[v3] Allow calling of user-defined function call operators
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| linaro-tcwg-bot/tcwg_gdb_check--master-aarch64 |
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Commit Message
Currently it's not possible to call user-defined function call
operators, at least not without specifying operator() directly:
```
(gdb) l 1
1 struct S {
2 int operator() (int x) { return x + 5; }
3 };
4
5 int main () {
6 S s;
7
8 return s(23);
9 }
(gdb) p s(10)
Invalid data type for function to be called.
(gdb) p s.operator()(10)
$1 = 15
```
This now looks if an user-defined call operator is available when
trying to 'call' a struct value, and calls it instead, making this
possible:
```
(gdb) p s(10)
$1 = 15
```
The change in operation::evaluate_funcall is to make sure the type
fields are only used for function types, only they use them as the
argument types.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=12213
---
v2:
- Move the logic into evaluate_subexp_do_call, to avoid duplication in
every evaluate_funcall of each operation subclass.
This makes it now work for some cases it didn't in v1, like if it's
called on a class member (`print c.m(5)` in the new test).
- Added tests for other (struct member) operations.
v3:
- Additional comments.
---
gdb/eval.c | 32 +++++++++++++++++++++++++++++---
gdb/testsuite/gdb.cp/userdef.cc | 22 ++++++++++++++++++++++
gdb/testsuite/gdb.cp/userdef.exp | 7 +++++++
3 files changed, 58 insertions(+), 3 deletions(-)
Comments
>>>>> "Hannes" == Hannes Domani <ssbssa@yahoo.de> writes:
Hannes> + type *ftype = callee->type ();
Hannes> +
Hannes> + /* If the callee is a struct, there might be a user-defined function call
Hannes> + operator that should be used instead. */
Hannes> + std::vector<value *> vals;
Hannes> + if (overload_resolution
Hannes> + && exp->language_defn->la_language == language_cplus
Hannes> + && check_typedef (ftype)->code () == TYPE_CODE_STRUCT)
[...]
Hannes> + find_overload_match (vals, "operator()", METHOD, &vals[0], nullptr,
Hannes> + &callee, nullptr, &static_memfuncp, 0, noside);
[...]
Hannes> if (ftype->code () == TYPE_CODE_INTERNAL_FUNCTION)
Should ftype be changed to the type of operator() after the call to
find_overload_match? Otherwise it seems like later code could use the
wrong type here?
Tom
@@ -588,14 +588,36 @@ evaluate_subexp_do_call (expression *exp, enum noside noside,
{
if (callee == NULL)
error (_("Cannot evaluate function -- may be inlined"));
+
+ type *ftype = callee->type ();
+
+ /* If the callee is a struct, there might be a user-defined function call
+ operator that should be used instead. */
+ std::vector<value *> vals;
+ if (overload_resolution
+ && exp->language_defn->la_language == language_cplus
+ && check_typedef (ftype)->code () == TYPE_CODE_STRUCT)
+ {
+ /* Include space for the `this' pointer at the start. */
+ vals.resize (argvec.size () + 1);
+
+ vals[0] = value_addr (callee);
+ for (int i = 0; i < argvec.size (); ++i)
+ vals[i + 1] = argvec[i];
+
+ int static_memfuncp;
+ find_overload_match (vals, "operator()", METHOD, &vals[0], nullptr,
+ &callee, nullptr, &static_memfuncp, 0, noside);
+ if (!static_memfuncp)
+ argvec = vals;
+ }
+
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. */
- type *ftype = callee->type ();
-
if (ftype->code () == TYPE_CODE_INTERNAL_FUNCTION)
{
/* We don't know anything about what the internal
@@ -666,9 +688,13 @@ operation::evaluate_funcall (struct type *expect_type,
struct type *type = callee->type ();
if (type->code () == TYPE_CODE_PTR)
type = type->target_type ();
+ /* If type is a struct, num_fields would refer to the number of
+ members in the type, not the number of arguments. */
+ bool type_has_arguments
+ = type->code () == TYPE_CODE_FUNC || type->code () == TYPE_CODE_METHOD;
for (int i = 0; i < args.size (); ++i)
{
- if (i < type->num_fields ())
+ if (type_has_arguments && i < type->num_fields ())
vals[i] = args[i]->evaluate (type->field (i).type (), exp, noside);
else
vals[i] = args[i]->evaluate_with_coercion (exp, noside);
@@ -307,8 +307,21 @@ class Member
{
public:
int z;
+
+ int operator() ();
+ int operator() (int);
};
+int Member::operator() ()
+{
+ return z;
+}
+
+int Member::operator() (int value)
+{
+ return value * z;
+}
+
bool operator== (const Member &m1, const Member &m2)
{
return m1.z == m2.z;
@@ -335,9 +348,11 @@ int main (void)
Container c;
Member mem1, mem2;
int val;
+ Member Container::* mptr = &Container::m;
mem1.z = 5;
mem2.z = 7;
+ c.m.z = 8;
marker1(); // marker1-returns-here
cout << one; // marker1-returns-here
@@ -404,6 +419,13 @@ int main (void)
++three;
cout << "preinc " << three;
+ val = mem1 ();
+ cout << "funcall " << val << endl;
+ val = mem1 (10);
+ cout << "funcall 2 " << val << endl;
+ val = (c.*mptr) (11);
+ cout << "funcall 3 " << val << endl;
+
(*c).z = 1;
return 0;
@@ -132,4 +132,11 @@ gdb_test "ptype &*c" "type = (struct|class) Member {(\[\r\n \]+public:)?\[\r\n \
gdb_test "print operator== (mem1, mem2)" " = false"
gdb_test "print operator== (mem1, mem1)" " = true"
+gdb_test "print mem1()" " = 5"
+gdb_test "print mem1(10)" " = 50"
+gdb_test "print (*&mem1)(2)" " = 10"
+gdb_test "print (c.*mptr)(3)" " = 24"
+gdb_test "print (&c)->m(4)" " = 32"
+gdb_test "print c.m(5)" " = 40"
+
gdb_exit