GDB: Allow arbitrary keywords in integer set commands

Rather than just `unlimited' allow the integer set commands (or command
options) to define arbitrary keywords for the user to use, removing
hardcoded arrangements for the `unlimited' keyword.

Remove the confusingly named `var_zinteger', `var_zuinteger' and
`var_zuinteger_unlimited' `set'/`show' command variable types redefining
them in terms of `var_uinteger', `var_integer' and `var_pinteger', which
have the range of [0;UINT_MAX], [INT_MIN;INT_MAX], and [0;INT_MAX] each.

Following existing practice `var_pinteger' allows extra negative values
to be used, however unlike `var_zuinteger_unlimited' any number of such
values can be defined rather than just `-1'.

The "p" in `var_pinteger' stands for "positive", for the lack of a more
appropriate unambiguous letter, even though 0 obviously is not positive;
"n" would be confusing as to whether it stands for "non-negative" or
"negative".

Add a new structure, `literal_def', the entries of which define extra
keywords allowed for a command and numerical values they correspond to.
Those values are not verified against the basic range supported by the
underlying variable type, allowing extra values to be allowed outside
that range, which may or may not be individually made visible to the
user.  An optional value translation is possible with the structure to
follow the existing practice for some commands where user-entered 0 is
internally translated to UINT_MAX or INT_MAX.  Such translation can now
be arbitrary.  Literals defined by this structure are automatically used
for completion as necessary.

So for example:

const literal_def integer_unlimited_literals[] =
  {
    { "unlimited", INT_MAX, 0 },
    { nullptr }
  };

defines an extra `unlimited' keyword and a user-visible 0 value, both of
which get translated to INT_MAX for the setting to be used with.

Similarly:

const literal_def zuinteger_unlimited_literals[] =
  {
    { "unlimited", -1, -1 },
    { nullptr }
  };

defines the same keyword and a corresponding user-visible -1 value that
is used for the requested setting.  If the last member were omitted (or
set to `{}') here, then only the keyword would be allowed for the user
to enter and while -1 would still be used internally trying to enter it
as a part of a command would result in an "integer -1 out of range"
error.

Use said error message in all cases (citing the invalid value requested)
replacing "only -1 is allowed to set as unlimited" previously used for
`var_zuinteger_unlimited' settings only rather than propagating it to
`var_pinteger' type.  It could only be used for the specific case where
a single extra `unlimited' keyword was defined standing for -1 and the
use of numeric equivalents is discouraged anyway as it is for historical
reasons only that they expose GDB internals, confusingly different
across variable types.  Similarly update the "must be >= -1" Guile error
message.

Redefine Guile and Python parameter types in terms of the new variable
types and interpret extra keywords as Scheme keywords and Python strings
used to communicate corresponding parameter values.  Do not add a new
PARAM_INTEGER Guile parameter type, however do handle the `var_integer'
variable type now, permitting existing parameters defined by GDB proper,
such as `listsize', to be accessed from Scheme code.

With these changes in place it should be trivial for a Scheme or Python
programmer to expand the syntax of the `make-parameter' command and the
`gdb.Parameter' class initializer to have arbitrary extra literals along
with their internal representation supplied.

Update the testsuite accordingly.

Approved-By: Simon Marchi <simon.marchi@efficios.com>

1 files changed, 117 insertions, 130 deletions

diff --git a/gdb/cli/cli-setshow.c b/gdb/cli/cli-setshow.c
index dccf04ee839..dad3e606620 100644
--- a/gdb/cli/cli-setshow.c
+++ b/gdb/cli/cli-setshow.c
@@ -149,10 +149,11 @@ deprecated_show_value_hack (struct ui_file *ignore_file,
     }
 }
 
-/* Returns true if ARG is "unlimited".  */
+/* Returns true and the value in VAL if ARG is an accepted literal.  */
 
 static bool
-is_unlimited_literal (const char **arg, bool expression)
+get_literal_val (LONGEST &val, const literal_def *extra_literals,
+		 const char **arg, bool expression)
 {
   *arg = skip_spaces (*arg);
 
@@ -162,85 +163,104 @@ is_unlimited_literal (const char **arg, bool expression)
 
   size_t len = p - *arg;
 
