perf tools: Make options always available, even if required libs not linked

This patch keeps options of perf builtins same in all conditions. If
one option is disabled because of compiling options, users should be
notified.

Masami suggested another implementation in [1] that, by adding a
OPTION_NEXT_DEPENDS option before those options in the 'struct option'
array, options parser knows an option is disabled. However, in some
cases this array is reordered (options__order()). In addition, in
parse-option.c that array is const, so we can't simply merge
information in decorator option into the affacted option.

This patch chooses a simpler implementation that, introducing a
set_option_nobuild() function and two option parsing flags. Builtins
with such options should call set_option_nobuild() before option
parsing. The complexity of this patch is because we want some of options
can be skipped safely. In this case their arguments should also be
consumed.

Options in 'perf record' and 'perf probe' are fixed in this patch.

[1] http://lkml.kernel.org/g/[e-mail]

Test result:

Normal case:

# ./perf probe --vmlinux /tmp/vmlinux sys_write
Added new event:
probe:sys_write (on sys_write)

You can now use it in all perf tools, such as:

perf record -e probe:sys_write -aR sleep 1

Build with NO_DWARF=1:

# ./perf probe -L sys_write
Error: switch `L' is not available because NO_DWARF=1

Usage: perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]
or: perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]
or: perf probe [<options>] --del '[GROUP:]EVENT' ...
or: perf probe --list [GROUP:]EVENT ...
or: perf probe [<options>] --funcs

-L, --line <FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]>
Show source code lines.
(not built-in because NO_DWARF=1)

# ./perf probe -k /tmp/vmlinux sys_write
Warning: switch `k' is being ignored because NO_DWARF=1
Added new event:
probe:sys_write (on sys_write)

You can now use it in all perf tools, such as:

perf record -e probe:sys_write -aR sleep 1

# ./perf probe --vmlinux /tmp/vmlinux sys_write
Warning: option `vmlinux' is being ignored because NO_DWARF=1
Added new event:
[SNIP]

# ./perf probe -l
Usage: perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]
or: perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]
...
-k, --vmlinux <file> vmlinux pathname
(not built-in because NO_DWARF=1)
-L, --line <FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]>
Show source code lines.
(not built-in because NO_DWARF=1)
...
-V, --vars <FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT>
Show accessible variables on PROBEDEF
(not built-in because NO_DWARF=1)
--externs Show external variables too (with --vars only)
(not built-in because NO_DWARF=1)
--no-inlines Don't search inlined functions
(not built-in because NO_DWARF=1)
--range Show variables location range in scope (with --vars only)
(not built-in because NO_DWARF=1)

Signed-off-by: Wang Nan <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Zefan Li <[e-mail]>
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-probe.c

···
 
 	return ret;
 }
+#else
+# define opt_show_lines NULL
+# define opt_show_vars NULL
 #endif
 static int opt_add_probe_event(const struct option *opt,
 			      const char *str, int unset __maybe_unused)
···
 		opt_add_probe_event),
 	OPT_BOOLEAN('f', "force", &probe_conf.force_add, "forcibly add events"
 		    " with existing name"),
-#ifdef HAVE_DWARF_SUPPORT
 	OPT_CALLBACK('L', "line", NULL,
 		     "FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]",
 		     "Show source code lines.", opt_show_lines),
···
 		   "directory", "path to kernel source"),
 	OPT_BOOLEAN('\0', "no-inlines", &probe_conf.no_inlines,
 		"Don't search inlined functions"),
-#endif
 	OPT__DRY_RUN(&probe_event_dry_run),
 	OPT_INTEGER('\0', "max-probes", &probe_conf.max_probes,
 		 "Set how many probe points can be found for a probe."),
···
 #ifdef HAVE_DWARF_SUPPORT
 	set_option_flag(options, 'L', "line", PARSE_OPT_EXCLUSIVE);
 	set_option_flag(options, 'V', "vars", PARSE_OPT_EXCLUSIVE);
+#else
+# define set_nobuild(s, l, c) set_option_nobuild(options, s, l, "NO_DWARF=1", c)
+	set_nobuild('L', "line", false);
+	set_nobuild('V', "vars", false);
+	set_nobuild('\0', "externs", false);
+	set_nobuild('\0', "range", false);
+	set_nobuild('k', "vmlinux", true);
+	set_nobuild('s', "source", true);
+	set_nobuild('\0', "no-inlines", true);
+# undef set_nobuild
 #endif
 	set_option_flag(options, 'F', "funcs", PARSE_OPT_EXCLUSIVE);
 

tools/perf/builtin-record.c

···
 			"per thread proc mmap processing timeout in ms"),
 	OPT_BOOLEAN(0, "switch-events", &record.opts.record_switch_events,
 		    "Record context switch events"),
-#ifdef HAVE_LIBBPF_SUPPORT
 	OPT_STRING(0, "clang-path", &llvm_param.clang_path, "clang path",
 		   "clang binary to use for compiling BPF scriptlets"),
 	OPT_STRING(0, "clang-opt", &llvm_param.clang_opt, "clang options",
 		   "options passed to clang when compiling BPF scriptlets"),
-#endif
 	OPT_END()
 };
 
