From: Anders Carlsson <andersca@mac.com>
Date: Sat, 27 Feb 2010 04:12:52 +0000 (+0000)
Subject: Handle vcall offset sharing between destructors.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5560969d73e3e72747972d0f0f37ca4e3b042186;p=clang

Handle vcall offset sharing between destructors.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97304 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGVtable.cpp b/lib/CodeGen/CGVtable.cpp
index 3c8ddfaed5..89676d4343 100644
--- a/lib/CodeGen/CGVtable.cpp
+++ b/lib/CodeGen/CGVtable.cpp
@@ -835,16 +835,20 @@ bool VCallOffsetMap::MethodsCanShareVCallOffset(const CXXMethodDecl *LHS,
   assert(LHS->isVirtual() && "LHS must be virtual!");
   assert(RHS->isVirtual() && "LHS must be virtual!");
   
+  // A destructor can share a vcall offset with another destructor.
+  if (isa<CXXDestructorDecl>(LHS))
+    return isa<CXXDestructorDecl>(RHS);
+
   // FIXME: We need to check more things here.
   
-  // Must have the same name.
-  // FIXME: are destructors an exception to this?
+  // The methods must have the same name.
   DeclarationName LHSName = LHS->getDeclName();
   DeclarationName RHSName = RHS->getDeclName();
   if (LHSName != RHSName)
     return false;
 
-  return (HasSameVirtualSignature(LHS, RHS));
+  // And the same signatures.
+  return HasSameVirtualSignature(LHS, RHS);
 }
 
 bool VCallOffsetMap::AddVCallOffset(const CXXMethodDecl *MD, 
diff --git a/test/CodeGenCXX/vtable-layout.cpp b/test/CodeGenCXX/vtable-layout.cpp
index abf9d13097..e3a0e8aaac 100644
--- a/test/CodeGenCXX/vtable-layout.cpp
+++ b/test/CodeGenCXX/vtable-layout.cpp
@@ -569,3 +569,43 @@ struct D : A, virtual B, virtual C {
 void D::f() { } 
 
 }
+
+namespace Test16 {
+
+// Test that destructors share vcall offsets.
+
+struct A { virtual ~A(); };
+struct B { virtual ~B(); };
+
+struct C : A, B { virtual ~C(); };
+
+// CHECK:      Vtable for 'Test16::D' (15 entries).
+// CHECK-NEXT:    0 | vbase_offset (8)
+// CHECK-NEXT:    1 | offset_to_top (0)
+// CHECK-NEXT:    2 | Test16::D RTTI
+// CHECK-NEXT:        -- (Test16::D, 0) vtable address --
+// CHECK-NEXT:    3 | void Test16::D::f()
+// CHECK-NEXT:    4 | Test16::D::~D() [complete]
+// CHECK-NEXT:    5 | Test16::D::~D() [deleting]
+// CHECK-NEXT:    6 | vcall_offset (-8)
+// CHECK-NEXT:    7 | offset_to_top (-8)
+// CHECK-NEXT:    8 | Test16::D RTTI
+// CHECK-NEXT:        -- (Test16::A, 8) vtable address --
+// CHECK-NEXT:        -- (Test16::C, 8) vtable address --
+// CHECK-NEXT:    9 | Test16::D::~D() [complete]
+// CHECK-NEXT:        [this adjustment: 0 non-virtual, -24 vcall offset offset]
+// CHECK-NEXT:   10 | Test16::D::~D() [deleting]
+// CHECK-NEXT:        [this adjustment: 0 non-virtual, -24 vcall offset offset]
+// CHECK-NEXT:   11 | offset_to_top (-16)
+// CHECK-NEXT:   12 | Test16::D RTTI
+// CHECK-NEXT:        -- (Test16::B, 16) vtable address --
+// CHECK-NEXT:   13 | Test16::D::~D() [complete]
+// CHECK-NEXT:        [this adjustment: -8 non-virtual, -24 vcall offset offset]
+// CHECK-NEXT:   14 | Test16::D::~D() [deleting]
+// CHECK-NEXT:        [this adjustment: -8 non-virtual, -24 vcall offset offset]
+struct D : virtual C {
+  virtual void f();
+};
+void D::f() { } 
+
+}