[Autodiff upstream] Finishing @transpose attr serialization (swiftlang#30683)

* Adding @transpose attr deserialization support

* Turning on the transpose serialization test

Author: ematejska

lib/Serialization/Deserialization.cpp

@@ -4369,6 +4369,30 @@ llvm::Error DeclDeserializer::deserializeDeclAttributes() {
         break;
       }
 
+      case decls_block::Transpose_DECL_ATTR: {
+        bool isImplicit;
+        uint64_t origNameId;
+        DeclID origDeclId;
+        ArrayRef<uint64_t> parameters;
+
+        serialization::decls_block::TransposeDeclAttrLayout::readRecord(
+            scratch, isImplicit, origNameId, origDeclId, parameters);
+
+        DeclNameRefWithLoc origName{
+            DeclNameRef(MF.getDeclBaseName(origNameId)), DeclNameLoc()};
+        auto *origDecl = cast<AbstractFunctionDecl>(MF.getDecl(origDeclId));
+        llvm::SmallBitVector parametersBitVector(parameters.size());
+        for (unsigned i : indices(parameters))
+          parametersBitVector[i] = parameters[i];
+        auto *indices = IndexSubset::get(ctx, parametersBitVector);
+        auto *transposeAttr =
+            TransposeAttr::create(ctx, isImplicit, SourceLoc(), SourceRange(),
+                                  /*baseTypeRepr*/ nullptr, origName, indices);
+        transposeAttr->setOriginalFunction(origDecl);
+        Attr = transposeAttr;
+        break;
+      }
+
       case decls_block::SPIAccessControl_DECL_ATTR: {
         ArrayRef<uint64_t> spiIds;
         serialization::decls_block::SPIAccessControlDeclAttrLayout::readRecord(

test/AutoDiff/Serialization/transpose_attr.swift

@@ -5,10 +5,6 @@
 
 // BCANALYZER-NOT: UnknownCode
 
-// TODO(TF-838): Enable this test.
-// Blocked by TF-830: `@transpose` attribute type-checking.
-// XFAIL: *
-
 import _Differentiation
 
 // Dummy `Differentiable`-conforming type.
@@ -50,14 +46,14 @@ extension S {
 
   // CHECK: @transpose(of: instanceMethod, wrt: 0)
   @transpose(of: instanceMethod, wrt: 0)
-  func transposeInstanceMethod(v: S) -> (S, S) {
-    (v, v)
+  func transposeInstanceMethod(t: S) -> S {
+    self + t
   }
 
   // CHECK: @transpose(of: instanceMethod, wrt: self)
   @transpose(of: instanceMethod, wrt: self)
-  func transposeInstanceMethodWrtSelf(v: S) -> (S, S) {
-    (v, v)
+  static func transposeInstanceMethodWrtSelf(_ other: S, t: S) -> S {
+    other + t
   }
 }
 
@@ -70,8 +66,8 @@ extension S {
 
   // CHECK: @transpose(of: staticMethod, wrt: 0)
   @transpose(of: staticMethod, wrt: 0)
-  func transposeStaticMethod(_: S.Type) -> S {
-    self
+  static func transposeStaticMethod(t: S) -> S {
+    t
   }
 }
 
@@ -81,8 +77,8 @@ extension S {
 
   // CHECK: @transpose(of: computedProperty, wrt: self)
   @transpose(of: computedProperty, wrt: self)
-  func transposeProperty() -> Self {
-    self
+  static func transposeProperty(t: Self) -> Self {
+    t
   }
 }
 
@@ -92,7 +88,7 @@ extension S {
 
   // CHECK: @transpose(of: subscript, wrt: self)
   @transpose(of: subscript(_:), wrt: self)
-  func transposeSubscript<T: Differentiable>(x: T) -> Self {
-    self
+  static func transposeSubscript<T: Differentiable>(x: T, t: Self) -> Self {
+    t
   }
 }