Merge to Cygnus 961112 + add some support (not ready) for shared libs

1 files changed, 1499 insertions, 0 deletions

diff --git a/gnu/usr.bin/binutils/gdb/stack.c b/gnu/usr.bin/binutils/gdb/stack.c
new file mode 100644
index 00000000000..636903d25df
--- /dev/null
+++ b/gnu/usr.bin/binutils/gdb/stack.c
@@ -0,0 +1,1499 @@
+/* Print and select stack frames for GDB, the GNU debugger.
+   Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996
+   Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+
+#include "defs.h"
+#include "gdb_string.h"
+#include "value.h"
+#include "symtab.h"
+#include "gdbtypes.h"
+#include "expression.h"
+#include "language.h"
+#include "frame.h"
+#include "gdbcmd.h"
+#include "gdbcore.h"
+#include "target.h"
+#include "breakpoint.h"
+#include "demangle.h"
+#include "inferior.h"
+#include "annotate.h"
+#include "symfile.h"
+#include "objfiles.h"
+
+static void return_command PARAMS ((char *, int));
+
+static void down_command PARAMS ((char *, int));
+
+static void down_silently_command PARAMS ((char *, int));
+
+static void up_command PARAMS ((char *, int));
+
+static void up_silently_command PARAMS ((char *, int));
+
+static void frame_command PARAMS ((char *, int));
+
+static void select_frame_command PARAMS ((char *, int));
+
+static void args_info PARAMS ((char *, int));
+
+static void print_frame_arg_vars PARAMS ((struct frame_info *, GDB_FILE *));
+
+static void catch_info PARAMS ((char *, int));
+
+static void locals_info PARAMS ((char *, int));
+
+static void print_frame_label_vars PARAMS ((struct frame_info *, int,
+					    GDB_FILE *));
+
+static void print_frame_local_vars PARAMS ((struct frame_info *, GDB_FILE *));
+
+static int print_block_frame_labels PARAMS ((struct block *, int *,
+					     GDB_FILE *));
+
+static int print_block_frame_locals PARAMS ((struct block *,
+					     struct frame_info *,
+					     GDB_FILE *));
+
+static void backtrace_command PARAMS ((char *, int));
+
+static struct frame_info *parse_frame_specification PARAMS ((char *));
+
+static void frame_info PARAMS ((char *, int));
+
+extern int addressprint;	/* Print addresses, or stay symbolic only? */
+extern int info_verbose;	/* Verbosity of symbol reading msgs */
+extern int lines_to_list;	/* # of lines "list" command shows by default */
+
+/* The "selected" stack frame is used by default for local and arg access.
+   May be zero, for no selected frame.  */
+
+struct frame_info *selected_frame;
+
+/* Level of the selected frame:
+   0 for innermost, 1 for its caller, ...
+   or -1 for frame specified by address with no defined level.  */
+
+int selected_frame_level;
+
+/* Zero means do things normally; we are interacting directly with the
+   user.  One means print the full filename and linenumber when a
+   frame is printed, and do so in a format emacs18/emacs19.22 can
+   parse.  Two means print similar annotations, but in many more
+   cases and in a slightly different syntax.  */
+
+int annotation_level = 0;
+
+
+struct print_stack_frame_args {
+  struct frame_info *fi;
+  int level;
+  int source;
+  int args;
+};
+
+static int print_stack_frame_stub PARAMS ((char *));
+
+/* Pass the args the way catch_errors wants them.  */
+static int
+print_stack_frame_stub (args)
+     char *args;
+{
+  struct print_stack_frame_args *p = (struct print_stack_frame_args *)args;
+
+  print_frame_info (p->fi, p->level, p->source, p->args);
+  return 0;
+}
+
+/* Print a stack frame briefly.  FRAME_INFI should be the frame info
+   and LEVEL should be its level in the stack (or -1 for level not defined).
+   This prints the level, the function executing, the arguments,
+   and the file name and line number.
+   If the pc is not at the beginning of the source line,
+   the actual pc is printed at the beginning.
+
+   If SOURCE is 1, print the source line as well.
+   If SOURCE is -1, print ONLY the source line.  */
+
+void
+print_stack_frame (fi, level, source)
+     struct frame_info *fi;
+     int level;
+     int source;
+{
+  struct print_stack_frame_args args;
+
+  args.fi = fi;
+  args.level = level;
+  args.source = source;
+  args.args = 1;
+
+  catch_errors (print_stack_frame_stub, (char *)&args, "", RETURN_MASK_ALL);
+}
+
+struct print_args_args {
+  struct symbol *func;
+  struct frame_info *fi;
+};
+
+static int print_args_stub PARAMS ((char *));
+
+/* Pass the args the way catch_errors wants them.  */
+
+static int
+print_args_stub (args)
+     char *args;
+{
+  int numargs;
+  struct print_args_args *p = (struct print_args_args *)args;
+
+  FRAME_NUM_ARGS (numargs, (p->fi));
+  print_frame_args (p->func, p->fi, numargs, gdb_stdout);
+  return 0;
+}
+
+/* LEVEL is the level of the frame, or -1 if it is the innermost frame
+   but we don't want to print the level.  */
+
+void
+print_frame_info (fi, level, source, args)
+     struct frame_info *fi;
+     register int level;
+     int source;
+     int args;
+{
+  struct symtab_and_line sal;
+  struct symbol *func;
+  register char *funname = 0;
+  enum language funlang = language_unknown;
+
+#if 0
+  char buf[MAX_REGISTER_RAW_SIZE];
+  CORE_ADDR sp;
+
+  /* On the 68k, this spends too much time in m68k_find_saved_regs.  */
+
+  /* Get the value of SP_REGNUM relative to the frame.  */
+  get_saved_register (buf, (int *)NULL, (CORE_ADDR *)NULL,
+		      FRAME_INFO_ID (fi), SP_REGNUM, (enum lval_type *)NULL);
+  sp = extract_address (buf, REGISTER_RAW_SIZE (SP_REGNUM));
+
+  /* This is not a perfect test, because if a function alloca's some
+     memory, puts some code there, and then jumps into it, then the test
+     will succeed even though there is no call dummy.  Probably best is
+     to check for a bp_call_dummy breakpoint.  */
+  if (PC_IN_CALL_DUMMY (fi->pc, sp, fi->frame))
+#else
+  if (frame_in_dummy (fi))
+#endif
+    {
+      annotate_frame_begin (level == -1 ? 0 : level, fi->pc);
+
+      /* Do this regardless of SOURCE because we don't have any source
