[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, 13 insertions, 0 deletions

diff --git a/clang/unittests/AST/ASTContextParentMapTest.cpp b/clang/unittests/AST/ASTContextParentMapTest.cpp
index 94e9735654c..b1d7db4164e 100644
--- a/clang/unittests/AST/ASTContextParentMapTest.cpp
+++ b/clang/unittests/AST/ASTContextParentMapTest.cpp
@@ -38,6 +38,19 @@ TEST(GetParents, ReturnsParentForStmt) {
                              ifStmt(hasParent(compoundStmt()))));
 }
 
+TEST(GetParents, ReturnsParentForTypeLoc) {
+  MatchVerifier<TypeLoc> Verifier;
+  EXPECT_TRUE(
+      Verifier.match("namespace a { class b {}; } void f(a::b) {}",
+                     typeLoc(hasParent(typeLoc(hasParent(functionDecl()))))));
+}
+
+TEST(GetParents, ReturnsParentForNestedNameSpecifierLoc) {
+  MatchVerifier<NestedNameSpecifierLoc> Verifier;
+  EXPECT_TRUE(Verifier.match("namespace a { class b {}; } void f(a::b) {}",
+                             nestedNameSpecifierLoc(hasParent(typeLoc()))));
+}
+
 TEST(GetParents, ReturnsParentInsideTemplateInstantiations) {
   MatchVerifier<Decl> DeclVerifier;
   EXPECT_TRUE(DeclVerifier.match(