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884772fdd6
I believe this is what the original commit (33e022650adee965c65f9aea086ee74f3fd1bad5) was trying to do. This fixes a bug where clang removes the attribute from a declaration that follows a declaration directly contained in a linkage-specification. rdar://61865848
66 lines
3.2 KiB
C++
66 lines
3.2 KiB
C++
// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -verify -std=c++11 %s
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// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -verify -std=c++11 %s -fexperimental-new-constant-interpreter
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static int test0 __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
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static void test1() __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
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namespace test2 __attribute__((weak)) { // expected-warning {{'weak' attribute only applies to variables, functions, and classes}}
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}
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namespace {
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int test3 __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
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void test4() __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
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}
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struct Test5 {
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static void test5() __attribute__((weak)); // no error
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};
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namespace {
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struct Test6 {
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static void test6() __attribute__((weak)); // expected-error {{weak declaration cannot have internal linkage}}
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};
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}
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// GCC rejects the instantiation with the internal type, but some existing
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// code expects it. It is also not that different from giving hidden visibility
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// to parts of a template that have explicit default visibility, so we accept
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// this.
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template <class T> struct Test7 {
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void test7() __attribute__((weak)) {}
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static int var __attribute__((weak));
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};
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template <class T>
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int Test7<T>::var;
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namespace { class Internal {}; }
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template struct Test7<Internal>;
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template struct Test7<int>;
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class __attribute__((weak)) Test8 {}; // OK
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__attribute__((weak)) auto Test9 = Internal(); // expected-error {{weak declaration cannot have internal linkage}}
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[[gnu::weak]] void weak_function();
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struct WithWeakMember {
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[[gnu::weak]] void weak_method();
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[[gnu::weak]] virtual void virtual_weak_method();
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};
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constexpr bool weak_function_is_non_null = &weak_function != nullptr; // expected-error {{must be initialized by a constant expression}}
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// expected-note@-1 {{comparison against address of weak declaration '&weak_function' can only be performed at runtime}}
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constexpr bool weak_method_is_non_null = &WithWeakMember::weak_method != nullptr; // expected-error {{must be initialized by a constant expression}}
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// expected-note@-1 {{comparison against pointer to weak member 'WithWeakMember::weak_method' can only be performed at runtime}}
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// GCC accepts this and says the result is always non-null. That's consistent
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// with the ABI rules for member pointers, but seems unprincipled, so we do not
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// follow it for now.
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// TODO: Consider warning on such comparisons, as they do not test whether the
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// virtual member function is present.
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constexpr bool virtual_weak_method_is_non_null = &WithWeakMember::virtual_weak_method != nullptr; // expected-error {{must be initialized by a constant expression}}
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// expected-note@-1 {{comparison against pointer to weak member 'WithWeakMember::virtual_weak_method' can only be performed at runtime}}
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// Check that no warnings are emitted.
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extern "C" int g0;
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extern int g0 __attribute__((weak_import));
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extern "C" int g1 = 0; // expected-note {{previous definition is here}}
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extern int g1 __attribute__((weak_import)); // expected-warning {{attribute declaration must precede definition}}
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