Patchwork [2/2] Add gcc-ar, gcc-ranlib, gcc-ld wrappers v2

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Submitter Andi Kleen
Date Oct. 29, 2010, 6:14 p.m.
Message ID <1288376060-12168-2-git-send-email-andi@firstfloor.org>
Download mbox | patch
Permalink /patch/69620/
State New
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Comments

Andi Kleen - Oct. 29, 2010, 6:14 p.m.
From: Andi Kleen <ak@linux.intel.com>

[Updated version, see changelog below. I decided to drop
gcc-ld for now because that one seemed to be problematic
and is only needed for some specific project. I guess I can
keep it separate.]

Earlier review resulted in a request for having gcc-... wrappers
to handle the LTO symbol tables for ranlib/ar. This is needed for slim
lto files, because these tools cannot read the symbol table
otherwise. Essentially they just call binutils with
the LTO plugin specified.

Other compilers with LTO support tend to have similar tools.

This patch implements those wrappers.

The wrappers are also needed for a LTO slim of gcc. Right now
they have to be manually specified for that.

The wrappers require uptodate binutils (the upcoming release)
with plugin support enabled.  There is currently no autoconf
support to detect that. The wrappers query the gcc driver
in an attempt to handle cross compilation and so naming everywhere

v2: drop gcc-ld for now. support relocated installation trees.

gcc/lto/

2010-10-26  Andi Kleen  <ak@linux.intel.com>

	* Make-lang.in (AR_INSTALL_NAME, RANLIB_INSTALL_NAME, LTO_WRAPPERS):
	Add.
	(lto.all.cross, lto.start.cross): Add dependency to LTO_WRAPPERS.
	(lto.install.common): Install wrappers.
	(lto.mostlyclean): Clean wrappers.
	* gcc-ar, gcc-ranlib.in: Add.

gcc/

2010-10-26  Andi Kleen  <ak@linux.intel.com>

	* doc/invoke.texi (gcc-ar, gcc-ranlib): Document.
---
 gcc/doc/invoke.texi  |    3 +++
 gcc/lto/Make-lang.in |   17 +++++++++++++++--
 gcc/lto/gcc-ar       |    7 +++++++
 gcc/lto/gcc-ranlib   |    7 +++++++
 4 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100755 gcc/lto/gcc-ar
 create mode 100644 gcc/lto/gcc-ranlib
H.J. Lu - Oct. 29, 2010, 6:19 p.m.
On Fri, Oct 29, 2010 at 11:14 AM, Andi Kleen <andi@firstfloor.org> wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> [Updated version, see changelog below. I decided to drop
> gcc-ld for now because that one seemed to be problematic
> and is only needed for some specific project. I guess I can
> keep it separate.]
>
> Earlier review resulted in a request for having gcc-... wrappers
> to handle the LTO symbol tables for ranlib/ar. This is needed for slim
> lto files, because these tools cannot read the symbol table
> otherwise. Essentially they just call binutils with
> the LTO plugin specified.
>
> Other compilers with LTO support tend to have similar tools.
>
> This patch implements those wrappers.
>
> The wrappers are also needed for a LTO slim of gcc. Right now
> they have to be manually specified for that.
>
> The wrappers require uptodate binutils (the upcoming release)
> with plugin support enabled.  There is currently no autoconf
> support to detect that. The wrappers query the gcc driver
> in an attempt to handle cross compilation and so naming everywhere
>
> v2: drop gcc-ld for now. support relocated installation trees.
>
> gcc/lto/
>
> 2010-10-26  Andi Kleen  <ak@linux.intel.com>
>
>        * Make-lang.in (AR_INSTALL_NAME, RANLIB_INSTALL_NAME, LTO_WRAPPERS):
>        Add.
>        (lto.all.cross, lto.start.cross): Add dependency to LTO_WRAPPERS.
>        (lto.install.common): Install wrappers.
>        (lto.mostlyclean): Clean wrappers.
>        * gcc-ar, gcc-ranlib.in: Add.
>
> gcc/
>
> 2010-10-26  Andi Kleen  <ak@linux.intel.com>
>
>        * doc/invoke.texi (gcc-ar, gcc-ranlib): Document.

