LexerUtils.h

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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_LEXERUTILS_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_LEXERUTILS_H
 
#include "clang/AST/ASTContext.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/STLFunctionalExtras.h"
#include <optional>
#include <utility>
#include <vector>
 
namespace clang {
 
class Stmt;
 
namespace tidy::utils::lexer {
 
/// Returns previous token or ``std::nullopt`` if not found.
std::optional<Token> getPreviousToken(SourceLocation Location,
                                      const SourceManager &SM,
                                      const LangOptions &LangOpts,
                                      bool SkipComments = true);
 
std::pair<std::optional<Token>, SourceLocation>
getPreviousTokenAndStart(SourceLocation Location, const SourceManager &SM,
                         const LangOptions &LangOpts, bool SkipComments = true);
 
SourceLocation findPreviousTokenStart(SourceLocation Start,
                                      const SourceManager &SM,
                                      const LangOptions &LangOpts);
 
SourceLocation findPreviousTokenKind(SourceLocation Start,
                                     const SourceManager &SM,
                                     const LangOptions &LangOpts,
                                     tok::TokenKind TK);
 
SourceLocation findNextTerminator(SourceLocation Start, const SourceManager &SM,
                                  const LangOptions &LangOpts);
 
template <typename TokenKind, typename... TokenKinds>
SourceLocation findPreviousAnyTokenKind(SourceLocation Start,
                                        const SourceManager &SM,
                                        const LangOptions &LangOpts,
                                        TokenKind TK, TokenKinds... TKs) {
  if (Start.isInvalid() || Start.isMacroID())
    return {};
  while (true) {
    const SourceLocation L = findPreviousTokenStart(Start, SM, LangOpts);
    if (L.isInvalid() || L.isMacroID())
      return {};
 
    Token T;
    // Returning 'true' is used to signal failure to retrieve the token.
    if (Lexer::getRawToken(L, T, SM, LangOpts, /*IgnoreWhiteSpace=*/true))
      return {};
 
    if (T.isOneOf(TK, TKs...))
      return T.getLocation();
 
    Start = L;
  }
}
 
template <typename TokenKind, typename... TokenKinds>
SourceLocation findNextAnyTokenKind(SourceLocation Start,
                                    const SourceManager &SM,
                                    const LangOptions &LangOpts, TokenKind TK,
                                    TokenKinds... TKs) {
  while (true) {
    std::optional<Token> CurrentToken =
        Lexer::findNextToken(Start, SM, LangOpts);
 
    if (!CurrentToken)
      return {};
 
    const Token PotentialMatch = *CurrentToken;
    if (PotentialMatch.isOneOf(TK, TKs...))
      return PotentialMatch.getLocation();
 
    // If we reach the end of the file, and eof is not the target token, we stop
    // the loop, otherwise we will get infinite loop (findNextToken will return
    // eof on eof).
    if (PotentialMatch.is(tok::eof))
      return {};
    Start = PotentialMatch.getLastLoc();
  }
}
 
// Finds next token, possibly a comment.
inline std::optional<Token>
findNextTokenIncludingComments(SourceLocation Start, const SourceManager &SM,
                               const LangOptions &LangOpts) {
  return Lexer::findNextToken(Start, SM, LangOpts, true);
}
 
// Finds next token that's not a comment.
inline std::optional<Token>
findNextTokenSkippingComments(SourceLocation Start, const SourceManager &SM,
                              const LangOptions &LangOpts) {
  return Lexer::findNextToken(Start, SM, LangOpts, false);
}
 
/// Re-lex the provide \p Range and return \c false if either a macro spans
/// multiple tokens, a pre-processor directive or failure to retrieve the
/// next token is found, otherwise \c true.
bool rangeContainsExpansionsOrDirectives(SourceRange Range,
                                         const SourceManager &SM,
                                         const LangOptions &LangOpts);
 
// Represents a comment token and its source location in the original file.
struct CommentToken {
  SourceLocation Loc;
  StringRef Text;
};
 
/// Returns all comment tokens found in the given range.
std::vector<CommentToken> getCommentsInRange(CharSourceRange Range,
                                             const SourceManager &SM,
                                             const LangOptions &LangOpts);
 
/// Returns comment tokens found in the given range. If a non-comment token is
/// encountered, clears previously collected comments and continues.
std::vector<CommentToken>
getTrailingCommentsInRange(CharSourceRange Range, const SourceManager &SM,
                           const LangOptions &LangOpts);
 
/// Returns source range of the first token in \p Range matching \p Pred.
/// The returned char range starts at the matched token and ends at the start
/// of the next token. Returns invalid range if no token matches.
CharSourceRange
findTokenTextInRange(CharSourceRange Range, const SourceManager &SM,
                     const LangOptions &LangOpts,
                     llvm::function_ref<bool(const Token &)> Pred);
 
/// Assuming that ``Range`` spans a CVR-qualified type, returns the
/// token in ``Range`` that is responsible for the qualification. ``Range``
/// must be valid with respect to ``SM``.  Returns ``std::nullopt`` if no
/// qualifying tokens are found.
/// \note: doesn't support member function qualifiers.
std::optional<Token> getQualifyingToken(tok::TokenKind TK,
                                        CharSourceRange Range,
                                        const ASTContext &Context,
                                        const SourceManager &SM);
 
/// Stmt->getEndLoc does not always behave the same way depending on Token type.
/// See implementation for exceptions.
SourceLocation getUnifiedEndLoc(const Stmt &S, const SourceManager &SM,
                                const LangOptions &LangOpts);
 
/// For a given FunctionDecl returns the location where you would need to place
/// the noexcept specifier.
SourceLocation getLocationForNoexceptSpecifier(const FunctionDecl *FuncDecl,
                                               const SourceManager &SM);
 
} // namespace tidy::utils::lexer
} // namespace clang
 
#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_LEXERUTILS_H