Always initialize 'Expansion' field in SILDeclRef.

Fixes nondeterminism in SIL serialization that fortunately seemed to not
affect anything. Or maybe it did and some random crashes will go away now.

Swift SVN r28577

Author: jrose-apple

include/swift/SIL/SILDeclRef.h

@@ -266,18 +266,14 @@ struct SILDeclRef {
   bool operator==(SILDeclRef rhs) const {
     return loc.getOpaqueValue() == rhs.loc.getOpaqueValue()
       && kind == rhs.kind
+      && Expansion == rhs.Expansion
       && uncurryLevel == rhs.uncurryLevel
       && isForeign == rhs.isForeign
       && isDirectReference == rhs.isDirectReference
       && defaultArgIndex == rhs.defaultArgIndex;
   }
   bool operator!=(SILDeclRef rhs) const {
-    return loc.getOpaqueValue() != rhs.loc.getOpaqueValue()
-      || kind != rhs.kind
-      || uncurryLevel != rhs.uncurryLevel
-      || isForeign != rhs.isForeign
-      || isDirectReference != rhs.isDirectReference
-      || defaultArgIndex != rhs.defaultArgIndex;
+    return !(*this == rhs);
   }
 
   void print(llvm::raw_ostream &os) const;
@@ -294,16 +290,16 @@ struct SILDeclRef {
     // Curry thunks are never foreign.
     bool willBeForeign = isForeign && !willBeCurried;
     bool willBeDirect = isDirectReference;
-    return SILDeclRef(loc.getOpaqueValue(), kind, level,
+    return SILDeclRef(loc.getOpaqueValue(), kind, Expansion, level,
                       willBeCurried, willBeDirect, willBeForeign,
                       defaultArgIndex);
   }
 
   /// Returns the foreign (or native) entry point corresponding to the same
   /// decl.
   SILDeclRef asForeign(bool foreign = true) const {
-    return SILDeclRef(loc.getOpaqueValue(), kind, uncurryLevel, isCurried,
-                      isDirectReference, foreign, defaultArgIndex);
+    return SILDeclRef(loc.getOpaqueValue(), kind, Expansion, uncurryLevel,
+                      isCurried, isDirectReference, foreign, defaultArgIndex);
   }
 
   SILDeclRef asDirectReference(bool direct = true) const {
@@ -321,22 +317,7 @@ struct SILDeclRef {
   /// True if the decl ref references a thunk from a natively Swift declaration
   /// to foreign C or ObjC calling convention.
   bool isNativeToForeignThunk() const;
-  
-  /// Produces a SILDeclRef from an opaque value.
-  explicit SILDeclRef(void *opaqueLoc,
-                       Kind kind,
-                       unsigned uncurryLevel,
-                       bool isCurried,
-                       bool isDirectReference,
-                       bool isForeign,
-                       unsigned defaultArgIndex)
-    : loc(Loc::getFromOpaqueValue(opaqueLoc)),
-      kind(kind), uncurryLevel(uncurryLevel),
-      isCurried(isCurried),
-      isForeign(isForeign), isDirectReference(isDirectReference),
-      defaultArgIndex(defaultArgIndex)
-  {}
-  
+
   /// Return a SILDeclRef to the declaration overridden by this one, or
   /// a null SILDeclRef if there is no override.
   SILDeclRef getOverridden() const {
@@ -353,7 +334,25 @@ struct SILDeclRef {
   /// overrides. This may be different from "getOverridden" because some
   /// declarations do not always have vtable entries.
   SILDeclRef getOverriddenVTableEntry() const;
-  
+
+private:
+  friend struct llvm::DenseMapInfo<swift::SILDeclRef>;
+  /// Produces a SILDeclRef from an opaque value.
+  explicit SILDeclRef(void *opaqueLoc,
+                       Kind kind,
+                       unsigned rawExpansion,
+                       unsigned uncurryLevel,
+                       bool isCurried,
+                       bool isDirectReference,
+                       bool isForeign,
+                       unsigned defaultArgIndex)
+    : loc(Loc::getFromOpaqueValue(opaqueLoc)),
+      kind(kind), uncurryLevel(uncurryLevel), Expansion(rawExpansion),
+      isCurried(isCurried),
+      isForeign(isForeign), isDirectReference(isDirectReference),
+      defaultArgIndex(defaultArgIndex)
+  {}
+
 };
 
 inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, SILDeclRef C) {
@@ -370,16 +369,17 @@ template<> struct DenseMapInfo<swift::SILDeclRef> {
   using SILDeclRef = swift::SILDeclRef;
   using Kind = SILDeclRef::Kind;
   using Loc = SILDeclRef::Loc;
+  using ResilienceExpansion = swift::ResilienceExpansion;
   using PointerInfo = DenseMapInfo<void*>;
   using UnsignedInfo = DenseMapInfo<unsigned>;
 
   static SILDeclRef getEmptyKey() {
-    return SILDeclRef(PointerInfo::getEmptyKey(), Kind::Func, 0,
-                      false, false, false, 0);
+    return SILDeclRef(PointerInfo::getEmptyKey(), Kind::Func,
+                      0, 0, false, false, false, 0);
   }
   static SILDeclRef getTombstoneKey() {
-    return SILDeclRef(PointerInfo::getTombstoneKey(), Kind::Func, 0,
-                      false, false, false, 0);
+    return SILDeclRef(PointerInfo::getTombstoneKey(), Kind::Func,
+                      0, 0, false, false, false, 0);
   }
   static unsigned getHashValue(swift::SILDeclRef Val) {
     unsigned h1 = PointerInfo::getHashValue(Val.loc.getOpaqueValue());