[clang] clang: Make the type_info builtin declaration a singleton (PR #151277)

[Erich Keane via cfe-commits]

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@@ -2381,6 +2384,15 @@ class ASTContext : public RefCountedBase<ASTContext> {
     return getTagDeclType(MSGuidTagDecl);
   }
 
+  /// Retrieve the implicitly-predeclared 'struct type_info' declaration.
+  TagDecl *getMSTypeInfoTagDecl() const {
+    // Lazily create this type on demand - it's only needed for MS builds.
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erichkeane wrote:

AFAIK: we can't do a static-local.  That ends up causing problems with multiple-loads of the AST/loading from serialization/etc.  

https://github.com/llvm/llvm-project/pull/151277