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//===-- lib/Parser/preprocessor.h -------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// A Fortran-aware preprocessing module used by the prescanner to implement
// preprocessing directives and macro replacement. Intended to be efficient
// enough to always run on all source files even when no preprocessing is
// performed, so that special compiler command options &/or source file name
// extensions for preprocessing will not be necessary.
#include "token-sequence.h"
#include "flang/Parser/char-block.h"
#include "flang/Parser/provenance.h"
#include <cstddef>
#include <list>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>
namespace Fortran::parser {
class Prescanner;
class Preprocessor;
// Defines a macro
class Definition {
Definition(const TokenSequence &, std::size_t firstToken, std::size_t tokens);
Definition(const std::vector<std::string> &argNames, const TokenSequence &,
std::size_t firstToken, std::size_t tokens, bool isVariadic = false);
Definition(const std::string &predefined, AllSources &);
bool isFunctionLike() const { return isFunctionLike_; }
std::size_t argumentCount() const { return argumentCount_; }
bool isVariadic() const { return isVariadic_; }
bool isDisabled() const { return isDisabled_; }
bool isPredefined() const { return isPredefined_; }
const TokenSequence &replacement() const { return replacement_; }
bool set_isDisabled(bool disable);
TokenSequence Apply(const std::vector<TokenSequence> &args, Prescanner &);
static TokenSequence Tokenize(const std::vector<std::string> &argNames,
const TokenSequence &token, std::size_t firstToken, std::size_t tokens);
bool isFunctionLike_{false};
std::size_t argumentCount_{0};
bool isVariadic_{false};
bool isDisabled_{false};
bool isPredefined_{false};
TokenSequence replacement_;
// Preprocessing state
class Preprocessor {
explicit Preprocessor(AllSources &);
const AllSources &allSources() const { return allSources_; }
AllSources &allSources() { return allSources_; }
void DefineStandardMacros();
void Define(std::string macro, std::string value);
void Undefine(std::string macro);
bool IsNameDefined(const CharBlock &);
std::optional<TokenSequence> MacroReplacement(
const TokenSequence &, Prescanner &);
// Implements a preprocessor directive.
void Directive(const TokenSequence &, Prescanner &);
enum class IsElseActive { No, Yes };
enum class CanDeadElseAppear { No, Yes };
CharBlock SaveTokenAsName(const CharBlock &);
TokenSequence ReplaceMacros(const TokenSequence &, Prescanner &);
void SkipDisabledConditionalCode(
const std::string &, IsElseActive, Prescanner &, ProvenanceRange);
bool IsIfPredicateTrue(const TokenSequence &expr, std::size_t first,
std::size_t exprTokens, Prescanner &);
AllSources &allSources_;
std::list<std::string> names_;
std::unordered_map<CharBlock, Definition> definitions_;
std::stack<CanDeadElseAppear> ifStack_;
} // namespace Fortran::parser