Objective-C: Serialize "more than one decl" state of ObjCMethodList.

This fixes PR21587, what r221933 fixed for regular programs is now also
fixed for decls coming from PCH files.

Use another bit from the count/bits uint16_t for storing the "more than one
decl" bit.  This reduces the number of bits for the count from 14 to 13.
The selector with the most overloads in Cocoa.h has ~55 overloads, so 13 bits
should still be plenty.  Since this changes the meaning of a serialized bit
pattern, also increase clang::serialization::VERSION_MAJOR.

Storing the "more than one decl" state of only the first overload isn't quite
correct, but Sema::AreMultipleMethodsInGlobalPool() currently only looks at
the state of the first overload so it's good enough for now.

llvm-svn: 224892

clang/include/clang/Sema/ObjCMethodList.h

@@ -23,6 +23,7 @@ class ObjCMethodDecl;
 /// \brief a linked list of methods with the same selector name but different
 /// signatures.
 struct ObjCMethodList {
+  // NOTE: If you add any members to this struct, make sure to serialize them.
   /// \brief If there is more than one decl with this signature.
   llvm::PointerIntPair<ObjCMethodDecl *, 1> MethodAndHasMoreThanOneDecl;
   /// \brief The next list object and 2 bits for extra info.

clang/include/clang/Serialization/ASTBitCodes.h

@@ -35,7 +35,7 @@ namespace clang {
     /// Version 4 of AST files also requires that the version control branch and
     /// revision match exactly, since there is no backward compatibility of
     /// AST files at this time.
-    const unsigned VERSION_MAJOR = 5;
+    const unsigned VERSION_MAJOR = 6;
 
     /// \brief AST file minor version number supported by this version of
     /// Clang.

clang/lib/Serialization/ASTReader.cpp

@@ -650,14 +650,14 @@ ASTSelectorLookupTrait::ReadData(Selector, const unsigned char* d,
 
   Result.ID = Reader.getGlobalSelectorID(
       F, endian::readNext<uint32_t, little, unaligned>(d));
-  unsigned NumInstanceMethodsAndBits =
-      endian::readNext<uint16_t, little, unaligned>(d);
-  unsigned NumFactoryMethodsAndBits =
-      endian::readNext<uint16_t, little, unaligned>(d);
-  Result.InstanceBits = NumInstanceMethodsAndBits & 0x3;
-  Result.FactoryBits = NumFactoryMethodsAndBits & 0x3;
-  unsigned NumInstanceMethods = NumInstanceMethodsAndBits >> 2;
-  unsigned NumFactoryMethods = NumFactoryMethodsAndBits >> 2;
+  unsigned FullInstanceBits = endian::readNext<uint16_t, little, unaligned>(d);
+  unsigned FullFactoryBits = endian::readNext<uint16_t, little, unaligned>(d);
+  Result.InstanceBits = FullInstanceBits & 0x3;
+  Result.InstanceHasMoreThanOneDecl = (FullInstanceBits >> 2) & 0x1;
+  Result.FactoryBits = FullFactoryBits & 0x3;
+  Result.FactoryHasMoreThanOneDecl = (FullFactoryBits >> 2) & 0x1;
+  unsigned NumInstanceMethods = FullInstanceBits >> 3;
+  unsigned NumFactoryMethods = FullFactoryBits >> 3;
 
   // Load instance methods
   for (unsigned I = 0; I != NumInstanceMethods; ++I) {
@@ -7061,6 +7061,8 @@ namespace clang { namespace serialization {
     unsigned PriorGeneration;
     unsigned InstanceBits;
     unsigned FactoryBits;
+    bool InstanceHasMoreThanOneDecl;
+    bool FactoryHasMoreThanOneDecl;
     SmallVector<ObjCMethodDecl *, 4> InstanceMethods;
     SmallVector<ObjCMethodDecl *, 4> FactoryMethods;
 
@@ -7068,7 +7070,8 @@ namespace clang { namespace serialization {
     ReadMethodPoolVisitor(ASTReader &Reader, Selector Sel,
                           unsigned PriorGeneration)
         : Reader(Reader), Sel(Sel), PriorGeneration(PriorGeneration),
-          InstanceBits(0), FactoryBits(0) {}
+          InstanceBits(0), FactoryBits(0), InstanceHasMoreThanOneDecl(false),
+          FactoryHasMoreThanOneDecl(false) {}
 
     static bool visit(ModuleFile &M, void *UserData) {
       ReadMethodPoolVisitor *This
@@ -7103,6 +7106,8 @@ namespace clang { namespace serialization {
       This->FactoryMethods.append(Data.Factory.begin(), Data.Factory.end());
       This->InstanceBits = Data.InstanceBits;
       This->FactoryBits = Data.FactoryBits;
+      This->InstanceHasMoreThanOneDecl = Data.InstanceHasMoreThanOneDecl;
+      This->FactoryHasMoreThanOneDecl = Data.FactoryHasMoreThanOneDecl;
       return true;
     }
     
