Can't access anonymous structs in base class through derived class

[cjdb]

Given

struct Base {
  int b;
  struct {
    int x;
  };
};

struct Derived : public Base {
  int d;
};

int main() {
  Derived d;
  d.b = 1;
  d.x = 2;
  d.d = 3;
  return 0;
}

it should be possible to do this in LLDB

(lldb) break 17
(lldb) r
(lldb) script
Python Interactive Interpreter. To exit, type 'quit()', 'exit()' or Ctrl-D.
>>> d = lldb.frame.EvaluateExpression("d")
>>> d.GetChildMemberWithName("b")
(int) b = 1
>>> d.GetChildMemberWithName("x")
(int) x = 2

We end up getting

>>> d.GetChildMemberWithName("x")
No value

After some poking around, we've worked out that LLDB permits accessing base class members from a derived class, anonymous struct members from the enclosing class, but not a base class' anonymous struct members from a derived class. Since C++ permits this, it would be good for LLDB to support it too.

[llvmbot]

@llvm/issue-subscribers-lldb

Author: Christopher Di Bella (cjdb)

Given ```cpp struct Base { int b; struct { int x; }; };

struct Derived : public Base {
int d;
};

int main() {
Derived d;
d.b = 1;
d.x = 2;
d.d = 3;
return 0;
}

it should be possible to do this in LLDB

(lldb) break 17
(lldb) r
(lldb) script
Python Interactive Interpreter. To exit, type 'quit()', 'exit()' or Ctrl-D.
>>> d = lldb.frame.EvaluateExpression("d")
>>> d.GetChildMemberWithName("b")
(int) b = 1
>>> d.GetChildMemberWithName("x")
(int) x = 2

We end up getting

>>> d.GetChildMemberWithName("x")
No value

After some poking around, we've worked out that LLDB permits accessing base class members from a derived class, anonymous struct members from the enclosing class, but not a base class' anonymous struct members from a derived class. Since C++ permits this, it would be good for LLDB to support it too.
</details>

[llvmbot]

@llvm/issue-subscribers-bug

Author: Christopher Di Bella (cjdb)

Given ```cpp struct Base { int b; struct { int x; }; };

struct Derived : public Base {
int d;
};

int main() {
Derived d;
d.b = 1;
d.x = 2;
d.d = 3;
return 0;
}

it should be possible to do this in LLDB

(lldb) break 17
(lldb) r
(lldb) script
Python Interactive Interpreter. To exit, type 'quit()', 'exit()' or Ctrl-D.
>>> d = lldb.frame.EvaluateExpression("d")
>>> d.GetChildMemberWithName("b")
(int) b = 1
>>> d.GetChildMemberWithName("x")
(int) x = 2

We end up getting

>>> d.GetChildMemberWithName("x")
No value

After some poking around, we've worked out that LLDB permits accessing base class members from a derived class, anonymous struct members from the enclosing class, but not a base class' anonymous struct members from a derived class. Since C++ permits this, it would be good for LLDB to support it too.
</details>