clang/test/CodeGenCXX/RelativeVTablesABI/member-function-pointer.cpp

   1 // Member pointer to virtual function.
   2
   3 // RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -O3 -S -o - -emit-llvm | FileCheck %s
   4
   5 // CHECK:      define{{.*}} void @_Z4funcP1AMS_FvvE(ptr noundef %a, [2 x i64] %fn.coerce) local_unnamed_addr
   6 // CHECK-NEXT: entry:
   7 // CHECK-NEXT:   [[fn_ptr:%.+]] = extractvalue [2 x i64] %fn.coerce, 0
   8 // CHECK-NEXT:   [[adjust:%.+]] = extractvalue [2 x i64] %fn.coerce, 1
   9 // CHECK-NEXT:   [[this_adj:%.+]] = getelementptr inbounds i8, ptr %a, i64 [[adjust]]
  10 // CHECK-NEXT:   [[virtbit:%.+]] = and i64 [[fn_ptr]], 1
  11 // CHECK-NEXT:   [[isvirt:%.+]] = icmp eq i64 [[virtbit]], 0
  12 // CHECK-NEXT:   br i1 [[isvirt]], label %[[nonvirt:.+]], label %[[virt:.+]]
  13 // CHECK:      [[virt]]:
  14
  15 // The loading of the virtual function here should be replaced with a llvm.load.relative() call.
  16 // CHECK-NEXT:   [[vtable:%.+]] = load ptr, ptr [[this_adj]], align 8
  17 // CHECK-NEXT:   [[offset:%.+]] = add nsw i64 [[fn_ptr]], -1
  18 // CHECK-NEXT:   [[ptr:%.+]] = tail call ptr @llvm.load.relative.i64(ptr [[vtable]], i64 [[offset]])
  19 // CHECK-NEXT:   br label %[[memptr_end:.+]]
  20 // CHECK:      [[nonvirt]]:
  21 // CHECK-NEXT:   [[method2:%.+]] = inttoptr i64 [[fn_ptr]] to ptr
  22 // CHECK-NEXT:   br label %[[memptr_end]]
  23 // CHECK:      [[memptr_end]]:
  24 // CHECK-NEXT:   [[method3:%.+]] = phi ptr [ [[ptr]], %[[virt]] ], [ [[method2]], %[[nonvirt]] ]
  25 // CHECK-NEXT:   tail call void [[method3]](ptr {{[^,]*}} [[this_adj]])
  26 // CHECK-NEXT:   ret void
  27 // CHECK-NEXT: }
  28
  29 class A {
  30 public:
  31   virtual void foo();
  32 };
  33
  34 class B : public A {
  35 public:
  36   void foo() override;
  37 };
  38
  39 typedef void (A::*A_foo)();
  40
  41 void func(A *a, A_foo fn) {
  42   (a->*fn)();
  43 }