Index: gcc/final.c
===================================================================
--- gcc/final.c	(revision 106485)
+++ gcc/final.c	(working copy)
@@ -129,6 +129,8 @@
 static rtx debug_insn;
 rtx current_output_insn;
 
+int current_start_basic_block = 0;
+
 /* Line number of last NOTE.  */
 static int last_linenum;
 
@@ -1744,6 +1746,7 @@
 	  else
 	    *seen |= SEEN_BB;
 
+	  current_start_basic_block = 1;
 	  break;
 
 	case NOTE_INSN_EH_REGION_BEG:
@@ -2071,8 +2074,21 @@
 	   note in a row.  */
 	if (notice_source_line (insn))
 	  {
-	    (*debug_hooks->source_line) (last_linenum, last_filename);
+	    if (current_start_basic_block)
+	      {
+		current_start_basic_block = 0;
+		(*debug_hooks->source_line) (last_linenum, last_filename, LINE_FLAG_BASIC_BLOCK);
+	      }
+	    else 
+	      {
+		(*debug_hooks->source_line) (last_linenum, last_filename, 0);
+	      }
 	  }
+	else if (current_start_basic_block)
+	  {
+	    current_start_basic_block = 0;
+	    (*debug_hooks->source_line) (last_linenum, last_filename, LINE_FLAG_BASIC_BLOCK);
+	  }
 
 	if (GET_CODE (body) == ASM_INPUT)
 	  {
@@ -2498,6 +2514,7 @@
 	current_output_insn = debug_insn = 0;
       }
     }
+
   return NEXT_INSN (insn);
 }
 
Index: gcc/debug.c
===================================================================
--- gcc/debug.c	(revision 106485)
+++ gcc/debug.c	(working copy)
@@ -33,7 +33,7 @@
   debug_nothing_int_int,	         /* begin_block */
   debug_nothing_int_int,	         /* end_block */
   debug_true_tree,		         /* ignore_block */
-  debug_nothing_int_charstar,	         /* source_line */
+  debug_nothing_int_charstar_int,	 /* source_line */
   debug_nothing_int_charstar,	         /* begin_prologue */
   debug_nothing_int_charstar,	         /* end_prologue */
   debug_nothing_int_charstar,	         /* end_epilogue */
@@ -94,6 +94,13 @@
 }
 
 void
+debug_nothing_int_charstar_int (unsigned int line ATTRIBUTE_UNUSED,
+				const char *text ATTRIBUTE_UNUSED,
+				unsigned int flags ATTRIBUTE_UNUSED)
+{
+}
+
+void
 debug_nothing_int (unsigned int line ATTRIBUTE_UNUSED)
 {
 }
Index: gcc/debug.h
===================================================================
--- gcc/debug.h	(revision 106485)
+++ gcc/debug.h	(working copy)
@@ -59,7 +59,7 @@
   bool (* ignore_block) (tree);
 
   /* Record a source file location at (FILE, LINE).  */
-  void (* source_line) (unsigned int line, const char *file);
+  void (* source_line) (unsigned int line, const char *file, unsigned int flags);
 
   /* Called at start of prologue code.  LINE is the first line in the
      function.  This has been given the same prototype as source_line,
@@ -129,12 +129,16 @@
   int start_end_main_source_file;
 };
 
+
+#define LINE_FLAG_BASIC_BLOCK ((unsigned int)1)
+
 extern const struct gcc_debug_hooks *debug_hooks;
 
 /* The do-nothing hooks.  */
 extern void debug_nothing_void (void);
 extern void debug_nothing_charstar (const char *);
 extern void debug_nothing_int_charstar (unsigned int, const char *);
+extern void debug_nothing_int_charstar_int (unsigned int, const char *, unsigned int flags);
 extern void debug_nothing_int (unsigned int);
 extern void debug_nothing_int_int (unsigned int, unsigned int);
 extern void debug_nothing_tree (tree);
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 106485)
+++ gcc/dwarf2out.c	(working copy)
@@ -69,7 +69,7 @@
 #include "input.h"
 
 #ifdef DWARF2_DEBUGGING_INFO
-static void dwarf2out_source_line (unsigned int, const char *);
+static void dwarf2out_source_line (unsigned int, const char *, unsigned int flags);
 #endif
 
 /* DWARF2 Abbreviation Glossary:
@@ -2510,7 +2510,7 @@
      prologue case, not the eh frame case.  */
 #ifdef DWARF2_DEBUGGING_INFO
   if (file)
-    dwarf2out_source_line (line, file);
+    dwarf2out_source_line (line, file, 0);
 #endif
 }
 
@@ -13534,7 +13534,7 @@
    'line_info_table' for later output of the .debug_line section.  */
 
 static void
-dwarf2out_source_line (unsigned int line, const char *filename)
+dwarf2out_source_line (unsigned int line, const char *filename, unsigned int flags)
 {
   if (debug_info_level >= DINFO_LEVEL_NORMAL
       && line != 0)
@@ -13553,7 +13553,14 @@
 	  file_num = maybe_emit_file (file_num);
 
 	  /* Emit the .loc directive understood by GNU as.  */
-	  fprintf (asm_out_file, "\t.loc %d %d 0\n", file_num, line);
+	  if (flags & LINE_FLAG_BASIC_BLOCK) 
+	    {
+	      fprintf (asm_out_file, "\t.loc %d %d 0 basic_block\n", file_num, line);
+	    }
+	  else
+	    {
+	      fprintf (asm_out_file, "\t.loc %d %d 0 ;#test\n", file_num, line);
+	    }
 
 	  /* Indicate that line number info exists.  */
 	  line_info_table_in_use++;