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| author | Andi Kleen <ak@linux.intel.com> | 2012-03-28 11:51:18 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2012-03-30 10:15:21 -0700 |
| commit | 1873e870fd63ee4b87dbe0125ca373e420fb4987 (patch) | |
| tree | 2c4d4244c653e374a1d0040e581be60f614f23a7 | |
| parent | 35372a7d45291140a97518a8d1c8cb0e31ee2bb7 (diff) | |
| download | lwn-1873e870fd63ee4b87dbe0125ca373e420fb4987.tar.gz lwn-1873e870fd63ee4b87dbe0125ca373e420fb4987.zip | |
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>
| -rw-r--r-- | Makefile | 10 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 9 |
2 files changed, 19 insertions, 0 deletions
@@ -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 6777153f18f3..4d3cbbbe4516 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 |