[PATCH] D65022: [Sema] Always instantiate the initializer of a variable template with undeduced type (8.0 regression)
erik.pilkington added a comment.
Hmm, looks like this patch fails to fix the case where we're referencing the
variable in an non-odr use context, since we don't even bother to instantiate
the initializer here:
template
struct S {
template
static constexpr auto x = 43;
};
int main() {
sizeof(S::x);
}
I think we should instantiate the initializer before forming a referencing
expression and marking it used. @rsmith: do you mind if I just land
https://reviews.llvm.org/D65022?id=210905 and file a bug to fix the regression
we're seeing here?
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[PATCH] D65022: [Sema] Always instantiate the initializer of a variable template with undeduced type (8.0 regression)
erik.pilkington updated this revision to Diff 212470.
erik.pilkington added a comment.
Rebase on top of r367367.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D65022/new/
https://reviews.llvm.org/D65022
Files:
clang/lib/Sema/SemaExpr.cpp
clang/lib/Sema/SemaExprMember.cpp
clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
Index: clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
===
--- clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
+++ clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
@@ -424,3 +424,34 @@
}
}
#endif
+
+#ifndef PRECXX11
+namespace auto_variable_instantiate_initializer {
+template struct S {
+ template static constexpr auto v = 1;
+ template static constexpr auto v2 = T{};
+
+ template >
+ void implicit() {
+double d = v2;
+int i2 = v;
+ }
+
+ void implicit_nondep() {
+int i = v;
+double d = v2;
+ }
+};
+
+void useit() {
+ S x;
+ // We used to fail to instantiate the initializer, leading to an auto type
+ // leaking through here.
+ int i = x.v;
+ float j = x.v2;
+
+ x.implicit();
+ x.implicit_nondep();
+}
+}
+ #endif
Index: clang/lib/Sema/SemaExprMember.cpp
===
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -1160,11 +1160,17 @@
}
if (VarTemplateDecl *VarTempl = dyn_cast(MemberDecl)) {
if (VarDecl *Var = getVarTemplateSpecialization(
-VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc))
- return BuildMemberExpr(
+VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc)) {
+ MemberExpr *ME = BuildMemberExpr(
BaseExpr, IsArrow, OpLoc, , TemplateKWLoc, Var, FoundDecl,
/*HadMultipleCandidates=*/false, MemberNameInfo,
Var->getType().getNonReferenceType(), VK_LValue, OK_Ordinary);
+
+ // BuildMemberExpr may have deduced an auto variable's type. Patch back
+ // that type to avoid forming an expression with undeduced type.
+ ME->setType(Var->getType().getNonReferenceType());
+ return ME;
+}
return ExprError();
}
Index: clang/lib/Sema/SemaExpr.cpp
===
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -3163,9 +3163,15 @@
break;
}
-return BuildDeclRefExpr(VD, type, valueKind, NameInfo, , FoundD,
-/*FIXME: TemplateKWLoc*/ SourceLocation(),
-TemplateArgs);
+DeclRefExpr *DRE = BuildDeclRefExpr(
+VD, type, valueKind, NameInfo, , FoundD,
+/*FIXME: TemplateKWLoc*/ SourceLocation(), TemplateArgs);
+
+// BuildDeclRefExpr may have deduced an auto variable's type. Patch back
+// that type to avoid forming an expression with undeduced type.
+if (isa(VD))
+ DRE->setType(VD->getType().getNonReferenceType());
+return DRE;
}
}
Index: clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
===
--- clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
+++ clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
@@ -424,3 +424,34 @@
}
}
#endif
+
+#ifndef PRECXX11
+namespace auto_variable_instantiate_initializer {
+template struct S {
+ template static constexpr auto v = 1;
+ template static constexpr auto v2 = T{};
+
+ template >
+ void implicit() {
+double d = v2;
+int i2 = v;
+ }
+
+ void implicit_nondep() {
+int i = v;
+double d = v2;
+ }
+};
+
+void useit() {
+ S x;
+ // We used to fail to instantiate the initializer, leading to an auto type
+ // leaking through here.
+ int i = x.v;
+ float j = x.v2;
+
+ x.implicit();
+ x.implicit_nondep();
+}
+}
+ #endif
Index: clang/lib/Sema/SemaExprMember.cpp
===
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -1160,11 +1160,17 @@
}
if (VarTemplateDecl *VarTempl = dyn_cast(MemberDecl)) {
if (VarDecl *Var = getVarTemplateSpecialization(
-VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc))
- return BuildMemberExpr(
+VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc)) {
+ MemberExpr *ME = BuildMemberExpr(
BaseExpr, IsArrow, OpLoc, , TemplateKWLoc, Var, FoundDecl,
/*HadMultipleCandidates=*/false, MemberNameInfo,
Var->getType().getNonReferenceType(), VK_LValue, OK_Ordinary);
+
+ // BuildMemberExpr may have deduced an auto variable's type. Patch back
+ // that type to avoid forming an expression with undeduced type.
