[PATCH 1/4] perf build: introduce build subcommand

[Aditya Gupta]

Currently the presence of a feature is checked with a combination of
perf version --build-options and greps, such as:

    perf version --build-options | grep " on .* HAVE_FEATURE"

Instead of this, introduce a subcommand "perf build --has", with which
scripts can test for presence of a feature, such as:

    perf build --has HAVE_FEATURE

'perf build --has' command is expected to have exit status of 1 if feature is
built-in, and 0 if not, -2 if feature is not known.

A global array 'supported_features' has also been introduced that can be
used by other commands like 'perf version --build-options', so that
new features can be added in one place, with the array

Signed-off-by: Aditya Gupta <adityag@xxxxxxxxxxxxx>
---
 tools/perf/Build           |  1 +
 tools/perf/builtin-build.c | 94 ++++++++++++++++++++++++++++++++++++++
 tools/perf/builtin.h       | 47 +++++++++++++++++++
 tools/perf/perf.c          |  1 +
 4 files changed, 143 insertions(+)
 create mode 100644 tools/perf/builtin-build.c

diff --git a/tools/perf/Build b/tools/perf/Build
index aa7623622834..b15294919e75 100644
--- a/tools/perf/Build
+++ b/tools/perf/Build
@@ -5,6 +5,7 @@ perf-y += builtin-diff.o
 perf-y += builtin-evlist.o
 perf-y += builtin-ftrace.o
 perf-y += builtin-help.o
+perf-y += builtin-build.o
 perf-y += builtin-buildid-list.o
 perf-y += builtin-buildid-cache.o
 perf-y += builtin-kallsyms.o
diff --git a/tools/perf/builtin-build.c b/tools/perf/builtin-build.c
new file mode 100644
index 000000000000..60af38c3bc64
--- /dev/null
+++ b/tools/perf/builtin-build.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "builtin.h"
+#include "color.h"
+#include "util/debug.h"
+#include "util/header.h"
+#include <tools/config.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <subcmd/parse-options.h>
+
+struct build {
+	const char *has;
+};
+
+static struct build build;
+
+static struct option build_options[] = {
+	OPT_STRING(0, "has", &build.has, NULL, "check if a feature is built in"),
+	OPT_END(),
+};
+
+static const char * const build_usage[] = {
+	"perf build [<options>]",
+	NULL
+};
+
+static void on_off_print(const char *status)
+{
+	printf("[ ");
+
+	if (!strcmp(status, "OFF"))
+		color_fprintf(stdout, PERF_COLOR_RED, "%-3s", status);
+	else
+		color_fprintf(stdout, PERF_COLOR_GREEN, "%-3s", status);
+
+	printf(" ]");
+}
+
+static void status_print(const char *name, const char *macro,
+			 const char *status)
+{
+	printf("%22s: ", name);
+	on_off_print(status);
+	printf("  # %s\n", macro);
+}
+
+#define STATUS(feature)                                   \
+do {                                                      \
+	if (feature.is_builtin)                               \
+		status_print(feature.name, feature.macro, "on");  \
+	else                                                  \
+		status_print(feature.name, feature.macro, "OFF"); \
+} while (0)
+
+/**
+ * check whether "feature" is built-in with perf
+ * returns:
+ *   -1: Feature not known
+ *    0: Built-in
+ *    1: NOT Built in
+ */
+static int has_support(const char *feature)
+{
+	int res = -1;
+
+	for (int i = 0; supported_features[i].name; ++i) {
+		if (strcmp(feature, supported_features[i].name) == 0) {
+			res = supported_features[i].is_builtin;
+			STATUS(supported_features[i]);
+			break;
+		}
+	}
+
+	if (res == -1) {
+		color_fprintf(stdout, PERF_COLOR_RED, "Feature not known: %s", feature);
+		return -2;
+	}
+
+	return !res;
+}
+
+int cmd_build(int argc, const char **argv)
+{
+	argc = parse_options(argc, argv, build_options, build_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	printf("perf build %s\n", perf_version_string);
+
+	if (build.has)
+		return has_support(build.has);
+
+	return 0;
+}
diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
index f2ab5bae2150..f5b2b5d809ce 100644
--- a/tools/perf/builtin.h
+++ b/tools/perf/builtin.h
@@ -2,11 +2,58 @@
 #ifndef BUILTIN_H
 #define BUILTIN_H
 
