New modref/ipa_modref optimization passes

[David Malcolm]

On Tue, 2020-09-22 at 22:23 +0200, Jan Hubicka wrote:
> > On Tue, 2020-09-22 at 20:39 +0200, Jan Hubicka wrote:
> > > David,
> > > with jit I get the following:
> > > /usr/local/x86_64-pc-linux-gnu/bin/ld: final link failed:
> > > nonrepresentable section on output
> > > collect2: error: ld returned 1 exit status
> > > make[3]: *** [../../gcc/jit/Make-lang.in:121: libgccjit.so.0.0.1]
> > > Error
> > > 
> > > Is there a fix/workaround?
> > 
> > I don't recognize that specific error, but googling suggests it may
> > relate to position-independent code.
> > 
> > Are you configuring with --enable-host-shared ?  This is needed
> > when
> > enabling "jit" in --enable-languages (but slows down the compiler
> > by a
> > few percent, which is why "jit" isn't in "all").
> 
> Yes --enable-languages=all,jit --enable-host-shared.
> I suppose my binutils may show the age, I will check that tomorrow.
> It
> looks like weird error.

FWIW if you do get it to build, you can reproduce the crash via running
this in builddir/gcc:

[gcc] $ PRESERVE_EXECUTABLES= \
          make check-jit \
            RUNTESTFLAGS="-v -v -v jit.exp=test-factorial.c"

[gcc] $ PATH=.:$PATH \
        LD_LIBRARY_PATH=. \
        LIBRARY_PATH=. \
          gdb --args \
            testsuite/jit/test-factorial.c.exe

(taken from 
https://gcc.gnu.org/onlinedocs/jit/internals/index.html#running-the-test-suite
)