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ggaren@apple.com authored
https://bugs.webkit.org/show_bug.cgi?id=39200 Reviewed by Darin Adler. Removed the reserved OptionalCalleeArguments slot from the CallFrame. Now, slots for 'arguments' are allocated and initialized only by functions that might need them. * bytecode/CodeBlock.cpp: (JSC::CodeBlock::dump): Updated for new bytecode operands. (JSC::CodeBlock::CodeBlock): * bytecode/CodeBlock.h: (JSC::unmodifiedArgumentsRegister): Added a helper function for mapping from the arguments register to its unmodified counterpart. (JSC::CodeBlock::setArgumentsRegister): (JSC::CodeBlock::argumentsRegister): (JSC::CodeBlock::usesArguments): Changed from a "usesArguments" bool to an optional int index representing the arguments register. * bytecode/Opcode.h: Updated for new bytecode operands. * bytecompiler/BytecodeGenerator.cpp: (JSC::BytecodeGenerator::addVar): Factored out a helper function for allocating an anonymous var. (JSC::BytecodeGenerator::BytecodeGenerator): Merged / simplified some arguments vs activation logic, and added code to allocate the arguments registers when needed. (JSC::BytecodeGenerator::createArgumentsIfNecessary): Updated for new bytecode operands. (JSC::BytecodeGenerator::emitCallEval): No need to create the arguments object before calling eval; the activation object will lazily create the arguments object if eval resolves it. (JSC::BytecodeGenerator::emitReturn): Updated for new bytecode operands. (JSC::BytecodeGenerator::emitPushScope): (JSC::BytecodeGenerator::emitPushNewScope): Ditto emitCallEval. * bytecompiler/BytecodeGenerator.h: (JSC::BytecodeGenerator::addVar): Factored out a helper function for allocating an anonymous var. (JSC::BytecodeGenerator::registerFor): No more need for special handling of the arguments registers; they're allocated just like normal registers now. * interpreter/CallFrame.h: (JSC::ExecState::callerFrame): (JSC::ExecState::init): * interpreter/CallFrameClosure.h: (JSC::CallFrameClosure::resetCallFrame): Nixed optionalCalleeArguments. * interpreter/Interpreter.cpp: (JSC::Interpreter::dumpRegisters): (JSC::Interpreter::unwindCallFrame): (JSC::Interpreter::privateExecute): (JSC::Interpreter::retrieveArguments): Opcodes accessing 'arguments' now take operands specifying registers, just like all other opcodes. JSActivation::copyRegisters is no longer responsible for tearing off the arguments object; instead, the VM is responsible for both. Also, a behavior change: Each access to f.arguments creates a new object, unless f itself uses 'arguments'. This matches Chrome, and is necessary for the optimization. f.arguments is a nonstandard, deprecated feature, so high fidelity to a given implementation is not necessarily a goal. Also, as illustrated by the new test case, the identity of f.arguments has been broken since 2008, except in the case where f itself accesses f.arguments -- but nobody seemed to notice. So, hopefully this change won't break the web. * interpreter/Register.h: Nixed the special arguments accessor. It's no longer needed. * interpreter/RegisterFile.h: (JSC::RegisterFile::): * jit/JITCall.cpp: (JSC::JIT::compileOpCallInitializeCallFrame): (JSC::JIT::compileOpCall): * jit/JITOpcodes.cpp: (JSC::JIT::emit_op_tear_off_activation): (JSC::JIT::emit_op_tear_off_arguments): (JSC::JIT::emit_op_create_arguments): (JSC::JIT::emit_op_init_arguments): * jit/JITOpcodes32_64.cpp: (JSC::JIT::emit_op_tear_off_activation): (JSC::JIT::emit_op_tear_off_arguments): (JSC::JIT::emit_op_create_arguments): (JSC::JIT::emit_op_init_arguments): The actual optimization: Removed OptionalCalleeArguments from the callframe slot. Now, it doesn't need to be initialized for most calls. * jit/JITStubs.cpp: (JSC::DEFINE_STUB_FUNCTION): * jit/JITStubs.h: (JSC::): Updated stubs to support arbitrary 'arguments' registers, instead of hard-coding something in the call frame. * runtime/Arguments.h: (JSC::JSActivation::copyRegisters): Removed some obfuscatory abstraction. * runtime/Executable.h: (JSC::FunctionExecutable::generatedByteCode): Added a helper for accessing the 'arguments' register. In a future patch, that kind of data should probably move out of CodeBlock and into Executable. * runtime/JSActivation.cpp: (JSC::JSActivation::getOwnPropertySlot): (JSC::JSActivation::argumentsGetter): * runtime/JSActivation.h: Simplified / fixed access to 'arguments' via the activation object. It now implements the same behavior implemented by optimized variable access in the VM. This simplifies some other things, too -- like eval code generation. LayoutTests: Simplified handling of 'arguments' -- 1.2% SunSpider speedup https://bugs.webkit.org/show_bug.cgi?id=39200 Reviewed by Darin Adler. * fast/js/function-dot-arguments-expected.txt: * fast/js/script-tests/function-dot-arguments.js: (argumentsIdentity): Updated to match new behavior. * fast/js/function-dot-arguments2-expected.txt: * fast/js/function-dot-arguments2.html: New tests for some things that weren't covered before. * fast/js/global-recursion-on-full-stack.html: Rejiggered the stack usage in this test. Since stack usage is more efficient now, you need a slightly different usage pattern to hit the exact thing this test wanted to test. * fast/js/kde/script-tests/function_arguments.js: (f): Updated to more specifically test what this was trying to test, to avoid just testing the identity of f.arguments. git-svn-id: http://svn.webkit.org/repository/webkit/trunk@59742 268f45cc-cd09-0410-ab3c-d52691b4dbfc
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