[PATCH] gcc configure's determination of ld and as

[Alan Modra <amodra at bigpond dot net dot au>]

Today, I found to my dismay that using --with-ld=path_to_ld when
configuring gcc leads to a compiler that effectively ignores -B paths
when searching for ld.  This meant that binutils "make check" on my
powerpc64-linux box has been testing an installed linker for some of the
ld tests, rather than the newly built one.  So I've missed seeing ld
regressions.

Now, the reason I use --with-ld is that I have left /usr/bin/ld
unchanged from my original Linux installation, and build bleeding edge
toolchains installed in /usr/local/.  My path selects the /usr/local
versions, but gcc configure goes looking in /usr/bin before checking
my PATH environment var.  Which is annoying because a number of
configure tests fail if /usr/bin/ld is used, and plain wrong because the
newly built compiler will use /usr/local/bin/ld before /usr/bin/ld.
Apparently this is because some gcc targets used to specify an
MD_EXEC_PREFIX of "/usr/bin/".  So I decided to fix this sad piece of
configure hackery by not looking at (an out of date) list of "all known
MD_EXEC_PREFIX values", but instead discover the actual MD_EXEC_PREFIX
from tm files.

	* configure.ac (gcc_cv_as, gcc_cv_ld): Examine MD_EXEC_PREFIX in
	tm files to determine compiler search path.  Kill code duplication.

Tested powerpc-linux.  OK to install?  How about 4.0 and 3.4 too?

diff -urp -xCVS -x'*~' -x'.#*' gcc-virgin/gcc/configure.ac gcc-current/gcc/configure.ac
--- gcc-virgin/gcc/configure.ac	2005-06-02 18:15:26.000000000 +0930
+++ gcc-current/gcc/configure.ac	2005-06-02 18:46:31.000000000 +0930
@@ -1776,28 +1776,48 @@ fi
 
 gcc_version=`cat $srcdir/BASE-VER`
 
-if test "x$gcc_cv_as" = x; then
-	# Search the same directories that the installed compiler will
-	# search.  Else we may find the wrong assembler and lose.  If we
-	# do not find a suitable assembler binary, then try the user's
-	# path.
-	#
-	# Also note we have to check MD_EXEC_PREFIX before checking the
-	# user's path.  Unfortunately, there is no good way to get at the
-	# value of MD_EXEC_PREFIX here.  So we do a brute force search
-	# through all the known MD_EXEC_PREFIX values.  Ugh.  This needs
-	# to be fixed as part of the make/configure rewrite too.
-
-	if test "x$exec_prefix" = xNONE; then
-		if test "x$prefix" = xNONE; then
-			test_prefix=/usr/local
-		else
-			test_prefix=$prefix
-		fi
+# When searching for the assembler or linker, search the same directories
+# that the installed compiler will search.  Else we may find the wrong
+# assembler or linker and lose.  If we do not find a suitable binary,
+# then try the user's path.
+#
+# Also note we have to check MD_EXEC_PREFIX before checking the user's path.
+if test "x$exec_prefix" = xNONE; then
+	if test "x$prefix" = xNONE; then
+		test_prefix=/usr/local
 	else
-		test_prefix=$exec_prefix
+		test_prefix=$prefix
 	fi
+else
+	test_prefix=$exec_prefix
+fi
+
+if test x$host = x$build; then
+    test_dirs="$test_prefix/libexec/gcc/$target_noncanonical/$gcc_version \
+	       $test_prefix/libexec/gcc/$target_noncanonical \
+	       /usr/lib/gcc/$target_noncanonical/$gcc_version \
+	       /usr/lib/gcc/$target_noncanonical \
+	       $test_prefix/$target_noncanonical/bin/$target_noncanonical/$gcc_version \
+	       $test_prefix/$target_noncanonical/bin"
+else
+    test_dirs=
+fi
 
