Gtk build of FTL JIT on linux

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Vahag]

Hi, I've been trying to enable FTL JIT for gtk build on Linux. 
I've managed to build JSC with FTL JIT enabled, however jsc fails run time at phase FTLCompile during the call of "llvm->GetPointerToGlobal" function.
Assertion fail happens in LLVM.
File: ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
Assertion: assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN)

[Carlos Alberto Lopez Perez]

Check the bug https://bugs.webkit.org/show_bug.cgi?id=120270 for more information.

[Seo Sanghyeon]

FYI, look at https://bugs.webkit.org/show_bug.cgi?id=133571 which points to https://github.com/pille5/llvm/commits/FTL_fixes_for_EFL for LLVM changes.

Vahag, "FDECFIEncoding = dwarf::DW_EH_PE_pcrel" bit in the patch will fix your assert problem.

[Seo Sanghyeon]

There are two LLVM changes at https://github.com/pille5/llvm/commits/FTL_fixes_for_EFL

I found that the change related to stack map is upstream: http://llvm.org/viewvc/llvm-project?view=revision&revision=214538

The change related to exception frame encoding is not. I am not sure what is the best way to fix the problem, so I commented at http://llvm.org/bugs/show_bug.cgi?id=15356

[Carlos Alberto Lopez Perez]

I think this has been fixed on https://bugs.webkit.org/show_bug.cgi?id=138298

[Csaba Osztrogonác]

Patches in pille5 github repository already landed in LLVM, but not in latest
release. https://trac.webkit.org/changeset/176546 switched jhbuild LLVM module
to use 3.5 release and apply the 2 necessary patch.

If you build llvm with jhbuild (Tools/Scripts/update-webkitgtk-libs llvm),
and then build-webkit --ftl-jit, FTL-JIT works fine.

[Csaba Osztrogonác]

FTL JIT is built by default on GTK since https://trac.webkit.org/changeset/192469