Split out eval_op_objc_msgcall

This splits OP_OBJC_MSGCALL into a new function for future use.

gdb/ChangeLog
2021-03-08  Tom Tromey  <tom@tromey.com>

	* eval.c (eval_op_objc_msgcall): New function.
	(evaluate_subexp_standard): Use it.
This commit is contained in:
Tom Tromey 2021-03-08 07:27:57 -07:00
parent fb5ba2ab26
commit 5e80600ed0
2 changed files with 286 additions and 249 deletions

View File

@ -1,3 +1,8 @@
2021-03-08 Tom Tromey <tom@tromey.com>
* eval.c (eval_op_objc_msgcall): New function.
(evaluate_subexp_standard): Use it.
2021-03-08 Tom Tromey <tom@tromey.com>
* eval.c (eval_binop_assign_modify): New function.

View File

@ -2089,6 +2089,277 @@ eval_binop_assign_modify (struct type *expect_type, struct expression *exp,
return value_assign (arg1, arg2);
}
/* Note that ARGS needs 2 empty slots up front and must end with a
null pointer. */
static struct value *
eval_op_objc_msgcall (struct type *expect_type, struct expression *exp,
enum noside noside, CORE_ADDR selector,
value *target, gdb::array_view<value *> args)
{
CORE_ADDR responds_selector = 0;
CORE_ADDR method_selector = 0;
int struct_return = 0;
struct value *msg_send = NULL;
struct value *msg_send_stret = NULL;
int gnu_runtime = 0;
struct value *method = NULL;
struct value *called_method = NULL;
struct type *selector_type = NULL;
struct type *long_type;
struct type *type;
struct value *ret = NULL;
CORE_ADDR addr = 0;
value *argvec[5];
long_type = builtin_type (exp->gdbarch)->builtin_long;
selector_type = builtin_type (exp->gdbarch)->builtin_data_ptr;
if (value_as_long (target) == 0)
return value_from_longest (long_type, 0);
if (lookup_minimal_symbol ("objc_msg_lookup", 0, 0).minsym)
gnu_runtime = 1;
/* Find the method dispatch (Apple runtime) or method lookup
(GNU runtime) function for Objective-C. These will be used
to lookup the symbol information for the method. If we
can't find any symbol information, then we'll use these to
call the method, otherwise we can call the method
directly. The msg_send_stret function is used in the special
case of a method that returns a structure (Apple runtime
only). */
if (gnu_runtime)
{
type = selector_type;
type = lookup_function_type (type);
type = lookup_pointer_type (type);
type = lookup_function_type (type);
type = lookup_pointer_type (type);
msg_send = find_function_in_inferior ("objc_msg_lookup", NULL);
msg_send_stret
= find_function_in_inferior ("objc_msg_lookup", NULL);
msg_send = value_from_pointer (type, value_as_address (msg_send));
msg_send_stret = value_from_pointer (type,
value_as_address (msg_send_stret));
}
else
{
msg_send = find_function_in_inferior ("objc_msgSend", NULL);
/* Special dispatcher for methods returning structs. */
msg_send_stret
= find_function_in_inferior ("objc_msgSend_stret", NULL);
}
/* Verify the target object responds to this method. The
standard top-level 'Object' class uses a different name for
the verification method than the non-standard, but more
often used, 'NSObject' class. Make sure we check for both. */
responds_selector
= lookup_child_selector (exp->gdbarch, "respondsToSelector:");
if (responds_selector == 0)
responds_selector
= lookup_child_selector (exp->gdbarch, "respondsTo:");
if (responds_selector == 0)
error (_("no 'respondsTo:' or 'respondsToSelector:' method"));
method_selector
= lookup_child_selector (exp->gdbarch, "methodForSelector:");
if (method_selector == 0)
method_selector
= lookup_child_selector (exp->gdbarch, "methodFor:");
if (method_selector == 0)
error (_("no 'methodFor:' or 'methodForSelector:' method"));
/* Call the verification method, to make sure that the target
class implements the desired method. */
argvec[0] = msg_send;
argvec[1] = target;
argvec[2] = value_from_longest (long_type, responds_selector);
argvec[3] = value_from_longest (long_type, selector);
argvec[4] = 0;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
if (gnu_runtime)
{
/* Function objc_msg_lookup returns a pointer. */
argvec[0] = ret;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
}
if (value_as_long (ret) == 0)
error (_("Target does not respond to this message selector."));
/* Call "methodForSelector:" method, to get the address of a
function method that implements this selector for this
class. If we can find a symbol at that address, then we
