Re: [PATCH 01/18] Added hacking menu for override optimization by GCC.

[Randy Dunlap <rdunlap@xenotime.net>]

On 02/16/2012 06:31 AM, Radosław Smogura wrote:
> From: mail@smogura.eu <mail@smogura.eu>
> 
> This patch gives ability for add some "-fno-..." options for GCC
> and to force -O1 optimization. Supporting files, like Kconfig, Makefile
> are auto-generated due to large amount of available options.
> 
> Patch helps to debug kernel.

Note: I only see patches 1-10.

I fix a few typos below (comments in the generated files only).


> ---
>  Makefile                           |   11 ++++
>  lib/Kconfig.debug                  |    2 +
>  lib/Kconfig.debug.optim            |  102 ++++++++++++++++++++++++++++++++++++
>  scripts/Makefile.optim.inc         |   23 ++++++++
>  scripts/debug/make_config_optim.sh |   88 +++++++++++++++++++++++++++++++
>  5 files changed, 226 insertions(+), 0 deletions(-)
>  create mode 100644 lib/Kconfig.debug.optim
>  create mode 100644 scripts/Makefile.optim.inc
>  create mode 100644 scripts/debug/make_config_optim.sh
> 
> diff --git a/Makefile b/Makefile
> index 7c44b67..bc9a961 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -558,12 +558,23 @@ endif # $(dot-config)
>  # Defaults to vmlinux, but the arch makefile usually adds further targets
>  all: vmlinux
>  
> +ifdef CONFIG_HACK_OPTIM_FORCE_O1_LEVEL
> +KBUILD_CFLAGS += -O1
> +else
> +
>  ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
>  KBUILD_CFLAGS	+= -Os
>  else
>  KBUILD_CFLAGS	+= -O2
>  endif
>  
> +endif
> +
> +# Include makefile for optimization override
> +ifdef CONFIG_HACK_OPTIM
> +include $(srctree)/scripts/Makefile.optim.inc
> +endif
> +
>  include $(srctree)/arch/$(SRCARCH)/Makefile
>  
>  ifneq ($(CONFIG_FRAME_WARN),0)
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 8745ac7..928265e 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1274,5 +1274,7 @@ source "lib/Kconfig.kgdb"
>  
>  source "lib/Kconfig.kmemcheck"
>  
> +source "lib/Kconfig.debug.optim"
> +
>  config TEST_KSTRTOX
>  	tristate "Test kstrto*() family of functions at runtime"
> diff --git a/lib/Kconfig.debug.optim b/lib/Kconfig.debug.optim
> new file mode 100644
> index 0000000..09b1012
> --- /dev/null
> +++ b/lib/Kconfig.debug.optim
> @@ -0,0 +1,102 @@
> +# This file was auto generated. It's utility configuration

                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
That sentence(?) (fragment?) is not helpful.  I would drop it.

> +# Distributed under GPL v2 License
> +
> +menuconfig HACK_OPTIM
> +	bool "Allows to override GCC optimization"

	      Allows the user to override GCC optimization

> +	depends on DEBUG_KERNEL && EXPERIMENTAL
> +	help
> +	  If you say Y here you will be able to override
> +	  how GCC optimize kernel code. This will create

	          optimizes

> +	  more debug friendly, but with not guarentee

	             friendly code, but will not guarantee

> +	  about same runi, like production, kernel.

	  the same running, like a production kernel.

> +
> +	  If you say Y here probably You will want say

	                             you will want to say Y

> +	  for all suboptions

	  for all suboptions.

> +
> +if HACK_OPTIM
> +
> +config HACK_OPTIM_FORCE_O1_LEVEL
> +	bool "Forces -O1 optimization level"
> +	---help---
> +	  This will change how GCC optimize code. Code

	                           optimizes

> +	  may be slower and larger but will be more debug
> +	  "friendly".
> +
> +	  In some cases there is low chance that kernel
> +	  will run different then normal, reporting or not

	  will run differently than normal,

> +	  some bugs or errors. Refere to GCC manual for

	                       Refer

> +	  more details.
> +
> +	  You SHOULD say N here.
> +
> +config HACK_OPTIM__fno_inline_functions_called_once
> +	bool "Adds -fno-inline-functions-called-once parameter to gcc invoke line."
> +	---help---
> +	  This will change how GCC optimize code. Code

