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Re: [PATCH] Define GEN_AS_CONST_HEADERS when generating header files [BZ #22792]

On 02/21/2018 06:19 PM, H.J. Lu wrote:
On Wed, Feb 21, 2018 at 7:40 AM, H.J. Lu <> wrote:
On Tue, Feb 20, 2018 at 11:09 PM, Florian Weimer <> wrote:
On 02/08/2018 06:58 PM, H.J. Lu wrote:

         [BZ #22792]
         * Makerules ($(common-objpfx)%.h): Pass -DGEN_AS_CONST_HEADERS
         to $(CC).
         * sysdeps/unix/sysv/linux/i386/lowlevellock.h: Include
         <tcb-offsets.h> only if GEN_AS_CONST_HEADERS isn't defined.
         * sysdeps/unix/sysv/linux/x86_64/lowlevellock.h: Don't include

It looks to me that a cleaner fix would be to move the definition of the TCB
types to a separate header.

I will take a look.

sysdeps/i386/nptl/tcb-offsets.sym has

#include <sysdep.h>
#include <tls.h>
#include <kernel-features.h>

RESULT offsetof (struct pthread, result)
TID offsetof (struct pthread, tid)
CANCELHANDLING offsetof (struct pthread, cancelhandling)
CLEANUP_JMP_BUF offsetof (struct pthread, cleanup_jmp_buf)
MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
SYSINFO_OFFSET offsetof (tcbhead_t, sysinfo)
CLEANUP offsetof (struct pthread, cleanup)
CLEANUP_PREV offsetof (struct _pthread_cleanup_buffer, __prev)
MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
PRIVATE_FUTEX offsetof (tcbhead_t, private_futex)

It covers more than just tcbhead_t.  A separate header file for tcbhead_t
won't help here.

Yes, it's more involved.

The circular dependency is just a cosmetic warning from make, right?

It depends on how unlucky you are.  In one case on a many-core machine
with make -j60, I had to kill glibc build since it never stopped.

If it fixes an actual build issue, then I think your patch is acceptable, although I consider it quite hackish.

But please do add a comment explaining the issue before:



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