Change #pragma inline_depth(8) to use empty () for default value.

1 files changed, 29 insertions, 8 deletions

diff --git a/ANNOUNCE b/ANNOUNCE
index 49db4c8..feeda29 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -151,6 +151,8 @@ As defined in the new POSIX standard, and the Single Unix Spec version 3:
 

 pthread.h no longer includes windows.h

 --------------------------------------

+[Not yet for G++]

+

 This was done to prevent conflicts.

 

 HANDLE, DWORD, and NULL are temporarily defined within pthread.h if

@@ -208,13 +210,19 @@ Known bugs in this snapshot
 

    Workaround [rpj - 2 Feb 2002]

    -----------------------------

-   The problem disappears when /Ob0 is used, i.e. /O2 /Ob0 works OK.

+   The problem disappears when /Ob0 is used, i.e. /O2 /Ob0 works OK,

+   but if you want to use inlining optimisation you can be much more

+   specific about where it's switched off and on by using a pragma.

 

    So the inlining optimisation is interfering with the way that cleanup

-   handlers are run. In order to confirm this, the following use of pragmas

-   gets around the problem but I don't know how to make it transparent, in say,

-   pthread.h where pthread_cleanup_push is a macro that expands (in the C++ case) to

-   a local object instantiation with handlerFunc as the destructor (see pthread.h):

+   handlers are run. It appears to relate to auto-inlining of class methods

+   since this is the only auto inlining that is performed at /O1 optimisation

+   (functions with the "inline" qualifier are also inlined, but the problem

+   doesn't appear to involve any such functions in the library or testsuite).

+

+   In order to confirm the inlining culprit, the following use of pragmas

+   eliminate the problem but I don't know how to make it transparent, putting

+   it in, say, pthread.h where pthread_cleanup_push defined as a macro.

 

    #pragma inline_depth(0)

      pthread_cleanup_push(handlerFunc, (void *) &arg);

@@ -222,13 +230,26 @@ Known bugs in this snapshot
         /* ... */

 

      pthread_cleanup_pop(0);

-   #pragma inline_depth(8)

+   #pragma inline_depth()

+

+   Note the empty () value after the pop macro. This resets depth to the

+   default. Or you can specify a non-zero depth here.

 

    The pragma is also needed (and now used) within the library itself wherever

    cleanup handlers are used (condvar.c and rwlock.c).

 

-   Use of these pragmas allows compiler optimisation /O2 to be used for

-   both the library and applications.

+   Use of these pragmas allows compiler optimisations /O1 and /O2 to be

+   used for either or both the library and applications.

+

+   Experimenting further, I found that wrapping the actual cleanup handler

+   function with #pragma auto_inline(off|on) does NOT work.

+

+   MSVC6.0 doesn't appear to support the C99 standard's _Pragma directive,

+   however, later versions may. This form is embeddable inside #define

+   macros, which would be ideal because it would mean that it could be added

+   to the push/pop macro definitions in pthread.h and hidden from the

+   application programmer.

+

    [/rpj]

 

    Original problem description