[libcxxabi] Fix multi-level pointer conversions and pointer to member conversion detection.

Summary:
Currently there are bugs in out detection of multi-level pointer conversions and pointer to member conversions. This patch fixes the following issues.

* Allow multi-level pointers with different nested qualifiers.
* Allow multi-level mixed pointers to objects and pointers to members with different nested qualifiers.
* Allow conversions from `int Base::*` to `int Derived::*` but only for non-nested pointers.

There is still some work that needs to be done to clean this patch up but I want to get some input on it.
Open questions:

* Does `__pointer_to_member_type_info::can_catch(...)` need to adjust the pointer if a base to derived conversion is performed?


Reviewers: danalbert, compnerd, mclow.lists

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D8758

llvm-svn: 233984

1 files changed, 145 insertions, 0 deletions

diff --git a/libcxxabi/test/catch_multi_level_pointer.pass.cpp b/libcxxabi/test/catch_multi_level_pointer.pass.cpp
new file mode 100644
index 00000000000..d722ea07b7a
--- /dev/null
+++ b/libcxxabi/test/catch_multi_level_pointer.pass.cpp
@@ -0,0 +1,145 @@
+//===--------------------- catch_pointer_nullptr.cpp ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include <cassert>
+#include <cstdlib>
+#include <iostream>
+
+// Roll our own assertion macro to get better error messages out of the tests.
+// In particular on systems that don't use __PRETTY_FUNCTION__ in assertions.
+#define my_assert(pred, msg) do_assert(pred, msg, __LINE__, __PRETTY_FUNCTION__)
+
+void do_assert(bool assert_passed, const char* msg, int line, const char* func) {
+  if (assert_passed) return;
+  std::cerr << __FILE__ << ":" << line << " " << func
+            << ": Assertion Failed `" << msg << "'\n\n";
+  std::abort();
+}
+
+struct A {};
+struct Base {};
+struct Derived : public Base {};
+
+template <class To>
+bool test_conversion(To) { return true; }
+
+template <class To>
+bool test_conversion(...) { return false; }
+
+template <class Pointer>
+struct CreatePointer {
+  Pointer operator()() const {
+      return (Pointer)0;
+  }
+};
+
+template <class Tp>
+struct CreatePointer<Tp*> {
+  Tp* operator()() const {
+      return (Tp*)42;
+  }
+};
+
+template <class Throw, class Catch>
+void catch_pointer_test() {
+  Throw throw_ptr = CreatePointer<Throw>()();
+  // Use the compiler to determine if the exception of type Throw can be
+  // implicitly converted to type Catch.
+  const bool can_convert = test_conversion<Catch>(throw_ptr);
+  try {
+    throw throw_ptr;
+    assert(false);
+  } catch (Catch catch_ptr) {
+    Catch catch2 = CreatePointer<Catch>()();
+    my_assert(can_convert, "non-convertible type incorrectly caught");
+    my_assert(catch_ptr == catch2,
+              "Thrown pointer does not match caught ptr");
+  } catch (...) {
+    my_assert(!can_convert, "convertible type incorrectly not caught");
+  }
+}
+
+// Generate CV qualified pointer typedefs.
+template <class Tp, bool First = false>
+struct TestTypes {
+  typedef Tp* Type;
+  typedef Tp const* CType;
+  typedef Tp volatile* VType;
+  typedef Tp const volatile* CVType;
+};
+
+// Special case for cv-qualifying a pointer-to-member without adding an extra
+// pointer to it.
+template <class Member, class Class>
+struct TestTypes<Member Class::*, true> {
+  typedef Member (Class::*Type);
+  typedef const Member (Class::*CType);
+  typedef volatile Member (Class::*VType);
+  typedef const volatile Member (Class::*CVType);
+};
+
+template <class Throw, class Catch, int level, bool first = false>
+struct generate_tests_imp {
+  typedef TestTypes<Throw, first> ThrowTypes;
+  typedef TestTypes<Catch, first> CatchTypes;
+  void operator()() {
+      typedef typename ThrowTypes::Type Type;
+      typedef typename ThrowTypes::CType CType;
+      typedef typename ThrowTypes::VType VType;
+      typedef typename ThrowTypes::CVType CVType;
+
+      run_catch_tests<Type>();
+      run_catch_tests<CType>();
+      run_catch_tests<VType>();
+      run_catch_tests<CVType>();
+  }
+
+  template <class ThrowTp>
+  void run_catch_tests() {
+      typedef typename CatchTypes::Type Type;
+      typedef typename CatchTypes::CType CType;
+      typedef typename CatchTypes::VType VType;
+      typedef typename CatchTypes::CVType CVType;
+
+      catch_pointer_test<ThrowTp, Type>();
+      catch_pointer_test<ThrowTp, CType>();
+      catch_pointer_test<ThrowTp, VType>();
+      catch_pointer_test<ThrowTp, CVType>();
+
+      generate_tests_imp<ThrowTp, Type, level-1>()();
+      generate_tests_imp<ThrowTp, CType, level-1>()();
+      generate_tests_imp<ThrowTp, VType, level-1>()();
+      generate_tests_imp<ThrowTp, CVType, level-1>()();
+  }
+};
+
+template <class Throw, class Catch, bool first>
+struct generate_tests_imp<Throw, Catch, 0, first> {
+  void operator()() {
+      catch_pointer_test<Throw, Catch>();
+  }
+};
+
+template <class Throw, class Catch, int level>
+struct generate_tests : generate_tests_imp<Throw, Catch, level, true> {};
+
+int main()
+{
+  generate_tests<int, int, 3>()();
+  generate_tests<Base, Derived, 2>()();
+  generate_tests<Derived, Base, 2>()();
+  generate_tests<int, void, 2>()();
+  generate_tests<void, int, 2>()();
+
+  generate_tests<int A::*, int A::*, 3>()();
+  generate_tests<int A::*, void, 2>()();
+  generate_tests<void, int A::*, 2>()();
+  generate_tests<int Base::*, int Derived::*, 2>()();
+  generate_tests<int Derived::*, int Base::*, 2>()();
+}