know the return type, parameter types etc. (that's a good
thing). */
argvec[0] = msg_send;
argvec[1] = target;
argvec[2] = value_from_longest (long_type, method_selector);
argvec[3] = value_from_longest (long_type, selector);
argvec[4] = 0;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
if (gnu_runtime)
{
argvec[0] = ret;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
}
/* ret should now be the selector. */
addr = value_as_long (ret);
if (addr)
{
struct symbol *sym = NULL;
/* The address might point to a function descriptor;
resolve it to the actual code address instead. */
addr = gdbarch_convert_from_func_ptr_addr (exp->gdbarch, addr,
current_top_target ());
/* Is it a high_level symbol? */
sym = find_pc_function (addr);
if (sym != NULL)
method = value_of_variable (sym, 0);
}
/* If we found a method with symbol information, check to see
if it returns a struct. Otherwise assume it doesn't. */
if (method)
{
CORE_ADDR funaddr;
struct type *val_type;
funaddr = find_function_addr (method, &val_type);
block_for_pc (funaddr);
val_type = check_typedef (val_type);
if ((val_type == NULL)
|| (val_type->code () == TYPE_CODE_ERROR))
{
if (expect_type != NULL)
val_type = expect_type;
}
struct_return = using_struct_return (exp->gdbarch, method,
val_type);
}
else if (expect_type != NULL)
{
struct_return = using_struct_return (exp->gdbarch, NULL,
check_typedef (expect_type));
}
/* Found a function symbol. Now we will substitute its
value in place of the message dispatcher (obj_msgSend),
so that we call the method directly instead of thru
the dispatcher. The main reason for doing this is that
we can now evaluate the return value and parameter values
according to their known data types, in case we need to
do things like promotion, dereferencing, special handling
of structs and doubles, etc.
We want to use the type signature of 'method', but still
jump to objc_msgSend() or objc_msgSend_stret() to better
mimic the behavior of the runtime. */
if (method)
{
if (value_type (method)->code () != TYPE_CODE_FUNC)
error (_("method address has symbol information "
"with non-function type; skipping"));
/* Create a function pointer of the appropriate type, and
replace its value with the value of msg_send or
msg_send_stret. We must use a pointer here, as
msg_send and msg_send_stret are of pointer type, and
the representation may be different on systems that use
function descriptors. */
if (struct_return)
called_method
= value_from_pointer (lookup_pointer_type (value_type (method)),
value_as_address (msg_send_stret));
else
called_method
= value_from_pointer (lookup_pointer_type (value_type (method)),
value_as_address (msg_send));
}
else
{
if (struct_return)
called_method = msg_send_stret;
else
called_method = msg_send;
}
if (noside == EVAL_SKIP)
return eval_skip_value (exp);
if (noside == EVAL_AVOID_SIDE_EFFECTS)
{
/* If the return type doesn't look like a function type,
call an error. This can happen if somebody tries to
turn a variable into a function call. This is here
because people often want to call, eg, strcmp, which
gdb doesn't know is a function. If gdb isn't asked for
it's opinion (ie. through "whatis"), it won't offer
it. */
struct type *callee_type = value_type (called_method);
if (callee_type && callee_type->code () == TYPE_CODE_PTR)
callee_type = TYPE_TARGET_TYPE (callee_type);
callee_type = TYPE_TARGET_TYPE (callee_type);
if (callee_type)
{
if ((callee_type->code () == TYPE_CODE_ERROR) && expect_type)
return allocate_value (expect_type);
else
return allocate_value (callee_type);
}
else
error (_("Expression of type other than "
"\"method returning ...\" used as a method"));
}
/* Now depending on whether we found a symbol for the method,
we will either call the runtime dispatcher or the method
directly. */
args[0] = target;
args[1] = value_from_longest (long_type, selector);
if (gnu_runtime && (method != NULL))
{
/* Function objc_msg_lookup returns a pointer. */
struct type *tem_type = value_type (called_method);
tem_type = lookup_pointer_type (lookup_function_type (tem_type));
deprecated_set_value_type (called_method, tem_type);
called_method = call_function_by_hand (called_method, NULL, args);
}
return call_function_by_hand (called_method, NULL, args);
}
struct value *
evaluate_subexp_standard (struct type *expect_type,