+	 to list for this frame.  */
+      if (level >= 0)
+	printf_filtered ("#%-2d ", level);
+      annotate_function_call ();
+      printf_filtered ("<function called from gdb>\n");
+      annotate_frame_end ();
+      return;
+    }
+  if (fi->signal_handler_caller)
+    {
+      annotate_frame_begin (level == -1 ? 0 : level, fi->pc);
+
+      /* Do this regardless of SOURCE because we don't have any source
+	 to list for this frame.  */
+      if (level >= 0)
+	printf_filtered ("#%-2d ", level);
+      annotate_signal_handler_caller ();
+      printf_filtered ("<signal handler called>\n");
+      annotate_frame_end ();
+      return;
+    }
+
+  /* If fi is not the innermost frame, that normally means that fi->pc
+     points to *after* the call instruction, and we want to get the line
+     containing the call, never the next line.  But if the next frame is
+     a signal_handler_caller or a dummy frame, then the next frame was
+     not entered as the result of a call, and we want to get the line
+     containing fi->pc.  */
+  sal =
+    find_pc_line (fi->pc,
+		  fi->next != NULL
+		  && !fi->next->signal_handler_caller
+		  && !frame_in_dummy (fi->next));
+
+  func = find_pc_function (fi->pc);
+  if (func)
+    {
+      /* In certain pathological cases, the symtabs give the wrong
+	 function (when we are in the first function in a file which
+	 is compiled without debugging symbols, the previous function
+	 is compiled with debugging symbols, and the "foo.o" symbol
+	 that is supposed to tell us where the file with debugging symbols
+	 ends has been truncated by ar because it is longer than 15
+	 characters).  This also occurs if the user uses asm() to create
+	 a function but not stabs for it (in a file compiled -g).
+
+	 So look in the minimal symbol tables as well, and if it comes
+	 up with a larger address for the function use that instead.
+	 I don't think this can ever cause any problems; there shouldn't
+	 be any minimal symbols in the middle of a function; if this is
+	 ever changed many parts of GDB will need to be changed (and we'll
+	 create a find_pc_minimal_function or some such).  */
+
+      struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (fi->pc);
+      if (msymbol != NULL
+	  && (SYMBOL_VALUE_ADDRESS (msymbol) 
+	      > BLOCK_START (SYMBOL_BLOCK_VALUE (func))))
+	{
+#if 0
+	  /* There is no particular reason to think the line number
+	     information is wrong.  Someone might have just put in
+	     a label with asm() but left the line numbers alone.  */
+	  /* In this case we have no way of knowing the source file
+	     and line number, so don't print them.  */
+	  sal.symtab = 0;
+#endif
+	  /* We also don't know anything about the function besides
+	     its address and name.  */
+	  func = 0;
+	  funname = SYMBOL_NAME (msymbol);
+	  funlang = SYMBOL_LANGUAGE (msymbol);
+	}
+      else
+	{
+	  funname = SYMBOL_NAME (func);
+	  funlang = SYMBOL_LANGUAGE (func);
+	}
+    }
+  else
+    {
+      struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (fi->pc);
+      if (msymbol != NULL)
+	{
+	  funname = SYMBOL_NAME (msymbol);
+	  funlang = SYMBOL_LANGUAGE (msymbol);
+	}
+    }
+
+  if (source >= 0 || !sal.symtab)
+    {
+      annotate_frame_begin (level == -1 ? 0 : level, fi->pc);
+
+      if (level >= 0)
+	printf_filtered ("#%-2d ", level);
+      if (addressprint)
+	if (fi->pc != sal.pc || !sal.symtab)
+	  {
+	    annotate_frame_address ();
+	    print_address_numeric (fi->pc, 1, gdb_stdout);
+	    annotate_frame_address_end ();
+	    printf_filtered (" in ");
+	  }
+      annotate_frame_function_name ();
+      fprintf_symbol_filtered (gdb_stdout, funname ? funname : "??", funlang,
+			       DMGL_ANSI);
+      wrap_here ("   ");
+      annotate_frame_args ();
+      fputs_filtered (" (", gdb_stdout);
+      if (args)
+	{
+	  struct print_args_args args;
+	  args.fi = fi;
+	  args.func = func;
+	  catch_errors (print_args_stub, (char *)&args, "", RETURN_MASK_ALL);
+	  QUIT;
+	}
+      printf_filtered (")");
+      if (sal.symtab && sal.symtab->filename)
+	{
+	  annotate_frame_source_begin ();
+          wrap_here ("   ");
+	  printf_filtered (" at ");
+	  annotate_frame_source_file ();
+	  printf_filtered ("%s", sal.symtab->filename);
+	  annotate_frame_source_file_end ();
+	  printf_filtered (":");
+	  annotate_frame_source_line ();
+	  printf_filtered ("%d", sal.line);
+	  annotate_frame_source_end ();
+	}
+
+#ifdef PC_LOAD_SEGMENT
+     /* If we couldn't print out function name but if can figure out what
+        load segment this pc value is from, at least print out some info
+	about its load segment. */
+      if (!funname)
+	{
+	  annotate_frame_where ();
+	  wrap_here ("  ");
+	  printf_filtered (" from %s", PC_LOAD_SEGMENT (fi->pc));
+	}
+#endif
+#ifdef PC_SOLIB
+      if (!funname)
+	{
+	  char *lib = PC_SOLIB (fi->pc);
+	  if (lib)
+	    {
+	      annotate_frame_where ();
+	      wrap_here ("  ");
+	      printf_filtered (" from %s", lib);
+	    }
+	}
+#endif
+      printf_filtered ("\n");
+    }
+
+  if ((source != 0) && sal.symtab)
+    {
+      int done = 0;
+      int mid_statement = source < 0 && fi->pc != sal.pc;
+      if (annotation_level)
+	done = identify_source_line (sal.symtab, sal.line, mid_statement,
+				     fi->pc);
+      if (!done)
+	{
+	  if (addressprint && mid_statement)
+	    {
+	      print_address_numeric (fi->pc, 1, gdb_stdout);
+	      printf_filtered ("\t");
+	    }
+	  if (print_frame_info_listing_hook)
+	    print_frame_info_listing_hook (sal.symtab, sal.line, sal.line + 1, 0);
+	  else
+	    print_source_lines (sal.symtab, sal.line, sal.line + 1, 0);
+	}
+      current_source_line = max (sal.line - lines_to_list/2, 1);
+    }
+  if (source != 0)
+    set_default_breakpoint (1, fi->pc, sal.symtab, sal.line);
+
+  annotate_frame_end ();
+
+  gdb_flush (gdb_stdout);
+}
+
+/* Read a frame specification in whatever the appropriate format is.
