[RS6000] Don't pass --oformat to ld

[RS6000] Don't pass --oformat to ld

[Alan Modra]

bugzilla.redhat.com/show_bug_cgi?id=1255946 shows that gcc built with
both powerpc64-linux and powerpc64le-linux support passes wrong linker
options when trying to link in the non-default endian.  A --oformat
option coming from LINK_TARGET_SPEC is only correct for 32-bit.

It turns out that GNU ld -m options select a particular ld emulation
(e*.c file in ld build dir) which provides compiled-in scripts or
selects a script from ldscripts/.  Each of these has an OUTPUT_FORMAT
statement, which does the same thing as --oformat.  --oformat is
therefore redundant when using GNU ld built this century, except
possibly when a user overrides the default ld script with -Wl,-T and
their script neglects OUTPUT_FORMAT, and it isn't the default output.
I don't think it's worth fixing this possible use case.

Bootstrap and testing in progress.  OK for mainline assuming all is
OK?

	* config/rs6000/sysv4le.h (LINK_TARGET_SPEC): Don't define.
	* config/rs6000/sysv4.h (LINK_TARGET_SPEC): Likewise.
	(LINK_SPEC, SUBTARGET_EXTRA_SPECS): Delete link_target.

diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index 24618e3..f48af43 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -574,7 +574,6 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 %{R*} \
 %(link_shlib) \
 %{!T*: %(link_start) } \
-%(link_target) \
 %(link_os)"
 
 /* Shared libraries are not default.  */
@@ -584,10 +583,6 @@ ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
 %{shared:-G -dy -z text } \
 %{symbolic:-Bsymbolic -G -dy -z text }"
 
-/* Override the default target of the linker.  */
-#define	LINK_TARGET_SPEC \
-  ENDIAN_SELECT("", " --oformat elf32-powerpcle", "")
-
 /* Any specific OS flags.  */
 #define LINK_OS_SPEC "\
 %{mads         : %(link_os_ads)         ; \
@@ -873,7 +868,6 @@ ncrtn.o%s"
   { "endfile_openbsd",		ENDFILE_OPENBSD_SPEC },			\
   { "endfile_default",		ENDFILE_DEFAULT_SPEC },			\
   { "link_shlib",		LINK_SHLIB_SPEC },			\
-  { "link_target",		LINK_TARGET_SPEC },			\
   { "link_start",		LINK_START_SPEC },			\
   { "link_start_ads",		LINK_START_ADS_SPEC },			\
   { "link_start_yellowknife",	LINK_START_YELLOWKNIFE_SPEC },		\
diff --git a/gcc/config/rs6000/sysv4le.h b/gcc/config/rs6000/sysv4le.h
index 7b1d6a1..66ee7ca 100644
--- a/gcc/config/rs6000/sysv4le.h
+++ b/gcc/config/rs6000/sysv4le.h
@@ -25,10 +25,6 @@
 #undef	DEFAULT_ASM_ENDIAN
 #define	DEFAULT_ASM_ENDIAN " -mlittle"
 
-#undef	LINK_TARGET_SPEC
-#define	LINK_TARGET_SPEC \
-  ENDIAN_SELECT(" --oformat elf32-powerpc", "", "")
-
 #undef	MULTILIB_DEFAULTS
 #define	MULTILIB_DEFAULTS { "mlittle", "mcall-sysv" }
 

-- 
Alan Modra
Australia Development Lab, IBM

Re: [RS6000] Don't pass --oformat to ld

[David Edelsohn]

On Tue, Sep 1, 2015 at 9:35 PM, Alan Modra <amodra@gmail.com> wrote:
> bugzilla.redhat.com/show_bug_cgi?id=1255946 shows that gcc built with
> both powerpc64-linux and powerpc64le-linux support passes wrong linker
> options when trying to link in the non-default endian.  A --oformat
> option coming from LINK_TARGET_SPEC is only correct for 32-bit.
>
> It turns out that GNU ld -m options select a particular ld emulation
> (e*.c file in ld build dir) which provides compiled-in scripts or
> selects a script from ldscripts/.  Each of these has an OUTPUT_FORMAT
> statement, which does the same thing as --oformat.  --oformat is
> therefore redundant when using GNU ld built this century, except
> possibly when a user overrides the default ld script with -Wl,-T and
> their script neglects OUTPUT_FORMAT, and it isn't the default output.
> I don't think it's worth fixing this possible use case.
>
> Bootstrap and testing in progress.  OK for mainline assuming all is
> OK?
>
>         * config/rs6000/sysv4le.h (LINK_TARGET_SPEC): Don't define.
>         * config/rs6000/sysv4.h (LINK_TARGET_SPEC): Likewise.
>         (LINK_SPEC, SUBTARGET_EXTRA_SPECS): Delete link_target.

Okay.

