EricWF updated this revision to Diff 88795.
EricWF added a comment.
Remove test code that snuck in.
https://reviews.llvm.org/D29930
Files:
docs/LanguageExtensions.rst
include/clang/Basic/TokenKinds.def
include/clang/Basic/TypeTraits.h
lib/Parse/ParseDeclCXX.cpp
lib/Parse/ParseExpr.cpp
lib/Sema/SemaExprCXX.cpp
test/SemaCXX/type-traits.cpp
Index: test/SemaCXX/type-traits.cpp
===================================================================
--- test/SemaCXX/type-traits.cpp
+++ test/SemaCXX/type-traits.cpp
@@ -2048,6 +2048,8 @@
// PR25513
{ int arr[F(__is_constructible(int(int)))]; }
+
+ { int arr[T(__is_constructible(int const&, long))]; }
}
// Instantiation of __is_trivially_constructible
@@ -2078,6 +2080,46 @@
{ int arr[F((is_trivially_constructible<Abstract>::value))]; } // PR19178
}
+template <class T, class RefType = T&>
+struct ConvertsToRef {
+ operator RefType() const { return static_cast<RefType>(obj); }
+ mutable T obj = 42;
+};
+
+void reference_binds_to_temporary_checks() {
+ { int arr[F((__reference_binds_to_temporary(int&, int&)))]; }
+ { int arr[F((__reference_binds_to_temporary(int&, int&&)))]; }
+
+ { int arr[F((__reference_binds_to_temporary(int const&, int&)))]; }
+ { int arr[F((__reference_binds_to_temporary(int const&, int const&)))]; }
+ { int arr[F((__reference_binds_to_temporary(int const&, int&&)))]; }
+
+ { int arr[F((__reference_binds_to_temporary(int&, long &)))]; } // doesn't construct
+ { int arr[T((__reference_binds_to_temporary(int const&, long&)))]; }
+ { int arr[T((__reference_binds_to_temporary(int const&, long&&)))]; }
+ { int arr[T((__reference_binds_to_temporary(int&&, long&)))]; }
+
+ using LRef = ConvertsToRef<int, int&>;
+ using RRef = ConvertsToRef<int, int&&>;
+ using CLRef = ConvertsToRef<int, const int&>;
+ using LongRef = ConvertsToRef<long, long&>;
+ { int arr[T((__is_constructible(int&, LRef)))]; }
+ { int arr[F((__reference_binds_to_temporary(int&, LRef)))]; }
+
+ { int arr[T((__is_constructible(int&&, RRef)))]; }
+ { int arr[F((__reference_binds_to_temporary(int&&, RRef)))]; }
+
+ { int arr[T((__is_constructible(int const&, CLRef)))]; }
+ { int arr[F((__reference_binds_to_temporary(int&&, CLRef)))]; }
+
+ { int arr[T((__is_constructible(int const&, LongRef)))]; }
+ { int arr[T((__reference_binds_to_temporary(int const&, LongRef)))]; }
+
+ // Test that it doesn't accept non-reference types as input.
+ { int arr[F((__reference_binds_to_temporary(int, long)))]; }
+
+}
+
void array_rank() {
int t01[T(__array_rank(IntAr) == 1)];
int t02[T(__array_rank(ConstIntArAr) == 2)];
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -4564,11 +4564,14 @@
if (Kind <= UTT_Last)
return EvaluateUnaryTypeTrait(S, Kind, KWLoc, Args[0]->getType());
- if (Kind <= BTT_Last)
+ // Evaluate BTT_ReferenceBindsToTemporary along side the IsConstructible
+ // traits to avoid duplication.
