[PATCH v3 26/30 - cleanup] perf clang: Link BPF functions declaration into perf

[Wang Nan <wangnan0@huawei.com>]

Hardcode BPF functions declarations. Following commits will utilizes
clang's virtual file system to automatically include this header to
all BPF scripts.

The generated header is wrapped by a BUILTIN_CLANG_NO_DEFAULT_INCLUDE.
This macro will be used by following commits to allow user disable this
feature.

The C string looks ugly and heavily uses magic numbers because the
header is designed to be included automatically at very first, makes
any dependency or potential conflict harmful. Actually it is
automatically generated using a script:
https://patchwork.kernel.org/patch/9350221
However, that script is fragile so not included by this commit.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/c++/Build                |  1 +
 tools/perf/util/c++/bpf-funcs-str.c      | 49 ++++++++++++++++++++++++++++++++
 tools/perf/util/c++/clang-bpf-includes.h | 12 ++++++++
 3 files changed, 62 insertions(+)
 create mode 100644 tools/perf/util/c++/bpf-funcs-str.c
 create mode 100644 tools/perf/util/c++/clang-bpf-includes.h

diff --git a/tools/perf/util/c++/Build b/tools/perf/util/c++/Build
index 988fef1..bd71abf 100644
--- a/tools/perf/util/c++/Build
+++ b/tools/perf/util/c++/Build
@@ -1,2 +1,3 @@
 libperf-$(CONFIG_CLANGLLVM) += clang.o
 libperf-$(CONFIG_CLANGLLVM) += clang-test.o
+libperf-$(CONFIG_CLANGLLVM) += bpf-funcs-str.o
diff --git a/tools/perf/util/c++/bpf-funcs-str.c b/tools/perf/util/c++/bpf-funcs-str.c
new file mode 100644
index 0000000..ab1a0e3
--- /dev/null
+++ b/tools/perf/util/c++/bpf-funcs-str.c
@@ -0,0 +1,49 @@
+#include "clang-bpf-includes.h"
+const char clang_builtin_bpf_funcs_str[] =
+"#ifdef BUILTIN_CLANG_DEFAULT_INCLUDE\n"
+"#ifndef BPF_FUNCS_DEFINED\n"
+"#define BPF_FUNCS_DEFINED\n"
+"static void *(*bpf_map_lookup_elem)(void *, void *) = (void *)1;\n"
+"static long (*bpf_map_update_elem)(void *, void *, void *, unsigned long) = (void *)2;\n"
+"static long (*bpf_map_delete_elem)(void *, void *) = (void *)3;\n"
+"static long (*bpf_probe_read)(void *, unsigned long, unsigned long) = (void *)4;\n"
+"static long (*bpf_ktime_get_ns)(void) = (void *)5;\n"
+"static long (*bpf_trace_printk)(void *, unsigned long, ...) = (void *)6;\n"
+"static long (*bpf_get_prandom_u32)(void) = (void *)7;\n"
+"static long (*bpf_get_smp_processor_id)(void) = (void *)8;\n"
+"static long (*bpf_skb_store_bytes)(void *, unsigned long, void *, unsigned long, unsigned long) = (void *)9;\n"
+"static long (*bpf_l3_csum_replace)(void *, unsigned long, unsigned long, unsigned long, unsigned long) = (void *)10;\n"
+"static long (*bpf_l4_csum_replace)(void *, unsigned long, unsigned long, unsigned long, unsigned long) = (void *)11;\n"
+"static void (*bpf_tail_call)(void *, void *, unsigned long) = (void *)12;\n"
+"static long (*bpf_clone_redirect)(void *, unsigned long, unsigned long) = (void *)13;\n"
+"static long (*bpf_get_current_pid_tgid)(void) = (void *)14;\n"
+"static long (*bpf_get_current_uid_gid)(void) = (void *)15;\n"
+"static long (*bpf_get_current_comm)(void *, unsigned long) = (void *)16;\n"
+"static long (*bpf_get_cgroup_classid)(void *) = (void *)17;\n"
+"static long (*bpf_skb_vlan_push)(void *, unsigned long, unsigned long) = (void *)18;\n"
+"static long (*bpf_skb_vlan_pop)(void *) = (void *)19;\n"
+"static long (*bpf_skb_get_tunnel_key)(void *, void *, unsigned long, unsigned long) = (void *)20;\n"
+"static long (*bpf_skb_set_tunnel_key)(void *, void *, unsigned long, unsigned long) = (void *)21;\n"
+"static long (*bpf_perf_event_read)(void *, unsigned long) = (void *)22;\n"
+"static long (*bpf_redirect)(unsigned long, unsigned long) = (void *)23;\n"
+"static long (*bpf_get_route_realm)(void *) = (void *)24;\n"
+"static long (*bpf_perf_event_output)(void *, void *, unsigned long, void *, unsigned long) = (void *)25;\n"
+"static long (*bpf_skb_load_bytes)(void *, unsigned long, void *, unsigned long) = (void *)26;\n"
+"static long (*bpf_get_stackid)(void *, void *, unsigned long) = (void *)27;\n"
+"static long (*bpf_csum_diff)(void *, unsigned long, void *, unsigned long, unsigned long) = (void *)28;\n"
+"static long (*bpf_skb_get_tunnel_opt)(void *, void *, unsigned long) = (void *)29;\n"
+"static long (*bpf_skb_set_tunnel_opt)(void *, void *, unsigned long) = (void *)30;\n"
+"static long (*bpf_skb_change_proto)(void *, unsigned long, unsigned long) = (void *)31;\n"
+"static long (*bpf_skb_change_type)(void *, unsigned long) = (void *)32;\n"
+"static long (*bpf_skb_under_cgroup)(void *, void *, unsigned long) = (void *)33;\n"
+"static long (*bpf_get_hash_recalc)(void *) = (void *)34;\n"
+"static long (*bpf_get_current_task)(void) = (void *)35;\n"
+"static long (*bpf_probe_write_user)(unsigned long, void *, unsigned long) = (void *)36;\n"
+"static long (*bpf_current_task_under_cgroup)(void *, unsigned long) = (void *)37;\n"
+"static long (*bpf_skb_change_tail)(void *, unsigned long, unsigned long) = (void *)38;\n"
+"static long (*bpf_skb_pull_data)(void *, unsigned long) = (void *)39;\n"
+"static long (*bpf_csum_update)(void *, unsigned long) = (void *)40;\n"
+"static long (*bpf_set_hash_invalid)(void *) = (void *)41;\n"
+"#endif\n"
+"#endif\n"
+;
diff --git a/tools/perf/util/c++/clang-bpf-includes.h b/tools/perf/util/c++/clang-bpf-includes.h
new file mode 100644
index 0000000..385a5bb
--- /dev/null
+++ b/tools/perf/util/c++/clang-bpf-includes.h
@@ -0,0 +1,12 @@
+#ifndef CLANG_BPF_INCLUDS_H
+#define CLANG_BPF_INCLUDS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern const char clang_builtin_bpf_funcs_str[];
+
+#ifdef __cplusplus
+}
+#endif
+#endif
-- 
2.10.1