Re: [patch 2/7] enable unit-at-a-time optimisations for gcc4

Sam Ravnborg
2006-01-07T10:04:16Z

On Sat, Jan 07, 2006 at 01:07:57AM -0800, Andrew Morton wrote:

> From: Andrew Morton <akpm@osdl.org>
>
> Set GCC_VERSION up-front rather than in arch Makefiles. This reduces ordering
> problems and generally consolidates things.

This will fail if arch/Makefile for some reason redefine CC to something
else. I recall one arch did that in the past.

Two options:
1) Use $(call cc-version) all over the place.
2) Use '=' assignment to GCC_VERSION so value is evaluated only when
used.

I prefer the first version since we loose the optimzation that gcc is
called once anyway.

Sam

>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Arjan van de Ven <arjan@infradead.org>
> Signed-off-by: Andrew Morton <akpm@osdl.org>
> ---
>
> Makefile | 2 +-
> arch/ia64/Makefile | 1 -
> arch/parisc/Makefile | 4 ----
> arch/powerpc/Makefile | 2 --
> arch/ppc/Makefile | 1 -
> 5 files changed, 1 insertion(+), 9 deletions(-)
>
> diff -puN arch/ia64/Makefile~kbuild-call-gcc_version-earlier arch/ia64/Makefile
> --- devel/arch/ia64/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800
> +++ devel-akpm/arch/ia64/Makefile 2006-01-07 01:05:39.000000000 -0800
> @@ -25,7 +25,6 @@ cflags-y := -pipe $(EXTRA) -ffixed-r13 -
> -falign-functions=32 -frename-registers -fno-optimize-sibling-calls
> CFLAGS_KERNEL := -mconstant-gp
>
> -GCC_VERSION := $(call cc-version)
> GAS_STATUS = $(shell $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)")
> CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)")
>
> diff -puN arch/parisc/Makefile~kbuild-call-gcc_version-earlier arch/parisc/Makefile
> --- devel/arch/parisc/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800
> +++ devel-akpm/arch/parisc/Makefile 2006-01-07 01:05:39.000000000 -0800
> @@ -35,10 +35,6 @@ FINAL_LD=$(CROSS_COMPILE)ld --warn-commo
>
> OBJCOPY_FLAGS =-O binary -R .note -R .comment -S
>
> -GCC_VERSION := $(call cc-version)
> -ifneq ($(shell if [ -z $(GCC_VERSION) ] ; then echo "bad"; fi ;),)
> -$(error Sorry, couldn't find ($(cc-version)).)
> -endif
> ifneq ($(shell if [ $(GCC_VERSION) -lt 0303 ] ; then echo "bad"; fi ;),)
> $(error Sorry, your compiler is too old ($(GCC_VERSION)). GCC v3.3 or above is required.)
> endif
> diff -puN arch/powerpc/Makefile~kbuild-call-gcc_version-earlier arch/powerpc/Makefile
> --- devel/arch/powerpc/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800
> +++ devel-akpm/arch/powerpc/Makefile 2006-01-07 01:05:39.000000000 -0800
> @@ -76,7 +76,6 @@ LINUXINCLUDE += $(LINUXINCLUDE-y)
> CHECKFLAGS += -m$(SZ) -D__powerpc__ -D__powerpc$(SZ)__
>
> ifeq ($(CONFIG_PPC64),y)
> -GCC_VERSION := $(call cc-version)
> GCC_BROKEN_VEC := $(shell if [ $(GCC_VERSION) -lt 0400 ] ; then echo "y"; fi)
>
> ifeq ($(CONFIG_POWER4_ONLY),y)
> @@ -189,7 +188,6 @@ TOUT := .tmp_gas_check
> # Ensure this is binutils 2.12.1 (or 2.12.90.0.7) or later for altivec
> # instructions.
> # gcc-3.4 and binutils-2.14 are a fatal combination.
> -GCC_VERSION := $(call cc-version)
>
> checkbin:
> @if test "$(GCC_VERSION)" = "0304" ; then \
> diff -puN arch/ppc/Makefile~kbuild-call-gcc_version-earlier arch/ppc/Makefile
> --- devel/arch/ppc/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800
> +++ devel-akpm/arch/ppc/Makefile 2006-01-07 01:05:39.000000000 -0800
> @@ -128,7 +128,6 @@ TOUT := .tmp_gas_check
> # Ensure this is binutils 2.12.1 (or 2.12.90.0.7) or later for altivec
> # instructions.
> # gcc-3.4 and binutils-2.14 are a fatal combination.
> -GCC_VERSION := $(call cc-version)
>
> checkbin:
> @if test "$(GCC_VERSION)" = "0304" ; then \
> diff -puN Makefile~kbuild-call-gcc_version-earlier Makefile
> --- Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800
> +++ devel-akpm/Makefile 2006-01-07 01:05:39.000000000 -0800
> @@ -300,7 +300,7 @@ cc-option-align = $(subst -functions=0,,
> # Usage gcc-ver := $(call cc-version $(CC))
> cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
> $(if $(1), $(1), $(CC)))
> -
> +GCC_VERSION := $(call cc-version)
>
> # Look for make include files relative to root of kernel src
> MAKEFLAGS += --include-dir=$(srctree)
> _
>