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Re: Fix PR43404, PR48470, PR64744 ICE on naked functions


On 06/29/2015 07:32 AM, Alexander Basov wrote:
I've updated patch with attributes lookup.
is it OK?

-- Alexander 2015-06-26 9:33 GMT+03:00 Alexander Basov <coopht@gmail.com>:
>2015-06-25 21:47 GMT+03:00 Jeff Law<law@redhat.com>:
>>On 06/03/2015 02:15 PM, Alexander Basov wrote:
>>>
>>>Hello Jeff,
>>>please find updated patch attached
>>>
>>>>>diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
>>>>>index b190f91..c6db8a9 100644
>>>>>--- a/gcc/cfgexpand.c
>>>>>+++ b/gcc/cfgexpand.c
>>>>>@@ -1382,7 +1382,15 @@ expand_one_var (tree var, bool toplevel, bool
>>>>>really_expand)
>>>>>      else
>>>>>        {
>>>>>          if (really_expand)
>>>>>-        expand_one_stack_var (origvar);
>>>>>+        {
>>>>>+          if (!targetm.calls.allocate_stack_slots_for_args ())
>>>>>+            error ("cannot allocate stack for variable %q+D, naked
>>>>>function.",
>>>>>+                   var);
>>>>>+
>>>>>+          expand_one_stack_var (origvar);
>>>>>+        }
>>>>
>>>>So how do you know ORIGVAR is an argument here before issuing the
>>>>error?  ie, shouldn't you verify that the underlying object is a
>>>>PARM_DECL? If there's some way we already know we're dealing with a
>>>>PARM_DECL, then just say so.
>>>
>>>In case of naked function stack should not be used not only for function
>>>args, but also for any local variables.
>>>So, i think we don't need to check if underlying object is a PARM_DECL.
>>
>>Then that would indicate that we're using the wrong test
>>(allocate_stack_slot_for_args).  That hook is for whether or not arguments
>>should have stack slots allocated.  Yet you're issuing an error for more
>>than just PARM_DECLs.
>>
>>Shouldn't you instead be checking if the current function is a naked
>>function or not by checking the attributes of the current function?
>>
>>Jeff
>
>What allocate_stack_slots_for_args  does, it only checks if current
>function is naked or not.
>May be it will be better to remove allocate_stack_slots_for_args and
>replace if with explicit checking of naked attribute?
>
>--
>Alexander

pr64744.patch


commit 3a72dac72beb713ab6a566728b77c4da6d297755
Author: Alexander Basov<coohpt@gmail.com>
Date:   Tue Mar 10 14:15:24 2015 +0300

     	PR middle-end/64744
     	PR middle-end/48470
     	PR middle-end/43404

     	* gcc/cfgexpand.c (expand_one_var): Add check if stack is going to
     	be used in naked function.
     	* gcc/expr.c (expand_expr_addr_expr_1): Remove exscess checking
     	whether expression should not reside in MEM.
         * gcc/function.c (use_register_for_decl): Do not use registers for
     	non-register things (volatile, float, BLKMode) in naked functions.

     	* gcc/testsuite/gcc.target/arm/pr43404.c : New testcase.
     	* gcc/testsuite/gcc.target/arm/pr48470.c : New testcase.
     	* gcc/testsuite/gcc.target/arm/pr64744-1.c : New testcase.
         * gcc/testsuite/gcc.target/arm/pr64744-2.c : New testcase.
Sorry for the long delay. I've fixed up minor nits in the ChangeLog and committed your fixes.

Thanks,
jeff


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