Merge pull request swiftlang#23618 from slavapestov/array-expr-lowering

Convert ArrayExpr to not use callWitness() or generate a SemanticExpr.

Author: slavapestov

include/swift/AST/Expr.h

@@ -2206,6 +2206,7 @@ class TupleExpr final : public Expr,
 class CollectionExpr : public Expr {
   SourceLoc LBracketLoc;
   SourceLoc RBracketLoc;
+  ConcreteDeclRef Initializer;
 
   Expr *SemanticExpr = nullptr;
 
@@ -2282,6 +2283,14 @@ class CollectionExpr : public Expr {
            e->getKind() <= ExprKind::Last_CollectionExpr;
   }
 
+  /// Retrieve the initializer that will be used to construct the 'array'
+  /// literal from the result of the initializer.
+  ConcreteDeclRef getInitializer() const { return Initializer; }
+
+  /// Set the initializer that will be used to construct the 'array' literal.
+  void setInitializer(ConcreteDeclRef initializer) {
+    Initializer = initializer;
+  }
 };
 
 /// An array literal expression [a, b, c].
@@ -2312,6 +2321,8 @@ class ArrayExpr final : public CollectionExpr,
   static bool classof(const Expr *e) {
     return e->getKind() == ExprKind::Array;
   }
+
+  Type getElementType();
 };
 
 /// A dictionary literal expression [a : x, b : y, c : z].

lib/AST/ASTDumper.cpp

@@ -2068,6 +2068,8 @@ class PrintExpr : public ExprVisitor<PrintExpr> {
   }
   void visitArrayExpr(ArrayExpr *E) {
     printCommon(E, "array_expr");
+    PrintWithColorRAII(OS, LiteralValueColor) << " initializer=";
+    E->getInitializer().dump(PrintWithColorRAII(OS, LiteralValueColor).getOS());
     for (auto elt : E->getElements()) {
       OS << '\n';
       printRec(elt);

lib/AST/Expr.cpp

@@ -1489,6 +1489,19 @@ ArrayExpr *ArrayExpr::create(ASTContext &C, SourceLoc LBracketLoc,
   return new (Mem) ArrayExpr(LBracketLoc, Elements, CommaLocs, RBracketLoc, Ty);
 }
 
+Type ArrayExpr::getElementType() {
+  auto init = getInitializer();
+  if (!init)
+    return Type();
+
+  auto *decl = cast<ConstructorDecl>(init.getDecl());
+  return decl->getMethodInterfaceType()
+      ->getAs<AnyFunctionType>()
+      ->getParams()[0]
+      .getPlainType()
+      .subst(init.getSubstitutions());
+}
+
 DictionaryExpr *DictionaryExpr::create(ASTContext &C, SourceLoc LBracketLoc,
                              ArrayRef<Expr*> Elements,
                              ArrayRef<SourceLoc> CommaLocs,

lib/IDE/ExprContextAnalysis.cpp

@@ -588,6 +588,12 @@ class ExprContextAnalyzer {
       analyzeApplyExpr(Parent);
       break;
     }
+    case ExprKind::Array: {
+      if (auto type = ParsedExpr->getType()) {
+        recordPossibleType(type);
+      }
+      break;
+    }
     case ExprKind::Assign: {
       auto *AE = cast<AssignExpr>(Parent);
 
@@ -744,6 +750,7 @@ class ExprContextAnalyzer {
         case ExprKind::PrefixUnary:
         case ExprKind::Assign:
         case ExprKind::Subscript:
+        case ExprKind::Array:
           return true;
         case ExprKind::Tuple: {
           auto ParentE = Parent.getAsExpr();

lib/SILGen/RValue.h

@@ -308,42 +308,6 @@ class RValue {
   /// be returned. Otherwise, an object will be returned. So this is a
   /// convenient way to determine if an RValue needs an address.
   SILType getLoweredImplodedTupleType(SILGenFunction &SGF) const &;
-
-  /// Rewrite the type of this r-value.
-  void rewriteType(CanType newType) & {
-#ifndef NDEBUG
-    static const auto areSimilarTypes = [](CanType l, CanType r) {
-      if (l == r) return true;
-
-      // Allow function types to disagree about 'noescape'.
-      if (auto lf = dyn_cast<FunctionType>(l)) {
-        if (auto rf = dyn_cast<FunctionType>(r)) {
-          auto lParams = lf.getParams();
-          auto rParams = rf.getParams();
-          return AnyFunctionType::equalParams(lParams, rParams) &&
-                 lf.getResult() == rf.getResult() &&
-                 lf->getExtInfo().withNoEscape(false) ==
-                     rf->getExtInfo().withNoEscape(false);
-        }
-      }
-      return false;
-    };
-
-    static const auto isSingleElementTuple = [](CanType type, CanType eltType) {
-      if (auto tupleType = dyn_cast<TupleType>(type)) {
-        return tupleType->getNumElements() == 1 &&
-               areSimilarTypes(tupleType.getElementType(0), eltType);
-      }
-      return false;
-    };
-
-    // We only allow a very modest set of changes to a type.
-    assert(areSimilarTypes(newType, type) ||
-           isSingleElementTuple(newType, type) ||
-           isSingleElementTuple(type, newType));
-#endif
-    type = newType;
-  }
 
