source.c

早期freebsd实现

	setfile_command(arg, from_tty);

	/* if we got back, command was successful */
	i = push_stack_ptr;
	push_stack[i].symtab = cursym;
	push_stack[i].line = curline;
	push_stack_ptr = (i + 1) & (PUSH_STACK_SIZE - 1);
}

static void
pop_file_command (arg, from_tty)
	char *arg;
	int from_tty;
{
	register unsigned int i = push_stack_ptr;

	/* if there's something on the stack, pop it & clear the slot. */
	i = (i + (PUSH_STACK_SIZE - 1)) & (PUSH_STACK_SIZE - 1);
	if (push_stack[i].symtab) {
		current_source_symtab = push_stack[i].symtab;
		first_line_listed = current_source_line = push_stack[i].line;
		push_stack[i].symtab = NULL;
		push_stack_ptr = i;
	}
}

static void
list_command (arg, from_tty)
     char *arg;
     int from_tty;
{
  struct symtabs_and_lines sals, sals_end;
  struct symtab_and_line sal, sal_end;
  struct symbol *sym;
  char *arg1;
  int no_end = 1;
  int dummy_end = 0;
  int dummy_beg = 0;
  int linenum_beg = 0;
  char *p;

  if (!have_full_symbols () && !have_partial_symbols())
    error ("No symbol table is loaded.  Use the \"file\" command.");

  /* Pull in a current source symtab if necessary */
  if (current_source_symtab == 0 &&
      (arg == 0 || arg[0] == '+' || arg[0] == '-'))
    select_source_symtab (0);

  /* "l" or "l +" lists next ten lines.  */

  if (arg == 0 || !strcmp (arg, "+"))
    {
      if (current_source_symtab == 0)
	error ("No default source file yet.  Do \"help list\".");
      print_source_lines (current_source_symtab, current_source_line,
			  current_source_line + lines_to_list, 0);
      return;
    }

  /* "l -" lists previous ten lines, the ones before the ten just listed.  */
  if (!strcmp (arg, "-"))
    {
      if (current_source_symtab == 0)
	error ("No default source file yet.  Do \"help list\".");
      print_source_lines (current_source_symtab,
			  max (first_line_listed - lines_to_list, 1),
			  first_line_listed, 0);
      return;
    }

  /* Now if there is only one argument, decode it in SAL
     and set NO_END.
     If there are two arguments, decode them in SAL and SAL_END
     and clear NO_END; however, if one of the arguments is blank,
     set DUMMY_BEG or DUMMY_END to record that fact.  */

  arg1 = arg;
  if (*arg1 == ',')
    dummy_beg = 1;
  else
    {
      sals = decode_line_1 (&arg1, 0, 0, 0);

      if (! sals.nelts) return;  /*  C++  */
      if (sals.nelts > 1)
	{
	  ambiguous_line_spec (&sals);
	  free (sals.sals);
	  return;
	}

      sal = sals.sals[0];
      free (sals.sals);
    }

  /* Record whether the BEG arg is all digits.  */

  for (p = arg; p != arg1 && *p >= '0' && *p <= '9'; p++);
  linenum_beg = (p == arg1);

  while (*arg1 == ' ' || *arg1 == '\t')
    arg1++;
  if (*arg1 == ',')
    {
      no_end = 0;
      arg1++;
      while (*arg1 == ' ' || *arg1 == '\t')
	arg1++;
      if (*arg1 == 0)
	dummy_end = 1;
      else
	{
	  if (dummy_beg)
	    sals_end = decode_line_1 (&arg1, 0, 0, 0);
	  else
	    sals_end = decode_line_1 (&arg1, 0, sal.symtab, sal.line);
	  if (sals_end.nelts == 0) 
	    return;
	  if (sals_end.nelts > 1)
	    {
	      ambiguous_line_spec (&sals_end);
	      free (sals_end.sals);
	      return;
	    }
	  sal_end = sals_end.sals[0];
	  free (sals_end.sals);
	}
    }

  if (*arg1)
    error ("Junk at end of line specification.");

  if (!no_end && !dummy_beg && !dummy_end
      && sal.symtab != sal_end.symtab)
    error ("Specified start and end are in different files.");
  if (dummy_beg && dummy_end)
    error ("Two empty args do not say what lines to list.");
 
  /* if line was specified by address,
     first print exactly which line, and which file.
     In this case, sal.symtab == 0 means address is outside
     of all known source files, not that user failed to give a filename.  */
  if (*arg == '*')
    {
      if (sal.symtab == 0)
	error ("No source file for address %s.", local_hex_string(sal.pc));
      sym = find_pc_function (sal.pc);
      if (sym)
	{
	  printf_filtered ("%s is in ", local_hex_string(sal.pc));
	  fprint_symbol (stdout, SYMBOL_NAME (sym));
	  printf_filtered (" (%s:%d).\n", sal.symtab->filename, sal.line);
	}
      else
	printf_filtered ("%s is at %s:%d.\n",
			 local_hex_string(sal.pc), 
			 sal.symtab->filename, sal.line);
    }

