Currently we're initializing the vtable pointers of a class only after
the bases are completely initialized. This won't work --- base
initializer expressions can rely on the vtables having been set up.
Check for uses of 'this' in the initializers and force a vtable
initialization if found.
This might not be good enough; we might need to extend this to handle
the possibility of arbitrary code finding an external reference to this
(not yet completely-constructed!) object and accessing through it,
in which case we'll probably find ourselves doing a lot more unnecessary
stores.
llvm-svn: 114153
diff --git a/clang/test/CodeGenCXX/constructor-init.cpp b/clang/test/CodeGenCXX/constructor-init.cpp
index 284b8b5..d610fd5 100644
--- a/clang/test/CodeGenCXX/constructor-init.cpp
+++ b/clang/test/CodeGenCXX/constructor-init.cpp
@@ -81,6 +81,38 @@
// CHECK: ret void
}
+// Make sure we initialize the vtable pointer if it's required by a
+// base initializer.
+namespace InitVTable {
+ struct A { A(int); };
+ struct B : A {
+ virtual int foo();
+ B();
+ B(int);
+ };
+
+ // CHECK: define void @_ZN10InitVTable1BC2Ev(
+ // CHECK: [[T0:%.*]] = bitcast [[B:%.*]]* [[THIS:%.*]] to i8***
+ // CHECK-NEXT: store i8** getelementptr inbounds ([3 x i8*]* @_ZTVN10InitVTable1BE, i64 0, i64 2), i8*** [[T0]]
+ // CHECK: [[VTBL:%.*]] = load i32 ([[B]]*)*** {{%.*}}
+ // CHECK-NEXT: [[FNP:%.*]] = getelementptr inbounds i32 ([[B]]*)** [[VTBL]], i64 0
+ // CHECK-NEXT: [[FN:%.*]] = load i32 ([[B]]*)** [[FNP]]
+ // CHECK-NEXT: [[ARG:%.*]] = call i32 [[FN]]([[B]]* [[THIS]])
+ // CHECK-NEXT: call void @_ZN10InitVTable1AC2Ei({{.*}}* %1, i32 [[ARG]])
+ // CHECK-NEXT: [[T0:%.*]] = bitcast [[B]]* [[THIS]] to i8***
+ // CHECK-NEXT: store i8** getelementptr inbounds ([3 x i8*]* @_ZTVN10InitVTable1BE, i64 0, i64 2), i8*** [[T0]]
+ // CHECK-NEXT: ret void
+ B::B() : A(foo()) {}
+
+ // CHECK: define void @_ZN10InitVTable1BC2Ei(
+ // CHECK: [[ARG:%.*]] = add nsw i32 {{%.*}}, 5
+ // CHECK-NEXT: call void @_ZN10InitVTable1AC2Ei({{.*}}* {{%.*}}, i32 [[ARG]])
+ // CHECK-NEXT: [[T0:%.*]] = bitcast [[B]]* {{%.*}} to i8***
+ // CHECK-NEXT: store i8** getelementptr inbounds ([3 x i8*]* @_ZTVN10InitVTable1BE, i64 0, i64 2), i8*** [[T0]]
+ // CHECK-NEXT: ret void
+ B::B(int x) : A(x + 5) {}
+}
+
template<typename T>
struct X {
X(const X &);