From 3ef98898333255b8000e9ab4801652c42fd5aacc Mon Sep 17 00:00:00 2001
From: rpj <rpj>
Date: Mon, 25 Apr 2005 14:42:37 +0000
Subject: ''
---
BUGS | 214 +++++++++++++++++++++++++++++++++----------------------------------
1 file changed, 107 insertions(+), 107 deletions(-)
(limited to 'BUGS')
diff --git a/BUGS b/BUGS
index d3a7b30..839b8ab 100644
--- a/BUGS
+++ b/BUGS
@@ -1,114 +1,114 @@
-----------
-Known bugs
-----------
-
-1. Not strictly a bug, more of a gotcha.
-
- Under MS VC++ (only tested with version 6.0), a term_func
- set via the standard C++ set_terminate() function causes the
- application to abort.
-
- Notes from the MSVC++ manual:
- 1) A term_func() should call exit(), otherwise
- abort() will be called on return to the caller.
- A call to abort() raises SIGABRT and the default signal handler
- for all signals terminates the calling program with
- exit code 3.
- 2) A term_func() must not throw an exception. Therefore
- term_func() should not call pthread_exit(), which
- works by throwing an exception (pthreadVCE or pthreadVSE)
- or by calling longjmp (pthreadVC).
-
- Workaround: avoid using pthread_exit() in C++ applications. Exit
- threads by dropping through the end of the thread routine.
-
-2. Cancellation problems in optimised code
- - Milan Gardian
-
+----------
+Known bugs
+----------
+
+1. Not strictly a bug, more of a gotcha.
+
+ Under MS VC++ (only tested with version 6.0), a term_func
+ set via the standard C++ set_terminate() function causes the
+ application to abort.
+
+ Notes from the MSVC++ manual:
+ 1) A term_func() should call exit(), otherwise
+ abort() will be called on return to the caller.
+ A call to abort() raises SIGABRT and the default signal handler
+ for all signals terminates the calling program with
+ exit code 3.
+ 2) A term_func() must not throw an exception. Therefore
+ term_func() should not call pthread_exit(), which
+ works by throwing an exception (pthreadVCE or pthreadVSE)
+ or by calling longjmp (pthreadVC).
+
+ Workaround: avoid using pthread_exit() in C++ applications. Exit
+ threads by dropping through the end of the thread routine.
+
+2. Cancellation problems in optimised code
+ - Milan Gardian
+
This is suspected to be a compiler bug in VC6.0, and also seen in
VC7.0 and VS .NET 2003. The GNU C++ compiler does not have a problem
with this, and it has been reported that the Intel C++ 8.1 compiler
and Visual C++ 2005 Express Edition Beta2 pass tests\semaphore4.c
(which exposes the bug).
- Workaround [rpj - 2 Feb 2002]
- -----------------------------
- [Please note: this workaround did not solve a similar problem in
- snapshot-2004-11-03 or later, even though similar symptoms were seen.
- tests\semaphore4.c fails in that snapshot for the VCE version of the
+ Workaround [rpj - 2 Feb 2002]
+ -----------------------------
+ [Please note: this workaround did not solve a similar problem in
+ snapshot-2004-11-03 or later, even though similar symptoms were seen.
+ tests\semaphore4.c fails in that snapshot for the VCE version of the
DLL.]
-
- 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. 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);
-
- /* ... */
-
- pthread_cleanup_pop(0);
- #pragma inline_depth()
-
- Note the empty () pragma 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 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
- ----------------------------
-
- The cancellation (actually, cleanup-after-cancel) tests fail when using VC
- (professional) optimisation switches (/O1 or /O2) in pthreads library. I
- have not investigated which concrete optimisation technique causes this
- problem (/Og, /Oi, /Ot, /Oy, /Ob1, /Gs, /Gf, /Gy, etc.), but here is a
- summary of builds and corresponding failures:
-
- * pthreads VSE (optimised tests): OK
- * pthreads VCE (optimised tests): Failed "cleanup1" test (runtime)
-
- * pthreads VSE (DLL in CRT, optimised tests): OK
- * pthreads VCE (DLL in CRT, optimised tests): Failed "cleanup1" test
- (runtime)
-
- Please note that while in VSE version of the pthreads library the
- optimisation does not really have any impact on the tests (they pass OK), in
- VCE version addition of optimisation (/O2 in this case) causes the tests to
- fail uniformly - either in "cleanup0" or "cleanup1" test cases.
-
- Please note that all the tests above use default pthreads DLL (no
- optimisations, linked with either static or DLL CRT, based on test type).
- Therefore the problem lies not within the pthreads DLL but within the
- compiled client code (the application using pthreads -> involvement of
- "pthread.h").
-
- I think the message of this section is that usage of VCE version of pthreads
- in applications relying on cancellation/cleanup AND using optimisations for
- creation of production code is highly unreliable for the current version of
- the pthreads library.
-
+
+ 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. 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);
+
+ /* ... */
+
+ pthread_cleanup_pop(0);
+ #pragma inline_depth()
+
+ Note the empty () pragma 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 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
+ ----------------------------
+
+ The cancellation (actually, cleanup-after-cancel) tests fail when using VC
+ (professional) optimisation switches (/O1 or /O2) in pthreads library. I
+ have not investigated which concrete optimisation technique causes this
+ problem (/Og, /Oi, /Ot, /Oy, /Ob1, /Gs, /Gf, /Gy, etc.), but here is a
+ summary of builds and corresponding failures:
+
+ * pthreads VSE (optimised tests): OK
+ * pthreads VCE (optimised tests): Failed "cleanup1" test (runtime)
+
+ * pthreads VSE (DLL in CRT, optimised tests): OK
+ * pthreads VCE (DLL in CRT, optimised tests): Failed "cleanup1" test
+ (runtime)
+
+ Please note that while in VSE version of the pthreads library the
+ optimisation does not really have any impact on the tests (they pass OK), in
+ VCE version addition of optimisation (/O2 in this case) causes the tests to
+ fail uniformly - either in "cleanup0" or "cleanup1" test cases.
+
+ Please note that all the tests above use default pthreads DLL (no
+ optimisations, linked with either static or DLL CRT, based on test type).
+ Therefore the problem lies not within the pthreads DLL but within the
+ compiled client code (the application using pthreads -> involvement of
+ "pthread.h").
+
+ I think the message of this section is that usage of VCE version of pthreads
+ in applications relying on cancellation/cleanup AND using optimisations for
+ creation of production code is highly unreliable for the current version of
+ the pthreads library.
+
--
cgit v1.2.3