Hi! > > - CONFIG_FUNCTION_GRAPH_TRACER sets it on x86-32 because of a gcc bug > > where the stack gets aligned before the mcount call. This issue > > should be mostly obsolete as most modern compilers now have -mfentry. > > We could make it dependent on CC_USING_FENTRY. > > Yeah. At some point we might even upgrade the compiler requirements to > no longer accept the mcount model. > > I think the fentry model is gcc-4.6.0 and up. Currently I guess we > support gcc-3.2+, which is fairly ridiculous considering that 4.6.0 is > from March, 2011. So it's over five years ago already. > > gcc-3.2.0 is from 2002, I think. At some point you just have to say > "caring about a 15 year old compiler is ridiculous" > > The main reason we have fairly aggressively supported old compilers > tends to be some odder architectures that don't have good support, so > people use various random "this works for me" versions. > > We could easily make the gcc version checks much more strict on x86, > I suspect.
Well, I have fast CPUs, but most of the time they just compile
stuff. Especially bisect is compile-heavy. I suspect going back to
gcc-3.2 would bring me bigger advantages than CPU upgrade...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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