blink_gc_plugin: detect singletons with embedded ScriptWrappables.

tools/clang/blink_gc_plugin/BlinkGCPluginConsumer.cpp

 // Copyright 2015 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 "BlinkGCPluginConsumer.h"
 
 #include <algorithm>
 #include <set>
 
 #include "CheckDispatchVisitor.h"
 #include "CheckFieldsVisitor.h"
 #include "CheckFinalizerVisitor.h"
 #include "CheckGCRootsVisitor.h"
+#include "CheckSingletonVisitor.h"
 #include "CheckTraceVisitor.h"
 #include "CollectVisitor.h"
 #include "JsonWriter.h"
 #include "RecordInfo.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Sema/Sema.h"
 
 using namespace clang;
 
 namespace {
@@ skipping 56 matching lines @@
     Config::UseLegacyNames();
 }
 
 void BlinkGCPluginConsumer::HandleTranslationUnit(ASTContext& context) {
   // Don't run the plugin if the compilation unit is already invalid.
   if (reporter_.hasErrorOccurred())
     return;
 
   ParseFunctionTemplates(context.getTranslationUnitDecl());
 
-  CollectVisitor visitor;
+  CollectVisitor visitor(options_.warn_singleton_with_scriptwrappables);
   visitor.TraverseDecl(context.getTranslationUnitDecl());
 
   if (options_.dump_graph) {
     std::error_code err;
     // TODO: Make createDefaultOutputFile or a shorter createOutputFile work.
     json_ = JsonWriter::from(instance_.createOutputFile(
         "",                                      // OutputPath
         err,                                     // Errors
         true,                                    // Binary
         true,                                    // RemoveFileOnSignal
@@ skipping 12 matching lines @@
           << "Failed to create an output file for the object graph.\n";
     }
   }
 
   for (const auto& record : visitor.record_decls())
     CheckRecord(cache_.Lookup(record));
 
   for (const auto& method : visitor.trace_decls())
     CheckTracingMethod(method);
 
+  for (const auto& singleton : visitor.singleton_decls())
+    CheckStaticSingleton(singleton);
+
   if (json_) {
     json_->CloseList();
     delete json_;
     json_ = 0;
   }
 }
 
 void BlinkGCPluginConsumer::ParseFunctionTemplates(TranslationUnitDecl* decl) {
   if (!instance_.getLangOpts().DelayedTemplateParsing)
     return;  // Nothing to do.
@@ skipping 424 matching lines @@
   for (auto& field : parent->GetFields()) {
     if (!field.second.IsProperlyTraced() ||
         field.second.IsInproperlyTraced()) {
       // Report one or more tracing-related field errors.
       reporter_.FieldsImproperlyTraced(parent, trace);
       break;
     }
   }
 }
 
+void BlinkGCPluginConsumer::CheckStaticSingleton(clang::VarDecl* singleton) {
+  // Ignorance is a declaration-level annotation, so eagerly checked for
+  // before adding it to the processing set.
+  assert(!Config::IsIgnoreAnnotated(singleton));
+
+  const Type* singleton_type = singleton->getType().getTypePtr();
+  if (singleton_type->isPointerType() || singleton_type->isReferenceType())
+    singleton_type = singleton_type->getPointeeType().getTypePtr();
+
+  CXXRecordDecl* record = singleton_type->getAsCXXRecordDecl();
+  if (!record)
+    return;
+
+  RecordInfo* info = cache_.Lookup(record);
+  if (!info)
+    return;
+
+  // Walk over singleton type, looking for undesirable ScriptWrappable
+  // references.
+  CheckSingletonVisitor visitor;
+  if (!visitor.CheckIfSafe(info, singleton_type)) {
+    reporter_.StaticSingletonContainsScriptWrappable(singleton);
+    for (auto error : visitor.illegal_types()) {

[dcheng, 2017/02/16 04:35:51]

const auto& to suppress a copy

[sof, 2017/02/16 06:45:34]

done, thanks for catching that one.

+      reporter_.NoteUnsafeScriptWrappableField(
+          singleton, error.first,
+          QualType::getAsString(
+              error.second->getCanonicalTypeInternal().split()));
+    }
+  }
+}
+
 void BlinkGCPluginConsumer::DumpClass(RecordInfo* info) {
   if (!json_)
     return;
 
   json_->OpenObject();
   json_->Write("name", info->record()->getQualifiedNameAsString());
   json_->Write("loc", GetLocString(info->record()->getLocStart()));
   json_->CloseObject();
 
   class DumpEdgeVisitor : public RecursiveEdgeVisitor {
@@ skipping 140 matching lines @@
   SourceLocation spelling_location = source_manager.getSpellingLoc(loc);
   PresumedLoc ploc = source_manager.getPresumedLoc(spelling_location);
   if (ploc.isInvalid()) {
     // If we're in an invalid location, we're looking at things that aren't
     // actually stated in the source.
     return false;
   }
   *filename = ploc.getFilename();
   return true;
 }