[heap-stats] Log on- and off-heap script sources

Special case script logging to also log the source of the script, even
if that source is off-heap in an external string.

Bug: v8:7266
Change-Id: I0d35f94f7b27d0d793d1a1a3fb8d3280960b253d
Reviewed-on: https://chromium-review.googlesource.com/899344
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51076}

src/heap/object-stats.cc

@@ -650,6 +650,27 @@ void ObjectStatsCollectorImpl::RecordVirtualScriptDetails(Script* script) {
           ObjectStats::SCRIPT_SHARED_FUNCTION_INFOS_TYPE);
     }
   }
+
+  // Log the size of external source code.
+  Object* source = script->source();
+  if (source->IsExternalString()) {
+    // The contents of external strings aren't on the heap, so we have to record
+    // them manually.
+    ExternalString* external_source_string = ExternalString::cast(source);
+    size_t length_multiplier = external_source_string->IsTwoByteRepresentation()
+                                   ? kShortSize
+                                   : kCharSize;
+    size_t off_heap_size = external_source_string->length() * length_multiplier;
+    size_t on_heap_size = external_source_string->Size();
+    RecordVirtualObjectStats(script, external_source_string,
+                             ObjectStats::SCRIPT_SOURCE_EXTERNAL_TYPE,
+                             on_heap_size + off_heap_size,
+                             ObjectStats::kNoOverAllocation);
+  } else if (source->IsHeapObject()) {
+    RecordSimpleVirtualObjectStats(
+        script, HeapObject::cast(source),
+        ObjectStats::SCRIPT_SOURCE_NON_EXTERNAL_TYPE);
+  }
 }
 
 void ObjectStatsCollectorImpl::RecordVirtualSharedFunctionInfoDetails(

src/heap/object-stats.h

@@ -60,6 +60,8 @@
   V(SCOPE_INFO_TYPE)                        \
   V(SCRIPT_LIST_TYPE)                       \
   V(SCRIPT_SHARED_FUNCTION_INFOS_TYPE)      \
+  V(SCRIPT_SOURCE_EXTERNAL_TYPE)            \
+  V(SCRIPT_SOURCE_NON_EXTERNAL_TYPE)        \
   V(SERIALIZED_OBJECTS_TYPE)                \
   V(SINGLE_CHARACTER_STRING_CACHE_TYPE)     \
   V(STRING_SPLIT_CACHE_TYPE)                \

tools/heap-stats/categories.js

@@ -158,6 +158,8 @@ const CATEGORIES = new Map([
       'LOAD_HANDLER_TYPE',
       'NOSCRIPT_SHARED_FUNCTION_INFOS_TYPE',
       'OPTIMIZED_CODE_LITERALS_TYPE',
+      'SCRIPT_SOURCE_EXTERNAL_TYPE',
+      'SCRIPT_SOURCE_NON_EXTERNAL_TYPE',
       'SCRIPT_TYPE',
       'SHARED_FUNCTION_INFO_TYPE',
       'STORE_HANDLER_TYPE',