[patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Keith Owens]

Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
to suppress them.

Signed-off-by: Keith Owens <kaos@ocs.com.au>

Index: 2.6.12/Makefile
===================================================================
--- 2.6.12.orig/Makefile	2005-06-18 15:21:18.000000000 +1000
+++ 2.6.12/Makefile	2005-06-19 11:43:15.876218980 +1000
@@ -204,6 +204,8 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH"
 HOSTCC  	= gcc
 HOSTCXX  	= g++
 HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
+# disable pointer signedness warnings in gcc 4.0
+HOSTCFLAGS += $(call cc-option,-Wno-pointer-sign,)
 HOSTCXXFLAGS	= -O2
 
 # 	Decide whether to build built-in, modular, or both.

Re: [patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Mikael Pettersson]

On Sun, 19 Jun 2005 11:50:03 +1000, Keith Owens wrote:
>Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
>programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
>to suppress them.
>
>Signed-off-by: Keith Owens <kaos@ocs.com.au>
>
>Index: 2.6.12/Makefile
>===================================================================
>--- 2.6.12.orig/Makefile	2005-06-18 15:21:18.000000000 +1000
>+++ 2.6.12/Makefile	2005-06-19 11:43:15.876218980 +1000
>@@ -204,6 +204,8 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH"
> HOSTCC  	= gcc
> HOSTCXX  	= g++
> HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
>+# disable pointer signedness warnings in gcc 4.0
>+HOSTCFLAGS += $(call cc-option,-Wno-pointer-sign,)
> HOSTCXXFLAGS	= -O2

Please don't. Bogus code should be fixed, not hidden.

Re: [patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Russell King]

On Sun, Jun 19, 2005 at 11:23:37AM +0200, Mikael Pettersson wrote:
> On Sun, 19 Jun 2005 11:50:03 +1000, Keith Owens wrote:
> >Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
> >programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
> >to suppress them.
> >
> >Signed-off-by: Keith Owens <kaos@ocs.com.au>
> >
> >Index: 2.6.12/Makefile
> >===================================================================
> >--- 2.6.12.orig/Makefile	2005-06-18 15:21:18.000000000 +1000
> >+++ 2.6.12/Makefile	2005-06-19 11:43:15.876218980 +1000
> >@@ -204,6 +204,8 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH"
> > HOSTCC  	= gcc
> > HOSTCXX  	= g++
> > HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
> >+# disable pointer signedness warnings in gcc 4.0
> >+HOSTCFLAGS += $(call cc-option,-Wno-pointer-sign,)
> > HOSTCXXFLAGS	= -O2
> 
> Please don't. Bogus code should be fixed, not hidden.

cc-option checks to see if the flag is supported by $(CC) which could
be a completely different compiler from $(HOSTCC).  Hence the above
can incorrectly supply/fail to supply the argument.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: [patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Keith Owens]

On Sun, 19 Jun 2005 11:23:37 +0200 (MEST), 
Mikael Pettersson <mikpe@csd.uu.se> wrote:
>On Sun, 19 Jun 2005 11:50:03 +1000, Keith Owens wrote:
>>Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
>>programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
>>to suppress them.
>>
>>Signed-off-by: Keith Owens <kaos@ocs.com.au>
>>
>>Index: 2.6.12/Makefile
>>===================================================================
>>--- 2.6.12.orig/Makefile	2005-06-18 15:21:18.000000000 +1000
>>+++ 2.6.12/Makefile	2005-06-19 11:43:15.876218980 +1000
>>@@ -204,6 +204,8 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH"
>> HOSTCC  	= gcc
>> HOSTCXX  	= g++
>> HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
>>+# disable pointer signedness warnings in gcc 4.0
>>+HOSTCFLAGS += $(call cc-option,-Wno-pointer-sign,)
>> HOSTCXXFLAGS	= -O2
>
>Please don't. Bogus code should be fixed, not hidden.

The entire kernel, except the scripts directory, is already being
compiled with -Wno-pointer-sign, and has done since 2.6.12-rc1.  This
patch makes scripts consistent with the rest of the kernel.  The
-Wno-pointer-sign option was added to gcc 4 just for this problem.

If you feel that the code is bogus then turn off the option in your own
tree.  Be prepared for thousands of lines of warnings.

On Sun, 19 Jun 2005 10:58:33 +0100, 
Russell King <rmk+lkml@arm.linux.org.uk> wrote:

>cc-option checks to see if the flag is supported by $(CC) which could
>be a completely different compiler from $(HOSTCC).  Hence the above
>can incorrectly supply/fail to supply the argument.

Good point.  New patch.


Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
to suppress them.  HOSTCFLAGS change from '=' to ':=' to avoid
recursion problems.

