[PATCH] D42776: [Sema] Fix an assertion failure in constant expression evaluation of calls to functions with default arguments

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith accepted this revision.
rsmith added a comment.
This revision is now accepted and ready to land.

I think this can be cleaned up a bit further, but I'm fine with that happening after the patch lands. Thanks!



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Comment at: lib/AST/ExprConstant.cpp:455-456
     // values are stable.
-    typedef std::map<const void*, APValue> MapTy;
-    typedef MapTy::const_iterator temp_iterator;
+    typedef std::map<unsigned, APValue> VersionToValueMap;
+    typedef std::map<const void *, VersionToValueMap> MapTy;
     /// Temporaries - Temporary lvalues materialized within this stack frame.
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Have you considered using a pair<const void*, unsigned> as the key rather than a map-of-maps? It'd be preferable to only allocate one heap node rather than two for the (hopefully common) case where there is only one version of an object.


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Comment at: lib/AST/ExprConstant.cpp:466
 
+    /// The stack of integers for tracking version numbers for temporaries.
+    SmallVector<unsigned, 2> TempVersionStack = {1};
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If we're using this for variables in loops too, we should generalize the name and the description to not talk about temporaries.


https://reviews.llvm.org/D42776