blink_gc_plugin: detect singletons with embedded ScriptWrappables.

tools/clang/blink_gc_plugin/DiagnosticsReporter.cpp

Index: tools/clang/blink_gc_plugin/DiagnosticsReporter.cpp
diff --git a/tools/clang/blink_gc_plugin/DiagnosticsReporter.cpp b/tools/clang/blink_gc_plugin/DiagnosticsReporter.cpp
index 95d5595beb5f38ffe8f690c98a710a3dee062971..fc28fc453566d30eeca66a20c15f59e9af5da338 100644
--- a/tools/clang/blink_gc_plugin/DiagnosticsReporter.cpp
+++ b/tools/clang/blink_gc_plugin/DiagnosticsReporter.cpp
@@ -147,13 +147,21 @@ const char kBaseClassMustDeclareVirtualTrace[] =
     "[blink-gc] Left-most base class %0 of derived class %1"
     " must define a virtual trace method.";
 
-const char kIteratorToGCManagedCollectionNote[] =
+const char kIteratorToGCManagedCollection[] =
     "[blink-gc] Iterator field %0 to a GC managed collection declared here:";
 
-const char kTraceMethodOfStackAllocatedParentNote[] =
+const char kTraceMethodOfStackAllocatedParent[] =
     "[blink-gc] The stack allocated class %0 provides an unnecessary "
     "trace method:";
 
+const char kStaticSingletonContainsScriptWrappable[] =
+    "[blink-gc] The static singleton %0 contains one or more unsafe "
+    "ScriptWrappable references";
+
+const char kUnsafeScriptWrappableFieldNote[] =
+    "[blink-gc] Embedded unsafe ScriptWrappable-derived field with type '%1' "
+    "located at '%0'";
+
 } // namespace
 
 DiagnosticBuilder DiagnosticsReporter::ReportDiagnostic(
@@ -164,6 +172,10 @@ DiagnosticBuilder DiagnosticsReporter::ReportDiagnostic(
   return diagnostic_.Report(full_loc, diag_id);
 }
 
+DiagnosticBuilder DiagnosticsReporter::ReportDiagnostic(unsigned diag_id) {
+  return diagnostic_.Report(diag_id);
+}
+
 DiagnosticsReporter::DiagnosticsReporter(
     clang::CompilerInstance& instance)
     : instance_(instance),
@@ -214,10 +226,12 @@ DiagnosticsReporter::DiagnosticsReporter(
       getErrorLevel(), kLeftMostBaseMustBePolymorphic);
   diag_base_class_must_declare_virtual_trace_ = diagnostic_.getCustomDiagID(
       getErrorLevel(), kBaseClassMustDeclareVirtualTrace);
-  diag_iterator_to_gc_managed_collection_note_ = diagnostic_.getCustomDiagID(
-      getErrorLevel(), kIteratorToGCManagedCollectionNote);
+  diag_iterator_to_gc_managed_collection_ = diagnostic_.getCustomDiagID(
+      getErrorLevel(), kIteratorToGCManagedCollection);
   diag_trace_method_of_stack_allocated_parent_ = diagnostic_.getCustomDiagID(
-      getErrorLevel(), kTraceMethodOfStackAllocatedParentNote);
+      getErrorLevel(), kTraceMethodOfStackAllocatedParent);
+  diag_static_singleton_with_scriptwrappable_ = diagnostic_.getCustomDiagID(
+      getErrorLevel(), kStaticSingletonContainsScriptWrappable);
 
   // Register note messages.
   diag_base_requires_tracing_note_ = diagnostic_.getCustomDiagID(
@@ -264,6 +278,8 @@ DiagnosticsReporter::DiagnosticsReporter(
       DiagnosticsEngine::Note, kOverriddenNonVirtualTraceNote);
   diag_manual_dispatch_method_note_ = diagnostic_.getCustomDiagID(
       DiagnosticsEngine::Note, kManualDispatchMethodNote);
+  diag_unsafe_scriptwrappable_field_note_ = diagnostic_.getCustomDiagID(
+      DiagnosticsEngine::Note, kUnsafeScriptWrappableFieldNote);
 }
 
 bool DiagnosticsReporter::hasErrorOccurred() const
@@ -355,7 +371,7 @@ void DiagnosticsReporter::ClassContainsInvalidFields(
     } else if (error.second == CheckFieldsVisitor::kGCDerivedPartObject) {
       note = diag_part_object_to_gc_derived_class_note_;
     } else if (error.second == CheckFieldsVisitor::kIteratorToGCManaged) {
-      note = diag_iterator_to_gc_managed_collection_note_;
+      note = diag_iterator_to_gc_managed_collection_;
     } else {
       assert(false && "Unknown field error");
     }
@@ -513,6 +529,13 @@ void DiagnosticsReporter::TraceMethodForStackAllocatedClass(
       << info->record();
 }
 
+void DiagnosticsReporter::StaticSingletonContainsScriptWrappable(
+    VarDecl* decl) {
+  ReportDiagnostic(decl->getLocStart(),
+                   diag_static_singleton_with_scriptwrappable_)
+      << decl;
+}
+
 void DiagnosticsReporter::NoteManualDispatchMethod(CXXMethodDecl* dispatch) {
   ReportDiagnostic(dispatch->getLocStart(),
                    diag_manual_dispatch_method_note_)
@@ -580,3 +603,11 @@ void DiagnosticsReporter::NoteOverriddenNonVirtualTrace(
                    diag_overridden_non_virtual_trace_note_)
       << overridden;
 }
+
+void DiagnosticsReporter::NoteUnsafeScriptWrappableField(
+    VarDecl* decl,
+    const std::string& context,
+    const std::string& type_name) {
+  ReportDiagnostic(diag_unsafe_scriptwrappable_field_note_) << context
+                                                            << type_name;
+}