https://github.com/philnik777 created
https://github.com/llvm/llvm-project/pull/93113
This changes `__is_trivially_equality_comparable` to do overload resolution
instead, which fixes a couple of false-positives (and a false-negative as a
drive-by).
Fixes #89293
>From 53b52a07f8720db4495b93099d3e1874453f6950 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklau...@berlin.de>
Date: Thu, 23 May 2024 01:48:06 +0200
Subject: [PATCH] [Clang] Fix __is_trivially_equality_comparable returning true
with ineligebile defaulted overloads
---
clang/include/clang/AST/Type.h | 3 --
clang/lib/AST/Type.cpp | 60 -------------------------
clang/lib/Sema/SemaExprCXX.cpp | 71 +++++++++++++++++++++++++++++-
clang/test/SemaCXX/type-traits.cpp | 28 ++++++++++++
4 files changed, 98 insertions(+), 64 deletions(-)
diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
index 9a5c6e8d562c3..628c7a0d2df83 100644
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -1126,9 +1126,6 @@ class QualType {
/// Return true if this is a trivially relocatable type.
bool isTriviallyRelocatableType(const ASTContext &Context) const;
- /// Return true if this is a trivially equality comparable type.
- bool isTriviallyEqualityComparableType(const ASTContext &Context) const;
-
/// Returns true if it is a class and it might be dynamic.
bool mayBeDynamicClass() const;
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 3b90b8229dd18..62ca402460f94 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -2768,66 +2768,6 @@ bool QualType::isTriviallyRelocatableType(const
ASTContext &Context) const {
}
}
-static bool
-HasNonDeletedDefaultedEqualityComparison(const CXXRecordDecl *Decl) {
- if (Decl->isUnion())
- return false;
- if (Decl->isLambda())
- return Decl->isCapturelessLambda();
-
- auto IsDefaultedOperatorEqualEqual = [&](const FunctionDecl *Function) {
- return Function->getOverloadedOperator() ==
- OverloadedOperatorKind::OO_EqualEqual &&
- Function->isDefaulted() && Function->getNumParams() > 0 &&
- (Function->getParamDecl(0)->getType()->isReferenceType() ||
- Decl->isTriviallyCopyable());
- };
-
- if (llvm::none_of(Decl->methods(), IsDefaultedOperatorEqualEqual) &&
- llvm::none_of(Decl->friends(), [&](const FriendDecl *Friend) {
- if (NamedDecl *ND = Friend->getFriendDecl()) {
- return ND->isFunctionOrFunctionTemplate() &&
- IsDefaultedOperatorEqualEqual(ND->getAsFunction());
- }
- return false;
- }))
- return false;
-
- return llvm::all_of(Decl->bases(),
- [](const CXXBaseSpecifier &BS) {
- if (const auto *RD =
BS.getType()->getAsCXXRecordDecl())
- return HasNonDeletedDefaultedEqualityComparison(RD);
- return true;
- }) &&
- llvm::all_of(Decl->fields(), [](const FieldDecl *FD) {
- auto Type = FD->getType();
- if (Type->isArrayType())
- Type =
Type->getBaseElementTypeUnsafe()->getCanonicalTypeUnqualified();
-
- if (Type->isReferenceType() || Type->isEnumeralType())
- return false;
- if (const auto *RD = Type->getAsCXXRecordDecl())
- return HasNonDeletedDefaultedEqualityComparison(RD);
- return true;
- });
-}
-
-bool QualType::isTriviallyEqualityComparableType(
- const ASTContext &Context) const {
- QualType CanonicalType = getCanonicalType();
- if (CanonicalType->isIncompleteType() || CanonicalType->isDependentType() ||
- CanonicalType->isEnumeralType() || CanonicalType->isArrayType())
- return false;
-
- if (const auto *RD = CanonicalType->getAsCXXRecordDecl()) {
- if (!HasNonDeletedDefaultedEqualityComparison(RD))
- return false;
- }
-
- return Context.hasUniqueObjectRepresentations(
- CanonicalType, /*CheckIfTriviallyCopyable=*/false);
-}
-
bool QualType::isNonWeakInMRRWithObjCWeak(const ASTContext &Context) const {
return !Context.getLangOpts().ObjCAutoRefCount &&
Context.getLangOpts().ObjCWeak &&
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index f543e006060d6..ccf678e666ecb 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -5199,6 +5199,75 @@ static bool HasNoThrowOperator(const RecordType *RT,
OverloadedOperatorKind Op,
return false;
}
+static bool
+HasNonDeletedDefaultedEqualityComparison(Sema& S, const CXXRecordDecl *Decl) {
+ if (Decl->isUnion())
+ return false;
+ if (Decl->isLambda())
+ return Decl->isCapturelessLambda();
+
+ {
+ EnterExpressionEvaluationContext UnevaluatedContext(
+ S, Sema::ExpressionEvaluationContext::Unevaluated);
+ Sema::SFINAETrap SFINAE(S, /*AccessCheckingSFINAE=*/true);
