perf thread-stack: Represent jmps to the start of a different symbol

[linux-2.6-microblaze.git] / tools / perf / util / thread-stack.c

diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
index 7f8eff0..f52c0f9 100644 (file)
--- a/tools/perf/util/thread-stack.c
+++ b/tools/perf/util/thread-stack.c
@@ -38,6 +38,7 @@
  * @cp: call path
  * @no_call: a 'call' was not seen
  * @trace_end: a 'call' but trace ended
+ * @non_call: a branch but not a 'call' to the start of a different symbol
  */
 struct thread_stack_entry {
        u64 ret_addr;
@@ -47,6 +48,7 @@ struct thread_stack_entry {
        struct call_path *cp;
        bool no_call;
        bool trace_end;
+       bool non_call;
 };
 
 /**
@@ -268,6 +270,8 @@ static int thread_stack__call_return(struct thread *thread,
                cr.flags |= CALL_RETURN_NO_CALL;
        if (no_return)
                cr.flags |= CALL_RETURN_NO_RETURN;
+       if (tse->non_call)
+               cr.flags |= CALL_RETURN_NON_CALL;
 
        return crp->process(&cr, crp->data);
 }
@@ -510,6 +514,7 @@ static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr,
        tse->cp = cp;
        tse->no_call = no_call;
        tse->trace_end = trace_end;
+       tse->non_call = false;
 
        return 0;
 }
@@ -531,14 +536,16 @@ static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts,
                                                         timestamp, ref, false);
        }
 
-       if (ts->stack[ts->cnt - 1].ret_addr == ret_addr) {
+       if (ts->stack[ts->cnt - 1].ret_addr == ret_addr &&
+           !ts->stack[ts->cnt - 1].non_call) {
                return thread_stack__call_return(thread, ts, --ts->cnt,
                                                 timestamp, ref, false);
        } else {
                size_t i = ts->cnt - 1;
 
                while (i--) {
-                       if (ts->stack[i].ret_addr != ret_addr)
+                       if (ts->stack[i].ret_addr != ret_addr ||
+                           ts->stack[i].non_call)
                                continue;
                        i += 1;
                        while (ts->cnt > i) {
@@ -757,6 +764,25 @@ int thread_stack__process(struct thread *thread, struct comm *comm,
                err = thread_stack__trace_begin(thread, ts, sample->time, ref);
        } else if (sample->flags & PERF_IP_FLAG_TRACE_END) {
                err = thread_stack__trace_end(ts, sample, ref);
+       } else if (sample->flags & PERF_IP_FLAG_BRANCH &&
+                  from_al->sym != to_al->sym && to_al->sym &&
+                  to_al->addr == to_al->sym->start) {
+               struct call_path_root *cpr = ts->crp->cpr;
+               struct call_path *cp;
+
+               /*
+                * The compiler might optimize a call/ret combination by making
+                * it a jmp. Make that visible by recording on the stack a
+                * branch to the start of a different symbol. Note, that means
+                * when a ret pops the stack, all jmps must be popped off first.
+                */
+               cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,
+                                       to_al->sym, sample->addr,
+                                       ts->kernel_start);
+               err = thread_stack__push_cp(ts, 0, sample->time, ref, cp, false,
+                                           false);
+               if (!err)
+                       ts->stack[ts->cnt - 1].non_call = true;
        }
 
        return err;