https://github.com/yronglin updated
https://github.com/llvm/llvm-project/pull/87933
>From 9fba6da7cb1ffbc7d46b69c6ac0cfd15a89c4b56 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Mon, 8 Apr 2024 01:38:23 +0800
Subject: [PATCH 1/6] [Clang] 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 | 6 ---
clang/lib/Sema/SemaExpr.cpp | 16 ++++----
clang/lib/Sema/SemaInit.cpp | 39 +++++++++++++------
.../Analysis/lifetime-extended-regions.cpp | 2 +-
clang/test/CXX/drs/dr16xx.cpp | 2 -
clang/test/CXX/drs/dr18xx.cpp | 5 +--
clang/test/CXX/special/class.temporary/p6.cpp | 20 ++++++++++
clang/test/SemaCXX/constexpr-default-arg.cpp | 4 +-
clang/test/SemaCXX/eval-crashes.cpp | 6 +--
9 files changed, 62 insertions(+), 38 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index a1dda2d2461c3..ba779e83d2afd 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10010,12 +10010,6 @@ 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 8db4fffeecfe3..b2e0f2a2a6011 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6338,10 +6338,9 @@ 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();
@@ -6377,7 +6376,7 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
Expr *Init = nullptr;
bool NestedDefaultChecking = isCheckingDefaultArgumentOrInitializer();
-
+ bool InLifetimeExtendingContext = isInLifetimeExtendingContext();
EnterExpressionEvaluationContext EvalContext(
*this, ExpressionEvaluationContext::PotentiallyEvaluated, Field);
@@ -6412,11 +6411,14 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
ImmediateCallVisitor V(getASTContext());
if (!NestedDefaultChecking)
V.TraverseDecl(Field);
- if (V.HasImmediateCalls) {
+ if (V.HasImmediateCalls || InLifetimeExtendingContext) {
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;
@@ -6424,7 +6426,7 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
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/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index a75e9925a4314..842412cd674d8 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -710,6 +710,26 @@ void InitListChecker::FillInEmptyInitForField(unsigned
Init, FieldDecl *Field,
if (VerifyOnly)
return;
+ // Enter a lifetime extension context, then we can support lifetime
+ // extension of temporary created by aggregate initialization using a
+ // default member initializer (DR1815 https://wg21.link/CWG1815).
+ //
+ // In a lifetime extension context, BuildCXXDefaultInitExpr will clone
the
+ // initializer expression on each use that would lifetime extend its
+ // temporaries.
+ EnterExpressionEvaluationContext LifetimeExtensionContext(
+ SemaRef, Sema::ExpressionEvaluationContext::PotentiallyEvaluated,
+ /*LambdaContextDecl=*/nullptr,
+ Sema::ExpressionEvaluationContextRecord::EK_Other, true);
+
+ // Lifetime extension in default-member-init.
+ auto &LastRecord = SemaRef.ExprEvalContexts.back();
+
+ // Just copy previous record, make sure we haven't forget anything.
+ LastRecord =
+ SemaRef.ExprEvalContexts[SemaRef.ExprEvalContexts.size() - 2];
+ LastRecord.InLifetimeExtendingContext = true;
+
ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
if (DIE.isInvalid()) {
hadError = true;
@@ -7699,6 +7719,8 @@ static void
visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
// Step into CXXDefaultInitExprs so we can diagnose cases where a
// constructor inherits one as an implicit mem-initializer.
if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
+ assert(DIE->hasRewrittenInit() &&
+ "CXXDefaultInitExpr must has rewritten init");
Path.push_back(
{IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
Init = DIE->getExpr();
@@ -8193,6 +8215,11 @@ void Sema::checkInitializerLifetime(const
InitializedEntity &Entity,
}
switch (shouldLifetimeExtendThroughPath(Path)) {
+ case PathLifetimeKind::ShouldExtend:
+ // We're supposed to lifetime-extend the temporary along this path (per
+ // the resolution of DR1815), we supported that by clone the
initializer
+ // expression on each use that would lifetime extend its temporaries.
+ [[fallthrough]];
case PathLifetimeKind::Extend:
// Update the storage duration of the materialized temporary.
// FIXME: Rebuild the expression instead of mutating it.
