kbuild: introduce ld-option
ld-option is used to check if $(LD) supports a specific option.
Based on patch from Andi Kleen.
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
First use is to check if option -X is supported (upcoming patch).
Theis is ne
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 7847fce..71c602d 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -18,6 +18,7 @@
--- 3.9 Dependency tracking
--- 3.10 Special Rules
--- 3.11 $(CC) support functions
+ --- 3.12 $(LD) support functions
=== 4 Host Program support
--- 4.1 Simple Host Program
@@ -570,6 +571,19 @@
endif
endif
+--- 3.12 $(LD) support functions
+
+ ld-option
+ ld-option is used to check if $(LD) supports the supplied option.
+ ld-option takes two options as arguments.
+ The second argument is an optional option that can be used if the
+ first option is not supported by $(LD).
+
+ Example:
+ #Makefile
+ LDFLAGS_vmlinux += $(call really-ld-option, -X)
+
+
=== 4 Host Program support
Kbuild supports building executables on the host for use during the
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 94a4f68..b345260 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -83,11 +83,12 @@
# is automatically cleaned up.
try-run = $(shell set -e; \
TMP="$(TMPOUT).$$$$.tmp"; \
+ TMPO="$(TMPOUT).$$$$.o"; \
if ($(1)) >/dev/null 2>&1; \
then echo "$(2)"; \
else echo "$(3)"; \
fi; \
- rm -f "$$TMP")
+ rm -f "$$TMP" "$$TMPO")
# as-option
# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
@@ -135,6 +136,11 @@
cc-ldoption = $(call try-run,\
$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
+# ld-option
+# Usage: LDFLAGS += $(call ld-option, -X)
+ld-option = $(call try-run,\
+ $(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
+
######
###