[Bug 45199] Many applications and games fail to start/ crash after compiling wine with gcc 8.1.0 and -O2 (GOT/ PIC register load code now emitted at function entry, missing hotpatch signatures)

[wine-bugs at winehq.org]

https://bugs.winehq.org/show_bug.cgi?id=45199

Anastasius Focht <focht at gmx.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Many applications and games |Many applications and games
                   |fail to start/crash after   |fail to start/crash after
                   |compiling wine with gcc     |compiling wine with gcc
                   |8.1.0 and -O2               |8.1.0 and -O2 (GOT/PIC
                   |                            |register load code now
                   |                            |emitted at function entry,
                   |                            |missing hotpatch
                   |                            |signatures)

--- Comment #30 from Anastasius Focht <focht at gmx.net> ---
Hello folks,

there is not much choice here since the change in gcc optimization is perfectly
valid. Of course it harms now if the function being hotpatched has the GOT/PIC
register load code emitted directly at the start of function entry.
Most detour/hookers/patchers can't deal with this kind of entry point code.
This is usually mitigated by using 'ms_hook_prologue' attribute.

You could either collect all the offenders that have no hotpatch entry point
and send in patches that add DECLSPEC_HOTPATCH or use a "no-PIC" build of Wine.

I've built and run Wine with '-fno-PIC' by default since several years.
The GOT/PIC register usage in prolog code is incompatible with multiple copy
protection/DRM schemes (bug 37540, bug 4666 for example) - even hotpatch
doesn't help here, see my explanations. Yes, it can be partially mitigated by
emitting syscall thunks for native API (Wine-Staging has some experimental
patches) but this won't work for non-native/upper layer API.

I guess you could start with a list like comment #11 (apps that make use of
'libtcmalloc') and send in patches that add DECLSPEC_HOTPATCH as needed.

Regards

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