Don't leak TemplateIds when a plugin parses late-parsed templates at TU end.

In -fdelayed-template-parsing mode, templates that aren't used are not parsed
at all.  For some diagnostic plugins, this is a problem since they want to
analyse the contents of the template function body.  What has been suggested
on cfe-dev [1] is to explicitly parse interesting templates in
HandleTranslationUnit(); IWYU does this for example [2].

This is workable, but since the delayed parsing doesn't run below a call to
ParseTopLevelDecl(), no DestroyTemplateIdAnnotationsRAIIObj object is on the
stack to clean up TemplateIds that are created during parsing.  To fix this,
let ~Parser() clean them up in delayed template parsing mode instead of
leaking (or asserting in +Assert builds).

(r219810, relanded in r220400, fixed the same problem in incremental processing
mode; the review thread of r219810 has a good discussion of the problem.)

To test this, give the PrintFunctionNames plugin a flag to force parsing
of a template and add a test that uses it in -fdelayed-template-parsing mode.
Without the Parser.cpp change, that test asserts.

1: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-August/038415.html
2: https://code.google.com/p/include-what-you-use/source/detail?r=566 
llvm-svn: 237531

1 files changed, 29 insertions, 20 deletions

diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index a45eaa0e333..dea7a6998a2 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -38,6 +38,26 @@ public:
     return false;
   }
 };
+
+/// \brief RAIIObject to destroy the contents of a SmallVector of
+/// TemplateIdAnnotation pointers and clear the vector.
+class DestroyTemplateIdAnnotationsRAIIObj {
+  SmallVectorImpl<TemplateIdAnnotation *> &Container;
+
+public:
+  DestroyTemplateIdAnnotationsRAIIObj(
+      SmallVectorImpl<TemplateIdAnnotation *> &Container)
+      : Container(Container) {}
+
+  ~DestroyTemplateIdAnnotationsRAIIObj() {
+    for (SmallVectorImpl<TemplateIdAnnotation *>::iterator I =
+             Container.begin(),
+                                                           E = Container.end();
+         I != E; ++I)
+      (*I)->Destroy();
+    Container.clear();
+  }
+};
 } // end anonymous namespace
 
 IdentifierInfo *Parser::getSEHExceptKeyword() {
@@ -414,6 +434,15 @@ Parser::~Parser() {
 
   PP.clearCodeCompletionHandler();
 
+  if (getLangOpts().DelayedTemplateParsing &&
+      !PP.isIncrementalProcessingEnabled() && !TemplateIds.empty()) {
+    // If an ASTConsumer parsed delay-parsed templates in their
+    // HandleTranslationUnit() method, TemplateIds created there were not
+    // guarded by a DestroyTemplateIdAnnotationsRAIIObj object in
+    // ParseTopLevelDecl(). Destroy them here.
+    DestroyTemplateIdAnnotationsRAIIObj CleanupRAII(TemplateIds);
+  }
+
   assert(TemplateIds.empty() && "Still alive TemplateIdAnnotations around?");
 }
 
@@ -490,26 +519,6 @@ void Parser::Initialize() {
   ConsumeToken();
 }
 
-namespace {
-  /// \brief RAIIObject to destroy the contents of a SmallVector of
-  /// TemplateIdAnnotation pointers and clear the vector.
-  class DestroyTemplateIdAnnotationsRAIIObj {
-    SmallVectorImpl<TemplateIdAnnotation *> &Container;
-  public:
-    DestroyTemplateIdAnnotationsRAIIObj(SmallVectorImpl<TemplateIdAnnotation *>
-                                       &Container)
-      : Container(Container) {}
-
-    ~DestroyTemplateIdAnnotationsRAIIObj() {
-      for (SmallVectorImpl<TemplateIdAnnotation *>::iterator I =
-           Container.begin(), E = Container.end();
-           I != E; ++I)
-        (*I)->Destroy();
-      Container.clear();
-    }
-  };
-}
-
 void Parser::LateTemplateParserCleanupCallback(void *P) {
   // While this RAII helper doesn't bracket any actual work, the destructor will
   // clean up annotations that were created during ActOnEndOfTranslationUnit