Fixed an ordering issue found by UBSan_vptr.

We managed to access the scope_ member of CompilationInfo before its
containing object was actually constructed.

Rule of thumb: When constructing an object, never ever pass around
pointers to members which come later in the member initializer list,
you simply can't see locally if this might cause trouble or not.

Review URL: https://codereview.chromium.org/796363002

Cr-Commit-Position: refs/heads/master@{#25796}

src/code-stubs-hydrogen.cc

@@ -34,11 +34,11 @@ static LChunk* OptimizeGraph(HGraph* graph) {
 
 class CodeStubGraphBuilderBase : public HGraphBuilder {
  public:
-  CodeStubGraphBuilderBase(Isolate* isolate, HydrogenCodeStub* stub)
-      : HGraphBuilder(&info_),
+  explicit CodeStubGraphBuilderBase(CompilationInfoWithZone* info)
+      : HGraphBuilder(info),
         arguments_length_(NULL),
-        info_(stub, isolate),
-        descriptor_(stub),
+        info_(info),
+        descriptor_(info->code_stub()),
         context_(NULL) {
     int parameter_count = descriptor_.GetEnvironmentParameterCount();
     parameters_.Reset(new HParameter*[parameter_count]);
@@ -56,10 +56,10 @@ class CodeStubGraphBuilderBase : public HGraphBuilder {
     DCHECK(arguments_length_ != NULL);
     return arguments_length_;
   }
-  CompilationInfo* info() { return &info_; }
-  HydrogenCodeStub* stub() { return info_.code_stub(); }
+  CompilationInfo* info() { return info_; }
+  HydrogenCodeStub* stub() { return info_->code_stub(); }
   HContext* context() { return context_; }
-  Isolate* isolate() { return info_.isolate(); }
+  Isolate* isolate() { return info_->isolate(); }
 
   HLoadNamedField* BuildLoadNamedField(HValue* object,
                                        FieldIndex index);
@@ -106,7 +106,7 @@ class CodeStubGraphBuilderBase : public HGraphBuilder {
 
   SmartArrayPointer<HParameter*> parameters_;
   HValue* arguments_length_;
-  CompilationInfoWithZone info_;
+  CompilationInfoWithZone* info_;
   CodeStubDescriptor descriptor_;
   HContext* context_;
 };
@@ -120,7 +120,7 @@ bool CodeStubGraphBuilderBase::BuildGraph() {
     const char* name = CodeStub::MajorName(stub()->MajorKey(), false);
     PrintF("-----------------------------------------------------------\n");
     PrintF("Compiling stub %s using hydrogen\n", name);
-    isolate()->GetHTracer()->TraceCompilation(&info_);
+    isolate()->GetHTracer()->TraceCompilation(info());
   }
 
   int param_count = descriptor_.GetEnvironmentParameterCount();
@@ -189,8 +189,8 @@ bool CodeStubGraphBuilderBase::BuildGraph() {
 template <class Stub>
 class CodeStubGraphBuilder: public CodeStubGraphBuilderBase {
  public:
-  CodeStubGraphBuilder(Isolate* isolate, Stub* stub)
-      : CodeStubGraphBuilderBase(isolate, stub) {}
+  explicit CodeStubGraphBuilder(CompilationInfoWithZone* info)
+      : CodeStubGraphBuilderBase(info) {}
 
  protected:
   virtual HValue* BuildCodeStub() {
@@ -271,7 +271,8 @@ static Handle<Code> DoGenerateCode(Stub* stub) {
   if (FLAG_profile_hydrogen_code_stub_compilation) {
     timer.Start();
   }
-  CodeStubGraphBuilder<Stub> builder(isolate, stub);
+  CompilationInfoWithZone info(stub, isolate);
+  CodeStubGraphBuilder<Stub> builder(&info);
   LChunk* chunk = OptimizeGraph(builder.CreateGraph());
   Handle<Code> code = chunk->Codegen();
   if (FLAG_profile_hydrogen_code_stub_compilation) {
@@ -1700,8 +1701,8 @@ template <>
 class CodeStubGraphBuilder<KeyedLoadGenericStub>
     : public CodeStubGraphBuilderBase {
  public:
-  CodeStubGraphBuilder(Isolate* isolate, KeyedLoadGenericStub* stub)
-      : CodeStubGraphBuilderBase(isolate, stub) {}
+  explicit CodeStubGraphBuilder(CompilationInfoWithZone* info)
+      : CodeStubGraphBuilderBase(info) {}
 
  protected:
   virtual HValue* BuildCodeStub();