Re: PATCH: LDFLAGS handling in V3

[Mark Mitchell <mark at codesourcery dot com>]

Alexandre Oliva wrote:

> Perhaps use -fsysroot instead, and arrange for your script to prefix
> only -f* flags with -Xcompiler, as opposed to handling everything
> except what you know to be special for libtool?  Or maybe extend to
> --* as well, since libtool doesn't handle double-dash arguments?
>  
>>Do you want me to try to skip the -Xcompiler for the options you list?
>  
> Definitely.  Not doing so would certainly break things.

I'm making a pass over my patch queue, trying to get things merged in.
So, I came back to this patch.

To refresh your memory, the point of this patch is that, at present,
putting "--sysroot=..." in LDFLAGS_FOR_TARGET at the top level does not
work, because libtool turns that into -Wl,--sysroot, which means the
driver never sees it, which means that it does not find things like
crt1.o.  We agreed that LDFLAGS_FOR_TARGET was meant to be options to
the driver, and that, therefore, we needed to specifically mark these
options with -Xcompiler when passing them to libtool.

I believe this version addresses the issues you spotted in your review:

http://gcc.gnu.org/ml/libstdc++/2005-10/msg00026.html

Tested on x86_64-unknown-linux-gnu; OK?

Thanks,

-- 
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(650) 331-3385 x713

2005-12-30  Mark Mitchell  <mark@codesourcery.com>

	* libtool-ldflags: New script.

2005-12-30  Mark Mitchell  <mark@codesourcery.com>

	* src/Makefile.am (LTLDFLAGS): New variable.
	(CXXLINK): Use it.
	* libsupc++/Makefile.am (LLDFLAGS): New variable.
	(CXXLINK): Use it.
	* src/Makefile.in: Regenerated.
	* libsupc++/Makefile.in: Likewise.

Index: libtool-ldflags
===================================================================
--- libtool-ldflags	(revision 0)
+++ libtool-ldflags	(revision 0)
@@ -0,0 +1,97 @@
+#! /bin/sh
+
+# Script to translate LDFLAGS into a form suitable for use with libtool.
+
+# Copyright (C) 2005 Free Software Foundation, Inc.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
+# MA 02110-1301, USA. 
+
+# Contributed by CodeSourcery, LLC.
+
+# This script is designed to be used from a Makefile that uses libtool
+# to build libraries as follows: 
+#
+#   LTLDFLAGS = $(shell libtool-ldflags $(LDFLAGS))
+#
+# Then, use (LTLDFLAGS) in place of $(LDFLAGS) in your link line.
+
+# The output of the script.  This string is built up as we process the
+# arguments.
+result=
+
+for arg
+do
+    case $arg in
+	-f*|--*)
+	    # Libtool does not ascribe any special meaning options
+	    # that begin with -f or with a double-dash.  So, it will
+	    # think these options are linker options, and prefix them
+	    # with "-Wl,".  Then, the compiler driver will ignore the
+	    # options.  So, we prefix these options with -Xcompiler to
+	    # make clear to libtool that they are in fact compiler
+	    # options.
+	    result="$result -Xcompiler" 
+	    ;;
+	*)
+	    # We do not want to add -Xcompiler to other options because
+	    # that would prevent libtool itself from recognizing them.
+	    ;;
+    esac
+
+    # If $(LDFLAGS) is (say):
+    #   a "b'c d" e
+    # then the user expects that:
+    #   $(LD) $(LDFLAGS)
+    # will pass three arguments to $(LD):
+    #   1) a
+    #   2) b'c d
+    #   3) e
+    # We must ensure, therefore, that the arguments are appropriately
+    # quoted so that using:
+    #   libtool --mode=link ... $(LTLDFLAGS)
+    # will result in the same number of arguments being passed to
+    # libtool.   In other words, when this script was invoked, the shell 
+    # removed one level of quoting, present in $(LDFLAGS); we have to put 
+    # it back.
+
+    # Quote any embedded single quotes.
+    case $arg in
+	*"'"*)
+	    # The following command creates the script:
+	    #   1s,^X,,;s|'|'"'"'|g
+	    # which removes a leading X, and then quotes and embedded single
+	    # quotes.
+	    sed_script="1s,^X,,;s|'|'\"'\"'|g"
+	    # Add a leading "X" so that if $arg starts with a dash,
+	    # the echo command will not try to interpret the argument
+	    # as a command-line option.
+	    arg="X$arg"
+	    # Generate the quoted string.
+	    quoted_arg=`echo "$arg" | sed -e "$sed_script"`
+	    ;;
+	*)
+	    quoted_arg=$arg
+	    ;;
+    esac
+    # Surround the entire argument with single quotes.
+    quoted_arg="'"$quoted_arg"'" 
+
+    # Add it to the string.
+    result="$result $quoted_arg"
+done
+
+# Output the string we have built up.
+echo "$result"

Property changes on: libtool-ldflags
___________________________________________________________________
Name: svn:executable
   + *

Index: libstdc++-v3/src/Makefile.am
===================================================================
--- libstdc++-v3/src/Makefile.am	(revision 109078)
+++ libstdc++-v3/src/Makefile.am	(working copy)
@@ -226,6 +226,8 @@ AM_CXXFLAGS = \
 LTCXXCOMPILE = $(LIBTOOL) --tag CXX --mode=compile $(CXX) $(INCLUDES) \
 	       $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) 
 
+LTLDFLAGS = $(shell $(top_srcdir)/../libtool-ldflags $(LDFLAGS))
+
 # 3) We'd have a problem when building the shared libstdc++ object if
 # the rules automake generates would be used.  We cannot allow g++ to
 # be used since this would add -lstdc++ to the link line which of
@@ -233,7 +235,7 @@ LTCXXCOMPILE = $(LIBTOOL) --tag CXX --mo
 # directory to configure libstdc++-v3 to use gcc as the C++
 # compilation driver.
 CXXLINK = $(LIBTOOL) --tag CXX --mode=link $(CXX) \
-	  $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LDFLAGS) -o $@
+	  $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LTLDFLAGS) -o $@
 
 
 # Added bits to build debug library.
Index: libstdc++-v3/libsupc++/Makefile.am
===================================================================
--- libstdc++-v3/libsupc++/Makefile.am	(revision 109078)
+++ libstdc++-v3/libsupc++/Makefile.am	(working copy)
@@ -139,6 +139,8 @@ LTCXXCOMPILE = $(LIBTOOL) --tag CXX --ta
 	       --mode=compile $(CXX) $(TOPLEVEL_INCLUDES) \
 	       $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CXXFLAGS) $(CXXFLAGS) 
 
+LTLDFLAGS = $(shell $(top_srcdir)/../libtool-ldflags $(LDFLAGS))
+
 # 3) We'd have a problem when building the shared libstdc++ object if
 # the rules automake generates would be used.  We cannot allow g++ to
 # be used since this would add -lstdc++ to the link line which of
@@ -147,7 +149,7 @@ LTCXXCOMPILE = $(LIBTOOL) --tag CXX --ta
 # compilation driver.
 CXXLINK = $(LIBTOOL) --tag CXX --tag disable-shared \
 	  --mode=link $(CXX) \
-	  $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LDFLAGS) -o $@
+	  $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LTLDFLAGS) -o $@
 
 # We have to have rules modified from the default to counteract SUN make
 # prepending each of $(glibcxxinstall_HEADERS) with VPATH below.