1 // dynamic_cast 2 // Ensure that dynamic casting works normally 3 4 // RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -O3 -S -o - -emit-llvm | FileCheck %s 5 6 // CHECK: define{{.*}} %class.A* @_Z6upcastP1B(%class.B* noundef readnone %b) local_unnamed_addr 7 // CHECK-NEXT: entry: 8 // CHECK-NEXT: [[a:%[0-9]+]] = getelementptr %class.B, %class.B* %b, i64 0, i32 0 9 // CHECK-NEXT: ret %class.A* [[a]] 10 // CHECK-NEXT: } 11 12 // CHECK: define{{.*}} %class.B* @_Z8downcastP1A(%class.A* noundef readonly %a) local_unnamed_addr 13 // CHECK-NEXT: entry: 14 // CHECK-NEXT: [[isnull:%[0-9]+]] = icmp eq %class.A* %a, null 15 // CHECK-NEXT: br i1 [[isnull]], label %[[dynamic_cast_end:[a-z0-9._]+]], label %[[dynamic_cast_notnull:[a-z0-9._]+]] 16 // CHECK: [[dynamic_cast_notnull]]: 17 // CHECK-NEXT: [[a:%[0-9]+]] = bitcast %class.A* %a to i8* 18 // CHECK-NEXT: [[as_b:%[0-9]+]] = tail call i8* @__dynamic_cast(i8* nonnull [[a]], i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*), i8* bitcast ({ i8*, i8*, i8* }* @_ZTI1B to i8*), i64 0) 19 // CHECK-NEXT: [[b:%[0-9]+]] = bitcast i8* [[as_b]] to %class.B* 20 // CHECK-NEXT: br label %[[dynamic_cast_end]] 21 // CHECK: [[dynamic_cast_end]]: 22 // CHECK-NEXT: [[res:%[0-9]+]] = phi %class.B* [ [[b]], %[[dynamic_cast_notnull]] ], [ null, %entry ] 23 // CHECK-NEXT: ret %class.B* [[res]] 24 // CHECK-NEXT: } 25 26 // CHECK: declare i8* @__dynamic_cast(i8*, i8*, i8*, i64) local_unnamed_addr 27 28 // CHECK: define{{.*}} %class.B* @_Z8selfcastP1B(%class.B* noundef readnone returned %b) local_unnamed_addr 29 // CHECK-NEXT: entry 30 // CHECK-NEXT: ret %class.B* %b 31 // CHECK-NEXT: } 32 33 // CHECK: define{{.*}} i8* @_Z9void_castP1B(%class.B* noundef readonly %b) local_unnamed_addr 34 // CHECK-NEXT: entry: 35 // CHECK-NEXT: [[isnull:%[0-9]+]] = icmp eq %class.B* %b, null 36 // CHECK-NEXT: br i1 [[isnull]], label %[[dynamic_cast_end:[a-z0-9._]+]], label %[[dynamic_cast_notnull:[a-z0-9._]+]] 37 // CHECK: [[dynamic_cast_notnull]]: 38 // CHECK-DAG: [[b2:%[0-9]+]] = bitcast %class.B* %b to i32** 39 // CHECK-DAG: [[vtable:%[a-z0-9]+]] = load i32*, i32** [[b2]], align 8 40 // CHECK-DAG: [[offset_ptr:%.+]] = getelementptr inbounds i32, i32* [[vtable]], i64 -2 41 // CHECK-DAG: [[offset_to_top:%.+]] = load i32, i32* [[offset_ptr]], align 4 42 // CHECK-DAG: [[b:%[0-9]+]] = bitcast %class.B* %b to i8* 43 // CHECK-DAG: [[offset_to_top2:%.+]] = sext i32 [[offset_to_top]] to i64 44 // CHECK-DAG: [[casted:%.+]] = getelementptr inbounds i8, i8* [[b]], i64 [[offset_to_top2]] 45 // CHECK-NEXT: br label %[[dynamic_cast_end]] 46 // CHECK: [[dynamic_cast_end]]: 47 // CHECK-NEXT: [[res:%[0-9]+]] = phi i8* [ [[casted]], %[[dynamic_cast_notnull]] ], [ null, %entry ] 48 // CHECK-NEXT: ret i8* [[res]] 49 // CHECK-NEXT: } 50 51 class A { 52 public: 53 virtual void foo(); 54 }; 55 56 class B : public A { 57 public: 58 void foo() override; 59 }; 60 61 void A::foo() {} 62 void B::foo() {} 63 64 A *upcast(B *b) { 65 return dynamic_cast<A *>(b); 66 } 67 68 B *downcast(A *a) { 69 return dynamic_cast<B *>(a); 70 } 71 72 B *selfcast(B *b) { 73 return dynamic_cast<B *>(b); 74 } 75 76 void *void_cast(B *b) { 77 return dynamic_cast<void *>(b); 78 } 79