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Ignore non-interesting bases when emitting construction vtables. 

llvm-svn: 98177
This commit is contained in:
Anders Carlsson 2010-03-10 19:15:26 +00:00
parent 1794ec4a30
commit 703a08605f
2 changed files with 71 additions and 0 deletions
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11
clang/lib/CodeGen/CGVtable.cpp
View File

@ -1800,6 +1800,17 @@ void VtableBuilder::LayoutSecondaryVtables(BaseSubobject Base,
if (!BaseDecl->isDynamicClass())
continue;
if (isBuildingConstructorVtable()) {
// Itanium C++ ABI 2.6.4:
// Some of the base class subobjects may not need construction virtual
// tables, which will therefore not be present in the construction
// virtual table group, even though the subobject virtual tables are
// present in the main virtual table group for the complete object.
if (!BaseDecl->getNumVBases()) {
continue;
}
}
// Get the base offset of this base.
uint64_t RelativeBaseOffset = Layout.getBaseClassOffset(BaseDecl);
uint64_t BaseOffset = Base.getBaseOffset() + RelativeBaseOffset;

60
clang/test/CodeGenCXX/vtable-layout.cpp
View File

@ -1091,3 +1091,63 @@ class D : virtual B, virtual C {
void D::d() { }
}
namespace Test27 {
// Test that we don't generate a secondary vtable for C in the D-in-E vtable, since
// C doesn't have any virtual bases.
struct A {
virtual void a();
};
struct B {
virtual void b();
};
struct C {
virtual void c();
};
struct D : A, virtual B, C {
virtual void d();
};
// CHECK: Vtable for 'Test27::E' (13 entries).
// CHECK-NEXT: 0 | vbase_offset (16)
// CHECK-NEXT: 1 | offset_to_top (0)
// CHECK-NEXT: 2 | Test27::E RTTI
// CHECK-NEXT: -- (Test27::A, 0) vtable address --
// CHECK-NEXT: -- (Test27::D, 0) vtable address --
// CHECK-NEXT: -- (Test27::E, 0) vtable address --
// CHECK-NEXT: 3 | void Test27::A::a()
// CHECK-NEXT: 4 | void Test27::D::d()
// CHECK-NEXT: 5 | void Test27::E::e()
// CHECK-NEXT: 6 | offset_to_top (-8)
// CHECK-NEXT: 7 | Test27::E RTTI
// CHECK-NEXT: -- (Test27::C, 8) vtable address --
// CHECK-NEXT: 8 | void Test27::C::c()
// CHECK-NEXT: 9 | vcall_offset (0)
// CHECK-NEXT: 10 | offset_to_top (-16)
// CHECK-NEXT: 11 | Test27::E RTTI
// CHECK-NEXT: -- (Test27::B, 16) vtable address --
// CHECK-NEXT: 12 | void Test27::B::b()
// CHECK: Construction vtable for ('Test27::D', 0) in 'Test27::E' (9 entries).
// CHECK-NEXT: 0 | vbase_offset (16)
// CHECK-NEXT: 1 | offset_to_top (0)
// CHECK-NEXT: 2 | Test27::D RTTI
// CHECK-NEXT: -- (Test27::A, 0) vtable address --
// CHECK-NEXT: -- (Test27::D, 0) vtable address --
// CHECK-NEXT: 3 | void Test27::A::a()
// CHECK-NEXT: 4 | void Test27::D::d()
// CHECK-NEXT: 5 | vcall_offset (0)
// CHECK-NEXT: 6 | offset_to_top (-16)
// CHECK-NEXT: 7 | Test27::D RTTI
// CHECK-NEXT: -- (Test27::B, 16) vtable address --
// CHECK-NEXT: 8 | void Test27::B::b()
struct E : D {
virtual void e();
};
void E::e() { }
}