perf tools: Provide help for subset of options

Some tools have a lot of options, so, providing a way to show help just
for some of them may come handy:

  $ perf report -h --tui

   Usage: perf report [<options>]

        --tui             Use the TUI interface

  $ perf report -h --tui --showcpuutilization -b -c

   Usage: perf report [<options>]

    -b, --branch-stack    use branch records for per branch histogram filling
    -c, --comms <comm[,comm...]>
                          only consider symbols in these comms
        --showcpuutilization
                          Show sample percentage for different cpu modes
        --tui             Use the TUI interface

  $

Using it with perf bash completion is also handy, just make sure you
source the needed file:

  $ . ~/git/linux/tools/perf/perf-completion.sh

Then press tab/tab after -- to see a list of options, put them after -h
and only the options chosen will have its help presented:

  $ perf report -h --
  --asm-raw              --demangle-kernel      --group
  --kallsyms             --pretty               --stdio
  --branch-history       --disassembler-style   --gtk
  --max-stack            --showcpuutilization   --symbol-filter
  --branch-stack         --dsos                 --header
  --mem-mode             --show-info            --symbols
  --call-graph           --dump-raw-trace       --header-only
  --modules              --show-nr-samples      --symfs
  --children             --exclude-other        --hide-unresolved
  --objdump              --show-ref-call-graph  --threads
  --column-widths        --fields               --ignore-callees
  --parent               --show-total-period    --tid
  --comms                --field-separator      --input
  --percentage           --socket-filter        --tui
  --cpu                  --force                --inverted
  --percent-limit        --sort                 --verbose
  --demangle             --full-source-path     --itrace
  --pid                  --source               --vmlinux
  $ perf report -h --socket-filter

   Usage: perf report [<options>]

      --socket-filter <n>
                  only show processor socket that match with this filter

Suggested-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Chandler Carruth <chandlerc@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-83mcdd3wj0379jcgea8w0fxa@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 33 insertions, 9 deletions

diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
index fb26532d67c3..22c2806bda98 100644
--- a/tools/perf/util/parse-options.c
+++ b/tools/perf/util/parse-options.c
@@ -373,7 +373,8 @@ void parse_options_start(struct parse_opt_ctx_t *ctx,
 }
 
 static int usage_with_options_internal(const char * const *,
-                                       const struct option *, int);
+                                       const struct option *, int,
+                                       struct parse_opt_ctx_t *);
 
 int parse_options_step(struct parse_opt_ctx_t *ctx,
                        const struct option *options,
@@ -397,8 +398,9 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 
                 if (arg[1] != '-') {
                         ctx->opt = ++arg;
-                        if (internal_help && *ctx->opt == 'h')
-                                return usage_with_options_internal(usagestr, options, 0);
+                        if (internal_help && *ctx->opt == 'h') {
+                                return usage_with_options_internal(usagestr, options, 0, ctx);
+                        }
                         switch (parse_short_opt(ctx, options)) {
                         case -1:
                                 return parse_options_usage(usagestr, options, arg, 1);
@@ -413,7 +415,7 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
                                 check_typos(arg, options);
                         while (ctx->opt) {
                                 if (internal_help && *ctx->opt == 'h')
-                                        return usage_with_options_internal(usagestr, options, 0);
+                                        return usage_with_options_internal(usagestr, options, 0, ctx);
                                 arg = ctx->opt;
                                 switch (parse_short_opt(ctx, options)) {
                                 case -1:
@@ -446,9 +448,9 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 
                 arg += 2;
                 if (internal_help && !strcmp(arg, "help-all"))
-                        return usage_with_options_internal(usagestr, options, 1);
+                        return usage_with_options_internal(usagestr, options, 1, ctx);
                 if (internal_help && !strcmp(arg, "help"))
-                        return usage_with_options_internal(usagestr, options, 0);
+                        return usage_with_options_internal(usagestr, options, 0, ctx);
                 if (!strcmp(arg, "list-opts"))
                         return PARSE_OPT_LIST_OPTS;
                 if (!strcmp(arg, "list-cmds"))
@@ -682,8 +684,27 @@ out:
         return ordered;
 }
 
+static bool option__in_argv(const struct option *opt, const struct parse_opt_ctx_t *ctx)
+{
+        int i;
+
+        for (i = 1; i < ctx->argc; ++i) {
+                const char *arg = ctx->argv[i];
+
+                if (arg[0] != '-')
+                        continue;
+
+                if (arg[1] == opt->short_name ||
+                    (arg[1] == '-' && opt->long_name && strcmp(opt->long_name, arg + 2) == 0))
+                        return true;
+        }
+
+        return false;
+}
+
 int usage_with_options_internal(const char * const *usagestr,
-                                const struct option *opts, int full)
+                                const struct option *opts, int full,
+                                struct parse_opt_ctx_t *ctx)
 {
         struct option *ordered;
 
@@ -707,8 +728,11 @@ int usage_with_options_internal(const char * const *usagestr,
         if (ordered)
                 opts = ordered;
 
-        for (  ; opts->type != OPTION_END; opts++)
+        for (  ; opts->type != OPTION_END; opts++) {
+                if (ctx && ctx->argc > 1 && !option__in_argv(opts, ctx))
+                        continue;
                 print_option_help(opts, full);
+        }
 
         fputc('\n', stderr);
 
@@ -721,7 +745,7 @@ void usage_with_options(const char * const *usagestr,
                         const struct option *opts)
 {
         exit_browser(false);
-        usage_with_options_internal(usagestr, opts, 0);
+        usage_with_options_internal(usagestr, opts, 0, NULL);
         exit(129);
 }