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Message-Id: <1332960678-11879-2-git-send-email-andi@firstfloor.org> Date: Wed, 28 Mar 2012 11:51:18 -0700 From: Andi Kleen <andi@...stfloor.org> To: linux-kernel@...r.kernel.org Cc: x86@...nel.org, Andi Kleen <ak@...ux.intel.com> Subject: [PATCH 2/2] Add CONFIG_READABLE_ASM From: Andi Kleen <ak@...ux.intel.com> 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@...ux.intel.com> --- Makefile | 10 ++++++++++ lib/Kconfig.debug | 9 +++++++++ 2 files changed, 19 insertions(+), 0 deletions(-) diff --git a/Makefile b/Makefile index 1932984..6f7328b 100644 --- a/Makefile +++ b/Makefile @@ -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) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index f7af95d..d6102f3 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -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 -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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