Allow arbitrary names for weak references in heap snapshots.

src/heap-snapshot-generator.cc

Index: src/heap-snapshot-generator.cc
diff --git a/src/heap-snapshot-generator.cc b/src/heap-snapshot-generator.cc
index 35cfcb4f68592c138b30b24c836aa490da4a7c09..b998e83033d30de9623eac3ba6e222cfeeffc17d 100644
--- a/src/heap-snapshot-generator.cc
+++ b/src/heap-snapshot-generator.cc
@@ -1114,11 +1114,9 @@ void V8HeapExplorer::ExtractJSObjectReferences(
     SetInternalReference(js_fun, entry,
                          "context", js_fun->context(),
                          JSFunction::kContextOffset);
-    for (int i = JSFunction::kNonWeakFieldsEndOffset;
-         i < JSFunction::kSize;
-         i += kPointerSize) {
-      SetWeakReference(js_fun, entry, i, *HeapObject::RawField(js_fun, i), i);

[yurys, 2014/01/24 14:02:55]

Please add STATIC_CHECK that there are no other weak fields.

-    }
+    SetWeakReference(js_fun, entry,
+                     "next_function_link", js_fun->next_function_link(),
+                     JSFunction::kNextFunctionLinkOffset);
   } else if (obj->IsGlobalObject()) {
     GlobalObject* global_obj = GlobalObject::cast(obj);
     SetInternalReference(global_obj, entry,
@@ -1180,8 +1178,13 @@ void V8HeapExplorer::ExtractContextReferences(int entry, Context* context) {
   }
 
 #define EXTRACT_CONTEXT_FIELD(index, type, name) \
-  SetInternalReference(context, entry, #name, context->get(Context::index), \
-      FixedArray::OffsetOfElementAt(Context::index));
+  if (Context::index < Context::FIRST_WEAK_SLOT) { \
+    SetInternalReference(context, entry, #name, context->get(Context::index), \
+        FixedArray::OffsetOfElementAt(Context::index)); \
+  } else { \
+    SetWeakReference(context, entry, #name, context->get(Context::index), \
+        FixedArray::OffsetOfElementAt(Context::index)); \
+  }
   EXTRACT_CONTEXT_FIELD(CLOSURE_INDEX, JSFunction, closure);
   EXTRACT_CONTEXT_FIELD(PREVIOUS_INDEX, Context, previous);
   EXTRACT_CONTEXT_FIELD(EXTENSION_INDEX, Object, extension);
@@ -1193,13 +1196,14 @@ void V8HeapExplorer::ExtractContextReferences(int entry, Context* context) {
     TagObject(context->runtime_context(), "(runtime context)");
     TagObject(context->embedder_data(), "(context data)");
     NATIVE_CONTEXT_FIELDS(EXTRACT_CONTEXT_FIELD);
+    EXTRACT_CONTEXT_FIELD(OPTIMIZED_FUNCTIONS_LIST, , optimized_functions_list);
+    EXTRACT_CONTEXT_FIELD(OPTIMIZED_CODE_LIST, , optimized_code_list);
+    EXTRACT_CONTEXT_FIELD(DEOPTIMIZED_CODE_LIST, , deoptimized_code_list);
+    EXTRACT_CONTEXT_FIELD(NEXT_CONTEXT_LINK, , next_context_link);
 #undef EXTRACT_CONTEXT_FIELD
-    for (int i = Context::FIRST_WEAK_SLOT;
-         i < Context::NATIVE_CONTEXT_SLOTS;
-         ++i) {
-      SetWeakReference(context, entry, i, context->get(i),
-          FixedArray::OffsetOfElementAt(i));
-    }
+    STATIC_CHECK(Context::OPTIMIZED_FUNCTIONS_LIST == Context::FIRST_WEAK_SLOT);
+    STATIC_CHECK(Context::NEXT_CONTEXT_LINK + 1
+                 == Context::NATIVE_CONTEXT_SLOTS);
   }
 }
 
@@ -1293,7 +1297,7 @@ void V8HeapExplorer::ExtractSharedFunctionInfoReferences(
                        "optimized_code_map", shared->optimized_code_map(),
                        SharedFunctionInfo::kOptimizedCodeMapOffset);
   SetWeakReference(obj, entry,
-                   1, shared->initial_map(),
+                   "initial_map", shared->initial_map(),
                    SharedFunctionInfo::kInitialMapOffset);
 }
 
@@ -1823,17 +1827,17 @@ void V8HeapExplorer::SetHiddenReference(HeapObject* parent_obj,
 
 void V8HeapExplorer::SetWeakReference(HeapObject* parent_obj,
                                       int parent_entry,
-                                      int index,
+                                      const char* reference_name,
                                       Object* child_obj,
                                       int field_offset) {
   ASSERT(parent_entry == GetEntry(parent_obj)->index());
   HeapEntry* child_entry = GetEntry(child_obj);
   if (child_entry == NULL) return;
   if (IsEssentialObject(child_obj)) {
-    filler_->SetIndexedReference(HeapGraphEdge::kWeak,
-                                 parent_entry,
-                                 index,
-                                 child_entry);
+    filler_->SetNamedReference(HeapGraphEdge::kWeak,
+                               parent_entry,
+                               reference_name,
+                               child_entry);
   }
   IndexedReferencesExtractor::MarkVisitedField(parent_obj, field_offset);
 }