parent-and-child-in-comdats.cpp
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// Cross comdat example
// Both the parent and child VTablea are in their own comdat sections.
// RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -S -o - -emit-llvm -fexperimental-relative-c++-abi-vtables | FileCheck %s
// Comdats are emitted for both A and B in this module and for their respective implementations of foo().
// CHECK: $_ZN1A3fooEv = comdat any
// CHECK: $_ZN1A3fooEv.stub = comdat any
// CHECK: $_ZN1B3fooEv = comdat any
// CHECK: $_ZN1B3fooEv.stub = comdat any
// CHECK: $_ZTV1A = comdat any
// CHECK: $_ZTS1A = comdat any
// CHECK: $_ZTI1A = comdat any
// CHECK: $_ZTI1A.rtti_proxy = comdat any
// CHECK: $_ZTV1B = comdat any
// CHECK: $_ZTS1B = comdat any
// CHECK: $_ZTI1B = comdat any
// CHECK: $_ZTI1B.rtti_proxy = comdat any
// Both the vtables for A and B are emitted and in their own comdats.
// CHECK: @_ZTV1A.local = linkonce_odr hidden unnamed_addr constant { [3 x i32] } { [3 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint ({ i8*, i8* }** @_ZTI1A.rtti_proxy to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [3 x i32] }, { [3 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (void (%class.A*)* @_ZN1A3fooEv.stub to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [3 x i32] }, { [3 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32)] }, comdat($_ZTV1A), align 4
// CHECK: @_ZTV1B.local = linkonce_odr hidden unnamed_addr constant { [3 x i32] } { [3 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint ({ i8*, i8*, i8* }** @_ZTI1B.rtti_proxy to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [3 x i32] }, { [3 x i32] }* @_ZTV1B.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (void (%class.B*)* @_ZN1B3fooEv.stub to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [3 x i32] }, { [3 x i32] }* @_ZTV1B.local, i32 0, i32 0, i32 2) to i64)) to i32)] }, comdat($_ZTV1B), align 4
// CHECK: @_ZTV1A = linkonce_odr unnamed_addr alias { [3 x i32] }, { [3 x i32] }* @_ZTV1A.local
// CHECK: @_ZTV1B = linkonce_odr unnamed_addr alias { [3 x i32] }, { [3 x i32] }* @_ZTV1B.local
// CHECK: declare void @_Z5A_fooP1A(%class.A*)
// The stubs and implementations for foo() are in their own comdat sections.
// CHECK: define linkonce_odr void @_ZN1A3fooEv(%class.A* %this) unnamed_addr #{{[0-9]+}} comdat
// CHECK: define hidden void @_ZN1A3fooEv.stub(%class.A* %0) unnamed_addr #{{[0-9]+}} comdat
// CHECK-NEXT: entry:
// CHECK-NEXT: tail call void @_ZN1A3fooEv(%class.A* %0)
// CHECK-NEXT: ret void
// CHECK-NEXT: }
// CHECK: define linkonce_odr void @_ZN1B3fooEv(%class.B* %this) unnamed_addr #{{[0-9]+}} comdat
// CHECK: define hidden void @_ZN1B3fooEv.stub(%class.B* %0) unnamed_addr #{{[0-9]+}} comdat
// CHECK-NEXT: entry:
// CHECK-NEXT: tail call void @_ZN1B3fooEv(%class.B* %0)
// CHECK-NEXT: ret void
// CHECK-NEXT: }
class A {
public:
inline virtual void foo() {}
};
class B : public A {
public:
inline void foo() override {}
};
void A_foo(A *a);
// func() is used so that the vtable for B is accessed when creating the instance.
void func() {
A a;
B b;
A_foo(&a);
A_foo(&b);
}