| Message ID | 2340977.15qcfLIRQH@fomalhaut |
|---|---|
| State | New |
| Headers | show |
| Series | [Ada] Fix PR ada/99264 | expand |
Jakub reported that for glibc 2.34 (trunk, unreleased), Richard said it was working for glibc 2.33 (latest release), your commit says "Fix build breakage with latest glibc release" (which is 2.33). What is correct? The change also caused CI test failures in Debian and Ubuntu as seen at https://ci.debian.net/data/autopkgtest/unstable/amd64/a/ahven/10908933/log.gz fail libgnat-10 10.2.1-21 (experimental) https://ci.debian.net/data/autopkgtest/unstable/amd64/a/ahven/10908997/log.gz pass libgnat-10 10.2.1-6 (unstable) Citing Nicolas, """ The symptom "/usr/lib/x86_64-linux-gnu/ada/adalib/ahven/ahven-framework.ali" is obsolete and read-only looks exactly like the scenario described by the Debian Ada Policy. https://people.debian.org/~lbrenta/debian-ada-policy.html Example with a simple dependency chain: libahven depends on libgnat ahven-tests depend on libahven libahven contains, in ahven-framework.ali, a checksum of each source it depends upon, including some libgnat sources. When libgnat changes, libahven must be rebuilt before ahven-tests. Else… The error above is reported when building ahven-tests. It mentions ahven-framework.ali from the libahven-dev package. It actually originates in a change in libgnat. The Debian Ada policy requires that such dependencies are encoded in -dev package names so that dpkg later automatically prevents inconsistent sets of .ali files and related cryptic messages. In the special case of libgnat, built by GCC, there is only one libgnatMAJOR package, containing the files usually expected in libgnatSO and libgnatALI-dev. The sources are not expected to change for a given MAJOR inside unstable. """ Assuming that the change is only required for glibc trunk (2.34), I'll revert that for Debian's package builds for the gcc branches. I'll see what to do if I still need gnat-10 when glibc 2.34 is in use. Otoh, the patch could be conditional on the glibc version detected. Matthias On 3/5/21 12:45 PM, Eric Botcazou wrote: > This fixes the build breakage introduced by the latest glibc release. > > Tested on x86-64/Linux, applied on mainline, 10 and 9 branches. > > > 2021-03-05 Eric Botcazou <ebotcazou@adacore.com> > > PR ada/99264 > * init.c (__gnat_alternate_sta) [Linux]: Remove preprocessor test on > MINSIGSTKSZ and bump size to 32KB. > * libgnarl/s-osinte__linux.ads (Alternate_Stack_Size): Bump to 32KB. >
> Jakub reported that for glibc 2.34 (trunk, unreleased), Richard said it was > working for glibc 2.33 (latest release), your commit says "Fix build > breakage with latest glibc release" (which is 2.33). What is correct? Both I guess, mine is just a bit more forward-looking. ;-) > The symptom > "/usr/lib/x86_64-linux-gnu/ada/adalib/ahven/ahven-framework.ali" is obsolete > and read-only > looks exactly like the scenario described by the Debian Ada Policy. > https://people.debian.org/~lbrenta/debian-ada-policy.html > > Example with a simple dependency chain: > libahven depends on libgnat > ahven-tests depend on libahven > libahven contains, in ahven-framework.ali, a checksum of each source > it depends upon, including some libgnat sources. > When libgnat changes, libahven must be rebuilt before ahven-tests. > Else… > The error above is reported when building ahven-tests. > It mentions ahven-framework.ali from the libahven-dev package. > It actually originates in a change in libgnat. > > The Debian Ada policy requires that such dependencies are encoded in > -dev package names so that dpkg later automatically prevents > inconsistent sets of .ali files and related cryptic messages. > > In the special case of libgnat, built by GCC, there is only one > libgnatMAJOR package, containing the files usually expected in > libgnatSO and libgnatALI-dev. The sources are not expected to change > for a given MAJOR inside unstable. The change is supposed to be binary compatible so not sure what this means. > Assuming that the change is only required for glibc trunk (2.34), I'll > revert that for Debian's package builds for the gcc branches. I'll see what > to do if I still need gnat-10 when glibc 2.34 is in use. Otoh, the patch > could be conditional on the glibc version detected. Too much hassle. Please pester the glibc folks if you have any complaint.
> The change is supposed to be binary compatible so not sure what this > means. Our problem is related with distribution, not with a specific library or its ABI. Imagine that: $VENDOR1 builds GNAT without the fix. $VENDOR2 builds libfoo against GNAT. $administrator installs both. I write bar.adb using foo.adb. $VENDOR1 rebuilds GNAT with the fix modifying s-osinte__linux.ads and s-osinte.ali. $administrator updates GNAT. My next attempt to rebuild bar.adb fails. GNAT (correctly) reports that foo.ali is obsolete and should be rebuilt against the updated s-osinte.ali. I don’t understand the problem because I have never heard of s-osinte.ali. The error happens while building bar.adb, the message mentions libfoo, but the problem originates in an unrelated GNAT update. Even if I did, I could not apply the right fix ($VENDOR2 should rebuild libfoo fory all users). Here VENDOR1=VENDOR2=administrator=Debian wants to prevent this scenario for end users. We must choose to revert the patch or rebuild most Ada packages (the error may affects any recursive dependency of libgnat…). Currently, a stable release is in preparation so the second option has a much higher price.
diff --git a/gcc/ada/init.c b/gcc/ada/init.c index e76aa79c5a8..3ceb1a31b02 100644 --- a/gcc/ada/init.c +++ b/gcc/ada/init.c @@ -579,12 +579,8 @@ __gnat_error_handler (int sig, siginfo_t *si ATTRIBUTE_UNUSED, void *ucontext) #ifndef __ia64__ #define HAVE_GNAT_ALTERNATE_STACK 1 -/* This must be in keeping with System.OS_Interface.Alternate_Stack_Size. - It must be larger than MINSIGSTKSZ and hopefully near 2 * SIGSTKSZ. */ -# if 16 * 1024 < MINSIGSTKSZ -# error "__gnat_alternate_stack too small" -# endif -char __gnat_alternate_stack[16 * 1024]; +/* This must be in keeping with System.OS_Interface.Alternate_Stack_Size. */ +char __gnat_alternate_stack[32 * 1024]; #endif #ifdef __XENO__ diff --git a/gcc/ada/libgnarl/s-osinte__linux.ads b/gcc/ada/libgnarl/s-osinte__linux.ads index f7af00bf5e2..2272f83d68d 100644 --- a/gcc/ada/libgnarl/s-osinte__linux.ads +++ b/gcc/ada/libgnarl/s-osinte__linux.ads @@ -328,7 +328,7 @@ package System.OS_Interface is oss : access stack_t) return int; pragma Import (C, sigaltstack, "sigaltstack"); - Alternate_Stack_Size : constant := 16 * 1024; + Alternate_Stack_Size : constant := 32 * 1024; -- This must be in keeping with init.c:__gnat_alternate_stack Alternate_Stack : aliased char_array (1 .. Alternate_Stack_Size);