//===- clang/Lex/DependencyDirectivesSourceMinimizer.h -  ----------*- C++ -*-//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

///

/// \file

/// This is the interface for minimizing header and source files to the

/// minimum necessary preprocessor directives for evaluating includes. It

/// reduces the source down to #define, #include, #import, @import, and any

/// conditional preprocessor logic that contains one of those.

///

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LEX_DEPENDENCYDIRECTIVESSOURCEMINIMIZER_H

#define LLVM_CLANG_LEX_DEPENDENCYDIRECTIVESSOURCEMINIMIZER_H

#include "clang/Basic/SourceLocation.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/StringRef.h"

namespace clang {

class DiagnosticsEngine;

namespace minimize_source_to_dependency_directives {

/// Represents the kind of preprocessor directive or a module declaration that

/// is tracked by the source minimizer in its token output.

enum TokenKind {

  pp_none,

  pp_include,

  pp___include_macros,

  pp_define,

  pp_undef,

  pp_import,

  pp_pragma_import,

  pp_pragma_once,

  pp_pragma_push_macro,

  pp_pragma_pop_macro,

  pp_pragma_include_alias,

  pp_include_next,

  pp_if,

  pp_ifdef,

  pp_ifndef,

  pp_elif,

  pp_elifdef,

  pp_elifndef,

  pp_else,

  pp_endif,

  decl_at_import,

  cxx_export_decl,

  cxx_module_decl,

  cxx_import_decl,

  pp_eof,

};

/// Represents a simplified token that's lexed as part of the source

/// minimization. It's used to track the location of various preprocessor

/// directives that could potentially have an effect on the depedencies.

struct Token {

  /// The kind of token.

  TokenKind K = pp_none;

  /// Offset into the output byte stream of where the directive begins.

  int Offset = -1;

  Token(TokenKind K, int Offset) : K(K), Offset(Offset) {}

};

/// Simplified token range to track the range of a potentially skippable PP

/// directive.

struct SkippedRange {

  /// Offset into the output byte stream of where the skipped directive begins.

  int Offset;

  /// The number of bytes that can be skipped before the preprocessing must

  /// resume.

  int Length;

};

/// Computes the potential source ranges that can be skipped by the preprocessor

/// when skipping a directive like #if, #ifdef or #elsif.

///

/// \returns false on success, true on error.

bool computeSkippedRanges(ArrayRef<Token> Input,

                          llvm::SmallVectorImpl<SkippedRange> &Range);

} // end namespace minimize_source_to_dependency_directives

/// Minimize the input down to the preprocessor directives that might have

/// an effect on the dependencies for a compilation unit.

///

/// This function deletes all non-preprocessor code, and strips anything that

/// can't affect what gets included. It canonicalizes whitespace where

/// convenient to stabilize the output against formatting changes in the input.

///

/// Clears the output vectors at the beginning of the call.

///

/// \returns false on success, true on error. If the diagnostic engine is not

/// null, an appropriate error is reported using the given input location

/// with the offset that corresponds to the minimizer's current buffer offset.

bool minimizeSourceToDependencyDirectives(

    llvm::StringRef Input, llvm::SmallVectorImpl<char> &Output,

    llvm::SmallVectorImpl<minimize_source_to_dependency_directives::Token>

        &Tokens,

    DiagnosticsEngine *Diags = nullptr,

    SourceLocation InputSourceLoc = SourceLocation());

} // end namespace clang

#endif // LLVM_CLANG_LEX_DEPENDENCYDIRECTIVESSOURCEMINIMIZER_H