perf probe: Use libdw callback routines

Use libdw callback functions aggressively, and remove
local tree-search API. This change simplifies the code.

Changes in v3:
 - Cast Dwarf_Addr to uintmax_t for printf-formats.

Changes in v2:
 - Cast Dwarf_Addr to unsigned long long for printf-formats.

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: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133549.6725.81499.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 86 insertions, 177 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c422472fe4d1..6305f344f382 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -38,13 +38,6 @@
 #include "probe-finder.h"
 
 
-/* Dwarf_Die Linkage to parent Die */
-struct die_link {
-        struct die_link *parent;        /* Parent die */
-        Dwarf_Die die;                  /* Current die */
-};
-
-
 /*
  * Generic dwarf analysis helpers
  */
@@ -177,26 +170,6 @@ static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
         return strcmp(tname, name);
 }
 
-/* Check the address is in the subprogram(function). */
-static bool die_within_subprogram(Dwarf_Die *sp_die, Dwarf_Addr addr,
-                                 size_t *offs)
-{
-        Dwarf_Addr epc;
-        int ret;
-
-        ret = dwarf_haspc(sp_die, addr);
-        if (ret <= 0)
-                return false;
-
-        if (offs) {
-                ret = dwarf_entrypc(sp_die, &epc);
-                DIE_IF(ret == -1);
-                *offs = addr - epc;
-        }
-
-        return true;
-}
-
 /* Get entry pc(or low pc, 1st entry of ranges)  of the die */
 static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
 {
@@ -208,70 +181,34 @@ static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
         return epc;
 }
 
-/* Check if the abstract origin's address or not */
-static bool die_compare_abstract_origin(Dwarf_Die *in_die, void *origin_addr)
-{
-        Dwarf_Attribute attr;
-        Dwarf_Die origin;
-
-        if (!dwarf_attr(in_die, DW_AT_abstract_origin, &attr))
-                return false;
-        if (!dwarf_formref_die(&attr, &origin))
-                return false;
-
-        return origin.addr == origin_addr;
-}
-
-/*
- * Search a Die from Die tree.
- * Note: cur_link->die should be deallocated in this function.
- */
-static int __search_die_tree(struct die_link *cur_link,
-                             int (*die_cb)(struct die_link *, void *),
-                             void *data)
+/* Get a variable die */
+static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
+                                    Dwarf_Die *die_mem)
 {
-        struct die_link new_link;
+        Dwarf_Die child_die;
+        int tag;
         int ret;
 
-        if (!die_cb)
-                return 0;
-
-        /* Check current die */
-        while (!(ret = die_cb(cur_link, data))) {
-                /* Check child die */
-                ret = dwarf_child(&cur_link->die, &new_link.die);
-                if (ret == 0) {
-                        new_link.parent = cur_link;
-                        ret = __search_die_tree(&new_link, die_cb, data);
-                        if (ret)
-                                break;
-                }
+        ret = dwarf_child(sp_die, die_mem);
+        if (ret != 0)
+                return NULL;
 
-                /* Move to next sibling */
-                ret = dwarf_siblingof(&cur_link->die, &cur_link->die);
-                if (ret != 0)
-                        return 0;
-        }
-        return ret;
-}
+        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;
 
-/* Search a die in its children's die tree */
-static int search_die_from_children(Dwarf_Die *parent_die,
-                                    int (*die_cb)(struct die_link *, void *),
-                                    void *data)
-{
-        struct die_link new_link;
-        int ret;
+                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);
 
-        new_link.parent = NULL;
-        ret = dwarf_child(parent_die, &new_link.die);
-        if (ret == 0)
-                return __search_die_tree(&new_link, die_cb, data);
-        else
-                return 0;
+        return NULL;
 }
 
-
 /*
  * Probe finder related functions
  */
@@ -347,28 +284,13 @@ error:
             " Perhaps, it has been optimized out.", pf->var);
 }
 
-static int variable_search_cb(struct die_link *dlink, void *data)
-{
-        struct probe_finder *pf = (struct probe_finder *)data;
-        int tag;
-
-        tag = dwarf_tag(&dlink->die);
-        DIE_IF(tag < 0);
-        if ((tag == DW_TAG_formal_parameter ||
-             tag == DW_TAG_variable) &&
-            (die_compare_name(&dlink->die, pf->var) == 0)) {
-                show_variable(&dlink->die, pf);
-                return 1;
-        }
-        /* TODO: Support struct members and arrays */
-        return 0;
-}
-
 /* Find a variable in a subprogram die */
 static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 {
         int ret;
+        Dwarf_Die vr_die;
 
+        /* TODO: Support struct members and arrays */
         if (!is_c_varname(pf->var)) {
                 /* Output raw parameters */
                 ret = snprintf(pf->buf, pf->len, " %s", pf->var);
@@ -379,31 +301,42 @@ static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 
         pr_debug("Searching '%s' variable in context.\n", pf->var);
         /* Search child die for local variables and parameters. */
-        ret = search_die_from_children(sp_die, variable_search_cb, pf);
-        if (!ret)
+        if (!die_find_variable(sp_die, pf->var, &vr_die))
                 die("Failed to find '%s' in this function.", pf->var);
+
+        show_variable(&vr_die, pf);
 }
 
 /* Show a probe point to output buffer */
-static void show_probe_point(Dwarf_Die *sp_die, size_t offs,
+static void show_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)