alpha.c (alpha_start_function): Handle VMS_DEBUG_MAIN_POINTER

	* config/alpha/alpha.c (alpha_start_function):
	Handle VMS_DEBUG_MAIN_POINTER
	* config/alpha/vms.h (VMS_DEBUG_MAIN_POINTER): Define new macro.
	* doc/invoke.texi: Document -mdebug-main switch.

From-SVN: r150235

gcc/ChangeLog

+2009-07-29  Douglas B Rupp  <rupp@gnat.com>
+
+	* config/alpha/alpha.c (alpha_start_function):
+	Handle VMS_DEBUG_MAIN_POINTER
+	* config/alpha/vms.h (VMS_DEBUG_MAIN_POINTER): Define new macro.
+	* doc/invoke.texi: Document -mdebug-main switch.
+
 2009-07-29  Richard Henderson  <rth@redhat.com>
 
 	* cgraph.c (cgraph_set_call_stmt_including_clones): Tidy.

gcc/config/alpha/alpha.c

@@ -7837,6 +7837,17 @@ alpha_start_function (FILE *file, const char *fnname,
       TREE_ASM_WRITTEN (name_tree) = 1;
     }
 
+#if TARGET_ABI_OPEN_VMS
+  if (vms_debug_main
+      && strncmp (vms_debug_main, fnname, strlen (vms_debug_main)) == 0)
+    {
+      targetm.asm_out.globalize_label (asm_out_file, VMS_DEBUG_MAIN_POINTER);
+      ASM_OUTPUT_DEF (asm_out_file, VMS_DEBUG_MAIN_POINTER, fnname);
+      switch_to_section (text_section);
+      vms_debug_main = NULL;
+    }
+#endif
+
   alpha_fnname = fnname;
   sa_size = alpha_sa_size ();
 

gcc/config/alpha/vms.h

 /* Output variables, constants and external declarations, for GNU compiler.
-   Copyright (C) 1996, 1997, 1998, 2000, 2001, 2002, 2004, 2005, 2007, 2008
+   Copyright (C) 1996, 1997, 1998, 2000, 2001, 2002, 2004, 2005, 2007, 2008,
+   2009
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -50,6 +51,8 @@ along with GCC; see the file COPYING3.  If not see
 #undef TARGET_VERSION
 #define TARGET_VERSION fprintf (stderr, " (%s)", TARGET_NAME);           
 
+#define VMS_DEBUG_MAIN_POINTER "TRANSFER$BREAK$GO"
+
 #undef PCC_STATIC_STRUCT_RETURN
 
 /* "long" is 32 bits, but 64 bits for Ada.  */

gcc/doc/invoke.texi

@@ -534,7 +534,7 @@ Objective-C and Objective-C++ Dialects}.
 -mmemory-latency=@var{time}}
 
 @emph{DEC Alpha/VMS Options}
-@gccoptlist{-mvms-return-codes}
+@gccoptlist{-mvms-return-codes -mdebug-main=@var{prefix}}
 
 @emph{FR30 Options}
 @gccoptlist{-msmall-model -mno-lsim}
@@ -10582,8 +10582,13 @@ These @samp{-m} options are defined for the DEC Alpha/VMS implementations:
 @table @gcctabopt
 @item -mvms-return-codes
 @opindex mvms-return-codes
-Return VMS condition codes from main.  The default is to return POSIX
+Return VMS condition codes from main. The default is to return POSIX
 style condition (e.g.@: error) codes.
+
+@item -mdebug-main=@var{prefix}
+@opindex mdebug-main=@var{prefix}
+Flag the first routine whose name starts with @var{prefix} as the main
+routine for the debugger.
 @end table
 
 @node FR30 Options