0371dff995
When using the relative vtable ABI, if a vtable is not dso_local, it's given private linkage (if not COMDAT) or hidden visibility (if COMDAT) to make it dso_local (to place it in rodata instead of data.rel.ro), and an alias generated with the original linkage and visibility. This alias could later be removed from the symbol table, e.g. if using a version script, at which point we lose all symbol information about the vtable. Use internal linkage instead of private linkage to avoid this. While I'm here, clarify the comment about why COMDAT vtables can't use internal (or private) linkage, and associate it with the else block where hidden visibility is applied instead of internal linkage.
53 lines
4.2 KiB
C++
53 lines
4.2 KiB
C++
// Diamond inheritance.
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// A more complicated multiple inheritance example that includes longer chain of inheritance and a common ancestor.
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// RUN: %clang_cc1 %s -triple=aarch64-unknown-fuchsia -O1 -o - -emit-llvm -fhalf-no-semantic-interposition | FileCheck %s
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// VTable for B should contain offset to top (0), RTTI pointer, A::foo(), and B::barB().
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// CHECK: @_ZTV1B.local = internal unnamed_addr constant { [4 x i32] } { [4 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint (ptr @_ZTI1B.rtti_proxy to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [4 x i32] }, ptr @_ZTV1B.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1A3fooEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [4 x i32] }, ptr @_ZTV1B.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1B4barBEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [4 x i32] }, ptr @_ZTV1B.local, i32 0, i32 0, i32 2) to i64)) to i32)] }, align 4
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// VTable for C should contain offset to top (0), RTTI pointer, A::foo(), and C::barC().
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// CHECK: @_ZTV1C.local = internal unnamed_addr constant { [4 x i32] } { [4 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint (ptr @_ZTI1C.rtti_proxy to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [4 x i32] }, ptr @_ZTV1C.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1A3fooEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [4 x i32] }, ptr @_ZTV1C.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1C4barCEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [4 x i32] }, ptr @_ZTV1C.local, i32 0, i32 0, i32 2) to i64)) to i32)] }, align 4
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// VTable for D should be similar to the mutiple inheritance example where this
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// vtable contains 2 inner vtables:
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// - 1st table containing D::foo(), B::barB(), and D::baz().
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// - 2nd table containing a thunk to D::foo() and C::barC().
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// CHECK: @_ZTV1D.local = internal unnamed_addr constant { [5 x i32], [4 x i32] } { [5 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint (ptr @_ZTI1D.rtti_proxy to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1D3fooEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1B4barBEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1D3bazEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 0, i32 2) to i64)) to i32)], [4 x i32] [i32 -8, i32 trunc (i64 sub (i64 ptrtoint (ptr @_ZTI1D.rtti_proxy to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 1, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZThn8_N1D3fooEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 1, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @_ZN1C4barCEv to i64), i64 ptrtoint (ptr getelementptr inbounds ({ [5 x i32], [4 x i32] }, ptr @_ZTV1D.local, i32 0, i32 1, i32 2) to i64)) to i32)] }, align 4
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// @_ZTV1B ={{.*}} unnamed_addr alias { [4 x i32] }, ptr @_ZTV1B.local
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// @_ZTV1C ={{.*}} unnamed_addr alias { [4 x i32] }, ptr @_ZTV1C.local
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// @_ZTV1D ={{.*}} unnamed_addr alias { [5 x i32], [4 x i32] }, ptr @_ZTV1D.local
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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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virtual void barB();
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};
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class C : public A {
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virtual void barC();
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};
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// Should be a struct with 2 arrays from 2 parents.
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// The 1st contains D::foo(), B::barB(), and D::baz().
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// The 2nd contains C::barC(), and a thunk that points to D::foo().
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class D : public B, C {
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public:
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virtual void baz();
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void foo() override;
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};
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void B::barB() {}
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void C::barC() {}
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void D::foo() {}
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void D::baz() {}
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void D_foo(D *d) {
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d->foo();
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}
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