kbuild: fix ld-option function

The kbuild's ld-option function is broken because the command $(CC) /dev/null -c -o "$$TMPO" does not create object file! I have used a relatively old mips gcc 3.4.6 cross-compiler and a relatively new gcc 4.7.2 to check this fact but the results are the same. EXAMPLE: $ rm /tmp/1.o $ mips-linux-gcc /dev/null -c -o /tmp/1.o mips-linux-gcc: /dev/null: linker input file unused because linking not done $ ls -la /tmp/1.o ls: cannot access /tmp/1.o: No such file or directory We can easily fix the problem by adding the '-x c' compiler option. EXAMPLE: $ rm /tmp/1.o $ mips-linux-gcc -x c /dev/null -c -o /tmp/1.o $ ls -la /tmp/1.o -rw-r--r-- 1 antony antony 778 Apr 2 20:40 /tmp/1.o Also fix wrong ld-option example. Signed-off-by: Antony Pavlov <[email protected]> Signed-off-by: Michal Marek <[email protected]>
ambv · Apr 8, 2013 · 5b83df2 · 5b83df2
1 parent a937536
commit 5b83df2
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diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
@@ -593,7 +593,7 @@ more details, with real examples.
 
 	Example:
 		#Makefile
-		LDFLAGS_vmlinux += $(call really-ld-option, -X)
+		LDFLAGS_vmlinux += $(call ld-option, -X)
 
 
 === 4 Host Program support

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
@@ -148,7 +148,7 @@ cc-ldoption = $(call try-run,\
 # ld-option
 # Usage: LDFLAGS += $(call ld-option, -X)
 ld-option = $(call try-run,\
-	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
+	$(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
 
 # ar-option
 # Usage: KBUILD_ARFLAGS := $(call ar-option,D)