Bug 108541

Summary:	Convert x86 assembly stub to PIC to fix linking with lld
Product:	Mesa	Reporter:	Christian Weisgerber <naddy>
Component:	Mesa core	Assignee:	mesa-dev
Status:	RESOLVED MOVED	QA Contact:	mesa-dev
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	Other
OS:	OpenBSD
Whiteboard:
i915 platform:		i915 features:
Attachments:	Convert entry_x86_tsd.h to PIC adapted libglvnd x86 tsd changes

Description Christian Weisgerber 2018-10-24 17:38:19 UTC

Created attachment 142177 [details] [review]
Convert entry_x86_tsd.h to PIC

The x86 assembly language stub in src/mapi/entry_x86_tsd.h does not generate PIC (position-independent code). This causes text relocations, which are by default treated as an error by LLVM's lld linker (now used by FreeBSD and OpenBSD) when building a shared library.

/usr/bin/ld: error: can't create dynamic relocation R_386_32 against symbol: _glapi_Dispatch in readonly segment; recompile object files with -fPIC
>>> defined in .libs/shared_glapi_libglapi_la-u_current.o
>>> referenced by entry.c
>>>               .libs/shared_glapi_libglapi_la-entry.o:(.text+0x1)

The accompanying minimal diff remedies this by generating PIC code.  This is mostly copied from the neighboring entry_x86_tls.h.

Comment 1 Jonathan Gray 2018-10-31 06:48:23 UTC

Created attachment 142297 [details] [review]
adapted libglvnd x86 tsd changes

Comment 2 Jonathan Gray 2018-10-31 06:51:00 UTC

Your patch segfaults at runtime, an approach based on libglvnd x86 tsd changes seems to work however.

https://github.com/NVIDIA/libglvnd/commit/9a17198be3622ffa00f9db36e6b55773d4dcf596#diff-ac251356bcfe8971786926ffc9660d69

Comment 3 ytht.net 2019-09-13 17:24:25 UTC

FYI, I create a merge request on behalf of Jonathan Gray:

https://gitlab.freedesktop.org/mesa/mesa/merge_requests/1974

Comment 4 GitLab Migration User 2019-09-18 20:27:26 UTC

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