[AST] Re-add TypeLocs and NestedNameSpecifierLocs to the ParentMap.

This relands r250831 after some fixes to shrink the ParentMap overall
with one addtional tweak: nodes with pointer identity (e.g. Decl* and
friends) can be store more efficiently so I put them in a separate map.
All other nodes (so far only TypeLoc and NNSLoc) go in a different map
keyed on DynTypedNode. This further uglifies the code but significantly
reduces memory overhead.

Overall this change still make ParentMap significantly larger but it's
nowhere as bad as before. I see about 25 MB over baseline (pre-r251008)
on X86ISelLowering.cpp. If this becomes an issue we could consider
splitting the maps further as DynTypedNode is still larger (32 bytes)
than a single TypeLoc (16 bytes) but I didn't want to introduce even
more complexity now.

Differential Revision: http://reviews.llvm.org/D14011

llvm-svn: 251101

1 files changed, 4 insertions, 3 deletions

diff --git a/clang/lib/ASTMatchers/ASTMatchFinder.cpp b/clang/lib/ASTMatchers/ASTMatchFinder.cpp
index 8807b13c5ed..571e7dac240 100644
--- a/clang/lib/ASTMatchers/ASTMatchFinder.cpp
+++ b/clang/lib/ASTMatchers/ASTMatchFinder.cpp
@@ -621,9 +621,6 @@ private:
     if (Node.get<TranslationUnitDecl>() ==
         ActiveASTContext->getTranslationUnitDecl())
       return false;
-    assert(Node.getMemoizationData() &&
-           "Invariant broken: only nodes that support memoization may be "
-           "used in the parent map.");
 
     MatchKey Key;
     Key.MatcherID = Matcher.getID();
@@ -867,7 +864,11 @@ bool MatchASTVisitor::TraverseNestedNameSpecifier(NestedNameSpecifier *NNS) {
 
 bool MatchASTVisitor::TraverseNestedNameSpecifierLoc(
     NestedNameSpecifierLoc NNS) {
+  if (!NNS)
+    return true;
+
   match(NNS);
+
   // We only match the nested name specifier here (as opposed to traversing it)
   // because the traversal is already done in the parallel "Loc"-hierarchy.
   if (NNS.hasQualifier())