Summary:
Currently parts of the SFINAE on tuples default constructor always gets evaluated even when the default constructor is never called or instantiated. This can cause a hard compile error when a tuple is created with types that do not have a default constructor. Below is a self contained example using a pair like class. This code will not compile but probably should.
```
#include <type_traits>
template <class T>
struct IllFormedDefaultImp {
IllFormedDefaultImp(T x) : value(x) {}
constexpr IllFormedDefaultImp() {}
T value;
};
typedef IllFormedDefaultImp<int &> IllFormedDefault;
template <class T, class U>
struct pair
{
template <bool Dummy = true,
class = typename std::enable_if<
std::is_default_constructible<T>::value
&& std::is_default_constructible<U>::value
&& Dummy>::type
>
constexpr pair() : first(), second() {}
pair(T const & t, U const & u) : first(t), second(u) {}
T first;
U second;
};
int main()
{
int x = 1;
IllFormedDefault v(x);
pair<IllFormedDefault, IllFormedDefault> p(v, v);
}
```
One way to fix this is to use `Dummy` in a more involved way in the constructor SFINAE. The following patch fixes these sorts of hard compile errors for tuple.
Reviewers: mclow.lists, rsmith, K-ballo, EricWF
Reviewed By: EricWF
Subscribers: ldionne, cfe-commits
Differential Revision: http://reviews.llvm.org/D7569
llvm-svn: 230120
Summary: No declaration for the type `tuple` is given in c++03 or c++98 modes. Mark all tests that use the actual `tuple` type as UNSUPPORTED.
Reviewers: jroelofs, mclow.lists, danalbert
Reviewed By: danalbert
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D5956
llvm-svn: 229808
Summary:
This patch introduces some black magic to detect const and volatile qualified function types such as `void () const`.
The patch works in the following way:
We first rule out any type that satisfies on of the following. These restrictions are important so that the test below works properly.
* `is_class<_Tp>::value`
* `is_union<_Tp>::value`
* `is_void<_Tp>::value`
* `is_reference<_Tp>::value`
* `__is_nullptr_t<_Tp>::value`
If none of the above is true we perform overload resolution on `__source<_Tp>(0)` to determine the return type.
* If `_Tp&` is well-formed we select `_Tp& __source(int)`. `_Tp&` is only ill formed for cv void types and cv/ref qualified function types.
* Otherwise we select `__dummy_type __source(...)`. Since we know `_Tp` cannot be void then it must be a function type.
let `R` be the returned from `__source<_Tp>(0)`.
We perform overload resolution on `__test<_Tp>(R)`.
* If `R` is `__dummy_type` we call `true_type __test(__dummy_type)`.
* if `R` is `_Tp&` and `_Tp&` decays to `_Tp*` we call `true_type __test(_Tp*)`. Only references to function types decay to a pointer of the same type.
* In all other cases we call `false_type __test(...)`.
`__source<_Tp>(0)` will try and form `_Tp&` in the return type. if `_Tp&` is not well formed the return type of `__source<_Tp>(0)` will be dummy type. `_Tp&` is only ill-formed for cv/ref qualified function types (and void which is dealt with elsewhere).
This fixes PR20084 - http://llvm.org/bugs/show_bug.cgi?id=20084
Reviewers: rsmith, K-ballo, mclow.lists
Reviewed By: mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7573
llvm-svn: 229696
Summary:
This patch is pretty simple. It just adds the _v traits from <ratio>.
The draft can be found here.
Reviewers: jroelofs, K-ballo, mclow.lists
Reviewed By: mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7351
llvm-svn: 229509
Summary:
Hello Howard,
While running the libc++ tests on our ARM boards, we encounter sporadic failures of the two tests:
test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
The worker thread might not finish yet when the main thread checks its result.
I filed the bug 21998 for this case: http://llvm.org/bugs/show_bug.cgi?id=21998
Would you be able to review this please?
Thank you.
Oleg
Reviewers: howard.hinnant, mclow.lists, danalbert, jroelofs, EricWF
Reviewed By: jroelofs, EricWF
Subscribers: EricWF, mclow.lists, aemerson, llvm-commits
Differential Revision: http://reviews.llvm.org/D6750
llvm-svn: 228783
Summary:
The bug can be found here: http://llvm.org/bugs/show_bug.cgi?id=22468
`__invoke_void_return_wrapper` is needed to properly handle calling a function that returns a value but where the std::function return type is void. Without this '-Wsystem-headers' will cause `function::operator()(...)` to not compile.
Reviewers: eugenis, K-ballo, mclow.lists
Reviewed By: mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7444
llvm-svn: 228705
Summary:
The requirement on the `Size` type passed to *_n algorithms is that it is convertible to an integral type. This means we can't use a variable of type `Size` directly. Instead we need to convert it to an integral type first. The problem is finding out what integral type to convert it to. `__convert_to_integral` figures out what integral type to convert it to and performs the conversion, It also promotes the resulting integral type so that it is at least as big as an integer. `__convert_to_integral` also has a special case for converting enums. This should only work on non-scoped enumerations because it does not apply an explicit conversion from the enum to its underlying type.
Reviewers: chandlerc, mclow.lists
Reviewed By: mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7449
llvm-svn: 228704
he following snippet doesn't build when using gcc and libc++:
#include <string>
void f(const std::string& s) { s.begin(); }
#include <vector>
void AppendTo(const std::vector<char>& v) { v.begin(); }
The problem is that __wrap_iter has a private constructor. It lists vector<>
and basic_string<> as friends, but gcc seems to ignore this for vector<> for
some reason. Declaring vector before the friend declaration in __wrap_iter is
enough to work around this problem, so do that. With this patch, I'm able to
build chromium/android with libc++. Without it, two translation units fail to
build. (iosfwd already provides a forward declaration of basic_string.)
As far as I can tell, this is due to a gcc bug, which I filed as
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64816.
Fixes PR22355.
http://reviews.llvm.org/D7201
llvm-svn: 227226
Marshall Clow