+   Call error() if the specification is in any way invalid (i.e.
+   this function never returns NULL).  */
+
+static struct frame_info *
+parse_frame_specification (frame_exp)
+     char *frame_exp;
+{
+  int numargs = 0;
+#define	MAXARGS	4
+  CORE_ADDR args[MAXARGS];
+  
+  if (frame_exp)
+    {
+      char *addr_string, *p;
+      struct cleanup *tmp_cleanup;
+
+      while (*frame_exp == ' ') frame_exp++;
+
+      while (*frame_exp)
+	{
+	  if (numargs > MAXARGS)
+	    error ("Too many args in frame specification");
+	  /* Parse an argument.  */
+          for (p = frame_exp; *p && *p != ' '; p++)
+	    ;
+	  addr_string = savestring(frame_exp, p - frame_exp);
+
+	  {
+	    tmp_cleanup = make_cleanup (free, addr_string);
+	    args[numargs++] = parse_and_eval_address (addr_string);
+	    do_cleanups (tmp_cleanup);
+	  }
+
+	  /* Skip spaces, move to possible next arg.  */
+	  while (*p == ' ') p++;
+	  frame_exp = p;
+	}
+    }
+
+  switch (numargs)
+    {
+    case 0:
+      if (selected_frame == NULL)
+	error ("No selected frame.");
+      return selected_frame;
+      /* NOTREACHED */
+    case 1:
+      {
+	int level = args[0];
+	struct frame_info *fid =
+	  find_relative_frame (get_current_frame (), &level);
+	struct frame_info *tfid;
+
+	if (level == 0)
+	  /* find_relative_frame was successful */
+	  return fid;
+
+	/* If SETUP_ARBITRARY_FRAME is defined, then frame specifications
+	   take at least 2 addresses.  It is important to detect this case
+	   here so that "frame 100" does not give a confusing error message
+	   like "frame specification requires two addresses".  This of course
+	   does not solve the "frame 100" problem for machines on which
+	   a frame specification can be made with one address.  To solve
+	   that, we need a new syntax for a specifying a frame by address.
+	   I think the cleanest syntax is $frame(0x45) ($frame(0x23,0x45) for
+	   two args, etc.), but people might think that is too much typing,
+	   so I guess *0x23,0x45 would be a possible alternative (commas
+	   really should be used instead of spaces to delimit; using spaces
+	   normally works in an expression).  */
+#ifdef SETUP_ARBITRARY_FRAME
+	error ("No frame %d", args[0]);
+#endif
+
+	/* If (s)he specifies the frame with an address, he deserves what
+	   (s)he gets.  Still, give the highest one that matches.  */
+
+	for (fid = get_current_frame ();
+	     fid && fid->frame != args[0];
+	     fid = get_prev_frame (fid))
+	  ;
+
+	if (fid)
+	  while ((tfid = get_prev_frame (fid)) &&
+		 (tfid->frame == args[0]))
+	    fid = tfid;
+	  
+	/* We couldn't identify the frame as an existing frame, but
+	   perhaps we can create one with a single argument.  */
+      }
+
+     default:
+#ifdef SETUP_ARBITRARY_FRAME
+      return SETUP_ARBITRARY_FRAME (numargs, args);
+#else
+      /* Usual case.  Do it here rather than have everyone supply
+	 a SETUP_ARBITRARY_FRAME that does this.  */
+      if (numargs == 1)
+	return create_new_frame (args[0], 0);
+      error ("Too many args in frame specification");
+#endif
+      /* NOTREACHED */
+    }
+  /* NOTREACHED */
+}
+
+/* FRAME_ARGS_ADDRESS_CORRECT is just like FRAME_ARGS_ADDRESS except
+   that if it is unsure about the answer, it returns 0
+   instead of guessing (this happens on the VAX and i960, for example).
+
+   On most machines, we never have to guess about the args address,
+   so FRAME_ARGS_ADDRESS{,_CORRECT} are the same.  */
+#if !defined (FRAME_ARGS_ADDRESS_CORRECT)
+#define FRAME_ARGS_ADDRESS_CORRECT FRAME_ARGS_ADDRESS
+#endif
+
+/* Print verbosely the selected frame or the frame at address ADDR.