Signed-off-by: Keith Owens <kaos@ocs.com.au>

Index: 2.6.12/Makefile
===================================================================
--- 2.6.12.orig/Makefile	2005-06-19 20:28:20.504999656 +1000
+++ 2.6.12/Makefile	2005-06-19 20:30:14.157877993 +1000
@@ -203,7 +203,11 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH"
 
 HOSTCC  	= gcc
 HOSTCXX  	= g++
-HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
+HOSTCFLAGS	:= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
+# disable pointer signedness warnings in gcc 4.0
+hostcc-option = $(shell if $(HOSTCC) $(HOSTCFLAGS) $(1) -S -o /dev/null -xc /dev/null \
+             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
+HOSTCFLAGS	+= $(call hostcc-option,-Wno-pointer-sign,)
 HOSTCXXFLAGS	= -O2
 
 # 	Decide whether to build built-in, modular, or both.

Re: [patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Jeff Garzik]

Keith Owens wrote:
> Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
> programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
> to suppress them.
> 
> Signed-off-by: Keith Owens <kaos@ocs.com.au>


Although I am a bit nervous about papering over these warnings without 
addressing them...  I still ACK the patch, because gcc4 on FC4 does 
indeed spew a bunch of noise.

Have you (or anyone) looked into the "root cause" of these warnings?

	Jeff

Re: [patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Sam Ravnborg]

> 
> >cc-option checks to see if the flag is supported by $(CC) which could
> >be a completely different compiler from $(HOSTCC).  Hence the above
> >can incorrectly supply/fail to supply the argument.
> 
> Good point.  New patch.

I am having this patch queued:

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2005/04/03 22:26:47+02:00 sam@mars.ravnborg.org 
#   kbuild: Use -Wno-pointer-sign when building for host
#   
#   Avoid lot's of useless warning when building host utilities.
#   A brave sould may take a look sometime - but not all warnings are correct.
#   
#   From: Pawel Sikora <pluto@pld-linux.org>
#   Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
# 
# Makefile
#   2005/04/03 22:26:24+02:00 sam@mars.ravnborg.org +12 -4
#   -Wno-pointer-sign for gcc 4.xx when compiling host programs
# 
diff -Nru a/Makefile b/Makefile
--- a/Makefile	2005-04-30 00:35:17 +02:00
+++ b/Makefile	2005-04-30 00:35:17 +02:00
@@ -201,10 +201,10 @@
 	  else if [ -x /bin/bash ]; then echo /bin/bash; \
 	  else echo sh; fi ; fi)
 
-HOSTCC  	= gcc
-HOSTCXX  	= g++
-HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
-HOSTCXXFLAGS	= -O2
+HOSTCC  	:= gcc
+HOSTCXX  	:= g++
+HOSTCFLAGS	:= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
+HOSTCXXFLAGS	:= -O2
 
 # 	Decide whether to build built-in, modular, or both.
 #	Normally, just do built-in.
@@ -538,6 +538,14 @@
 
 # disable pointer signedness warnings in gcc 4.0
 CFLAGS += $(call cc-option,-Wno-pointer-sign,)
+
+HOSTCFLAGS += $(shell if $(HOSTCC) $(HOSTCFLAGS) -Wno-pointer-sign -S \
+              -o /dev/null -xc /dev/null > /dev/null 2>&1; then \
+               echo "-Wno-pointer-sign"; fi ;)
+
+HOSTCXXFLAGS += $(shell if $(HOSTCXX) $(HOSTCXXFLAGS) -Wno-pointer-sign -S \
+              -o /dev/null -xc /dev/null > /dev/null 2>&1; then \
+               echo "-Wno-pointer-sign"; fi ;)
 
 # Default kernel image to build when no specific target is given.
 # KBUILD_IMAGE may be overruled on the commandline or

Re: [patch 2.6.12] Add -Wno-pointer-sign to HOSTCFLAGS

[Sam Ravnborg]

On Sun, Jun 19, 2005 at 10:02:41PM -0400, Jeff Garzik wrote:
> Keith Owens wrote:
> >Compiling 2.6.12 with gcc 4.0.0 (FC4) gets lots of warnings for the
> >programs in the scripts directory.  Add -Wno-pointer-sign to HOSTCFLAGS
> >to suppress them.
> >
> >Signed-off-by: Keith Owens <kaos@ocs.com.au>
> 
> 
> Although I am a bit nervous about papering over these warnings without 
> addressing them...  I still ACK the patch, because gcc4 on FC4 does 
> indeed spew a bunch of noise.
> 
> Have you (or anyone) looked into the "root cause" of these warnings?
I've receive a few pathes to scripts/ fixing this.
They almost all just used casts to hide the warning but some included
real fixes. They are all lost for now though.

	Sam