From 90ad4052e85cece1bbae064ff4b14088de35df29 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 14 Apr 2017 15:17:26 +0900 Subject: [PATCH] kbuild: avoid conflict between -ffunction-sections and -pg on gcc-4.7 Arnd Bergmann reported: "When ftrace is enabled and we build with gcc-4.7 or older, we get a warning for each file on architectures that select CONFIG_LD_DEAD_CODE_DATA_ELIMINATION: warning: -ffunction-sections disabled; it makes profiling impossible [enabled by default] " Since commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to cc-option to support clang"), warnings are treated as errors in cc-option checks. CC_FLAGS_FTRACE is blindly added to KBUILD_CFLAGS, so $(call cc-option,-ffunction-sections,) should be moved below it in order to detect the conflict between the two options. Reported-by: Arnd Bergmann Signed-off-by: Masahiro Yamada --- Makefile | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/Makefile b/Makefile index d26618608633..245852f7b312 100644 --- a/Makefile +++ b/Makefile @@ -632,11 +632,6 @@ include arch/$(SRCARCH)/Makefile KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) -ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION -KBUILD_CFLAGS += $(call cc-option,-ffunction-sections,) -KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) -endif - ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += $(call cc-option,-Oz,-Os) KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,) @@ -768,6 +763,11 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once) endif +ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION +KBUILD_CFLAGS += $(call cc-option,-ffunction-sections,) +KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) +endif + # arch Makefile may override CC so keep this after arch Makefile is included NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) CHECKFLAGS += $(NOSTDINC_FLAGS)