	                           optimizes

> +	  may be slower and larger but will be more debug
> +	  "friendly".
> +
> +	  In some cases there is low chance that kernel
> +	  will run different then normal, reporting or not

	  will run differently than normal,

> +	  some bugs or errors. Refere to GCC manual for

	                       Refer

> +	  more details.
> +
> +	  You SHOULD say N here.
> +
> +config HACK_OPTIM__fno_combine_stack_adjustments
> +	bool "Adds -fno-combine-stack-adjustments parameter to gcc invoke line."
> +	---help---
> +	  This will change how GCC optimize code. Code

	                           optimizes

> +	  may be slower and larger but will be more debug
> +	  "friendly".
> +
> +	  In some cases there is low chance that kernel
> +	  will run different then normal, reporting or not

	  will run differently than normal,

> +	  some bugs or errors. Refere to GCC manual for

	                       Refer

> +	  more details.
> +
> +	  You SHOULD say N here.
> +
> +config HACK_OPTIM__fno_tree_dce
> +	bool "Adds -fno-tree-dce parameter to gcc invoke line."
> +	---help---
> +	  This will change how GCC optimize code. Code

	                           optimizes

> +	  may be slower and larger but will be more debug
> +	  "friendly".
> +
> +	  In some cases there is low chance that kernel
> +	  will run different then normal, reporting or not

	  will run differently than normal,

> +	  some bugs or errors. Refere to GCC manual for

	                       Refer

> +	  more details.
> +
> +	  You SHOULD say N here.
> +
> +config HACK_OPTIM__fno_tree_dominator_opts
> +	bool "Adds -fno-tree-dominator-opts parameter to gcc invoke line."
> +	---help---
> +	  This will change how GCC optimize code. Code

same ...

> +	  may be slower and larger but will be more debug
> +	  "friendly".
> +
> +	  In some cases there is low chance that kernel
> +	  will run different then normal, reporting or not
> +	  some bugs or errors. Refere to GCC manual for
> +	  more details.
> +
> +	  You SHOULD say N here.
> +
> +config HACK_OPTIM__fno_dse
> +	bool "Adds -fno-dse parameter to gcc invoke line."
> +	---help---
> +	  This will change how GCC optimize code. Code

same ...