+ ME->setType(Var->getType().getNonReferenceType());
+ return ME;
+}
return ExprError();
}
Index: clang/lib/Sema/SemaExpr.cpp
===
---
[PATCH] D65022: [Sema] Always instantiate the initializer of a variable template with undeduced type (8.0 regression)
erik.pilkington updated this revision to Diff 212026.
erik.pilkington added a comment.
Fix the type of the MemberExpr/DeclRefExpr after instantiating the variable
initializer.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D65022/new/
https://reviews.llvm.org/D65022
Files:
clang/lib/Sema/SemaExpr.cpp
clang/lib/Sema/SemaExprMember.cpp
clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
Index: clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
===
--- clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
+++ clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
@@ -395,3 +395,34 @@
}
int = B::template n; // expected-error {{use of variable template 'n'
requires template arguments}}
}
+
+#ifndef PRECXX11
+namespace auto_variable_instantiate_initializer {
+template struct S {
+ template static constexpr auto v = 1;
+ template static constexpr auto v2 = T{};
+
+ template >
+ void implicit() {
+double d = v2;
+int i2 = v;
+ }
+
+ void implicit_nondep() {
+int i = v;
+double d = v2;
+ }
+};
+
+void useit() {
+ S x;
+ // We used to fail to instantiate the initializer, leading to an auto type
+ // leaking through here.
+ int i = x.v;
+ float j = x.v2;
+
+ x.implicit();
+ x.implicit_nondep();
+}
+}
+#endif
Index: clang/lib/Sema/SemaExprMember.cpp
===
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -1160,11 +1160,17 @@
}
if (VarTemplateDecl *VarTempl = dyn_cast(MemberDecl)) {
if (VarDecl *Var = getVarTemplateSpecialization(
-*this, VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc))
- return BuildMemberExpr(
+*this, VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc)) {
+ MemberExpr *ME = BuildMemberExpr(
BaseExpr, IsArrow, OpLoc, , TemplateKWLoc, Var, FoundDecl,
/*HadMultipleCandidates=*/false, MemberNameInfo,
Var->getType().getNonReferenceType(), VK_LValue, OK_Ordinary);
+
+ // BuildMemberExpr may have deduced an auto variable's type. Patch back
+ // that type to avoid forming an expression with undeduced type.
+ ME->setType(Var->getType().getNonReferenceType());
+ return ME;
+}
return ExprError();
}
Index: clang/lib/Sema/SemaExpr.cpp
===
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -3163,9 +3163,15 @@
break;
}
-return BuildDeclRefExpr(VD, type, valueKind, NameInfo, , FoundD,
-/*FIXME: TemplateKWLoc*/ SourceLocation(),
-TemplateArgs);
+DeclRefExpr *DRE = BuildDeclRefExpr(
+VD, type, valueKind, NameInfo, , FoundD,
+/*FIXME: TemplateKWLoc*/ SourceLocation(), TemplateArgs);
+
+// BuildDeclRefExpr may have deduced an auto variable's type. Patch back
+// that type to avoid forming an expression with undeduced type.
+if (isa(VD))
+ DRE->setType(VD->getType().getNonReferenceType());
+return DRE;
}
}
Index: clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
===
--- clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
+++ clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
@@ -395,3 +395,34 @@
}
int = B::template n; // expected-error {{use of variable template 'n' requires template arguments}}
}
+
+#ifndef PRECXX11
+namespace auto_variable_instantiate_initializer {
+template struct S {
+ template static constexpr auto v = 1;
+ template static constexpr auto v2 = T{};
+
+ template >
+ void implicit() {
+double d = v2;
+int i2 = v;
+ }
+
+ void implicit_nondep() {
+int i = v;
+double d = v2;
+ }
+};
+
+void useit() {
+ S x;
+ // We used to fail to instantiate the initializer, leading to an auto type
+ // leaking through here.
+ int i = x.v;
+ float j = x.v2;
+
+ x.implicit();
+ x.implicit_nondep();
+}
+}
+#endif
Index: clang/lib/Sema/SemaExprMember.cpp
===
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -1160,11 +1160,17 @@
}
if (VarTemplateDecl *VarTempl = dyn_cast(MemberDecl)) {
if (VarDecl *Var = getVarTemplateSpecialization(
-*this, VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc))
- return BuildMemberExpr(
+*this, VarTempl, TemplateArgs, MemberNameInfo, TemplateKWLoc)) {
+ MemberExpr *ME = BuildMemberExpr(
BaseExpr, IsArrow, OpLoc, , TemplateKWLoc, Var, FoundDecl,
/*HadMultipleCandidates=*/false, MemberNameInfo,
Var->getType().getNonReferenceType(), VK_LValue, OK_Ordinary);
+
+ // BuildMemberExpr may have deduced an auto variable's type. Patch back
+ // that
[PATCH] D65022: [Sema] Always instantiate the initializer of a variable template with undeduced type (8.0 regression)
rsmith added a comment. Well, this restores an incorrect behaviour: we're not permitted to substitute into the initializer of the variable template here. Can you look into fixing this properly, by instantiating the type when forming the MemberExpr? If not, taking this to fix the regression seems OK, but please file a bug for the introduced misbehaviour. Repository: rC Clang CHANGES SINCE LAST ACTION https://reviews.llvm.org/D65022/new/ https://reviews.llvm.org/D65022 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D65022: [Sema] Always instantiate the initializer of a variable template with undeduced type (8.0 regression)
erik.pilkington created this revision.