@@ -7118,6 +7123,10 @@ namespace clang { namespace serialization {
 
     unsigned getInstanceBits() const { return InstanceBits; }
     unsigned getFactoryBits() const { return FactoryBits; }
+    bool instanceHasMoreThanOneDecl() const {
+      return InstanceHasMoreThanOneDecl;
+    }
+    bool factoryHasMoreThanOneDecl() const { return FactoryHasMoreThanOneDecl; }
   };
 } } // end namespace clang::serialization
 
@@ -7156,7 +7165,9 @@ void ASTReader::ReadMethodPool(Selector Sel) {
   addMethodsToPool(S, Visitor.getInstanceMethods(), Pos->second.first);
   addMethodsToPool(S, Visitor.getFactoryMethods(), Pos->second.second);
   Pos->second.first.setBits(Visitor.getInstanceBits());
+  Pos->second.first.setHasMoreThanOneDecl(Visitor.instanceHasMoreThanOneDecl());
   Pos->second.second.setBits(Visitor.getFactoryBits());
+  Pos->second.second.setHasMoreThanOneDecl(Visitor.factoryHasMoreThanOneDecl());
 }
 
 void ASTReader::ReadKnownNamespaces(

clang/lib/Serialization/ASTReaderInternals.h

@@ -156,6 +156,8 @@ public:
     SelectorID ID;
     unsigned InstanceBits;
     unsigned FactoryBits;
+    bool InstanceHasMoreThanOneDecl;
+    bool FactoryHasMoreThanOneDecl;
     SmallVector<ObjCMethodDecl *, 2> Instance;
     SmallVector<ObjCMethodDecl *, 2> Factory;
   };

clang/lib/Serialization/ASTWriter.cpp

@@ -2940,13 +2940,20 @@ public:
 
     unsigned InstanceBits = Methods.Instance.getBits();
     assert(InstanceBits < 4);
-    unsigned NumInstanceMethodsAndBits =
-        (NumInstanceMethods << 2) | InstanceBits;
+    unsigned InstanceHasMoreThanOneDeclBit =
+        Methods.Instance.hasMoreThanOneDecl();
+    unsigned FullInstanceBits = (NumInstanceMethods << 3) |
+                                (InstanceHasMoreThanOneDeclBit << 2) |
+                                InstanceBits;
     unsigned FactoryBits = Methods.Factory.getBits();
     assert(FactoryBits < 4);
-    unsigned NumFactoryMethodsAndBits = (NumFactoryMethods << 2) | FactoryBits;
-    LE.write<uint16_t>(NumInstanceMethodsAndBits);
-    LE.write<uint16_t>(NumFactoryMethodsAndBits);
+    unsigned FactoryHasMoreThanOneDeclBit =
+        Methods.Factory.hasMoreThanOneDecl();
+    unsigned FullFactoryBits = (NumFactoryMethods << 3) |
+                               (FactoryHasMoreThanOneDeclBit << 2) |
+                               FactoryBits;
+    LE.write<uint16_t>(FullInstanceBits);
+    LE.write<uint16_t>(FullFactoryBits);
     for (const ObjCMethodList *Method = &Methods.Instance; Method;
          Method = Method->getNext())
       if (Method->getMethod())

clang/test/SemaObjC/attr-deprecated-pch.m

@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -fsyntax-only -DBOTH -verify %s
+// If the decls come from a pch, the behavior shouldn't change:
+// RUN: %clang_cc1 -x objective-c-header %s -emit-pch -o %t
+// RUN: %clang_cc1 -DUSES -include-pch %t -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+// The slightly strange ifdefs are so that the command that builds the gch file
+// doesn't need any -D switches, for these would get embedded in the gch.
+
+#ifndef USES
+@interface Interface1
+- (void)partiallyUnavailableMethod;
+@end
+@interface Interface2
+- (void)partiallyUnavailableMethod __attribute__((unavailable));
+@end
+#endif
+
+#if defined(USES) || defined(BOTH)
+void f(id a) {
+  [a partiallyUnavailableMethod];  // no warning, `a` could be an Interface1.
+}
+#endif