-  if (len > 0 && strncmp ("unlimited", *arg, len) == 0)
-    {
-      *arg += len;
-
-      /* If parsing an expression (i.e., parsing for a "set" command),
-	 anything after "unlimited" is junk.  For options, anything
-	 after "unlimited" might be a command argument or another
-	 option.  */
-      if (expression)
+  if (len > 0 && extra_literals != nullptr)
+    for (const literal_def *l = extra_literals;
+	 l->literal != nullptr;
+	 l++)
+      if (strncmp (l->literal, *arg, len) == 0)
 	{
-	  const char *after = skip_spaces (*arg);
-	  if (*after != '\0')
-	    error (_("Junk after \"%.*s\": %s"),
-		   (int) len, unl_start, after);
-	}
+	  *arg += len;
 
-      return true;
-    }
+	  /* If parsing an expression (i.e., parsing for a "set" command),
+	     anything after the literal is junk.  For options, anything
+	     after the literal might be a command argument or another
+	     option.  */
+	  if (expression)
+	    {
+	      const char *after = skip_spaces (*arg);
+	      if (*after != '\0')
+		error (_("Junk after \"%.*s\": %s"),
+		       (int) len, unl_start, after);
+	    }
+
+	  val = l->use;
+	  return true;
+	}
 
   return false;
 }
 
 /* See cli-setshow.h.  */
 
-unsigned int
-parse_cli_var_uinteger (var_types var_type, const char **arg,
-			bool expression)
+LONGEST
+parse_cli_var_integer (var_types var_type, const literal_def *extra_literals,
+		       const char **arg, bool expression)
 {
   LONGEST val;
 
   if (*arg == nullptr || **arg == '\0')
     {
-      if (var_type == var_uinteger)
-	error_no_arg (_("integer to set it to, or \"unlimited\""));
-      else
+      if (extra_literals == nullptr)
 	error_no_arg (_("integer to set it to"));
-    }
-
-  if (var_type == var_uinteger && is_unlimited_literal (arg, expression))
-    val = 0;
-  else if (expression)
-    val = parse_and_eval_long (*arg);
-  else
-    val = get_ulongest (arg);
-
-  if (var_type == var_uinteger && val == 0)
-    val = UINT_MAX;
-  else if (val < 0
-	   /* For var_uinteger, don't let the user set the value
-	      to UINT_MAX directly, as that exposes an
-	      implementation detail to the user interface.  */
-	   || (var_type == var_uinteger && val >= UINT_MAX)
-	   || (var_type == var_zuinteger && val > UINT_MAX))
-    error (_("integer %s out of range"), plongest (val));
-
-  return val;
-}
-
-/* See cli-setshow.h.  */
+      else
+	{
+	  std::string buffer = "";
+	  size_t count = 0;
 
-int
-parse_cli_var_zuinteger_unlimited (const char **arg, bool expression)
-{
-  LONGEST val;
+	  for (const literal_def *l = extra_literals;
+	       l->literal != nullptr;
+	       l++, count++)
+	    {
+	      if (count != 0)
+		buffer += ", ";
+	      buffer = buffer + '"' + l->literal + '"';
+	    }
+	  if (count > 1)
+	    error_no_arg
+	      (string_printf (_("integer to set it to, or one of: %s"),
+			      buffer.c_str ()).c_str ());
+	  else
+	    error_no_arg
+	      (string_printf (_("integer to set it to, or %s"),
+			      buffer.c_str ()).c_str ());
+	}
+    }
 
-  if (*arg == nullptr || **arg == '\0')
-    error_no_arg (_("integer to set it to, or \"unlimited\""));
+  if (!get_literal_val (val, extra_literals, arg, expression))
+    {
+      if (expression)
+	val = parse_and_eval_long (*arg);
+      else
+	val = get_ulongest (arg);
 
-  if (is_unlimited_literal (arg, expression))
-    val = -1;
-  else if (expression)
-    val = parse_and_eval_long (*arg);
-  else
-    val = get_ulongest (arg);
+      enum tribool allowed = TRIBOOL_UNKNOWN;
+      if (extra_literals != nullptr)
+	{
+	  for (const literal_def *l = extra_literals;
+	       l->literal != nullptr;
+	       l++)
+	    if (l->val.has_value () && val == *l->val)
+	      {
+		allowed = TRIBOOL_TRUE;
+		val = l->use;
+		break;
+	      }
+	    else if (val == l->use)
+	      allowed = TRIBOOL_FALSE;
+	}
 