+if test x$build = x$target; then
+# Rummage through tm_files looking for MD_EXEC_PREFIX
+    md_dirs=
+    for f in ${tm_file_list}; do
+	if test -f $f; then
+	    if grep '^#[ 	]*undef[ 	]*MD_EXEC_PREFIX' $f > /dev/null; then
+		md_dirs=
+	    fi
+	    md_dirs="$md_dirs "`sed -n -e 's@^#[ 	]*define[ 	]*MD_EXEC_PREFIX[ 	]*"\(.*\)/"@\1@p' < $f`
+	fi
+    done
+    test_dirs="$test_dirs $md_dirs"
+fi
+
+if test "x$gcc_cv_as" = x; then
 	# If the loop below does not find an assembler, then use whatever
 	# one we can find in the users's path.  We are looking for a
 	# ${build} -> ${target} assembler.
@@ -1809,31 +1829,6 @@ if test "x$gcc_cv_as" = x; then
 		gcc_cv_as=`echo as | sed "${program_transform_name}"`$build_exeext
 	fi
 
-	if test x$host = x$build; then
-	    test_dirs="$test_prefix/libexec/gcc/$target_noncanonical/$gcc_version \
-		       $test_prefix/libexec/gcc/$target_noncanonical \
-		       /usr/lib/gcc/$target_noncanonical/$gcc_version \
-		       /usr/lib/gcc/$target_noncanonical \
-		       $test_prefix/$target_noncanonical/bin/$target_noncanonical/$gcc_version \
-		       $test_prefix/$target_noncanonical/bin"
-	else
-	    test_dirs=
-	fi
-
-	if test x$build = x$target; then
-	    test_dirs="$test_dirs \
-		   /usr/libexec \
-		   /usr/ccs/gcc \
-		   /usr/ccs/bin \
-		   /udk/usr/ccs/bin \
-		   /bsd43/usr/lib/cmplrs/cc \
-		   /usr/cross64/usr/bin \
-		   /usr/lib/cmplrs/cc \
-		   /sysv/usr/lib/cmplrs/cc \
-		   /svr4/usr/lib/cmplrs/cc \
-		   /usr/bin"
-	fi
-
 	for dir in $test_dirs; do
 		if test -x $dir/as$build_exeext; then
 			gcc_cv_as=$dir/as$build_exeext
@@ -1904,17 +1899,6 @@ elif test -x "$LD" && test x$host = x$ta
 fi
 
 if test "x$gcc_cv_ld" = x; then
-	# Search the same directories that the installed compiler will
-	# search.  Else we may find the wrong linker and lose.  If we
-	# do not find a suitable linker binary, then try the user's
-	# path.
-	#
-	# Also note we have to check MD_EXEC_PREFIX before checking the
-	# user's path.  Unfortunately, there is no good way to get at the
-	# value of MD_EXEC_PREFIX here.  So we do a brute force search
-	# through all the known MD_EXEC_PREFIX values.  Ugh.  This needs
-	# to be fixed as part of the make/configure rewrite too.
-
 	if test "x$exec_prefix" = xNONE; then
 		if test "x$prefix" = xNONE; then
 			test_prefix=/usr/local
@@ -1936,31 +1920,6 @@ if test "x$gcc_cv_ld" = x; then
 		gcc_cv_ld=`echo ld | sed "${program_transform_name}"`$build_exeext
 	fi
 
-	if test x$host = x$build; then
-	    test_dirs="$test_prefix/libexec/gcc/$target_noncanonical/$gcc_version \
-		       $test_prefix/libexec/gcc/$target_noncanonical \
-		       /usr/lib/gcc/$target_noncanonical/$gcc_version \
-		       /usr/lib/gcc/$target_noncanonical \
-		       $test_prefix/$target_noncanonical/bin/$target_noncanonical/$gcc_version \
-		       $test_prefix/$target_noncanonical/bin"
-	else
-	    test_dirs=
-	fi
-
-	if test x$build = x$target; then
-	    test_dirs="$test_dirs \
-		   /usr/libexec \
-		   /usr/ccs/gcc \
-		   /usr/ccs/bin \
-		   /udk/usr/ccs/bin \
-		   /bsd43/usr/lib/cmplrs/cc \
-		   /usr/cross64/usr/bin \
-		   /usr/lib/cmplrs/cc \
-		   /sysv/usr/lib/cmplrs/cc \
-		   /svr4/usr/lib/cmplrs/cc \
-		   /usr/bin"
-	fi
-
 	for dir in $test_dirs; do
 		if test -x $dir/ld$build_exeext; then
 			gcc_cv_ld=$dir/ld$build_exeext

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre