prefer in-tree as and ld over pre-installed ones

[Alexandre Oliva <aoliva at redhat dot com>]

If you happen to have a pre-installed assembler or linker in the
compiler search path, or if top-level configure happens to find an
assembler or linker for the host (if cross building) or a linker for
the target (we missed the assembler for the target), gcc would use
that for the configure tests, even when it knows we're building an
assembler and/or a linker alongside itself, that it's going to use at
run time.  That's bad.

I fixed the most visible part of this problem some time ago, but only
now did I finally get the logic in such a way that I think it actually
makes sense.  So I'm checking this in.

It works fine for natives, crosses and Canadians, with the expected
semantics, and gets the compiler to prefer what's in the build tree
regardless of what the top-level might have found already installed at
the time it ran.

I'm checking this in.

Index: gcc/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	* configure.ac (gcc_cv_ld): Prefer in-tree ld over whatever the
	top-level detects, except when in-tree ld is being cross-built.
	(gcc_cv_as): Likewise for as.  Use AS_FOR_TARGET otherwise, and
	then AS only if target is host.
	* configure: Rebuilt.

Index: gcc/configure.ac
===================================================================
RCS file: /cvs/gcc/gcc/gcc/configure.ac,v
retrieving revision 2.37
diff -u -p -r2.37 configure.ac
--- gcc/configure.ac 24 May 2004 10:50:33 -0000 2.37
+++ gcc/configure.ac 25 May 2004 19:40:40 -0000
@@ -1689,14 +1689,15 @@ gcc_cv_gas_minor_version=
 gcc_cv_as_gas_srcdir=`echo $srcdir | sed -e 's,/gcc$,,'`/gas
 if test -x "$DEFAULT_ASSEMBLER"; then
 	gcc_cv_as="$DEFAULT_ASSEMBLER"
-elif test -x "$AS"; then
-	gcc_cv_as="$AS"
 elif test -x as$host_exeext; then
 	# Build using assembler in the current directory.
 	gcc_cv_as=./as$host_exeext
 elif test -f $gcc_cv_as_gas_srcdir/configure.in \
-     && test -f ../gas/Makefile; then
-  # Single tree build which includes gas.
+     && test -f ../gas/Makefile \
+     && test x$build = x$host; then
+  # Single tree build which includes gas.  We want to prefer it
+  # over whatever linker top-level may have detected, since
+  # we'll use what we're building after installation anyway.
   in_tree_gas=yes
   _gcc_COMPUTE_GAS_VERSION
   rm -f as$host_exeext
@@ -1708,6 +1709,11 @@ elif test -f $gcc_cv_as_gas_srcdir/confi
   then
     in_tree_gas_is_elf=yes
   fi
+m4_pattern_allow([AS_FOR_TARGET])dnl
+elif test -x "$AS_FOR_TARGET"; then
+        gcc_cv_as="$AS_FOR_TARGET"
+elif test -x "$AS" && test x$host = x$target; then
+	gcc_cv_as="$AS"
 fi
 
 if test "x$gcc_cv_as" = x; then
@@ -1794,16 +1800,15 @@ gcc_cv_ld_gld_srcdir=`echo $srcdir | sed
 gcc_cv_ld_bfd_srcdir=`echo $srcdir | sed -e 's,/gcc$,,'`/bfd
 if test -x "$DEFAULT_LINKER"; then
 	gcc_cv_ld="$DEFAULT_LINKER"
-elif test -x "$LD_FOR_TARGET"; then
-        gcc_cv_ld="$LD_FOR_TARGET"
-elif test -x "$LD" && test x$host = x$target; then
-	gcc_cv_ld="$LD"
 elif test -x collect-ld$host_exeext; then
 	# Build using linker in the current directory.
 	gcc_cv_ld=./collect-ld$host_exeext
 elif test -f $gcc_cv_ld_gld_srcdir/configure.in \
-     && test -f ../ld/Makefile; then
-	# Single tree build which includes ld.
+     && test -f ../ld/Makefile \
+     && test x$build = x$host; then
+	# Single tree build which includes ld.  We want to prefer it
+	# over whatever linker top-level may have detected, since
+	# we'll use what we're building after installation anyway.
 	in_tree_ld=yes
 	in_tree_ld_is_elf=no
 	if (grep 'EMUL = .*elf' ../ld/Makefile \
@@ -1826,6 +1831,10 @@ changequote([,])dnl
 	rm -f collect-ld$host_exeext
 	$symbolic_link ../ld/ld-new$host_exeext collect-ld$host_exeext \
 		2>/dev/null
+elif test -x "$LD_FOR_TARGET"; then
+        gcc_cv_ld="$LD_FOR_TARGET"
+elif test -x "$LD" && test x$host = x$target; then
+	gcc_cv_ld="$LD"
 fi
 
 if test "x$gcc_cv_ld" = x; then

-- 
Alexandre Oliva             http://www.ic.unicamp.br/~oliva/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}