Reduce build times

U-Boot Makefiles contain a number of tests for compiler features etc.
which so far are executed again and again.  On some architectures
(especially ARM) this results in a large number of calls to gcc.

This patch makes sure to run such tests only once, thus largely
reducing the number of "execve" system calls.

Example: number of "execve" system calls for building the "P2020DS"
(Power Architecture) and "qong" (ARM) boards, measured as:
	-> strace -f -e trace=execve -o /tmp/foo ./MAKEALL <board>
	-> grep execve /tmp/foo | wc -l

	Before: After:	Reduction:
==================================
P2020DS 20555	15205	-26%
qong	31692	14490	-54%

As a result, built times are significantly reduced, typically by
30...50%.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Andy Fleming <afleming@gmail.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Albert Aribaud <albert.aribaud@free.fr>
cc: Graeme Russ <graeme.russ@gmail.com>
cc: Mike Frysinger <vapier@gentoo.org>
Tested-by: Graeme Russ <graeme.russ@gmail.com>
Tested-by: Matthias Weisser <weisserm@arcor.de>
Tested-by: Sanjeev Premi <premi@ti.com>
Tested-by: Simon Glass <sjg@chromium.org>
Tested-by: Macpaul Lin <macpaul@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>

Makefile

@@ -320,7 +320,7 @@ else
 PLATFORM_LIBGCC = -L $(USE_PRIVATE_LIBGCC) -lgcc
 endif
 else
-PLATFORM_LIBGCC = -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc
+PLATFORM_LIBGCC := -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc
 endif
 PLATFORM_LIBS += $(PLATFORM_LIBGCC)
 export PLATFORM_LIBS

arch/arm/config.mk

@@ -34,7 +34,7 @@ endif
 PLATFORM_CPPFLAGS += -DCONFIG_ARM -D__ARM__
 
 # Explicitly specifiy 32-bit ARM ISA since toolchain default can be -mthumb:
-PLATFORM_CPPFLAGS += $(call cc-option,-marm,)
+PF_CPPFLAGS_ARM := $(call cc-option,-marm,)
 
 # Try if EABI is supported, else fall back to old API,
 # i. e. for example:
@@ -44,15 +44,16 @@ PLATFORM_CPPFLAGS += $(call cc-option,-marm,)
 #	-mabi=apcs-gnu -mno-thumb-interwork
 # - with ELDK 3.1 (gcc 3.x), use:
 #	-mapcs-32 -mno-thumb-interwork
-PLATFORM_CPPFLAGS += $(call cc-option,\
-				-mabi=aapcs-linux -mno-thumb-interwork,\
+PF_CPPFLAGS_ABI := $(call cc-option,\
+			-mabi=aapcs-linux -mno-thumb-interwork,\
+			$(call cc-option,\
+				-mapcs-32,\
 				$(call cc-option,\
-					-mapcs-32,\
-					$(call cc-option,\
-						-mabi=apcs-gnu,\
-					)\
-				) $(call cc-option,-mno-thumb-interwork,)\
-			)
+					-mabi=apcs-gnu,\
+				)\
+			) $(call cc-option,-mno-thumb-interwork,)\
+		)
+PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_ARM) $(PF_CPPFLAGS_ABI)
 
 # For EABI, make sure to provide raise()
 ifneq (,$(findstring -mabi=aapcs-linux,$(PLATFORM_CPPFLAGS)))

arch/arm/cpu/arm1136/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS += -march=armv5
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm1176/config.mk

@@ -29,4 +29,6 @@ PLATFORM_CPPFLAGS += -march=armv5t
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,\
+			$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm1176/s3c64xx/config.mk

@@ -29,4 +29,6 @@ PLATFORM_CPPFLAGS += -march=armv5t
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,\
+			$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm720t/config.mk

@@ -30,4 +30,6 @@ PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,\
+			$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm920t/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS += -march=armv4
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm925t/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS += -march=armv4
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm926ejs/at91/config.mk

@@ -1 +1,2 @@
-PLATFORM_CPPFLAGS += $(call cc-option,-mtune=arm926ejs,)
+PF_CPPFLAGS_TUNE := $(call cc-option,-mtune=arm926ejs,)
+PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_TUNE)

arch/arm/cpu/arm926ejs/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS += -march=armv5te
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm946es/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS +=  -march=armv4
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/arm_intcm/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS +=  -march=armv4
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/armv7/config.mk

@@ -29,5 +29,5 @@ PLATFORM_CPPFLAGS += -march=armv5
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,\
-		    $(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/armv7/omap-common/config.mk

@@ -29,5 +29,6 @@ PLATFORM_CPPFLAGS += -march=armv5
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,\
-		    $(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,\
+			$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/ixp/config.mk

@@ -37,4 +37,5 @@ LDFLAGS_u-boot += --gc-sections
 # Supply options according to compiler version
 #
 # =========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/lh7a40x/config.mk

@@ -29,4 +29,5 @@ PLATFORM_CPPFLAGS += -march=armv4
 # Supply options according to compiler version
 #
 # ========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/pxa/config.mk

