1 files changed, 75 insertions, 0 deletions
diff --git a/include/clang/AST/CurrentSourceLocExprScope.h b/include/clang/AST/CurrentSourceLocExprScope.h
new file mode 100644
index 000000000000..4ebbdf63abb5
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+++ b/include/clang/AST/CurrentSourceLocExprScope.h
@@ -0,0 +1,75 @@
+//===--- CurrentSourceLocExprScope.h ----------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines types used to track the current context needed to evaluate
+//  a SourceLocExpr.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_CURRENT_SOURCE_LOC_EXPR_SCOPE_H
+#define LLVM_CLANG_AST_CURRENT_SOURCE_LOC_EXPR_SCOPE_H
+
+#include <cassert>
+
+namespace clang {
+class Expr;
+
+/// Represents the current source location and context used to determine the
+/// value of the source location builtins (ex. __builtin_LINE), including the
+/// context of default argument and default initializer expressions.
+class CurrentSourceLocExprScope {
+  /// The CXXDefaultArgExpr or CXXDefaultInitExpr we're currently evaluating.
+  const Expr *DefaultExpr = nullptr;
+
+public:
+  /// A RAII style scope guard used for tracking the current source
+  /// location and context as used by the source location builtins
+  /// (ex. __builtin_LINE).
+  class SourceLocExprScopeGuard;
+
+  const Expr *getDefaultExpr() const { return DefaultExpr; }
+
+  explicit CurrentSourceLocExprScope() = default;
+
+private:
+  explicit CurrentSourceLocExprScope(const Expr *DefaultExpr)
+      : DefaultExpr(DefaultExpr) {}
+
+  CurrentSourceLocExprScope(CurrentSourceLocExprScope const &) = default;
+  CurrentSourceLocExprScope &
+  operator=(CurrentSourceLocExprScope const &) = default;
+};
+
+class CurrentSourceLocExprScope::SourceLocExprScopeGuard {
+public:
+  SourceLocExprScopeGuard(const Expr *DefaultExpr,
+                          CurrentSourceLocExprScope &Current)
+      : Current(Current), OldVal(Current), Enable(false) {
+    assert(DefaultExpr && "the new scope should not be empty");
+    if ((Enable = (Current.getDefaultExpr() == nullptr)))
+      Current = CurrentSourceLocExprScope(DefaultExpr);
+  }
+
+  ~SourceLocExprScopeGuard() {
+    if (Enable)
+      Current = OldVal;
+  }
+
+private:
+  SourceLocExprScopeGuard(SourceLocExprScopeGuard const &) = delete;
+  SourceLocExprScopeGuard &operator=(SourceLocExprScopeGuard const &) = delete;
+
+  CurrentSourceLocExprScope &Current;
+  CurrentSourceLocExprScope OldVal;
+  bool Enable;
+};
+
+} // end namespace clang
+
+#endif // LLVM_CLANG_AST_CURRENT_SOURCE_LOC_EXPR_SCOPE_H