Serialization of @differentiable attribute.

Author: bgogul

lib/Serialization/ModuleFormat.h

@@ -1734,7 +1734,19 @@ namespace decls_block {
     GenericSignatureIDField // specialized signature
   >;
 
-#define SIMPLE_DECL_ATTR(X, CLASS, ...) \
+  using DifferentiableDeclAttrLayout = BCRecordLayout<
+    Differentiable_DECL_ATTR,
+    BCFixed<1>, // Implicit flag.
+    BCFixed<1>, // Linear flag.
+    IdentifierIDField, // JVP name.
+    DeclIDField, // JVP function declaration.
+    IdentifierIDField, // VJP name.
+    DeclIDField, // VJP function declaration.
+    GenericSignatureIDField, // Derivative generic signature.
+    BCArray<BCFixed<1>> // Differentiation parameter indices' bitvector.
+  >;
+
+#define SIMPLE_DECL_ATTR(X, CLASS, ...)         \
   using CLASS##DeclAttrLayout = BCRecordLayout< \
     CLASS##_DECL_ATTR, \
     BCFixed<1> /* implicit flag */ \

lib/Serialization/Serialization.cpp

@@ -2270,6 +2270,37 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
       break;
     }
 
+    case DAK_Differentiable: {
+      auto abbrCode = S.DeclTypeAbbrCodes[DifferentiableDeclAttrLayout::Code];
+      auto *attr = cast<DifferentiableAttr>(DA);
+
+      IdentifierID jvpName = 0;
+      DeclID jvpRef = 0;
+      if (auto jvp = attr->getJVP())
+        jvpName = S.addDeclBaseNameRef(jvp->Name.getBaseName());
+      if (auto jvpFunction = attr->getJVPFunction())
+        jvpRef = S.addDeclRef(jvpFunction);
+
+      IdentifierID vjpName = 0;
+      DeclID vjpRef = 0;
+      if (auto vjp = attr->getVJP())
+        vjpName = S.addDeclBaseNameRef(vjp->Name.getBaseName());
+      if (auto vjpFunction = attr->getVJPFunction())
+        vjpRef = S.addDeclRef(vjpFunction);
+
+      auto paramIndices = attr->getParameterIndices();
+      assert(paramIndices && "Checked parameter indices must be resolved");
+      SmallVector<bool, 4> indices;
+      for (unsigned i : swift::indices(paramIndices->parameters))
+        indices.push_back(paramIndices->parameters[i]);
+
+      DifferentiableDeclAttrLayout::emitRecord(
+          S.Out, S.ScratchRecord, abbrCode, attr->isImplicit(),
+          attr->isLinear(), jvpName, jvpRef, vjpName, vjpRef,
+          S.addGenericSignatureRef(attr->getDerivativeGenericSignature()),
+          indices);
+      return;
+    }
     }
   }
 

utils/gyb_syntax_support/NodeSerializationCodes.py

@@ -237,14 +237,13 @@
     'LayoutRequirement': 233,
     'LayoutConstraint': 234,
     'OpaqueReturnTypeOfAttributeArguments': 235,
-    'LayoutConstraint': 236,
-    'DifferentiableAttributeArguments': 237,
-    'DifferentiationParamsClause': 238,
-    'DifferentiationParams': 239,
-    'DifferentiationParamList': 240,
-    'DifferentiationParam': 241,
-    'DifferentiableAttributeFuncSpecifier': 242,
-    'FunctionDeclName': 243,
+    'DifferentiableAttributeArguments': 236,
+    'DifferentiationParamsClause': 237,
+    'DifferentiationParams': 238,
+    'DifferentiationParamList': 239,
+    'DifferentiationParam': 240,
+    'DifferentiableAttributeFuncSpecifier': 241,
+    'FunctionDeclName': 242,
 }