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  1. //===--- CurrentSourceLocExprScope.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. //  This file defines types used to track the current context needed to evaluate
  10. //  a SourceLocExpr.
  11. //
  12. //===----------------------------------------------------------------------===//
  13.  
  14. #ifndef LLVM_CLANG_AST_CURRENTSOURCELOCEXPRSCOPE_H
  15. #define LLVM_CLANG_AST_CURRENTSOURCELOCEXPRSCOPE_H
  16.  
  17. #include <cassert>
  18.  
  19. namespace clang {
  20. class Expr;
  21.  
  22. /// Represents the current source location and context used to determine the
  23. /// value of the source location builtins (ex. __builtin_LINE), including the
  24. /// context of default argument and default initializer expressions.
  25. class CurrentSourceLocExprScope {
  26.   /// The CXXDefaultArgExpr or CXXDefaultInitExpr we're currently evaluating.
  27.   const Expr *DefaultExpr = nullptr;
  28.  
  29. public:
  30.   /// A RAII style scope guard used for tracking the current source
  31.   /// location and context as used by the source location builtins
  32.   /// (ex. __builtin_LINE).
  33.   class SourceLocExprScopeGuard;
  34.  
  35.   const Expr *getDefaultExpr() const { return DefaultExpr; }
  36.  
  37.   explicit CurrentSourceLocExprScope() = default;
  38.  
  39. private:
  40.   explicit CurrentSourceLocExprScope(const Expr *DefaultExpr)
  41.       : DefaultExpr(DefaultExpr) {}
  42.  
  43.   CurrentSourceLocExprScope(CurrentSourceLocExprScope const &) = default;
  44.   CurrentSourceLocExprScope &
  45.   operator=(CurrentSourceLocExprScope const &) = default;
  46. };
  47.  
  48. class CurrentSourceLocExprScope::SourceLocExprScopeGuard {
  49. public:
  50.   SourceLocExprScopeGuard(const Expr *DefaultExpr,
  51.                           CurrentSourceLocExprScope &Current)
  52.       : Current(Current), OldVal(Current), Enable(false) {
  53.     assert(DefaultExpr && "the new scope should not be empty");
  54.     if ((Enable = (Current.getDefaultExpr() == nullptr)))
  55.       Current = CurrentSourceLocExprScope(DefaultExpr);
  56.   }
  57.  
  58.   ~SourceLocExprScopeGuard() {
  59.     if (Enable)
  60.       Current = OldVal;
  61.   }
  62.  
  63. private:
  64.   SourceLocExprScopeGuard(SourceLocExprScopeGuard const &) = delete;
  65.   SourceLocExprScopeGuard &operator=(SourceLocExprScopeGuard const &) = delete;
  66.  
  67.   CurrentSourceLocExprScope &Current;
  68.   CurrentSourceLocExprScope OldVal;
  69.   bool Enable;
  70. };
  71.  
  72. } // end namespace clang
  73.  
  74. #endif // LLVM_CLANG_AST_CURRENTSOURCELOCEXPRSCOPE_H
  75.