fix gas abort on lone .loc_mark_labels

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

Two bug fixes and some tidying, prompted by
http://sourceware.org/ml/gdb-patches/2008-04/msg00130.html

	* dwarf2dbg.c (dwarf2_emit_insn): Simplify test before dwarf2_where
	call.  Delete out of date comment.
No functional change here.

	(dwarf2_consume_line_info): Always clear dwarf2_loc_directive_seen.
All uses of this flag are with a test of debug_type, so keeping the flag
when DEBUG_DWARF2 is unnecessary.

	(dwarf2_emit_label): Don't emit unless there has been a previous
	.file or we are outputting assembler generated debug.
This fixes a later abort in out_debug_info.
	dwarf2_consume_line_info after emitting line info, not before.
Fixes loss of basic block flag.

	(out_debug_info): Simplify files_in_use test.

Index: gas/dwarf2dbg.c
===================================================================
RCS file: /cvs/src/src/gas/dwarf2dbg.c,v
retrieving revision 1.95
diff -u -p -r1.95 dwarf2dbg.c
--- gas/dwarf2dbg.c	9 Jan 2008 17:30:58 -0000	1.95
+++ gas/dwarf2dbg.c	7 Apr 2008 23:30:11 -0000
@@ -365,19 +365,10 @@ dwarf2_emit_insn (int size)
 {
   struct dwarf2_line_info loc;
 
-  if (dwarf2_loc_directive_seen)
-    {
-      /* Use the last location established by a .loc directive, not
-	 the value returned by dwarf2_where().  That calls as_where()
-	 which will return either the logical input file name (foo.c)
-	or the physical input file name (foo.s) and not the file name
-	specified in the most recent .loc directive (eg foo.h).  */
-      loc = current;
-    }
-  else if (debug_type != DEBUG_DWARF2)
+  if (!dwarf2_loc_directive_seen && debug_type != DEBUG_DWARF2)
     return;
-  else
-    dwarf2_where (&loc);
+
+  dwarf2_where (&loc);
 
   dwarf2_gen_line_info (frag_now_fix () - size, &loc);
   dwarf2_consume_line_info ();
@@ -393,8 +384,7 @@ dwarf2_consume_line_info (void)
 {
   /* Unless we generate DWARF2 debugging information for each
      assembler line, we only emit one line symbol for one LOC.  */
-  if (debug_type != DEBUG_DWARF2)
-    dwarf2_loc_directive_seen = FALSE;
+  dwarf2_loc_directive_seen = FALSE;
 
   current.flags &= ~(DWARF2_FLAG_BASIC_BLOCK
 		     | DWARF2_FLAG_PROLOGUE_END
@@ -415,16 +405,15 @@ dwarf2_emit_label (symbolS *label)
     return;
   if (!(bfd_get_section_flags (stdoutput, now_seg) & SEC_CODE))
     return;
-  
-  if (debug_type == DEBUG_DWARF2)
-    dwarf2_where (&loc);
-  else
-    loc = current;
+  if (files_in_use == 0 && debug_type != DEBUG_DWARF2)
+    return;
+
+  dwarf2_where (&loc);
 
   loc.flags |= DWARF2_FLAG_BASIC_BLOCK;
 
-  dwarf2_consume_line_info ();
   dwarf2_gen_line_info_1 (label, &loc);
+  dwarf2_consume_line_info ();
 }
 
 /* Get a .debug_line file number for FILENAME.  If NUM is nonzero,
@@ -1671,7 +1660,7 @@ out_debug_info (segT info_seg, segT abbr
      on the command line, so assume files[1] is the main input file.
      We're not supposed to get called unless at least one line number
      entry was emitted, so this should always be defined.  */
-  if (!files || files_in_use < 1)
+  if (files_in_use == 0)
     abort ();
   if (files[1].dir)
     {

-- 
Alan Modra
Australia Development Lab, IBM