MinGW neither imports nor exports such methods. The import bit was
committed earlier, in r221154, and this takes care of the export part.
This also partially fixes PR22591.
llvm-svn: 229922
The llvm IR until recently had no support for comdats. This was a problem when
targeting C++ on ELF/COFF as just using weak linkage would cause quite a bit of
dead bits to remain on the executable (unless -ffunction-sections,
-fdata-sections and --gc-sections were used).
To fix the problem, llvm's codegen will just assume that any weak or linkonce
that is not in an explicit comdat should be output in one with the same name as
the global.
This unfortunately breaks cases like pr19848 where a weak symbol is not
xpected to be part of any comdat.
Now that we have explicit comdats in the IR, we can finally get both cases
right.
This first patch just makes clang give explicit comdats to GlobalValues where
t is allowed to.
A followup patch to llvm will then stop implicitly producing comdats.
llvm-svn: 225705
It turns out that MinGW never dllimports of exports inline functions.
This means that code compiled with Clang would fail to link with
MinGW-compiled libraries since we might try to import functions that
are not imported.
To fix this, make Clang never dllimport inline functions when targeting
MinGW.
llvm-svn: 221154
Clang would previously assert on the following code when targeting MinGW:
struct __declspec(dllimport) S {
virtual ~S();
};
S::~S() {}
Because ~S is a key function and the class is dllimport, we would try to emit a
strong definition of the vtable, with dllimport - which is a conflict. We
should not emit strong vtable definitions for imported classes.
Differential Revision: http://reviews.llvm.org/D5944
llvm-svn: 220532
This changes the scope discriminator's behavior to start at '1' instead
of '0'. Symbol table diffing, for ABI compatibility testing, kept
finding these as false positives.
llvm-svn: 219075
We would previously assert (a decl cannot have two DLL attributes) on this code:
template <typename T> struct __declspec(dllimport) S { T f() { return T(); } };
template struct __declspec(dllexport) S<int>;
The problem was that when instantiating, we would take the attribute from the
template even if the instantiation itself already had an attribute.
Also, don't inherit DLL attributes from the template to its members before
instantiation, as the attribute may change.
I couldn't figure out what MinGW does here, so I'm leaving that open. At least
we're not asserting anymore.
llvm-svn: 216340
This matches MSVC's logic, which seems to be that when the friend
declaration is qualified, it cannot be a declaration of a new symbol
and so the dll linkage doesn't change.
Differential Revision: http://reviews.llvm.org/D4764
llvm-svn: 214774
Because references must be initialized using some evaluated expression, they
must point to something, and a callee can assume the reference parameter is
dereferenceable. Taking advantage of a new attribute just added to LLVM, mark
them as such.
Because dereferenceability in addrspace(0) implies nonnull in the backend, we
don't need both attributes. However, we need to know the size of the object to
use the dereferenceable attribute, so for incomplete types we still emit only
nonnull.
llvm-svn: 213386
This is a follow-up to David's r211677. For the following code,
we would end up referring to 'foo' in the initializer for 'arr',
and then fail to link, because 'foo' is dllimport and needs to be
accessed through the __imp_?foo.
__declspec(dllimport) extern const char foo[];
const char* f() {
static const char* const arr[] = { foo };
return arr[0];
}
Differential Revision: http://reviews.llvm.org/D4299
llvm-svn: 211736
Consider the following code:
template <typename T> class Base {};
class __declspec(dllexport) class Derived : public Base<int> {}
When the base of an exported or imported class is a class template
specialization, MSVC will propagate the dll attribute to the base.
In the example code, Base<int> becomes a dllexported class.
This commit makes Clang do the proopagation when the base hasn't been
instantiated yet, and warns about it being unsupported otherwise.
This is different from MSVC, which allows changing a specialization
back and forth between dllimport and dllexport and seems to let the
last one win. Changing the dll attribute after instantiation would be
hard for us, and doesn't seem to come up in practice, so I think this
is a reasonable limitation to have.
MinGW doesn't do this kind of propagation.
Differential Revision: http://reviews.llvm.org/D4264
llvm-svn: 211725
Current MSVC versions don't have move assignment operators, so we
can't rely on them being available in the dll. If we have the
definition, we can just use that directly. This breaks pointer
equality, but should work fine otherwise.
When there is an MSVC version that supports move assignment,
we can key this off the -fmsc-ver option.
http://reviews.llvm.org/D4105
llvm-svn: 210715
We would previously assert if the initializer was dependent. I also think that
checking isConstantInitializer is more correct here than checkInitIsICE.
llvm-svn: 210505
As suggested by Reid:
- class has GVA_Internal linkage -> internal
- thunk has return adjustment -> weak_odr, to handle evil corner case [1]
- all other normal methods -> linkonce_odr
1. Evil corner case:
struct Incomplete;
struct A { int a; virtual A *bar(); };
struct B { int b; virtual B *foo(Incomplete); };
struct C : A, B { int c; virtual C *foo(Incomplete); };
C c;
Here, the thunk for C::foo() will be emitted when C::foo() is defined, which
might be in a different translation unit, so it needs to be weak_odr.
Differential Revision: http://reviews.llvm.org/D3992
llvm-svn: 210368
This allows us to compile the following kind of code, which occurs in MSVC
headers:
template <typename> struct S {
__declspec(dllimport) static int x;
};
template <typename T> int S<T>::x;
The definition works similarly to a dllimport inline function definition and
gets available_externally linkage.
Differential Revision: http://reviews.llvm.org/D3998
llvm-svn: 210141
This implements the central part of support for dllimport/dllexport on
classes: allowing the attribute on class declarations, inheriting it
to class members, and forcing emission of exported members. It's based
on Nico Rieck's patch from http://reviews.llvm.org/D1099.
This patch doesn't propagate dllexport to bases that are template
specializations, which is an interesting problem. It also doesn't
look at the rules when redeclaring classes with different attributes,
I'd like to do that separately.
Differential Revision: http://reviews.llvm.org/D3877
llvm-svn: 209908
Hans Wennborg