https://github.com/bgra8 created https://github.com/llvm/llvm-project/pull/94600
Reverting due to https://github.com/llvm/llvm-project/pull/92527#issuecomment-2149120420. This reverts commit f049d72ac2bcc40fd91d4e95148658021fb24bf1. >From fbaa1ce73030c456c62ab8b2d002b8f04b6913a7 Mon Sep 17 00:00:00 2001 From: Bogdan Graur <bgr...@google.com> Date: Thu, 6 Jun 2024 09:48:36 +0000 Subject: [PATCH] Revert "Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#92527)" Reverting due to https://github.com/llvm/llvm-project/pull/92527#issuecomment-2149120420. This reverts commit f049d72ac2bcc40fd91d4e95148658021fb24bf1. --- .../clang/Basic/DiagnosticSemaKinds.td | 6 ++ clang/lib/Sema/SemaExpr.cpp | 31 ++------ clang/lib/Sema/SemaExprCXX.cpp | 3 + clang/lib/Sema/SemaInit.cpp | 19 ++++- clang/lib/Sema/TreeTransform.h | 12 +-- clang/test/AST/ast-dump-default-init-json.cpp | 6 +- clang/test/AST/ast-dump-default-init.cpp | 2 +- .../Analysis/lifetime-extended-regions.cpp | 9 +-- clang/test/CXX/drs/cwg16xx.cpp | 2 + clang/test/CXX/drs/cwg18xx.cpp | 19 ++--- clang/test/CXX/special/class.temporary/p6.cpp | 34 --------- clang/test/SemaCXX/constexpr-default-arg.cpp | 4 +- .../cxx11-default-member-initializers.cpp | 74 ------------------- clang/test/SemaCXX/eval-crashes.cpp | 6 +- clang/www/cxx_dr_status.html | 2 +- 15 files changed, 61 insertions(+), 168 deletions(-) diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 87745140cb0eb..9f0b6f5a36389 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -10082,6 +10082,12 @@ def warn_new_dangling_initializer_list : Warning< "the allocated initializer list}0 " "will be destroyed at the end of the full-expression">, InGroup<DanglingInitializerList>; +def warn_unsupported_lifetime_extension : Warning< + "lifetime extension of " + "%select{temporary|backing array of initializer list}0 created " + "by aggregate initialization using a default member initializer " + "is not yet supported; lifetime of %select{temporary|backing array}0 " + "will end at the end of the full-expression">, InGroup<Dangling>; // For non-floating point, expressions of the form x == x or x != x // should result in a warning, since these always evaluate to a constant. diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index d8c77e3e0a5cd..76145f291887c 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -5572,9 +5572,10 @@ ExprResult Sema::BuildCXXDefaultArgExpr(SourceLocation CallLoc, Res = Immediate.TransformInitializer(Param->getInit(), /*NotCopy=*/false); }); - if (Res.isUsable()) - Res = ConvertParamDefaultArgument(Param, Res.get(), - Res.get()->getBeginLoc()); + if (Res.isInvalid()) + return ExprError(); + Res = ConvertParamDefaultArgument(Param, Res.get(), + Res.get()->getBeginLoc()); if (Res.isInvalid()) return ExprError(); Init = Res.get(); @@ -5610,7 +5611,7 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field) { Expr *Init = nullptr; bool NestedDefaultChecking = isCheckingDefaultArgumentOrInitializer(); - bool InLifetimeExtendingContext = isInLifetimeExtendingContext(); + EnterExpressionEvaluationContext EvalContext( *this, ExpressionEvaluationContext::PotentiallyEvaluated, Field); @@ -5645,35 +5646,19 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field) { ImmediateCallVisitor V(getASTContext()); if (!NestedDefaultChecking) V.TraverseDecl(Field); - - // CWG1815 - // Support lifetime extension of temporary created by aggregate - // initialization using a default member initializer. We should always rebuild - // the initializer if it contains any temporaries (if the initializer - // expression is an ExprWithCleanups). Then make sure the normal lifetime - // extension code recurses into the default initializer and does lifetime - // extension when warranted. - bool ContainsAnyTemporaries = - isa_and_present<ExprWithCleanups>(Field->getInClassInitializer()); - if (V.HasImmediateCalls || InLifetimeExtendingContext || - ContainsAnyTemporaries) { + if (V.HasImmediateCalls) { ExprEvalContexts.back().DelayedDefaultInitializationContext = {Loc, Field, CurContext}; ExprEvalContexts.back().IsCurrentlyCheckingDefaultArgumentOrInitializer = NestedDefaultChecking; - // Pass down lifetime extending flag, and collect temporaries in - // CreateMaterializeTemporaryExpr when we rewrite the call argument. - keepInLifetimeExtendingContext(); + EnsureImmediateInvocationInDefaultArgs Immediate(*this); ExprResult Res; - - // Rebuild CXXDefaultInitExpr might cause diagnostics. - SFINAETrap Trap(*this); runWithSufficientStackSpace(Loc, [&] { Res = Immediate.TransformInitializer(Field->getInClassInitializer(), /*CXXDirectInit=*/false); }); - if (Res.isUsable()) + if (!Res.isInvalid()) Res = ConvertMemberDefaultInitExpression(Field, Res.get(), Loc); if (Res.isInvalid()) { Field->setInvalidDecl(); diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp index eb0d987f63da5..cf461a68d5526 100644 --- a/clang/lib/Sema/SemaExprCXX.cpp +++ b/clang/lib/Sema/SemaExprCXX.cpp @@ -1555,6 +1555,9 @@ Sema::BuildCXXTypeConstructExpr(TypeSourceInfo *TInfo, bool ListInitialization) { QualType Ty = TInfo->getType(); SourceLocation TyBeginLoc = TInfo->getTypeLoc().getBeginLoc(); + + assert((!ListInitialization || Exprs.size() == 1) && + "List initialization must have exactly one expression."); SourceRange FullRange = SourceRange(TyBeginLoc, RParenOrBraceLoc); InitializedEntity Entity = diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp index 9ed3e8a0df025..ed8b226a6b39f 100644 --- a/clang/lib/Sema/SemaInit.cpp +++ b/clang/lib/Sema/SemaInit.cpp @@ -8063,6 +8063,11 @@ static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path, enum PathLifetimeKind { /// Lifetime-extend along this path. Extend, + /// We should lifetime-extend, but we don't because (due to technical + /// limitations) we can't. This happens for default member initializers, + /// which we don't clone for every use, so we don't have a unique + /// MaterializeTemporaryExpr to update. + ShouldExtend, /// Do not lifetime extend along this path. NoExtend }; @@ -8074,7 +8079,7 @@ shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) { PathLifetimeKind Kind = PathLifetimeKind::Extend; for (auto Elem : Path) { if (Elem.Kind == IndirectLocalPathEntry::DefaultInit) - Kind = PathLifetimeKind::Extend; + Kind = PathLifetimeKind::ShouldExtend; else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit) return PathLifetimeKind::NoExtend; } @@ -8194,6 +8199,18 @@ void Sema::checkInitializerLifetime(const InitializedEntity &Entity, ExtendingEntity->allocateManglingNumber()); // Also visit the temporaries lifetime-extended by this initializer. return true; + + case PathLifetimeKind::ShouldExtend: + // We're supposed to lifetime-extend the temporary along this path (per + // the resolution of DR1815), but we don't support that yet. + // + // FIXME: Properly handle this situation. Perhaps the easiest approach + // would be to clone the initializer expression on each use that would + // lifetime extend its temporaries. + Diag(DiagLoc, diag::warn_unsupported_lifetime_extension) + << RK << DiagRange; + break; + case PathLifetimeKind::NoExtend: // If the path goes through the initialization of a variable or field, // it can't possibly reach a temporary created in this full-expression. diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h index 95dd356d48bed..3bfda09d5f80f 100644 --- a/clang/lib/Sema/TreeTransform.h +++ b/clang/lib/Sema/TreeTransform.h @@ -14172,13 +14172,6 @@ TreeTransform<Derived>::TransformCXXTemporaryObjectExpr( if (TransformExprs(E->getArgs(), E->getNumArgs(), true, Args, &ArgumentChanged)) return ExprError(); - - if (E->isListInitialization() && !E->isStdInitListInitialization()) { - ExprResult