+   This means absolutely all information in the frame is printed.  */
+
+static void
+frame_info (addr_exp, from_tty)
+     char *addr_exp;
+     int from_tty;
+{
+  struct frame_info *fi;
+  struct frame_saved_regs fsr;
+  struct symtab_and_line sal;
+  struct symbol *func;
+  struct symtab *s;
+  struct frame_info *calling_frame_info;
+  int i, count, numregs;
+  char *funname = 0;
+  enum language funlang = language_unknown;
+
+  if (!target_has_stack)
+    error ("No stack.");
+
+  fi = parse_frame_specification (addr_exp);
+  if (fi == NULL)
+    error ("Invalid frame specified.");
+
+  sal = find_pc_line (fi->pc,
+		      fi->next != NULL
+		      && !fi->next->signal_handler_caller
+		      && !frame_in_dummy (fi->next));
+  func = get_frame_function (fi);
+  s = find_pc_symtab(fi->pc);
+  if (func)
+    {
+      funname = SYMBOL_NAME (func);
+      funlang = SYMBOL_LANGUAGE (func);
+    }
+  else
+    {
+      register struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (fi->pc);
+      if (msymbol != NULL)
+	{
+	  funname = SYMBOL_NAME (msymbol);
+	  funlang = SYMBOL_LANGUAGE (msymbol);
+	}
+    }
+  calling_frame_info = get_prev_frame (fi);
+
+  if (!addr_exp && selected_frame_level >= 0)
+    {
+      printf_filtered ("Stack level %d, frame at ", selected_frame_level);
+      print_address_numeric (fi->frame, 1, gdb_stdout);
+      printf_filtered (":\n");
+    }
+  else
+    {
+      printf_filtered ("Stack frame at ");
+      print_address_numeric (fi->frame, 1, gdb_stdout);
+      printf_filtered (":\n");
+    }
+  printf_filtered (" %s = ", reg_names[PC_REGNUM]);
+  print_address_numeric (fi->pc, 1, gdb_stdout);
+
+  wrap_here ("   ");
+  if (funname)
+    {
+      printf_filtered (" in ");
+      fprintf_symbol_filtered (gdb_stdout, funname, funlang,
+			       DMGL_ANSI | DMGL_PARAMS);
+    }
+  wrap_here ("   ");
+  if (sal.symtab)
+    printf_filtered (" (%s:%d)", sal.symtab->filename, sal.line);
+  puts_filtered ("; ");
+  wrap_here ("    ");
+  printf_filtered ("saved %s ", reg_names[PC_REGNUM]);
+  print_address_numeric (FRAME_SAVED_PC (fi), 1, gdb_stdout);
+  printf_filtered ("\n");
+
+  {
+    int frameless = 0;
+#ifdef FRAMELESS_FUNCTION_INVOCATION
+    FRAMELESS_FUNCTION_INVOCATION (fi, frameless);
+#endif
+    if (frameless)
+      printf_filtered (" (FRAMELESS),");
+  }
+
+  if (calling_frame_info)
+    {
+      printf_filtered (" called by frame at ");
+      print_address_numeric (calling_frame_info->frame, 1, gdb_stdout);
+    }
+  if (fi->next && calling_frame_info)
+    puts_filtered (",");
+  wrap_here ("   ");
+  if (fi->next)
+    {
+      printf_filtered (" caller of frame at ");
+      print_address_numeric (fi->next->frame, 1, gdb_stdout);
+    }
+  if (fi->next || calling_frame_info)
+    puts_filtered ("\n");
+  if (s)
+    printf_filtered (" source language %s.\n", language_str (s->language));
+
+#ifdef PRINT_EXTRA_FRAME_INFO
+  PRINT_EXTRA_FRAME_INFO (fi);
+#endif
+
+  {
+    /* Address of the argument list for this frame, or 0.  */
+    CORE_ADDR arg_list = FRAME_ARGS_ADDRESS_CORRECT (fi);
+    /* Number of args for this frame, or -1 if unknown.  */
+    int numargs;
+
+    if (arg_list == 0)
+      printf_filtered (" Arglist at unknown address.\n");
+    else
+      {
+	printf_filtered (" Arglist at ");
+	print_address_numeric (arg_list, 1, gdb_stdout);
+	printf_filtered (",");
+
+	FRAME_NUM_ARGS (numargs, fi);
+	if (numargs < 0)
+	  puts_filtered (" args: ");
+	else if (numargs == 0)
+	  puts_filtered (" no args.");
+	else if (numargs == 1)
+	  puts_filtered (" 1 arg: ");
+	else
+	  printf_filtered (" %d args: ", numargs);
+	print_frame_args (func, fi, numargs, gdb_stdout);
+	puts_filtered ("\n");
+      }
+  }
+  {
+    /* Address of the local variables for this frame, or 0.  */
+    CORE_ADDR arg_list = FRAME_LOCALS_ADDRESS (fi);
+
+    if (arg_list == 0)
+      printf_filtered (" Locals at unknown address,");
+    else
+      {
+	printf_filtered (" Locals at ");
+	print_address_numeric (arg_list, 1, gdb_stdout);
+	printf_filtered (",");
+      }
+  }
+
+#if defined (FRAME_FIND_SAVED_REGS)  
+  get_frame_saved_regs (fi, &fsr);
+  /* The sp is special; what's returned isn't the save address, but
+     actually the value of the previous frame's sp.  */
+  printf_filtered (" Previous frame's sp is ");
+  print_address_numeric (fsr.regs[SP_REGNUM], 1, gdb_stdout);
+  printf_filtered ("\n");
+  count = 0;
+  numregs = ARCH_NUM_REGS;
+  for (i = 0; i < numregs; i++)
+    if (fsr.regs[i] && i != SP_REGNUM)
+      {
+	if (count == 0)
+	  puts_filtered (" Saved registers:\n ");
+	else
+	  puts_filtered (",");
+	wrap_here (" ");
+	printf_filtered (" %s at ", reg_names[i]);
+	print_address_numeric (fsr.regs[i], 1, gdb_stdout);
+	count++;
+      }
+  if (count)
+    puts_filtered ("\n");
+#else  /* Have FRAME_FIND_SAVED_REGS.  */
+  /* We could get some information about saved registers by calling
+     get_saved_register on each register.  Which info goes with which frame
+     is necessarily lost, however, and I suspect that the users don't care
+     whether they get the info.  */
+  puts_filtered ("\n");
+#endif /* Have FRAME_FIND_SAVED_REGS.  */
+}
+
+#if 0
+/* Set a limit on the number of frames printed by default in a
+   backtrace.  */
+
+static int backtrace_limit;
+
+static void
+set_backtrace_limit_command (count_exp, from_tty)
+     char *count_exp;
+     int from_tty;
+{
+  int count = parse_and_eval_address (count_exp);
+
+  if (count < 0)
