mizvekov created this revision.
mizvekov requested review of this revision.
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Word on the grapevine is that the committee recently had an unanimous
vote on eliminating relational function pointer comparisons.
There isn't any wording on it or anything, yet, but we must jump the gun here
and just do away with it pronto.
Signed-off-by: Matheus Izvekov <mizve...@gmail.com>
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D104680
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaDeclCXX.cpp
clang/lib/Sema/SemaExpr.cpp
clang/lib/Sema/SemaOverload.cpp
clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
clang/test/CXX/drs/dr15xx.cpp
clang/test/CXX/drs/dr3xx.cpp
clang/test/CXX/expr/expr.const/p2-0x.cpp
clang/test/SemaCXX/compare-cxx2a.cpp
clang/test/SemaCXX/compare-function-pointer.cpp
Index: clang/test/SemaCXX/compare-function-pointer.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/compare-function-pointer.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify %s
+
+using fp_t = void (*)();
+extern fp_t a, b;
+
+bool eq = a == b;
+bool ne = a != b;
+bool lt = a < b; // expected-error {{ordered comparison of function pointers ('fp_t' (aka 'void (*)()') and 'fp_t')}}
+bool le = a <= b; // expected-error {{ordered comparison of function pointers}}
+bool gt = a > b; // expected-error {{ordered comparison of function pointers}}
+bool ge = a >= b; // expected-error {{ordered comparison of function pointers}}
+bool tw = a <=> b; // expected-error {{ordered comparison of function pointers}}
Index: clang/test/SemaCXX/compare-cxx2a.cpp
===================================================================
--- clang/test/SemaCXX/compare-cxx2a.cpp
+++ clang/test/SemaCXX/compare-cxx2a.cpp
@@ -212,8 +212,6 @@
struct ClassB : Class {};
struct Class2 {};
using FnTy = void(int);
-using FnTy2 = long(int);
-using FnTy3 = void(int) noexcept;
using MemFnTy = void (Class::*)() const;
using MemDataTy = long(Class::*);
@@ -232,11 +230,6 @@
(void)(md <=> md); // expected-error {{invalid operands}} expected-warning {{self-comparison}}
}
-void test_compatible_pointer(FnTy *f1, FnTy2 *f2, FnTy3 *f3) {
- (void)(f1 <=> f2); // expected-error {{distinct pointer types}}
- (void)(f1 <=> f3); // expected-error {{invalid operands}}
-}
-
// Test that variable narrowing is deferred for value dependent expressions
template <int Val>
auto test_template_overflow() {
Index: clang/test/CXX/expr/expr.const/p2-0x.cpp
===================================================================
--- clang/test/CXX/expr/expr.const/p2-0x.cpp
+++ clang/test/CXX/expr/expr.const/p2-0x.cpp
@@ -514,8 +514,7 @@
void f(), g();
constexpr void (*pf)() = &f, (*pg)() = &g;
- constexpr bool u13 = pf < pg; // expected-error {{constant expression}} expected-note {{comparison has unspecified value}}
- constexpr bool u14 = pf == pg;
+ constexpr bool u13 = pf == pg;
// If two pointers point to non-static data members of the same object with
// different access control, the result is unspecified.