Res = RebuildInitList(E->getBeginLoc(), Args, E->getEndLoc()); - if (Res.isInvalid()) - return ExprError(); - Args = {Res.get()}; - } } if (!getDerived().AlwaysRebuild() && @@ -14190,9 +14183,12 @@ TreeTransform<Derived>::TransformCXXTemporaryObjectExpr( return SemaRef.MaybeBindToTemporary(E); } + // FIXME: We should just pass E->isListInitialization(), but we're not + // prepared to handle list-initialization without a child InitListExpr. SourceLocation LParenLoc = T->getTypeLoc().getEndLoc(); return getDerived().RebuildCXXTemporaryObjectExpr( - T, LParenLoc, Args, E->getEndLoc(), E->isListInitialization()); + T, LParenLoc, Args, E->getEndLoc(), + /*ListInitialization=*/LParenLoc.isInvalid()); } template<typename Derived> diff --git a/clang/test/AST/ast-dump-default-init-json.cpp b/clang/test/AST/ast-dump-default-init-json.cpp index f4949a9c9eedf..1058b4e3ea4d9 100644 --- a/clang/test/AST/ast-dump-default-init-json.cpp +++ b/clang/test/AST/ast-dump-default-init-json.cpp @@ -789,10 +789,10 @@ void test() { // CHECK-NEXT: "valueCategory": "lvalue", // CHECK-NEXT: "extendingDecl": { // CHECK-NEXT: "id": "0x{{.*}}", -// CHECK-NEXT: "kind": "VarDecl", -// CHECK-NEXT: "name": "b", +// CHECK-NEXT: "kind": "FieldDecl", +// CHECK-NEXT: "name": "a", // CHECK-NEXT: "type": { -// CHECK-NEXT: "qualType": "B" +// CHECK-NEXT: "qualType": "const A &" // CHECK-NEXT: } // CHECK-NEXT: }, // CHECK-NEXT: "storageDuration": "automatic", diff --git a/clang/test/AST/ast-dump-default-init.cpp b/clang/test/AST/ast-dump-default-init.cpp index 26864fbf15424..15b29f04bf21b 100644 --- a/clang/test/AST/ast-dump-default-init.cpp +++ b/clang/test/AST/ast-dump-default-init.cpp @@ -13,7 +13,7 @@ void test() { } // CHECK: -CXXDefaultInitExpr 0x{{[^ ]*}} <{{.*}}> 'const A' lvalue has rewritten init // CHECK-NEXT: `-ExprWithCleanups 0x{{[^ ]*}} <{{.*}}> 'const A' lvalue -// CHECK-NEXT: `-MaterializeTemporaryExpr 0x{{[^ ]*}} <{{.*}}> 'const A' lvalue extended by Var 0x{{[^ ]*}} 'b' 'B' +// CHECK-NEXT: `-MaterializeTemporaryExpr 0x{{[^ ]*}} <{{.*}}> 'const A' lvalue extended by Field 0x{{[^ ]*}} 'a' 'const A &' // CHECK-NEXT: `-ImplicitCastExpr 0x{{[^ ]*}} <{{.*}}> 'const A' <NoOp> // CHECK-NEXT: `-CXXFunctionalCastExpr 0x{{[^ ]*}} <{{.*}}> 'A' functional cast to A <NoOp> // CHECK-NEXT: `-InitListExpr 0x{{[^ ]*}} <{{.*}}> 'A' diff --git a/clang/test/Analysis/lifetime-extended-regions.cpp b/clang/test/Analysis/lifetime-extended-regions.cpp index 4458ad294af7c..4e98bd4b0403e 100644 --- a/clang/test/Analysis/lifetime-extended-regions.cpp +++ b/clang/test/Analysis/lifetime-extended-regions.cpp @@ -120,11 +120,10 @@ void aggregateWithReferences() { clang_analyzer_dump(viaReference); // expected-warning-re {{&lifetime_extended_object{RefAggregate, viaReference, S{{[0-9]+}}} }} clang_analyzer_dump(viaReference.rx); // expected-warning-re {{&lifetime_extended_object{int, viaReference, S{{[0-9]+}}} }} clang_analyzer_dump(viaReference.ry); // expected-warning-re {{&lifetime_extended_object{Composite, viaReference, S{{[0-9]+}}} }} - - // FIXME: clang currently support extending lifetime of object bound to reference members of aggregates, - // that are created from default member initializer. But CFG and ExprEngine need to be updated to address this change. - // The following expect warning: {{&lifetime_extended_object{Composite, defaultInitExtended, S{{[0-9]+}}} }} - RefAggregate defaultInitExtended{i}; + + // clang does not currently implement extending lifetime of object bound to reference members of aggregates, + // that are created from default member initializer (see `warn_unsupported_lifetime_extension` from `-Wdangling`) + RefAggregate defaultInitExtended{i}; // clang-bug does not extend `Composite` clang_analyzer_dump(defaultInitExtended.ry); // expected-warning {{Unknown }} } diff --git