Re: [PATCH]Come up with -flive-patching master option.

[Jan Hubicka <hubicka@ucw.cz>]

> On 11/16/18 2:36 AM, Qing Zhao wrote:
> > Hi,
> > 
> > this is the new version of the patch.
> > 
> > I have bootstrapped it on both aarch64 and x86,  no regression.
> > 
> > please take a look.
> 
> Thanks for the updated version of the patch.
> I have last small nits I see:
> 
> - gcc/common.opt: when running --help=common, the line is too long
> - gcc/doc/invoke.texi - 2 spaces in between sentences + better gol
> - gcc/opts.c - do not mix spaces + tabs
> 
> With that I'm fine. But note that I'm not a maintainer :)

I wonder what happens, when I pass like -flive-patching -fwhole-program
compared to -fwhole-program -flive-patching.
It seems to me that in first case we will end up with whole-program
optimization while in the second we won't.

I guess we should behave in a way that we disable the passes when
they are enabled implicitly (such as by -O2) but output an error when
once uses contradicting set of options, lie -flive-patching
-fwhole-program?

Honza
> 
> Thanks,
> Martin
> 
> > 
> > Okay for commit?
> > 
> > thanks.
> > 
> > Qing
> > 
> > ==================================
> > 
> > gcc/ChangeLog:
> > 
> > 2018-11-15  qing zhao  <qing.zhao@oracle.com>
> > 
> > 	* cif-code.def (EXTERN_LIVE_ONLY_STATIC): New CIF code.
> > 	* common.opt: Add -flive-patching flag.
> > 	* doc/invoke.texi: Document -flive-patching.
> > 	* flag-types.h (enum live_patching_level): New enum.
> > 	* ipa-inline.c (can_inline_edge_p): Disable external functions from
> > 	inlining when flag_live_patching is LIVE_PATCHING_INLINE_ONLY_STATIC.
> > 	* opts.c (control_optimizations_for_live_patching): New function.
> > 	(finish_options): Make flag_live_patching incompatible with flag_lto.
> > 	(common_handle_option): Handle flive-patching flag.
> > 
> > gcc/testsuite/ChangeLog:
> > 
> > 2018-11-15  qing zhao  <qing.zhao@oracle.com>
> > 
> > 	* gcc.dg/live-patching-1.c: New test.
> > 	* gcc.dg/live-patching-2.c: New test.
> > 	* gcc.dg/tree-ssa/writeonly-3.c: New test.
> > 	* gcc.target/i386/ipa-stack-alignment-2.c: New test.
> > 

> From e44d8b88ac5fb712d5b5e7fdf2f2ad7f43b8ea09 Mon Sep 17 00:00:00 2001
> From: marxin <mliska@suse.cz>
> Date: Fri, 16 Nov 2018 16:23:44 +0100
> Subject: [PATCH] my fixes.
> 
> ---
>  gcc/common.opt      | 3 +--
>  gcc/doc/invoke.texi | 8 ++++----
>  gcc/opts.c          | 2 +-
>  3 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 63cd6cc851d..35c24b8e8cf 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -2187,8 +2187,7 @@ Common RejectNegative Alias(flive-patching=,inline-clone) Optimization
>  flive-patching=
>  Common Report Joined RejectNegative Enum(live_patching_level) Var(flag_live_patching) Init(LIVE_PATCHING_NONE) Optimization
>  -flive-patching=[inline-only-static|inline-clone]	Control IPA
> -optimizations to provide a safe compilation for live-patching. At the same
> -time, provides multiple-level control on the enabled IPA optimizations.
> +optimizations to provide a safe compilation for live-patching.
>  
>  Enum
>  Name(live_patching_level) Type(enum live_patching_level) UnknownError(unknown Live-Patching Level %qs)
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 0fb67163490..9cccc4455fa 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -9288,13 +9288,13 @@ impacted function of the former.  If a function is patched, its impacted
>  functions should be patched too.
>  
>  The impacted functions are decided by the compiler's interprocedural
> -optimizations. For example, inlining a function into its caller, cloning
> +optimizations.  For example, inlining a function into its caller, cloning
>  a function and changing its caller to call this new clone, or extracting
>  a function's pureness/constness information to optimize its direct or
>  indirect callers, etc.
>  
>  Usually, the more IPA optimizations enabled, the larger the number of
> -impacted functions for each function. In order to control the number of
> +impacted functions for each function.  In order to control the number of
>  impacted functions and computed the list of impacted function easily,
>  we provide control to partially enable IPA optimizations on two different
>  levels.
> @@ -9313,8 +9313,8 @@ callers need to be patched as well.
>  @option{-flive-patching=inline-clone} disables the following optimization flags:
>  @gccoptlist{-fwhole-program  -fipa-pta  -fipa-reference  -fipa-ra @gol
>  -fipa-icf  -fipa-icf-functions  -fipa-icf-variables @gol
> --fipa-bit-cp  -fipa-vrp  -fipa-pure-const  -fipa-reference-addressable @gol
> --fipa-stack-alignment}
> +-fipa-bit-cp  -fipa-vrp  -fipa-pure-const @gol
> +-fipa-reference-addressable -fipa-stack-alignment}
>  
>  @item inline-only-static
>  
> diff --git a/gcc/opts.c b/gcc/opts.c
> index 570155816e3..0b5e89faeee 100644
> --- a/gcc/opts.c
> +++ b/gcc/opts.c
> @@ -2347,7 +2347,7 @@ common_handle_option (struct gcc_options *opts,
>  
>      case OPT_flive_patching_:
>        if (value)
> -    	control_optimizations_for_live_patching (opts, opts_set,
> +	control_optimizations_for_live_patching (opts, opts_set,
>  						 opts->x_flag_live_patching);
>        break;
>  
> -- 
> 2.19.1
>