clang/test/CodeGenCXX/microsoft-abi-this-nullable.cpp

   1 // RUN: %clang_cc1 -fno-rtti -emit-llvm %s -o - -mconstructor-aliases -triple=i386-pc-win32 | FileCheck %s
   2 // RUN: %clang_cc1 -fno-rtti -emit-llvm %s -o - -mconstructor-aliases -triple=i386-pc-win32 -fno-delete-null-pointer-checks | FileCheck %s
   3
   4 struct Left {
   5   virtual void left();
   6 };
   7
   8 struct Right {
   9   virtual void right();
  10 };
  11
  12 struct ChildNoOverride : Left, Right {
  13 };
  14
  15 struct ChildOverride : Left, Right {
  16   virtual void left();
  17   virtual void right();
  18 };
  19
  20 extern "C" void foo(void *);
  21
  22 void call_left_no_override(ChildNoOverride *child) {
  23   // CHECK: %[[CHILD:.*]] = load ptr
  24   child->left();
  25 }
  26
  27 void ChildOverride::left() {}
  28
  29 void call_right_no_override(ChildNoOverride *child) {
  30   child->right();
  31   // When calling a right base's virtual method, one needs to adjust `this` at the caller site.
  32   //
  33   // CHECK: %[[RIGHT_i8:.*]] = getelementptr inbounds i8, ptr %[[CHILD]], i32 4
  34   //
  35   // CHECK: %[[VFTABLE:.*]] = load ptr, ptr %[[RIGHT_i8]]
  36   // CHECK: %[[VFUN:.*]] = getelementptr inbounds ptr, ptr %[[VFTABLE]], i64 0
  37 }
  38
  39 void ChildOverride::right() {
  40   foo(this);
  41 }
  42
  43 void call_right_override(ChildOverride *child) {
  44   child->right();
  45   // Ensure that `nonnull` and `dereferenceable(N)` are not emitted whether or not null is valid
  46   //
  47   // CHECK: %[[RIGHT:.*]] = getelementptr inbounds i8, ptr %[[CHILD]], i32 4
  48   // CHECK: %[[VFUN_VALUE:.*]] = load ptr, ptr %[[VFUN]]
  49   // CHECK: call x86_thiscallcc void %[[VFUN_VALUE]](ptr noundef %[[RIGHT]])
  50 }