| Message ID | 20210331182514.GR1179226@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | rs6000: Fix up libgcc ABI when built with --with-long-double-format=ieee [PR97653] | expand |
Hi! On Wed, Mar 31, 2021 at 08:25:14PM +0200, Jakub Jelinek wrote: > __floatunditf and __fixtfdi and a couple of other libgcc{.a,_s.so} > entrypoints for backwards compatibility should mean IBM double double > handling (i.e. IFmode), gcc emits such calls for that format and > form IEEE long double emits *kf* instead. > When gcc is configured without --with-long-double-format=ieee , > everything is fine, but when it is not, we need to compile those > libgcc sources with -mno-gnu-attribute -mabi=ibmlongdouble. > The following snippet in libgcc/config/rs6000/t-linux was attempting > to ensure that, and for some routines it works fine (e.g. for _powitf2). > But, due to 4 different types of bugs it doesn't work for most of those > functions, which means that in --with-long-double-format=ieee > configured gcc those *tf* entrypoints instead handle the long double > arguments as if they were KFmode. > > The bugs are: > 1) the first few objs properly use $(objext) as suffix, but > several other contain a typo and use $(object) instead, > which is a variable that isn't set to anything, so we don't > add .o etc. extensions Msybe we should use the --warn-undefined-variables make flag? > 2) while unsigned fix are properly called _fixuns*, unsigned float > are called _floatun* (without s), but the var was using there > the extra s and so didn't match > 3) the variable didn't cover any of the TF <-> TI conversions, > only TF <-> DI conversions > 4) nothing in libgcc_s.so was handled, as those object files are > called *_s.o rather than *.o and IBM128_SHARED_OBJS used wrong > syntax of the GNU make substitution reference, which should be > $(var:a=b) standing for $(patsubst a,b,$(var)) but it used > $(var:a:b) instead That is POSIX, not a GNU invention :-) > PR target/97653 > * config/rs6000/t-linux (IBM128_STATIC_OBJS): Fix spelling, use > $(objext) instead of $(object). Use _floatunditf instead of > _floatunsditf. Add tf <-> ti conversion objects. > (IBM128_SHARED_OBJS): Use proper substitution reference syntax. Okay for trunk. Thank you! Segher
--- libgcc/config/rs6000/t-linux.jj 2020-12-04 08:08:06.556434569 +0100 +++ libgcc/config/rs6000/t-linux 2021-03-31 14:20:50.953852864 +0200 @@ -11,10 +11,12 @@ HOST_LIBGCC2_CFLAGS += -mno-minimal-toc # the IBM extended double format. Also turn off gnu attributes on the static # modules. IBM128_STATIC_OBJS = ibm-ldouble$(objext) _powitf2$(objext) \ - ppc64-fp$(objext) _divtc3$(object) _multc3$(object) \ - _fixtfdi$(object) _fixunstfdi$(object) \ - _floatditf$(objext) _floatunsditf$(objext) -IBM128_SHARED_OBJS = $(IBM128_STATIC_OBJS:$(objext):_s$(objext)) + ppc64-fp$(objext) _divtc3$(objext) _multc3$(objext) \ + _fixtfdi$(objext) _fixunstfdi$(objext) \ + _floatditf$(objext) _floatunditf$(objext) \ + _fixtfti$(objext) _fixunstfti$(objext) \ + _floattitf$(objext) _floatuntitf$(objext) +IBM128_SHARED_OBJS = $(IBM128_STATIC_OBJS:$(objext)=_s$(objext)) IBM128_OBJS = $(IBM128_STATIC_OBJS) $(IBM128_SHARED_OBJS) IBM128_CFLAGS = -Wno-psabi -mabi=ibmlongdouble -mno-gnu-attribute
Hi! __floatunditf and __fixtfdi and a couple of other libgcc{.a,_s.so} entrypoints for backwards compatibility should mean IBM double double handling (i.e. IFmode), gcc emits such calls for that format and form IEEE long double emits *kf* instead. When gcc is configured without --with-long-double-format=ieee , everything is fine, but when it is not, we need to compile those libgcc sources with -mno-gnu-attribute -mabi=ibmlongdouble. The following snippet in libgcc/config/rs6000/t-linux was attempting to ensure that, and for some routines it works fine (e.g. for _powitf2). But, due to 4 different types of bugs it doesn't work for most of those functions, which means that in --with-long-double-format=ieee configured gcc those *tf* entrypoints instead handle the long double arguments as if they were KFmode. The bugs are: 1) the first few objs properly use $(objext) as suffix, but several other contain a typo and use $(object) instead, which is a variable that isn't set to anything, so we don't add .o etc. extensions 2) while unsigned fix are properly called _fixuns*, unsigned float are called _floatun* (without s), but the var was using there the extra s and so didn't match 3) the variable didn't cover any of the TF <-> TI conversions, only TF <-> DI conversions 4) nothing in libgcc_s.so was handled, as those object files are called *_s.o rather than *.o and IBM128_SHARED_OBJS used wrong syntax of the GNU make substitution reference, which should be $(var:a=b) standing for $(patsubst a,b,$(var)) but it used $(var:a:b) instead Bootstrapped/regtested on powerpc64le-linux --with-long-double-format=ieee, ok for trunk? 2021-03-31 Jakub Jelinek <jakub@redhat.com> PR target/97653 * config/rs6000/t-linux (IBM128_STATIC_OBJS): Fix spelling, use $(objext) instead of $(object). Use _floatunditf instead of _floatunsditf. Add tf <-> ti conversion objects. (IBM128_SHARED_OBJS): Use proper substitution reference syntax. Jakub