Explicit locations: add UI features for CLI

This patch exposes explicit locations to the CLI user.  This enables
users to "explicitly" specify attributes of the breakpoint location
to avoid any ambiguity that might otherwise exist with linespecs.

The general syntax of explicit locations is:
-source SOURCE_FILENAME -line {+-}LINE -function FUNCTION_NAME
-label LABEL_NAME

Option names may be abbreviated, e.g., "-s SOURCE_FILENAME -li 3" and users
may use the completer with either options or values.

gdb/ChangeLog:

	* completer.c: Include location.h.
	(enum match_type): New enum.
	(location_completer): Rename to ...
	(linespec_completer): ... this.
	(collect_explicit_location_matches, backup_text_ptr)
	(explicit_location_completer): New functions.
	(location_completer): "New" function; handle linespec
	and explicit location completions.
	(complete_line_internal): Remove all location completer-specific
	handling.
	* linespec.c (linespec_lexer_lex_keyword, is_ada_operator)
	(find_toplevel_char): Export.
	(linespec_parse_line_offset): Export.
	Issue error if STRING is not numerical.
	(gdb_get_linespec_parser_quote_characters): New function.
	* linespec.h (linespec_parse_line_offset): Declare.
	(get_gdb_linespec_parser_quote_characters): Declare.
	(is_ada_operator): Declare.
	(find_toplevel_char): Declare.
	(linespec_lexer_lex_keyword): Declare.
	* location.c (explicit_to_event_location): New function.
	(explicit_location_lex_one): New function.
	(string_to_explicit_location): New function.
	(string_to_event_location): Handle explicit locations.
	* location.h (explicit_to_event_location): Declare.
	(string_to_explicit_location): Declare.

gdb/testsuite/ChangeLog:

	* gdb.linespec/3explicit.c: New file.
	* gdb.linespec/cpexplicit.cc: New file.
	* gdb.linespec/cpexplicit.exp: New file.
	* gdb.linespec/explicit.c: New file.
	* gdb.linespec/explicit.exp: New file.
	* gdb.linespec/explicit2.c: New file.
	* gdb.linespec/ls-errs.exp: Add explicit location tests.
	* lib/gdb.exp (capture_command_output): Regexp-escape `command'
	before using in the matching pattern.
	Clarify that `prefix' is a regular expression.

1 files changed, 206 insertions, 2 deletions

diff --git a/gdb/location.c b/gdb/location.c
index 3985e5a44f..675c8d988f 100644
--- a/gdb/location.c
+++ b/gdb/location.c
@@ -429,6 +429,196 @@ event_location_to_string (struct event_location *location)
   return EL_STRING (location);
 }
 