+ Sema::ContextRAII TUContext(S, S.Context.getTranslationUnitDecl());
+
+ // const ClassT& obj;
+ OpaqueValueExpr Operand(
+ {}, Decl->getTypeForDecl()->getCanonicalTypeUnqualified().withConst(),
+ ExprValueKind::VK_LValue);
+ UnresolvedSet<16> Functions;
+ // obj == obj;
+ S.LookupBinOp(S.TUScope, {}, BinaryOperatorKind::BO_EQ, Functions);
+
+ auto Result = S.CreateOverloadedBinOp({}, BinaryOperatorKind::BO_EQ,
+ Functions, &Operand, &Operand);
+ if (Result.isInvalid() || SFINAE.hasErrorOccurred())
+ return false;
+ auto Callee = Result.getAs<CXXOperatorCallExpr>()->getDirectCallee();
+ auto ParamT = Callee->getParamDecl(0)->getType();
+ if (!Callee->isDefaulted() ||
+ (!ParamT->isReferenceType() && !Decl->isTriviallyCopyable()))
+ return false;
+ }
+
+ return llvm::all_of(Decl->bases(),
+ [&](const CXXBaseSpecifier &BS) {
+ if (const auto *RD =
BS.getType()->getAsCXXRecordDecl())
+ return HasNonDeletedDefaultedEqualityComparison(S,
+ RD);
+ return true;
+ }) &&
+ llvm::all_of(Decl->fields(), [&](const FieldDecl *FD) {
+ auto Type = FD->getType();
+ if (Type->isArrayType())
+ Type = Type->getBaseElementTypeUnsafe()
+ ->getCanonicalTypeUnqualified();
+
+ if (Type->isReferenceType() || Type->isEnumeralType())
+ return false;
+ if (const auto *RD = Type->getAsCXXRecordDecl())
+ return HasNonDeletedDefaultedEqualityComparison(S, RD);
+ return true;
+ });
+}
+
+static bool isTriviallyEqualityComparableType(
+ Sema& S, QualType Type) {
+ QualType CanonicalType = Type.getCanonicalType();
+ if (CanonicalType->isIncompleteType() || CanonicalType->isDependentType() ||
+ CanonicalType->isEnumeralType() || CanonicalType->isArrayType())
+ return false;
+
+ if (const auto *RD = CanonicalType->getAsCXXRecordDecl()) {
+ if (!HasNonDeletedDefaultedEqualityComparison(S, RD))
+ return false;
+ }
+
+ return S.getASTContext().hasUniqueObjectRepresentations(
+ CanonicalType, /*CheckIfTriviallyCopyable=*/false);
+}
+
static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
SourceLocation KeyLoc,
TypeSourceInfo *TInfo) {
@@ -5629,7 +5698,7 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait
UTT,
Self.Diag(KeyLoc, diag::err_builtin_pass_in_regs_non_class) << T;
return false;
case UTT_IsTriviallyEqualityComparable:
- return T.isTriviallyEqualityComparableType(C);
+ return isTriviallyEqualityComparableType(Self, T);
}
}
diff --git a/clang/test/SemaCXX/type-traits.cpp
b/clang/test/SemaCXX/type-traits.cpp
index d40605f56f1ed..d06495e9cfb66 100644
--- a/clang/test/SemaCXX/type-traits.cpp
+++ b/clang/test/SemaCXX/type-traits.cpp
@@ -3885,8 +3885,36 @@ struct
NotTriviallyEqualityComparableNonTriviallyEqualityComparableArrs2 {
bool operator==(const
NotTriviallyEqualityComparableNonTriviallyEqualityComparableArrs2&) const =
default;
};
+
static_assert(!__is_trivially_equality_comparable(NotTriviallyEqualityComparableNonTriviallyEqualityComparableArrs2));
+template<bool B>
+struct MaybeTriviallyEqualityComparable {
+ int i;
+ bool operator==(const MaybeTriviallyEqualityComparable&) const requires B
= default;
+ bool operator==(const MaybeTriviallyEqualityComparable& rhs) const {
return (i % 3) == (rhs.i % 3); }
+};
+static_assert(__is_trivially_equality_comparable(MaybeTriviallyEqualityComparable<true>));
+static_assert(!__is_trivially_equality_comparable(MaybeTriviallyEqualityComparable<false>));
+
+struct NotTriviallyEqualityComparableMoreConstrainedExternalOp {
+ int i;
+ bool operator==(const
NotTriviallyEqualityComparableMoreConstrainedExternalOp&) const = default;
+};
+
+bool operator==(const NotTriviallyEqualityComparableMoreConstrainedExternalOp&,
+ const
NotTriviallyEqualityComparableMoreConstrainedExternalOp&)
__attribute__((enable_if(true, ""))) {}
+
+static_assert(!__is_trivially_equality_comparable(NotTriviallyEqualityComparableMoreConstrainedExternalOp));
+
+struct TriviallyEqualityComparableExternalDefaultedOp {
+ int i;
+ friend bool operator==(TriviallyEqualityComparableExternalDefaultedOp,
TriviallyEqualityComparableExternalDefaultedOp);
+};
+bool operator==(TriviallyEqualityComparableExternalDefaultedOp,
TriviallyEqualityComparableExternalDefaultedOp) = default;
+
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableExternalDefaultedOp));
+
namespace hidden_friend {
struct TriviallyEqualityComparable {
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