+    error ("Negative argument not meaningful as backtrace limit.");
+
+  backtrace_limit = count;
+}
+
+static void
+backtrace_limit_info (arg, from_tty)
+     char *arg;
+     int from_tty;
+{
+  if (arg)
+    error ("\"Info backtrace-limit\" takes no arguments.");
+
+  printf_unfiltered ("Backtrace limit: %d.\n", backtrace_limit);
+}
+#endif
+
+/* Print briefly all stack frames or just the innermost COUNT frames.  */
+
+static void
+backtrace_command (count_exp, from_tty)
+     char *count_exp;
+     int from_tty;
+{
+  struct frame_info *fi;
+  register int count;
+  register int i;
+  register struct frame_info *trailing;
+  register int trailing_level;
+
+  if (!target_has_stack)
+    error ("No stack.");
+
+  /* The following code must do two things.  First, it must
+     set the variable TRAILING to the frame from which we should start
+     printing.  Second, it must set the variable count to the number
+     of frames which we should print, or -1 if all of them.  */
+  trailing = get_current_frame ();
+  trailing_level = 0;
+  if (count_exp)
+    {
+      count = parse_and_eval_address (count_exp);
+      if (count < 0)
+	{
+	  struct frame_info *current;
+
+	  count = -count;
+
+	  current = trailing;
+	  while (current && count--)
+	    {
+	      QUIT;
+	      current = get_prev_frame (current);
+	    }
+	  
+	  /* Will stop when CURRENT reaches the top of the stack.  TRAILING
+	     will be COUNT below it.  */
+	  while (current)
+	    {
+	      QUIT;
+	      trailing = get_prev_frame (trailing);
+	      current = get_prev_frame (current);
+	      trailing_level++;
+	    }
+	  
+	  count = -1;
+	}
+    }
+  else
+    count = -1;
+
+  if (info_verbose)
+    {
+      struct partial_symtab *ps;
+      
+      /* Read in symbols for all of the frames.  Need to do this in
+	 a separate pass so that "Reading in symbols for xxx" messages
+	 don't screw up the appearance of the backtrace.  Also
+	 if people have strong opinions against reading symbols for
+	 backtrace this may have to be an option.  */
+      i = count;
+      for (fi = trailing;
+	   fi != NULL && i--;
+	   fi = get_prev_frame (fi))
+	{
+	  QUIT;
+	  ps = find_pc_psymtab (fi->pc);
+	  if (ps)
+	    PSYMTAB_TO_SYMTAB (ps);	/* Force syms to come in */
+	}
+    }
+
+  for (i = 0, fi = trailing;
+       fi && count--;
+       i++, fi = get_prev_frame (fi))
+    {
+      QUIT;
+
+      /* Don't use print_stack_frame; if an error() occurs it probably
+	 means further attempts to backtrace would fail (on the other
+	 hand, perhaps the code does or could be fixed to make sure
+	 the frame->prev field gets set to NULL in that case).  */
+      print_frame_info (fi, trailing_level + i, 0, 1);
+    }
+
+  /* If we've stopped before the end, mention that.  */
+  if (fi && from_tty)
+    printf_filtered ("(More stack frames follow...)\n");
+}
+
+/* Print the local variables of a block B active in FRAME.
+   Return 1 if any variables were printed; 0 otherwise.  */
+
+static int
+print_block_frame_locals (b, fi, stream)
+     struct block *b;
+     register struct frame_info *fi;
+     register GDB_FILE *stream;
+{
+  int nsyms;
+  register int i;
+  register struct symbol *sym;
+  register int values_printed = 0;
+
+  nsyms = BLOCK_NSYMS (b);
+
+  for (i = 0; i < nsyms; i++)
+    {
+      sym = BLOCK_SYM (b, i);
+      switch (SYMBOL_CLASS (sym))
+	{
+	case LOC_LOCAL:
+	case LOC_REGISTER:
+	case LOC_STATIC:
+	case LOC_BASEREG:
+	  values_printed = 1;
+	  fputs_filtered (SYMBOL_SOURCE_NAME (sym), stream);
+	  fputs_filtered (" = ", stream);
+	  print_variable_value (sym, fi, stream);
+	  fprintf_filtered (stream, "\n");
+	  break;
+
+	default:
+	  /* Ignore symbols which are not locals.  */
+	  break;
+	}
+    }
+  return values_printed;
+}
+
+/* Same, but print labels.  */
+
+static int
+print_block_frame_labels (b, have_default, stream)
+     struct block *b;
+     int *have_default;
+     register GDB_FILE *stream;
+{
+  int nsyms;
+  register int i;
+  register struct symbol *sym;
+  register int values_printed = 0;
+
+  nsyms = BLOCK_NSYMS (b);
+
+  for (i = 0; i < nsyms; i++)
+    {
+      sym = BLOCK_SYM (b, i);
+      if (STREQ (SYMBOL_NAME (sym), "default"))
+	{
+	  if (*have_default)
+	    continue;
+	  *have_default = 1;
+	}
+      if (SYMBOL_CLASS (sym) == LOC_LABEL)
+	{
+	  struct symtab_and_line sal;
+	  sal = find_pc_line (SYMBOL_VALUE_ADDRESS (sym), 0);
+	  values_printed = 1;
+	  fputs_filtered (SYMBOL_SOURCE_NAME (sym), stream);
+	  if (addressprint)
+	    {
+	      fprintf_filtered (stream, " ");
+	      print_address_numeric (SYMBOL_VALUE_ADDRESS (sym), 1, stream);
+	    }
+	  fprintf_filtered (stream, " in file %s, line %d\n",
+			    sal.symtab->filename, sal.line);
+	}
+    }
+  return values_printed;
+}
+
+/* Print on STREAM all the local variables in frame FRAME,
+   including all the blocks active in that frame
+   at its current pc.
+
+   Returns 1 if the job was done,
+   or 0 if nothing was printed because we have no info
+   on the function running in FRAME.  */
+
+static void
+print_frame_local_vars (fi, stream)
+     register struct frame_info *fi;
+     register GDB_FILE *stream;
+{
+  register struct block *block = get_frame_block (fi);
+  register int values_printed = 0;
+
+  if (block == 0)
+    {
+      fprintf_filtered (stream, "No symbol table info available.\n");
+      return;
+    }
+  
+  while (block != 0)
+    {
+      if (print_block_frame_locals (block, fi, stream))
+	values_printed = 1;
+      /* After handling the function's top-level block, stop.
