[coreboot] [PATCH] v3: optional compilation with -fwhole-program

[Carl-Daniel Hailfinger]

Enable compilation with -fwhole-program for initram. The setting can be
chosen via Kconfig. Default off.
Depending on the target, this saves between 10% and 20% of initram size.

Compilation still broken for:
- ADL MSM800SEV
- Gigabyte M57SLI

Compilation changed for:
- AMD DB800 (checker doesn't trigger anymore, but we get an unresolved
symbol instead)
- AMD Norwich (same)
(The compilation changes are not bad per se, just a bit misleading. It
seems that gcc is really smart.)

Compilation OK for:
- AMD Serengeti
- Artec DBE61
- Artec DBE62
- PCEngines Alix.1C
- PCEngines Alix.2C3

Signed-off-by: Carl-Daniel Hailfinger

Index: corebootv3-initram_fwholeprogram/Kconfig
===================================================================
--- corebootv3-initram_fwholeprogram/Kconfig	(Revision 821)
+++ corebootv3-initram_fwholeprogram/Kconfig	(Arbeitskopie)
@@ -60,6 +60,16 @@
    help
      Enable this option to make coreboot beep upon certain events.

+config BADASS_OPTIMIZATION
+	bool "Enable badass optimizations"
+	depends EXPERT && EXPERIMENTAL
+	help
+	  Enable -fwhole-program -combine for select code.
+	  Needs lots of annotation in stage1 and stage2.
+	  Works for initram only.
+
+	  If you are a Gentoo user, say NO!
+
 endmenu

source mainboard/Kconfig
Index: corebootv3-initram_fwholeprogram/arch/x86/Makefile
===================================================================
--- corebootv3-initram_fwholeprogram/arch/x86/Makefile	(Revision 821)
+++ corebootv3-initram_fwholeprogram/arch/x86/Makefile	(Arbeitskopie)
@@ -132,6 +132,12 @@
    PARSEELF = -e
 endif

+ifeq ($(CONFIG_BADASS_OPTIMIZATION), y)
+	COMBINEFLAGS = -fwhole-program
+else
+	COMBINEFLAGS =
+endif
+
 STAGE0_SRC := $(patsubst %,$(src)/lib/%,$(STAGE0_LIB_SRC)) \
          $(patsubst %,$(src)/arch/x86/%,$(STAGE0_ARCH_X86_SRC)) \
          $(STAGE0_MAINBOARD_SRC) $(STAGE0_CHIPSET_SRC)
@@ -268,7 +274,7 @@

$(obj)/coreboot.initram $(obj)/coreboot.initram.map: $(obj)/stage0.init $(obj)/stage0-prefixed.o $(INITRAM_SRC)
    $(Q)printf "  CC      $(subst $(shell pwd)/,,$(@)) (XIP)\n"
-	$(Q)$(CC) $(INITCFLAGS) -fPIE -c -combine $(INITRAM_SRC) -o $(obj)/coreboot.initram_partiallylinked.o
+	$(Q)$(CC) $(INITCFLAGS) -fPIE -c -combine $(COMBINEFLAGS) $(INITRAM_SRC) -o $(obj)/coreboot.initram_partiallylinked.o

$(Q)# .data and .bss must be empty because they aren't handled
    $(Q)printf "  CHECK   initram (non-empty writable/allocatable sections)\n"