ar and foreign object files

ar is supposed to make archives containing any sort of file, and it
generally does that.  It also tries to make archives suited to target
object files stored.  Some targets have peculiar archives.

In one particular case we get into trouble trying to suit archives to
object files: where the target object file is recognised but that
target doesn't happen to support archives, and the default target has
a special archive format.  For example, we'll get failures on
rs6000-aix if trying to add tekhex objects to a new archive.  What
happens in that the tekhex object is recognised and its target vector
used to create an empty archive, ie. with _bfd_generic_mkarchive and
_bfd_write_archive_contents.  An attempt is then made to open the
newly created archive.  The tekhex target vector does not have a
check_format function to recognise generic archives, nor as it happens
do any of the xcoff or other targets built for rs6000-aix.

It seems to me the simplest fix is to not use any target vector to
create archives where that vector can't also recognise them.  That's
what this patch does, and to reinforce that I've removed target vector
support for creating empty archives from such targets.

bfd/
	* i386msdos.c (i386_msdos_vec): Remove support for creating
	empty archives.
	* ihex.c (ihex_vec): Likewise.
	* srec.c (srec_vec, symbolsrec_vec): Likewise.
	* tekhex.c (tekhex_vec): Likewise.
	* wasm-module.c (wasm_vec): Likewise.
	* ptrace-core.c (core_ptrace_vec): Tidy.
	* targets.c (bfd_target_supports_archives): New inline function.
	* bfd-in2.h: Regenerate.
binutils/
	* ar.c (open_inarch): Don't select a target from the first
	object file that can't read archives.  Set output_filename
	earlier.
	* testsuite/binutils-all/ar.exp (thin_archive_with_nested):
	Don't repeat --thin test using T.
	(foreign_object): New test.
	* testsuite/binutils-all/tek1.obj,
	* testsuite/binutils-all/tek2.obj: New files.

binutils/testsuite/binutils-all/ar.exp

@@ -309,13 +309,11 @@ proc thin_archive_with_nested { bfdtests } {
     if [is_remote host] {
 	set archive artest.a
 	set archive2 artest2.a
-	set archive3 artest3.a
 	set objfile [remote_download host tmpdir/bintest.${obj}]
 	remote_file host delete $archive
     } else {
 	set archive tmpdir/artest.a
 	set archive2 tmpdir/artest2.a
-	set archive3 tmpdir/artest3.a
 	set objfile tmpdir/bintest.${obj}
     }
 
@@ -329,15 +327,7 @@ proc thin_archive_with_nested { bfdtests } {
 
     remote_file build delete tmpdir/artest2.a
 
-    set got [binutils_run $AR "rcT $archive2 ${archive}"]
-    if ![string match "" $got] {
-	fail $testname
-	return
-    }
-
-    remote_file build delete tmpdir/artest3.a
-
-    set got [binutils_run $AR "rc --thin $archive3 ${archive}"]
+    set got [binutils_run $AR "rc --thin $archive2 ${archive}"]
     if ![string match "" $got] {
 	fail $testname
 	return
@@ -357,13 +347,6 @@ proc thin_archive_with_nested { bfdtests } {
 	    fail "$testname ($bfdtest)"
 	    return
 	}
-
-	set exec_output [binutils_run "$base_dir/$bfdtest" "$archive3"]
-	if ![string match "" $exec_output] {
-	    verbose -log $exec_output
-	    fail "$testname ($bfdtest)"
-	    return
-	}
     }
 
     set got [binutils_run $NM "--print-armap $archive"]
@@ -994,6 +977,54 @@ __.LIBDEP*" $got] {
     pass $testname
 }
 
+# Test creation of an archive containing object files not of the same
+# format as the target object files.
+
+proc foreign_object { } {
+    global AR
+    global NM
+    global srcdir
+    global subdir
+
+    set testname "ar foreign object"
+
+    set object1 $srcdir/$subdir/tek1.obj
+    set object2 $srcdir/$subdir/tek2.obj
+    if [is_remote host] {
+	set archive artest.a
+	set object1 [remote_download host $object1]
+	set object2 [remote_download host $object2]
+	remote_file host delete $archive
+    } else {
+	set archive tmpdir/artest.a
+    }
+
+    remote_file build delete tmpdir/artest.a
+
+    set got [binutils_run $AR "rc $archive $object1 $object2"]
+    if ![string match {} $got] {
+	fail $testname
+	return
+    }
+
+    set got [binutils_run $NM $archive]
+    if ![string match {
+tek1.obj:
+*: no symbols
+
+tek2.obj:
+00000001 D _binary_x_end
+00000001 A _binary_x_size
+00000000 D _binary_x_start
+} $got] {
+	fail $testname
+	return
+    }
+
+    pass $testname
+}
+
+
 # Run the tests.
 
 # Only run the bfdtest checks if the programs exist.  Since these
@@ -1030,3 +1061,5 @@ test_add_dependencies
 if { [is_elf_format] && [supports_gnu_unique] } {
     unique_symbol
 }
+
+foreign_object

binutils/testsuite/binutils-all/tek1.obj

@@ -0,0 +1,2 @@
+%47615103000000000000000000000000000000000000000000000000000000000000000
+%0781010

binutils/testsuite/binutils-all/tek2.obj

@@ -0,0 +1,6 @@
+%47615103000000000000000000000000000000000000000000000000000000000000000
+%103E95.data11011
+%1E3FB5.data4F_binary_x_start10
+%1C3735.data4D_binary_x_end11
+%1D3135*ABS*2E_binary_x_size11
+%0781010