perf callchain: Add enum match_result for match_chain()

The append_chain() might return either result of match_chain() or other
(error) code.  But match_chain() can return any value in s64 type so
it's hard to check the error case.  Add new enum match_result and make
match_chain() return non-negative values only so that we can check the
error cases.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1455631723-17345-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index a82ea6f..dab2c1f 100644 (file)
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -475,16 +475,32 @@ add_child(struct callchain_node *parent,
        return new;
 }
 
-static s64 match_chain(struct callchain_cursor_node *node,
-                     struct callchain_list *cnode)
+enum match_result {
+       MATCH_ERROR  = -1,
+       MATCH_EQ,
+       MATCH_LT,
+       MATCH_GT,
+};
+
+static enum match_result match_chain(struct callchain_cursor_node *node,
+                                    struct callchain_list *cnode)
 {
        struct symbol *sym = node->sym;
+       u64 left, right;
 
        if (cnode->ms.sym && sym &&
-           callchain_param.key == CCKEY_FUNCTION)
-               return cnode->ms.sym->start - sym->start;
-       else
-               return cnode->ip - node->ip;
+           callchain_param.key == CCKEY_FUNCTION) {
+               left = cnode->ms.sym->start;
+               right = sym->start;
+       } else {
+               left = cnode->ip;
+               right = node->ip;
+       }
+
+       if (left == right)
+               return MATCH_EQ;
+
+       return left > right ? MATCH_GT : MATCH_LT;
 }
 
 /*
@@ -549,7 +565,7 @@ split_add_child(struct callchain_node *parent,
                cnode = list_first_entry(&first->val, struct callchain_list,
                                         list);
 
-               if (match_chain(node, cnode) < 0)
+               if (match_chain(node, cnode) == MATCH_LT)
                        pp = &p->rb_left;
                else
                        pp = &p->rb_right;
@@ -562,7 +578,7 @@ split_add_child(struct callchain_node *parent,
        }
 }
 
-static int
+static enum match_result
 append_chain(struct callchain_node *root,
             struct callchain_cursor *cursor,
             u64 period);
@@ -583,17 +599,17 @@ append_chain_children(struct callchain_node *root,
 
        /* lookup in childrens */
        while (*p) {
-               s64 ret;
+               enum match_result ret;
 
                parent = *p;
                rnode = rb_entry(parent, struct callchain_node, rb_node_in);
 
                /* If at least first entry matches, rely to children */
                ret = append_chain(rnode, cursor, period);
-               if (ret == 0)
+               if (ret == MATCH_EQ)
                        goto inc_children_hit;
 
-               if (ret < 0)
+               if (ret == MATCH_LT)
                        p = &parent->rb_left;
                else
                        p = &parent->rb_right;
@@ -611,7 +627,7 @@ inc_children_hit:
        root->children_count++;
 }
 
-static int
+static enum match_result
 append_chain(struct callchain_node *root,
             struct callchain_cursor *cursor,
             u64 period)
@@ -620,7 +636,7 @@ append_chain(struct callchain_node *root,
        u64 start = cursor->pos;
        bool found = false;
        u64 matches;
-       int cmp = 0;
+       enum match_result cmp = MATCH_ERROR;
 
        /*
         * Lookup in the current node
@@ -636,7 +652,7 @@ append_chain(struct callchain_node *root,
                        break;
 
                cmp = match_chain(node, cnode);
-               if (cmp)
+               if (cmp != MATCH_EQ)
                        break;
 
                found = true;
@@ -646,7 +662,7 @@ append_chain(struct callchain_node *root,
 
        /* matches not, relay no the parent */
        if (!found) {
-               WARN_ONCE(!cmp, "Chain comparison error\n");
+               WARN_ONCE(cmp == MATCH_ERROR, "Chain comparison error\n");
                return cmp;
        }
 
@@ -655,20 +671,20 @@ append_chain(struct callchain_node *root,
        /* we match only a part of the node. Split it and add the new chain */
        if (matches < root->val_nr) {
                split_add_child(root, cursor, cnode, start, matches, period);
-               return 0;
+               return MATCH_EQ;
        }
 
        /* we match 100% of the path, increment the hit */
        if (matches == root->val_nr && cursor->pos == cursor->nr) {
                root->hit += period;
                root->count++;
-               return 0;
+               return MATCH_EQ;
        }
 
        /* We match the node and still have a part remaining */
        append_chain_children(root, cursor, period);
 
-       return 0;
+       return MATCH_EQ;
 }
 
 int callchain_append(struct callchain_root *root,