[PATCH v4 2/9] Explicit locations: introduce new struct event_location-based API

Keith Seitz
2015-05-07T18:05:55Z

This patch introduces the new breakpoint/"linespec" API based on
a new struct event_location. This API currently only supports
traditional linespecs, maintaining the status quo of the code base.
Future patches will add additional functionality for other location
types such as address locations.

gdb/ChangeLog:

* Makefile.in (SFILES): Add location.c.
(HFILES_NO_SRCDIR): Add location.h.
(COMMON_OBS): Add location.o.
* linespec.c (linespec_lex_to_end): New function.
* linespec.c (linespec_lex_to_end): Declare.
* location.c: New file.
* location.h: New file.
---
gdb/Makefile.in | 6 +
gdb/linespec.c | 55 +++++++++++++
gdb/linespec.h | 5 +
gdb/location.c | 234 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/location.h | 113 +++++++++++++++++++++++++++
5 files changed, 410 insertions(+), 3 deletions(-)
create mode 100644 gdb/location.c
create mode 100644 gdb/location.h

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 95104ef..0a51564 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -851,7 +851,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
inline-frame.c \
interps.c \
jv-exp.y jv-lang.c jv-valprint.c jv-typeprint.c jv-varobj.c \
- language.c linespec.c minidebug.c \
+ language.c linespec.c location.c minidebug.c \
m2-exp.y m2-lang.c m2-typeprint.c m2-valprint.c \
macrotab.c macroexp.c macrocmd.c macroscope.c main.c maint.c \
mdebugread.c memattr.c mem-break.c minsyms.c mipsread.c memory-map.c \
@@ -937,7 +937,7 @@ mi/mi-out.h mi/mi-main.h mi/mi-common.h mi/mi-cmds.h linux-nat.h \
complaints.h gdb_proc_service.h gdb_regex.h xtensa-tdep.h inf-loop.h \
common/gdb_wait.h common/gdb_assert.h solib.h ppc-tdep.h cp-support.h glibc-tdep.h \
interps.h auxv.h gdbcmd.h tramp-frame.h mipsnbsd-tdep.h \
-amd64-linux-tdep.h linespec.h i387-tdep.h mn10300-tdep.h \
+amd64-linux-tdep.h linespec.h location.h i387-tdep.h mn10300-tdep.h \
sparc64-tdep.h monitor.h ppcobsd-tdep.h srec.h \
coff-pe-read.h parser-defs.h gdb_ptrace.h mips-linux-tdep.h \
m68k-tdep.h spu-tdep.h jv-lang.h environ.h amd64-tdep.h \
@@ -1021,7 +1021,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
source.o value.o eval.o valops.o valarith.o valprint.o printcmd.o \
block.o symtab.o psymtab.o symfile.o symfile-debug.o symmisc.o \
linespec.o dictionary.o \
- infcall.o \
+ location.o infcall.o \
infcmd.o infrun.o \
expprint.o environ.o stack.o thread.o \
exceptions.o \
diff --git a/gdb/linespec.c b/gdb/linespec.c
index d2089b5..a480be1 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -2435,6 +2435,61 @@ linespec_parser_delete (void *arg)
linespec_state_destructor (PARSER_STATE (parser));
}

+/* See description in linespec.h. */
+
+void
+linespec_lex_to_end (char **stringp)
+{
+ linespec_parser parser;
+ struct cleanup *cleanup;
+ linespec_token token;
+ volatile struct gdb_exception e;
+ const char *orig;
+
+ if (stringp == NULL || *stringp == NULL)
+ return;
+
+ linespec_parser_new (&parser, 0, current_language, NULL, 0, NULL);
+ cleanup = make_cleanup (linespec_parser_delete, &parser);
+ parser.lexer.saved_arg = *stringp;
+ PARSER_STREAM (&parser) = orig = *stringp;
+
+ TRY
+ {
+ do
+ {
+ /* Stop before any comma tokens; we need it to keep it
+ as the next token in the string. */
+ token = linespec_lexer_peek_token (&parser);
+ if (token.type == LSTOKEN_COMMA)
+ break;
+
+ /* For addresses advance the parser stream past
+ any parsed input and stop lexing. */
+ if (token.type == LSTOKEN_STRING
+ && *LS_TOKEN_STOKEN (token).ptr == '*')
+ {
+ const char *arg;
+
+ arg = *stringp;
+ (void) linespec_expression_to_pc (&arg);
+ PARSER_STREAM (&parser) = arg;
+ break;
+ }
+
+ token = linespec_lexer_consume_token (&parser);
+ }
+ while (token.type != LSTOKEN_EOI && token.type != LSTOKEN_KEYWORD);
+ }
+ CATCH (e, RETURN_MASK_ERROR)
+ {
+ }
+ END_CATCH
+
+ *stringp += PARSER_STREAM (&parser) - orig;
+ do_cleanups (cleanup);
+}
+
/* See linespec.h. */

