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Fix ptype bug actually exercised in userdef.exp

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I happened to notice a bug with ptype &Ref, and found out userdef.exp
actually exercises the bug.  With:

class Container
{
public:
  Member m;

  Member& operator* ();
};

Member& Container::operator* ()
{
  return this->m;
}

And 'c' is of type Container:

(gdb) p c
$1 = {m = {z = -9192}}
(gdb) p *c
$2 = (Member &) @0x7fffffffda20: {z = -9192}
(gdb) ptype *c
type = class Member {
  public:
    int z;
} &

(gdb) p &*c
$3 = (Member *) 0x7fffffffda20

(gdb) ptype &*c
type = class Member {
  public:
    int z;
} &*
(gdb)

Notice that last print (&*c) on says the type is a pointer - that's
how you get the address behind a reference.  But notice the last ptype
instead says the type of the same expression is a pointer _reference_.
This looks like a bug to me.

This patch fixes it.  The issue is that we're entering the VALUE_LVAL
(x) == lval_memory branch by mistake for references.  The fix is just
to swap the tests so references are checked first, like value_addr
also handles references first.

Tested on x86_64 Fedora 17.

2013-02-14  Pedro Alves  <palves@redhat.com>

	* eval.c (evaluate_subexp_for_address) <default_case_after_eval,
	EVAL_AVOID_SIDE_EFFECTS>: Swap and handle TYPE_CODE_REF before
	lval_memory.

2013-02-14  Pedro Alves  <palves@redhat.com>

	* gdb.cp/userdef.exp (ptype &*c): Don't expect an &.
This commit is contained in:
Pedro Alves
2013-02-14 12:43:46 +00:00
parent d99b05a32e
commit 4819b3f897
4 changed files with 15 additions and 5 deletions
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8
gdb/eval.c
View File

@@ -2929,12 +2929,12 @@ evaluate_subexp_for_address (struct expression *exp, int *pos,
{
struct type *type = check_typedef (value_type (x));
if (VALUE_LVAL (x) == lval_memory || value_must_coerce_to_target (x))
return value_zero (lookup_pointer_type (value_type (x)),
not_lval);
else if (TYPE_CODE (type) == TYPE_CODE_REF)
if (TYPE_CODE (type) == TYPE_CODE_REF)
return value_zero (lookup_pointer_type (TYPE_TARGET_TYPE (type)),
not_lval);
else if (VALUE_LVAL (x) == lval_memory || value_must_coerce_to_target (x))
return value_zero (lookup_pointer_type (value_type (x)),
not_lval);
else
error (_("Attempt to take address of "
"value not located in memory."));