@availability: implement serialization and AST printing

Swift SVN r16010

include/swift/AST/Attr.h

@@ -467,7 +467,7 @@ public:
     : DeclAttribute(DAK_asmname, AtLoc, Range, Implicit),
       Name(Name) {}
 
-  AsmnameAttr(StringRef Name)
+  AsmnameAttr(StringRef Name, bool Implicit)
     : AsmnameAttr(Name, SourceLoc(), SourceRange(), /*Implicit=*/true) {}
 
   /// The symbol name.

include/swift/Serialization/ModuleFormat.h

@@ -964,11 +964,22 @@ namespace decls_block {
 
   using AsmnameDeclAttrLayout = BCRecordLayout<
     Asmname_DECL_ATTR,
+    BCFixed<1>, // implicit flag
     BCBlob      // asmname
   >;
 
+  using AvailabilityDeclAttrLayout = BCRecordLayout<
+    Availability_DECL_ATTR,
+    BCFixed<1>, // implicit flag
+    BCFixed<1>, // is unconditionally unavailable?
+    BCVBR<5>,   // number of bytes in platform string
+    BCVBR<5>,   // number of bytes in message string
+    BCBlob      // platform, followed by message
+  >;
+
   using ObjCDeclAttrLayout = BCRecordLayout<
     ObjC_DECL_ATTR,
+    BCFixed<1>, // implicit flag
     ObjCDeclAttrKindField, // kind
     BCArray<IdentifierIDField>
   >;

lib/AST/Attr.cpp

@@ -109,14 +109,16 @@ void DeclAttribute::print(ASTPrinter &Printer) const {
     Printer << "@availability(";
     auto Attr = cast<AvailabilityAttr>(this);
     if (!Attr->hasPlatform())
-      Printer << '*';
+      Printer << "*";
     else
       Printer << Attr->Platform;
 
+    Printer << ", unavailable";
+
     if (!Attr->Message.empty()) {
       Printer << ", message=\"" << Attr->Message << "\"";
     }
-    Printer << ')';
+    Printer << ")";
     break;
   }
   case DAK_class_protocol:

lib/Serialization/Deserialization.cpp

@@ -1387,14 +1387,33 @@ Decl *ModuleFile::getDecl(DeclID DID, Optional<DeclContext *> ForcedContext,
       DeclAttribute *Attr = nullptr;
       switch (recordID) {
       case decls_block::Asmname_DECL_ATTR:
-        Attr = new (ctx) AsmnameAttr(blobData);
+        bool isImplicit;
+        serialization::decls_block::AsmnameDeclAttrLayout::readRecord(
+            scratch, isImplicit);
+        Attr = new (ctx) AsmnameAttr(blobData, isImplicit);
         break;
 
+      case decls_block::Availability_DECL_ATTR: {
+        bool isImplicit;
+        bool isUnavailable;
+        unsigned platformSize;
+        unsigned messageSize;
+        serialization::decls_block::AvailabilityDeclAttrLayout::readRecord(
+            scratch, isImplicit, isUnavailable, platformSize, messageSize);
+        StringRef platform = blobData.substr(0, platformSize);
+        blobData = blobData.drop_front(platformSize);
+        StringRef message = blobData;
+        Attr = new (ctx) AvailabilityAttr(SourceLoc(), SourceRange(), platform,
+                                          message, isUnavailable, isImplicit);
+        break;
+      }
+
       case decls_block::ObjC_DECL_ATTR: {
+        bool isImplicit;
         uint8_t kind;
         ArrayRef<uint64_t> rawNameIDs;
         serialization::decls_block::ObjCDeclAttrLayout::readRecord(
-            scratch, kind, rawNameIDs);
+            scratch, isImplicit, kind, rawNameIDs);
 
         SmallVector<Identifier, 4> names;
         for (auto nameID : rawNameIDs)

lib/Serialization/Serialization.cpp

@@ -29,6 +29,7 @@
 // This is a template-only header; eventually it should move to llvm/Support.
 #include "clang/Basic/OnDiskHashTable.h"
 
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Bitcode/BitstreamWriter.h"
 #include "llvm/Config/config.h"
@@ -1258,9 +1259,26 @@ void Serializer::writeDeclAttribute(const DeclAttribute *DA) {
 #include "swift/AST/Attr.def"
 
   case DAK_asmname: {
+    auto *theAttr = cast<AsmnameAttr>(DA);
     auto abbrCode = DeclTypeAbbrCodes[AsmnameDeclAttrLayout::Code];
     AsmnameDeclAttrLayout::emitRecord(Out, ScratchRecord, abbrCode,
-                                      cast<AsmnameAttr>(DA)->Name);
+                                      theAttr->isImplicit(),
+                                      theAttr->Name);
+    return;
+  }
+  case DAK_availability: {
+    auto *theAttr = cast<AvailabilityAttr>(DA);
+    llvm::SmallString<32> blob;
+    blob.append(theAttr->Platform);
+    blob.append(theAttr->Message);
+    auto abbrCode = DeclTypeAbbrCodes[AvailabilityDeclAttrLayout::Code];
+    AvailabilityDeclAttrLayout::emitRecord(
+        Out, ScratchRecord, abbrCode,
+        theAttr->isImplicit(),
+        theAttr->IsUnvailable,
+        theAttr->Platform.size(),
+        theAttr->Message.size(),
+        blob);
     return;
   }
   case DAK_objc: {
@@ -1272,11 +1290,10 @@ void Serializer::writeDeclAttribute(const DeclAttribute *DA) {
     auto abbrCode = DeclTypeAbbrCodes[ObjCDeclAttrLayout::Code];
     ObjCDeclAttrLayout::emitRecord(
         Out, ScratchRecord, abbrCode,
+        theAttr->isImplicit(),
         getRawStableObjCDeclAttrKind(theAttr->getKind()), names);
     return;
   }
-  case DAK_availability:
-    llvm_unreachable("not yet serialized");
   }
 }
 
@@ -2378,9 +2395,7 @@ void Serializer::writeAllDeclsAndTypes() {
     registerDeclTypeAbbr<DeclContextLayout>();
     registerDeclTypeAbbr<XRefLayout>();
 
-    registerDeclTypeAbbr<AsmnameDeclAttrLayout>();
-    registerDeclTypeAbbr<ObjCDeclAttrLayout>();
-#define SIMPLE_DECL_ATTR(X, NAME, ...)\
+#define DECL_ATTR(X, NAME, ...) \
     registerDeclTypeAbbr<NAME##DeclAttrLayout>();
 #include "swift/AST/Attr.def"
   }