[webkit-reviews] review denied: [Bug 184316] Add pointer profiling support to the DFG and supporting files. : [Attachment 337245] proposed patch.

[bugzilla-daemon at webkit.org]

Filip Pizlo <fpizlo at apple.com> has denied Mark Lam <mark.lam at apple.com>'s
request for review:
Bug 184316: Add pointer profiling support to the DFG and supporting files.
https://bugs.webkit.org/show_bug.cgi?id=184316

Attachment 337245: proposed patch.

https://bugs.webkit.org/attachment.cgi?id=337245&action=review




--- Comment #4 from Filip Pizlo <fpizlo at apple.com> ---
Comment on attachment 337245
  --> https://bugs.webkit.org/attachment.cgi?id=337245
proposed patch.

View in context: https://bugs.webkit.org/attachment.cgi?id=337245&action=review

> Source/JavaScriptCore/b3/air/AirCCallSpecial.cpp:137
> +	   jit.call(scratchRegister, B3CCallPtrTag);

This might be OK, but can you file a bug for passing the ptrtag to the
CCallValue, so that the client of B3 can select what tag is used for each call
they emit?

> Source/JavaScriptCore/dfg/DFGOSRExit.cpp:755
> +#if USE(POINTER_PROFILING)
> +	       void* oldEntrySP = cpu.fp<uint8_t*>() +
sizeof(CallerFrameAndPC);
> +	       void* newEntrySP = cpu.fp<uint8_t*>() +
inlineCallFrame->returnPCOffset() + sizeof(void*);
> +	       returnPC = retagCodePtr(returnPC,
bitwise_cast<PtrTag>(oldEntrySP), bitwise_cast<PtrTag>(newEntrySP));
> +#endif

Wait... won't this fail miserably if the OSR exit is reused at a different
stack height?