modfl() is horribly broken in MinGW-W64

[p5pRT]

Migrated from rt.perl.org#128673 (status was 'open')

Searchable as RT128673$

[p5pRT]

From @dcollinsn

Hello

Found another one. In builds of blead using the MinGW-W64 toolchain for x86_64, with long doubles enabled, calls to modfl() will segfault the perl interpreter. This is not a perlbug, the below C test crashes (segfaults) in the call to modfl()​:

--- modftest.c

#include <tgmath.h>
#include <stdio.h>

int main() {
  long double a, b, c;
  a = 1.76;
  __mingw_printf("About to call modfl(1.76, &b)\n");
  c = modfl(a, &b);
  __mingw_printf("Alive. b = %Le, c = %Le\n", b, c);
  return 0;
}

__END__

However, as a result, ext\POSIX\t\math.t *crashes* after test 28​:

../ext/POSIX/t/math.t (Wstat​: 65280 Tests​: 28 Failed​: 0)
  Non-zero exit status​: 255
  Parse errors​: No plan found in TAP output

This has been open upstream for about a year. There is a patch in the upstream ticket, which I have bumped. You can find the ticket here​:

https://sourceforge.net/p/mingw-w64/bugs/478/

versions, for fun​:

W​:\buildbot\windows1\win64-mingww64-4_9_3-ld\build>gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=C​:/mingw-w64/x86_64-4.9.3/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/4.9.3/lto-wrapper.exe
Target​: x86_64-w64-mingw32
Configured with​: ../../../src/gcc-4.9.3/configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --prefix=/mingw64 --with-sysroot=/c/mingw493/x86_64-493-posix-seh-rt_v4-rev1/mingw64 --with-gxx-include-dir=/mingw64/x86_64-w64-mingw32/include/c++ --enable-shared --enable-static --disable-multilib --enable-languages=c,c++,fortran,objc,obj-c++,lto --enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-libatomic --enable-lto --enable-graphite --enable-checking=release --enable-fully-dynamic-string --enable-version-specific-runtime-libs --disable-isl-version-check --disable-cloog-version-check --disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-as --with-gnu-ld --with-arch=nocona --with-tune=core2 --with-libiconv --with-system-zlib --with-gmp=/c/mingw493/prerequisites/x86_64-w64-mingw32-static --with-mpfr=/c/mingw493/prerequisites/x86_64-w64-mingw32-static --with-mpc=/c/mingw493/prerequisites/x86_64-w64-mingw32-static --with-isl=/c/mingw493/prerequisites/x86_64-w64-mingw32-static --with-cloog=/c/mingw493/prerequisites/x86_64-w64-mingw32-static --enable-cloog-backend=isl --with-pkgversion='x86_64-posix-seh-rev1, Built by MinGW-W64 project' --with-bugurl=http​://sourceforge.net/projects/mingw-w64 CFLAGS='-O2 -pipe -I/c/mingw493/x86_64-493-posix-seh-rt_v4-rev1/mingw64/opt/include -I/c/mingw493/prerequisites/x86_64-zlib-static/include -I/c/mingw493/prerequisites/x86_64-w64-mingw32-static/include' CXXFLAGS='-O2 -pipe -I/c/mingw493/x86_64-493-posix-seh-rt_v4-rev1/mingw64/opt/include -I/c/mingw493/prerequisites/x86_64-zlib-static/include -I/c/mingw493/prerequisites/x86_64-w64-mingw32-static/include' CPPFLAGS= LDFLAGS='-pipe -L/c/mingw493/x86_64-493-posix-seh-rt_v4-rev1/mingw64/opt/lib -L/c/mingw493/prerequisites/x86_64-zlib-static/lib -L/c/mingw493/prerequisites/x86_64-w64-mingw32-static/lib '
Thread model​: posix
gcc version 4.9.3 (x86_64-posix-seh-rev1, Built by MinGW-W64 project)

