[libclang] Indexing: only index implicit template instantiations via an opt-in indexing option.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150517 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/Indexing.cpp b/tools/libclang/Indexing.cpp
index 0d6da28..d1af388 100644
--- a/tools/libclang/Indexing.cpp
+++ b/tools/libclang/Indexing.cpp
@@ -137,11 +137,17 @@
   virtual void HandleInterestingDecl(DeclGroupRef D) {}
 
   virtual void HandleTagDeclDefinition(TagDecl *D) {
+    if (!IndexCtx.shouldIndexImplicitTemplateInsts())
+      return;
+
     if (IndexCtx.isTemplateImplicitInstantiation(D))
       IndexCtx.indexDecl(D);
   }
 
   virtual void HandleCXXImplicitFunctionInstantiation(FunctionDecl *D) {
+    if (!IndexCtx.shouldIndexImplicitTemplateInsts())
+      return;
+
     IndexCtx.indexDecl(D);
   }
 };
@@ -194,7 +200,12 @@
     indexDiagnostics(CXTU, IndexCtx);
   }
 
-  virtual TranslationUnitKind getTranslationUnitKind() { return TU_Complete; }
+  virtual TranslationUnitKind getTranslationUnitKind() {
+    if (IndexCtx.shouldIndexImplicitTemplateInsts())
+      return TU_Complete;
+    else
+      return TU_Prefix;
+  }
   virtual bool hasCodeCompletionSupport() const { return false; }
 };