[Bug bootstrap/66038] [5 regression] (stage 2) build/genmatch issue (gcc/hash-table.h|c) with --disable-checking [ introduced by r218976 ]

["kumba at gentoo dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66038

--- Comment #35 from Joshua Kinard <kumba at gentoo dot org> ---
(In reply to rguenther@suse.de from comment #34)
> On Thu, 14 Jan 2016, kumba at gentoo dot org wrote:
> 
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66038
> > 
> > --- Comment #33 from Joshua Kinard <kumba at gentoo dot org> ---
> > The problem may be tied to a particular CFLAG on glibc-n32 MIPS.  I ran our
> > (Gentoo's) stage-building script, and forgot to block gcc-5.3.0 from building,
> > and it ended up completing.  Difference between that script (which builds
> > inside a chroot) is I used saner CFLAGS.
> > 
> > The CFLAGS I am using in my rootfs that fails to build gcc-5.3.0 is:
> > CFLAGS="-O2 -pipe -march=r12k -mtune=r12k -mno-fix-r10000 -mabi=n32 -mplt
> > -fomit-frame-pointer -fforce-addr -fivopts -fmodulo-sched -ftree-vectorize"
> > LDFLAGS="-Wl,-O2 -Wl,-z,now -Wl,-z,relro"
> > 
> > So I'll look at dropping one flag at a time, along with trimming LDFLAGS, and
> > see if I can pin down which one causes ./genmatch --gimple to segfault 
> on N32.
> 
> -fforce-addr is a no-op and -fivopts is enabled at -O2 by default, so
> you can omit those without testing.

It looks like it's my LDFLAGS, specifically with -Wl,-z,now.  I let the build
proceed after removing LDFLAGS from my environment, and once it built genmatch
and ran it w/o a SIGSEGV, I interrupted the build, copied the linking command
for genmatch, and then tested with both -Wl,-z,now and -Wl,-z,relro, and the
relro version runs fine.

# mips64-unknown-linux-gnu-g++ -DIN_GCC -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wno-format -Wmissing-format-attribute -Woverloaded-virtual
-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings
-DHAVE_CONFIG_H -DGENERATOR_FILE -static-libstdc++ -static-libgcc -Wl,-z,now -o
build/genmatchZ3 build/genmatch.o
../build-mips64-unknown-linux-gnu/libcpp/libcpp.a build/errors.o build/vec.o
build/hash-table.o ../build-mips64-unknown-linux-gnu/libiberty/libiberty.a

# build/genmatchZ3 --gimple
Segmentation fault


# mips64-unknown-linux-gnu-g++ -DIN_GCC -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wno-format -Wmissing-format-attribute -Woverloaded-virtual
-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings
-DHAVE_CONFIG_H -DGENERATOR_FILE -static-libstdc++ -static-libgcc -Wl,-z,relro
-o build/genmatchZ4 build/genmatch.o
../build-mips64-unknown-linux-gnu/libcpp/libcpp.a build/errors.o build/vec.o
build/hash-table.o ../build-mips64-unknown-linux-gnu/libiberty/libiberty.a

# build/genmatchZ4 --gimple
(null):0:0 error: --gimple: No such file or directory


Currently using binutils-2.25.1.  Can provide strace runs if needed.