Model type attributes as regular Attrs.

Specifically, AttributedType now tracks a regular attr::Kind rather than
having its own parallel Kind enumeration, and AttributedTypeLoc now
holds an Attr* instead of holding an ad-hoc collection of Attr fields.

Differential Revision: https://reviews.llvm.org/D50526

This reinstates r339623, reverted in r339638, with a fix to not fail
template instantiation if we instantiate a QualType with no associated
type source information and we encounter an AttributedType.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@340215 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 81 insertions, 44 deletions

diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index a6f624e326..a9acf4e2f4 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -6455,6 +6455,10 @@ class TypeLocReader : public TypeLocVisitor<TypeLocReader> {
     return Reader->ReadNestedNameSpecifierLoc(*F, Record, Idx);
   }
 
+  Attr *ReadAttr() {
+    return Reader->ReadAttr(*F, Record, Idx);
+  }
+
 public:
   TypeLocReader(ModuleFile &F, ASTReader &Reader,
                 const ASTReader::RecordData &Record, unsigned &Idx)
@@ -6646,20 +6650,7 @@ void TypeLocReader::VisitEnumTypeLoc(EnumTypeLoc TL) {
 }
 
 void TypeLocReader::VisitAttributedTypeLoc(AttributedTypeLoc TL) {
-  TL.setAttrNameLoc(ReadSourceLocation());
-  if (TL.hasAttrOperand()) {
-    SourceRange range;
-    range.setBegin(ReadSourceLocation());
-    range.setEnd(ReadSourceLocation());
-    TL.setAttrOperandParensRange(range);
-  }
-  if (TL.hasAttrExprOperand()) {
-    if (Record[Idx++])
-      TL.setAttrExprOperand(Reader->ReadExpr(*F));
-    else
-      TL.setAttrExprOperand(nullptr);
-  } else if (TL.hasAttrEnumOperand())
-    TL.setAttrEnumOperandLoc(ReadSourceLocation());
+  TL.setAttr(ReadAttr());
 }
 
 void TypeLocReader::VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 47484f8b38..00fad25eea 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -2648,19 +2648,72 @@ void ASTDeclReader::VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D) {
 // Attribute Reading
 //===----------------------------------------------------------------------===//
 
-/// Reads attributes from the current stream position.
-void ASTReader::ReadAttributes(ASTRecordReader &Record, AttrVec &Attrs) {
-  for (unsigned i = 0, e = Record.readInt(); i != e; ++i) {
-    Attr *New = nullptr;
-    auto Kind = (attr::Kind)Record.readInt();
-    SourceRange Range = Record.readSourceRange();
-    ASTContext &Context = getContext();
+namespace {
+class AttrReader {
+  ModuleFile *F;
+  ASTReader *Reader;
+  const ASTReader::RecordData &Record;
+  unsigned &Idx;
 
-#include "clang/Serialization/AttrPCHRead.inc"
+public:
+  AttrReader(ModuleFile &F, ASTReader &Reader,
+             const ASTReader::RecordData &Record, unsigned &Idx)
+      : F(&F), Reader(&Reader), Record(Record), Idx(Idx) {}
+
+  const uint64_t &readInt() { return Record[Idx++]; }
+
+  SourceRange readSourceRange() {
+    return Reader->ReadSourceRange(*F, Record, Idx);
+  }
+
+  Expr *readExpr() { return Reader->ReadExpr(*F); }
+
+  std::string readString() {
+    return Reader->ReadString(Record, Idx);
+  }
+
+  TypeSourceInfo *getTypeSourceInfo() {
+    return Reader->GetTypeSourceInfo(*F, Record, Idx);
+  }
+
+  IdentifierInfo *getIdentifierInfo() {
+    return Reader->GetIdentifierInfo(*F, Record, Idx);
+  }
 
-    assert(New && "Unable to decode attribute?");
-    Attrs.push_back(New);
+  VersionTuple readVersionTuple() {
+    return ASTReader::ReadVersionTuple(Record, Idx);
   }
+
+  template <typename T> T *GetLocalDeclAs(uint32_t LocalID) {
+    return cast_or_null<T>(Reader->GetLocalDecl(*F, LocalID));
+  }
+};
+}
+
+Attr *ASTReader::ReadAttr(ModuleFile &M, const RecordData &Rec,
+                          unsigned &Idx) {
+  AttrReader Record(M, *this, Rec, Idx);
+  auto V = Record.readInt();
+  if (!V)
+    return nullptr;
+
+  Attr *New = nullptr;
+  // Kind is stored as a 1-based integer because 0 is used to indicate a null
+  // Attr pointer.
+  auto Kind = static_cast<attr::Kind>(V - 1);
+  SourceRange Range = Record.readSourceRange();
+  ASTContext &Context = getContext();
+
+#include "clang/Serialization/AttrPCHRead.inc"
+
+  assert(New && "Unable to decode attribute?");
+  return New;
+}
+
+/// Reads attributes from the current stream position.
+void ASTReader::ReadAttributes(ASTRecordReader &Record, AttrVec &Attrs) {
+  for (unsigned I = 0, E = Record.readInt(); I != E; ++I)
+    Attrs.push_back(Record.readAttr());
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 99606fcca5..1400c873d4 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -770,19 +770,7 @@ void TypeLocWriter::VisitEnumTypeLoc(EnumTypeLoc TL) {
 }
 
 void TypeLocWriter::VisitAttributedTypeLoc(AttributedTypeLoc TL) {
-  Record.AddSourceLocation(TL.getAttrNameLoc());
-  if (TL.hasAttrOperand()) {
-    SourceRange range = TL.getAttrOperandParensRange();
-    Record.AddSourceLocation(range.getBegin());
-    Record.AddSourceLocation(range.getEnd());
-  }
-  if (TL.hasAttrExprOperand()) {
-    Expr *operand = TL.getAttrExprOperand();
-    Record.push_back(operand ? 1 : 0);
-    if (operand) Record.AddStmt(operand);
-  } else if (TL.hasAttrEnumOperand()) {
-    Record.AddSourceLocation(TL.getAttrEnumOperandLoc());
-  }
+  Record.AddAttr(TL.getAttr());
 }
 
 void TypeLocWriter::VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
@@ -4481,16 +4469,21 @@ void ASTWriter::WriteModuleFileExtension(Sema &SemaRef,
 // General Serialization Routines
 //===----------------------------------------------------------------------===//
 
-/// Emit the list of attributes to the specified record.
-void ASTRecordWriter::AddAttributes(ArrayRef<const Attr *> Attrs) {
+void ASTRecordWriter::AddAttr(const Attr *A) {
   auto &Record = *this;
-  Record.push_back(Attrs.size());
-  for (const auto *A : Attrs) {
-    Record.push_back(A->getKind()); // FIXME: stable encoding, target attrs
-    Record.AddSourceRange(A->getRange());
+  if (!A)
+    return Record.push_back(0);
+  Record.push_back(A->getKind() + 1); // FIXME: stable encoding, target attrs
+  Record.AddSourceRange(A->getRange());
 
 #include "clang/Serialization/AttrPCHWrite.inc"
-  }
+}
+
+/// Emit the list of attributes to the specified record.
+void ASTRecordWriter::AddAttributes(ArrayRef<const Attr *> Attrs) {
+  push_back(Attrs.size());
+  for (const auto *A : Attrs)
+    AddAttr(A);
 }
 
 void ASTWriter::AddToken(const Token &Tok, RecordDataImpl &Record) {