> diff --git a/gcc/lto/gcc-ranlib b/gcc/lto/gcc-ranlib
> new file mode 100644
> index 0000000..467d593
> --- /dev/null
> +++ b/gcc/lto/gcc-ranlib
> @@ -0,0 +1,7 @@
> +#!/bin/sh
> +# wrapper for ranlib with GCC LTO support
> +
> +BASE=`readlink -f $0`
> +BINDIR=`dirname $BASE`
> +AR=${AR:-`$BINDIR/gcc -print-prog-name=ar`}
> +exec $AR -s --plugin `$GCC_BINDIR/gcc -print-lto-plugin` "$@"
> --
> 1.7.1
>

Did you mean

exec $AR -s --plugin `$BINDIR/gcc -print-lto-plugin` "$@"

Also does it work in the GCC build directory?
Andi Kleen - Oct. 29, 2010, 6:41 p.m.
> 
> exec $AR -s --plugin `$BINDIR/gcc -print-lto-plugin` "$@"

Yes you're right of course. Fixed.

Weird my test worked. Maybe the variable was already set.

> Also does it work in the GCC build directory?

Right now for that you have to override AR, it doesn't know
about xgcc. Ok I guess it should. Will fix that too.

-Andi
H.J. Lu - Oct. 29, 2010, 6:46 p.m.
On Fri, Oct 29, 2010 at 11:41 AM, Andi Kleen <andi@firstfloor.org> wrote:
>>
>> exec $AR -s --plugin `$BINDIR/gcc -print-lto-plugin` "$@"
>
> Yes you're right of course. Fixed.

gcc-ranlib have the same problem. Don't we also need "gcc -nm"?
Paolo Bonzini - Oct. 29, 2010, 8:22 p.m.
On 10/29/2010 08:14 PM, Andi Kleen wrote:
> +ifeq ($(enable_plugin),yes)
> +	$(INSTALL_SCRIPT) lto/gcc-ar $(DESTDIR)$(bindir)/$(AR_INSTALL_NAME)
> +	$(INSTALL_SCRIPT) lto/gcc-ranlib $(DESTDIR)$(bindir)/$(RANLIB_INSTALL_NAME)
> +endif

In addition to what pointed out by Joseph (including the preference for 
a C implementation), this is also wrong for cross-compiling.  It needs 
to be installed as $(DESTDIR)$(gcc_tooldir)/bin/$(AR_INSTALL_NAME) in 
that case.

>> exec $AR --plugin `$BINDIR/gcc -print-lto-plugin` "$@"

quotes around $BINDIR, as Ralf suggested, but also around the backticks 
and $AR.  For portability that needs to be

LTOPLUGIN=`"$BINDIR"/gcc -print-lto-plugin`
exec "$AR" --plugin "$LTOPLUGIN" "$@"

Paolo
Joseph S. Myers - Oct. 29, 2010, 9:51 p.m.
On Fri, 29 Oct 2010, Paolo Bonzini wrote:

> On 10/29/2010 08:14 PM, Andi Kleen wrote:
> > +ifeq ($(enable_plugin),yes)
> > +	$(INSTALL_SCRIPT) lto/gcc-ar $(DESTDIR)$(bindir)/$(AR_INSTALL_NAME)
> > +	$(INSTALL_SCRIPT) lto/gcc-ranlib
> > $(DESTDIR)$(bindir)/$(RANLIB_INSTALL_NAME)
> > +endif
> 
> In addition to what pointed out by Joseph (including the preference for a C
> implementation), this is also wrong for cross-compiling.  It needs to be
> installed as $(DESTDIR)$(gcc_tooldir)/bin/$(AR_INSTALL_NAME) in that case.

