Trying to print this variable with GDB now causes an error, which
is now expected:
(gdb) p some_minsym
'some_minsym' has unknown type; cast it to its declared type
However, trying to cast this symbol, or to take its address
does not work:
(gdb) p integer(some_minsym)
'some_minsym' has unknown type; cast it to its declared type
(gdb) p &some_minsym
'some_minsym' has unknown type; cast it to its declared type
Another manisfestation of this issue can be seen when trying to
insert an Ada exception catchpoint for a specific standard exception
(this only occurs if the Ada runtime is built without debugging
information, which is the default). For instance:
$ (gdb) catch exception constraint_error
warning: failed to reevaluate internal exception condition for catchpoint 0: 'constraint_error' has unknown type; cast it to its declared type
This is because, internally, the cachtpoint uses a condition referencing
a minimal symbol, more precisely:
1. resolve_subexp: Special-case the handling of OP_VAR_MSYM_VALUE
expression elements, where there are no ambiguities to be resolved
in that situation;
2. ada_evaluate_subexp: Enhance the handling of the UNOP_CAST
handling so as to process the case where the target of
the cast is a minimal symbol (as well as a symbol with debugging
information). This mimics what's done in C.
gdb/ChangeLog:
* ada-lang.c (resolve_subexp): Add handling of OP_VAR_MSYM_VALUE.
(ada_evaluate_subexp_for_cast): New function.
(ada_evaluate_subexp) <UNOP_CAST>: Replace code by call to
ada_evaluate_subexp_for_cast.
(ada_evaluate_subexp) <nosideret>: Replace code by call to
eval_skip_value.
* eval.c (evaluate_var_value): Make non-static.
(evaluate_var_msym_value, eval_skip_value): Likewise.
* value.h (evaluate_var_value, evaluate_var_msym_value)
(eval_skip_value): Declare.
gdb/testsuite/ChangeLog:
* gdb.ada/minsyms: New testcase.
Tested on x86_64-linux. No regression. Fixes the following failures:
catch_ex.exp: continuing to Program_Error exception
catch_ex.exp: continuing to failed assertion
catch_ex.exp: continuing to unhandled exception
catch_ex.exp: continuing to program completion
complete.exp: p <Exported_Capitalized>
complete.exp: p Exported_Capitalized
complete.exp: p exported_capitalized
mi_catch_ex.exp: catch Program_Error (unexpected output)
mi_catch_ex.exp: continue to exception catchpoint hit (unknown output after running)
mi_catch_ex.exp: continue to assert failure catchpoint hit (unknown output after running)
mi_catch_ex.exp: continue to unhandled exception catchpoint hit (unknown output after running)
mi_ex_cond.exp: catch C_E if i = 2 (unexpected output)