• Masami Hiramatsu's avatar
    perf probe: Avoid searching variables in intermediate scopes · f182e3e1
    Masami Hiramatsu authored
    Fix variable searching logic to search one in inner than local scope or
    global(CU) scope. In the other words, skip searching in intermediate
    scopes.
    
    e.g., in the following code,
    
    int var1;
    
    void inline infunc(int i)
    {
        i++;   <--- [A]
    }
    
    void func(void)
    {
       int var1, var2;
       infunc(var2);
    }
    
    At [A], "var1" should point the global variable "var1", however, if user
    mis-typed as "var2", variable search should be failed. However, current
    logic searches variable infunc() scope, global scope, and then func()
    scope. Thus, it can find "var2" variable in func() scope. This may not
    be what user expects.
    
    So, it would better not search outer scopes except outermost (compile
    unit) scope which contains only global variables, when it failed to find
    given variable in local scope.
    
    E.g.
    
    Without this:
    $ perf probe -V pre_schedule --externs > without.vars
    
    With this:
    $ perf probe -V pre_schedule --externs > with.vars
    
    Check the diff:
    $ diff without.vars with.vars
    88d87
    <               int     cpu
    133d131
    <               long unsigned int*      switch_count
    
    These vars are actually in the scope of schedule(), the caller of
    pre_schedule().
    
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: yrl.pp-manager.tt@hitachi.com
    Link: http://lkml.kernel.org/r/20110811110305.19900.94374.stgit@fedora15Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    f182e3e1
probe-finder.c 38.8 KB