[trans-mem,darwin] PR/52042 find tm_clone_table with PIE
Iain Sandoe
developer@sandoe-acoustics.co.uk
Thu Feb 9 12:31:00 GMT 2012
Hi Patrick,
apologies for
(a) the extra loop - I missed a deprecation warning when I built your
last version ...
(b) rolling two things into one mail ...
... (point 1 is related the pie issue, point 2 to linkage hassles).
On 9 Feb 2012, at 08:36, Iain Sandoe wrote:
>>
>> I think refs (from libstdc++) should be satisfied at link time with
>> -lstdc++ but probably I am missing something?
>
> when you link c++ code, that is what is required .. but obv. we
> don't want lstdc++ on the link line for c (because the library
> *will* be found @ runtime - and thus the routines would be called).
>
> I have an idea ... perhaps we supply (yet another) crt that is
> linked last on the line and provides the dummies. That way the
> linkage will be satisfied from libstd++ for c++ and the dummies for c.
>
> will try and see if I can fit a trial of that idea in on D9 & D10.
Point 2 below... now I look at this again, I wonder why the current
scheme doesn't cause a problem for Rainer on c++ as well?
===
anyway.
1/ one of the routines you had in the fix was deprecated, can we try:
+ Dl_info info;
+
+ if (! dladdr (f, &info) || info.dli_fbase == NULL)
+ abort ();
+
+ mh = (struct mach_header *) info.dli_fbase;
(and the additional header include) instead?
2/ I've moved the dummy routines to the [Darwin] tm crt endfile ..
+/* Provide dummy functions to satisfy linkage for versions of the
Darwin tool-chain that
+ that can't handle undefined weak refs at the link stage. */
+
+extern void *__cxa_allocate_exception (size_t) WEAK;
+extern void __cxa_throw (void *, void *, void *) WEAK;
+extern void *__cxa_begin_catch (void *) WEAK;
+extern void *__cxa_end_catch (void) WEAK;
+extern void __cxa_tm_cleanup (void *, void *, unsigned int) WEAK;
+
+void *__cxa_allocate_exception (size_t s UNUSED) { return NULL; }
+void __cxa_throw (void * a UNUSED, void * b UNUSED, void * c UNUSED)
+{ return; }
+void *__cxa_begin_catch (void * a UNUSED) { return NULL; }
+void *__cxa_end_catch (void) { return NULL; }
+void __cxa_tm_cleanup (void * a UNUSED, void * b UNUSED, unsigned
int c UNUSED)
+{ return; }
+
Rainer, would that work for you too ? ... it would allow removal from
libitm/eh_cpp.cc
for now, for Darwin:
-#if !defined (HAVE_ELF_STYLE_WEAKREF)
+#if !defined (HAVE_ELF_STYLE_WEAKREF) && ! defined (__MACH__)
====
The attached works with/without -fpie on Darwin 9, I won't get a
chance to test on D10 for a while, that machine is fully tied up ...
and I don't have D11 .... could people try it, if this seems reasonable?
Iain
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: 184018-tm-tweaks.txt
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20120209/eaa29303/attachment.txt>
-------------- next part --------------
More information about the Gcc-patches
mailing list