I thought the point was to install a binary for users to use, not for 
internal use by other programs - that is, something in bindir, which is 
the place for user binaries, not gcc_tooldir/bin, which is the place for 
internal binaries.  AR_INSTALL_NAME is the transformed name, suitable for 
use in bindir.  (The copies of "gcc" and "g++" in gcc_tooldir/bin are 
actually completely useless, as they don't know how to locate the other 
parts of the installation so fail trying to exec cc1 or cc1plus; the 
driver is only relocatable as long as it's run from bindir.  GNU ld, 
however, *does* know how to locate its ldscripts directory when run from 
either location.)
Paolo Bonzini - Oct. 29, 2010, 10:31 p.m.
On 10/29/2010 11:51 PM, Joseph S. Myers wrote:
> On Fri, 29 Oct 2010, Paolo Bonzini wrote:
>
>> On 10/29/2010 08:14 PM, Andi Kleen wrote:
>>> +ifeq ($(enable_plugin),yes)
>>> +	$(INSTALL_SCRIPT) lto/gcc-ar $(DESTDIR)$(bindir)/$(AR_INSTALL_NAME)
>>> +	$(INSTALL_SCRIPT) lto/gcc-ranlib
>>> $(DESTDIR)$(bindir)/$(RANLIB_INSTALL_NAME)
>>> +endif
>>
>> In addition to what pointed out by Joseph (including the preference for a C
>> implementation), this is also wrong for cross-compiling.  It needs to be
>> installed as $(DESTDIR)$(gcc_tooldir)/bin/$(AR_INSTALL_NAME) in that case.
>
> I thought the point was to install a binary for users to use, not for
> internal use by other programs - that is, something in bindir, which is
> the place for user binaries, not gcc_tooldir/bin, which is the place for
> internal binaries.  AR_INSTALL_NAME is the transformed name, suitable for
> use in bindir.

You're right.  I was confused by gcc-ar using $BINDIR/gcc to locate gcc 
(which doesn't work for cross-compiling).

Paolo
Ralf Wildenhues - Oct. 30, 2010, 6:32 a.m.
* Paolo Bonzini wrote on Fri, Oct 29, 2010 at 10:22:50PM CEST:
> >>exec $AR --plugin `$BINDIR/gcc -print-lto-plugin` "$@"
> 
> quotes around $BINDIR, as Ralf suggested, but also around the
> backticks and $AR.  For portability that needs to be
> 
> LTOPLUGIN=`"$BINDIR"/gcc -print-lto-plugin`
> exec "$AR" --plugin "$LTOPLUGIN" "$@"

JFTR: can $AR be 'ar -X32_64' (on AIX) at this point?

Cheers,
Ralf
Andi Kleen - Oct. 30, 2010, 7:46 a.m.
On Sat, Oct 30, 2010 at 08:32:21AM +0200, Ralf Wildenhues wrote:
> * Paolo Bonzini wrote on Fri, Oct 29, 2010 at 10:22:50PM CEST:
> > >>exec $AR --plugin `$BINDIR/gcc -print-lto-plugin` "$@"
> > 
> > quotes around $BINDIR, as Ralf suggested, but also around the
> > backticks and $AR.  For portability that needs to be
> > 
> > LTOPLUGIN=`"$BINDIR"/gcc -print-lto-plugin`
> > exec "$AR" --plugin "$LTOPLUGIN" "$@"
> 
> JFTR: can $AR be 'ar -X32_64' (on AIX) at this point?

Does AIX support binutils and LTO? This all only works with GNU binutils 
and LTO support anyways.

Anyways my trend is to go to shelve the patch (or rather keep
the wrappers as a separate package) because the reception has been too 
negative.  I guess it won't be too difficult to download it separately
for people who need it.

-Andi
Paolo Bonzini - Oct. 30, 2010, 8:01 a.m.
On 10/30/2010 09:46 AM, Andi Kleen wrote:
> On Sat, Oct 30, 2010 at 08:32:21AM +0200, Ralf Wildenhues wrote:
>> * Paolo Bonzini wrote on Fri, Oct 29, 2010 at 10:22:50PM CEST:
>>>>> exec $AR --plugin `$BINDIR/gcc -print-lto-plugin` "$@"
>>>
>>> quotes around $BINDIR, as Ralf suggested, but also around the
>>> backticks and $AR.  For portability that needs to be
>>>
>>> LTOPLUGIN=`"$BINDIR"/gcc -print-lto-plugin`
>>> exec "$AR" --plugin "$LTOPLUGIN" "$@"
>>
>> JFTR: can $AR be 'ar -X32_64' (on AIX) at this point?
>
> Does AIX support binutils and LTO? This all only works with GNU binutils
> and LTO support anyways.
>
> Anyways my trend is to go to shelve the patch (or rather keep
> the wrappers as a separate package) because the reception has been too
> negative.  I guess it won't be too difficult to download it separately
> for people who need it.

