mizvekov created this revision.
mizvekov published this revision for review.
mizvekov added reviewers: rsmith, rtrieu.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
See PR51708.
Attempting copy elision in dependent contexts with invalid variable,
such as a variable with incomplete type, would cause a crash when attempting
to calculate it's alignment.
The fix is to just skip this optimization on invalid VarDecl, as otherwise this
provides no benefit to error recovery: This functionality does not try to
diagnose anything, it only calculates a flag which will affect where the
variable will be allocated during codegen.
Signed-off-by: Matheus Izvekov <mizve...@gmail.com>
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D109191
Files:
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
Index: clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
===================================================================
--- clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
+++ clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
@@ -518,3 +518,37 @@
template X<int> test_dependent_invalid_decl<int>(); // expected-note
{{requested here}}
} // namespace test_auto_variables
+
+namespace PR51708 {
+
+class a1; // expected-note 4 {{forward declaration of
'PR51708::a1'}}
+template <class> class A2; // expected-note 4 {{template is declared here}}
+using a2 = A2<int>;
+
+template <class b> b f() {
+ // expected-error@-1 {{incomplete result type 'PR51708::a1' in function
definition}}
+ // expected-error@-2 {{implicit instantiation of undefined template
'PR51708::A2<int>}}
+
+ b d;
+ // expected-error@-1 {{variable has incomplete type 'PR51708::a1'}}
+ // expected-error@-2 {{implicit instantiation of undefined template
'PR51708::A2<int>}}
+
+ return d;
+}
+template a1 f<a1>(); // expected-note-re {{in instantiation {{.*}} requested
here}}
+template a2 f<a2>(); // expected-note-re {{in instantiation {{.*}} requested
here}}
+
+template <class b> b g() {
+ // expected-error@-1 {{incomplete result type 'PR51708::a1' in function
definition}}
+ // expected-error@-2 {{implicit instantiation of undefined template
'PR51708::A2<int>}}
+
+ b d __attribute__((aligned(1)));
+ // expected-error@-1 {{variable has incomplete type 'PR51708::a1'}}
+ // expected-error@-2 {{implicit instantiation of undefined template
'PR51708::A2<int>}}
+
+ return d;
+}
+template a1 g<a1>(); // expected-note-re {{in instantiation {{.*}} requested
here}}
+template a2 g<a2>(); // expected-note-re {{in instantiation {{.*}} requested
here}}
+
+} // namespace PR51708
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1087,7 +1087,7 @@
SemaRef.BuildVariableInstantiation(Var, D, TemplateArgs, LateAttrs, Owner,
StartingScope, InstantiatingVarTemplate);
- if (D->isNRVOVariable()) {
+ if (D->isNRVOVariable() && !Var->isInvalidDecl()) {
QualType RT;
if (auto *F = dyn_cast<FunctionDecl>(DC))
RT = F->getReturnType();
Index: clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
===================================================================
--- clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
+++ clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
@@ -518,3 +518,37 @@
template X<int> test_dependent_invalid_decl<int>(); // expected-note {{requested here}}
} // namespace test_auto_variables
+
+namespace PR51708 {
+
+class a1; // expected-note 4 {{forward declaration of 'PR51708::a1'}}
+template <class> class A2; // expected-note 4 {{template is declared here}}
+using a2 = A2<int>;
+
+template <class b> b f() {
+ // expected-error@-1 {{incomplete result type 'PR51708::a1' in function definition}}
+ // expected-error@-2 {{implicit instantiation of undefined template 'PR51708::A2<int>}}
+
+ b d;
+ // expected-error@-1 {{variable has incomplete type 'PR51708::a1'}}
+ // expected-error@-2 {{implicit instantiation of undefined template 'PR51708::A2<int>}}
+
+ return d;
+}
+template a1 f<a1>(); // expected-note-re {{in instantiation {{.*}} requested here}}
+template a2 f<a2>(); // expected-note-re {{in instantiation {{.*}} requested here}}
+
+template <class b> b g() {
+ // expected-error@-1 {{incomplete result type 'PR51708::a1' in function definition}}
+ // expected-error@-2 {{implicit instantiation of undefined template 'PR51708::A2<int>}}
+
+ b d __attribute__((aligned(1)));
+ // expected-error@-1 {{variable has incomplete type 'PR51708::a1'}}
+ // expected-error@-2 {{implicit instantiation of undefined template 'PR51708::A2<int>}}
+
+ return d;
+}
+template a1 g<a1>(); // expected-note-re {{in instantiation {{.*}} requested here}}
+template a2 g<a2>(); // expected-note-re {{in instantiation {{.*}} requested here}}
+
+} // namespace PR51708
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1087,7 +1087,7 @@
SemaRef.BuildVariableInstantiation(Var, D, TemplateArgs, LateAttrs, Owner,
StartingScope, InstantiatingVarTemplate);
- if (D->isNRVOVariable()) {
+ if (D->isNRVOVariable() && !Var->isInvalidDecl()) {
QualType RT;
if (auto *F = dyn_cast<FunctionDecl>(DC))
RT = F->getReturnType();
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