Add new bpf_perf_{event|prog}_read_value helpers implementation

docs/kernel-versions.md

@@ -159,3 +159,5 @@ Helper | Kernel version | Commit
 `BPF_FUNC_tail_call()` | 4.2 | [04fd61ab36ec](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=04fd61ab36ec065e194ab5e74ae34a5240d992bb)
 `BPF_FUNC_trace_printk()` | 4.1 | [9c959c863f82](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9c959c863f8217a2ff3d7c296e8223654d240569)
 `BPF_FUNC_xdp_adjust_head()` | 4.10 | [17bedab27231](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=17bedab2723145d17b14084430743549e6943d03)
+`BPF_FUNC_perf_event_read_value()` | 4.15 | [908432ca84fc](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=908432ca84fc229e906ba164219e9ad0fe56f755)
+`BPF_FUNC_perf_prog_read_value()` | 4.15 | [4bebdc7a85aa](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4bebdc7a85aa400c0222b5329861e4ad9252f1e5)

src/cc/export/helpers.h

@@ -96,6 +96,7 @@ struct _name##_table_t { \
   u32 leaf; \
   /* counter = map.perf_read(index) */ \
   u64 (*perf_read) (int); \
+  int (*perf_counter_value) (int, void *, u32); \
   u32 max_entries; \
 }; \
 __attribute__((section("maps/perf_array"))) \
@@ -245,6 +246,10 @@ static int (*bpf_perf_event_output)(void *ctx, void *map, u64 index, void *data,
   (void *) BPF_FUNC_perf_event_output;
 static int (*bpf_skb_load_bytes)(void *ctx, int offset, void *to, u32 len) =
   (void *) BPF_FUNC_skb_load_bytes;
+static int (*bpf_perf_event_read_value)(void *map, u64 flags, void *buf, u32 buf_size) =
+  (void *) BPF_FUNC_perf_event_read_value;
+static int (*bpf_perf_prog_read_value)(void *ctx, void *buf, u32 buf_size) =
+  (void *) BPF_FUNC_perf_prog_read_value;
 
 /* bcc_get_stackid will return a negative value in the case of an error
  *

src/cc/frontends/clang/b_frontend_action.cc

@@ -433,6 +433,9 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
           } else if (memb_name == "perf_read") {
             prefix = "bpf_perf_event_read";
             suffix = ")";
+          } else if (memb_name == "perf_counter_value") {
+            prefix = "bpf_perf_event_read_value";
+            suffix = ")";
           } else {
             error(Call->getLocStart(), "invalid bpf_table operation %0") << memb_name;
             return false;