<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">Hi Akira,</div><div class="gmail_quote"><br></div><div class="gmail_quote">This change has broken the C++ versions of these type traits for classes with volatile members. Such classes are required to claim to be trivial per C++ DR 2094 (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#2094">http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#2094</a>) but return false from isNonTrivialToPrimitiveCopy().</div><div class="gmail_quote"><br></div><div class="gmail_quote">Also, exposing these __has_* traits more widely seems like a backwards step to me: these traits are deprecated, near-useless, and we're trying to remove them. No code should be using them under any circumstances; the __is_* traits should be used instead.</div><div class="gmail_quote"><br></div><div class="gmail_quote">On 27 March 2018 at 17:12, Akira Hatanaka via cfe-commits <span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Author: ahatanak<br>
Date: Tue Mar 27 17:12:08 2018<br>
New Revision: 328680<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=328680&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project?rev=328680&view=rev</a><br>
Log:<br>
[ObjC] Make C++ triviality type traits available to non-trivial C<br>
structs.<br>
<br>
r326307 and r327870 made changes that allowed using non-trivial C<br>
structs with fields qualified with __strong or __weak. This commit makes<br>
the following C++ triviality type traits available to non-trivial C<br>
structs:<br>
<br>
__has_trivial_assign<br>
__has_trivial_move_assign<br>
__has_trivial_copy<br>
__has_trivial_move_constructor<br>
__has_trivial_constructor<br>
__has_trivial_destructor<br>
<br>
rdar://problem/33599681<br>
<br>
Differential Revision: <a href="https://reviews.llvm.org/D44913" rel="noreferrer" target="_blank">https://reviews.llvm.org/<wbr>D44913</a><br>
<br>
Added:<br>
cfe/trunk/test/SemaObjC/non-<wbr>trivial-struct-traits.m<br>
Modified:<br>
cfe/trunk/include/clang/Basic/<wbr>TokenKinds.def<br>
cfe/trunk/lib/Sema/<wbr>SemaExprCXX.cpp<br>
<br>
Modified: cfe/trunk/include/clang/Basic/<wbr>TokenKinds.def<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/TokenKinds.def?rev=328680&r1=328679&r2=328680&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/cfe/trunk/include/<wbr>clang/Basic/TokenKinds.def?<wbr>rev=328680&r1=328679&r2=<wbr>328680&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- cfe/trunk/include/clang/Basic/<wbr>TokenKinds.def (original)<br>
+++ cfe/trunk/include/clang/Basic/<wbr>TokenKinds.def Tue Mar 27 17:12:08 2018<br>
@@ -433,12 +433,12 @@ TYPE_TRAIT_1(__has_nothrow_<wbr>assign, HasNo<br>
TYPE_TRAIT_1(__has_nothrow_<wbr>move_assign, HasNothrowMoveAssign, KEYCXX)<br>
TYPE_TRAIT_1(__has_nothrow_<wbr>copy, HasNothrowCopy, KEYCXX)<br>
TYPE_TRAIT_1(__has_nothrow_<wbr>constructor, HasNothrowConstructor, KEYCXX)<br>
-TYPE_TRAIT_1(__has_trivial_<wbr>assign, HasTrivialAssign, KEYCXX)<br>
-TYPE_TRAIT_1(__has_trivial_<wbr>move_assign, HasTrivialMoveAssign, KEYCXX)<br>
-TYPE_TRAIT_1(__has_trivial_<wbr>copy, HasTrivialCopy, KEYCXX)<br>
-TYPE_TRAIT_1(__has_trivial_<wbr>constructor, HasTrivialDefaultConstructor, KEYCXX)<br>