struct expression *exp, int *pos,
@ -2376,36 +2647,20 @@ evaluate_subexp_standard (struct type *expect_type,
case OP_OBJC_MSGCALL:
{ /* Objective C message (method) call. */
CORE_ADDR responds_selector = 0;
CORE_ADDR method_selector = 0;
CORE_ADDR selector = 0;
int struct_return = 0;
enum noside sub_no_side = EVAL_NORMAL;
struct value *msg_send = NULL;
struct value *msg_send_stret = NULL;
int gnu_runtime = 0;
struct value *target = NULL;
struct value *method = NULL;
struct value *called_method = NULL;
struct type *selector_type = NULL;
struct type *long_type;
struct value *ret = NULL;
CORE_ADDR addr = 0;
selector = exp->elts[pc + 1].longconst;
nargs = exp->elts[pc + 2].longconst;
argvec = XALLOCAVEC (struct value *, nargs + 5);
argvec = XALLOCAVEC (struct value *, nargs + 3);
(*pos) += 3;
long_type = builtin_type (exp->gdbarch)->builtin_long;
selector_type = builtin_type (exp->gdbarch)->builtin_data_ptr;
if (noside == EVAL_AVOID_SIDE_EFFECTS)
@ -2416,249 +2671,26 @@ evaluate_subexp_standard (struct type *expect_type,
target = evaluate_subexp (selector_type, exp, pos, sub_no_side);
if (value_as_long (target) == 0)
return value_from_longest (long_type, 0);
if (lookup_minimal_symbol ("objc_msg_lookup", 0, 0).minsym)
gnu_runtime = 1;
/* Find the method dispatch (Apple runtime) or method lookup
(GNU runtime) function for Objective-C. These will be used
to lookup the symbol information for the method. If we
can't find any symbol information, then we'll use these to
call the method, otherwise we can call the method
directly. The msg_send_stret function is used in the special
case of a method that returns a structure (Apple runtime
only). */
if (gnu_runtime)
{
type = selector_type;
type = lookup_function_type (type);
type = lookup_pointer_type (type);
type = lookup_function_type (type);
type = lookup_pointer_type (type);
msg_send = find_function_in_inferior ("objc_msg_lookup", NULL);
msg_send_stret
= find_function_in_inferior ("objc_msg_lookup", NULL);
msg_send = value_from_pointer (type, value_as_address (msg_send));
msg_send_stret = value_from_pointer (type,
value_as_address (msg_send_stret));
}
sub_no_side = EVAL_SKIP;
else
{
msg_send = find_function_in_inferior ("objc_msgSend", NULL);
/* Special dispatcher for methods returning structs. */
msg_send_stret
= find_function_in_inferior ("objc_msgSend_stret", NULL);
}
/* Verify the target object responds to this method. The
standard top-level 'Object' class uses a different name for
the verification method than the non-standard, but more
often used, 'NSObject' class. Make sure we check for both. */
responds_selector
= lookup_child_selector (exp->gdbarch, "respondsToSelector:");
if (responds_selector == 0)
responds_selector
= lookup_child_selector (exp->gdbarch, "respondsTo:");
if (responds_selector == 0)
error (_("no 'respondsTo:' or 'respondsToSelector:' method"));
method_selector
= lookup_child_selector (exp->gdbarch, "methodForSelector:");
if (method_selector == 0)
method_selector
= lookup_child_selector (exp->gdbarch, "methodFor:");
if (method_selector == 0)
error (_("no 'methodFor:' or 'methodForSelector:' method"));
/* Call the verification method, to make sure that the target
class implements the desired method. */
argvec[0] = msg_send;
argvec[1] = target;
argvec[2] = value_from_longest (long_type, responds_selector);
argvec[3] = value_from_longest (long_type, selector);
argvec[4] = 0;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
if (gnu_runtime)
{
/* Function objc_msg_lookup returns a pointer. */
argvec[0] = ret;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
}
if (value_as_long (ret) == 0)
error (_("Target does not respond to this message selector."));
/* Call "methodForSelector:" method, to get the address of a
function method that implements this selector for this
class. If we can find a symbol at that address, then we
know the return type, parameter types etc. (that's a good
thing). */
argvec[0] = msg_send;
argvec[1] = target;
argvec[2] = value_from_longest (long_type, method_selector);
argvec[3] = value_from_longest (long_type, selector);
argvec[4] = 0;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
if (gnu_runtime)
{
argvec[0] = ret;
ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
}
/* ret should now be the selector. */