  /* If line was not specified by just a line number,
     and it does not imply a symtab, it must be an undebuggable symbol
     which means no source code.  */

  if (! linenum_beg && sal.symtab == 0)
    error ("No line number known for %s.", arg);

  /* If this command is repeated with RET,
     turn it into the no-arg variant.  */

  if (from_tty)
    *arg = 0;

  if (dummy_beg && sal_end.symtab == 0)
    error ("No default source file yet.  Do \"help list\".");
  if (dummy_beg)
    print_source_lines (sal_end.symtab,
			max (sal_end.line - (lines_to_list - 1), 1),
			sal_end.line + 1, 0);
  else if (sal.symtab == 0)
    error ("No default source file yet.  Do \"help list\".");
  else if (no_end)
    print_source_lines (sal.symtab,
			max (sal.line - (lines_to_list / 2), 1),
			sal.line + (lines_to_list / 2), 0);
  else
    print_source_lines (sal.symtab, sal.line,
			(dummy_end
			 ? sal.line + lines_to_list
			 : sal_end.line + 1),
			0);
}

/* Print info on range of pc's in a specified line.  */

static void
line_info (arg, from_tty)
     char *arg;
     int from_tty;
{
  struct symtabs_and_lines sals;
  struct symtab_and_line sal;
  CORE_ADDR start_pc, end_pc;
  int i;

  if (arg == 0)
    {
      sal.symtab = current_source_symtab;
      sal.line = last_line_listed;
      sals.nelts = 1;
      sals.sals = (struct symtab_and_line *)
	xmalloc (sizeof (struct symtab_and_line));
      sals.sals[0] = sal;
    }
  else
    {
      sals = decode_line_spec_1 (arg, 0);
      
      /* If this command is repeated with RET,
	 turn it into the no-arg variant.  */
      if (from_tty)
	*arg = 0;
    }

  /* C++  More than one line may have been specified, as when the user
     specifies an overloaded function name. Print info on them all. */
  for (i = 0; i < sals.nelts; i++)
    {
      sal = sals.sals[i];
      
      if (sal.symtab == 0)
	error ("No source file specified.");

      if (sal.line > 0
	  && find_line_pc_range (sal.symtab, sal.line, &start_pc, &end_pc))
	{
	  if (start_pc == end_pc)
	    printf_filtered ("Line %d of \"%s\" is at pc %s but contains no code.\n",
			     sal.line, sal.symtab->filename, local_hex_string(start_pc));
	  else
	    {
	      printf_filtered ("Line %d of \"%s\" starts at pc %s",
			       sal.line, sal.symtab->filename, 
			       local_hex_string(start_pc));
	      printf_filtered (" and ends at %s.\n",
			       local_hex_string(end_pc));
	    }
	  /* x/i should display this line's code.  */
	  set_next_address (start_pc);
	  /* Repeating "info line" should do the following line.  */
	  last_line_listed = sal.line + 1;
	}
      else
	printf_filtered ("Line number %d is out of range for \"%s\".\n",
			 sal.line, sal.symtab->filename);
    }
}

/* Commands to search the source file for a regexp.  */

/* ARGSUSED */
static void
forward_search_command (regex, from_tty)
     char *regex;
     int from_tty;
{
  register int c;
  register int desc;
  register FILE *stream;
  int line = last_line_listed + 1;
  char *msg;

  msg = (char *) re_comp (regex);
  if (msg)
    error (msg);

  if (current_source_symtab == 0)
    select_source_symtab (0);

  /* Search from last_line_listed+1 in current_source_symtab */

  desc = open_source_file (current_source_symtab);
  if (desc < 0)
    perror_with_name (current_source_symtab->filename);

  if (current_source_symtab->line_charpos == 0)
    find_source_lines (current_source_symtab, desc);

  if (line < 1 || line > current_source_symtab->nlines)
    {
      close (desc);
      error ("Expression not found");
    }

  if (lseek (desc, current_source_symtab->line_charpos[line - 1], 0) < 0)
    {
      close (desc);
      perror_with_name (current_source_symtab->filename);
    }

  stream = fdopen (desc, "r");
  clearerr (stream);
  while (1) {
/* FIXME!!!  We walk right off the end of buf if we get a long line!!! */
    char buf[4096];		/* Should be reasonable??? */
    register char *p = buf;

    c = getc (stream);
    if (c == EOF)
      break;
    do {
      *p++ = c;
    } while (c != '\n' && (c = getc (stream)) >= 0);

    /* we now have a source line in buf, null terminate and match */
    *p = 0;
    if (re_exec (buf) > 0)
      {
	/* Match! */
	fclose (stream);
	print_source_lines (current_source_symtab,
			   line, line+1, 0);
	current_source_line = max (line - lines_to_list / 2, 1);
	return;
      }
    line++;
  }

  printf_filtered ("Expression not found\n");
  fclose (stream);
}

/* ARGSUSED */
static void
reverse_search_command (regex, from_tty)
     char *regex;
     int from_tty;
{
  register int c;
  register int desc;
  register FILE *stream;
  int line = last_line_listed - 1;
  char *msg;

  msg = (char *) re_comp (regex);
  if (msg)
    error (msg);

  if (current_source_symtab == 0)
    select_source_symtab (0);

