Re: [PATCH][Middle-end][Version 2]Add a new option to control inlining only on static functions

[Qing Zhao <qing dot zhao at oracle dot com>]

> On Sep 14, 2018, at 3:45 PM, Andrew Pinski <pinskia@gmail.com> wrote:
> 
> On Fri, Sep 14, 2018 at 1:42 PM Andrew Pinski <pinskia@gmail.com <mailto:pinskia@gmail.com>> wrote:
>> 
>> On Fri, Sep 14, 2018 at 1:34 PM Qing Zhao <qing.zhao@oracle.com> wrote:
>>> 
>>> Hi,
>>> 
>>> this is the 2nd version of the patch to add a new first-class option
>>> 
>>> -finline-only-static
>>> 
>>> to guide inlining only on static functions.
>>> 
>>> -finline-only-static
>>>  By default, GCC inlines functions without considering whether they are static
>>>  or not. This flag guides inliner to only inline static functions.
>>> 
>>>  Off by default.
>>> 
>>> The major purpose of this option is to provide a way for the user to disable inlining of global functions.
>>> this is mainly to help online patching users to control the memory consumption and ease the debugging.
>>> 
>>> please take a look and let me know any comments and suggestions:
>> 
>> How does this interact with -finline-functions?  Or rather isn't this
>> just the opposite of -finline-functions?
> 
> Seems to me, that this new option should just disable
> -finline-small-functions and -finline-functions.
> That is it is an alias with -fno-inline-small-functions -fno-inline-functions.

NO,  this option is NOT to disable -finline-small-funcitons and -finline-functions. 

when it’s specified, -finline-small-function and -finline-functions will ONLY inline static functions, all global functions will be disabled to 
be inlined.

Qing

> 
> My question comes up if someone uses -finline-functions
> -finline-only-static; or -finline-only-static -finline-functions.
> That it is a rather interesting combition of options but the
> interaction of the two options are not documented and seems backwards.
> 
> Thanks,
> Andrew Pinski
> 
>> 
>> Thanks,
>> Andrew
>> 
>>> 
>>> thanks a lot.
>>> 
>>> Qing
>>> 
>>> gcc/ChangeLog
>>> 
>>> +2018-09-13  Qing Zhao  <qing.zhao@oracle.com>
>>> +
>>> +       * cif-code.def (FUNCTION_EXTERN): New CIFCODE.
>>> +       * common.opt (-finline-only-static): New option.
>>> +       * doc/invoke.texi: Document -finline-only-static.
>>> +       * ipa-inline.c (can_inline_edge_p): Control inlining based on
>>> +       function's visibility.
>>> 
>>> gcc/testsuite/ChangeLog
>>> 
>>> +2018-09-13  Qing Zhao  <qing.zhao@oracle.com>
>>> +
>>> +       * gcc.dg/inline_only_static.c: New test.
>>> +
>>> 
>>> 
>>> 
>>>> On Sep 11, 2018, at 10:12 AM, Qing Zhao <qing.zhao@oracle.com> wrote:
>>>> 
>>>> Hi,
>>>> 
>>>> This is a simple patch to add a new first-class option
>>>> 
>>>> -finline-visibility={all|extern|static}
>>>> 
>>>> to finer control inlining based on function’s visibility.
>>>> 
>>>> '-finline-visibility=[all|extern|static]'
>>>>    By default, GCC inlines functions without considering their
>>>>    visibility.  This flag allows finer control of inlining based on
>>>>    their visibility.
>>>> 
>>>>    The value 'extern' tells the compiler to only inline functions with
>>>>    external visibility.  The value 'static' tells the compiler to only
>>>>    inline functions with static visibility.  The value 'all' tells the
>>>>    compilers to inline functions without considering their visibility.
>>>> 
>>>>    The default value of '-finline-visibility' is 'all'.
>>>> 
>>>> The major purpose of this option is to provide a way for the user
>>>> to finer choose the inline candidates based on function’s visibility.
>>>> For example, some online patching users might want to limit the inlining
>>>> to only static functions to avoid patching the callers of global functions
>>>> in order to control the memory consumption caused by online patching.
>>>> 
>>>> let me know any comments and suggestions.
>>>> 
>>>> thanks.
>>>> 
>>>> Qing