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ee6aa0c62e
This fixes pr13124. From the discussion at http://lists.cs.uiuc.edu/pipermail/cfe-dev/2012-June/022606.html we know that we cannot make funcions in a weak_odr vtable also weak_odr. They should remain linkonce_odr. The side effect is that we cannot emit a available_externally vtable unless we also emit a copy of the function. This also has an issue: If codegen is going to output a function, sema has to mark it used. Given llvm.org/pr9114, it looks like sema cannot be more aggressive at marking functions used because of vtables. This leaves us with a few unpleasant options: * Marking functions in vtables used if possible. This sounds a bit sloppy, so we should avoid it. * Producing available_externally vtables only when all the functions in it are already used or weak_odr. This would cover cases like -------------------- struct foo { virtual ~foo(); }; struct bar : public foo { virtual void zed(); }; void f() { foo *x(new bar); delete x; } void g(bar *x) { x->~bar(); // force the destructor to be used } -------------------------- and ---------------------------------- template<typename T> struct bar { virtual ~bar(); }; template<typename T> bar<T>::~bar() { } // make the destructor weak_odr instead of linkonce_odr extern template class bar<int>; void f() { bar<int> *x(new bar<int>); delete x; } ---------------------------- These look like corner cases, so it is unclear if it is worth it. * And finally: Just nuke this optimization. That is what this patch implements. llvm-svn: 189852
218 lines
6.6 KiB
C++
218 lines
6.6 KiB
C++
// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o %t
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// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -fhidden-weak-vtables -emit-llvm -o %t.hidden
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// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -disable-llvm-optzns -O3 -emit-llvm -o %t.opt
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// RUN: FileCheck --check-prefix=CHECK %s < %t
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// RUN: FileCheck --check-prefix=CHECK-HIDDEN %s < %t.hidden
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// RUN: FileCheck --check-prefix=CHECK-OPT %s < %t.opt
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namespace {
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struct A {
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virtual void f() { }
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};
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}
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void f() { A b; }
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struct B {
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B();
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virtual void f();
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};
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B::B() { }
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struct C : virtual B {
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C();
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virtual void f() { }
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};
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C::C() { }
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struct D {
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virtual void f();
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};
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void D::f() { }
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static struct : D { } e;
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// The destructor is the key function.
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template<typename T>
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struct E {
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virtual ~E();
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};
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template<typename T> E<T>::~E() { }
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// Anchor is the key function
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template<>
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struct E<char> {
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virtual void anchor();
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};
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void E<char>::anchor() { }
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template struct E<short>;
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extern template struct E<int>;
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void use_E() {
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E<int> ei;
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(void)ei;
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E<long> el;
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(void)el;
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}
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// No key function
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template<typename T>
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struct F {
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virtual void foo() { }
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};
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// No key function
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template<>
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struct F<char> {
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virtual void foo() { }
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};
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template struct F<short>;
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extern template struct F<int>;
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void use_F() {
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F<char> fc;
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fc.foo();
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F<int> fi;
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fi.foo();
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F<long> fl;
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(void)fl;
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}
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// B has a key function that is not defined in this translation unit so its vtable
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// has external linkage.
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// CHECK-DAG: @_ZTV1B = external unnamed_addr constant
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// C has no key function, so its vtable should have weak_odr linkage
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// and hidden visibility (rdar://problem/7523229).
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// CHECK-DAG: @_ZTV1C = linkonce_odr unnamed_addr constant
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// CHECK-DAG: @_ZTS1C = linkonce_odr constant
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// CHECK-DAG: @_ZTI1C = linkonce_odr unnamed_addr constant
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// CHECK-DAG: @_ZTT1C = linkonce_odr unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTV1C = linkonce_odr hidden unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTS1C = linkonce_odr constant
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// CHECK-HIDDEN-DAG: @_ZTI1C = linkonce_odr hidden unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTT1C = linkonce_odr hidden unnamed_addr constant
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// D has a key function that is defined in this translation unit so its vtable is
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// defined in the translation unit.
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// CHECK-DAG: @_ZTV1D = unnamed_addr constant
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// CHECK-DAG: @_ZTS1D = constant
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// CHECK-DAG: @_ZTI1D = unnamed_addr constant
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// E<char> is an explicit specialization with a key function defined
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// in this translation unit, so its vtable should have external
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// linkage.
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// CHECK-DAG: @_ZTV1EIcE = unnamed_addr constant
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// CHECK-DAG: @_ZTS1EIcE = constant
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// CHECK-DAG: @_ZTI1EIcE = unnamed_addr constant
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// E<short> is an explicit template instantiation with a key function
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// defined in this translation unit, so its vtable should have
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// weak_odr linkage.
