On Thu, May 28, 2015 at 5:05 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, May 28, 2015 at 4:54 PM, Sriraman Tallam <tmsriram@google.com> wrote:
>> On Thu, May 28, 2015 at 2:52 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, May 28, 2015 at 2:27 PM, Sriraman Tallam <tmsriram@google.com> wrote:
>>>> On Thu, May 28, 2015 at 2:01 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>> On Thu, May 28, 2015 at 1:54 PM, Sriraman Tallam <tmsriram@google.com> wrote:
>>>>>> On Thu, May 28, 2015 at 12:05 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>>> On Thu, May 28, 2015 at 11:50 AM, Sriraman Tallam <tmsriram@google.com> wrote:
>>>>>>>> On Thu, May 28, 2015 at 11:42 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>>>>> On Thu, May 28, 2015 at 11:34 AM, Sriraman Tallam <tmsriram@google.com> wrote:
>>>>>>>>>> I have attached a patch that adds the new attribute "noplt".  Please review.
>>>>>>>>>>
>>>>>>>>>> * config/i386/i386.c (avoid_plt_to_call): New function.
>>>>>>>>>> (ix86_output_call_insn): Generate indirect call for functions
>>>>>>>>>> marked with "noplt" attribute.
>>>>>>>>>> (attribute_spec ix86_attribute_): Define new attribute "noplt".
>>>>>>>>>> * doc/extend.texi: Document new attribute "noplt".
>>>>>>>>>> * gcc.target/i386/noplt-1.c: New testcase.
>>>>>>>>>> * gcc.target/i386/noplt-2.c: New testcase.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 2 comments:
>>>>>>>>>
>>>>>>>>> 1. Don't remove "%!" prefix before call/jmp.  It is needed for MPX.
>>>>>>>>> 2. Don't you need to check
>>>>>>>>>
>>>>>>>>>       && !TARGET_MACHO
>>>>>>>>>       && !TARGET_SEH
>>>>>>>>>       && !TARGET_PECOFF
>>>>>>>>>
>>>>>>>>> since it only works for ELF.
>>>>>>>>
>>>>>>>> Ok, I will make this change. OTOH, is it just better to piggy-back on
>>>>>>>> existing -fno-plt change by Alex in calls.c
>>>>>>>> and do this:
>>>>>>>>
>>>>>>>> Index: calls.c
>>>>>>>> ===================================================================
>>>>>>>> --- calls.c (revision 223720)
>>>>>>>> +++ calls.c (working copy)
>>>>>>>> @@ -226,9 +226,11 @@ prepare_call_address (tree fndecl_or_type, rtx fun
>>>>>>>>         && targetm.small_register_classes_for_mode_p (FUNCTION_MODE))
>>>>>>>>        ? force_not_mem (memory_address (FUNCTION_MODE, funexp))
>>>>>>>>        : memory_address (FUNCTION_MODE, funexp));
>>>>>>>> -  else if (flag_pic && !flag_plt && fndecl_or_type
>>>>>>>> +  else if (fndecl_or_type
>>>>>>>>     && TREE_CODE (fndecl_or_type) == FUNCTION_DECL
>>>>>>>> -   && !targetm.binds_local_p (fndecl_or_type))
>>>>>>>> +   && !targetm.binds_local_p (fndecl_or_type)
>>>>>>>> +   && ((flag_pic && !flag_plt)
>>>>>>>> +       || (lookup_attribute ("noplt", DECL_ATTRIBUTES(fndecl_or_type)))))
>>>>>>>>      {
>>>>>>>>        funexp = force_reg (Pmode, funexp);
>>>>>>>>      }
>>>>>>>>
>>>>>>>
>>>>>>> Does it work on non-PIC calls?
>>>>>>
>>>>>> You are right, it doesnt work.  I have attached the patch with the
>>>>>> changes you mentioned.
>>>>>>
>>>>>
>>>>> Since direct_p is true, do wee need
>>>>>
>>>>> +  if (GET_CODE (call_op) != SYMBOL_REF
>>>>> +      || SYMBOL_REF_LOCAL_P (call_op))
>>>>> +    return false;
>>>>
>>>> We do need it right because  for this case below, I do not want an
>>>> indirect call:
>>>>
>>>> __attribute__((noplt))
>>>> int foo() {
>>>>   return 0;
>>>> }
>>>>
>>>> int main()
>>>> {
>>>>   return foo();
>>>> }
>>>>
>>>> Assuming foo is not inlined, if I remove the lines you mentioned, I
>>>> will get an indirect call which is unnecessary.
>>>>
>>>
>>> I meant the "GET_CODE (call_op) != SYMBOL_REF" part isn't
>>> needed.
>>
>> I should have realized that :), sorry.  Patch fixed.
>>
>
> --- testsuite/gcc.target/i386/noplt-1.c (revision 0)
> +++ testsuite/gcc.target/i386/noplt-1.c (working copy)
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target x86_64-*-* } } */
> ...
> +/* { dg-final { scan-assembler "call\[
> \t\]\\*.*foo.*@GOTPCREL\\(%rip\\)" } } */
>
> The test will fail on Windows and Darwin.

Changed to use x86_64-*-linux* target.

>
>
> --
> H.J.