GC plugin: improve error reporting when tracing illegal fields.

tools/clang/blink_gc_plugin/RecordInfo.cpp

Index: tools/clang/blink_gc_plugin/RecordInfo.cpp
diff --git a/tools/clang/blink_gc_plugin/RecordInfo.cpp b/tools/clang/blink_gc_plugin/RecordInfo.cpp
index f0e2ade715bb63255b5d0e34eaf54097de1c28b7..0b37e35393b037efbacfb8ba97694ab5a4d3497f 100644
--- a/tools/clang/blink_gc_plugin/RecordInfo.cpp
+++ b/tools/clang/blink_gc_plugin/RecordInfo.cpp
@@ -599,6 +599,19 @@ Edge* RecordInfo::CreateEdge(const Type* type) {
     return 0;
   }
 
+  if (Config::IsUniquePtr(info->name()) && info->GetTemplateArgs(1, &args)) {
+    // Check that this is std::unique_ptr
+    NamespaceDecl* ns =
+        dyn_cast<NamespaceDecl>(info->record()->getDeclContext());
+    if (!ns || ns->getName() != "std")

[Nico, 2016/06/14 11:35:15]

(this isn't new in this patch, but in general i think it's nicer to look up
global ::std and then compare the decl, instead of doing this with string
matching. in this case, I think Sema has a public getStdNamespace() method; also
in that other class that compares against "unique_ptr" etc)

[sof, 2016/06/14 21:01:22]

Thanks for the Sema tip, adjusted to use instead.

+      return 0;
+    if (!info->GetTemplateArgs(1, &args))
+      return 0;
+    if (Edge* ptr = CreateEdge(args[0]))
+      return new UniquePtr(ptr);
+    return 0;
+  }
+
   if (Config::IsMember(info->name()) && info->GetTemplateArgs(1, &args)) {
     if (Edge* ptr = CreateEdge(args[0]))
       return new Member(ptr);
@@ -611,7 +624,8 @@ Edge* RecordInfo::CreateEdge(const Type* type) {
     return 0;
   }
 
-  if (Config::IsPersistent(info->name())) {
+  bool is_persistent = Config::IsPersistent(info->name());
+  if (is_persistent || Config::IsCrossThreadPersistent(info->name())) {
     // Persistent might refer to v8::Persistent, so check the name space.
     // TODO: Consider using a more canonical identification than names.
     NamespaceDecl* ns =
@@ -620,8 +634,12 @@ Edge* RecordInfo::CreateEdge(const Type* type) {
       return 0;
     if (!info->GetTemplateArgs(1, &args))
       return 0;
-    if (Edge* ptr = CreateEdge(args[0]))
-      return new Persistent(ptr);
+    if (Edge* ptr = CreateEdge(args[0])) {
+      if (is_persistent)
+        return new Persistent(ptr);
+      else
+        return new CrossThreadPersistent(ptr);
+    }
     return 0;
   }