  /* Search from last_line_listed-1 in current_source_symtab */

  desc = open_source_file (current_source_symtab);
  if (desc < 0)
    perror_with_name (current_source_symtab->filename);

  if (current_source_symtab->line_charpos == 0)
    find_source_lines (current_source_symtab, desc);

  if (line < 1 || line > current_source_symtab->nlines)
    {
      close (desc);
      error ("Expression not found");
    }

  if (lseek (desc, current_source_symtab->line_charpos[line - 1], 0) < 0)
    {
      close (desc);
      perror_with_name (current_source_symtab->filename);
    }

  stream = fdopen (desc, "r");
  clearerr (stream);
  while (line > 1)
    {
/* FIXME!!!  We walk right off the end of buf if we get a long line!!! */
      char buf[4096];		/* Should be reasonable??? */
      register char *p = buf;

      c = getc (stream);
      if (c == EOF)
	break;
      do {
	*p++ = c;
      } while (c != '\n' && (c = getc (stream)) >= 0);

      /* We now have a source line in buf; null terminate and match.  */
      *p = 0;
      if (re_exec (buf) > 0)
	{
	  /* Match! */
	  fclose (stream);
	  print_source_lines (current_source_symtab,
			      line, line+1, 0);
	  current_source_line = max (line - lines_to_list / 2, 1);
	  return;
	}
      line--;
      if (fseek (stream, current_source_symtab->line_charpos[line - 1], 0) < 0)
	{
	  fclose (stream);
	  perror_with_name (current_source_symtab->filename);
	}
    }

  printf_filtered ("Expression not found\n");
  fclose (stream);
  return;
}

void
_initialize_source ()
{
  current_source_symtab = 0;
  init_source_path ();

  add_com ("directory", class_files, directory_command,
	   "Add directory DIR to beginning of search path for source files.\n\
Forget cached info on source file locations and line positions.\n\
DIR can also be $cwd for the current working directory, or $cdir for the\n\
directory in which the source file was compiled into object code.\n\
With no argument, reset the search path to $cdir:$cwd, the default.");

  add_cmd ("directories", no_class, show_directories,
	   "Current search path for finding source files.\n\
$cwd in the path means the current working directory.\n\
$cdir in the path means the compilation directory of the source file.",
	   &showlist);

  add_info ("source", source_info,
	    "Information about the current source file.");

  add_info ("line", line_info,
	    "Core addresses of the code for a source line.\n\
Line can be specified as\n\
  LINENUM, to list around that line in current file,\n\
  FILE:LINENUM, to list around that line in that file,\n\
  FUNCTION, to list around beginning of that function,\n\
  FILE:FUNCTION, to distinguish among like-named static functions.\n\
Default is to describe the last source line that was listed.\n\n\
This sets the default address for \"x\" to the line's first instruction\n\
so that \"x/i\" suffices to start examining the machine code.\n\
The address is also stored as the value of \"$_\".");

  add_com ("forward-search", class_files, forward_search_command,
	   "Search for regular expression (see regex(3)) from last line listed.");
  add_com_alias ("search", "forward-search", class_files, 0);

  add_com ("reverse-search", class_files, reverse_search_command,
	   "Search backward for regular expression (see regex(3)) from last line listed.");

  add_com ("list", class_files, list_command,
	   "List specified function or line.\n\
With no argument, lists ten more lines after or around previous listing.\n\
\"list -\" lists the ten lines before a previous ten-line listing.\n\
One argument specifies a line, and ten lines are listed around that line.\n\
Two arguments with comma between specify starting and ending lines to list.\n\
Lines can be specified in these ways:\n\
  LINENUM, to list around that line in current file,\n\
  FILE:LINENUM, to list around that line in that file,\n\
  FUNCTION, to list around beginning of that function,\n\
  FILE:FUNCTION, to distinguish among like-named static functions.\n\
  *ADDRESS, to list around the line containing that address.\n\
With two args if one is empty it stands for ten lines away from the other arg.");
  add_com_alias ("l", "list", class_files, 1);

  add_show_from_set
    (add_set_cmd ("listsize", class_support, var_uinteger,
		  (char *)&lines_to_list,
	"Set number of source lines gdb will list by default.",
		  &setlist),
     &showlist);

  add_com ("setfile", class_files, setfile_command,
	   "Select current file, function and line for display or list.\n\
Specification can have the form:\n\
  LINENUM, to select that line in current file,\n\
  FILE:LINENUM, to select that line in that file,\n\
  FUNCTION, to select beginning of that function,\n\
  FILE:FUNCTION, to distinguish among like-named static functions.\n\
  *ADDRESS, to select the line containing that address.");
  add_com ("push-to-file", class_files, push_to_file_command,
	   "Like \"file\" command but remembers current file & line on a stack.\n\
Can later return to current file with \"pop-file\" command.\n\
Up to 32 file positions can be pushed on stack.");
  add_com ("pop-file", class_files, pop_file_command,
	   "Pops back to file position saved by most recent \"push-to-file\".\n\
If everything has been popped from stack, command does nothing.");

}