GCPlugin: Recognize templated registerWeakMembers() call.

tools/clang/blink_gc_plugin/BlinkGCPlugin.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.
 
 // This clang plugin checks various invariants of the Blink garbage
 // collection infrastructure.
 //
 // Errors are described at:
 // http://www.chromium.org/developers/blink-gc-plugin-errors
 
@@ skipping 370 matching lines @@
     if (call->getNumArgs() != 1)
       return true;
     Expr* arg = call->getArg(0);
 
     if (UnresolvedMemberExpr* expr = dyn_cast<UnresolvedMemberExpr>(callee)) {
       // This could be a trace call of a base class, as explained in the
       // comments of CheckTraceBaseCall().
       if (CheckTraceBaseCall(call))
         return true;
 
-      // If we find a call to registerWeakMembers which is unresolved we
-      // unsoundly consider all weak members as traced.
-      // TODO: Find out how to validate weak member tracing for unresolved call.
-      if (expr->getMemberName().getAsString() == kRegisterWeakMembersName) {
-        for (RecordInfo::Fields::iterator it = info_->GetFields().begin();
-             it != info_->GetFields().end();
-             ++it) {
-          if (it->second.edge()->IsWeakMember())
-            it->second.MarkTraced();
-        }
-      }
+      if (expr->getMemberName().getAsString() == kRegisterWeakMembersName)
+        MarkAllWeakMembersTraced();
 
       QualType base = expr->getBaseType();
       if (!base->isPointerType())
         return true;
       CXXRecordDecl* decl = base->getPointeeType()->getAsCXXRecordDecl();
       if (decl)
         CheckTraceFieldCall(expr->getMemberName().getAsString(), decl, arg);
       if (Config::IsTraceImplName(expr->getMemberName().getAsString()))
         delegates_to_traceimpl_ = true;
       return true;
@@ skipping 35 matching lines @@
     if (!type)
       return 0;
 
     return RecordInfo::GetDependentTemplatedDecl(*type);
   }
 
   void CheckCXXDependentScopeMemberExpr(CallExpr* call,
                                         CXXDependentScopeMemberExpr* expr) {
     string fn_name = expr->getMember().getAsString();
 
-    // Check for VisitorDispatcher::trace(field)
+    // Check for VisitorDispatcher::trace(field) and
+    // VisitorDispatcher::registerWeakMembers.
     if (!expr->isImplicitAccess()) {
       if (clang::DeclRefExpr* base_decl =
               clang::dyn_cast<clang::DeclRefExpr>(expr->getBase())) {
-        if (Config::IsVisitorDispatcherType(base_decl->getType()) &&
-            call->getNumArgs() == 1 && fn_name == kTraceName) {
-          FindFieldVisitor finder;
-          finder.TraverseStmt(call->getArg(0));
-          if (finder.field())
-            FoundField(finder.field());
+        if (Config::IsVisitorDispatcherType(base_decl->getType())) {
+          if (call->getNumArgs() == 1 && fn_name == kTraceName) {
+            FindFieldVisitor finder;
+            finder.TraverseStmt(call->getArg(0));
+            if (finder.field())
+              FoundField(finder.field());
 
-          return;
+            return;
+          } else if (call->getNumArgs() == 1 &&
+                     fn_name == kRegisterWeakMembersName) {
+            MarkAllWeakMembersTraced();
+          }
         }
       }
     }
 
     CXXRecordDecl* tmpl = GetDependentTemplatedDecl(expr);
     if (!tmpl)
       return;
 
     // Check for Super<T>::trace(visitor)
     if (call->getNumArgs() == 1 && IsTraceCallName(fn_name)) {
@@ skipping 210 matching lines @@
           break;
         }
       }
     } else {
       RecordInfo::Fields::iterator it = info_->GetFields().find(field);
       if (it != info_->GetFields().end())
         MarkTraced(it);
     }
   }
 
+  void MarkAllWeakMembersTraced() {
+    // If we find a call to registerWeakMembers which is unresolved we
+    // unsoundly consider all weak members as traced.
+    // TODO: Find out how to validate weak member tracing for unresolved call.
+    for (auto& field : info_->GetFields()) {
+      if (field.second.edge()->IsWeakMember())
+        field.second.MarkTraced();
+    }
+  }
+
   CXXMethodDecl* trace_;
   RecordInfo* info_;
   RecordCache* cache_;
   bool delegates_to_traceimpl_;
 };
 
 // This visitor checks that the fields of a class and the fields of
 // its part objects don't define GC roots.
 class CheckGCRootsVisitor : public RecursiveEdgeVisitor {
  public:
@@ skipping 1338 matching lines @@
 
  private:
   BlinkGCPluginOptions options_;
 };
 
 }  // namespace
 
 static FrontendPluginRegistry::Add<BlinkGCPluginAction> X(
     "blink-gc-plugin",
     "Check Blink GC invariants");