@@ -30,4 +30,5 @@ PLATFORM_CPPFLAGS += -march=armv5te -mtune=xscale
 # Supply options according to compiler version
 #
 # ========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/s3c44b0/config.mk

@@ -30,4 +30,5 @@ PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi -msoft-float
 # Supply options according to compiler version
 #
 # ========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/arm/cpu/sa1100/config.mk

@@ -30,4 +30,5 @@ PLATFORM_CPPFLAGS += -march=armv4 -mtune=strongarm1100
 # Supply options according to compiler version
 #
 # ========================================================================
-PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PF_RELFLAGS_SLB_AT := $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
+PLATFORM_RELFLAGS += $(PF_RELFLAGS_SLB_AT)

arch/powerpc/cpu/mpc824x/Makefile

@@ -23,8 +23,7 @@
 
 include $(TOPDIR)/config.mk
 ifneq ($(OBJTREE),$(SRCTREE))
-$(shell mkdir -p $(obj)drivers/epic)
-$(shell mkdir -p $(obj)drivers/i2c)
+$(shell mkdir -p $(obj)drivers/epic $(obj)drivers/i2c)
 endif
 
 LIB	= $(obj)lib$(CPU).o

arch/powerpc/cpu/mpc85xx/config.mk

@@ -28,5 +28,6 @@ PLATFORM_CPPFLAGS += -ffixed-r2 -Wa,-me500 -msoft-float -mno-string
 # -mspe=yes is needed to have -mno-spe accepted by a buggy GCC;
 # see "[PATCH,rs6000] make -mno-spe work as expected" on
 # http://gcc.gnu.org/ml/gcc-patches/2008-04/msg00311.html
-PLATFORM_CPPFLAGS +=$(call cc-option,-mspe=yes)
-PLATFORM_CPPFLAGS +=$(call cc-option,-mno-spe)
+PF_CPPFLAGS_SPE := $(call cc-option,-mspe=yes) \
+		   $(call cc-option,-mno-spe)
+PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_SPE)

arch/x86/config.mk

@@ -27,10 +27,12 @@ PLATFORM_CPPFLAGS += -fno-strict-aliasing
 PLATFORM_CPPFLAGS += -Wstrict-prototypes
 PLATFORM_CPPFLAGS += -mregparm=3
 PLATFORM_CPPFLAGS += -fomit-frame-pointer
-PLATFORM_CPPFLAGS += $(call cc-option, -ffreestanding)
-PLATFORM_CPPFLAGS += $(call cc-option, -fno-toplevel-reorder,  $(call cc-option, -fno-unit-at-a-time))
-PLATFORM_CPPFLAGS += $(call cc-option, -fno-stack-protector)
-PLATFORM_CPPFLAGS += $(call cc-option, -mpreferred-stack-boundary=2)
+PF_CPPFLAGS_X86   := $(call cc-option, -ffreestanding) \
+		     $(call cc-option, -fno-toplevel-reorder, \
+		       $(call cc-option, -fno-unit-at-a-time)) \
+		     $(call cc-option, -fno-stack-protector) \
+		     $(call cc-option, -mpreferred-stack-boundary=2)
+PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_X86)
 PLATFORM_CPPFLAGS += -fno-dwarf2-cfi-asm
 PLATFORM_CPPFLAGS += -DREALMODE_BASE=0x7c0
 

board/siemens/SCM/Makefile

@@ -24,8 +24,7 @@
 include $(TOPDIR)/config.mk
 
 ifneq ($(OBJTREE),$(SRCTREE))
-$(shell mkdir -p $(obj)../common)
-$(shell mkdir -p $(obj)../../tqc/tqm8xx)
+$(shell mkdir -p $(obj)../common $(obj)../../tqc/tqm8xx)
 endif
 
 LIB	= $(obj)lib$(BOARD).o

config.mk

@@ -209,11 +209,13 @@ else
 CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes
 endif
 
-CFLAGS += $(call cc-option,-fno-stack-protector)
+CFLAGS_SSP := $(call cc-option,-fno-stack-protector)
+CFLAGS += $(CFLAGS_SSP)
 # Some toolchains enable security related warning flags by default,
 # but they don't make much sense in the u-boot world, so disable them.
-CFLAGS += $(call cc-option,-Wno-format-nonliteral)
-CFLAGS += $(call cc-option,-Wno-format-security)
+CFLAGS_WARN := $(call cc-option,-Wno-format-nonliteral) \
+	       $(call cc-option,-Wno-format-security)
+CFLAGS += $(CFLAGS_WARN)
 
 # $(CPPFLAGS) sets -g, which causes gcc to pass a suitable -g<format>
 # option to the assembler.

examples/standalone/Makefile

@@ -85,7 +85,8 @@ endif
 # We don't want gcc reordering functions if possible.  This ensures that an
 # application's entry point will be the first function in the application's
 # source file.
-CFLAGS += $(call cc-option,-fno-toplevel-reorder)
+CFLAGS_NTR := $(call cc-option,-fno-toplevel-reorder)
+CFLAGS += $(CFLAGS_NTR)
 
 all:	$(obj).depend $(OBJS) $(LIB) $(SREC) $(BIN) $(ELF)