-
ggaren@apple.com authored
https://bugs.webkit.org/show_bug.cgi?id=95591 Reviewed by Sam Weinig. Removed the global object, global data, and global this pointers from JSScope, and changed an int to a bitfield. This gets the JSActivation class down to 64 bytes, which in practice cuts it in half by getting it out of the 128 byte size class. Now, it's one extra indirection to get these pointers. These pointers aren't accessed by JIT code, so I thought there would be no cost to the extra indirection. However, some C++-heavy SunSpider tests regressed a bit in an early version of the patch, which added even more indirection. This suggests that calls to exec->globalData() and/or exec->lexicalGlobalObject() are common and probably duplicated in lots of places, and could stand further optimization in C++. * dfg/DFGAbstractState.cpp: (JSC::DFG::AbstractState::execute): Test against the specific activation for our global object, since there's no VM-shared activation structure anymore. This is guaranteed to have the same success rate as the old test because activation scope is fixed at compile time. * heap/MarkedBlock.cpp: (JSC::MarkedBlock::MarkedBlock): * heap/MarkedBlock.h: (JSC::MarkedBlock::globalData): * heap/WeakSet.cpp: (JSC::WeakSet::addAllocator): * heap/WeakSet.h: (WeakSet): (JSC::WeakSet::WeakSet): (JSC::WeakSet::globalData): Store a JSGlobalData* instead of a Heap* because JSGlobalData->Heap is just a constant fold in the addressing mode, while Heap->JSGlobalData is an extra pointer dereference. (These objects should eventually just merge.) * jit/JITOpcodes.cpp: (JSC::JIT::emit_op_resolve_global_dynamic): See DFGAbstractState.cpp. * llint/LowLevelInterpreter32_64.asm: * llint/LowLevelInterpreter64.asm: Load the activation structure from the code block instead of the global data because the structure is not VM-shared anymore. (See DFGAbstractState.cpp.) * runtime/JSActivation.cpp: (JSC::JSActivation::JSActivation): * runtime/JSActivation.h: (JSActivation): This is the point of the patch: Remove the data. * runtime/JSGlobalData.cpp: (JSC::JSGlobalData::JSGlobalData): * runtime/JSGlobalData.h: (JSGlobalData): No longer VM-shared. (See DFGAbstractState.cpp.) (JSC::WeakSet::heap): (See WeakSet.h.) * runtime/JSGlobalObject.cpp: (JSC::JSGlobalObject::JSGlobalObject): (JSC::JSGlobalObject::setGlobalThis): (JSC::JSGlobalObject::reset): (JSC::JSGlobalObject::visitChildren): * runtime/JSGlobalObject.h: (JSGlobalObject): (JSC::JSGlobalObject::withScopeStructure): (JSC::JSGlobalObject::strictEvalActivationStructure): (JSC::JSGlobalObject::activationStructure): (JSC::JSGlobalObject::nameScopeStructure): (JSC::JSScope::globalThis): (JSC::JSGlobalObject::globalThis): Data that used to be in the JSScope class goes here now, so it's not duplicated across all activations. * runtime/JSNameScope.h: (JSC::JSNameScope::JSNameScope): * runtime/JSScope.cpp: (JSC::JSScope::visitChildren): This is the point of the patch: Remove the data. * runtime/JSScope.h: (JSScope): (JSC::JSScope::JSScope): (JSC::JSScope::globalObject): (JSC::JSScope::globalData): * runtime/JSSegmentedVariableObject.h: (JSC::JSSegmentedVariableObject::JSSegmentedVariableObject): * runtime/JSSymbolTableObject.h: (JSC::JSSymbolTableObject::JSSymbolTableObject): * runtime/JSVariableObject.h: (JSC::JSVariableObject::JSVariableObject): * runtime/JSWithScope.h: (JSC::JSWithScope::JSWithScope): * runtime/StrictEvalActivation.cpp: (JSC::StrictEvalActivation::StrictEvalActivation): Simplified now that we don't need to pass so much data to JSScope. git-svn-id: http://svn.webkit.org/repository/webkit/trunk@127293 268f45cc-cd09-0410-ab3c-d52691b4dbfc
0b44fca6