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79 lines
3.0 KiB
79 lines
3.0 KiB
4 months ago
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// dynamic_cast
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// Ensure that dynamic casting works normally
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// RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -O3 -S -o - -emit-llvm -fexperimental-relative-c++-abi-vtables | FileCheck %s
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// CHECK: define %class.A* @_Z6upcastP1B(%class.B* readnone %b) local_unnamed_addr
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// CHECK-NEXT: entry:
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// CHECK-NEXT: [[a:%[0-9]+]] = getelementptr %class.B, %class.B* %b, i64 0, i32 0
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// CHECK-NEXT: ret %class.A* [[a]]
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// CHECK-NEXT: }
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// CHECK: define %class.B* @_Z8downcastP1A(%class.A* readonly %a) local_unnamed_addr
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// CHECK-NEXT: entry:
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// CHECK-NEXT: [[isnull:%[0-9]+]] = icmp eq %class.A* %a, null
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// CHECK-NEXT: br i1 [[isnull]], label %[[dynamic_cast_end:[a-z0-9._]+]], label %[[dynamic_cast_notnull:[a-z0-9._]+]]
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// CHECK: [[dynamic_cast_notnull]]:
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// CHECK-NEXT: [[a:%[0-9]+]] = bitcast %class.A* %a to i8*
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// 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)
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// CHECK-NEXT: [[b:%[0-9]+]] = bitcast i8* [[as_b]] to %class.B*
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// CHECK-NEXT: br label %[[dynamic_cast_end]]
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// CHECK: [[dynamic_cast_end]]:
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// CHECK-NEXT: [[res:%[0-9]+]] = phi %class.B* [ [[b]], %[[dynamic_cast_notnull]] ], [ null, %entry ]
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// CHECK-NEXT: ret %class.B* [[res]]
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// CHECK-NEXT: }
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// CHECK: declare i8* @__dynamic_cast(i8*, i8*, i8*, i64) local_unnamed_addr
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// CHECK: define %class.B* @_Z8selfcastP1B(%class.B* readnone returned %b) local_unnamed_addr
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// CHECK-NEXT: entry
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// CHECK-NEXT: ret %class.B* %b
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// CHECK-NEXT: }
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// CHECK: define i8* @_Z9void_castP1B(%class.B* readonly %b) local_unnamed_addr
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// CHECK-NEXT: entry:
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// CHECK-NEXT: [[isnull:%[0-9]+]] = icmp eq %class.B* %b, null
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// CHECK-NEXT: br i1 [[isnull]], label %[[dynamic_cast_end:[a-z0-9._]+]], label %[[dynamic_cast_notnull:[a-z0-9._]+]]
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// CHECK: [[dynamic_cast_notnull]]:
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// CHECK-DAG: [[b2:%[0-9]+]] = bitcast %class.B* %b to i32**
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// CHECK-DAG: [[vtable:%[a-z0-9]+]] = load i32*, i32** [[b2]], align 8
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// CHECK-DAG: [[offset_ptr:%.+]] = getelementptr inbounds i32, i32* [[vtable]], i64 -2
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// CHECK-DAG: [[offset_to_top:%.+]] = load i32, i32* [[offset_ptr]], align 4
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// CHECK-DAG: [[b:%[0-9]+]] = bitcast %class.B* %b to i8*
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// CHECK-DAG: [[offset_to_top2:%.+]] = sext i32 [[offset_to_top]] to i64
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// CHECK-DAG: [[casted:%.+]] = getelementptr inbounds i8, i8* [[b]], i64 [[offset_to_top2]]
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// CHECK-NEXT: br label %[[dynamic_cast_end]]
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// CHECK: [[dynamic_cast_end]]:
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// CHECK-NEXT: [[res:%[0-9]+]] = phi i8* [ [[casted]], %[[dynamic_cast_notnull]] ], [ null, %entry ]
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// CHECK-NEXT: ret i8* [[res]]
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// CHECK-NEXT: }
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class A {
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public:
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virtual void foo();
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};
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class B : public A {
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public:
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void foo() override;
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};
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void A::foo() {}
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void B::foo() {}
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A *upcast(B *b) {
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return dynamic_cast<A *>(b);
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}
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B *downcast(A *a) {
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return dynamic_cast<B *>(a);
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}
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B *selfcast(B *b) {
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return dynamic_cast<B *>(b);
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}
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void *void_cast(B *b) {
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return dynamic_cast<void *>(b);
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}
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