@@ -8200,18 +8227,6 @@ 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/Analysis/lifetime-extended-regions.cpp
b/clang/test/Analysis/lifetime-extended-regions.cpp
index 4e98bd4b0403e..8df9b8a54a7e0 100644
--- a/clang/test/Analysis/lifetime-extended-regions.cpp
+++ b/clang/test/Analysis/lifetime-extended-regions.cpp
@@ -122,7 +122,7 @@ void aggregateWithReferences() {
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`)
+ // that are created from default member initializer (see
`warn_unsupported_lifetime_extension` from `-Wdangling`) (Supported now).
RefAggregate defaultInitExtended{i}; // clang-bug does not extend `Composite`
clang_analyzer_dump(defaultInitExtended.ry); // expected-warning {{Unknown }}
}
diff --git a/clang/test/CXX/drs/dr16xx.cpp b/clang/test/CXX/drs/dr16xx.cpp
index f4d6c04fb8e07..52002a7d0db00 100644
--- a/clang/test/CXX/drs/dr16xx.cpp
+++ b/clang/test/CXX/drs/dr16xx.cpp
@@ -484,8 +484,6 @@ namespace dr1696 { // dr1696: 7
const A &a = A(); // #dr1696-D1-a
};
D1 d1 = {}; // #dr1696-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@#dr1696-D1-a {{initializing field 'a' with default
member initializer}}
struct D2 {
const A &a = A(); // #dr1696-D2-a
diff --git a/clang/test/CXX/drs/dr18xx.cpp b/clang/test/CXX/drs/dr18xx.cpp
index e78730e8992cf..52a90ea3a05d2 100644
--- a/clang/test/CXX/drs/dr18xx.cpp
+++ b/clang/test/CXX/drs/dr18xx.cpp
@@ -206,13 +206,10 @@ namespace dr1814 { // dr1814: yes
#endif
}
-namespace dr1815 { // dr1815: no
+namespace dr1815 { // dr1815: yes
#if __cplusplus >= 201402L
- // FIXME: needs codegen test
struct A { int &&r = 0; }; // #dr1815-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@#dr1815-A {{initializing field 'r' with default member
initializer}}
struct B { int &&r = 0; }; // #dr1815-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}}
diff --git a/clang/test/CXX/special/class.temporary/p6.cpp
b/clang/test/CXX/special/class.temporary/p6.cpp
index 5554363cc69ab..002bf3e1c2674 100644
--- a/clang/test/CXX/special/class.temporary/p6.cpp
+++ b/clang/test/CXX/special/class.temporary/p6.cpp
@@ -269,6 +269,26 @@ 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() {}
+ };
+
+ // CHECK: void @_Z12check_dr1815v()
+ // CHECK: call void @_ZZ12check_dr1815vEN1BD1Ev(
+ // CHECK: call void @_ZZ12check_dr1815vEN1AD1Ev(
+ B a = {};
+#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 7c88369282954..8510a6ddc8039 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/eval-crashes.cpp
b/clang/test/SemaCXX/eval-crashes.cpp
index 017df977b26b7..a06f60f71e9c7 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 {
>From bf6f9df9f1b06247bfbe92a1c3409f8b4f37ce83 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Mon, 15 Apr 2024 23:20:44 +0800
Subject: [PATCH 2/6] [Clang] Fix tests
Signed-off-by: yronglin <yronglin...@gmail.com>
---
clang/test/AST/ast-dump-default-init-json.cpp | 6 +++---
clang/test/AST/ast-dump-default-init.cpp | 2 +-
clang/test/CXX/drs/dr16xx.cpp | 2 +-
clang/test/CXX/drs/dr18xx.cpp | 4 ++--
4 files changed, 7 insertions(+), 7 deletions(-)
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 9fe945ee6e932..10dbecdb525f2 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/CXX/drs/dr16xx.cpp b/clang/test/CXX/drs/dr16xx.cpp
index d8e1bbfda95d5..d3c1313fc034a 100644
--- a/clang/test/CXX/drs/dr16xx.cpp
+++ b/clang/test/CXX/drs/dr16xx.cpp
@@ -483,7 +483,7 @@ namespace cwg1696 { // cwg1696: 7