-TYPE_TRAIT_1(__has_trivial_<wbr>move_constructor, HasTrivialMoveConstructor, KEYCXX)<br>
-TYPE_TRAIT_1(__has_trivial_<wbr>destructor, HasTrivialDestructor, KEYCXX)<br>
+TYPE_TRAIT_1(__has_trivial_<wbr>assign, HasTrivialAssign, KEYALL)<br>
+TYPE_TRAIT_1(__has_trivial_<wbr>move_assign, HasTrivialMoveAssign, KEYALL)<br>
+TYPE_TRAIT_1(__has_trivial_<wbr>copy, HasTrivialCopy, KEYALL)<br>
+TYPE_TRAIT_1(__has_trivial_<wbr>constructor, HasTrivialDefaultConstructor, KEYALL)<br>
+TYPE_TRAIT_1(__has_trivial_<wbr>move_constructor, HasTrivialMoveConstructor, KEYALL)<br>
+TYPE_TRAIT_1(__has_trivial_<wbr>destructor, HasTrivialDestructor, KEYALL)<br>
TYPE_TRAIT_1(__has_virtual_<wbr>destructor, HasVirtualDestructor, KEYCXX)<br>
TYPE_TRAIT_1(__is_abstract, IsAbstract, KEYCXX)<br>
TYPE_TRAIT_1(__is_aggregate, IsAggregate, KEYCXX)<br>
<br>
Modified: cfe/trunk/lib/Sema/<wbr>SemaExprCXX.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=328680&r1=328679&r2=328680&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/cfe/trunk/lib/Sema/<wbr>SemaExprCXX.cpp?rev=328680&r1=<wbr>328679&r2=328680&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- cfe/trunk/lib/Sema/<wbr>SemaExprCXX.cpp (original)<br>
+++ cfe/trunk/lib/Sema/<wbr>SemaExprCXX.cpp Tue Mar 27 17:12:08 2018<br>
@@ -4513,6 +4513,8 @@ static bool EvaluateUnaryTypeTrait(Sema<br>
// does not correctly compute triviality in the presence of multiple special<br>
// members of the same kind. Revisit this once the g++ bug is fixed.<br>
case UTT_<wbr>HasTrivialDefaultConstructor:<br>
+ if (T.<wbr>isNonTrivialToPrimitiveDefault<wbr>Initialize())<br>
+ return false;<br>
// <a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html" rel="noreferrer" target="_blank">http://gcc.gnu.org/onlinedocs/<wbr>gcc/Type-Traits.html</a>:<br>
// If __is_pod (type) is true then the trait is true, else if type is<br>
// a cv class or union type (or array thereof) with a trivial default<br>
@@ -4524,6 +4526,8 @@ static bool EvaluateUnaryTypeTrait(Sema<br>
!RD-><wbr>hasNonTrivialDefaultConstructo<wbr>r();<br>
return false;<br>
case UTT_HasTrivialMoveConstructor:<br>
+ if (T.<wbr>isNonTrivialToPrimitiveDestruc<wbr>tiveMove())<br>
+ return false;<br>
// This trait is implemented by MSVC 2012 and needed to parse the<br>
// standard library headers. Specifically this is used as the logic<br>
// behind std::is_trivially_move_<wbr>constructible (20.9.4.3).<br>
@@ -4533,6 +4537,8 @@ static bool EvaluateUnaryTypeTrait(Sema<br>
return RD->hasTrivialMoveConstructor(<wbr>) && !RD-><wbr>hasNonTrivialMoveConstructor()<wbr>;<br>
return false;<br>
case UTT_HasTrivialCopy:<br>
+ if (T.<wbr>isNonTrivialToPrimitiveCopy())<br>
+ return false;<br>
// <a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html" rel="noreferrer" target="_blank">http://gcc.gnu.org/onlinedocs/<wbr>gcc/Type-Traits.html</a>:<br>
// If __is_pod (type) is true or type is a reference type then<br>
// the trait is true, else if type is a cv class or union type<br>
@@ -4545,6 +4551,8 @@ static bool EvaluateUnaryTypeTrait(Sema<br>
!RD-><wbr>hasNonTrivialCopyConstructor()<wbr>;<br>
return false;<br>
case UTT_HasTrivialMoveAssign:<br>
+ if (T.<wbr>isNonTrivialToPrimitiveDestruc<wbr>tiveMove())<br>
+ return false;<br>
