Assume foo_array is a pointer to a C structure. GDB must evaluate the
following expression properly, but it does not currently:
(gdb) print 1 && &foo_array[1].a
Attempt to take address of value not located in memory.
The problem is that in EVAL_AVOID_SIDE_EFFECTS mode,
eval.c:evaluate_subexp_standard always returns a not_lval value as the
result for a STRUCTOP_STRUCT operation. As a consequence, the rest of
the code believes that one cannot take the address of the returned
value.
This patch fixes STRUCTOP_STRUCT handling so that the VALUE_LVAL
attribute for the returned value is properly initialized. After this
change, the above session becomes:
(gdb) print 1 && &foo_array[1].a
$1 = 1
gdb/ChangeLog:
* eval.c (evaluate_subexp_standard) <STRUCTOP_STRUCT>: If
EVAL_AVOID_SIDE_EFFECTS mode, forward the VALUE_LVAL attribute
to the returned value.
gdb/testsuite/ChangeLog:
* gdb.base/nested-addr.c: New file.
* gdb.base/nested-addr.exp: New testcase.
Tested on x86_64-linux, no regression.
