Blink GC plugin: disallow pure-virtual trace methods.

tools/clang/blink_gc_plugin/RecordInfo.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "Config.h"
 #include "RecordInfo.h"
 
 using namespace clang;
 using std::string;
 
@@ skipping 254 matching lines @@
   DetermineTracingMethods();
   return finalize_dispatch_method_;
 }
 
 RecordInfo::Bases& RecordInfo::GetBases() {
   if (!bases_)
     bases_ = CollectBases();
   return *bases_;
 }
 
-bool RecordInfo::InheritsNonPureTrace() {
-  if (CXXMethodDecl* trace = GetTraceMethod())
-    return !trace->isPure();
+bool RecordInfo::InheritsTrace() {
+  if (GetTraceMethod())
+    return true;
   for (Bases::iterator it = GetBases().begin(); it != GetBases().end(); ++it) {
-    if (it->second.info()->InheritsNonPureTrace())
+    if (it->second.info()->InheritsTrace())
       return true;
   }
   return false;
 }
 
 CXXMethodDecl* RecordInfo::InheritsNonVirtualTrace() {
   if (CXXMethodDecl* trace = GetTraceMethod())
     return trace->isVirtual() ? 0 : trace;
   for (Bases::iterator it = GetBases().begin(); it != GetBases().end(); ++it) {
     if (CXXMethodDecl* trace = it->second.info()->InheritsNonVirtualTrace())
@@ skipping 26 matching lines @@
   if (!record_->hasDefinition())
     return bases;
   for (CXXRecordDecl::base_class_iterator it = record_->bases_begin();
        it != record_->bases_end();
        ++it) {
     const CXXBaseSpecifier& spec = *it;
     RecordInfo* info = cache_->Lookup(spec.getType());
     if (!info)
       continue;
     CXXRecordDecl* base = info->record();
-    TracingStatus status = info->InheritsNonPureTrace()
+    TracingStatus status = info->InheritsTrace()
                                ? TracingStatus::Needed()
                                : TracingStatus::Unneeded();
     bases->insert(std::make_pair(base, BasePoint(spec, info, status)));
   }
   return bases;
 }
 
 RecordInfo::Fields& RecordInfo::GetFields() {
   if (!fields_)
     fields_ = CollectFields();
@@ skipping 179 matching lines @@
         edge->members().push_back(member);
       }
       // TODO: Handle the case where we fail to create an edge (eg, if the
       // argument is a primitive type or just not fully known yet).
     }
     return edge;
   }
 
   return new Value(info);
 }