perf probe: Introduce die_find_child() function

Introduce die_find_child() function to integrate DIE-tree
searching functions.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220558.32050.7905.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 80 insertions, 56 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c91a9605c162..3942e14e95cf 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -186,6 +186,62 @@ static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
         return src;
 }
 
+/* Compare diename and tname */
+static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
+{
+        const char *name;
+        name = dwarf_diename(dw_die);
+        DIE_IF(name == NULL);
+        return strcmp(tname, name);
+}
+
+/* Get entry pc(or low pc, 1st entry of ranges)  of the die */
+static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
+{
+        Dwarf_Addr epc;
+        int ret;
+
+        ret = dwarf_entrypc(dw_die, &epc);
+        DIE_IF(ret == -1);
+        return epc;
+}
+
+/* Return values for die_find callbacks */
+enum {
+        DIE_FIND_CB_FOUND = 0,          /* End of Search */
+        DIE_FIND_CB_CHILD = 1,          /* Search only children */
+        DIE_FIND_CB_SIBLING = 2,        /* Search only siblings */
+        DIE_FIND_CB_CONTINUE = 3,       /* Search children and siblings */
+};
+
+/* Search a child die */
+static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
+                                 int (*callback)(Dwarf_Die *, void *),
+                                 void *data, Dwarf_Die *die_mem)
+{
+        Dwarf_Die child_die;
+        int ret;
+
+        ret = dwarf_child(rt_die, die_mem);
+        if (ret != 0)
+                return NULL;
+
+        do {
+                ret = callback(die_mem, data);
+                if (ret == DIE_FIND_CB_FOUND)
+                        return die_mem;
+
+                if ((ret & DIE_FIND_CB_CHILD) &&
+                    die_find_child(die_mem, callback, data, &child_die)) {
+                        memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
+                        return die_mem;
+                }
+        } while ((ret & DIE_FIND_CB_SIBLING) &&
+                 dwarf_siblingof(die_mem, die_mem) == 0);
+
+        return NULL;
+}
+
 struct __addr_die_search_param {
         Dwarf_Addr      addr;
         Dwarf_Die       *die_mem;
@@ -217,77 +273,45 @@ static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
                 return die_mem;
 }
 
-/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
-static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
-                                      Dwarf_Die *die_mem)
+/* die_find callback for inline function search */
+static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
 {
-        Dwarf_Die child_die;
-        int ret;
+        Dwarf_Addr *addr = data;
 
-        ret = dwarf_child(sp_die, die_mem);
-        if (ret != 0)
-                return NULL;
-
-        do {
-                if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
-                    dwarf_haspc(die_mem, addr))
-                        return die_mem;
+        if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
+            dwarf_haspc(die_mem, *addr))
+                return DIE_FIND_CB_FOUND;
 
-                if (die_find_inlinefunc(die_mem, addr, &child_die)) {
-                        memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
-                        return die_mem;
-                }
-        } while (dwarf_siblingof(die_mem, die_mem) == 0);
-
-        return NULL;
+        return DIE_FIND_CB_CONTINUE;
 }
 
-/* Compare diename and tname */
-static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
+/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
+static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
+                                      Dwarf_Die *die_mem)
 {
-        const char *name;
-        name = dwarf_diename(dw_die);
-        DIE_IF(name == NULL);
-        return strcmp(tname, name);
+        return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 }
 
-/* Get entry pc(or low pc, 1st entry of ranges)  of the die */
-static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
+static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 {
-        Dwarf_Addr epc;
-        int ret;
+        const char *name = data;
+        int tag;
 
-        ret = dwarf_entrypc(dw_die, &epc);
-        DIE_IF(ret == -1);
-        return epc;
+        tag = dwarf_tag(die_mem);
+        if ((tag == DW_TAG_formal_parameter ||
+             tag == DW_TAG_variable) &&
+            (die_compare_name(die_mem, name) == 0))
+                return DIE_FIND_CB_FOUND;
+
+        return DIE_FIND_CB_CONTINUE;
 }
 
-/* Get a variable die */
+/* Find a variable called 'name' */
 static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
                                     Dwarf_Die *die_mem)
 {
-        Dwarf_Die child_die;
-        int tag;
-        int ret;
-
-        ret = dwarf_child(sp_die, die_mem);
-        if (ret != 0)
-                return NULL;
-
-        do {
-                tag = dwarf_tag(die_mem);
-                if ((tag == DW_TAG_formal_parameter ||
-                     tag == DW_TAG_variable) &&
-                    (die_compare_name(die_mem, name) == 0))
-                        return die_mem;
-
-                if (die_find_variable(die_mem, name, &child_die)) {
-                        memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
-                        return die_mem;
-                }
-        } while (dwarf_siblingof(die_mem, die_mem) == 0);
-
-        return NULL;
+        return die_find_child(sp_die, __die_find_variable_cb, (void *)name,
+                              die_mem);
 }
 
 /*