> +	  may be slower and larger but will be more debug
> +	  "friendly".
> +
> +	  In some cases there is low chance that kernel
> +	  will run different then normal, reporting or not
> +	  some bugs or errors. Refere to GCC manual for
> +	  more details.
> +
> +	  You SHOULD say N here.
> +
> +endif #HACK_OPTIM
> diff --git a/scripts/Makefile.optim.inc b/scripts/Makefile.optim.inc
> new file mode 100644
> index 0000000..e78cc92
> --- /dev/null
> +++ b/scripts/Makefile.optim.inc
> @@ -0,0 +1,23 @@
> +# This file was auto generated. It's utility configuration
> +# Distributed under GPL v2 License
> +
> +ifdef CONFIG_HACK_OPTIM__fno_inline_functions_called_once
> +	KBUILD_CFLAGS += -fno-inline-functions-called-once
> +endif
> +
> +ifdef CONFIG_HACK_OPTIM__fno_combine_stack_adjustments
> +	KBUILD_CFLAGS += -fno-combine-stack-adjustments
> +endif
> +
> +ifdef CONFIG_HACK_OPTIM__fno_tree_dce
> +	KBUILD_CFLAGS += -fno-tree-dce
> +endif
> +
> +ifdef CONFIG_HACK_OPTIM__fno_tree_dominator_opts
> +	KBUILD_CFLAGS += -fno-tree-dominator-opts
> +endif
> +
> +ifdef CONFIG_HACK_OPTIM__fno_dse
> +	KBUILD_CFLAGS += -fno-dse
> +endif
> +
> diff --git a/scripts/debug/make_config_optim.sh b/scripts/debug/make_config_optim.sh
> new file mode 100644
> index 0000000..26865923
> --- /dev/null
> +++ b/scripts/debug/make_config_optim.sh
> @@ -0,0 +1,88 @@
> +#!/bin/sh
> +
> +## Utility script for generating optimization override options
> +## for kernel compilation.
> +##
> +## Distributed under GPL v2 license
> +## (c) Radosław Smogura, 2011
> +
> +# Prefix added for variable
> +CFG_PREFIX="HACK_OPTIM"
> +
> +KCFG="Kconfig.debug.optim"
> +MKFI="Makefile.optim.inc"
> +
> +OPTIMIZATIONS_PARAMS="-fno-inline-functions-called-once \
> + -fno-combine-stack-adjustments \
> + -fno-tree-dce \
> + -fno-tree-dominator-opts \
> + -fno-dse "
> +
> +echo "# This file was auto generated. It's utility configuration" > $KCFG
> +echo "# Distributed under GPL v2 License" >> $KCFG
> +echo >> $KCFG
> +echo "menuconfig ${CFG_PREFIX}" >> $KCFG
> +echo -e "\tbool \"Allows to override GCC optimization\"" >> $KCFG
> +echo -e "\tdepends on DEBUG_KERNEL && EXPERIMENTAL" >> $KCFG
> +echo -e "\thelp" >> $KCFG
> +echo -e "\t  If you say Y here you will be able to override" >> $KCFG
> +echo -e "\t  how GCC optimize kernel code. This will create" >> $KCFG
> +echo -e "\t  more debug friendly, but with not guarentee"    >> $KCFG
> +echo -e "\t  about same runi, like production, kernel."      >> $KCFG
> +echo >> $KCFG
> +echo -e "\t  If you say Y here probably You will want say"   >> $KCFG
> +echo -e "\t  for all suboptions" >> $KCFG
> +echo >> $KCFG
> +echo "if ${CFG_PREFIX}" >> $KCFG
> +echo >> $KCFG
> +
> +echo "# This file was auto generated. It's utility configuration" > $MKFI
> +echo "# Distributed under GPL v2 License" >> $MKFI
> +echo >> $MKFI
> +
> +# Insert standard override optimization level
> +# This is exception, and this value will not be included
> +# in auto generated makefile. Support for this value
> +# is hard coded in main Makefile.
> +echo -e "config ${CFG_PREFIX}_FORCE_O1_LEVEL" >> $KCFG
> +echo -e "\tbool \"Forces -O1 optimization level\"" >> $KCFG
> +echo -e "\t---help---" >> $KCFG
> +echo -e "\t  This will change how GCC optimize code. Code" >> $KCFG
> +echo -e "\t  may be slower and larger but will be more debug" >> $KCFG
> +echo -e "\t  \"friendly\"." >> $KCFG
> +echo >> $KCFG
> +echo -e "\t  In some cases there is low chance that kernel" >> $KCFG
> +echo -e "\t  will run different then normal, reporting or not" >> $KCFG
> +echo -e "\t  some bugs or errors. Refere to GCC manual for" >> $KCFG
> +echo -e "\t  more details." >> $KCFG
> +echo >> $KCFG
> +echo -e "\t  You SHOULD say N here." >> $KCFG
> +echo >> $KCFG
> +
> +for o in $OPTIMIZATIONS_PARAMS ; do
> +	cfg_o="${CFG_PREFIX}_${o//-/_}";
> +	echo "Processing param ${o} config variable will be $cfg_o";
> +
> +	# Generate kconfig entry
> +	echo -e "config ${cfg_o}" >> $KCFG
> +	echo -e "\tbool \"Adds $o parameter to gcc invoke line.\"" >> $KCFG
> +	echo -e "\t---help---" >> $KCFG
> +	echo -e "\t  This will change how GCC optimize code. Code" >> $KCFG
> +	echo -e "\t  may be slower and larger but will be more debug" >> $KCFG
> +	echo -e "\t  \"friendly\"." >> $KCFG
> +	echo >> $KCFG
> +	echo -e "\t  In some cases there is low chance that kernel" >> $KCFG
> +	echo -e "\t  will run different then normal, reporting or not" >> $KCFG
> +	echo -e "\t  some bugs or errors. Refere to GCC manual for" >> $KCFG
> +	echo -e "\t  more details." >> $KCFG
> +	echo >> $KCFG
> +	echo -e "\t  You SHOULD say N here." >> $KCFG
> +	echo >> $KCFG
> +
> +	#Generate Make for include
> +	echo "ifdef CONFIG_${cfg_o}" >> $MKFI
> +	echo -e "\tKBUILD_CFLAGS += $o" >> $MKFI
> +	echo "endif" >> $MKFI
> +	echo  >> $MKFI
> +done;
> +echo "endif #${CFG_PREFIX}" >> $KCFG


-- 
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>