addr = value_as_long (ret);
if (addr)
{
struct symbol *sym = NULL;
/* The address might point to a function descriptor;
resolve it to the actual code address instead. */
addr = gdbarch_convert_from_func_ptr_addr (exp->gdbarch, addr,
current_top_target ());
/* Is it a high_level symbol? */
sym = find_pc_function (addr);
if (sym != NULL)
method = value_of_variable (sym, 0);
}
/* If we found a method with symbol information, check to see
if it returns a struct. Otherwise assume it doesn't. */
if (method)
{
CORE_ADDR funaddr;
struct type *val_type;
funaddr = find_function_addr (method, &val_type);
block_for_pc (funaddr);
val_type = check_typedef (val_type);
if ((val_type == NULL)
|| (val_type->code () == TYPE_CODE_ERROR))
{
if (expect_type != NULL)
val_type = expect_type;
}
struct_return = using_struct_return (exp->gdbarch, method,
val_type);
}
else if (expect_type != NULL)
{
struct_return = using_struct_return (exp->gdbarch, NULL,
check_typedef (expect_type));
}
/* Found a function symbol. Now we will substitute its
value in place of the message dispatcher (obj_msgSend),
so that we call the method directly instead of thru
the dispatcher. The main reason for doing this is that
we can now evaluate the return value and parameter values
according to their known data types, in case we need to
do things like promotion, dereferencing, special handling
of structs and doubles, etc.
We want to use the type signature of 'method', but still
jump to objc_msgSend() or objc_msgSend_stret() to better
mimic the behavior of the runtime. */
if (method)
{
if (value_type (method)->code () != TYPE_CODE_FUNC)
error (_("method address has symbol information "
"with non-function type; skipping"));
/* Create a function pointer of the appropriate type, and
replace its value with the value of msg_send or
msg_send_stret. We must use a pointer here, as
msg_send and msg_send_stret are of pointer type, and
the representation may be different on systems that use
function descriptors. */
if (struct_return)
called_method
= value_from_pointer (lookup_pointer_type (value_type (method)),
value_as_address (msg_send_stret));
else
called_method
= value_from_pointer (lookup_pointer_type (value_type (method)),
value_as_address (msg_send));
}
else
{
if (struct_return)
called_method = msg_send_stret;
else
called_method = msg_send;
}
if (noside == EVAL_SKIP)
return eval_skip_value (exp);
if (noside == EVAL_AVOID_SIDE_EFFECTS)
{
/* If the return type doesn't look like a function type,
call an error. This can happen if somebody tries to
turn a variable into a function call. This is here
because people often want to call, eg, strcmp, which
gdb doesn't know is a function. If gdb isn't asked for
it's opinion (ie. through "whatis"), it won't offer
it. */
struct type *callee_type = value_type (called_method);
if (callee_type && callee_type->code () == TYPE_CODE_PTR)
callee_type = TYPE_TARGET_TYPE (callee_type);
callee_type = TYPE_TARGET_TYPE (callee_type);
if (callee_type)
{
if ((callee_type->code () == TYPE_CODE_ERROR) && expect_type)
return allocate_value (expect_type);
else
return allocate_value (callee_type);
}
else
error (_("Expression of type other than "
"\"method returning ...\" used as a method"));
}
sub_no_side = noside;
/* Now depending on whether we found a symbol for the method,
we will either call the runtime dispatcher or the method
directly. */
argvec[0] = called_method;
argvec[1] = target;
argvec[2] = value_from_longest (long_type, selector);
argvec[0] = nullptr;
argvec[1] = nullptr;
/* User-supplied arguments. */
for (tem = 0; tem < nargs; tem++)
argvec[tem + 3] = evaluate_subexp_with_coercion (exp, pos, noside);
argvec[tem + 2] = evaluate_subexp_with_coercion (exp, pos,
sub_no_side);
argvec[tem + 3] = 0;
auto call_args = gdb::make_array_view (argvec + 1, nargs + 2);
auto call_args = gdb::make_array_view (argvec, nargs + 3);
if (gnu_runtime && (method != NULL))
{
/* Function objc_msg_lookup returns a pointer. */
deprecated_set_value_type (argvec[0],
lookup_pointer_type (lookup_function_type (value_type (argvec[0]))));
argvec[0] = call_function_by_hand (argvec[0], NULL, call_args);
}
return call_function_by_hand (argvec[0], NULL, call_args);
return eval_op_objc_msgcall (expect_type, exp, noside, selector,
target, call_args);
}
break;