I would still like that patch 1/2 goes in, please.

Paolo
Andi Kleen - Oct. 30, 2010, 9:22 a.m.
> I would still like that patch 1/2 goes in, please.

If someone approves it I can commit it.

-Andi

Patch

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d6784ad..5cae0e4 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -7565,6 +7565,9 @@  be exported, it is possible to combine @option{-flto} and
 interprocedural optimizers to use more aggressive assumptions which
 may lead to improved optimization opportunities.
 
+In some cases you may need to use the @command{gcc-ar} and 
+@command{gcc-ranlib} commands to manage ar files of LTO objects. 
+
 Regarding portability: the current implementation of LTO makes no
 attempt at generating bytecode that can be ported between different
 types of hosts.  The bytecode files are versioned and there is a
diff --git a/gcc/lto/Make-lang.in b/gcc/lto/Make-lang.in
index 2dc6409..56f126d 100644
--- a/gcc/lto/Make-lang.in
+++ b/gcc/lto/Make-lang.in
@@ -28,16 +28,29 @@  LTO_H = lto/lto.h $(HASHTAB_H)
 LINKER_PLUGIN_API_H = $(srcdir)/../include/plugin-api.h
 LTO_TREE_H = lto/lto-tree.h $(LINKER_PLUGIN_API_H)
 
+AR_INSTALL_NAME := $(shell echo gcc-ar|sed '$(program_transform_name)')
+RANLIB_INSTALL_NAME := $(shell echo gcc-ranlib|sed '$(program_transform_name)')
+
+ifeq ($(enable_plugin),yes)
+LTO_WRAPPERS = lto/gcc-ar lto/gcc-ranlib
+else
+LTO_WRAPPERS =
+endif
 
 # Rules
 
 # These hooks are used by the main GCC Makefile.  Consult that
 # Makefile for documentation.
-lto.all.cross: $(LTO_EXE)
-lto.start.encap: $(LTO_EXE)
+lto.all.cross: $(LTO_EXE) $(LTO_WRAPPERS)
+lto.start.encap: $(LTO_EXE) $(LTO_WRAPPERS)
 lto.rest.encap:
 lto.tags:
 lto.install-common:
+ifeq ($(enable_plugin),yes)
+	$(INSTALL_SCRIPT) lto/gcc-ar $(DESTDIR)$(bindir)/$(AR_INSTALL_NAME)
+	$(INSTALL_SCRIPT) lto/gcc-ranlib $(DESTDIR)$(bindir)/$(RANLIB_INSTALL_NAME)
+endif
+
 lto.install-man:
 lto.install-info:
 lto.dvi:
diff --git a/gcc/lto/gcc-ar b/gcc/lto/gcc-ar
new file mode 100755
index 0000000..4a49e23
--- /dev/null
+++ b/gcc/lto/gcc-ar
@@ -0,0 +1,7 @@ 
+#!/bin/sh
+# wrapper for ar with GCC LTO support
+
+BASE=`readlink -f $0`
+BINDIR=`dirname $BASE`
+AR=${AR:-`$BINDIR/gcc -print-prog-name=ar`}
+exec $AR --plugin `$GCC_BINDIR/gcc -print-lto-plugin` "$@"
diff --git a/gcc/lto/gcc-ranlib b/gcc/lto/gcc-ranlib
new file mode 100644
index 0000000..467d593
--- /dev/null
+++ b/gcc/lto/gcc-ranlib
@@ -0,0 +1,7 @@ 
+#!/bin/sh
+# wrapper for ranlib with GCC LTO support
+
+BASE=`readlink -f $0`
+BINDIR=`dirname $BASE`
+AR=${AR:-`$BINDIR/gcc -print-prog-name=ar`}
+exec $AR -s --plugin `$GCC_BINDIR/gcc -print-lto-plugin` "$@"