kbuild: avoid conflict between -ffunction-sections and -pg on gcc-4.7 (90ad4052) · Commits · 戴 / test

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 ("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 <arnd@arndb.de> Signed-off-by:

Masahiro Yamada <yamada.masahiro@socionext.com>

Makefile

+5 −5

Original line number	Diff line number	Diff line
		@@ -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)

Admin message