence &, Prescanner &); |
| 98 | |
| 99 | void PrintMacros(llvm::raw_ostream &out) const; |
| 100 | |
| 101 | private: |
| 102 | enum class IsElseActive { No, Yes }; |
| 103 | enum class CanDeadElseAppear { No, Yes }; |
| 104 | |
| 105 | CharBlock SaveTokenAsName(const CharBlock &); |
| 106 | TokenSequence ReplaceMacros(const TokenSequence &, Prescanner &, |
| 107 | std::optional<std::size_t> *partialFunctionLikeMacro = nullptr); |
| 108 | void SkipDisabledConditionalCode( |
| 109 | const std::string &, IsElseActive, Prescanner &, ProvenanceRange); |
| 110 | bool IsIfPredicateTrue(const TokenSequence &expr, std::size_t first, |
| 111 | std::size_t exprTokens, Prescanner &); |
| 112 | void LineDirective(const TokenSequence &, std::size_t, Prescanner &); |
| 113 | |
| 114 | AllSources &allSources_; |
| 115 | std::list<std::string> names_; |
| 116 | std::unordered_map<CharBlock, Definition> definitions_; |
| 117 | std::stack<CanDeadElseAppear> ifStack_; |
| 118 | }; |
| 119 | } // namespace Fortran::parser |
| 120 | #endif // FORTRAN_PARSER_PREPROCESSOR_H_ |
| 121 |
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