FLANG

preprocessor.h
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 "token-sequence.h"
19 #include "flang/Parser/char-block.h"
20 #include "flang/Parser/provenance.h"
21 #include <cstddef>
22 #include <list>
23 #include <stack>
24 #include <string>
25 #include <unordered_map>
26 #include <vector>
27
28 namespace Fortran::parser {
29
30 class Prescanner;
31
32 // Defines a macro
33 class Definition {
34 public:
35 Definition(const TokenSequence &, std::size_t firstToken, std::size_t tokens);
36 Definition(const std::vector<std::string> &argNames, const TokenSequence &,
37 std::size_t firstToken, std::size_t tokens, bool isVariadic = false);
38 Definition(const std::string &predefined, AllSources &);
39
40 bool isFunctionLike() const { return isFunctionLike_; }
41 std::size_t argumentCount() const { return argumentCount_; }
42 bool isVariadic() const { return isVariadic_; }
43 bool isDisabled() const { return isDisabled_; }
44 bool isPredefined() const { return isPredefined_; }
45 const TokenSequence &replacement() const { return replacement_; }
46
47 bool set_isDisabled(bool disable);
48
49 TokenSequence Apply(const std::vector<TokenSequence> &args, AllSources &);
50
51 private:
52 static TokenSequence Tokenize(const std::vector<std::string> &argNames,
53 const TokenSequence &token, std::size_t firstToken, std::size_t tokens);
54
55 bool isFunctionLike_{false};
56 std::size_t argumentCount_{0};
57 bool isVariadic_{false};
58 bool isDisabled_{false};
59 bool isPredefined_{false};
60 TokenSequence replacement_;
61 };
62
63 // Preprocessing state
64 class Preprocessor {
65 public:
66 explicit Preprocessor(AllSources &);
67
68 void Define(std::string macro, std::string value);
69 void Undefine(std::string macro);
70
71 std::optional<TokenSequence> MacroReplacement(
72 const TokenSequence &, const Prescanner &);
73
74 // Implements a preprocessor directive.
75 void Directive(const TokenSequence &, Prescanner *);
76
77 private:
78 enum class IsElseActive { No, Yes };
79 enum class CanDeadElseAppear { No, Yes };
80
81 CharBlock SaveTokenAsName(const CharBlock &);
82 bool IsNameDefined(const CharBlock &);
83 TokenSequence ReplaceMacros(const TokenSequence &, const Prescanner &);
84 void SkipDisabledConditionalCode(
85 const std::string &, IsElseActive, Prescanner *, ProvenanceRange);
86 bool IsIfPredicateTrue(const TokenSequence &expr, std::size_t first,
87 std::size_t exprTokens, Prescanner *);
88
89 AllSources &allSources_;
90 std::list<std::string> names_;
91 std::unordered_map<CharBlock, Definition> definitions_;
92 std::stack<CanDeadElseAppear> ifStack_;
93 };
94 } // namespace Fortran::parser
95 #endif // FORTRAN_PARSER_PREPROCESSOR_H_
Fortran::parser::Definition
Definition: preprocessor.h:33
Fortran::parser::AllSources
Definition: provenance.h:137
Fortran::parser::Prescanner
Definition: prescan.h:34
Fortran::parser::TokenSequence
Definition: token-sequence.h:32
Fortran::parser::CharBlock
Definition: char-block.h:28
Fortran::common::Interval< Provenance >
Fortran::parser
Definition: check-expression.h:19
Fortran::parser::Preprocessor
Definition: preprocessor.h:64