+ if (Kind <= BTT_Last && Kind != BTT_ReferenceBindsToTemporary)
return EvaluateBinaryTypeTrait(S, Kind, Args[0]->getType(),
Args[1]->getType(), RParenLoc);
switch (Kind) {
+ case clang::BTT_ReferenceBindsToTemporary:
case clang::TT_IsConstructible:
case clang::TT_IsNothrowConstructible:
case clang::TT_IsTriviallyConstructible: {
@@ -4644,6 +4647,13 @@
if (Kind == clang::TT_IsConstructible)
return true;
+ if (Kind == clang::BTT_ReferenceBindsToTemporary) {
+ if (!T->isReferenceType())
+ return false;
+
+ return !Init.isDirectReferenceBinding();
+ }
+
if (Kind == clang::TT_IsNothrowConstructible)
return S.canThrow(Result.get()) == CT_Cannot;
Index: lib/Parse/ParseExpr.cpp
===================================================================
--- lib/Parse/ParseExpr.cpp
+++ lib/Parse/ParseExpr.cpp
@@ -847,6 +847,7 @@
REVERTIBLE_TYPE_TRAIT(__is_unsigned);
REVERTIBLE_TYPE_TRAIT(__is_void);
REVERTIBLE_TYPE_TRAIT(__is_volatile);
+ REVERTIBLE_TYPE_TRAIT(__reference_binds_to_temporary);
#undef REVERTIBLE_TYPE_TRAIT
#undef RTT_JOIN
}
Index: lib/Parse/ParseDeclCXX.cpp
===================================================================
--- lib/Parse/ParseDeclCXX.cpp
+++ lib/Parse/ParseDeclCXX.cpp
@@ -1431,7 +1431,8 @@
tok::kw___is_union,
tok::kw___is_unsigned,
tok::kw___is_void,
- tok::kw___is_volatile))
+ tok::kw___is_volatile,
+ tok::kw___reference_binds_to_temporary))
// GNU libstdc++ 4.2 and libc++ use certain intrinsic names as the
// name of struct templates, but some are keywords in GCC >= 4.3
// and Clang. Therefore, when we see the token sequence "struct
Index: include/clang/Basic/TypeTraits.h
===================================================================
--- include/clang/Basic/TypeTraits.h
+++ include/clang/Basic/TypeTraits.h
@@ -77,7 +77,8 @@
BTT_IsAssignable,
BTT_IsNothrowAssignable,
BTT_IsTriviallyAssignable,
- BTT_Last = BTT_IsTriviallyAssignable,
+ BTT_ReferenceBindsToTemporary,
+ BTT_Last = BTT_ReferenceBindsToTemporary,
TT_IsConstructible,
TT_IsNothrowConstructible,
TT_IsTriviallyConstructible
Index: include/clang/Basic/TokenKinds.def
===================================================================
--- include/clang/Basic/TokenKinds.def
+++ include/clang/Basic/TokenKinds.def
@@ -452,6 +452,7 @@
TYPE_TRAIT_N(__is_trivially_constructible, IsTriviallyConstructible, KEYCXX)
TYPE_TRAIT_1(__is_trivially_copyable, IsTriviallyCopyable, KEYCXX)
TYPE_TRAIT_2(__is_trivially_assignable, IsTriviallyAssignable, KEYCXX)
+TYPE_TRAIT_2(__reference_binds_to_temporary, ReferenceBindsToTemporary, KEYCXX)
KEYWORD(__underlying_type , KEYCXX)
// Embarcadero Expression Traits
Index: docs/LanguageExtensions.rst
===================================================================
--- docs/LanguageExtensions.rst
+++ docs/LanguageExtensions.rst
@@ -1023,6 +1023,11 @@
* ``__is_constructible`` (MSVC 2013, clang)
* ``__is_nothrow_constructible`` (MSVC 2013, clang)
* ``__is_assignable`` (MSVC 2015, clang)
+* ``__reference_binds_to_temporary(T, U)`` (Clang): Determines whether a
+ reference of type ``T`` bound to an expression of type ``U`` would bind to a
+ materialized temporary object. If ``T`` is not a reference type the result
+ is false. Note this trait will also return false when the initialization of
+ ``T`` from ``U`` is ill-formed.
Blocks
======
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