From 703a08605f7f1972d8742c91dba4dbf8c2fb23f9 Mon Sep 17 00:00:00 2001
From: Anders Carlsson <andersca@mac.com>
Date: Wed, 10 Mar 2010 19:15:26 +0000
Subject: [PATCH] Ignore non-interesting bases when emitting construction
vtables.
llvm-svn: 98177
---
clang/lib/CodeGen/CGVtable.cpp | 11 +++++
clang/test/CodeGenCXX/vtable-layout.cpp | 60 +++++++++++++++++++++++++
2 files changed, 71 insertions(+)
diff --git a/clang/lib/CodeGen/CGVtable.cpp b/clang/lib/CodeGen/CGVtable.cpp
index 4500ec033cd8..caf1e1f93e48 100644
--- a/clang/lib/CodeGen/CGVtable.cpp
+++ b/clang/lib/CodeGen/CGVtable.cpp
@@ -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;
diff --git a/clang/test/CodeGenCXX/vtable-layout.cpp b/clang/test/CodeGenCXX/vtable-layout.cpp
index 5c783f1f23dc..19619d0f2b8e 100644
--- a/clang/test/CodeGenCXX/vtable-layout.cpp
+++ b/clang/test/CodeGenCXX/vtable-layout.cpp
@@ -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() { }
+}
--
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