Index: clang/test/CXX/drs/dr3xx.cpp
===================================================================
--- clang/test/CXX/drs/dr3xx.cpp
+++ clang/test/CXX/drs/dr3xx.cpp
@@ -18,9 +18,9 @@
void operator-(S, S);
void f() {
- bool a = (void(*)(S, S))operator+<S> <
+ bool a = (void(*)(S, S))operator+<S> < // expected-error {{ordered comparison of function pointers}}
(void(*)(S, S))operator+<S>;
- bool b = (void(*)(S, S))operator- < // cxx20_2b-note {{to match this '<'}}
+ bool b = (void(*)(S, S))operator- < // cxx20_2b-note {{to match this '<'}} cxx98_17-error {{ordered comparison of function pointers}}
(void(*)(S, S))operator-; // cxx20_2b-error {{expected '>'}}
bool c = (void(*)(S, S))operator+ < // expected-note {{to match this '<'}}
(void(*)(S, S))operator-; // expected-error {{expected '>'}}
Index: clang/test/CXX/drs/dr15xx.cpp
===================================================================
--- clang/test/CXX/drs/dr15xx.cpp
+++ clang/test/CXX/drs/dr15xx.cpp
@@ -79,8 +79,8 @@
no_composite_pointer_type<const int (A::*)(), volatile int (C::*)()>();
#if __cplusplus > 201402
- composite_pointer_type_is_ord<int (*)() noexcept, int (*)(), int (*)()>();
- composite_pointer_type_is_ord<int (*)(), int (*)() noexcept, int (*)()>();
+ composite_pointer_type_is_unord<int (*)() noexcept, int (*)(), int (*)()>();
+ composite_pointer_type_is_unord<int (*)(), int (*)() noexcept, int (*)()>();
composite_pointer_type_is_unord<int (A::*)() noexcept, int (A::*)(), int (A::*)()>();
composite_pointer_type_is_unord<int (A::*)(), int (A::*)() noexcept, int (A::*)()>();
// FIXME: This looks like a standard defect; these should probably all have type 'int (B::*)()'.
Index: clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
===================================================================
--- clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
+++ clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
@@ -159,7 +159,7 @@
namespace PR48856 {
struct A {
auto operator<=>(const A &) const = default; // expected-warning {{implicitly deleted}}
- void (*x)(); // expected-note {{does not support relational comparisons}}
+ void (*x)(); // expected-note {{because there is no viable three-way comparison function for member 'x'}}
};
struct B {
@@ -198,6 +198,6 @@
};
struct b3 {
auto operator<=>(b3 const &) const = default; // expected-warning {{implicitly deleted}}
- a3 f; // expected-note {{would compare member 'f' as 'void (*)()', which does not support relational comparisons}}
+ a3 f; // expected-note {{because there is no viable three-way comparison function for member 'f'}}
};
}
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -8466,7 +8466,7 @@
// bool operator==(T, T);
// bool operator!=(T, T);
// R operator<=>(T, T)
- void addGenericBinaryPointerOrEnumeralOverloads() {
+ void addGenericBinaryPointerOrEnumeralOverloads(bool IsOrdered) {
// C++ [over.match.oper]p3:
// [...]the built-in candidates include all of the candidate operator
// functions defined in 13.6 that, compared to the given operator, [...]
@@ -8525,6 +8525,8 @@
// Don't add the same builtin candidate twice.
if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
continue;
+ if (IsOrdered && PtrTy->isFunctionPointerType())
+ continue;
QualType ParamTypes[2] = {PtrTy, PtrTy};
S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
@@ -8715,7 +8717,7 @@
//
// where LR is the result of the usual arithmetic conversions
// between types L and R.
- void addBinaryBitwiseArithmeticOverloads(OverloadedOperatorKind Op) {
+ void addBinaryBitwiseArithmeticOverloads() {
if (!HasArithmeticOrEnumeralCandidateType)
return;
@@ -9221,18 +9223,20 @@
case OO_EqualEqual:
case OO_ExclaimEqual:
OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads();
- LLVM_FALLTHROUGH;
+ OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(false);
+ OpBuilder.addGenericBinaryArithmeticOverloads();
+ break;
case OO_Less:
case OO_Greater:
case OO_LessEqual:
case OO_GreaterEqual:
- OpBuilder.addGenericBinaryPointerOrEnumeralOverloads();
+ OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(true);
OpBuilder.addGenericBinaryArithmeticOverloads();
break;
case OO_Spaceship:
- OpBuilder.addGenericBinaryPointerOrEnumeralOverloads();
+ OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(true);
OpBuilder.addThreeWayArithmeticOverloads();
break;
@@ -9241,7 +9245,7 @@
case OO_Pipe:
case OO_LessLess:
case OO_GreaterGreater:
- OpBuilder.addBinaryBitwiseArithmeticOverloads(Op);
+ OpBuilder.addBinaryBitwiseArithmeticOverloads();
break;
case OO_Amp: // '&' is either unary or binary
@@ -9251,7 +9255,7 @@
// operator '->', the built-in candidates set is empty.
