LF: Revert #7742 (#12354)

Following #12338 which merges the two implementations of the structural record projection introduced by #7740, this PR merges the two implementations of the structural record introduced by #7742. However, this PR does not try to cache the field index as it is done 1- unlike what it is suggested by commit message of #7742, the update has a linear complexity anyway, as it has to copy the whole struct. 2- the compiler does not produce any structural record updates As result the PR is basically a revert of #7742. CHANGELOG_BEGIN CHANGELOG_END
digital-asset · Jan 11, 2022 · 30300fd · 30300fd
1 parent 631aa5c
commit 30300fd
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Showing 4 changed files with 15 additions and 40 deletions.
diff --git a/daml-lf/interpreter/src/main/scala/com/digitalasset/daml/lf/speedy/Compiler.scala b/daml-lf/interpreter/src/main/scala/com/digitalasset/daml/lf/speedy/Compiler.scala
@@ -499,16 +499,8 @@ private[lf] final class Compiler(
         )
       case EStructProj(field, struct) =>
         SBStructProj(field)(compile(env, struct))
-      case structUpd: EStructUpd =>
-        structUpd.fieldIndex match {
-          case None =>
-            SBStructUpdByName(structUpd.field)(
-              compile(env, structUpd.struct),
-              compile(env, structUpd.update),
-            )
-          case Some(index) =>
-            SBStructUpd(index)(compile(env, structUpd.struct), compile(env, structUpd.update))
-        }
+      case EStructUpd(field, struct, update) =>
+        SBStructUpd(field)(compile(env, struct), compile(env, update))
       case ECase(scrut, alts) =>
         compileECase(env, scrut, alts)
       case ENil(_) =>

diff --git a/daml-lf/interpreter/src/main/scala/com/digitalasset/daml/lf/speedy/SBuiltin.scala b/daml-lf/interpreter/src/main/scala/com/digitalasset/daml/lf/speedy/SBuiltin.scala
@@ -779,25 +779,13 @@ private[lf] object SBuiltin {
     }
   }
 
-  /** $tupd[fieldIndex] :: Struct -> a -> Struct */
-  final case class SBStructUpd(fieldIndex: Int) extends SBuiltinPure(2) {
-    override private[speedy] def executePure(args: util.ArrayList[SValue]): SStruct = {
-      val struct = getSStruct(args, 0)
-      val values2 = struct.values.clone.asInstanceOf[util.ArrayList[SValue]]
-      discard(values2.set(fieldIndex, args.get(1)))
-      struct.copy(values = values2)
-    }
-  }
-
   /** $tupd[field] :: Struct -> a -> Struct */
-  // This is a slower version of `SBStructUpd` for the case when we didn't run
-  // the Daml-LF type checker and hence didn't infer the field index.
-  final case class SBStructUpdByName(field: Ast.FieldName) extends SBuiltinPure(2) {
+  final case class SBStructUpd(field: Ast.FieldName) extends SBuiltinPure(2) {
     override private[speedy] def executePure(args: util.ArrayList[SValue]): SStruct = {
       val struct = getSStruct(args, 0)
-      val values2 = struct.values.clone.asInstanceOf[util.ArrayList[SValue]]
-      discard(values2.set(struct.fieldNames.indexOf(field), args.get(1)))
-      struct.copy(values = values2)
+      val values = struct.values.clone.asInstanceOf[util.ArrayList[SValue]]
+      discard(values.set(struct.fieldNames.indexOf(field), args.get(1)))
+      struct.copy(values = values)
     }
   }
 

diff --git a/daml-lf/language/src/main/scala/com/digitalasset/daml/lf/language/Ast.scala b/daml-lf/language/src/main/scala/com/digitalasset/daml/lf/language/Ast.scala
@@ -87,11 +87,8 @@ object Ast {
   /** Struct projection. */
   final case class EStructProj(field: FieldName, struct: Expr) extends Expr
 
-  /** Non-destructive struct update. */
-  final case class EStructUpd(field: FieldName, struct: Expr, update: Expr) extends Expr {
-    // The actual index is filled in by the type checker.
-    private[lf] var fieldIndex: Option[Int] = None
-  }
+  /** Struct update. */
+  final case class EStructUpd(field: FieldName, struct: Expr, update: Expr) extends Expr
 
   /** Expression application. Function can be an abstraction or a builtin function. */
   final case class EApp(fun: Expr, arg: Expr) extends Expr

diff --git a/daml-lf/validation/src/main/scala/com/digitalasset/daml/lf/validation/Typing.scala b/daml-lf/validation/src/main/scala/com/digitalasset/daml/lf/validation/Typing.scala
@@ -650,19 +650,17 @@ private[validation] object Typing {
 
     private def typeOfStructProj(proj: EStructProj): Type =
       toStruct(typeOf(proj.struct)).fields.get(proj.field) match {
-        case Some(value) => value
+        case Some(typ) => typ
         case None => throw EUnknownField(ctx, proj.field)
       }
 
     private def typeOfStructUpd(upd: EStructUpd): Type = {
-      val typ @ TStruct(structType) = toStruct(typeOf(upd.struct))
-      val index = structType.indexOf(upd.field)
-      if (index < 0)
-        throw EUnknownField(ctx, upd.field)
-      else {
-        upd.fieldIndex = Some(index)
-        checkExpr(upd.update, structType.toImmArray(index)._2)
-        typ
+      val structType = toStruct(typeOf(upd.struct))
+      structType.fields.get(upd.field) match {
+        case Some(updateType) =>
+          checkExpr(upd.update, updateType)
+          structType
+        case None => throw EUnknownField(ctx, upd.field)
       }
     }