+#include <stddef.h>
+#include <linux/compiler.h>
+#include <tools/config.h>
+
+struct feature_support {
+	const char *name;
+	const char *macro;
+	int is_builtin;
+};
+
+#define FEATURE_SUPPORT(name_, macro_) { \
+	.name = name_,                       \
+	.macro = #macro_,                    \
+	.is_builtin = IS_BUILTIN(macro_) }
+
+static struct feature_support supported_features[] __maybe_unused = {
+	FEATURE_SUPPORT("dwarf", HAVE_DWARF_SUPPORT),
+	FEATURE_SUPPORT("dwarf_getlocations", HAVE_DWARF_GETLOCATIONS_SUPPORT),
+#ifndef HAVE_SYSCALL_TABLE_SUPPORT
+	FEATURE_SUPPORT("libaudit", HAVE_LIBAUDIT_SUPPORT),
+#endif
+	FEATURE_SUPPORT("syscall_table", HAVE_SYSCALL_TABLE_SUPPORT),
+	FEATURE_SUPPORT("libbfd", HAVE_LIBBFD_SUPPORT),
+	FEATURE_SUPPORT("debuginfod", HAVE_DEBUGINFOD_SUPPORT),
+	FEATURE_SUPPORT("libelf", HAVE_LIBELF_SUPPORT),
+	FEATURE_SUPPORT("libnuma", HAVE_LIBNUMA_SUPPORT),
+	FEATURE_SUPPORT("numa_num_possible_cpus", HAVE_LIBNUMA_SUPPORT),
+	FEATURE_SUPPORT("libperl", HAVE_LIBPERL_SUPPORT),
+	FEATURE_SUPPORT("libpython", HAVE_LIBPYTHON_SUPPORT),
+	FEATURE_SUPPORT("libslang", HAVE_SLANG_SUPPORT),
+	FEATURE_SUPPORT("libcrypto", HAVE_LIBCRYPTO_SUPPORT),
+	FEATURE_SUPPORT("libunwind", HAVE_LIBUNWIND_SUPPORT),
+	FEATURE_SUPPORT("libdw-dwarf-unwind", HAVE_DWARF_SUPPORT),
+	FEATURE_SUPPORT("zlib", HAVE_ZLIB_SUPPORT),
+	FEATURE_SUPPORT("lzma", HAVE_LZMA_SUPPORT),
+	FEATURE_SUPPORT("get_cpuid", HAVE_AUXTRACE_SUPPORT),
+	FEATURE_SUPPORT("bpf", HAVE_LIBBPF_SUPPORT),
+	FEATURE_SUPPORT("aio", HAVE_AIO_SUPPORT),
+	FEATURE_SUPPORT("zstd", HAVE_ZSTD_SUPPORT),
+	FEATURE_SUPPORT("libpfm4", HAVE_LIBPFM),
+	FEATURE_SUPPORT("libtraceevent", HAVE_LIBTRACEEVENT),
+
+	// this should remain at end, to know the array end
+	FEATURE_SUPPORT(NULL, _)
+};
+
 void list_common_cmds_help(void);
 const char *help_unknown_cmd(const char *cmd);
 
 int cmd_annotate(int argc, const char **argv);
 int cmd_bench(int argc, const char **argv);
+int cmd_build(int argc, const char **argv);
 int cmd_buildid_cache(int argc, const char **argv);
 int cmd_buildid_list(int argc, const char **argv);
 int cmd_config(int argc, const char **argv);
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index d3fc8090413c..95a4a91b1144 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -48,6 +48,7 @@ struct cmd_struct {
 
 static struct cmd_struct commands[] = {
 	{ "archive",	NULL,	0 },
+	{ "build", cmd_build, 0 },
 	{ "buildid-cache", cmd_buildid_cache, 0 },
 	{ "buildid-list", cmd_buildid_list, 0 },
 	{ "config",	cmd_config,	0 },
-- 
2.41.0