From 1873e870fd63ee4b87dbe0125ca373e420fb4987 Mon Sep 17 00:00:00 2001 From: Andi Kleen <ak@linux.intel.com> Date: Wed, 28 Mar 2012 11:51:18 -0700 Subject: [PATCH] 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> --- Makefile | 10 ++++++++++ lib/Kconfig.debug | 9 +++++++++ 2 files changed, 19 insertions(+) diff --git a/Makefile b/Makefile index 1932984478c17..6f7328bca9c42 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 6777153f18f31..4d3cbbbe4516a 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 -- GitLab