Re: [RFA] Remove dependency on load address of environ

[Fred Fish <fnf@fred.ninemoons.com>]

> I proofread this patch and it looks correct to me, no problems found.
> I have not tested it though.

Peter Schauer found one problem with it, an sbrk not protected by HAVE_SBRK.
Here is a revised patch.

-Fred

Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.2546
diff -c -p -r1.2546 ChangeLog
*** ChangeLog	1 May 2002 03:14:05 -0000	1.2546
--- ChangeLog	1 May 2002 13:15:46 -0000
***************
*** 56,61 ****
--- 56,72 ----
  	(ppc_sysv_abi_push_arguments): Handle vector parameters.
  	* ppc-tdep.h (ppc_sysv_abi_broken_use_struct_convention): Export.
          
+ 2002-04-26  Fred Fish  <fnf@redhat.com>
+ 
+ 	* main.c (display_space_base): Add global variable.
+ 	(main): Initialize display_space_base by calling sbrk.
+ 
+ 	* main.c (captured_main): Add display_space_base decl, remove environ
+ 	decl and reference, remove lim variable, use display_space_base.
+ 	* top.c (command_loop): Ditto.
+ 	* event-top.c (command_handler): Ditto.
+ 	(command_line_handler_continuation): Ditto.
+ 
  2002-04-24  Pierre Muller  <ics.u-strasbg.fr>
  
  	* hpread.c (hpread_psymtab_to_symtab_1,
Index: top.c
===================================================================
RCS file: /cvs/src/src/gdb/top.c,v
retrieving revision 1.62
diff -c -p -r1.62 top.c
*** top.c	23 Apr 2002 03:00:57 -0000	1.62
--- top.c	1 May 2002 13:15:48 -0000
*************** command_loop (void)
*** 759,764 ****
--- 759,765 ----
  #endif
    extern int display_time;
    extern int display_space;
+   extern char *display_space_base;
  
    while (instream && !feof (instream))
      {
*************** command_loop (void)
*** 782,791 ****
        if (display_space)
  	{
  #ifdef HAVE_SBRK
! 	  extern char **environ;
! 	  char *lim = (char *) sbrk (0);
! 
! 	  space_at_cmd_start = (long) (lim - (char *) &environ);
  #endif
  	}
  
--- 783,789 ----
        if (display_space)
  	{
  #ifdef HAVE_SBRK
! 	  space_at_cmd_start = (char *) sbrk (0) - display_space_base;
  #endif
  	}
  
*************** command_loop (void)
*** 805,813 ****
        if (display_space)
  	{
  #ifdef HAVE_SBRK
! 	  extern char **environ;
! 	  char *lim = (char *) sbrk (0);
! 	  long space_now = lim - (char *) &environ;
  	  long space_diff = space_now - space_at_cmd_start;
  
  	  printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
--- 803,809 ----
        if (display_space)
  	{
  #ifdef HAVE_SBRK
! 	  long space_now = (char *) sbrk (0) - display_space_base;
  	  long space_diff = space_now - space_at_cmd_start;
  
  	  printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
Index: event-top.c
===================================================================
RCS file: /cvs/src/src/gdb/event-top.c,v
retrieving revision 1.20
diff -c -p -r1.20 event-top.c
*** event-top.c	27 Mar 2002 21:20:15 -0000	1.20
--- event-top.c	1 May 2002 13:15:51 -0000
*************** command_handler (char *command)
*** 475,480 ****
--- 475,481 ----
  #endif
    extern int display_time;
    extern int display_space;
+   extern char *display_space_base;
  
    quit_flag = 0;
    if (instream == stdin && stdin_is_tty)
*************** command_handler (char *command)
*** 494,503 ****
    if (display_space)
      {
  #ifdef HAVE_SBRK
!       extern char **environ;
!       char *lim = (char *) sbrk (0);
! 
!       space_at_cmd_start = (long) (lim - (char *) &environ);
  #endif
      }
  
--- 495,501 ----
    if (display_space)
      {
  #ifdef HAVE_SBRK
!       space_at_cmd_start = (char *) sbrk (0) - display_space_base;
  #endif
      }
  
*************** command_handler (char *command)
*** 538,546 ****
        if (display_space)
  	{
  #ifdef HAVE_SBRK
! 	  extern char **environ;
! 	  char *lim = (char *) sbrk (0);
! 	  long space_now = lim - (char *) &environ;
  	  long space_diff = space_now - space_at_cmd_start;
  
  	  printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
--- 536,542 ----
        if (display_space)
  	{
  #ifdef HAVE_SBRK
! 	  long space_now = (char *) sbrk (0) - display_space_base;
  	  long space_diff = space_now - space_at_cmd_start;
  
  	  printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
*************** command_line_handler_continuation (struc
*** 560,565 ****
--- 556,562 ----
  {
    extern int display_time;
    extern int display_space;
+   extern char *display_space_base;
  
    long time_at_cmd_start  = arg->data.longint;
    long space_at_cmd_start = arg->next->data.longint;
*************** command_line_handler_continuation (struc
*** 577,585 ****
    if (display_space)
      {
  #ifdef HAVE_SBRK
!       extern char **environ;
!       char *lim = (char *) sbrk (0);
!       long space_now = lim - (char *) &environ;
        long space_diff = space_now - space_at_cmd_start;
  
        printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
--- 574,580 ----
    if (display_space)
      {
  #ifdef HAVE_SBRK
!       long space_now = (char *) sbrk (0) - display_space_base;
        long space_diff = space_now - space_at_cmd_start;
  
        printf_unfiltered ("Space used: %ld (%c%ld for this command)\n",
Index: main.c
===================================================================
RCS file: /cvs/src/src/gdb/main.c,v
retrieving revision 1.16
diff -c -p -r1.16 main.c
*** main.c	17 Jan 2002 22:15:17 -0000	1.16
--- main.c	1 May 2002 13:15:52 -0000
*************** int display_time;
*** 45,50 ****
--- 45,54 ----
  
  int display_space;
  
+ /* Remember the lowest sbrk limit when display_space is nonzero. */
+ 
+ char *display_space_base;
+ 
  /* Whether this is the async version or not.  The async version is
     invoked on the command line with the -nw --async options.  In this
     version, the usual command_loop is substituted by and event loop which
*************** extern int gdbtk_test (char *);
*** 679,689 ****
    if (display_space)
      {
  #ifdef HAVE_SBRK
!       extern char **environ;
!       char *lim = (char *) sbrk (0);
! 
!       printf_unfiltered ("Startup size: data size %ld\n",
! 			 (long) (lim - (char *) &environ));
  #endif
      }
  
--- 683,690 ----
    if (display_space)
      {
  #ifdef HAVE_SBRK
!       long space_now = (char *) sbrk (0) - display_space_base;
!       printf_unfiltered ("Startup size: data size %ld\n", space_now);
  #endif
      }
  
*************** main (int argc, char **argv)
*** 731,736 ****
--- 732,740 ----
    struct captured_main_args args;
    args.argc = argc;
    args.argv = argv;
+ #ifdef HAVE_SBRK
+   display_space_base = sbrk (0);
+ #endif
    catch_errors (captured_main, &args, "", RETURN_MASK_ALL);
    return 0;
  }