[Concepts] Placeholder constraints and abbreviated templates
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Resubmit after fixing MSAN failures caused by incomplete initialization of AutoTypeLocs in TypeSpecLocFiller.
Differential Revision: https://reviews.llvm.org/D65042
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 342ac20..5351ac3 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -6576,6 +6576,17 @@
void TypeLocReader::VisitAutoTypeLoc(AutoTypeLoc TL) {
TL.setNameLoc(readSourceLocation());
+ if (Reader.readBool()) {
+ TL.setNestedNameSpecifierLoc(ReadNestedNameSpecifierLoc());
+ TL.setTemplateKWLoc(readSourceLocation());
+ TL.setConceptNameLoc(readSourceLocation());
+ TL.setFoundDecl(Reader.readDeclAs<NamedDecl>());
+ TL.setLAngleLoc(readSourceLocation());
+ TL.setRAngleLoc(readSourceLocation());
+ for (unsigned i = 0, e = TL.getNumArgs(); i != e; ++i)
+ TL.setArgLocInfo(i, Reader.readTemplateArgumentLocInfo(
+ TL.getTypePtr()->getArg(i).getKind()));
+ }
}
void TypeLocReader::VisitDeducedTemplateSpecializationTypeLoc(
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 4fd079e..093b69a 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2317,12 +2317,12 @@
D->setDeclaredWithTypename(Record.readInt());
- if (Record.readInt()) {
+ if (Record.readBool()) {
NestedNameSpecifierLoc NNS = Record.readNestedNameSpecifierLoc();
DeclarationNameInfo DN = Record.readDeclarationNameInfo();
- ConceptDecl *NamedConcept = cast<ConceptDecl>(Record.readDecl());
+ ConceptDecl *NamedConcept = Record.readDeclAs<ConceptDecl>();
const ASTTemplateArgumentListInfo *ArgsAsWritten = nullptr;
- if (Record.readInt())
+ if (Record.readBool())
ArgsAsWritten = Record.readASTTemplateArgumentListInfo();
Expr *ImmediatelyDeclaredConstraint = Record.readExpr();
D->setTypeConstraint(NNS, DN, /*FoundDecl=*/nullptr, NamedConcept,
@@ -2340,6 +2340,8 @@
// TemplateParmPosition.
D->setDepth(Record.readInt());
D->setPosition(Record.readInt());
+ if (D->hasPlaceholderTypeConstraint())
+ D->setPlaceholderTypeConstraint(Record.readExpr());
if (D->isExpandedParameterPack()) {
auto TypesAndInfos =
D->getTrailingObjects<std::pair<QualType, TypeSourceInfo *>>();
@@ -3823,13 +3825,19 @@
HasTypeConstraint);
break;
}
- case DECL_NON_TYPE_TEMPLATE_PARM:
- D = NonTypeTemplateParmDecl::CreateDeserialized(Context, ID);
- break;
- case DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK:
+ case DECL_NON_TYPE_TEMPLATE_PARM: {
+ bool HasTypeConstraint = Record.readInt();
D = NonTypeTemplateParmDecl::CreateDeserialized(Context, ID,
- Record.readInt());
+ HasTypeConstraint);
break;
+ }
+ case DECL_EXPANDED_NON_TYPE_TEMPLATE_PARM_PACK: {
+ bool HasTypeConstraint = Record.readInt();
+ D = NonTypeTemplateParmDecl::CreateDeserialized(Context, ID,
+ Record.readInt(),
+ HasTypeConstraint);
+ break;
+ }
case DECL_TEMPLATE_TEMPLATE_PARM:
D = TemplateTemplateParmDecl::CreateDeserialized(Context, ID);
break;
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index c216b14..79f7d57 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -349,6 +349,18 @@
void TypeLocWriter::VisitAutoTypeLoc(AutoTypeLoc TL) {
Record.AddSourceLocation(TL.getNameLoc());
+ Record.push_back(TL.isConstrained());
+ if (TL.isConstrained()) {
+ Record.AddNestedNameSpecifierLoc(TL.getNestedNameSpecifierLoc());
+ Record.AddSourceLocation(TL.getTemplateKWLoc());
+ Record.AddSourceLocation(TL.getConceptNameLoc());
+ Record.AddDeclRef(TL.getFoundDecl());
+ Record.AddSourceLocation(TL.getLAngleLoc());
+ Record.AddSourceLocation(TL.getRAngleLoc());
+ for (unsigned I = 0; I < TL.getNumArgs(); ++I)
+ Record.AddTemplateArgumentLocInfo(TL.getTypePtr()->getArg(I).getKind(),
+ TL.getArgLocInfo(I));
+ }
}
void TypeLocWriter::VisitDeducedTemplateSpecializationTypeLoc(
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 459e617..472136d 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -1675,6 +1675,8 @@
// For an expanded parameter pack, record the number of expansion types here
// so that it's easier for deserialization to allocate the right amount of
// memory.
+ Expr *TypeConstraint = D->getPlaceholderTypeConstraint();
+ Record.push_back(!!TypeConstraint);
if (D->isExpandedParameterPack())
Record.push_back(D->getNumExpansionTypes());
@@ -1682,6 +1684,8 @@
// TemplateParmPosition.
Record.push_back(D->getDepth());
Record.push_back(D->getPosition());
+ if (TypeConstraint)
+ Record.AddStmt(TypeConstraint);
if (D->isExpandedParameterPack()) {
for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {