[Bug objc/43061] New: 47 new GCC HEAD@156527 regressions

[Bug objc/43061] New: 47 new GCC HEAD@156527 regressions

[dominiq at lps dot ens dot fr]

Between revisions156515 and 156527 many new failures have appeared in the objc
test suite (see http://gcc.gnu.org/ml/gcc-regression/2010-02/msg00013.html ).
These errors are still there at revision 156749 (see
http://gcc.gnu.org/ml/gcc-testresults/2010-02/msg01291.html or
http://gcc.gnu.org/ml/gcc-testresults/2010-02/msg01290.html ) and seem to need
'-On  -fnext-runtime' with n!=0.

Note that the errors do not appear on the Jack Howarth tests for
x86_64-apple-darwin10.3.0 (see
http://gcc.gnu.org/ml/gcc-testresults/2010-02/msg01258.html ) while they do on 
x86_64-apple-darwin10.2 (see
http://gcc.gnu.org/ml/gcc-testresults/2010-02/msg00747.html ).


-- 
           Summary: 47 new GCC HEAD@156527 regressions
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: objc
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dominiq at lps dot ens dot fr
 GCC build triplet: *-apple-darwin*
  GCC host triplet: *-apple-darwin*
GCC target triplet: *-apple-darwin*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #1 from developer at sandoe-acoustics dot co dot uk  2010-02-14 13:46 -------
confirmed, this can be reproduced outside the testsuite framework:
for example... [ppc/darwin9/156749];

$ ./gcc/xgcc -B gcc ../gcc-4-5-trunk/gcc/testsuite/objc/execute/cascading-1.m
-fnext-runtime -O1 -o tc -lobjc -g -save-temps

$ gdb tc
GNU gdb 6.3.50-20050815 (Apple version gdb-967) (Tue Jul 14 02:15:14 UTC 2009)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "powerpc-apple-darwin"...Reading symbols for shared
libraries ..... done

(gdb) run
Starting program: /Volumes/ScratchCS/gcc-4-5-trunk-build/tc 
Reading symbols for shared libraries +++... done

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x466f6f20
0x9622dfd8 in objc_msgSend ()
(gdb) backtrace
#0  0x9622dfd8 in objc_msgSend ()
#1  0x00001f8c in main (argc=<value temporarily unavailable, due to
optimizations>, argv=<value temporarily unavailable, due to optimizations>) at
../gcc-4-5-trunk/gcc/testsuite/objc/execute/cascading-1.m:33
(gdb) 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2010-02-14 15:25 -------
Track down the regression that caused this and see what actually is the
difference in generated code and/or tree/rtl dumps.  Access to non-free
operating systems is restricted.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #3 from developer at sandoe-acoustics dot co dot uk  2010-02-14 16:04 -------
(In reply to comment #2)
> Track down the regression that caused this

r156519

>and see what actually is the  difference in generated code and/or tree/rtl dumps. 

what output would be the most useful?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2010-02-14 16:28 -------
(In reply to comment #3)
> (In reply to comment #2)
> > Track down the regression that caused this
> 
> r156519
> 
> >and see what actually is the  difference in generated code and/or tree/rtl dumps. 
> 
> what output would be the most useful?

Make one directory for each revision for outputs from -fdump-tree-all,
tar them up and attach them.  A single testcase that passes before and
fails after the revision should be enough.  You can leave out dumps
that are identical for both revisions.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #6 from developer at sandoe-acoustics dot co dot uk  2010-02-14 16:33 -------
Created an attachment (id=19861)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19861&action=view)
optimized tree diffs.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #5 from developer at sandoe-acoustics dot co dot uk  2010-02-14 16:32 -------
Created an attachment (id=19860)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19860&action=view)
generated asm differences with/without r156519


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #7 from developer at sandoe-acoustics dot co dot uk  2010-02-14 16:45 -------
Created an attachment (id=19862)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19862&action=view)
diffs for all fdump-tree-all output


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2010-02-14 17:44 -------
Hm.  So CCP through get_symbol_constant_value causes

 <bb 2>:
-  _OBJC_CLASS_REFERENCES_0.2_1 = _OBJC_CLASS_REFERENCES_0;
+  _OBJC_CLASS_REFERENCES_0.2_1 = (struct objc_class *) &_OBJC_CLASS_NAME_0;
   _OBJC_CLASS_REFERENCES_0.3_2 = (struct objc_object *)
_OBJC_CLASS_REFERENCES_0.2_1;
-  _OBJC_SELECTOR_REFERENCES_0.4_3 = _OBJC_SELECTOR_REFERENCES_0;
+  _OBJC_SELECTOR_REFERENCES_0.4_3 = (struct objc_selector *)
&_OBJC_METH_VAR_NAME_1;
   D.3683_4 = OBJ_TYPE_REF(objc_msgSend;_OBJC_CLASS_REFERENCES_0.3_2->0)
(_OBJC_CLASS_REFERENCES_0.3_2, _OBJC_SELECTOR_REFERENCES_0.4_3);
-  _OBJC_SELECTOR_REFERENCES_1.5_5 = _OBJC_SELECTOR_REFERENCES_1;
+  _OBJC_SELECTOR_REFERENCES_1.5_5 = (struct objc_selector *)
&_OBJC_METH_VAR_NAME_0;
   OBJ_TYPE_REF(objc_msgSend;D.3683_4->0) (D.3683_4,
_OBJC_SELECTOR_REFERENCES_1.5_5);
   return 0;

which means that _OBJC_CLASS_REFERENCES_0 must be a TREE_READONLY static
with an initializer.  I wonder how exactly that tree looks like, so can
you run the compile inside gdb, break on get_symbol_constant_value
until you get _OBJC_CLASS_REFERENCES_0 as argument (may happen multiple
times) and paste the output of

(gdb) call debug_tree (sym)
(gdb) call debug_tree (sym->decl_common.initial)

?

Thanks.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #9 from developer at sandoe-acoustics dot co dot uk  2010-02-14 18:50 -------
(In reply to comment #8)
> Hm.  So CCP through get_symbol_constant_value causes

> you run the compile inside gdb, break on get_symbol_constant_value

maybe I've messed something up - but setting a break on
get_symbol_constant_value ..
.. the cc1obj just completes with "Program exited normally'.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2010-02-14 19:00 -------
(In reply to comment #9)
> (In reply to comment #8)
> > Hm.  So CCP through get_symbol_constant_value causes
> 
> > you run the compile inside gdb, break on get_symbol_constant_value
> 
> maybe I've messed something up - but setting a break on
> get_symbol_constant_value ..
> .. the cc1obj just completes with "Program exited normally'.

That can't be.  Make sure to enable optimization though.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #11 from rguenth at gcc dot gnu dot org  2010-02-14 19:01 -------
Btw, I cannot make -fnext-runtime work on i?86-linux, it errors at link time
with
undefined references.  Any configure options I need to supply?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[pinskia at gcc dot gnu dot org]

------- Comment #12 from pinskia at gcc dot gnu dot org  2010-02-14 19:07 -------
(In reply to comment #11)
> Btw, I cannot make -fnext-runtime work on i?86-linux, it errors at link time
> with
> undefined references.  Any configure options I need to supply?
> 

The next runtime only works on Darwin.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #13 from developer at sandoe-acoustics dot co dot uk  2010-02-14 21:13 -------
Created an attachment (id=19864)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19864&action=view)
gdb-output for CLASS_REFERENCES_0 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #14 from rguenth at gcc dot gnu dot org  2010-02-14 21:29 -------
That doesn't make sense.  The symbol is not TREE_READONLY.

Was that dump from inside get_symbol_constant_value?

As the extract only happens from CCP2 I suppose that ipa-reference might
be setting TREE_READONLY on the decl becaue it's static and not written to?
So, can you try with -fno-ipa-reference?  (-fdump-ipa-reference should
show "read-only var OBJC_CLASS_REFERENCES_0" if that is the problem)

Can it be that the next runtime causes functions to be emitted in the
back of cgraph?  Or maybe the objc frontend fails to set TREE_ADDRESSABLE
on those vars? Or it forgets to pass them to the varpool?

Can you attach the full ipa-reference dump and the full 004.gimple dump?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #15 from developer at sandoe-acoustics dot co dot uk  2010-02-14 21:53 -------
(In reply to comment #14)
> That doesn't make sense.  The symbol is not TREE_READONLY.
> 
> Was that dump from inside get_symbol_constant_value?

yes.
that was from a clean bootstrap of trunk 156760.

> As the extract only happens from CCP2 I suppose that ipa-reference might
> be setting TREE_READONLY on the decl becaue it's static and not written to?
> So, can you try with -fno-ipa-reference?  (-fdump-ipa-reference should
> show "read-only var OBJC_CLASS_REFERENCES_0" if that is the problem)

-fdump-ipa-reference - is unrecognized on my build - do I need a config. option
to enable?
-fdump-ipa-all doesn't seem to give a file named as reference...


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #16 from developer at sandoe-acoustics dot co dot uk  2010-02-14 21:55 -------
Created an attachment (id=19866)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19866&action=view)
gimple for cascading-1.m @ trunk 156760


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #17 from rguenth at gcc dot gnu dot org  2010-02-14 21:56 -------
(In reply to comment #15)
> (In reply to comment #14)
> > That doesn't make sense.  The symbol is not TREE_READONLY.
> > 
> > Was that dump from inside get_symbol_constant_value?
> 
> yes.
> that was from a clean bootstrap of trunk 156760.
> 
> > As the extract only happens from CCP2 I suppose that ipa-reference might
> > be setting TREE_READONLY on the decl becaue it's static and not written to?
> > So, can you try with -fno-ipa-reference?  (-fdump-ipa-reference should
> > show "read-only var OBJC_CLASS_REFERENCES_0" if that is the problem)
> 
> -fdump-ipa-reference - is unrecognized on my build - do I need a config. option
> to enable?
> -fdump-ipa-all doesn't seem to give a file named as reference...

Ah, sorry.  The dump file is called static-var.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #18 from developer at sandoe-acoustics dot co dot uk  2010-02-14 22:11 -------
Created an attachment (id=19867)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19867&action=view)
-fdump-ipa-all/static-var cascading-1.m @ trunk 156760

this is with normal options (i.e. the default for ipa-reference)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #19 from developer at sandoe-acoustics dot co dot uk  2010-02-14 22:16 -------
Created an attachment (id=19868)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19868&action=view)
cascading-1.m/-fdump-ipa-all/pure-const @ trunk 15670

this is with -fno-ipa-reference.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #20 from rguenth at gcc dot gnu dot org  2010-02-14 22:25 -------
Not TREE_ADDRESSABLE var _OBJC_CLASS_REFERENCES_0
Not TREE_ADDRESSABLE var _OBJC_SELECTOR_REFERENCES_0
Not TREE_ADDRESSABLE var _OBJC_SELECTOR_REFERENCES_1
read-only var _OBJC_CLASS_REFERENCES_0
read-only var _OBJC_SELECTOR_REFERENCES_0
read-only var _OBJC_SELECTOR_REFERENCES_1

So it's indeed ipa-reference that promotes the static vars and CCP that
propagates the initializer.  I see nothing wrong here, so the ObjC frontend
must do something behind the middle-ends back.

If you look at the final assembler code, is there anything modifying
the contents of those three variables?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #21 from developer at sandoe-acoustics dot co dot uk  2010-02-14 23:22 -------
Created an attachment (id=19870)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19870&action=view)
asm out from -O1 -g cascading-1.m @trunk 156760

this is the current asm output - it segfaults on the objc msg call.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #22 from rguenth at gcc dot gnu dot org  2010-02-14 23:26 -------
There are no modifications visible in the assembly.  But there is magic:

        .objc_cls_refs
        .align 2
L_OBJC_CLASS_REFERENCES_0:
        .long   L_OBJC_CLASS_NAME_0

what is .objc_cls_refs?

Well, obviously some Objective-C maintainer needs to chime in and explain
things.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #23 from developer at sandoe-acoustics dot co dot uk  2010-02-14 23:57 -------
(In reply to comment #22)
> There are no modifications visible in the assembly.  But there is magic:
> 
>         .objc_cls_refs
>         .align 2
> L_OBJC_CLASS_REFERENCES_0:
>         .long   L_OBJC_CLASS_NAME_0
> 
> what is .objc_cls_refs?

DEF_SECTION (objc_cls_refs_section, SECTION_MERGE, ".objc_cls_refs", 1)

If I've got this correct - this is implementing the constraint that class names
are global in the NeXT runtime [at least at release 0/1].  I assume that the
section merge arranges that all references to class FOO point to the same and
unique class definition. 

> > Well, obviously some Objective-C maintainer needs to chime in and explain
> things.

indeed.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[mikestump at comcast dot net]

------- Comment #24 from mikestump at comcast dot net  2010-02-15 17:38 -------
Yes, I think IainS is on the right track, all things in objc_cls_refs escape
and can be read and written to in unexpected ways by the runtime.  Setting
TREE_ADDRESSABLE sounds like a reasonable step forward.


-- 

mikestump at comcast dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mikestump at comcast dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #25 from developer at sandoe-acoustics dot co dot uk  2010-02-15 19:54 -------
Hm.  I tried this trivial patch:
Index: gcc/objc/objc-act.c
===================================================================
--- gcc/objc/objc-act.c (revision 156760)
+++ gcc/objc/objc-act.c (working copy)
@@ -2533,7 +2533,8 @@

   sprintf (buf, "_OBJC_SELECTOR_REFERENCES_%d", selector_reference_idx++);
   decl = start_var_decl (objc_selector_type, buf);
-
+  if (flag_next_runtime) 
+    TREE_ADDRESSABLE (decl) = 1;
   return decl;
 }

@@ -2733,6 +2734,8 @@

   sprintf (buf, "_OBJC_CLASS_REFERENCES_%d", class_reference_idx++);
   decl = start_var_decl (objc_class_type, buf);
+  if (flag_next_runtime) 
+    TREE_ADDRESSABLE (decl) = 1;

   return decl;
 }

and when I check in gdb the trees are marked as addressable [checking in
objc-act.c/finish_var_decl() ].
... but something is un-doing this later - and _OBJC_CLASS_REFERENCES_0 is
ending up marked as not tree addressable according to the ipa dump.

any ideas where I'm going wrong?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[jakub at gcc dot gnu dot org]

------- Comment #26 from jakub at gcc dot gnu dot org  2010-02-15 21:09 -------
Addressability is recomputed several times.  What you probably want is mark the
decl with the used attribute (i.e. add "used" attribute to it, set TREE_USED
(decl) = 1 and DECL_PRESERVE_P (decl) = 1).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #27 from developer at sandoe-acoustics dot co dot uk  2010-02-15 21:51 -------
(In reply to comment #26)
> Addressability is recomputed several times.  What you probably want is mark the
> decl with the used attribute (i.e. add "used" attribute to it, set TREE_USED
> (decl) = 1 and DECL_PRESERVE_P (decl) = 1).

finish_var_decl() contains:
mark_decl_referenced(var); - although this doesn't do anything for csts.
and
TREE_USED (var) = 1;

adding  DECL_PRESERVE_P (decl) = 1 doesn't solve the problem either..

I'll have to dig deeper into what's actually happening/required.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[jakub at gcc dot gnu dot org]

------- Comment #28 from jakub at gcc dot gnu dot org  2010-02-15 22:37 -------
    DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("used"), NULL,
DECL_ATTRIBUTES (decl));
is also needed (no idea why ipa*.c/cgraphunit.c use lookup_attribute instead of
testing DECL_PRESERVED_P, but they do).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #29 from developer at sandoe-acoustics dot co dot uk  2010-02-15 23:10 -------
Created an attachment (id=19884)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19884&action=view)
attach "used" attribute as well as marking vars used.

Jakub's comment seems to do the trick - thanks.
I've applied a "used" attribute in the same place that the TREE_USED is placed.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #30 from developer at sandoe-acoustics dot co dot uk  2010-02-16 09:23 -------
apropos 
http://gcc.gnu.org/ml/gcc-patches/2010-02/msg00587.html

do you think that _OBJC_CLASS_REFERENCES_* and _OBJC_SELECTOR_REFERENCES_*
should be marked as TREE_ADDRESSABLE and DECL_PRESERVE_P in anticipation that
this change (ipa* and cgraphunit responding to PRESERVE_P) will occur in the
future?

(I took those changes out of this patch on the grounds that they didn't
currently achieve anything).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[jakub at gcc dot gnu dot org]

------- Comment #31 from jakub at gcc dot gnu dot org  2010-02-16 10:06 -------
Not sure about TREE_ADDRESSABLE, but certainly DECL_PRESERVED_P should be set
as well.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #32 from rguenth at gcc dot gnu dot org  2010-02-16 10:14 -------
(In reply to comment #24)
> Yes, I think IainS is on the right track, all things in objc_cls_refs escape
> and can be read and written to in unexpected ways by the runtime.  Setting
> TREE_ADDRESSABLE sounds like a reasonable step forward.

Why are they marked TREE_READONLY then?  That sounds like the bug.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[rguenth at gcc dot gnu dot org]

------- Comment #33 from rguenth at gcc dot gnu dot org  2010-02-16 10:14 -------
(In reply to comment #32)
> (In reply to comment #24)
> > Yes, I think IainS is on the right track, all things in objc_cls_refs escape
> > and can be read and written to in unexpected ways by the runtime.  Setting
> > TREE_ADDRESSABLE sounds like a reasonable step forward.
> 
> Why are they marked TREE_READONLY then?  That sounds like the bug.

Err, forget that ;)  Still early today...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #34 from developer at sandoe-acoustics dot co dot uk  2010-02-16 14:58 -------
Created an attachment (id=19889)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19889&action=view)
patch with CLASS and SELECTOR refs. marked as TREE_ADDRESSABLE &
DECL_PRESERVE_P (for NeXT runtime)

In view of the comments in
http://gcc.gnu.org/ml/gcc-patches/2010-02/msg00597.html and
http://gcc.gnu.org/ml/gcc-patches/2010-02/msg00587.html it's clear that people
feel that the bug is actually in ipa* and cgraphunit.c.  

However, a grep of lookup_attribute ipa* etc. suggests that altering these has
possibly wide-reaching effects, which might not be welcome at this stage.

I've added back in the marking of CLASS_REFERENCES_* and SELECTOR_REFERENCES_*
as TREE_ADDRESSABLE and DECL_PRESERVE_P.  Of course, this doesn't solve the
problem unless the addition of the "used" attribute in finish_var_decl() is
left in place too (although that can be removed once the underlying problem is
resolved).

Would it be best to close this bug with the lookup_attribute fix - and open a
new bug for ipa*.c and cgraphunit.c to support DECL_PRESERVE_P and/or
TREE_USED? 

In fact, I'm a bit confused about what combination of flags is really needed. 
TREE_USED appears to match in intent with "used" attribute - which is placed on
the vars in objc-act.c/finish_var_decl().

DECL_PRESERVE_P presumably should only be used on the
CLASS_REFERENCES/SELECTOR_REFERENCES - and thus I've placed it local to those
two definitions.


-- 

developer at sandoe-acoustics dot co dot uk changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #19884|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[mikestump at comcast dot net]

------- Comment #35 from mikestump at comcast dot net  2010-02-16 16:25 -------
Ok to the last patch for now.  Feel free to file a bug about checking
DECL_PRESERVE_P and add a pointer to remove the setting of DECL_ATTRIBUTES from
the frontend, thanks.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[mikestump at comcast dot net]

------- Comment #36 from mikestump at comcast dot net  2010-02-18 22:06 -------
I've checked in a slightly updated fix in r156877.  Let us know if all the
regressions are fixed now.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #37 from developer at sandoe-acoustics dot co dot uk  2010-02-19 08:43 -------
(In reply to comment #36)
> I've checked in a slightly updated fix in r156877.  Let us know if all the
> regressions are fixed now.
i686/powerpc-darwin9 - YES, thanks.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[mrs at gcc dot gnu dot org]

------- Comment #38 from mrs at gcc dot gnu dot org  2010-02-19 19:06 -------
Subject: Bug 43061

Author: mrs
Date: Fri Feb 19 19:06:38 2010
New Revision: 156907

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=156907
Log:
        PR objc/43061
        * cgraphunit.c (process_function_and_variable_attributes): Check
        DECL_PRESERVE_P instead of looking up attribute "used".
        * ipa-pure-const.c (check_decl): Likewise.
        * ipa-reference.c (has_proper_scope_for_analysis): Likewise.
        * ipa-type-escape.c (has_proper_scope_for_analysis): Likewise.
        * config/sol2.c (solaris_insert_attributes): Set DECL_PRESERVE_P
        instead of attribute "used".
        * config/sol2-c.c (solaris_pragma_init): Likewise.
        (solaris_pragma_fini): Likewise.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cgraphunit.c
    trunk/gcc/config/sol2-c.c
    trunk/gcc/config/sol2.c
    trunk/gcc/ipa-pure-const.c
    trunk/gcc/ipa-reference.c
    trunk/gcc/ipa-type-escape.c
    trunk/gcc/objc/objc-act.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[mikestump at comcast dot net]

------- Comment #39 from mikestump at comcast dot net  2010-02-19 19:15 -------
I checked in the real back end change in r156907.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[developer at sandoe-acoustics dot co dot uk]

------- Comment #40 from developer at sandoe-acoustics dot co dot uk  2010-02-19 23:28 -------
(In reply to comment #39)
> I checked in the real back end change in r156907.
OK on i686/powerpc d9


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061

[Bug objc/43061] 47 new GCC HEAD@156527 regressions

[dominiq at lps dot ens dot fr]

------- Comment #41 from dominiq at lps dot ens dot fr  2010-02-21 12:46 -------
AFAICT this pr and the side effects have been fixed, hence closing. If someone
disagree, please reopen.
Thanks all for the work.


-- 

dominiq at lps dot ens dot fr changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43061