void
diff --git a/gdb/linespec.h b/gdb/linespec.h
index 7e66024..77ec46d 100644
--- a/gdb/linespec.h
+++ b/gdb/linespec.h
@@ -156,4 +156,9 @@ extern struct symtabs_and_lines decode_line_with_last_displayed (char *, int);
the keyword. If not, return NULL. */

extern const char *linespec_lexer_lex_keyword (const char *p);
+
+/* Find the end of the (first) linespec pointed to by *STRINGP.
+ STRINGP will be advanced to this point. */
+
+extern void linespec_lex_to_end (char **stringp);
#endif /* defined (LINESPEC_H) */
diff --git a/gdb/location.c b/gdb/location.c
new file mode 100644
index 0000000..39e09c1
--- /dev/null
+++ b/gdb/location.c
@@ -0,0 +1,234 @@
+/* Data structures and API for event locations in GDB.
+ Copyright (C) 2013-2015 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 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/>. */
+
+#include "defs.h"
+#include "gdb_assert.h"
+#include "location.h"
+#include "symtab.h"
+#include "language.h"
+#include "linespec.h"
+#include "cli/cli-utils.h"
+#include "probe.h"
+
+#include <ctype.h>
+#include <string.h>
+
+/* An event location used to set a stop event in the inferior.
+ This structure is an amalgam of the various ways
+ to specify where a stop event should be set. */
+
+struct event_location
+{
+ /* The type of this breakpoint specification. */
+ enum event_location_type type;
+#define EL_TYPE(PTR) (PTR)->type
+
+ union
+ {
+ /* A generic "this is a string specification" for a location.
+ This representation is used by both "normal" linespecs and
+ probes. */
+ char *addr_string;
+#define EL_LINESPEC(PTR) ((PTR)->u.addr_string)
+ } u;
+
+ /* Cached string representation of this location. This is used, e.g., to
+ save stop event locations to file. Malloc'd. */
+ char *as_string;
+#define EL_STRING(PTR) ((PTR)->as_string)
+};
+
+/* See description in location.h. */
+
+enum event_location_type
+event_location_type (const struct event_location *location)
+{
+ return EL_TYPE (location);
+}
+
+/* See description in location.h. */
+
+struct event_location *
+new_linespec_location (char **linespec)
+{
+ struct event_location *location;
+
+ location = XCNEW (struct event_location);
+ EL_TYPE (location) = LINESPEC_LOCATION;
+ if (*linespec != NULL)
+ {
+ char *p;
+ char *orig = *linespec;
+
+ linespec_lex_to_end (linespec);
+ p = remove_trailing_whitespace (orig, *linespec);
+ if ((p - orig) > 0)
+ EL_LINESPEC (location) = savestring (orig, p - orig);
+ }
+ return location;
+}
+
+/* See description in location.h. */
+
+const char *
+get_linespec_location (const struct event_location *location)
+{
+ gdb_assert (EL_TYPE (location) == LINESPEC_LOCATION);
+ return EL_LINESPEC (location);
+}
+
+/* See description in location.h. */
+
+struct event_location *
+copy_event_location (const struct event_location *src)
+{
+ struct event_location *dst;
+
+ dst = XCNEW (struct event_location);
+ EL_TYPE (dst) = EL_TYPE (src);
+ if (EL_STRING (src) != NULL)
+ EL_STRING (dst) = xstrdup (EL_STRING (src));
+
+ switch (EL_TYPE (src))
+ {
+ case LINESPEC_LOCATION:
+ if (EL_LINESPEC (src) != NULL)
+ EL_LINESPEC (dst) = xstrdup (EL_LINESPEC (src));
+ break;
+
+ default:
+ gdb_assert_not_reached ("unknown event location type");
+ }
+
+ return dst;
+}
+
+/* A cleanup function for struct event_location. */
+
+static void
+delete_event_location_cleanup (void *data)
+{
+ struct event_location *location = (struct event_location *) data;
+
+ delete_event_location (location);
+}
+
+/* See description in location.h. */
+
+struct cleanup *
+make_cleanup_delete_event_location (struct event_location *location)
+{
+ return make_cleanup (delete_event_location_cleanup, location);
+}
+
+/* See description in location.h. */
+
+void
+delete_event_location (struct event_location *location)
+{
+ if (location != NULL)
+ {
+ xfree (EL_STRING (location));
+
+ switch (EL_TYPE (location))
+ {
+ case LINESPEC_LOCATION:
+ xfree (EL_LINESPEC (location));
+ break;
+
+ default:
+ gdb_assert_not_reached ("unknown event location type");
+ }
+
+ xfree (location);
+ }
+}
+
+/* See description in location.h. */
+
+char *
+event_location_to_string_const (const struct event_location *location)
+{
+ char *result = NULL;
+
+ if (EL_STRING (location) != NULL)
+ return xstrdup (EL_STRING (location));
+
+ switch (EL_TYPE (location))
+ {
+ case LINESPEC_LOCATION:
+ if (EL_LINESPEC (location) != NULL)
+ result = xstrdup (EL_LINESPEC (location));
+ break;
+
+ default:
+ gdb_assert_not_reached ("unknown event location type");
+ }
+
