Allocate local ScopeChain register
https://bugs.webkit.org/show_bug.cgi?id=138793
Reviewed by Geoffrey Garen.
Source/JavaScriptCore:
Now we allocate the scope register as a local. The allocated register is stored in the
CodeBlock for use by other components. Update the DFG to work with a local scope register.
Changed usage of JSStack::ScopeChain access to the CallFrame header to use the allocated
local register.
- bytecode/BytecodeUseDef.h:
(JSC::computeUsesForBytecodeOffset):
(JSC::computeDefsForBytecodeOffset):
Updated to properly represent the operand inputs and bytecode result.
(JSC::CodeBlock::CodeBlock):
(JSC::CodeBlock::setScopeRegister):
(JSC::CodeBlock::scopeRegister):
- bytecode/UnlinkedCodeBlock.h:
(JSC::UnlinkedCodeBlock::setScopeRegister):
(JSC::UnlinkedCodeBlock::scopeRegister):
Added scope register member and accessors.
- bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::allocateAndEmitScope):
- bytecompiler/BytecodeGenerator.h:
(JSC::BytecodeGenerator::scopeRegister):
Change m_scopeRegister to an allocated register. Added allocateAndEmitScope helper to
allocate the scope register, set the CodeBlock with its value and emit op_get_scope.
- debugger/DebuggerCallFrame.cpp:
(JSC::DebuggerCallFrame::scope): Changed to access the scope using the new convention.
- dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::get):
(JSC::DFG::ByteCodeParser::flush):
(JSC::DFG::ByteCodeParser::inlineCall):
(JSC::DFG::ByteCodeParser::parseBlock):
Changed op_create_lexical_environment to set the scope VirtualRegister operand.
Filled out op_get_scope processing to emit a GetScope node putting the result in
the scope VirtualRegister result operand.
Added Phantoms where appropriate to keep the Scope register alive in places where
it use is optimized away, but where the baseline JIT would need to use its value.
Eliminated uses of JSStack::ScopeChain.
- dfg/DFGStackLayoutPhase.cpp:
(JSC::DFG::StackLayoutPhase::run):
Make sure that the scope register stack location is allocated using the same place
that the codeBlock expects.
- dfg/DFGStrengthReductionPhase.cpp:
(JSC::DFG::StrengthReductionPhase::handleNode):
Allow strength reduction of Flush to skip of GetScope nodes looking for a prior
corresponding SetLocal.
(JSC::ExecState::scope):
(JSC::ExecState::setScope):
Added new scope() and setScope() helpers that take a VirtualRegister offset.
- interpreter/Interpreter.cpp:
(JSC::eval):
Changed eval() to get the scope from the caller's scope register instead of from the
temporary frame created for eval.
- interpreter/Interpreter.cpp:
(JSC::Interpreter::unwind):
Changed unwind() to manipulate the scope n the allocated register instead of from the
call frame slot.
- interpreter/StackVisitor.cpp:
(JSC::StackVisitor::readNonInlinedFrame):
(JSC::StackVisitor::readInlinedFrame):
- interpreter/StackVisitor.h:
(JSC::StackVisitor::Frame::callee):
(JSC::StackVisitor::Frame::scope): Deleted.
Eliminated the scope member as it needed to change and no StackVisitor users use it.
(JSC::operationPushNameScope):
(JSC::operationPushWithScope):
(JSC::JSNameScope::create):
(JSC::JSWithScope::create): Deleted.
- llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
Deleted JSNameScope::create() and JSWithScope::create() flavors tht used the ScopeChain slot
in the CallFrame header. Changed the only user of these function, op_push_name_scope and
op_push_with_scope helpers, to use the remaining create variants that require explicit scope.
Those operations get the scope from the register pointed to by their scope operands.
- llint/LowLevelInterpreter32_64.asm:
- llint/LowLevelInterpreter64.asm:
Changed resolveScope to use the allocated register.
LayoutTests:
New test that sets a breakpoint in a callee of a DFG caller. While stopped in the
breakpoint, it modifies a global via the scope chain of the DFG caller as well as
a local of the DFG caller.
- inspector-protocol/debugger/resources/breakpoint.js:
(notInlineable3):
(dfgWithoutInline3):
- inspector-protocol/debugger/setBreakpoint-dfg-callee-and-examine-dfg-local-expected.txt: Added.
- inspector-protocol/debugger/setBreakpoint-dfg-callee-and-examine-dfg-local.html: Added.
