perf env: Remove global perf_env

The global perf_env was used for the host, but if a perf_env wasn't
easy to come by it was used in a lot of places where potentially
recorded and host data could be confused. Remove the global variable
as now the majority of accesses retrieve the perf_env for the host
from the session.

Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-20-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Author: captain5050

tools/perf/perf.c

@@ -346,12 +346,9 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 		use_pager = 1;
 	commit_pager_choice();
 
-	perf_env__init(&perf_env);
-	perf_env__set_cmdline(&perf_env, argc, argv);
 	status = p->fn(argc, argv);
 	perf_config__exit();
 	exit_browser(status);
-	perf_env__exit(&perf_env);
 
 	if (status)
 		return status & 0xff;

tools/perf/util/bpf-event.c

@@ -549,7 +549,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 	 * for perf-record and perf-report use header.env;
 	 * otherwise, use global perf_env.
 	 */
-	env = session->data ? perf_session__env(session) : &perf_env;
+	env = perf_session__env(session);
 
 	arrays = 1UL << PERF_BPIL_JITED_KSYMS;
 	arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;

tools/perf/util/env.c

@@ -19,8 +19,6 @@
 #include "strbuf.h"
 #include "trace/beauty/beauty.h"
 
-struct perf_env perf_env;
-
 #ifdef HAVE_LIBBPF_SUPPORT
 #include "bpf-event.h"
 #include "bpf-utils.h"

tools/perf/util/env.h

@@ -150,8 +150,6 @@ enum perf_compress_type {
 struct bpf_prog_info_node;
 struct btf_node;
 
-extern struct perf_env perf_env;
-
 int perf_env__read_core_pmu_caps(struct perf_env *env);
 void perf_env__exit(struct perf_env *env);
 

tools/perf/util/evsel.c

@@ -3882,7 +3882,7 @@ struct perf_env *evsel__env(struct evsel *evsel)
 {
 	struct perf_session *session = evsel__session(evsel);
 
-	return session ? perf_session__env(session) : &perf_env;
+	return session ? perf_session__env(session) : NULL;
 }
 
 static int store_evsel_ids(struct evsel *evsel, struct evlist *evlist)

tools/perf/util/session.c

@@ -192,7 +192,8 @@ struct perf_session *__perf_session__new(struct perf_data *data,
 				symbol_conf.kallsyms_name = perf_data__kallsyms_name(data);
 		}
 	} else  {
-		session->machines.host.env = host_env ?: &perf_env;
+		assert(host_env != NULL);
+		session->machines.host.env = host_env;
 	}
 	if (session->evlist)
 		session->evlist->session = session;