Thanks, David

Re: [RS6000] Don't pass --oformat to ld

[Michael Ellerman]

On Wed, 2015-09-02 at 11:05 +0930, Alan Modra wrote:
> bugzilla.redhat.com/show_bug_cgi?id=1255946 shows that gcc built with
> both powerpc64-linux and powerpc64le-linux support passes wrong linker
> options when trying to link in the non-default endian.  A --oformat
> option coming from LINK_TARGET_SPEC is only correct for 32-bit.
> 
> It turns out that GNU ld -m options select a particular ld emulation
> (e*.c file in ld build dir) which provides compiled-in scripts or
> selects a script from ldscripts/.  Each of these has an OUTPUT_FORMAT
> statement, which does the same thing as --oformat.  --oformat is
> therefore redundant when using GNU ld built this century, except
> possibly when a user overrides the default ld script with -Wl,-T and
> their script neglects OUTPUT_FORMAT, and it isn't the default output.
> I don't think it's worth fixing this possible use case.
> 
> Bootstrap and testing in progress.  OK for mainline assuming all is
> OK?
> 
> 	* config/rs6000/sysv4le.h (LINK_TARGET_SPEC): Don't define.
> 	* config/rs6000/sysv4.h (LINK_TARGET_SPEC): Likewise.
> 	(LINK_SPEC, SUBTARGET_EXTRA_SPECS): Delete link_target.

Hi Alan,

If you could please backport this to the gcc-5-branch, that would helpful for
us (kernel folks).

That way we can use the same toolchain for building big or little endian
kernels.

cheers

Re: [RS6000] Don't pass --oformat to ld

[Alan Modra]

On Thu, Sep 24, 2015 at 02:24:25PM +1000, Michael Ellerman wrote:
> On Wed, 2015-09-02 at 11:05 +0930, Alan Modra wrote:
> > bugzilla.redhat.com/show_bug_cgi?id=1255946 shows that gcc built with
> > both powerpc64-linux and powerpc64le-linux support passes wrong linker
> > options when trying to link in the non-default endian.  A --oformat
> > option coming from LINK_TARGET_SPEC is only correct for 32-bit.
> > 
> > It turns out that GNU ld -m options select a particular ld emulation
> > (e*.c file in ld build dir) which provides compiled-in scripts or
> > selects a script from ldscripts/.  Each of these has an OUTPUT_FORMAT
> > statement, which does the same thing as --oformat.  --oformat is
> > therefore redundant when using GNU ld built this century, except
> > possibly when a user overrides the default ld script with -Wl,-T and
> > their script neglects OUTPUT_FORMAT, and it isn't the default output.
> > I don't think it's worth fixing this possible use case.
> > 
> > Bootstrap and testing in progress.  OK for mainline assuming all is
> > OK?
> > 
> > 	* config/rs6000/sysv4le.h (LINK_TARGET_SPEC): Don't define.
> > 	* config/rs6000/sysv4.h (LINK_TARGET_SPEC): Likewise.
> > 	(LINK_SPEC, SUBTARGET_EXTRA_SPECS): Delete link_target.
> 
> Hi Alan,
> 
> If you could please backport this to the gcc-5-branch, that would helpful for
> us (kernel folks).

Bootstrapped and regression tested powerpc64le-linux.  Is this OK for
the branch too, David?

-- 
Alan Modra
Australia Development Lab, IBM

Re: [RS6000] Don't pass --oformat to ld

[David Edelsohn]

On Thu, Sep 24, 2015 at 8:54 AM, Alan Modra <amodra@gmail.com> wrote:
> On Thu, Sep 24, 2015 at 02:24:25PM +1000, Michael Ellerman wrote:
>> On Wed, 2015-09-02 at 11:05 +0930, Alan Modra wrote:
>> > bugzilla.redhat.com/show_bug_cgi?id=1255946 shows that gcc built with
>> > both powerpc64-linux and powerpc64le-linux support passes wrong linker
>> > options when trying to link in the non-default endian.  A --oformat
>> > option coming from LINK_TARGET_SPEC is only correct for 32-bit.
>> >
>> > It turns out that GNU ld -m options select a particular ld emulation
>> > (e*.c file in ld build dir) which provides compiled-in scripts or
>> > selects a script from ldscripts/.  Each of these has an OUTPUT_FORMAT
>> > statement, which does the same thing as --oformat.  --oformat is
>> > therefore redundant when using GNU ld built this century, except
>> > possibly when a user overrides the default ld script with -Wl,-T and
>> > their script neglects OUTPUT_FORMAT, and it isn't the default output.
>> > I don't think it's worth fixing this possible use case.
>> >
>> > Bootstrap and testing in progress.  OK for mainline assuming all is
>> > OK?
>> >
>> >     * config/rs6000/sysv4le.h (LINK_TARGET_SPEC): Don't define.
>> >     * config/rs6000/sysv4.h (LINK_TARGET_SPEC): Likewise.
>> >     (LINK_SPEC, SUBTARGET_EXTRA_SPECS): Delete link_target.
>>
>> Hi Alan,
>>
>> If you could please backport this to the gcc-5-branch, that would helpful for
>> us (kernel folks).
>
> Bootstrapped and regression tested powerpc64le-linux.  Is this OK for
> the branch too, David?

Backporting this bug fix is fine with me.

Thanks!
David