a/clang/test/CXX/drs/cwg16xx.cpp b/clang/test/CXX/drs/cwg16xx.cpp index 82ef871939d2c..cf6b45ceabf2c 100644 --- a/clang/test/CXX/drs/cwg16xx.cpp +++ b/clang/test/CXX/drs/cwg16xx.cpp @@ -483,6 +483,8 @@ namespace cwg1696 { // cwg1696: 7 const A &a = A(); // #cwg1696-D1-a }; D1 d1 = {}; // #cwg1696-d1 + // since-cxx14-warning@-1 {{lifetime extension of temporary created by aggregate initialization using a default member initializer is not yet supported; lifetime of temporary will end at the end of the full-expression}} + // since-cxx14-note@#cwg1696-D1-a {{initializing field 'a' with default member initializer}} struct D2 { const A &a = A(); // #cwg1696-D2-a diff --git a/clang/test/CXX/drs/cwg18xx.cpp b/clang/test/CXX/drs/cwg18xx.cpp index 054ce5a4f4b70..323e56f9c5278 100644 --- a/clang/test/CXX/drs/cwg18xx.cpp +++ b/clang/test/CXX/drs/cwg18xx.cpp @@ -206,28 +206,19 @@ namespace cwg1814 { // cwg1814: yes #endif } -namespace cwg1815 { // cwg1815: 19 +namespace cwg1815 { // cwg1815: no #if __cplusplus >= 201402L - struct A { int &&r = 0; }; + // FIXME: needs codegen test + struct A { int &&r = 0; }; // #cwg1815-A A a = {}; + // since-cxx14-warning@-1 {{lifetime extension of temporary created by aggregate initialization using a default member initializer is not yet supported; lifetime of temporary will end at the end of the full-expression}} FIXME + // since-cxx14-note@#cwg1815-A {{initializing field 'r' with default member initializer}} struct B { int &&r = 0; }; // #cwg1815-B // since-cxx14-error@-1 {{reference member 'r' binds to a temporary object whose lifetime would be shorter than the lifetime of the constructed object}} // since-cxx14-note@#cwg1815-B {{initializing field 'r' with default member initializer}} // since-cxx14-note@#cwg1815-b {{in implicit default constructor for 'cwg1815::B' first required here}} B b; // #cwg1815-b - -#if __cplusplus >= 201703L - struct C { const int &r = 0; }; - constexpr C c = {}; // OK, since cwg1815 - static_assert(c.r == 0); - - constexpr int f() { - A a = {}; // OK, since cwg1815 - return a.r; - } - static_assert(f() == 0); -#endif #endif } diff --git a/clang/test/CXX/special/class.temporary/p6.cpp b/clang/test/CXX/special/class.temporary/p6.cpp index a6d2adfd1fd2c..5554363cc69ab 100644 --- a/clang/test/CXX/special/class.temporary/p6.cpp +++ b/clang/test/CXX/special/class.temporary/p6.cpp @@ -269,40 +269,6 @@ void init_capture_init_list() { // CHECK: } } -void check_dr1815() { // dr1815: yes -#if __cplusplus >= 201402L - - struct A { - int &&r = 0; - ~A() {} - }; - - struct B { - A &&a = A{}; - ~B() {} - }; - B a = {}; - - // CHECK: call {{.*}}block_scope_begin_function - extern void block_scope_begin_function(); - extern void block_scope_end_function(); - block_scope_begin_function(); - { - // CHECK: call void @_ZZ12check_dr1815vEN1BD1Ev - // CHECK: call void @_ZZ12check_dr1815vEN1AD1Ev - B b = {}; - } - // CHECK: call {{.*}}block_scope_end_function - block_scope_end_function(); - - // CHECK: call {{.*}}some_other_function - extern void some_other_function(); - some_other_function(); - // CHECK: call void @_ZZ12check_dr1815vEN1BD1Ev - // CHECK: call void @_ZZ12check_dr1815vEN1AD1Ev -#endif -} - namespace P2718R0 { namespace basic { template <typename E> using T2 = std::list<E>; diff --git a/clang/test/SemaCXX/constexpr-default-arg.cpp b/clang/test/SemaCXX/constexpr-default-arg.cpp index 901123bfb359f..ec9b2927880bd 100644 --- a/clang/test/SemaCXX/constexpr-default-arg.cpp +++ b/clang/test/SemaCXX/constexpr-default-arg.cpp @@ -32,8 +32,8 @@ void test_default_arg2() { } // Check that multiple CXXDefaultInitExprs don't cause an assertion failure. -struct A { int &&r = 0; }; +struct A { int &&r = 0; }; // expected-note 2{{default member initializer}} struct B { A x, y; }; -B b = {}; // expected-no-diagnostics +B b = {}; // expected-warning 2{{lifetime extension of temporary created by aggregate initialization using a default member initializer is not yet supported}} } diff --git a/clang/test/SemaCXX/cxx11-default-member-initializers.cpp b/clang/test/SemaCXX/cxx11-default-member-initializers.cpp index 1ea8b98cd8636..dd8e9c6b7fc11 100644 --- a/clang/test/SemaCXX/cxx11-default-member-initializers.cpp +++ b/clang/test/SemaCXX/cxx11-default-member-initializers.cpp @@ -27,80 +27,6 @@ class MemInit { C m = s; }; -namespace std { -typedef decltype(sizeof(int)) size_t; - -// libc++'s implementation -template <class _E> class initializer_list { - const _E *__begin_; - size_t __size_; - - initializer_list(const _E *__b, size_t __s) : __begin_(__b), __size_(__s) {} - -public: - typedef _E value_type; - typedef const _E &reference; - typedef const _E &const_reference; - typedef size_t size_type; - - typedef const _E *iterator; - typedef const _E *const_iterator; - - initializer_list() : __begin_(nullptr), __size_(0) {} - - size_t size() const { return __size_; } - const _E *begin() const { return __begin_; } - const _E *end() const { return __begin_ + __size_; } -}; -} // namespace std - -#if __cplusplus >= 201703L -namespace test_rebuild { -template <typename T, int> class C { -public: - C(std::initializer_list<T>); -}; - -template <typename T> using Ptr = __remove_pointer(T) *; -template <typename T> C(T) -> C<Ptr<T>, sizeof(T)>; - -class A { -public: - template <typename T1, typename T2> T1 *some_func(T2 &&); -}; - -struct B : A { - // Test CXXDefaultInitExpr rebuild issue in - // https://github.com/llvm/llvm-project/pull/87933 - int *ar = some_func<int>(C{some_func<int>(0)}); - B() {} -}; - -int TestBody_got; -template <int> class Vector { -public: - Vector(std::initializer_list<int>); -}; -template <typename... Ts> Vector(Ts...) -> Vector<sizeof...(Ts)>; -class ProgramBuilder { -public: - template <typename T, typename ARGS> int *create(ARGS); -}; - -struct TypeTest : ProgramBuilder { - int *str_f16 = create<int>(Vector{0}); - TypeTest() {} -}; -class TypeTest_Element_Test : TypeTest { - void TestBody(); -}; -void TypeTest_Element_Test::TestBody() { - int *expect = str_f16; - &TestBody_got != expect; // expected-warning {{inequality comparison result unused}} -} -} // namespace test_rebuild -#endif // __cplusplus >= 201703L - #if __cplusplus >= 202002L // This test ensures cleanup expressions are correctly produced // in the presence of default member initializers. diff --git a/clang/test/SemaCXX/eval-crashes.cpp b/clang/test/SemaCXX/eval-crashes.cpp index a06f60f71e9c7..017df977b26b7 100644 --- a/clang/test/SemaCXX/eval-crashes.cpp +++ b/clang/test/SemaCXX/eval-crashes.cpp @@ -25,9 +25,11 @@ namespace pr33140_0b { } namespace pr33140_2 { - struct A { int &&r = 0; }; + // FIXME: The declaration of 'b' below should lifetime-extend two int + // temporaries. + struct A { int &&r = 0; }; // expected-note 2{{initializing field 'r' with default member initializer}} struct B { A x, y; }; - B b = {}; + B b = {}; // expected-warning 2{{lifetime extension of temporary created by aggregate initialization using a default member initializer is not yet supported}} } namespace pr33140_3 { diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html index b046468c85316..43857447d83b1 100755 --- a/clang/www/cxx_dr_status.html +++ b/clang/www/cxx_dr_status.html @@ -10698,7 +10698,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2> <td><a href="https://cplusplus.github.io/CWG/issues/1815.html";>1815</a></td> <td>CD4</td> <td>Lifetime extension in aggregate initialization</td> - <td class="unreleased" align="center">Clang 19</td> + <td class="none" align="center">No</td> </tr> <tr id="1816"> <td><a href="https://cplusplus.github.io/CWG/issues/1816.html";>1816</a></td> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