Summary of my perl5 (revision 5 version 25 subversion 3) configuration​:

  Platform​:
  osname=MSWin32
  osvers=10.0
  archname=MSWin32-x64-multi-thread-ld
  uname=''
  config_args='undef'
  hint=recommended
  useposix=true
  d_sigaction=undef
  useithreads=define
  usemultiplicity=define
  use64bitint=define
  use64bitall=undef
  uselongdouble=define
  usemymalloc=n
  bincompat5005=undef
  Compiler​:
  cc='gcc'
  ccflags =' -s -O2 -DWIN32 -DWIN64 -DCONSERVATIVE -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -D__USE_MINGW_ANSI_STDIO -fwrapv -fno-strict-aliasing -mms-bitfields'
  optimize='-s -O2'
  cppflags='-DWIN32'
  ccversion=''
  gccversion='4.9.3'
  gccosandvers=''
  intsize=4
  longsize=4
  ptrsize=8
  doublesize=8
  byteorder=12345678
  doublekind=3
  d_longlong=define
  longlongsize=8
  d_longdbl=define
  longdblsize=16
  longdblkind=3
  ivtype='long long'
  ivsize=8
  nvtype='long double'
  nvsize=16
  Off_t='long long'
  lseeksize=8
  alignbytes=8
  prototype=define
  Linker and Libraries​:
  ld='g++'
  ldflags ='-s -L"c​:\perl\lib\CORE" -L"C​:\mingw-w64\x86_64-4.9.3\mingw64\lib"'
  libpth=C​:\mingw-w64\x86_64-4.9.3\mingw64\lib
  libs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
  perllibs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
  libc=
  so=dll
  useshrplib=true
  libperl=libperl525.a
  gnulibc_version=''
  Dynamic Linking​:
  dlsrc=dl_win32.xs
  dlext=dll
  d_dlsymun=undef
  ccdlflags=' '
  cccdlflags=' '
  lddlflags='-mdll -s -L"c​:\perl\lib\CORE" -L"C​:\mingw-w64\x86_64-4.9.3\mingw64\lib"'

Characteristics of this binary (from libperl)​:
  Compile-time options​:
  HAS_TIMES
  HAVE_INTERP_INTERN
  MULTIPLICITY
  PERLIO_LAYERS
  PERL_COPY_ON_WRITE
  PERL_DONT_CREATE_GVSV
  PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
  PERL_IMPLICIT_CONTEXT
  PERL_IMPLICIT_SYS
  PERL_MALLOC_WRAP
  PERL_OP_PARENT
  PERL_PRESERVE_IVUV
  USE_64_BIT_INT
  USE_ITHREADS
  USE_LARGE_FILES
  USE_LOCALE
  USE_LOCALE_COLLATE
  USE_LOCALE_CTYPE
  USE_LOCALE_NUMERIC
  USE_LOCALE_TIME
  USE_LONG_DOUBLE
  USE_PERLIO
  USE_PERL_ATOF
  Built under MSWin32
  Compiled at Jul 19 2016 16​:34​:24
  @​INC​:
  W​:/buildbot/windows1/win64-mingww64-4_9_3-ld/build/lib
  .

--
Respectfully,
Dan Collins

[p5pRT]

From @tonycoz

On Tue Jul 19 14​:20​:33 2016, dcollinsn@​gmail.com wrote​:

Hello

Found another one. In builds of blead using the MinGW-W64 toolchain
for x86_64, with long doubles enabled, calls to modfl() will segfault
the perl interpreter. This is not a perlbug, the below C test crashes
(segfaults) in the call to modfl()​:

This came up in #14865 and resulted in #14876.

Tony

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[toddr]

@tonycoz are you saying this is resolved?

[tonycoz]

It's fixed upstream in https://sourceforge.net/p/mingw-w64/mingw-w64/ci/9a2479858b3bb7df36a09c4472fa1adca7e84f19/

Closing.