// cxx11-note@#cwg1696-D1-a {{initializing field 'a' with default member
initializer}}
const A &a = A(); // #cwg1696-D1-a
};
- D1 d1 = {}; // #dr1696-d1
+ D1 d1 = {}; // #cwg1696-d1
struct D2 {
const A &a = A(); // #cwg1696-D2-a
diff --git a/clang/test/CXX/drs/dr18xx.cpp b/clang/test/CXX/drs/dr18xx.cpp
index e3df50e8cf34d..6b4b854a63dce 100644
--- a/clang/test/CXX/drs/dr18xx.cpp
+++ b/clang/test/CXX/drs/dr18xx.cpp
@@ -206,9 +206,9 @@ namespace cwg1814 { // cwg1814: yes
#endif
}
-namespace dr1815 { // dr1815: yes
+namespace cwg1815 { // cwg1815: yes
#if __cplusplus >= 201402L
- struct A { int &&r = 0; };
+ struct A { int &&r = 0; };
A a = {};
struct B { int &&r = 0; }; // #cwg1815-B
>From 8df75e24f9295f229766ebc02bad3a3cdcc47a38 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Thu, 25 Apr 2024 07:50:18 +0800
Subject: [PATCH 3/6] Update cxx_dr_status.html
Signed-off-by: yronglin <yronglin...@gmail.com>
---
clang/www/cxx_dr_status.html | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 83b71e7c122d1..235f7ed75a21f 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="none" align="center">No</td>
+ <td class="full" align="center">Clang 19</td>
</tr>
<tr id="1816">
<td><a
href="https://cplusplus.github.io/CWG/issues/1816.html";>1816</a></td>
>From 727ccfe2365344dd6bddb98e32ea957f0d280869 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Wed, 8 May 2024 23:43:00 +0800
Subject: [PATCH 4/6] Address review comments, but static analyzer's test still
WIP
Signed-off-by: yronglin <yronglin...@gmail.com>
---
clang/lib/Sema/SemaExpr.cpp | 17 ++++++++--
clang/lib/Sema/SemaInit.cpp | 34 +------------------
clang/test/CXX/drs/dr18xx.cpp | 12 +++++++
clang/test/CXX/special/class.temporary/p6.cpp | 22 +++++++++---
clang/www/cxx_dr_status.html | 2 +-
5 files changed, 47 insertions(+), 40 deletions(-)
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index a79cd598d2acc..bb6c931f34c48 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6393,7 +6393,18 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
ImmediateCallVisitor V(getASTContext());
if (!NestedDefaultChecking)
V.TraverseDecl(Field);
- if (V.HasImmediateCalls || InLifetimeExtendingContext) {
+
+ // 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 =
@@ -6401,9 +6412,11 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
// 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);
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index cc7efedfa4ec7..0e30078fcc741 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -711,26 +711,6 @@ void InitListChecker::FillInEmptyInitForField(unsigned
Init, FieldDecl *Field,
if (VerifyOnly)
return;
- // Enter a lifetime extension context, then we can support lifetime
- // extension of temporary created by aggregate initialization using a
- // default member initializer (DR1815 https://wg21.link/CWG1815).
- //
- // In a lifetime extension context, BuildCXXDefaultInitExpr will clone
the
- // initializer expression on each use that would lifetime extend its
- // temporaries.
- EnterExpressionEvaluationContext LifetimeExtensionContext(
- SemaRef, Sema::ExpressionEvaluationContext::PotentiallyEvaluated,
- /*LambdaContextDecl=*/nullptr,
- Sema::ExpressionEvaluationContextRecord::EK_Other, true);
-
- // Lifetime extension in default-member-init.
- auto &LastRecord = SemaRef.ExprEvalContexts.back();
-
- // Just copy previous record, make sure we haven't forget anything.
