binutils-gdb/gdb/linespec.h
Keith Seitz 0578b14e99 Expand keyword lexing intelligence in the linespec parser.
This patch changes the heuristic the linespec lexer uses to
    detect a keyword in the input stream.

    Currently, the heuristic is: a word is a keyword if it
    1) points to a string that is a keyword
    2) is followed by a non-identifier character

    This is strictly more correct than using whitespace. For example,
    it allows constructs such as "break foo if(i == 1)". However,
    find_condition_and_thread in breakpoint.c does not support this expanded
    usage. It requires whitespace to follow the keyword.

    The proposed new heuristic is: a word is a keyword if it
    1) points to a string that is a keyword
    2) is followed by whitespace
    3) is not followed by another keyword string followed by whitespace

    This additional complexity allows constructs such as
    "break thread thread 3" and "break thread 3".  In the former case,
    the actual location is a symbol named "thread" to be set on thread #3.
    In the later case, the location is NULL, i.e., the default location,
    to be set on thread #3.

    In order to pass all the new tests added here, I've also had to add a
    new feature to parse_breakpoint_sals, which expands recognition of the
    default location to keywords other than "if", which is the only keyword
    currently permitted with the default (NULL) location, but there is no
    reason to exclude other keywords.

    Consequently, it will be possible to use "break thread 1" or
    "break task 1".

    In addition to all of this, it is now possible to remove the keyword_ok
    state from the linespec parser.

    gdb/ChangeLog

    	* breakpoint.c (parse_breakpoint_sals): Use
    	linespec_lexer_lex_keyword to ascertain if the user specified
    	a NULL location.
    	* linespec.c [IF_KEYWORD_INDEX]: Define.
    	(linespec_lexer_lex_keyword): Export.
    	(struct ls_parser) <keyword_ok>: Remove.
    	A keyword is only a keyword if not followed by another keyword.
    	(linespec_lexer_lex_one): Remove keyword_ok handling.
    	Add comment explaining why the parsing stream is not advanced
    	when a keyword is seen.
    	(parse_linespec): Remove parser->keyword_ok.
    	* linespec.h (linespec_lexer_lex_keyword): Add declaration.

    gdb/testsuite/ChangeLog

    	* gdb.linespec/keywords.c: New file.
    	* gdb.linespec/keywords.exp: New file.
2015-03-23 13:16:39 -07:00

160 lines
5.6 KiB
C

/* Header for GDB line completion.
Copyright (C) 2000-2015 Free Software Foundation, Inc.
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 3 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, see <http://www.gnu.org/licenses/>. */
#if !defined (LINESPEC_H)
#define LINESPEC_H 1
struct symtab;
#include "vec.h"
/* Flags to pass to decode_line_1 and decode_line_full. */
enum decode_line_flags
{
/* Set this flag if you want the resulting SALs to describe the
first line of indicated functions. */
DECODE_LINE_FUNFIRSTLINE = 1,
/* Set this flag if you want "list mode". In this mode, a
FILE:LINE linespec will always return a result, and such
linespecs will not be expanded to all matches. */
DECODE_LINE_LIST_MODE = 2
};
/* decode_line_full returns a vector of these. */
struct linespec_sals
{
/* This is the linespec corresponding to the sals contained in this
object. It can be passed as the FILTER argument to future calls
to decode_line_full. This is freed by
destroy_linespec_result. */
char *canonical;
/* Sals. The 'sals' field is destroyed by
destroy_linespec_result. */
struct symtabs_and_lines sals;
};
typedef struct linespec_sals linespec_sals;
DEF_VEC_O (linespec_sals);
/* An instance of this may be filled in by decode_line_1. The caller
must call init_linespec_result to initialize it and
destroy_linespec_result to destroy it. The caller must make copies
of any data that it needs to keep. */
struct linespec_result
{
/* If non-zero, the linespec should be displayed to the user. This
is used by "unusual" linespecs where the ordinary `info break'
display mechanism would do the wrong thing. */
int special_display;
/* If non-zero, the linespec result should be considered to be a
"pre-expanded" multi-location linespec. A pre-expanded linespec
holds all matching locations in a single linespec_sals
object. */
int pre_expanded;
/* If PRE_EXPANDED is non-zero, this is set to the linespec entered
by the user. This will be freed by destroy_linespec_result. */
char *addr_string;
/* The sals. The vector will be freed by
destroy_linespec_result. */
VEC (linespec_sals) *sals;
};
/* Initialize a linespec_result. */
extern void init_linespec_result (struct linespec_result *);
/* Destroy a linespec_result. */
extern void destroy_linespec_result (struct linespec_result *);
/* Return a cleanup that destroys a linespec_result. */
extern struct cleanup *
make_cleanup_destroy_linespec_result (struct linespec_result *);
/* Decode a linespec using the provided default symtab and line. */
extern struct symtabs_and_lines
decode_line_1 (char **argptr, int flags,
struct symtab *default_symtab, int default_line);
/* Parse *ARGPTR as a linespec and return results. This is the "full"
interface to this module, which handles multiple results
properly.
For FLAGS, see decode_line_flags. DECODE_LINE_LIST_MODE is not
valid for this function.
DEFAULT_SYMTAB and DEFAULT_LINE describe the default location.
DEFAULT_SYMTAB can be NULL, in which case the current symtab and
line are used.
CANONICAL is where the results are stored. It must not be NULL.
SELECT_MODE must be one of the multiple_symbols_* constants, or
NULL. It determines how multiple results will be handled. If
NULL, the appropriate CLI value will be used.
FILTER can either be NULL or a string holding a canonical name.
This is only valid when SELECT_MODE is multiple_symbols_all.
Multiple results are handled differently depending on the
arguments:
. With multiple_symbols_cancel, an exception is thrown.
. With multiple_symbols_ask, a menu is presented to the user. The
user may select none, in which case an exception is thrown; or all,
which is handled like multiple_symbols_all, below. Otherwise,
CANONICAL->SALS will have one entry for each name the user chose.
. With multiple_symbols_all, CANONICAL->SALS will have a single
entry describing all the matching locations. If FILTER is
non-NULL, then only locations whose canonical name is equal (in the
strcmp sense) to FILTER will be returned; all others will be
filtered out. */
extern void decode_line_full (char **argptr, int flags,
struct symtab *default_symtab, int default_line,
struct linespec_result *canonical,
const char *select_mode,
const char *filter);
/* Given a string, return the line specified by it, using the current
source symtab and line as defaults.
This is for commands like "list" and "breakpoint". */
extern struct symtabs_and_lines decode_line_with_current_source (char *, int);
/* Given a string, return the line specified by it, using the last displayed
codepoint's values as defaults, or nothing if they aren't valid. */
extern struct symtabs_and_lines decode_line_with_last_displayed (char *, int);
/* Does P represent one of the keywords? If so, return
the keyword. If not, return NULL. */
extern const char *linespec_lexer_lex_keyword (const char *p);
#endif /* defined (LINESPEC_H) */