Implement std::experimental::propagate_const from LFTS v2

Summary:
An implementation of std::experimental::propagate_const from Library Fundamentals Technical Specification v2.

No tests are provided for disallowed types like fancy pointers or function pointers as no code was written to handle these.

Reviewers: EricWF, mclow.lists

Differential Revision: http://reviews.llvm.org/D12486

llvm-svn: 273122

1 files changed, 119 insertions, 0 deletions

diff --git a/libcxx/test/support/propagate_const_helpers.h b/libcxx/test/support/propagate_const_helpers.h
new file mode 100644
index 00000000000..581565a3427
--- /dev/null
+++ b/libcxx/test/support/propagate_const_helpers.h
@@ -0,0 +1,119 @@
+ // A lightweight class, with pointer-like methods, that contains an int
+struct X
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+
+    constexpr X(int i) : i_(i) {}
+};
+
+struct XWithImplicitIntStarConversion
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+    constexpr operator int* () { return &i_; }
+
+    constexpr XWithImplicitIntStarConversion(int i) : i_(i) {}
+};
+
+struct XWithImplicitConstIntStarConversion
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+    constexpr operator const int* () const { return &i_; }
+
+    constexpr XWithImplicitConstIntStarConversion(int i) : i_(i) {}
+};
+
+struct ExplicitX
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+
+    constexpr explicit ExplicitX(int i) : i_(i) {}
+};
+
+struct MoveConstructibleFromX
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+
+    constexpr MoveConstructibleFromX(int i) : i_(i) {}
+    constexpr MoveConstructibleFromX(X&& x) : i_(x.i_) {}
+};
+
+struct ExplicitMoveConstructibleFromX
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+
+    constexpr ExplicitMoveConstructibleFromX(int i) : i_(i) {}
+    constexpr explicit ExplicitMoveConstructibleFromX(X&& x) : i_(x.i_) {}
+};
+
+struct CopyConstructibleFromX
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+
+    constexpr CopyConstructibleFromX(int i) : i_(i) {}
+    constexpr CopyConstructibleFromX(const X& x) : i_(x.i_) {}
+};
+
+struct ExplicitCopyConstructibleFromX
+{
+    int i_;
+
+    constexpr const int &operator*() const { return i_; }
+    constexpr int &operator*() { return i_; }
+    constexpr const int *get() const { return &i_; }
+    constexpr int *get() { return &i_; }
+    constexpr const int *operator->() const { return &i_; }
+    constexpr int *operator->() { return &i_; }
+
+    constexpr ExplicitCopyConstructibleFromX(int i) : i_(i) {}
+    constexpr explicit ExplicitCopyConstructibleFromX(const X& x) : i_(x.i_) {}
+};
+