erik.pilkington added reviewers: rsmith, rjmccall.
Herald added subscribers: dexonsmith, jkorous.
Herald added a project: clang.
This patch fixes a regression introduced in r359947. Here:
template struct Outer {
template static constexpr auto x = 1;
};
int main() {
Outer x;
int i = x.x;
}
We'd defer the instantiation of the initializer of the variable template when
instantiating Outer (leaving the variable template with an undeduced
type). We do eventually instantiate the initializer and deduce the type of the
variable when we're marking `Outer::x` referenced, but not before
forming a MemberExpr that refers to the undeduced type. I think we could avoid
instantiating the initializer of the variable template here, but that doesn't
appear to be the intent of r359947, so this patch just falls back to the 8.0
behaviour.
Fixes rdar://52619644
Thanks for taking a look!
Erik
Repository:
rC Clang
https://reviews.llvm.org/D65022
Files:
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
Index: clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
===
--- clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
+++ clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
@@ -395,3 +395,20 @@
}
int = B::template n; // expected-error {{use of variable template 'n'
requires template arguments}}
}
+
+#ifndef PRECXX11
+namespace auto_variable_instantiate_initializer {
+template struct S {
+ template static constexpr auto v = 1;
+ template static constexpr auto v2 = T{};
+};
+
+void useit() {
+ S x;
+ // We used to fail to instantiate the initializer, leading to an auto type
+ // leaking through here.
+ int i = x.v;
+ float j = x.v2;
+}
+}
+#endif
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -4506,11 +4506,11 @@
Context.setStaticLocalNumber(NewVar, Context.getStaticLocalNumber(OldVar));
// Figure out whether to eagerly instantiate the initializer.
- if (InstantiatingVarTemplate || InstantiatingVarTemplatePartialSpec) {
-// We're producing a template. Don't instantiate the initializer yet.
- } else if (NewVar->getType()->isUndeducedType()) {
+ if (NewVar->getType()->isUndeducedType()) {
// We need the type to complete the declaration of the variable.
InstantiateVariableInitializer(NewVar, OldVar, TemplateArgs);
+ } else if (InstantiatingVarTemplate || InstantiatingVarTemplatePartialSpec) {
+// We're producing a template. Don't instantiate the initializer yet.
} else if (InstantiatingSpecFromTemplate ||
(OldVar->isInline() && OldVar->isThisDeclarationADefinition() &&
!NewVar->isThisDeclarationADefinition())) {
Index: clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
===
--- clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
+++ clang/test/SemaCXX/cxx1y-variable-templates_in_class.cpp
@@ -395,3 +395,20 @@
}
int = B::template n; // expected-error {{use of variable template 'n' requires template arguments}}
}
+
+#ifndef PRECXX11
+namespace auto_variable_instantiate_initializer {
+template struct S {
+ template static constexpr auto v = 1;
+ template static constexpr auto v2 = T{};
+};
+
+void useit() {
+ S x;
+ // We used to fail to instantiate the initializer, leading to an auto type
+ // leaking through here.
+ int i = x.v;
+ float j = x.v2;
+}
+}
+#endif
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -4506,11 +4506,11 @@
Context.setStaticLocalNumber(NewVar, Context.getStaticLocalNumber(OldVar));
// Figure out whether to eagerly instantiate the initializer.
- if (InstantiatingVarTemplate || InstantiatingVarTemplatePartialSpec) {
-// We're producing a template. Don't instantiate the initializer yet.
- } else if (NewVar->getType()->isUndeducedType()) {
+ if (NewVar->getType()->isUndeducedType()) {
// We need the type to complete the declaration of the variable.
InstantiateVariableInitializer(NewVar, OldVar, TemplateArgs);
+ } else if (InstantiatingVarTemplate || InstantiatingVarTemplatePartialSpec) {
+// We're producing a template. Don't instantiate the initializer yet.
} else if (InstantiatingSpecFromTemplate ||
(OldVar->isInline() && OldVar->isThisDeclarationADefinition() &&
!NewVar->isThisDeclarationADefinition())) {
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