Split reinterpret_casts of member pointers out from CK_BitCast; this

is general goodness because representations of member pointers are
not always equivalent across member pointer types on all ABIs
(even though this isn't really standard-endorsed).

Take advantage of the new information to teach IR-generation how
to do these reinterprets in constant initializers.  Make sure this
works when intermingled with hierarchy conversions (although
this is not part of our motivating use case).  Doing this in the
constant-evaluator would probably have been better, but that would
require a *lot* of extra structure in the representation of
constant member pointers:  you'd really have to track an arbitrary
chain of hierarchy conversions and reinterpretations in order to
get this right.  Ultimately, this seems less complex.  I also
wasn't quite sure how to extend the constant evaluator to handle
foldings that we don't actually want to treat as extended
constant expressions.

llvm-svn: 150551

1 files changed, 40 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/member-function-pointers.cpp b/clang/test/CodeGenCXX/member-function-pointers.cpp
index 5ce5fbf..2417aa4 100644
--- a/clang/test/CodeGenCXX/member-function-pointers.cpp
+++ b/clang/test/CodeGenCXX/member-function-pointers.cpp
@@ -28,6 +28,16 @@ void (C::*pc2)() = &C::f;
 // CHECK: @pc3 = global { i64, i64 } { i64 1, i64 0 }, align 8
 void (A::*pc3)() = &A::vf1;
 
+// Tests for test10.
+// CHECK: @_ZN6test101aE = global { i64, i64 } { i64 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i64), i64 0 }, align 8
+// CHECK: @_ZN6test101bE = global { i64, i64 } { i64 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i64), i64 8 }, align 8
+// CHECK: @_ZN6test101cE = global { i64, i64 } { i64 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i64), i64 8 }, align 8
+// CHECK: @_ZN6test101dE = global { i64, i64 } { i64 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i64), i64 16 }, align 8
+// CHECK-LP32: @_ZN6test101aE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 0 }, align 4
+// CHECK-LP32: @_ZN6test101bE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 4 }, align 4
+// CHECK-LP32: @_ZN6test101cE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 4 }, align 4
+// CHECK-LP32: @_ZN6test101dE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 8 }, align 4
+
 void f() {
   // CHECK: store { i64, i64 } zeroinitializer, { i64, i64 }* @pa
   pa = 0;
@@ -232,3 +242,33 @@ namespace test9 {
     static S array[] = { (fooptr) &B::foo };
   }
 }
+
+// rdar://problem/10815683 - Verify that we can emit reinterprets of
+// member pointers as constant initializers.  For added trickiness,
+// we also add some non-trivial adjustments.
+namespace test10 {
+  struct A {
+    int nonEmpty;
+    void foo();
+  };
+  struct B : public A {
+    virtual void requireNonZeroAdjustment();
+  };
+  struct C {
+    int nonEmpty;
+  };
+  struct D : public C {
+    virtual void requireNonZeroAdjustment();
+  };
+
+  // Non-ARM tests at top of file.
+  void (A::*a)() = &A::foo;
+  void (B::*b)() = (void (B::*)()) &A::foo;
+  void (C::*c)() = (void (C::*)()) (void (B::*)()) &A::foo;
+  void (D::*d)() = (void (C::*)()) (void (B::*)()) &A::foo;
+}
+// It's not that the offsets are doubled on ARM, it's that they're left-shifted by 1.
+// CHECK-ARM: @_ZN6test101aE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 0 }, align 4
+// CHECK-ARM: @_ZN6test101bE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 8 }, align 4
+// CHECK-ARM: @_ZN6test101cE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 8 }, align 4
+// CHECK-ARM: @_ZN6test101dE = global { i32, i32 } { i32 ptrtoint (void (%"struct.test10::A"*)* @_ZN6test101A3fooEv to i32), i32 16 }, align 4