build system: Split linking into multiple steps
After collecting dependencies for ramstage, add an intermediate step
in which object files are linked per directory. The results are then
linked into the final binary.
This reduces the maximum command line length and might also help with
future use of LTO linking.
Also adapt the lint test for build dir handling, since printall
doesn't provide individual object files for ramstage anymore.
Change-Id: Ie40febd8c1eaf4609944eedeab46d870639e53df
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/1911
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/Makefile.inc b/Makefile.inc
index 5b62dd3..7caf359 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -60,6 +60,40 @@
# Add source classes and their build options
classes-y := ramstage romstage smm cpu_microcode
+#######################################################################
+# Helper functions for ramstage postprocess
+spc :=
+spc +=
+$(spc) :=
+$(spc) +=
+
+# files-in-dir-recursive,dir,files
+files-in-dir-recursive=$(filter $(1)%,$(2))
+
+# parent-dir,dir/
+parent-dir=$(dir $(subst $( ),/,$(strip $(subst /, ,$(1)))))
+
+# filters out exactly the directory specified
+# filter-out-dir,dir_to_keep,dirs
+filter-out-dir=$(filter-out $(1),$(2))
+
+# filters out dir_to_keep and all its parents
+# filter-out-dirs,dir_to_keep,dirs
+filter-out-dirs=$(if $(filter-out ./,$(1)),$(call filter-out-dirs,$(call parent-dir,$(1)),$(call filter-out-dir,$(1),$(2))),$(call filter-out-dir,$(1),$(2)))
+
+# dir-wildcards,dirs
+dir-wildcards=$(addsuffix %,$(1))
+
+# files-in-dir,dir,files
+files-in-dir=$(filter-out $(call dir-wildcards,$(call filter-out-dirs,$(1),$(dir $(2)))),$(call files-in-dir-recursive,$(1),$(2)))
+
+#######################################################################
+# reduce command line length by linking the objects of each
+# directory into an intermediate file
+ramstage-postprocess=$(foreach d,$(sort $(dir $(1))), \
+ $(eval $(d)ramstage.o: $(call files-in-dir,$(d),$(1)); $$(LD) -o $$@ -r $$^ ) \
+ $(eval ramstage-objs:=$(d)ramstage.o $(filter-out $(call files-in-dir,$(d),$(1)),$(ramstage-objs))))
+
romstage-c-ccopts:=-D__PRE_RAM__
romstage-S-ccopts:=-D__PRE_RAM__
ifeq ($(CONFIG_TRACE),y)