kbuild: fix ld-option function

PATCH In review Antony Pavlov 2 participants 2 messages Apr 3, 2013 – Apr 8, 2013

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Antony Pavlov

author

2013-04-03 14:41 UTC #0 lore raw

PATCH v2 1/1 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]>

---
 Documentation/kbuild/makefiles.txt |    2 +-
 scripts/Kbuild.include             |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Documentation/kbuild/makefiles.txt +1 -1

index 5198b74..5836294 100644
@@ -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

scripts/Kbuild.include +1 -1

index 978416d..547e15d 100644
@@ -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)

Signature · 1 line

1.7.10.4

Michal Marek

2013-04-08 09:59 UTC #1 lore raw

Quoted 25 lines · Antony Pavlov

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

Quoted 7 lines

Also fix wrong ld-option example.
Signed-off-by Antony Pavlov <[email protected]>
---
 Documentation/kbuild/makefiles.txt |    2 +-
 scripts/Kbuild.include             |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Applied to kbuild.git#kbuild, thanks.

Michal