All DFG helpers that may call out to arbitrary JS code must know where they
were called from due to inlining and call stack walking
https://bugs.webkit.org/show_bug.cgi?id=77070
<rdar://problem/10750834>
Source/JavaScriptCore:
Reviewed by Geoff Garen.
Changed the DFG to always record a code origin index in the tag of the argument
count (which we previously left blank for the benefit of LLInt, but is still
otherwise unused by the DFG), so that if we ever need to walk the stack accurately
we know where to start. In particular, if the current ExecState* points several
semantic call frames away from the true semantic call frame because we had
performed inlining, having the code origin index recorded means that we can reify
those call frames as necessary to give runtime/library code an accurate view of
the current JS state.
This required several large but mechanical changes:
- Calling a function from the DFG now plants a store32 instruction to store the
code origin index. But the indices of code origins were previously picked by
the DFG::JITCompiler after code generation completed. I changed this somewhat;
even though the code origins are put into the CodeBlock after code gen, the
code gen now knows a priori what their indices will be. Extensive assertions
are in place to ensure that the two don't get out of sync, in the form of the
DFG::CallBeginToken. Note that this mechanism has almost no effect on JS calls;
those don't need the code origin index set in the call frame because we can get
it by doing a binary search on the return PC.
- Stack walking now always calls trueCallFrame() first before beginning the walk,
since even the top call frame may be wrong. It still calls trueCallerFrame() as
before to get to the next frame, though trueCallerFrame() is now mostly a
wrapper around callerFrame()->trueCallFrame().
- Because the mechanism for getting the code origin of a call frame is bimodal
(either the call frame knows its code origin because the code origin index was
set, or it's necessary to use the callee frame's return PC), I put in extra
mechanisms to determine whether your caller, or your callee, corresponds to
a call out of C++ code. Previously we just had the host call flag, but this is
insufficient as it does not cover the case of someone calling JSC::call(). But
luckily we can determine this just by looking at the return PC: if the return
PC is in range of the ctiTrampiline, then two things are true: this call
frame's PC will tell you nothing about where you came from in your caller, and
the caller already knows where it's at because it must have set the code origin
index (unless it's not DFG code, in which case we don't care because there is
no inlining to worry about).
- During testing this revealed a simple off-by-one goof in DFG::ByteCodeParser's
inlining code, so I fixed it.
- Finally because I was tired of doing random #if's for checking if I should be
passing around an Instruction* or a ReturnAddressPtr, I created a class called
AbstractPC that holds whatever notion of a PC is appropriate for the current
execution environment. It's designed to work gracefully even if both the
interpreter and the JIT are compiled in, and should integrate nicely with the
LLInt.
This is neutral on all benchmarks and fixes some nasty corner-case regressions of
evil code that uses combinations of getters/setters and function.arguments.
(JSC::CodeBlock::codeOrigin):
(CodeBlock):
- dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::handleInlining):
(JSC::DFG::JITCompiler::link):
(CallBeginToken):
(JSC::DFG::CallBeginToken::CallBeginToken):
(JSC::DFG::CallBeginToken::assertCodeOriginIndex):
(JSC::DFG::CallBeginToken::assertNoCodeOriginIndex):
(DFG):
(JSC::DFG::CallExceptionRecord::CallExceptionRecord):
(CallExceptionRecord):
(JSC::DFG::JITCompiler::JITCompiler):
(JITCompiler):
(JSC::DFG::JITCompiler::nextCallBeginToken):
(JSC::DFG::JITCompiler::beginCall):
(JSC::DFG::JITCompiler::notifyCall):
(JSC::DFG::JITCompiler::addExceptionCheck):
(JSC::DFG::JITCompiler::addFastExceptionCheck):
():
(JSC::DFG::tryBuildGetByIDList):
(JSC::DFG::SpeculativeJIT::appendCallWithExceptionCheck):
- dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::emitCall):
- dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::emitCall):
- interpreter/AbstractPC.cpp: Added.
(JSC):
(JSC::AbstractPC::AbstractPC):
- interpreter/AbstractPC.h: Added.
(JSC):
(AbstractPC):
(JSC::AbstractPC::AbstractPC):
(JSC::AbstractPC::hasJITReturnAddress):
(JSC::AbstractPC::jitReturnAddress):
(JSC::AbstractPC::hasInterpreterReturnAddress):
(JSC::AbstractPC::interpreterReturnAddress):
(JSC::AbstractPC::isSet):
(JSC::AbstractPC::operator!):
():
- interpreter/CallFrame.cpp:
(JSC):
(JSC::CallFrame::trueCallFrame):
(JSC::CallFrame::trueCallerFrame):
(JSC::ExecState::abstractReturnPC):
(JSC::ExecState::codeOriginIndexForDFGWithInlining):
(ExecState):
(JSC::ExecState::trueCallFrame):
(JSC::ExecState::trueCallFrameFromVMCode):
- interpreter/Interpreter.cpp:
(JSC::Interpreter::retrieveArgumentsFromVMCode):
(JSC::Interpreter::retrieveCallerFromVMCode):
(JSC::Interpreter::findFunctionCallFrameFromVMCode):
- interpreter/Interpreter.h:
(Interpreter):
():
(JSC):
():
(JSC):
(JSC::returnAddressIsInCtiTrampoline):
(JSC::JSFunction::argumentsGetter):
(JSC::JSFunction::callerGetter):
(JSC::JSFunction::getOwnPropertyDescriptor):
LayoutTests:
Reviewed by Geoff Garen.
- fast/js/dfg-inline-arguments-use-directly-from-inlined-code-expected.txt: Added.
- fast/js/dfg-inline-arguments-use-directly-from-inlined-code.html: Added.
- fast/js/dfg-inline-arguments-use-from-all-the-places-broken-expected.txt: Added.
- fast/js/dfg-inline-arguments-use-from-all-the-places-broken.html: Added.
- fast/js/dfg-inline-arguments-use-from-all-the-places-expected.txt: Added.
- fast/js/dfg-inline-arguments-use-from-all-the-places.html: Added.
- fast/js/dfg-inline-arguments-use-from-getter-expected.txt: Added.
- fast/js/dfg-inline-arguments-use-from-getter.html: Added.
- fast/js/script-tests/dfg-inline-arguments-use-directly-from-inlined-code.js: Added.
(foo):
(bar):
(argsToStr):
- fast/js/script-tests/dfg-inline-arguments-use-from-all-the-places-broken.js: Added.
(foo):
(fuzz):
(getter):
(bar):
(argsToStr):
- fast/js/script-tests/dfg-inline-arguments-use-from-all-the-places.js: Added.
(foo):
(fuzz):
(getter):
(bar):
(argsToStr):
- fast/js/script-tests/dfg-inline-arguments-use-from-getter.js: Added.
(foo):
(bar):
(argsToStr):