+	 Don't continue to its superblock, the block of
+	 per-file symbols.  */
+      if (BLOCK_FUNCTION (block))
+	break;
+      block = BLOCK_SUPERBLOCK (block);
+    }
+
+  if (!values_printed)
+    {
+      fprintf_filtered (stream, "No locals.\n");
+    }
+}
+
+/* Same, but print labels.  */
+
+static void
+print_frame_label_vars (fi, this_level_only, stream)
+     register struct frame_info *fi;
+     int this_level_only;
+     register GDB_FILE *stream;
+{
+  register struct blockvector *bl;
+  register struct block *block = get_frame_block (fi);
+  register int values_printed = 0;
+  int index, have_default = 0;
+  char *blocks_printed;
+  CORE_ADDR pc = fi->pc;
+
+  if (block == 0)
+    {
+      fprintf_filtered (stream, "No symbol table info available.\n");
+      return;
+    }
+
+  bl = blockvector_for_pc (BLOCK_END (block) - 4, &index);
+  blocks_printed = (char *) alloca (BLOCKVECTOR_NBLOCKS (bl) * sizeof (char));
+  memset (blocks_printed, 0, BLOCKVECTOR_NBLOCKS (bl) * sizeof (char));
+
+  while (block != 0)
+    {
+      CORE_ADDR end = BLOCK_END (block) - 4;
+      int last_index;
+
+      if (bl != blockvector_for_pc (end, &index))
+	error ("blockvector blotch");
+      if (BLOCKVECTOR_BLOCK (bl, index) != block)
+	error ("blockvector botch");
+      last_index = BLOCKVECTOR_NBLOCKS (bl);
+      index += 1;
+
+      /* Don't print out blocks that have gone by.  */
+      while (index < last_index
+	     && BLOCK_END (BLOCKVECTOR_BLOCK (bl, index)) < pc)
+	index++;
+
+      while (index < last_index
+	     && BLOCK_END (BLOCKVECTOR_BLOCK (bl, index)) < end)
+	{
+	  if (blocks_printed[index] == 0)
+	    {
+	      if (print_block_frame_labels (BLOCKVECTOR_BLOCK (bl, index), &have_default, stream))
+		values_printed = 1;
+	      blocks_printed[index] = 1;
+	    }
+	  index++;
+	}
+      if (have_default)
+	return;
+      if (values_printed && this_level_only)
+	return;
+
+      /* After handling the function's top-level block, stop.
+	 Don't continue to its superblock, the block of
+	 per-file symbols.  */
+      if (BLOCK_FUNCTION (block))
+	break;
+      block = BLOCK_SUPERBLOCK (block);
+    }
+
+  if (!values_printed && !this_level_only)
+    {
+      fprintf_filtered (stream, "No catches.\n");
+    }
+}
+
+/* ARGSUSED */
+static void
+locals_info (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  if (!selected_frame)
+    error ("No frame selected.");
+  print_frame_local_vars (selected_frame, gdb_stdout);
+}
+
+static void
+catch_info (ignore, from_tty)
+     char *ignore;
+     int from_tty;
+{
+  if (!selected_frame)
+    error ("No frame selected.");
+  print_frame_label_vars (selected_frame, 0, gdb_stdout);
+}
+
+static void
+print_frame_arg_vars (fi, stream)
+     register struct frame_info *fi;
+     register GDB_FILE *stream;
+{
+  struct symbol *func = get_frame_function (fi);
+  register struct block *b;
+  int nsyms;
+  register int i;
+  register struct symbol *sym, *sym2;
+  register int values_printed = 0;
+
+  if (func == 0)
+    {
+      fprintf_filtered (stream, "No symbol table info available.\n");
+      return;
+    }
+
+  b = SYMBOL_BLOCK_VALUE (func);
+  nsyms = BLOCK_NSYMS (b);
+
+  for (i = 0; i < nsyms; i++)
+    {
+      sym = BLOCK_SYM (b, i);
+      switch (SYMBOL_CLASS (sym))
+	{
+	case LOC_ARG:
+	case LOC_LOCAL_ARG:
+	case LOC_REF_ARG:
+	case LOC_REGPARM:
+	case LOC_REGPARM_ADDR:
+	case LOC_BASEREG_ARG:
+	  values_printed = 1;
+	  fputs_filtered (SYMBOL_SOURCE_NAME (sym), stream);
+	  fputs_filtered (" = ", stream);
+
+	  /* We have to look up the symbol because arguments can have
+	     two entries (one a parameter, one a local) and the one we
+	     want is the local, which lookup_symbol will find for us.
+	     This includes gcc1 (not gcc2) on the sparc when passing a
+	     small structure and gcc2 when the argument type is float
+	     and it is passed as a double and converted to float by
+	     the prologue (in the latter case the type of the LOC_ARG
+	     symbol is double and the type of the LOC_LOCAL symbol is
+	     float).  There are also LOC_ARG/LOC_REGISTER pairs which
+	     are not combined in symbol-reading.  */
+
+	  sym2 = lookup_symbol (SYMBOL_NAME (sym),
+			b, VAR_NAMESPACE, (int *)NULL, (struct symtab **)NULL);
+	  print_variable_value (sym2, fi, stream);
+	  fprintf_filtered (stream, "\n");
+	  break;
+
+	default:
+	  /* Don't worry about things which aren't arguments.  */
+	  break;
+	}
+    }
+
+  if (!values_printed)
+    {
+      fprintf_filtered (stream, "No arguments.\n");
+    }
+}
+
+static void
+args_info (ignore, from_tty)
+     char *ignore;
+     int from_tty;
+{
+  if (!selected_frame)
+    error ("No frame selected.");
+  print_frame_arg_vars (selected_frame, gdb_stdout);
+}
+
+/* Select frame FI, and note that its stack level is LEVEL.
