NO_WCAST_ALIGN. The headers of the standard C++ library are
not 64-bit clean and trigger the warning. This prevents use
of WARNS>=4 on ia64 for example.
Unfortunately there are two slight problems with that:
- Yacc and lex might generate code that generates warnings because of
this. Require yacc and lex to be rebuilt during bootstrap. I'm not
incrementing __FreeBSD_version here, because I assume someone else
will do this eventually.
- When running `make buildkernel', it uses share/mk from the source
treeo to build aicasm. Because aicasm also depends on lex, this would
break. Lower WARNS to 5 for now. We should just increment it to 6
again somewhere in the very far future.
The segfaults when using SSP seem to be a gcc bug, a patch is available
in the gcc bugzilla, and will be imported once it's committed
into the official gcc tree.
- It is opt-out for now so as to give it maximum testing, but it may be
turned opt-in for stable branches depending on the consensus. You
can turn it off with WITHOUT_SSP.
- WITHOUT_SSP was previously used to disable the build of GNU libssp.
It is harmless to steal the knob as SSP symbols have been provided
by libc for a long time, GNU libssp should not have been much used.
- SSP is disabled in a few corners such as system bootstrap programs
(sys/boot), process bootstrap code (rtld, csu) and SSP symbols themselves.
- It should be safe to use -fstack-protector-all to build world, however
libc will be automatically downgraded to -fstack-protector because it
breaks rtld otherwise.
- This option is unavailable on ia64.
Enable GCC stack protection (aka Propolice) for kernel:
- It is opt-out for now so as to give it maximum testing.
- Do not compile your kernel with -fstack-protector-all, it won't work.
Submitted by: Jeremie Le Hen <jeremie@le-hen.org>
This time, change the default CFLAGS to match the simple defaults that
the tinderboxes use. That is, don't use -fno-strict-aliasing by default.
My last attempt to re-anable -Werror gave me a lesson in what strict
aliasing is all about. There was code in libthr that wasn't 64-bit clean.
The default use of -fno-strict-aliasing hid that.
By using -fno-strict-aliasing by default we were choosing to ignore
problems in code which had the potential to shoot ourselves in the
foot. Sometimes it would be the 64-bit foot. I have both feet. The left
ones are 32 bits and the right ones are 64 bits. Don't ask about my
endian orientation. :-)
The -fno-strict-aliasing compiler arg can still be used if NO_STRING_ALIASING
is define in make.
We are early in the FreeBSD 8 development, so we have the opportunity to
wait and see if this works for us. I am sure that people will complain.
We can easily revert this. All I ask is that we take sides: clean code or
not. YMMV.
Note that by using -fno-strict-aliasing the build won't actually break.
Only where WARNS is set (and -Werror is used) will a compiler warning break
the build. The use of WARNS levels implies (to me at least) that the
developer has taken some care to make the code pass basic checks. This
commit makes those checks just a little bit more strict.
obstacle to enabling -Werror. I'll continue to work on cleaning up the
code so that we can keep this enabled.
If the tinderboxes would just use the default CFLAGS set in this file,
all would be fine and we'd be able to make use of -Werror.
compiler invocation. This is just to help get over the hump of people
tracking down bugs that may cross the GCC 4.2 upgrade.
It is envisioned that this option goes away after a suitable amount
of time.
There are new warnings that kill the build otherwise.
Disable pointer destination sign mismatch warning alltogether. Our tree
is in no shape to have that enabled yet.
of C in which the program or library is written.
Note that this is *not* intended to be used across the whole tree. It
is intended to be used for individual libraries or programs which use
specific language features which the compiler must know about in order
to produce correct warnings at high WARNS levels.
MFC after: 1 month
Intel C/C++ compiler (lang/icc) to build the kernel.
The icc CPUTYPE CFLAGS use icc v7 syntax, icc v8 moans about them, but
doesn't abort. They also produce CPU specific code (new instructions
of the CPU, not only CPU specific scheduling), so if you get coredumps
with signal 4 (SIGILL, illegal instruction) you've used the wrong
CPUTYPE.
Incarnations of this patch survive gcc compiles and my make universe.
I use it on my desktop.
To use it update share/mk, add
/usr/local/intel/compiler70/ia32/bin (icc v7, works)
or
/usr/local/intel_cc_80/bin (icc v8, doesn't work)
to your PATH, make sure you have a new kernel compile directory
(e.g. MYKERNEL_icc) and run
CFLAGS="-O2 -ip" CC=icc make depend
CFLAGS="-O2 -ip" CC=icc make
in it.
Don't compile with -ipo, the build infrastructure uses ld directly to
link the kernel and the modules, but -ipo needs the link step to be
performed with Intel's linker.
Problems with icc v8:
- panic: npx0 cannot be emulated on an SMP system
- UP: first start of /bin/sh results in a FP exception
Parts of this commit contains suggestions or submissions from
Marius Strobl <marius@alchemy.franken.de>.
Reviewed by: silence on -arch
Submitted by: netchild
uses alloca() and alloca is impossible to implement as a callable function
on amd64. It has to be a compiler builtin. Note that the bigger problem
is that libc is not c99 clean internally.
in which the source code is written. This is controlled by the CSTD
variable, which can have one of the following values:
- "k&r" => -traditional
- "c89" or "c90" => -std=iso9899:1990
- "c94" or "c95" => -std=iso9899:199409
- "c99" => -std=iso9899:1999
The corresponding option is added to CFLAGS regardless of WARNS level.
This also removes -ansi from WARNS level 6, but adds -Wno-long-long to
work around a weird gcc bug (-ansi, which is supposedly equivalent to
-std=iso9899:1990, seems to turn long long warnings off instead of on)
If CSTD is undefined, CFLAGS are unchanged except for the -ansi /
-Wno-long-long change mentioned above for WARNS level 6.
FreeBSD. This method attempts to centralize all the necessary hacks
or work arounds in one of two places in the tree (src/Makefile.inc1
and src/tools/build). We build a small compatibility library
(libbuild.a) as well as selectively installing necessary include
files. We then include this directory when building host binaries.
This removes all the past release compatibilty hacks from various
places in the tree. We still build on tip of stable and current. I
will work with those that want to support more, although I anticipate
it will just work.
Many thanks to ru@, obrien@ and jhb@ for providing valuable input at
various stage of implementation, as well as for working together to
positively effect a change for the better.
glibc which is externally maintained, so GCC ships with these
warnings turned off by default. This is also consistent with
the src/contrib/gcc/c-lex.c,v 1.2 change.
have the __FBSDID() macro in <sys/cdefs.h>. Fix this once and for all
for tools that need to be bootstrapped.
PR: bin/36747
MFC after: 3 days
Prodded by: obrien
