[RFA/GC] redefine thread suspension interface for all platforms

[Keith Seitz]

[pardon the top post]

Ping.

If anyone has a system other than x86 linux, powerpc darwin, or x86 
cygwin an can test this patch (it doesn't take much time to rebuild 
boehm-gc and libjava), I would be very, very grateful...

Keith


Keith Seitz wrote:
> Hi,
> 
> After last week's build debacle, I've decided to "do it right", or at
> least what I think is right. I should know better than to resort to
> conditionally including code.
> 
> Therefore, I would like to redefine the current suspension interface
> from this mess:
> 
> #if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
>   && !defined(GC_WIN32_THREADS) && !defined(GC_DARWIN_THREADS)
> GC_API void GC_suspend_thread GC_PROTO((pthread_t));
> GC_API void GC_resume_thread GC_PROTO((pthread_t));
> #endif
> 
> to the more readable/maintainable:
> 
> GC_API void GC_suspend_thread GC_PROTO((GC_thread_t));
> GC_API void GC_resume_thread GC_PROTO((GC_thread_t));
> 
> Where GC_thread_t is defined appropriately for every platform. On
> platforms where the functions are unimplemented (anything but posix
> threads right now), the functions will call ABORT with an appropriate
> message.
> 
> There are lots of different ways to do this, but I find this the least 
> offensive of the solutions I've pondered. There seems little sense in 
> submitting this to the GC list since no decision has been officially 
> made on the existence of GC_suspend/resume_thread yet.
> 
> I have tested this on x86 linux, powerpc-darwin, and x86 cygwin. 
> Nonetheless, the giant ifdef in gc.h will, I'm sure, not be complete (or 
> necessarily correct). I would appreciate it if those-in-the-know would 
> pay special attention to this.
> 
> Keith
> 
> ChangeLog
> 2006-07-06  Keith Seitz  <keiths@redhat.com>
> 
>     * include/gc.h (GC_thread_t): Define.
>     (GC_suspend_thread): Define for all platforms.
>     (GC_resume_thread): Likewise.
>     * darwin_stop_world.c (GC_suspend_thread): New function.
>     (GC_resume_thread): New function.
>     * pthread_stop_world.c (GC_suspend_thread): New function.
>     (GC_resume_thread): New function.
>     * solaris_threads.c (GC_suspend_thread): New function.
>     (GC_resume_thread): New function.
>     * win32_threads.c (GC_suspend_thread): New function.
>     (GC_resume_thread): New function.
> 
> 
> 
> ------------------------------------------------------------------------
> 
> Index: include/gc.h
> ===================================================================
> --- include/gc.h	(revision 115072)
> +++ include/gc.h	(working copy)
> @@ -1036,18 +1036,35 @@
>  #  include  "gc_local_alloc.h"
>  #endif
>  
> +      /* External thread suspension support. These functions do not
> +       * implement suspension counts or any other higher-level abstraction.
> +       * Threads which have been suspended numerous times will resume with
> +       * the very first call to GC_resume_thread.
> +       */
> +#if defined(GC_DARWIN_THREADS)
> +      typedef thread_act_t GC_thread_t;
> +#elif defined(GC_SOLARIS_PTHREADS)
> +      typedef pthread_t GC_thread_t;
> +#elif defined(GC_SOLARIS_THREADS)
> +      typedef thread_t GC_thread_t;
> +#elif defined(GC_WIN32_THREADS)
> +#     ifdef __CYGWIN32__
> +         typedef pthread_t GC_thread_t;
> +#     else
> +         typedef DWORD GC_thread_t;      
> +#     endif
> +#else
> +#     ifdef __CYGWIN32__
> +#       include <pthread.h>
> +#     endif
> +      typedef pthread_t GC_thread_t;
> +#endif
> +
> +      GC_API void GC_suspend_thread GC_PROTO((GC_thread_t));
> +      GC_API void GC_resume_thread GC_PROTO((GC_thread_t));
> +
>  #ifdef __cplusplus
>      }  /* end of extern "C" */
>  #endif
>  
> -/* External thread suspension support. These functions do not implement
> - * suspension counts or any other higher-level abstraction. Threads which
> - * have been suspended numerous times will resume with the very first call
> - * to GC_resume_thread.
> - */
> -#if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
> -  && !defined(GC_WIN32_THREADS) && !defined(GC_DARWIN_THREADS)
> -GC_API void GC_suspend_thread GC_PROTO((pthread_t));
> -GC_API void GC_resume_thread GC_PROTO((pthread_t));
> -#endif
>  #endif /* _GC_H */
> Index: darwin_stop_world.c
> ===================================================================
> --- darwin_stop_world.c	(revision 115072)
> +++ darwin_stop_world.c	(working copy)
> @@ -503,4 +503,11 @@
>    GC_use_mach_handler_thread = 1;
>  }
>  
> +void GC_suspend_thread(GC_thread_t thread) {
> +  ABORT("GC_suspend_thread not implemented");
> +}
> +
> +void GC_resume_thread(GC_thread_t thread) {
> +  ABORT("GC_resume_thread not implemented");
> +}
>  #endif
> Index: pthread_stop_world.c
> ===================================================================
> --- pthread_stop_world.c	(revision 115072)
> +++ pthread_stop_world.c	(working copy)
> @@ -454,7 +454,8 @@
>    GC_end_blocking();
>  }
>  
> -void GC_suspend_thread(pthread_t thread) {
> +void GC_suspend_thread(GC_thread_t thr) {
> +  pthread_t thread = (pthread_t) thr;
>    if (thread == pthread_self())
>      suspend_self();
>    else {
> @@ -475,8 +476,8 @@
>    }
>  }
>  
> -void GC_resume_thread(pthread_t thread) {
> -  GC_thread t = GC_lookup_thread(thread);
> +void GC_resume_thread(GC_thread_t thread) {
> +  GC_thread t = GC_lookup_thread((pthread_t) thread);
>    if (t == NULL)
>      ABORT("attempting to resume unknown thread");
>  
> Index: solaris_threads.c
> ===================================================================
> --- solaris_threads.c	(revision 115072)
> +++ solaris_threads.c	(working copy)
> @@ -951,6 +951,14 @@
>      return(result);
>  }
>  
> +void GC_suspend_thread(GC_thread_t thread) {
> +  ABORT("GC_suspend_thread not implemented");
> +}
> +
> +void GC_resume_thread(GC_thread_t thread) {
> +  ABORT("GC_resume_thread not implemented");
> +}
> +
>  # else /* !GC_SOLARIS_THREADS */
>  
>  #ifndef LINT
> Index: win32_threads.c
> ===================================================================
> --- win32_threads.c	(revision 115072)
> +++ win32_threads.c	(working copy)
> @@ -522,6 +522,14 @@
>  
>  #endif /* !CYGWIN32 */
>  
> +void GC_suspend_thread(GC_thread_t thread) {
> +  ABORT("GC_suspend_thread not implemented");
> +}
> +
> +void GC_resume_thread(GC_thread_t thread) {
> +  ABORT("GC_resume_thread not implemented");
> +}
> +
>  #ifdef MSWINCE
>  
>  typedef struct {