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

This reverts r374268 (git commit c34385d07c7d59447bf836b740f032235391d121)

I think I reverted this by mistake, so I'm relanding it. While my bisect
found this revision, I think the crashes I'm seeing locally must be
environmental. Maybe the version of clang I'm using miscompiles tot
clang.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374269 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 6 insertions, 13 deletions

diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index 5105b9c35c..7547960b09 100644
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -514,6 +514,8 @@ private:
   /// need to be consistently numbered for the mangler).
   llvm::DenseMap<const DeclContext *, std::unique_ptr<MangleNumberingContext>>
       MangleNumberingContexts;
+  llvm::DenseMap<const Decl *, std::unique_ptr<MangleNumberingContext>>
+      ExtraMangleNumberingContexts;
 
   /// Side-table of mangling numbers for declarations which rarely
   /// need them (like static local vars).
@@ -2812,6 +2814,9 @@ public:
   /// Retrieve the context for computing mangling numbers in the given
   /// DeclContext.
   MangleNumberingContext &getManglingNumberContext(const DeclContext *DC);
+  enum NeedExtraManglingDecl_t { NeedExtraManglingDecl };
+  MangleNumberingContext &getManglingNumberContext(NeedExtraManglingDecl_t,
+                                                   const Decl *D);
 
   std::unique_ptr<MangleNumberingContext> createMangleNumberingContext() const;
 
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index b68da4b7f5..1cc6fc67bc 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 ||