+   LEVEL may be -1 if an actual level number is not known.  */
+
+void
+select_frame (fi, level)
+     struct frame_info *fi;
+     int level;
+{
+  register struct symtab *s;
+
+  selected_frame = fi;
+  selected_frame_level = level;
+
+  /* Ensure that symbols for this frame are read in.  Also, determine the
+     source language of this frame, and switch to it if desired.  */
+  if (fi)
+  {
+    s = find_pc_symtab (fi->pc);
+    if (s 
+	&& s->language != current_language->la_language
+	&& s->language != language_unknown
+	&& language_mode == language_mode_auto) {
+      set_language(s->language);
+    }
+  }
+}
+
+/* Store the selected frame and its level into *FRAMEP and *LEVELP.
+   If there is no selected frame, *FRAMEP is set to NULL.  */
+
+void
+record_selected_frame (frameaddrp, levelp)
+     CORE_ADDR *frameaddrp;
+     int *levelp;
+{
+  *frameaddrp = selected_frame ? selected_frame->frame : 0;
+  *levelp = selected_frame_level;
+}
+
+/* Return the symbol-block in which the selected frame is executing.
+   Can return zero under various legitimate circumstances.  */
+
+struct block *
+get_selected_block ()
+{
+  if (!target_has_stack)
+    return 0;
+
+  if (!selected_frame)
+    return get_current_block ();
+  return get_frame_block (selected_frame);
+}
+
+/* Find a frame a certain number of levels away from FRAME.
+   LEVEL_OFFSET_PTR points to an int containing the number of levels.
+   Positive means go to earlier frames (up); negative, the reverse.
+   The int that contains the number of levels is counted toward
+   zero as the frames for those levels are found.
+   If the top or bottom frame is reached, that frame is returned,
+   but the final value of *LEVEL_OFFSET_PTR is nonzero and indicates
+   how much farther the original request asked to go.  */
+
+struct frame_info *
+find_relative_frame (frame, level_offset_ptr)
+     register struct frame_info *frame;
+     register int *level_offset_ptr;
+{
+  register struct frame_info *prev;
+  register struct frame_info *frame1;
+
+  /* Going up is simple: just do get_prev_frame enough times
+     or until initial frame is reached.  */
+  while (*level_offset_ptr > 0)
+    {
+      prev = get_prev_frame (frame);
+      if (prev == 0)
+	break;
+      (*level_offset_ptr)--;
+      frame = prev;
+    }
+  /* Going down is just as simple.  */
+  if (*level_offset_ptr < 0)
+    {
+      while (*level_offset_ptr < 0) {
+	frame1 = get_next_frame (frame);
+	if (!frame1)
+	  break;
+	frame = frame1;
+	(*level_offset_ptr)++;
+      }
+    }
+  return frame;
+}
+
+/* The "select_frame" command.  With no arg, NOP.
+   With arg LEVEL_EXP, select the frame at level LEVEL if it is a
+   valid level.  Otherwise, treat level_exp as an address expression
+   and select it.  See parse_frame_specification for more info on proper
+   frame expressions. */
+
+/* ARGSUSED */
+static void
+select_frame_command (level_exp, from_tty)
+     char *level_exp;
+     int from_tty;
+{
+  register struct frame_info *frame, *frame1;
+  unsigned int level = 0;
+
+  if (!target_has_stack)
+    error ("No stack.");
+
+  frame = parse_frame_specification (level_exp);
+
+  /* Try to figure out what level this frame is.  But if there is
+     no current stack, don't error out -- let the user set one.  */
+  frame1 = 0;
+  if (get_current_frame()) {
+    for (frame1 = get_prev_frame (0);
+	 frame1 && frame1 != frame;
+	 frame1 = get_prev_frame (frame1))
+      level++;
+  }
+
+  if (!frame1)
+    level = 0;
+
+  select_frame (frame, level);
+}
+
+/* The "frame" command.  With no arg, print selected frame briefly.
+   With arg, behaves like select_frame and then prints the selected
+   frame.  */
+
+static void
+frame_command (level_exp, from_tty)
+     char *level_exp;
+     int from_tty;
+{
+  select_frame_command (level_exp, from_tty);
+  print_stack_frame (selected_frame, selected_frame_level, 1);
+}
+
+/* Select the frame up one or COUNT stack levels
+   from the previously selected frame, and print it briefly.  */
+
+/* ARGSUSED */
+static void
+up_silently_command (count_exp, from_tty)
+     char *count_exp;
+     int from_tty;
+{
+  register struct frame_info *fi;
+  int count = 1, count1;
+  if (count_exp)
+    count = parse_and_eval_address (count_exp);
+  count1 = count;
+  
+  if (target_has_stack == 0 || selected_frame == 0)
+    error ("No stack.");
+
+  fi = find_relative_frame (selected_frame, &count1);
+  if (count1 != 0 && count_exp == 0)
+    error ("Initial frame selected; you cannot go up.");
+  select_frame (fi, selected_frame_level + count - count1);
+}
+
+static void
+up_command (count_exp, from_tty)
+     char *count_exp;
+     int from_tty;
+{
+  up_silently_command (count_exp, from_tty);
+  print_stack_frame (selected_frame, selected_frame_level, 1);
+}
+
+/* Select the frame down one or COUNT stack levels
+   from the previously selected frame, and print it briefly.  */
+
+/* ARGSUSED */
+static void
+down_silently_command (count_exp, from_tty)
+     char *count_exp;
+     int from_tty;
+{
+  register struct frame_info *frame;
+  int count = -1, count1;
+  if (count_exp)
+    count = - parse_and_eval_address (count_exp);
+  count1 = count;
+  
+  if (target_has_stack == 0 || selected_frame == 0)
+    error ("No stack.");
+
+  frame = find_relative_frame (selected_frame, &count1);
+  if (count1 != 0 && count_exp == 0)
+    {
+
+      /* We only do this if count_exp is not specified.  That way "down"
+	 means to really go down (and let me know if that is
+	 impossible), but "down 9999" can be used to mean go all the way
+	 down without getting an error.  */
+
+      error ("Bottom (i.e., innermost) frame selected; you cannot go down.");
+    }
+
+  select_frame (frame, selected_frame_level + count - count1);
+}
+
+
+static void
+down_command (count_exp, from_tty)
