perf parse-events: Remove BPF event support

New features like the BPF --filter support in perf record have made the
BPF event functionality somewhat redundant. As shown by commit
fcb027c1a4f6 ("perf tools: Revert enable indices setting syntax for BPF
map") and commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix
libbpf 1.0+ compatibility") the BPF event support hasn't been well
maintained and it adds considerable complexity in areas like event
parsing, not least as '/' is a separator for event modifiers as well as
in paths.

This patch removes support in the event parser for BPF events and then
the associated functions are removed. This leads to the removal of whole
source files like bpf-loader.c.  Removing support means that augmented
syscalls in perf trace is broken, this will be fixed in a later commit
adding support using BPF skeletons.

The removal of BPF events causes an unused label warning from flex
generated code, so update build to ignore it:

  ```
  util/parse-events-flex.c:2704:1: error: label ‘find_rule’ defined but not used [-Werror=unused-label]
  2704 | find_rule: /* we branch to this label when backing up */
  ```

Committer notes:

Extracted from a larger patch that was also removing the support for
linking with libllvm and libclang, that were an alternative to using an
external clang execution to compile the .c event source code into BPF
bytecode.

Testing it:

  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Bad event or PMU

  Unabled to find PMU or event on a PMU of 'home'

  Initial error:
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Cannot find PMU `home'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf trace [<options>] [<command>]
      or: perf trace [<options>] -- <command> [<options>]
      or: perf trace record [<options>] [<command>]
      or: perf trace record [<options>] -- <command> [<options>]

      -e, --event <event>   event/syscall selector. use 'perf list' to list available events
  #

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Carsten Haitzler <carsten.haitzler@arm.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Fangrui Song <maskray@google.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: bpf@vger.kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230810184853.2860737-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 0 insertions, 45 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index aec18db7ff23..34bb31f08bb5 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -37,8 +37,6 @@
 #include "util/parse-branch-options.h"
 #include "util/parse-regs-options.h"
 #include "util/perf_api_probe.h"
-#include "util/llvm-utils.h"
-#include "util/bpf-loader.h"
 #include "util/trigger.h"
 #include "util/perf-hooks.h"
 #include "util/cpu-set-sched.h"
@@ -2465,16 +2463,6 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		}
 	}
 
-	err = bpf__apply_obj_config();
-	if (err) {
-		char errbuf[BUFSIZ];
-
-		bpf__strerror_apply_obj_config(err, errbuf, sizeof(errbuf));
-		pr_err("ERROR: Apply config to BPF failed: %s\n",
-			 errbuf);
-		goto out_free_threads;
-	}
-
 	/*
 	 * Normally perf_session__new would do this, but it doesn't have the
 	 * evlist.
@@ -3486,10 +3474,6 @@ static struct option __record_options[] = {
 		    "collect kernel callchains"),
 	OPT_BOOLEAN(0, "user-callchains", &record.opts.user_callchains,
 		    "collect user callchains"),
-	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"),
 	OPT_STRING(0, "vmlinux", &symbol_conf.vmlinux_name,
 		   "file", "vmlinux pathname"),
 	OPT_BOOLEAN(0, "buildid-all", &record.buildid_all,
@@ -3967,27 +3951,6 @@ int cmd_record(int argc, const char **argv)
 
 	setlocale(LC_ALL, "");
 
-#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
-
-#ifndef HAVE_BPF_PROLOGUE
-# if !defined (HAVE_DWARF_SUPPORT)
-#  define REASON  "NO_DWARF=1"
-# elif !defined (HAVE_LIBBPF_SUPPORT)
-#  define REASON  "NO_LIBBPF=1"
-# else
-#  define REASON  "this architecture doesn't support BPF prologue"
-# endif
-# define set_nobuild(s, l, c) set_option_nobuild(record_options, s, l, REASON, c)
-	set_nobuild('\0', "vmlinux", true);
-# undef set_nobuild
-# undef REASON
-#endif
-
 #ifndef HAVE_BPF_SKEL
 # define set_nobuild(s, l, m, c) set_option_nobuild(record_options, s, l, m, c)
 	set_nobuild('\0', "off-cpu", "no BUILD_BPF_SKEL=1", true);
@@ -4116,14 +4079,6 @@ int cmd_record(int argc, const char **argv)
 	if (dry_run)
 		goto out;
 
-	err = bpf__setup_stdout(rec->evlist);
-	if (err) {
-		bpf__strerror_setup_stdout(rec->evlist, err, errbuf, sizeof(errbuf));
-		pr_err("ERROR: Setup BPF stdout failed: %s\n",
-			 errbuf);
-		goto out;
-	}
-
 	err = -ENOMEM;
 
 	if (rec->no_buildid_cache || rec->no_buildid) {