break;
- OpBuilder.addBinaryBitwiseArithmeticOverloads(Op);
+ OpBuilder.addBinaryBitwiseArithmeticOverloads();
break;
case OO_Tilde:
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -11802,6 +11802,19 @@
LHS.get()->getSourceRange());
}
+ if (IsOrdered && LHSType->isFunctionPointerType() &&
+ RHSType->isFunctionPointerType()) {
+ // Valid unless a relational comparison of function pointers
+ bool IsError = getLangOpts().CPlusPlus;
+ Diag(Loc, IsError
+ ? diag::err_typecheck_ordered_comparison_of_function_pointers
+ : diag::ext_typecheck_ordered_comparison_of_function_pointers)
+ << LHSType << RHSType << LHS.get()->getSourceRange()
+ << RHS.get()->getSourceRange();
+ if (IsError)
+ return QualType();
+ }
+
if ((LHSType->isIntegerType() && !LHSIsNull) ||
(RHSType->isIntegerType() && !RHSIsNull)) {
// Skip normal pointer conversion checks in this case; we have better
@@ -11869,12 +11882,6 @@
<< LHSType << RHSType << LCanPointeeTy->isIncompleteType()
<< RCanPointeeTy->isIncompleteType();
}
- if (LCanPointeeTy->isFunctionType()) {
- // Valid unless a relational comparison of function pointers
- Diag(Loc, diag::ext_typecheck_ordered_comparison_of_function_pointers)
- << LHSType << RHSType << LHS.get()->getSourceRange()
- << RHS.get()->getSourceRange();
- }
}
} else if (!IsRelational &&
(LCanPointeeTy->isVoidType() || RCanPointeeTy->isVoidType())) {
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -7866,15 +7866,6 @@
assert(Best->BuiltinParamTypes[2].isNull() &&
"invalid builtin comparison");
- // The builtin operator for relational comparisons on function
- // pointers is the only known case which cannot be used.
- if (OO != OO_EqualEqual && T->isFunctionPointerType()) {
- if (Diagnose == ExplainDeleted)
- S.Diag(Subobj.Loc, diag::note_defaulted_comparison_selected_invalid)
- << Subobj.Kind << Subobj.Decl << T;
- return Result::deleted();
- }
-
if (NeedsDeducing) {
Optional<ComparisonCategoryType> Cat =
getComparisonCategoryForBuiltinCmp(T);
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6797,6 +6797,8 @@
def ext_typecheck_ordered_comparison_of_function_pointers : ExtWarn<
"ordered comparison of function pointers (%0 and %1)">,
InGroup<DiagGroup<"ordered-compare-function-pointers">>;
+def err_typecheck_ordered_comparison_of_function_pointers : Error<
+ "ordered comparison of function pointers (%0 and %1)">;
def ext_typecheck_comparison_of_fptr_to_void : Extension<
"equality comparison between function pointer and void pointer (%0 and %1)">;
def err_typecheck_comparison_of_fptr_to_void : Error<
@@ -9143,9 +9145,6 @@
"%select{|member|base class}0 %1 declared here">;
def note_defaulted_comparison_cannot_deduce_callee : Note<
"selected 'operator<=>' for %select{|member|base class}0 %1 declared here">;
-def note_defaulted_comparison_selected_invalid : Note<
- "would compare %select{|member|base class}0 %1 "
- "as %2, which does not support relational comparisons">;
def err_incorrect_defaulted_comparison_constexpr : Error<
"defaulted definition of %select{%sub{select_defaulted_comparison_kind}1|"
"three-way comparison operator}0 "
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