[webkit-reviews] review requested: [Bug 136485] Segmentation fault in WTF::RefPtr<JSC::JITCode>::get() : [Attachment 237560] WIP patch

[bugzilla-daemon at webkit.org]

Akos Kiss <akiss at inf.u-szeged.hu> has asked  for review:
Bug 136485: Segmentation fault in WTF::RefPtr<JSC::JITCode>::get()
https://bugs.webkit.org/show_bug.cgi?id=136485

Attachment 237560: WIP patch
https://bugs.webkit.org/attachment.cgi?id=237560&action=review

------- Additional Comments from Akos Kiss <akiss at inf.u-szeged.hu>
This is a work in progress patch (at least the Changelog has not been
prepared). I think that it may fix not only this bug but
https://bugs.webkit.org/show_bug.cgi?id=132740 and
https://bugs.webkit.org/show_bug.cgi?id=136436 as well. I believe that all
these bugs should be treated together, since they seem to be releated (all of
them are caused by relying on assumptions on how the call stack is laid out).

What it does:
- makeHostFunctionCall (both 32_64 and 64 versions) does not add
sizeof(CallerFrameAndPC) to sp before the call to entry anymore (which made
them rely on calling conventions to fill in caller frame, but also caused the
overlap of the stack area of globalFuncProtoSetter with the caller frame).
- Reorganized makeHostFunctionCall (both 32_64 and 64 versions) a bit to be
more alike (helps future maintenance).
- Moved the setting of the caller frame of execCallee from
JSC::operationCallEval to JIT::compileCallEval (to satisfy what's written in a
comment in JIT::compileOpCall, "Caller always [...] Initializes [...]
CallerFrame")
- Also changed compileCallEval (both 32_64 and 64 versions) not to rely on
calling conventions and keep caller frame and stack of operationCallEval
separate.

Status:
- X86-64/EFL and X86-32/EFL passed all jsc tests correctly
- the ARM64/EFL test run is ongoing, but the test cases that previously caused
problems (the cyclic proto test case included) have been tested manually and
passed
- a Thumb2/EFL test run is also ongoing

Acknowledgements to Michael Saboff and Zan Dobersek, since this patch took
"inspiration" from their patches.