Preserve programmer specified labels, and emit debug info for them even if

they are deleted.

From-SVN: r25883

gcc/ChangeLog

+Sun Mar 21 12:13:01 1999  Nick Clifton  <nickc@cygnus.com>
+
+	* flow.c (can_delete_label_p): Do not allow user specified
+	labels to be deleted.
+	* dwarf2out.c (gen_label_die): Generate addresses for deleted
+	(programmer specified) labels. 
+	* dwarfout.c (output_label_die): Generate addresses for deleted
+	(programmer specified) labels.
+
 1999-03-21  Manfred Hollstein  <manfred@s-direktnet.de>
 
 	* Makefile.in (xgcc$(exeext)): Add intl.o to list of files to be

gcc/dwarf2out.c

@@ -8583,7 +8583,13 @@ gen_label_die (decl, context_die)
   else
     {
       insn = DECL_RTL (decl);
-      if (GET_CODE (insn) == CODE_LABEL)
+
+      /* Deleted labels are programmer specified labels which have been
+	 eliminated because of various optimisations.  We still emit them
+	 here so that it is possible to put breakpoints on them.  */
+      if (GET_CODE (insn) == CODE_LABEL
+	  || ((GET_CODE (insn) == NOTE
+	       && NOTE_LINE_NUMBER (insn) == NOTE_INSN_DELETED_LABEL)))
 	{
 	  /* When optimization is enabled (via -O) some parts of the compiler 
 	     (e.g. jump.c and cse.c) may try to delete CODE_LABEL insns which 

gcc/dwarfout.c

@@ -3519,7 +3519,12 @@ output_label_die (arg)
     {
       register rtx insn = DECL_RTL (decl);
 
-      if (GET_CODE (insn) == CODE_LABEL)
+      /* Deleted labels are programmer specified labels which have been
+	 eliminated because of various optimisations.  We still emit them
+	 here so that it is possible to put breakpoints on them.  */
+      if (GET_CODE (insn) == CODE_LABEL
+	  || ((GET_CODE (insn) == NOTE
+	       && NOTE_LINE_NUMBER (insn) == NOTE_INSN_DELETED_LABEL)))
 	{
 	  char label[MAX_ARTIFICIAL_LABEL_BYTES];
 

gcc/flow.c

@@ -1649,6 +1649,7 @@ delete_block (b)
      notes.  */
 
   insn = b->head;
+  
   if (GET_CODE (insn) == CODE_LABEL)
     {
       rtx x, *prev = &exception_handler_labels;
@@ -1793,6 +1794,16 @@ can_delete_label_p (label)
     if (label == XEXP (x, 0))
       return 0;
 
+  /* User declared labels must be preserved, but we can
+     convert them into a NOTE instead. */
+  if (LABEL_NAME (label) != 0)
+    {
+      PUT_CODE (label, NOTE);
+      NOTE_LINE_NUMBER (label) = NOTE_INSN_DELETED_LABEL;
+      NOTE_SOURCE_FILE (label) = 0;
+      return 0;
+    }
+  
   return 1;
 }