Author: erichkeane Date: 2024-05-16T09:52:19-07:00 New Revision: 224116ab9f4d97acb0cca76dc63c1d3d4a253078
URL: https://github.com/llvm/llvm-project/commit/224116ab9f4d97acb0cca76dc63c1d3d4a253078 DIFF: https://github.com/llvm/llvm-project/commit/224116ab9f4d97acb0cca76dc63c1d3d4a253078.diff LOG: Revert "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer (#87933)" This reverts commit 17daa204feadf9c28fc13b7daa69c3cbe865b238. Multiple examples on the PR https://github.com/llvm/llvm-project/pull/87933 show regressions, so reverting until they can be fixed in the followup. Added: Modified: clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/SemaExpr.cpp clang/lib/Sema/SemaInit.cpp clang/test/AST/ast-dump-default-init-json.cpp clang/test/AST/ast-dump-default-init.cpp clang/test/Analysis/lifetime-extended-regions.cpp clang/test/CXX/drs/cwg16xx.cpp clang/test/CXX/drs/cwg18xx.cpp clang/test/CXX/special/class.temporary/p6.cpp clang/test/SemaCXX/constexpr-default-arg.cpp clang/test/SemaCXX/eval-crashes.cpp clang/www/cxx_dr_status.html Removed: ################################################################################ diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index e648b503ac034..3be9d34b36b06 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -10037,6 +10037,12 @@ 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 151cda5d68b01..274e1fb183534 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -5618,9 +5618,10 @@ 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(); @@ -5656,7 +5657,7 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field) { Expr *Init = nullptr; bool NestedDefaultChecking = isCheckingDefaultArgumentOrInitializer(); - bool InLifetimeExtendingContext = isInLifetimeExtendingContext(); + EnterExpressionEvaluationContext EvalContext( *this, ExpressionEvaluationContext::PotentiallyEvaluated, Field); @@ -5691,35 +5692,19 @@ 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/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp index 708286e192f9c..2177972f3af2c 100644 --- a/clang/lib/Sema/SemaInit.cpp +++ b/clang/lib/Sema/SemaInit.cpp @@ -8066,6 +8066,11 @@ 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 }; @@ -8077,7 +8082,7 @@ 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; } @@ -8197,6 +8202,18 @@ 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/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 89adc28384904..35615076a6288 100644 --- a/clang/test/CXX/drs/cwg18xx.cpp +++ b/clang/test/CXX/drs/cwg18xx.cpp @@ -56,7 +56,7 @@ namespace cwg1804 { // cwg1804: 2.7 template <typename, typename> struct A { void f1(); - + template <typename V> void f2(V); @@ -73,7 +73,7 @@ struct A { template <typename U> struct A<int, U> { void f1(); - + template <typename V> void f2(V); @@ -97,7 +97,7 @@ class D { template <typename U> struct A<double, U> { void f1(); - + template <typename V> void f2(V); @@ -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/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 abf5d4ae4676d..2ed79fa21db26 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