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// CHECK-DAG: @_ZTV1EIsE = weak_odr unnamed_addr constant
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// CHECK-DAG: @_ZTS1EIsE = weak_odr constant
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// CHECK-DAG: @_ZTI1EIsE = weak_odr unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTV1EIsE = weak_odr unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTS1EIsE = weak_odr constant
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// CHECK-HIDDEN-DAG: @_ZTI1EIsE = weak_odr unnamed_addr constant
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// F<short> is an explicit template instantiation without a key
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// function, so its vtable should have weak_odr linkage
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// CHECK-DAG: @_ZTV1FIsE = weak_odr unnamed_addr constant
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// CHECK-DAG: @_ZTS1FIsE = weak_odr constant
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// CHECK-DAG: @_ZTI1FIsE = weak_odr unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTV1FIsE = weak_odr unnamed_addr constant
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// CHECK-HIDDEN-DAG: @_ZTS1FIsE = weak_odr constant
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// CHECK-HIDDEN-DAG: @_ZTI1FIsE = weak_odr unnamed_addr constant
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// E<long> is an implicit template instantiation with a key function
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// defined in this translation unit, so its vtable should have
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// linkonce_odr linkage.
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// CHECK-DAG: @_ZTV1EIlE = linkonce_odr unnamed_addr constant
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// CHECK-DAG: @_ZTS1EIlE = linkonce_odr constant
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// CHECK-DAG: @_ZTI1EIlE = linkonce_odr unnamed_addr constant
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// F<long> is an implicit template instantiation with no key function,
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// so its vtable should have linkonce_odr linkage.
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// CHECK-DAG: @_ZTV1FIlE = linkonce_odr unnamed_addr constant
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// CHECK-DAG: @_ZTS1FIlE = linkonce_odr constant
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// CHECK-DAG: @_ZTI1FIlE = linkonce_odr unnamed_addr constant
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// F<int> is an explicit template instantiation declaration without a
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// key function, so its vtable should have external linkage.
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// CHECK-DAG: @_ZTV1FIiE = external unnamed_addr constant
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// CHECK-OPT-DAG: @_ZTV1FIiE = external unnamed_addr constant
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// E<int> is an explicit template instantiation declaration. It has a
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// key function that is not instantiated, so we should only reference
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// its vtable, not define it.
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// CHECK-DAG: @_ZTV1EIiE = external unnamed_addr constant
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// CHECK-OPT-DAG: @_ZTV1EIiE = external unnamed_addr constant
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// The anonymous struct for e has no linkage, so the vtable should have
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// internal linkage.
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// CHECK-DAG: @"_ZTV3$_0" = internal unnamed_addr constant
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// CHECK-DAG: @"_ZTS3$_0" = internal constant
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// CHECK-DAG: @"_ZTI3$_0" = internal unnamed_addr constant
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// The A vtable should have internal linkage since it is inside an anonymous
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// namespace.
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// CHECK-DAG: @_ZTVN12_GLOBAL__N_11AE = internal unnamed_addr constant
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// CHECK-DAG: @_ZTSN12_GLOBAL__N_11AE = internal constant
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// CHECK-DAG: @_ZTIN12_GLOBAL__N_11AE = internal unnamed_addr constant
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// F<char> is an explicit specialization without a key function, so
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// its vtable should have linkonce_odr linkage.
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// CHECK-DAG: @_ZTV1FIcE = linkonce_odr unnamed_addr constant
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// CHECK-DAG: @_ZTS1FIcE = linkonce_odr constant
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// CHECK-DAG: @_ZTI1FIcE = linkonce_odr unnamed_addr constant
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// CHECK-DAG: @_ZTV1GIiE = linkonce_odr unnamed_addr constant
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template <typename T>
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class G {
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public:
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G() {}
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virtual void f0();
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virtual void f1();
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};
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template <>
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void G<int>::f1() {}
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template <typename T>
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void G<T>::f0() {}
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void G_f0() { new G<int>(); }
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// H<int> has a key function without a body but it's a template instantiation
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// so its VTable must be emitted.
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// CHECK-DAG: @_ZTV1HIiE = linkonce_odr unnamed_addr constant
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template <typename T>
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class H {
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public:
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virtual ~H();
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};
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void use_H() {
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H<int> h;
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}
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// I<int> has an explicit instantiation declaration and needs a VTT and
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// construction vtables.
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// CHECK-DAG: @_ZTV1IIiE = external unnamed_addr constant
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// CHECK-DAG: @_ZTT1IIiE = external unnamed_addr constant
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// CHECK-NOT: @_ZTC1IIiE
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//
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// CHECK-OPT-DAG: @_ZTV1IIiE = external unnamed_addr constant
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// CHECK-OPT-DAG: @_ZTT1IIiE = external unnamed_addr constant
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struct VBase1 { virtual void f(); }; struct VBase2 : virtual VBase1 {};
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template<typename T>
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struct I : VBase2 {};
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extern template struct I<int>;
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I<int> i;
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