BBC: Blead breaks DCMERTENS/C-Blocks-0.42.tar.gz

[andk]

Description

Tests started to fail on 5.35.10. Only non-threaded perls are to be investigated since the package is not thread safe.
Diagnostics output:

C::Blocks internal error: got null pointer for op function! at t/36-API-Creation.t line 13.
# Tests were run but no plan was declared and done_testing() was not seen.
# Looks like your test exited with 2 just after 1.
t/36-API-Creation.t ................. Dubious, test returned 2 (wstat 512, 0x200)
All 1 subtests passed

Bisect leads to

75acd14e43f2ffb698fc7032498f31095b56adb5 is the first bad commit
commit 75acd14e43f2ffb698fc7032498f31095b56adb5
Author: Richard Leach <richardleach@users.noreply.github.com>
Date:   Sun Feb 6 22:52:54 2022 +0000

    Make newSV_type an inline function

Steps to Reproduce

cpan -i DCMERTENS/C-Blocks-0.42.tar.gz

Expected behavior

Should test the distro successfully and install it

Perl configuration

# perl -V output goes here
Summary of my perl5 (revision 5 version 35 subversion 10) configuration:                                  
  Commit id: 75acd14e43f2ffb698fc7032498f31095b56adb5
  Platform:
    osname=linux
    osvers=5.16.0-5-amd64
    archname=x86_64-linux
    uname='linux k93msid 5.16.0-5-amd64 #1 smp preempt debian 5.16.14-1 (2022-03-15) x86_64 gnulinux '
    config_args='-Dprefix=/home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.35.9-88-g75acd14e43/da1c -Dmyhostname=k93msid -Dinstallusrbinperl=n -Uversiononly -Dusedevel -des -Ui_db -Dlibswanted=cl pthread socket inet nsl gdbm dbm malloc dl ld sun m crypt sec util c cposix posix ucb BSD gdbm_compat -Uuseithreads -Uuselongdouble -DEBUGGING=-g'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=undef
    usemultiplicity=undef
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
  Compiler:
    cc='cc'
    ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
    optimize='-O2 -g'
    cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
    ccversion=''
    gccversion='11.2.0'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=3
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='cc'
    ldflags =' -fstack-protector-strong -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib
    libs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.33.so
    so=so
    useshrplib=false
    libperl=libperl.a
    gnulibc_version='2.33'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,-E'
    cccdlflags='-fPIC'
    lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector-strong'


Characteristics of this binary (from libperl): 
  Compile-time options:
    HAS_TIMES
    PERLIO_LAYERS
    PERL_COPY_ON_WRITE
    PERL_DONT_CREATE_GVSV
    PERL_MALLOC_WRAP
    PERL_OP_PARENT
    PERL_PRESERVE_IVUV
    PERL_USE_DEVEL
    USE_64_BIT_ALL
    USE_64_BIT_INT
    USE_LARGE_FILES
    USE_LOCALE
    USE_LOCALE_COLLATE
    USE_LOCALE_CTYPE
    USE_LOCALE_NUMERIC
    USE_LOCALE_TIME
    USE_PERLIO
    USE_PERL_ATOF
  Built under linux
  Compiled at Mar 24 2022 06:04:29
  @INC:
    /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.35.9-88-g75acd14e43/da1c/lib/site_perl/5.35.10/x86_64-linux
    /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.35.9-88-g75acd14e43/da1c/lib/site_perl/5.35.10
    /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.35.9-88-g75acd14e43/da1c/lib/5.35.10/x86_64-linux
    /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.35.9-88-g75acd14e43/da1c/lib/5.35.10

[richardleach]

Thanks @andk.

I'm assuming that it's this test that fails (and the following one presumably would too).

cblock {
        AV * my_av = newAV();
        SvREFCNT_dec(my_av);
}
BEGIN { pass 'newAV does not cause croak' }

I'm not familiar with how cblocks work but will try to look into it. (Don't have much time right this minute though.)

The internal error comes from this code in lib/C/Blocks.xs:

OP * build_op(pTHX_ TCCState * state, int keyword_type) {
        /* build a null op if not creating a cblock */
        if (keyword_type != IS_CBLOCK) return newOP(OP_NULL, 0);
         
        /* get the function pointer for the block */
        IV pointer_IV = PTR2IV(tcc_get_symbol(state, "op_func"));
        if (pointer_IV == 0) {
                croak("C::Blocks internal error: got null pointer for op function!");
        }
         
        /* Store the address of the function pointer on the stack */
        OP * o = newUNOP(OP_RAND, 0, newSVOP(OP_CONST, 0, newSViv(pointer_IV)));
         
        /* Create an op that pops the address off the stack and invokes it */
        o->op_ppaddr = Perl_tcc_pp;
         
        return o;
}

My first guess is that since 75acd14 inlined newSV_type, this build_op function therefore can't find the symbol.

[richardleach]

@run4flat - is C::Blocks currently able to handle other inline functions somehow? Or can you see any way that it could?

[xenu]

To me it looks like a bug in TCC. It successfully compiles the function below (in execute_compiler) and then it complains it can't find the op_func symbol (in build_op).

void op_func(C_BLOCKS_THX_DECL) {
        AV * my_av = newAV();
        SvREFCNT_dec(my_av);
}

[rjbs]

I believe the general consensus is that this does not block the release of v5.36.0, and am marking it as such.

[run4flat]

I apologize for my silence on this. I haven't had time to work on C::Blocks for quite a while and don't anticipate yours tuits any time soon. It is highly experimental and issues with it should not block any Perl development. I hope this hasn't caused any slow down! David

…

On Sun, Apr 17, 2022, 9:25 AM Ricardo Signes ***@***.***> wrote: I believe the general consensus is that this does not block the release of v5.36.0, and am marking it as such. — Reply to this email directly, view it on GitHub <#19561 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAB7Q57FXPJ3N5DLBVDDPW3VFQGODANCNFSM5RQJLQ7A> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[richardleach]

@run4flat - it doesn't seem like this is a bug in perl (and the breaking change seems entirely legitimate), so I propose to close this issue. Would you like me to create an issue on C::Blocks' bugtracker at the same time?

[jkeenan]

@run4flat - it doesn't seem like this is a bug in perl (and the breaking change seems entirely legitimate), so I propose to close this issue. Would you like me to create an issue on C::Blocks' bugtracker at the same time?

+1 to your closing this ticket once you've opened a ticket in the bugtracker for C::Blocks.

[richardleach]

Closed now that a ticket exists in the C::Blocks bugtracker.