Changeset 197379 in webkit for trunk/Source/JavaScriptCore/runtime/JSObject.h

Timestamp:

Feb 29, 2016, 6:07:12 PM (9 years ago)

Author:

[email protected]

Message:

Add new MethodTable method to get an estimated size for a cell
​https://bugs.webkit.org/show_bug.cgi?id=154838

Patch by Joseph Pecoraro <Joseph Pecoraro> on 2016-02-29
Reviewed by Filip Pizlo.

The new class method estimatedSize(JSCell*) estimates the size for a single cell.
As the name implies, this is meant to be an approximation. It is more important
that big objects report a large size, then to get perfect size information for
all objects in the heap.

Base implementation (JSCell):

• returns the MarkedBlock bucket size for this cell.
• This gets us the object size include inline storage. Basically a better sizeof.

Subclasses with "Extra Memory Cost":

• Any class that reports extra memory (reportExtraMemoryVisited) should include that in the estimated size.
• E.g. CodeBlock, JSGenericTypedArrayView, WeakMapData, etc.

Subclasses with "Copied Space" storage:

• Any class with data in copied space (copyBackingStore) should include that in the estimated size.
• E.g. JSObject, JSGenericTypedArrayView, JSMap, JSSet, DirectArguments, etc.

Add reportExtraMemoryVisited for UnlinkedCodeBlock's compressed unlinked
instructions because this can be larger than 1kb, which is significant.

This has one special case for RegExp generated bytecode / JIT code, which
does not currently fall into the extra memory cost or copied space storage.
In practice I haven't seen this grow to a significant cost.

• runtime/ClassInfo.h:

Add the new estimatedSize method to the table.

• bytecode/UnlinkedCodeBlock.cpp:

(JSC::UnlinkedCodeBlock::visitChildren):
(JSC::UnlinkedCodeBlock::estimatedSize):
(JSC::UnlinkedCodeBlock::setInstructions):

• bytecode/UnlinkedCodeBlock.h:

Report an extra memory cost for unlinked code blocks like
we do for linked code blocks.

• bytecode/CodeBlock.cpp:

(JSC::CodeBlock::estimatedSize):

• bytecode/CodeBlock.h:
• bytecode/UnlinkedInstructionStream.cpp:

(JSC::UnlinkedInstructionStream::sizeInBytes):

• bytecode/UnlinkedInstructionStream.h:
• runtime/DirectArguments.cpp:

(JSC::DirectArguments::estimatedSize):

• runtime/DirectArguments.h:
• runtime/JSCell.cpp:

(JSC::JSCell::estimatedSizeInBytes):
(JSC::JSCell::estimatedSize):

• runtime/JSCell.h:
• runtime/JSGenericTypedArrayView.h:
• runtime/JSGenericTypedArrayViewInlines.h:

(JSC::JSGenericTypedArrayView<Adaptor>::estimatedSize):

• runtime/JSMap.cpp:

(JSC::JSMap::estimatedSize):

• runtime/JSMap.h:
• runtime/JSObject.cpp:

(JSC::JSObject::visitButterfly):

• runtime/JSObject.h:
• runtime/JSSet.cpp:

(JSC::JSSet::estimatedSize):

• runtime/JSSet.h:
• runtime/JSString.cpp:

(JSC::JSString::estimatedSize):

• runtime/JSString.h:
• runtime/MapData.h:

(JSC::MapDataImpl::capacityInBytes):

• runtime/WeakMapData.cpp:

(JSC::WeakMapData::estimatedSize):
(JSC::WeakMapData::visitChildren):

• runtime/WeakMapData.h:

Implement estimated size following the pattern of reporting
extra visited size, or copy space memory.

• runtime/RegExp.cpp:

(JSC::RegExp::estimatedSize):

• runtime/RegExp.h:
• yarr/YarrInterpreter.h:

(JSC::Yarr::ByteDisjunction::estimatedSizeInBytes):
(JSC::Yarr::BytecodePattern::estimatedSizeInBytes):

• yarr/YarrJIT.h:

(JSC::Yarr::YarrCodeBlock::size):
Include generated bytecode / JITCode to a RegExp's size.

File:

• trunk/Source/JavaScriptCore/runtime/JSObject.h (modified) (1 diff)

trunk/Source/JavaScriptCore/runtime/JSObject.h

@@ -95 +95 @@
 public:
     typedef JSCell Base;
-        
+
+    JS_EXPORT_PRIVATE static size_t estimatedSize(JSCell*);
     JS_EXPORT_PRIVATE static void visitChildren(JSCell*, SlotVisitor&);
     JS_EXPORT_PRIVATE static void copyBackingStore(JSCell*, CopyVisitor&, CopyToken);