Re: [RFC/RFA] gdb.cp/classes.exp: Don't try to print local variable out of scope

[mec.gnu@mindspring.com (Michael Elizabeth Chastain)]

Hi Corinna,

cv> Basically, the testsuite tries to print the value of a local variable
cv> on a closing brace.  This fails due to the debug info given in this
cv> case:

I have been seeing this also on native i686-pc-linux-gnu.

cv> When the testsuite steps to the closing brace of the function, $pc is
cv> set to the first instruction of the epilogue.  This is exactly the
cv> first instruction which doesn't belong to the lexical block anymore.
cv> Logically, the local variable doesn't exist anymore at this point.

Right.

I want to raise the question: is this really a bug in the gdb test suite,
or is it a bug in gcc?

That is: is a local variable required to exist at the closing brace of a
function?

I think your answer is "no, it's not required to exist, therefore the
gdb test suite should change".  My answer is "reluctantly, no,
it's not required to exist"; I don't think the famous gcc -O0
debug info clause covers this case.  I'm curious what drow and
carlton and other people have to say.

  void foo ()
  {
    int i;
    i = 1;
    bar (i);
  }

  (gdb) break bar
  (gdb) run
  (gdb) finish
  (gdb) print i

Is it okay for gcc to emit debug info that "i" is out of scope here?

cv> I'd suggest to change the testsuite case to add another line to the
cv> function enums1(), so that it's sure to be still in the scope of the
cv> local variable obj_with_enum.

misc.cc is used by three *.exp files so I do not want to touch it
at all, so I am dis-approving your patch.  I will write a patch to
remove the "gdb_test next" in test_enums instead.

Michael C