···
 	int err;
 	struct record *rec = &record;
 	char errbuf[BUFSIZ];
+
+#ifndef HAVE_LIBBPF_SUPPORT
+# define set_nobuild(s, l, c) set_option_nobuild(record_options, s, l, "NO_LIBBPF=1", c)
+	set_nobuild('\0', "clang-path", true);
+	set_nobuild('\0', "clang-opt", true);
+# undef set_nobuild
+#endif
 
 	rec->evlist = perf_evlist__new();
 	if (rec->evlist == NULL)

tools/perf/util/parse-options.c

···
 	return error("option `%s' %s", opt->long_name, reason);
 }
 
+static void optwarning(const struct option *opt, const char *reason, int flags)
+{
+	if (flags & OPT_SHORT)
+		warning("switch `%c' %s", opt->short_name, reason);
+	else if (flags & OPT_UNSET)
+		warning("option `no-%s' %s", opt->long_name, reason);
+	else
+		warning("option `%s' %s", opt->long_name, reason);
+}
+
 static int get_arg(struct parse_opt_ctx_t *p, const struct option *opt,
 		   int flags, const char **arg)
 {
+	const char *res;
+
 	if (p->opt) {
-		*arg = p->opt;
+		res = p->opt;
 		p->opt = NULL;
 	} else if ((opt->flags & PARSE_OPT_LASTARG_DEFAULT) && (p->argc == 1 ||
 		    **(p->argv + 1) == '-')) {
-		*arg = (const char *)opt->defval;
+		res = (const char *)opt->defval;
 	} else if (p->argc > 1) {
 		p->argc--;
-		*arg = *++p->argv;
+		res = *++p->argv;
 	} else
 		return opterror(opt, "requires a value", flags);
+	if (arg)
+		*arg = res;
 	return 0;
 }
 
···
 		default:
 			break;
 		}
+	}
+
+	if (opt->flags & PARSE_OPT_NOBUILD) {
+		char reason[128];
+		bool noarg = false;
+
+		err = snprintf(reason, sizeof(reason),
+				opt->flags & PARSE_OPT_CANSKIP ?
+					"is being ignored because %s " :
+					"is not available because %s",
+				opt->build_opt);
+		reason[sizeof(reason) - 1] = '\0';
+
+		if (err < 0)
+			strncpy(reason, opt->flags & PARSE_OPT_CANSKIP ?
+					"is being ignored" :
+					"is not available",
+					sizeof(reason));
+
+		if (!(opt->flags & PARSE_OPT_CANSKIP))
+			return opterror(opt, reason, flags);
+
+		err = 0;
+		if (unset)
+			noarg = true;
+		if (opt->flags & PARSE_OPT_NOARG)
+			noarg = true;
+		if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
+			noarg = true;
+
+		switch (opt->type) {
+		case OPTION_BOOLEAN:
+		case OPTION_INCR:
+		case OPTION_BIT:
+		case OPTION_SET_UINT:
+		case OPTION_SET_PTR:
+		case OPTION_END:
+		case OPTION_ARGUMENT:
+		case OPTION_GROUP:
+			noarg = true;
+			break;
+		case OPTION_CALLBACK:
+		case OPTION_STRING:
+		case OPTION_INTEGER:
+		case OPTION_UINTEGER:
+		case OPTION_LONG:
+		case OPTION_U64:
+		default:
+			break;
+		}
+
+		if (!noarg)
+			err = get_arg(p, opt, flags, NULL);
+		if (err)
+			return err;
+
+		optwarning(opt, reason, flags);
+		return 0;
 	}
 
 	switch (opt->type) {
···
 		pad = USAGE_OPTS_WIDTH;
 	}
 	fprintf(stderr, "%*s%s\n", pad + USAGE_GAP, "", opts->help);
+	if (opts->flags & PARSE_OPT_NOBUILD)
+		fprintf(stderr, "%*s(not built-in because %s)\n",
+			USAGE_OPTS_WIDTH + USAGE_GAP, "",
+			opts->build_opt);
 }
 
 static int option__cmp(const void *va, const void *vb)
···
 	return 0;
 }
 
-void set_option_flag(struct option *opts, int shortopt, const char *longopt,
-		     int flag)
+static struct option *
+find_option(struct option *opts, int shortopt, const char *longopt)
 {
 	for (; opts->type != OPTION_END; opts++) {
 		if ((shortopt && opts->short_name == shortopt) ||
 		    (opts->long_name && longopt &&
-		     !strcmp(opts->long_name, longopt))) {
-			opts->flags |= flag;
-			break;
-		}
+		     !strcmp(opts->long_name, longopt)))
+			return opts;
 	}
+	return NULL;
+}
+
+void set_option_flag(struct option *opts, int shortopt, const char *longopt,
+		     int flag)
+{
+	struct option *opt = find_option(opts, shortopt, longopt);
+
+	if (opt)
+		opt->flags |= flag;
+	return;
+}
+
+void set_option_nobuild(struct option *opts, int shortopt,
+			const char *longopt,
+			const char *build_opt,
+			bool can_skip)
+{
+	struct option *opt = find_option(opts, shortopt, longopt);
+
+	if (!opt)
+		return;
+
+	opt->flags |= PARSE_OPT_NOBUILD;
+	opt->flags |= can_skip ? PARSE_OPT_CANSKIP : 0;
+	opt->build_opt = build_opt;
 }

tools/perf/util/parse-options.h

···
 	PARSE_OPT_DISABLED = 32,
 	PARSE_OPT_EXCLUSIVE = 64,
 	PARSE_OPT_NOEMPTY  = 128,
+	PARSE_OPT_NOBUILD  = 256,
+	PARSE_OPT_CANSKIP  = 512,
 };
 
 struct option;
···
 	void *value;
 	const char *argh;
 	const char *help;
+	const char *build_opt;
 
 	int flags;
 	parse_opt_cb *callback;
···
 extern const char *parse_options_fix_filename(const char *prefix, const char *file);
 
 void set_option_flag(struct option *opts, int sopt, const char *lopt, int flag);
+void set_option_nobuild(struct option *opts, int shortopt, const char *longopt,
+			const char *build_opt, bool can_skip);
 #endif /* __PERF_PARSE_OPTIONS_H */