+ return result;
+}
+
+/* See description in location.h. */
+
+const char *
+event_location_to_string (struct event_location *location)
+{
+ /* Cache a copy of the string representation. */
+ if (EL_STRING (location) == NULL)
+ EL_STRING (location) = event_location_to_string_const (location);
+
+ return EL_STRING (location);
+}
+
+/* See description in location.h. */
+
+struct event_location *
+string_to_event_location (char **stringp,
+ const struct language_defn *language)
+{
+ struct event_location *location;
+
+ location = new_linespec_location (stringp);
+ return location;
+}
+
+/* See description in location.h. */
+
+int
+event_location_empty_p (const struct event_location *location)
+{
+ switch (EL_TYPE (location))
+ {
+ case LINESPEC_LOCATION:
+ /* Linespecs are never "empty." (NULL is a valid linespec) */
+ return 0;
+
+ default:
+ gdb_assert_not_reached ("unknown event location type");
+ }
+}
+
+/* See description in location.h. */
+
+void
+set_event_location_string (struct event_location *location,
+ const char *string)
+{
+ xfree (EL_STRING (location));
+ EL_STRING (location) = string == NULL ? NULL : xstrdup (string);
+}
diff --git a/gdb/location.h b/gdb/location.h
new file mode 100644
index 0000000..992f21e
--- /dev/null
+++ b/gdb/location.h
@@ -0,0 +1,113 @@
+/* Data structures and API for event locations in GDB.
+ Copyright (C) 2013-2015 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 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/>. */
+
+#ifndef LOCATIONS_H
+#define LOCATIONS_H 1
+
+struct language_defn;
+struct event_location;
+
+/* An enumeration of the various ways to specify a stop event
+ location (used with create_breakpoint). */
+
+enum event_location_type
+{
+ /* A traditional linespec. */
+ LINESPEC_LOCATION
+};
+
+/* Return the type of the given event location. */
+
+extern enum event_location_type
+ event_location_type (const struct event_location *);
+
+/* Return a string representation of the LOCATION.
+ This function may return NULL for unspecified linespecs,
+ e.g, LOCATION_LINESPEC and addr_string is NULL.
+
+ The result is cached in LOCATION. */
+
+extern const char *
+ event_location_to_string (struct event_location *location);
+
+/* A const version of event_location_to_string that will not cache
+ the resulting string representation. The result is malloc'd
+ and must be freed by the caller. */
+
+extern char *
+ event_location_to_string_const (const struct event_location *location);
+
+/* Create a new linespec location. The return result is malloc'd
+ and should be freed with delete_event_location. */
+
+extern struct event_location *
+ new_linespec_location (char **linespec);
+
+/* Return the linespec location (a string) of the given event_location
+ (which must be of type LINESPEC_LOCATION). */
+
+extern const char *
+ get_linespec_location (const struct event_location *location);
+
+/* Free an event location and any associated data. */
+
+extern void delete_event_location (struct event_location *location);
+
+/* Make a cleanup to free LOCATION. */
+
+extern struct cleanup *
+ make_cleanup_delete_event_location (struct event_location *location);
+
+/* Return a copy of the given SRC location. */
+
+extern struct event_location *
+ copy_event_location (const struct event_location *src);
+
+/* Allocate and "copy" the opaque struct event_location. This is used
+ when decoding locations which must parse their inputs. The return result
+ should be freed. */
+
+extern struct event_location *
+ copy_event_location_tmp (const struct event_location *src);
+
+/* Attempt to convert the input string in *ARGP into an event location.
+ ARGP is advanced past any processed input. Returns a event_location
+ (malloc'd) if an event location was successfully found in *ARGP,
+ NULL otherwise.
+
+ This function may call error() if *ARGP looks like properly formed,
+ but invalid, input, e.g., if it is called with missing argument parameters
+ or invalid options.
+
+ The return result must be freed with delete_event_location. */
+
+extern struct event_location *
+ string_to_event_location (char **argp,
+ const struct language_defn *langauge);
+
+/* A convenience function for testing for unset locations. */
+
+extern int event_location_empty_p (const struct event_location *location);
+
+/* Set the location's string representation. If STRING is NULL, clear
+ the string representation. */
+
+extern void
+ set_event_location_string (struct event_location *location,
+ const char *string);
+#endif /* LOCATIONS_H */