+     char *count_exp;
+     int from_tty;
+{
+  down_silently_command (count_exp, from_tty);
+  print_stack_frame (selected_frame, selected_frame_level, 1);
+}
+
+static void
+return_command (retval_exp, from_tty)
+     char *retval_exp;
+     int from_tty;
+{
+  struct symbol *thisfun;
+  CORE_ADDR selected_frame_addr;
+  CORE_ADDR selected_frame_pc;
+  struct frame_info *frame;
+  value_ptr return_value = NULL;
+
+  if (selected_frame == NULL)
+    error ("No selected frame.");
+  thisfun = get_frame_function (selected_frame);
+  selected_frame_addr = FRAME_FP (selected_frame);
+  selected_frame_pc = selected_frame->pc;
+
+  /* Compute the return value (if any -- possibly getting errors here).  */
+
+  if (retval_exp)
+    {
+      struct type *return_type = NULL;
+
+      return_value = parse_and_eval (retval_exp);
+
+      /* Cast return value to the return type of the function.  */
+      if (thisfun != NULL)
+	return_type = TYPE_TARGET_TYPE (SYMBOL_TYPE (thisfun));
+      if (return_type == NULL)
+	return_type = builtin_type_int;
+      return_value = value_cast (return_type, return_value);
+
+      /* Make sure we have fully evaluated it, since
+	 it might live in the stack frame we're about to pop.  */
+      if (VALUE_LAZY (return_value))
+	value_fetch_lazy (return_value);
+    }
+
+  /* If interactive, require confirmation.  */
+
+  if (from_tty)
+    {
+      if (thisfun != 0)
+	{
+	  if (!query ("Make %s return now? ", SYMBOL_SOURCE_NAME (thisfun)))
+	    {
+	      error ("Not confirmed.");
+	      /* NOTREACHED */
+	    }
+	}
+      else
+	if (!query ("Make selected stack frame return now? "))
+	  error ("Not confirmed.");
+    }
+
+  /* Do the real work.  Pop until the specified frame is current.  We
+     use this method because the selected_frame is not valid after
+     a POP_FRAME.  The pc comparison makes this work even if the
+     selected frame shares its fp with another frame.  */
+
+  while (selected_frame_addr != (frame = get_current_frame())->frame
+	 || selected_frame_pc != frame->pc)
+    POP_FRAME;
+
+  /* Then pop that frame.  */
+
+  POP_FRAME;
+
+  /* Compute the return value (if any) and store in the place
+     for return values.  */
+
+  if (retval_exp)
+    set_return_value (return_value);
+
+  /* If interactive, print the frame that is now current.  */
+
+  if (from_tty)
+    frame_command ("0", 1);
+  else
+    select_frame_command ("0", 0);
+}
+
+/* Gets the language of the current frame.  */
+
+enum language
+get_frame_language()
+{
+  register struct symtab *s;
+  enum language flang;		/* The language of the current frame */
+   
+  if (selected_frame)
+    {
+      s = find_pc_symtab(selected_frame->pc);
+      if (s)
+	flang = s->language;
+      else
+	flang = language_unknown;
+    }
+  else
+    flang = language_unknown;
+
+  return flang;
+}
+
+void
+_initialize_stack ()
+{
+#if 0  
+  backtrace_limit = 30;
+#endif
+
+  add_com ("return", class_stack, return_command,
+	   "Make selected stack frame return to its caller.\n\
+Control remains in the debugger, but when you continue\n\
+execution will resume in the frame above the one now selected.\n\
+If an argument is given, it is an expression for the value to return.");
+
+  add_com ("up", class_stack, up_command,
+	   "Select and print stack frame that called this one.\n\
+An argument says how many frames up to go.");
+  add_com ("up-silently", class_support, up_silently_command,
+	   "Same as the `up' command, but does not print anything.\n\
+This is useful in command scripts.");
+
+  add_com ("down", class_stack, down_command,
+	   "Select and print stack frame called by this one.\n\
+An argument says how many frames down to go.");
+  add_com_alias ("do", "down", class_stack, 1);
+  add_com_alias ("dow", "down", class_stack, 1);
+  add_com ("down-silently", class_support, down_silently_command,
+	   "Same as the `down' command, but does not print anything.\n\
+This is useful in command scripts.");
+
+  add_com ("frame", class_stack, frame_command,
+	   "Select and print a stack frame.\n\
+With no argument, print the selected stack frame.  (See also \"info frame\").\n\
+An argument specifies the frame to select.\n\
+It can be a stack frame number or the address of the frame.\n\
+With argument, nothing is printed if input is coming from\n\
+a command file or a user-defined command.");
+
+  add_com_alias ("f", "frame", class_stack, 1);
+
+  add_com ("select-frame", class_stack, select_frame_command,
+	   "Select a stack frame without printing anything.\n\
+An argument specifies the frame to select.\n\
+It can be a stack frame number or the address of the frame.\n");
+
+  add_com ("backtrace", class_stack, backtrace_command,
+	   "Print backtrace of all stack frames, or innermost COUNT frames.\n\
+With a negative argument, print outermost -COUNT frames.");
+  add_com_alias ("bt", "backtrace", class_stack, 0);
+  add_com_alias ("where", "backtrace", class_alias, 0);
+  add_info ("stack", backtrace_command,
+	    "Backtrace of the stack, or innermost COUNT frames.");
+  add_info_alias ("s", "stack", 1);
+  add_info ("frame", frame_info,
+	    "All about selected stack frame, or frame at ADDR.");
+  add_info_alias ("f", "frame", 1);
+  add_info ("locals", locals_info,
+	    "Local variables of current stack frame.");
+  add_info ("args", args_info,
+	    "Argument variables of current stack frame.");
+  add_info ("catch", catch_info,
+	    "Exceptions that can be caught in the current stack frame.");
+
+#if 0
+  add_cmd ("backtrace-limit", class_stack, set_backtrace_limit_command, 
+	   "Specify maximum number of frames for \"backtrace\" to print by default.",
+	   &setlist);
+  add_info ("backtrace-limit", backtrace_limit_info,
+	    "The maximum number of frames for \"backtrace\" to print by default.");
+#endif
+}