88d292ccb8
"used" (e.g., we will refer to the vtable in the generated code) and when they are defined (i.e., because we've seen the key function definition). Previously, we were effectively tracking "potential definitions" rather than uses, so we were a bit too eager about emitting vtables for classes without key functions. The new scheme: - For every use of a vtable, Sema calls MarkVTableUsed() to indicate the use. For example, this occurs when calling a virtual member function of the class, defining a constructor of that class type, dynamic_cast'ing from that type to a derived class, casting to/through a virtual base class, etc. - For every definition of a vtable, Sema calls MarkVTableUsed() to indicate the definition. This happens at the end of the translation unit for classes whose key function has been defined (so we can delay computation of the key function; see PR6564), and will also occur with explicit template instantiation definitions. - For every vtable defined/used, we mark all of the virtual member functions of that vtable as defined/used, unless we know that the key function is in another translation unit. This instantiates virtual member functions when needed. - At the end of the translation unit, Sema tells CodeGen (via the ASTConsumer) which vtables must be defined (CodeGen will define them) and which may be used (for which CodeGen will define the vtables lazily). From a language perspective, both the old and the new schemes are permissible: we're allowed to instantiate virtual member functions whenever we want per the standard. However, all other C++ compilers were more lazy than we were, and our eagerness was both a performance issue (we instantiated too much) and a portability problem (we broke Boost test cases, which now pass). Notes: (1) There's a ton of churn in the tests, because the order in which vtables get emitted to IR has changed. I've tried to isolate some of the larger tests from these issues. (2) Some diagnostics related to implicitly-instantiated/implicitly-defined virtual member functions have moved to the point of first use/definition. It's better this way. (3) I could use a review of the places where we MarkVTableUsed, to see if I missed any place where the language effectively requires a vtable. Fixes PR7114 and PR6564. llvm-svn: 103718
138 lines
1.9 KiB
C++
138 lines
1.9 KiB
C++
// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s
|
|
|
|
namespace Test1 {
|
|
|
|
// Check that we emit a non-virtual thunk for C::f.
|
|
|
|
struct A {
|
|
virtual void f();
|
|
};
|
|
|
|
struct B {
|
|
virtual void f();
|
|
};
|
|
|
|
struct C : A, B {
|
|
virtual void c();
|
|
|
|
virtual void f();
|
|
};
|
|
|
|
// CHECK: define void @_ZThn8_N5Test11C1fEv(
|
|
void C::f() { }
|
|
|
|
}
|
|
|
|
namespace Test2 {
|
|
|
|
// Check that we emit a thunk for B::f since it's overriding a virtual base.
|
|
|
|
struct A {
|
|
virtual void f();
|
|
};
|
|
|
|
struct B : virtual A {
|
|
virtual void b();
|
|
virtual void f();
|
|
};
|
|
|
|
// CHECK: define void @_ZTv0_n24_N5Test21B1fEv(
|
|
void B::f() { }
|
|
|
|
}
|
|
|
|
namespace Test3 {
|
|
|
|
// Check that we emit a covariant thunk for B::f.
|
|
|
|
struct V1 { };
|
|
struct V2 : virtual V1 { };
|
|
|
|
struct A {
|
|
virtual V1 *f();
|
|
};
|
|
|
|
struct B : A {
|
|
virtual void b();
|
|
|
|
virtual V2 *f();
|
|
};
|
|
|
|
// CHECK: define %{{.*}}* @_ZTch0_v0_n24_N5Test31B1fEv(
|
|
V2 *B::f() { return 0; }
|
|
|
|
}
|
|
|
|
namespace Test4 {
|
|
|
|
// Check that the thunk for 'C::f' has the same visibility as the function itself.
|
|
|
|
struct A {
|
|
virtual void f();
|
|
};
|
|
|
|
struct B {
|
|
virtual void f();
|
|
};
|
|
|
|
struct __attribute__((visibility("protected"))) C : A, B {
|
|
virtual void c();
|
|
|
|
virtual void f();
|
|
};
|
|
|
|
// CHECK: define protected void @_ZThn8_N5Test41C1fEv(
|
|
void C::f() { }
|
|
|
|
}
|
|
|
|
// This is from Test5:
|
|
// CHECK: define linkonce_odr void @_ZTv0_n24_N5Test51B1fEv
|
|
// CHECK: define internal void @_ZThn8_N12_GLOBAL__N_11C1fEv(
|
|
|
|
// Check that the thunk gets internal linkage.
|
|
namespace {
|
|
|
|
struct A {
|
|
virtual void f();
|
|
};
|
|
|
|
struct B {
|
|
virtual void f();
|
|
};
|
|
|
|
struct C : A, B {
|
|
virtual void c();
|
|
|
|
virtual void f();
|
|
};
|
|
|
|
void C::f() { }
|
|
|
|
}
|
|
|
|
// Force C::f to be used.
|
|
void f() {
|
|
C c;
|
|
|
|
c.f();
|
|
}
|
|
|
|
namespace Test5 {
|
|
|
|
// Check that the thunk for 'B::f' gets the same linkage as the function itself.
|
|
struct A {
|
|
virtual void f();
|
|
};
|
|
|
|
struct B : virtual A {
|
|
virtual void f() { }
|
|
};
|
|
|
|
void f(B b) {
|
|
b.f();
|
|
}
|
|
}
|
|
|
|
|