-  if (val > INT_MAX)
-    error (_("integer %s out of range"), plongest (val));
-  else if (val < -1)
-    error (_("only -1 is allowed to set as unlimited"));
+      if (allowed == TRIBOOL_UNKNOWN)
+	{
+	  if (val > UINT_MAX || val < INT_MIN
+	      || (var_type == var_uinteger && val < 0)
+	      || (var_type == var_integer && val > INT_MAX)
+	      || (var_type == var_pinteger && val < 0)
+	      || (var_type == var_pinteger && val > INT_MAX))
+	    allowed = TRIBOOL_FALSE;
+	}
+      if (allowed == TRIBOOL_FALSE)
+	error (_("integer %s out of range"), plongest (val));
+    }
 
   return val;
 }
@@ -405,41 +425,18 @@ do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
       option_changed = c->var->set<enum auto_boolean> (parse_auto_binary_operation (arg));
       break;
     case var_uinteger:
-    case var_zuinteger:
       option_changed
-	= c->var->set<unsigned int> (parse_cli_var_uinteger (c->var->type (),
-							     &arg, true));
+	= c->var->set<unsigned int> (parse_cli_var_integer (c->var->type (),
+							    c->var->
+							    extra_literals (),
+							    &arg, true));
       break;
     case var_integer:
-    case var_zinteger:
-      {
-	LONGEST val;
-
-	if (*arg == '\0')
-	  {
-	    if (c->var->type () == var_integer)
-	      error_no_arg (_("integer to set it to, or \"unlimited\""));
-	    else
-	      error_no_arg (_("integer to set it to"));
-	  }
-
-	if (c->var->type () == var_integer && is_unlimited_literal (&arg, true))
-	  val = 0;
-	else
-	  val = parse_and_eval_long (arg);
-
-	if (val == 0 && c->var->type () == var_integer)
-	  val = INT_MAX;
-	else if (val < INT_MIN
-		 /* For var_integer, don't let the user set the value
-		    to INT_MAX directly, as that exposes an
-		    implementation detail to the user interface.  */
-		 || (c->var->type () == var_integer && val >= INT_MAX)
-		 || (c->var->type () == var_zinteger && val > INT_MAX))
-	  error (_("integer %s out of range"), plongest (val));
-
-	option_changed = c->var->set<int> (val);
-      }
+    case var_pinteger:
+      option_changed
+	= c->var->set<int> (parse_cli_var_integer (c->var->type (),
+						   c->var->extra_literals (),
+						   &arg, true));
       break;
     case var_enum:
       {
@@ -454,10 +451,6 @@ do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	option_changed = c->var->set<const char *> (match);
       }
       break;
-    case var_zuinteger_unlimited:
-      option_changed = c->var->set<int>
-	(parse_cli_var_zuinteger_unlimited (&arg, true));
-      break;
     default:
       error (_("gdb internal error: bad var_type in do_setshow_command"));
     }
@@ -551,7 +544,6 @@ do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	  }
 	  break;
 	case var_uinteger:
-	case var_zuinteger:
 	  {
 	    char s[64];
 
@@ -560,8 +552,7 @@ do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
 	  }
 	  break;
 	case var_integer:
-	case var_zinteger:
-	case var_zuinteger_unlimited:
+	case var_pinteger:
 	  {
 	    char s[64];
 
@@ -623,36 +614,32 @@ get_setshow_command_value_string (const setting &var)
 	}
       break;
     case var_uinteger:
-    case var_zuinteger:
-      {
-	const unsigned int value = var.get<unsigned int> ();
-
-	if (var.type () == var_uinteger
-	    && value == UINT_MAX)
-	  stb.puts ("unlimited");
-	else
-	  stb.printf ("%u", value);
-      }
-      break;
     case var_integer:
-    case var_zinteger:
-      {
-	const int value = var.get<int> ();
-
-	if (var.type () == var_integer
-	    && value == INT_MAX)
-	  stb.puts ("unlimited");
-	else
-	  stb.printf ("%d", value);
-      }
-      break;
-    case var_zuinteger_unlimited:
+    case var_pinteger:
       {
-	const int value = var.get<int> ();
-	if (value == -1)
-	  stb.puts ("unlimited");
-	else
-	  stb.printf ("%d", value);
+	bool printed = false;
+	const LONGEST value
+	  = (var.type () == var_uinteger
+	     ? static_cast<LONGEST> (var.get<unsigned int> ())
+	     : static_cast<LONGEST> (var.get<int> ()));
+
+	if (var.extra_literals () != nullptr)
+	  for (const literal_def *l = var.extra_literals ();
+	       l->literal != nullptr;
+	       l++)
+	    if (value == l->use)
+	      {
+		stb.puts (l->literal);
+		printed = true;
+		break;
+	      }
+	if (!printed)
+	  {
+	    if (var.type () == var_uinteger)
+	      stb.printf ("%u", static_cast<unsigned int> (value));
+	    else
+	      stb.printf ("%d", static_cast<int> (value));
+	  }
       }
       break;
     default: