[mangle] Fix mangling where an extra mangle context is required.

Summary:
- [Itanium C++ ABI][1], for certain contexts like default parameter and
  etc., mangling numbering will be local to the particular argument in
  which it appears.
- However, for these cases, the mangle numbering context is allocated per
  expression evaluation stack entry. That causes, for example, two
  lambdas defined/used understand the same default parameter are
  numbered as the same value and, in turn, one of them is not generated
  at all.
- In this patch, an extra mangle numbering context map is maintained in
  the AST context to map taht extra declaration context to its numbering
  context. So that, 2 different lambdas defined/used in the same default
  parameter are numbered differently.

[1]: https://itanium-cxx-abi.github.io/cxx-abi/abi.html

Reviewers: rsmith, eli.friedman

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68715

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374200 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 13 deletions

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index c9211eb700..2fb3e32e1b 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1045,13 +1045,6 @@ public:
     /// suffice, e.g., in a default function argument.
     Decl *ManglingContextDecl;
 
-    /// The context information used to mangle lambda expressions
-    /// and block literals within this context.
-    ///
-    /// This mangling information is allocated lazily, since most contexts
-    /// do not have lambda expressions or block literals.
-    std::unique_ptr<MangleNumberingContext> MangleNumbering;
-
     /// If we are processing a decltype type, a set of call expressions
     /// for which we have deferred checking the completeness of the return type.
     SmallVector<CallExpr *, 8> DelayedDecltypeCalls;
@@ -1080,12 +1073,7 @@ public:
                                       ExpressionKind ExprContext)
         : Context(Context), ParentCleanup(ParentCleanup),
           NumCleanupObjects(NumCleanupObjects), NumTypos(0),
-          ManglingContextDecl(ManglingContextDecl), MangleNumbering(),
-          ExprContext(ExprContext) {}
-
-    /// Retrieve the mangling numbering context, used to consistently
-    /// number constructs like lambdas for mangling.
-    MangleNumberingContext &getMangleNumberingContext(ASTContext &Ctx);
+          ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext) {}
 
     bool isUnevaluated() const {
       return Context == ExpressionEvaluationContext::Unevaluated ||