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debug: Add CONFIG_READABLE_ASM 

Add a config option to disable various gcc compiler optimizations that
make assembler listings much harder to read. This is everything that reorders
code significantly or creates partial functions.

This is mainly to keep kernel hackers sane.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1332960678-11879-2-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Andi Kleen 2012-03-28 11:51:18 -07:00 committed by H. Peter Anvin
parent 35372a7d45
commit 1873e870fd
2 changed files with 19 additions and 0 deletions
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10
Makefile
View File

@ -564,6 +564,16 @@ else
KBUILD_CFLAGS += -O2
endif
ifdef CONFIG_READABLE_ASM
# Disable optimizations that make assembler listings hard to read.
# reorder blocks reorders the control in the function
# ipa clone creates specialized cloned functions
# partial inlining inlines only parts of functions
KBUILD_CFLAGS += $(call cc-option,-fno-reorder-blocks,) \
$(call cc-option,-fno-ipa-cp-clone,) \
$(call cc-option,-fno-partial-inlining)
endif
include $(srctree)/arch/$(SRCARCH)/Makefile
ifneq ($(CONFIG_FRAME_WARN),0)

9
lib/Kconfig.debug
View File

@ -70,6 +70,15 @@ config STRIP_ASM_SYMS
that look like '.Lxxx') so they don't pollute the output of
get_wchan() and suchlike.
config READABLE_ASM
bool "Generate readable assembler code"
depends on DEBUG_KERNEL
help
Disable some compiler optimizations that tend to generate human unreadable
assembler output. This may make the kernel slightly slower, but it helps
to keep kernel developers who have to stare a lot at assembler listings
sane.
config UNUSED_SYMBOLS
bool "Enable unused/obsolete exported symbols"
default y if X86