// This trait is implemented by MSVC 2012 and needed to parse the<br>
// standard library headers. Specifically it is used as the logic<br>
// behind std::is_trivially_move_<wbr>assignable (20.9.4.3)<br>
@@ -4554,6 +4562,8 @@ static bool EvaluateUnaryTypeTrait(Sema<br>
return RD->hasTrivialMoveAssignment() && !RD-><wbr>hasNonTrivialMoveAssignment();<br>
return false;<br>
case UTT_HasTrivialAssign:<br>
+ if (T.<wbr>isNonTrivialToPrimitiveCopy())<br>
+ return false;<br>
// <a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html" rel="noreferrer" target="_blank">http://gcc.gnu.org/onlinedocs/<wbr>gcc/Type-Traits.html</a>:<br>
// If type is const qualified or is a reference type then the<br>
// trait is false. Otherwise if __is_pod (type) is true then the<br>
@@ -4624,6 +4634,8 @@ static bool EvaluateUnaryTypeTrait(Sema<br>
return true;<br>
<br>
case UTT_HasTrivialDestructor:<br>
+ if (T.isDestructedType() == QualType::DK_nontrivial_c_<wbr>struct)<br>
+ return false;<br>
// <a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html" rel="noreferrer" target="_blank">http://gcc.gnu.org/onlinedocs/<wbr>gcc/Type-Traits.html</a><br>
// If __is_pod (type) is true or type is a reference type<br>
// then the trait is true, else if type is a cv class or union<br>
<br>
Added: cfe/trunk/test/SemaObjC/non-<wbr>trivial-struct-traits.m<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/non-trivial-struct-traits.m?rev=328680&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/cfe/trunk/test/<wbr>SemaObjC/non-trivial-struct-<wbr>traits.m?rev=328680&view=auto</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- cfe/trunk/test/SemaObjC/non-<wbr>trivial-struct-traits.m (added)<br>
+++ cfe/trunk/test/SemaObjC/non-<wbr>trivial-struct-traits.m Tue Mar 27 17:12:08 2018<br>
@@ -0,0 +1,25 @@<br>
+// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -verify %s<br>
+<br>
+// expected-no-diagnostics<br>
+<br>
+struct Trivial {<br>
+ int x;<br>
+};<br>
+<br>
+struct NonTrivial {<br>
+ id x;<br>
+};<br>
+<br>
+int trivial_assign[__has_trivial_<wbr>assign(struct Trivial) ? 1 : -1];<br>
+int trivial_move_assign[__has_<wbr>trivial_move_assign(struct Trivial) ? 1 : -1];<br>
+int trivial_copy_constructor[__<wbr>has_trivial_copy(struct Trivial) ? 1 : -1];<br>
+int trivial_move_constructor[__<wbr>has_trivial_move_constructor(<wbr>struct Trivial) ? 1 : -1];<br>
+int trivial_constructor[__has_<wbr>trivial_constructor(struct Trivial) ? 1 : -1];<br>
+int trivial_destructor[__has_<wbr>trivial_destructor(struct Trivial) ? 1 : -1];<br>
+<br>
+int non_trivial_assign[__has_<wbr>trivial_assign(struct NonTrivial) ? -1 : 1];<br>
+int non_trivial_move_assign[__has_<wbr>trivial_move_assign(struct NonTrivial) ? -1 : 1];<br>
+int non_trivial_copy_constructor[_<wbr>_has_trivial_copy(struct NonTrivial) ? -1 : 1];<br>
+int non_trivial_move_constructor[_<wbr>_has_trivial_move_constructor(<wbr>struct NonTrivial) ? -1 : 1];<br>
+int non_trivial_constructor[__has_<wbr>trivial_constructor(struct NonTrivial) ? -1 : 1];<br>
+int non_trivial_destructor[__has_<wbr>trivial_destructor(struct NonTrivial) ? -1 : 1];<br>
<br>
<br>
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</blockquote></div><br></div></div>