https://github.com/yronglin updated
https://github.com/llvm/llvm-project/pull/97308
>From 9c4a7dae3ab2cb58708e39317a1c8f19b3709eb2 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Mon, 1 Jul 2024 23:20:58 +0800
Subject: [PATCH] Reapply "[Clang][CWG1815] Support lifetime extension of
temporary created by aggregate initialization using a default member
initializer"
Signed-off-by: yronglin <yronglin...@gmail.com>
---
.../clang/Basic/DiagnosticSemaKinds.td | 7 --
clang/lib/Sema/CheckExprLifetime.cpp | 18 +---
clang/lib/Sema/SemaExpr.cpp | 31 ++++--
clang/lib/Sema/SemaExprCXX.cpp | 3 -
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 | 95 +++++++++++++++++++
clang/test/SemaCXX/eval-crashes.cpp | 6 +-
clang/www/cxx_dr_status.html | 2 +-
15 files changed, 189 insertions(+), 61 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index d60f32674ca3a..32f693e2313af 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10138,13 +10138,6 @@ def warn_dangling_pointer_assignment : Warning<
"will be destroyed at the end of the full-expression">,
InGroup<DanglingAssignment>;
-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.
// Array comparisons have similar warnings
diff --git a/clang/lib/Sema/CheckExprLifetime.cpp
b/clang/lib/Sema/CheckExprLifetime.cpp
index d9031256f235f..a92ca4fb1575f 100644
--- a/clang/lib/Sema/CheckExprLifetime.cpp
+++ b/clang/lib/Sema/CheckExprLifetime.cpp
@@ -905,11 +905,6 @@ 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
};
@@ -921,7 +916,7 @@ shouldLifetimeExtendThroughPath(const IndirectLocalPath
&Path) {
PathLifetimeKind Kind = PathLifetimeKind::Extend;
for (auto Elem : Path) {
if (Elem.Kind == IndirectLocalPathEntry::DefaultInit)
- Kind = PathLifetimeKind::ShouldExtend;
+ return PathLifetimeKind::Extend;
else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit)
return PathLifetimeKind::NoExtend;
}
@@ -1053,17 +1048,6 @@ static void checkExprLifetimeImpl(Sema &SemaRef,
// 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.
- SemaRef.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/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 8d24e34520e77..1efb05499541d 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -5397,6 +5397,8 @@ struct EnsureImmediateInvocationInDefaultArgs
EnsureImmediateInvocationInDefaultArgs(Sema &SemaRef)
: TreeTransform(SemaRef) {}
+ bool AlwaysRebuild() { return true; }
+
// Lambda can only have immediate invocations in the default
// args of their parameters, which is transformed upon calling the closure.
// The body is not a subexpression, so we have nothing to do.
@@ -5474,10 +5476,9 @@ ExprResult Sema::BuildCXXDefaultArgExpr(SourceLocation
CallLoc,
Res = Immediate.TransformInitializer(Param->getInit(),
/*NotCopy=*/false);
});
- if (Res.isInvalid())
- return ExprError();
- Res = ConvertParamDefaultArgument(Param, Res.get(),
- Res.get()->getBeginLoc());
+ if (Res.isUsable())
+ Res = ConvertParamDefaultArgument(Param, Res.get(),
+ Res.get()->getBeginLoc());
if (Res.isInvalid())
return ExprError();
Init = Res.get();
@@ -5513,7 +5514,7 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
Expr *Init = nullptr;
bool NestedDefaultChecking = isCheckingDefaultArgumentOrInitializer();
-
+ bool InLifetimeExtendingContext = isInLifetimeExtendingContext();
EnterExpressionEvaluationContext EvalContext(
*this, ExpressionEvaluationContext::PotentiallyEvaluated, Field);
@@ -5548,19 +5549,33 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
ImmediateCallVisitor V(getASTContext());
if (!NestedDefaultChecking)
V.TraverseDecl(Field);
- if (V.HasImmediateCalls) {
+
+ // 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) {
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;
+ SFINAETrap Trap(*this);
runWithSufficientStackSpace(Loc, [&] {
Res = Immediate.TransformInitializer(Field->getInClassInitializer(),
/*CXXDirectInit=*/false);
});
- if (!Res.isInvalid())
+ if (Res.isUsable())
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 14d1f395af90e..7f8526b1bdcc9 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -1539,9 +1539,6 @@ 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/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 0f266171cb67a..a7388a0fea89e 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -14246,6 +14246,13 @@
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() &&
@@ -14257,12 +14264,9 @@
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(),
- /*ListInitialization=*/LParenLoc.isInvalid());
+ T, LParenLoc, Args, E->getEndLoc(), E->isListInitialization());
}
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 1058b4e3ea4d9..f4949a9c9eedf 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": "FieldDecl",
-// CHECK-NEXT: "name": "a",
+// CHECK-NEXT: "kind": "VarDecl",
+// CHECK-NEXT: "name": "b",
// CHECK-NEXT: "type": {
-// CHECK-NEXT: "qualType": "const A &"
+// CHECK-NEXT: "qualType": "B"
// 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 15b29f04bf21b..26864fbf15424 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 Field 0x{{[^ ]*}} 'a' 'const A &'
+// CHECK-NEXT: `-MaterializeTemporaryExpr 0x{{[^ ]*}} <{{.*}}> 'const A'
lvalue extended by Var 0x{{[^ ]*}} 'b' 'B'
// 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 4e98bd4b0403e..4458ad294af7c 100644
--- a/clang/test/Analysis/lifetime-extended-regions.cpp
+++ b/clang/test/Analysis/lifetime-extended-regions.cpp
@@ -120,10 +120,11 @@ 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]+}}} }}
-
- // 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`
+
+ // 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_analyzer_dump(defaultInitExtended.ry); // expected-warning {{Unknown }}
}
diff --git a/clang/test/CXX/drs/cwg16xx.cpp b/clang/test/CXX/drs/cwg16xx.cpp
index cf6b45ceabf2c..82ef871939d2c 100644
--- a/clang/test/CXX/drs/cwg16xx.cpp
+++ b/clang/test/CXX/drs/cwg16xx.cpp
@@ -483,8 +483,6 @@ 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 323e56f9c5278..054ce5a4f4b70 100644
--- a/clang/test/CXX/drs/cwg18xx.cpp
+++ b/clang/test/CXX/drs/cwg18xx.cpp
@@ -206,19 +206,28 @@ namespace cwg1814 { // cwg1814: yes
#endif
}
-namespace cwg1815 { // cwg1815: no
+namespace cwg1815 { // cwg1815: 19
#if __cplusplus >= 201402L
- // FIXME: needs codegen test
- struct A { int &&r = 0; }; // #cwg1815-A
+ struct A { int &&r = 0; };
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 5554363cc69ab..a6d2adfd1fd2c 100644
--- a/clang/test/CXX/special/class.temporary/p6.cpp
+++ b/clang/test/CXX/special/class.temporary/p6.cpp
@@ -269,6 +269,40 @@ 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 ec9b2927880bd..901123bfb359f 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; }; // expected-note 2{{default member initializer}}
+struct A { int &&r = 0; };
struct B { A x, y; };
-B b = {}; // expected-warning 2{{lifetime extension of temporary created by
aggregate initialization using a default member initializer is not yet
supported}}
+B b = {}; // expected-no-diagnostics
}
diff --git a/clang/test/SemaCXX/cxx11-default-member-initializers.cpp
b/clang/test/SemaCXX/cxx11-default-member-initializers.cpp
index dd8e9c6b7fc11..a1f6cab787ef7 100644
--- a/clang/test/SemaCXX/cxx11-default-member-initializers.cpp
+++ b/clang/test/SemaCXX/cxx11-default-member-initializers.cpp
@@ -27,6 +27,101 @@ 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
+
+namespace test_rebuild2 {
+struct F {
+ int g;
+};
+struct H {};
+struct I {
+ I(const F &);
+ I(H);
+};
+struct L {
+ I i = I({.g = 0});
+};
+struct N : L {};
+
+void f() {
+ delete new L; // Ok
+ delete new N; // Ok
+}
+} // namespace test_rebuild2
+
+#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 0865dafe4bf92..21e05f19be0ca 100644
--- a/clang/test/SemaCXX/eval-crashes.cpp
+++ b/clang/test/SemaCXX/eval-crashes.cpp
@@ -25,11 +25,9 @@ namespace pr33140_0b {
}
namespace pr33140_2 {
- // 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 A { int &&r = 0; };
struct B { A x, y; };
- B b = {}; // expected-warning 2{{lifetime extension of temporary created by
aggregate initialization using a default member initializer is not yet
supported}}
+ B b = {};
}
namespace pr33140_3 {
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 937f67981e296..483b0d54adfcb 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -10705,7 +10705,7 @@ <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="none" align="center">No</td>
+ <td class="unreleased" align="center">Clang 19</td>
</tr>
<tr id="1816">
<td><a
href="https://cplusplus.github.io/CWG/issues/1816.html";>1816</a></td>
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