- LastRecord =
- SemaRef.ExprEvalContexts[SemaRef.ExprEvalContexts.size() - 2];
- LastRecord.InLifetimeExtendingContext = true;
-
ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
if (DIE.isInvalid()) {
hadError = true;
@@ -7720,8 +7700,6 @@ static void
visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
// Step into CXXDefaultInitExprs so we can diagnose cases where a
// constructor inherits one as an implicit mem-initializer.
if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
- assert(DIE->hasRewrittenInit() &&
- "CXXDefaultInitExpr must has rewritten init");
Path.push_back(
{IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
Init = DIE->getExpr();
@@ -8087,11 +8065,6 @@ 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
};
@@ -8103,7 +8076,7 @@ shouldLifetimeExtendThroughPath(const IndirectLocalPath
&Path) {
PathLifetimeKind Kind = PathLifetimeKind::Extend;
for (auto Elem : Path) {
if (Elem.Kind == IndirectLocalPathEntry::DefaultInit)
- Kind = PathLifetimeKind::ShouldExtend;
+ Kind = PathLifetimeKind::Extend;
else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit)
return PathLifetimeKind::NoExtend;
}
@@ -8216,11 +8189,6 @@ void Sema::checkInitializerLifetime(const
InitializedEntity &Entity,
}
switch (shouldLifetimeExtendThroughPath(Path)) {
- case PathLifetimeKind::ShouldExtend:
- // We're supposed to lifetime-extend the temporary along this path (per
- // the resolution of DR1815), we supported that by clone the
initializer
- // expression on each use that would lifetime extend its temporaries.
- [[fallthrough]];
case PathLifetimeKind::Extend:
// Update the storage duration of the materialized temporary.
// FIXME: Rebuild the expression instead of mutating it.
diff --git a/clang/test/CXX/drs/dr18xx.cpp b/clang/test/CXX/drs/dr18xx.cpp
index 6b4b854a63dce..a96a06406e8a4 100644
--- a/clang/test/CXX/drs/dr18xx.cpp
+++ b/clang/test/CXX/drs/dr18xx.cpp
@@ -216,6 +216,18 @@ namespace cwg1815 { // cwg1815: yes
// 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 002bf3e1c2674..a6d2adfd1fd2c 100644
--- a/clang/test/CXX/special/class.temporary/p6.cpp
+++ b/clang/test/CXX/special/class.temporary/p6.cpp
@@ -281,11 +281,25 @@ void check_dr1815() { // dr1815: yes
A &&a = A{};
~B() {}
};
-
- // CHECK: void @_Z12check_dr1815v()
- // CHECK: call void @_ZZ12check_dr1815vEN1BD1Ev(
- // CHECK: call void @_ZZ12check_dr1815vEN1AD1Ev(
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
}
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 235f7ed75a21f..ba7a67e4a8480 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="full" align="center">Clang 19</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>
>From 84b5a946b39f33d6e05de28530e0fec401028107 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Sun, 12 May 2024 14:36:09 +0800
Subject: [PATCH 5/6] Add comments to explain static analyzer need update
Signed-off-by: yronglin <yronglin...@gmail.com>
---
clang/test/Analysis/lifetime-extended-regions.cpp | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/clang/test/Analysis/lifetime-extended-regions.cpp
b/clang/test/Analysis/lifetime-extended-regions.cpp
index 8df9b8a54a7e0..5a85b9f2a27aa 100644
--- a/clang/test/Analysis/lifetime-extended-regions.cpp
+++ b/clang/test/Analysis/lifetime-extended-regions.cpp
@@ -120,9 +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]+}}} }}
-
- // 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`) (Supported now).
+
+ // 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-bug does not extend `Composite`
clang_analyzer_dump(defaultInitExtended.ry); // expected-warning {{Unknown }}
}
>From 81eb8ff1feb0f24e203e3ff91e75f2780c519ba9 Mon Sep 17 00:00:00 2001
From: yronglin <yronglin...@gmail.com>
Date: Sun, 12 May 2024 14:39:08 +0800
Subject: [PATCH 6/6] Remove comments
Signed-off-by: yronglin <yronglin...@gmail.com>
---
clang/test/Analysis/lifetime-extended-regions.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/test/Analysis/lifetime-extended-regions.cpp
b/clang/test/Analysis/lifetime-extended-regions.cpp
index 5a85b9f2a27aa..4458ad294af7c 100644
--- a/clang/test/Analysis/lifetime-extended-regions.cpp
+++ b/clang/test/Analysis/lifetime-extended-regions.cpp
@@ -124,7 +124,7 @@ void aggregateWithReferences() {
// 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-bug does not extend `Composite`
+ RefAggregate defaultInitExtended{i};
clang_analyzer_dump(defaultInitExtended.ry); // expected-warning {{Unknown }}
}
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