[Win32] "-fwrapv" disappears from ccflags with gcc version 10. #18739
Description
This had me a bit puzzled, but I guess that "$(GCCVER1)" geq "5" is doing string comparison, and is therefore untrue when $(GCCVER1) is in the range 10 .. 50.
(I look forward to seeing -fwrapv pop up gain when gcc-51 is released ;-)
AFAICT, the absence of -fwrapv makes no difference, and I do wonder if it was ever actually needed on Windows (or anywhere else).
Is there a simple test case for determining this ?
I'm running Windows 7. Might that make a difference ?
I've read through #13690, but found it difficult to follow, and I haven't yet managed to reproduce a case that needs that switch.
My belief is that -fwrapv is the default behaviour anyway.
If that view is correct, then I would think that the need to specify that switch must represent a bug in -fwrapv (unless, of course, it is being used to override an earlier instance of -ftrapv).
I've also built 5.33.9 (current devel, released today) without -fwrapv, using gcc-7.2.0, and all tests passed.
C:\comp-aux\perl-5.33.9\win32>..\perl -I..\lib -V:archname
archname='MSWin32-x64-multi-thread';
C:\comp-aux\perl-5.33.9\win32>..\perl -I..\lib -V:gccversion
gccversion='7.2.0';
C:\comp-aux\perl-5.33.9\win32>..\perl -I..\lib -V:ccflags
ccflags=' -DWIN32 -DWIN64 -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -D__USE_MINGW_ANSI_STDIO -fno-strict-aliasing -mms-bitfields';
C:\comp-aux\perl-5.33.9\win32>..\perl -I..\lib -le "print $]"
5.033009
AFAICT perl will no longer build with gcc-4 on Windows.
With mingw-w64 port of gcc-4.9.2, I get unresolved symbols during linking when the Win32 (core) module is being built.
I guess there's really nothing wrong with specifying -fwrapv if it's not needed.
Perhaps, since perl is no longer buildable with gcc-4.3 or earlier, all we need do is hard code the -fwrapv switch permanently into the GNUmakefile ?
Or do we really want to include that switch only when it's needed ?
Here's the full 'perl -V' output of the 7.2.0 build:
C:\comp-aux\perl-5.33.9\win32>..\perl -I..\lib -V
Summary of my perl5 (revision 5 version 33 subversion 9) configuration:
Platform:
osname=MSWin32
osvers=6.1.7601
archname=MSWin32-x64-multi-thread
uname=''
config_args='undef'
hint=recommended
useposix=true
d_sigaction=undef
useithreads=define
usemultiplicity=define
use64bitint=define
use64bitall=undef
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
Compiler:
cc='gcc'
ccflags =' -DWIN32 -DWIN64 -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT
-DPERL_IMPLICIT_SYS -DUSE_PERLIO -D__USE_MINGW_ANSI_STDIO -fno-strict-aliasing -
mms-bitfields'
optimize='-s -O2'
cppflags='-DWIN32'
ccversion=''
gccversion='7.2.0'
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='double'
nvsize=8
Off_t='long long'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries:
ld='g++'
ldflags ='-s -L"C:\_64\blead-5.33.9\lib\CORE" -L"C:\_64\gcc-mingw-720\mingw6
4\lib" -L"C:\_64\gcc-mingw-720\mingw64\x86_64-w64-mingw32\lib" -L"C:\_64\gcc-min
gw-720\mingw64\lib\gcc\x86_64-w64-mingw32\7.2.0"'
libpth=C:\_64\gcc-mingw-720\mingw64\lib C:\_64\gcc-mingw-720\mingw64\x86_64-
w64-mingw32\lib C:\_64\gcc-mingw-720\mingw64\lib\gcc\x86_64-w64-mingw32\7.2.0 C:
\_64\gcc-mingw-720\mingw64\x86_64-w64-mingw32\lib C:\_64\msys_720\1.0\local\lib
C:\_64\gcc-mingw-720\mingw64\lib\gcc\x86_64-w64-mingw32\7.2.0
libs= -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 -ladvapi3
2 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr -lwinmm -lversio
n -lodbc32 -lodbccp32 -lcomctl32
perllibs= -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 -ladv
api32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr -lwinmm -lve
rsion -lodbc32 -lodbccp32 -lcomctl32
libc=
so=dll
useshrplib=true
libperl=libperl533.a
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_win32.xs
dlext=dll
d_dlsymun=undef
ccdlflags=' '
cccdlflags=' '
lddlflags='-mdll -s -L"C:\_64\blead-5.33.9\lib\CORE" -L"C:\_64\gcc-mingw-720
\mingw64\lib" -L"C:\_64\gcc-mingw-720\mingw64\x86_64-w64-mingw32\lib" -L"C:\_64\
gcc-mingw-720\mingw64\lib\gcc\x86_64-w64-mingw32\7.2.0"'
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_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_PERLIO
USE_PERL_ATOF
Built under MSWin32
Compiled at Apr 21 2021 10:22:57
@INC:
..\lib
C:/comp-aux/perl-5.33.9/lib
Cheers,
Rob