+/* A lexer for explicit locations.  This function will advance INP
+   past any strings that it lexes.  Returns a malloc'd copy of the
+   lexed string or NULL if no lexing was done.  */
+
+static char *
+explicit_location_lex_one (const char **inp,
+			   const struct language_defn *language)
+{
+  const char *start = *inp;
+
+  if (*start == '\0')
+    return NULL;
+
+  /* If quoted, skip to the ending quote.  */
+  if (strchr (get_gdb_linespec_parser_quote_characters (), *start))
+    {
+      char quote_char = *start;
+
+      /* If the input is not an Ada operator, skip to the matching
+	 closing quote and return the string.  */
+      if (!(language->la_language == language_ada
+	    && quote_char == '\"' && is_ada_operator (start)))
+	{
+	  const char *end = find_toplevel_char (start + 1, quote_char);
+
+	  if (end == NULL)
+	    error (_("Unmatched quote, %s."), start);
+	  *inp = end + 1;
+	  return savestring (start + 1, *inp - start - 2);
+	}
+    }
+
+  /* If the input starts with '-' or '+', the string ends with the next
+     whitespace or comma.  */
+  if (*start == '-' || *start == '+')
+    {
+      while (*inp[0] != '\0' && *inp[0] != ',' && !isspace (*inp[0]))
+	++(*inp);
+    }
+  else
+    {
+      /* Handle numbers first, stopping at the next whitespace or ','.  */
+      while (isdigit (*inp[0]))
+	++(*inp);
+      if (*inp[0] == '\0' || isspace (*inp[0]) || *inp[0] == ',')
+	return savestring (start, *inp - start);
+
+      /* Otherwise stop at the next occurrence of whitespace, '\0',
+	 keyword, or ','.  */
+      *inp = start;
+      while ((*inp)[0]
+	     && (*inp)[0] != ','
+	     && !(isspace ((*inp)[0])
+		  || linespec_lexer_lex_keyword (&(*inp)[1])))
+	{
+	  /* Special case: C++ operator,.  */
+	  if (language->la_language == language_cplus
+	      && strncmp (*inp, "operator", 8)
+	      && (*inp)[9] == ',')
+	    (*inp) += 9;
+	  ++(*inp);
+	}
+    }
+
+  if (*inp - start > 0)
+    return savestring (start, *inp - start);
+
+  return NULL;
+}
+
+/* See description in location.h.  */
+
+struct event_location *
+string_to_explicit_location (const char **argp,
+			     const struct language_defn *language,
+			     int dont_throw)
+{
+  struct cleanup *cleanup;
+  struct event_location *location;
+
+  /* It is assumed that input beginning with '-' and a non-digit
+     character is an explicit location.  */
+  if (argp == NULL
+      || *argp == '\0'
+      || *argp[0] != '-'
+      || !isalpha ((*argp)[1]))
+    return NULL;
+
+  location = new_explicit_location (NULL);
+  cleanup = make_cleanup_delete_event_location (location);
+
+  /* Process option/argument pairs.  dprintf_command
+     requires that processing stop on ','.  */
+  while ((*argp)[0] != '\0' && (*argp)[0] != ',')
+    {
+      int len;
+      char *opt, *oarg;
+      const char *start;
+      struct cleanup *opt_cleanup, *oarg_cleanup;
+
+      /* If *ARGP starts with a keyword, stop processing
+	 options.  */
+      if (linespec_lexer_lex_keyword (*argp) != NULL)
+	break;
+
+      /* Mark the start of the string in case we need to rewind.  */
+      start = *argp;
+
+      /* Get the option string.  */
+      opt = explicit_location_lex_one (argp, language);
+      opt_cleanup = make_cleanup (xfree, opt);
+
+      *argp = skip_spaces_const (*argp);
+
+      /* Get the argument string.  */
+      oarg = explicit_location_lex_one (argp, language);
+      oarg_cleanup = make_cleanup (xfree, oarg);
+      *argp = skip_spaces_const (*argp);
+
+      /* Use the length of the option to allow abbreviations.  */
+      len = strlen (opt);
+
+      /* All options have a required argument.  Checking for this required
+	 argument is deferred until later.  */
+      if (strncmp (opt, "-source", len) == 0)
+	EL_EXPLICIT (location)->source_filename = oarg;
+      else if (strncmp (opt, "-function", len) == 0)
+	EL_EXPLICIT (location)->function_name = oarg;
+      else if (strncmp (opt, "-line", len) == 0)
+	{
+	  if (oarg != NULL)
+	    {
+	      EL_EXPLICIT (location)->line_offset
+		= linespec_parse_line_offset (oarg);
+	      do_cleanups (oarg_cleanup);
+	      do_cleanups (opt_cleanup);
+	      continue;
+	    }
+	}
+      else if (strncmp (opt, "-label", len) == 0)
+	EL_EXPLICIT (location)->label_name = oarg;
+      /* Only emit an "invalid argument" error for options
+	 that look like option strings.  */
+      else if (opt[0] == '-' && !isdigit (opt[1]))
+	{
+	  if (!dont_throw)
+	    error (_("invalid explicit location argument, \"%s\""), opt);
+	}
+      else
+	{
+	  /* End of the explicit location specification.
+	     Stop parsing and return whatever explicit location was
+	     parsed.  */
+	  *argp = start;
+	  discard_cleanups (oarg_cleanup);
+	  do_cleanups (opt_cleanup);
+	  discard_cleanups (cleanup);
+	  return location;
+	}
+
+      /* It's a little lame to error after the fact, but in this
+	 case, it provides a much better user experience to issue
+	 the "invalid argument" error before any missing
+	 argument error.  */
+      if (oarg == NULL && !dont_throw)
+	error (_("missing argument for \"%s\""), opt);
+
+      /* The option/argument pair was successfully processed;
+	 oarg belongs to the explicit location, and opt should
+	 be freed.  */
+      discard_cleanups (oarg_cleanup);
+      do_cleanups (opt_cleanup);
+    }
+
+  /* One special error check:  If a source filename was given
+     without offset, function, or label, issue an error.  */
+  if (EL_EXPLICIT (location)->source_filename != NULL
+      && EL_EXPLICIT (location)->function_name == NULL
+      && EL_EXPLICIT (location)->label_name == NULL
+      && (EL_EXPLICIT (location)->line_offset.sign == LINE_OFFSET_UNKNOWN)
+      && !dont_throw)
+    {
+      error (_("Source filename requires function, label, or "
+	       "line offset."));
+    }
+
+  discard_cleanups (cleanup);
+  return location;
+}
+
 /* See description in location.h.  */
 
 struct event_location *
@@ -461,8 +651,22 @@ string_to_event_location (char **stringp,
 	}
       else
 	{
-	  /* Everything else is a linespec.  */
-	  location = new_linespec_location (stringp);
+	  const char *arg, *orig;
+
+	  /* Next, try an explicit location.  */
+	  orig = arg = *stringp;
+	  location = string_to_explicit_location (&arg, language, 0);
+	  if (location != NULL)
+	    {
+	      /* It was a valid explicit location.  Advance STRINGP to
+		 the end of input.  */
+	      *stringp += arg - orig;
+	    }
+	  else
+	    {
+	      /* Everything else is a linespec.  */
+	      location = new_linespec_location (stringp);
+	    }
 	}
     }