perf probe: Ignore tail calls to probed functions

[deliverable/linux.git] / tools / perf / util / dwarf-aux.c

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index afa09719336bb9fdeb3babc3a670d8ad9ea12e27..eb47abdcf0acd81fca49155c37e4a7435885e3cc 100644 (file)
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -433,6 +433,43 @@ struct __addr_die_search_param {
        Dwarf_Die       *die_mem;
 };
 
+static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
+{
+       struct __addr_die_search_param *ad = data;
+       Dwarf_Addr addr = 0;
+
+       if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
+           !dwarf_highpc(fn_die, &addr) &&
+           addr == ad->addr) {
+               memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
+               return DWARF_CB_ABORT;
+       }
+       return DWARF_CB_OK;
+}
+
+/**
+ * die_find_tailfunc - Search for a non-inlined function with tail call at
+ * given address
+ * @cu_die: a CU DIE which including @addr
+ * @addr: target address
+ * @die_mem: a buffer for result DIE
+ *
+ * Search for a non-inlined function DIE with tail call at @addr. Stores the
+ * DIE to @die_mem and returns it if found. Returns NULL if failed.
+ */
+Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
+                                   Dwarf_Die *die_mem)
+{
+       struct __addr_die_search_param ad;
+       ad.addr = addr;
+       ad.die_mem = die_mem;
+       /* dwarf_getscopes can't find subprogram. */
+       if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
+               return NULL;
+       else
+               return die_mem;
+}
+
 /* die_find callback for non-inlined function search */
 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
 {