   /// Emit an equivalent value with independent ownership.
   RValue copy(SILGenFunction &SGF, SILLocation loc) const &;

lib/SILGen/SILGenApply.cpp

@@ -5635,20 +5635,7 @@ RValue SILGenFunction::emitLiteral(LiteralExpr *literal, SGFContext C) {
     }
   }
 
-  // Helper routine to add an argument label if we need one.
-  auto relabelArgument = [&](ConcreteDeclRef callee, RValue &arg) {
-    auto name = callee.getDecl()->getFullName();
-    auto argLabels = name.getArgumentNames();
-    if (argLabels.size() == 1 && !argLabels[0].empty() &&
-        !isa<TupleType>(arg.getType())) {
-      Type newType = TupleType::get({TupleTypeElt(arg.getType(), argLabels[0])},
-                                    getASTContext());
-      arg.rewriteType(newType->getCanonicalType());
-    }
-  };
-
   // Call the builtin initializer.
-  relabelArgument(builtinInit, builtinLiteralArgs);
   RValue builtinLiteral =
     emitApplyAllocatingInitializer(literal, builtinInit,
                                    std::move(builtinLiteralArgs),
@@ -5659,7 +5646,6 @@ RValue SILGenFunction::emitLiteral(LiteralExpr *literal, SGFContext C) {
   if (!init) return builtinLiteral;
 
   // Otherwise, perform the second initialization step.
-  relabelArgument(init, builtinLiteral);
   RValue result = emitApplyAllocatingInitializer(literal, init,
                                                  std::move(builtinLiteral),
                                                  literal->getType(), C);
@@ -6189,14 +6175,9 @@ void SILGenFunction::emitSetAccessor(SILLocation loc, SILDeclRef set,
   values.addArbitrary(std::move(setValue));
 
   if (!subscriptIndices.isNull()) {
-    unsigned paramIndex = 1;
     for (auto &component : std::move(subscriptIndices).getSources()) {
-      auto param = accessType.getParams()[paramIndex++];
-      auto paramType = param.getParameterType();
-
       auto argLoc = component.getKnownRValueLocation();
       RValue &&arg = std::move(component).asKnownRValue(*this);
-      arg.rewriteType(paramType);
       values.add(argLoc, std::move(arg));
     }
   }

lib/SILGen/SILGenExpr.cpp

@@ -462,7 +462,8 @@ namespace {
     RValue visitKeyPathExpr(KeyPathExpr *E, SGFContext C);
     RValue visitMagicIdentifierLiteralExpr(MagicIdentifierLiteralExpr *E,
                                            SGFContext C);
-    RValue visitCollectionExpr(CollectionExpr *E, SGFContext C);
+    RValue visitArrayExpr(ArrayExpr *E, SGFContext C);
+    RValue visitDictionaryExpr(DictionaryExpr *E, SGFContext C);
     RValue visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *E,
                                             SGFContext C);
     RValue visitInjectIntoOptionalExpr(InjectIntoOptionalExpr *E, SGFContext C);
@@ -3601,7 +3602,64 @@ visitMagicIdentifierLiteralExpr(MagicIdentifierLiteralExpr *E, SGFContext C) {
   llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
 }
 
-RValue RValueEmitter::visitCollectionExpr(CollectionExpr *E, SGFContext C) {
+RValue RValueEmitter::visitArrayExpr(ArrayExpr *E, SGFContext C) {
+  auto loc = SILLocation(E);
+  ArgumentScope scope(SGF, loc);
+
+  CanType elementType = E->getElementType()->getCanonicalType();
+  CanType arrayTy = ArraySliceType::get(elementType)->getCanonicalType();
+  VarargsInfo varargsInfo =
+      emitBeginVarargs(SGF, loc, elementType, arrayTy,
+                       E->getNumElements(), {});
+
+  // Cleanups for any elements that have been initialized so far.
+  SmallVector<CleanupHandle, 8> cleanups;
+
+  for (unsigned index : range(E->getNumElements())) {
+    auto destAddr = varargsInfo.getBaseAddress();
+    if (index != 0) {
+      SILValue indexValue = SGF.B.createIntegerLiteral(
+          loc, SILType::getBuiltinWordType(SGF.getASTContext()), index);
+      destAddr = SGF.B.createIndexAddr(loc, destAddr, indexValue);
+    }
+    auto &destTL = varargsInfo.getBaseTypeLowering();
+    // Create a dormant cleanup for the value in case we exit before the
+    // full array has been constructed.
+
+    CleanupHandle destCleanup = CleanupHandle::invalid();
+    if (!destTL.isTrivial()) {
+      destCleanup = SGF.enterDestroyCleanup(destAddr);
+      SGF.Cleanups.setCleanupState(destCleanup, CleanupState::Dormant);
+      cleanups.push_back(destCleanup);
+    }
+
+    TemporaryInitialization init(destAddr, destCleanup);
+
+    ArgumentSource(E->getElements()[index])
+        .forwardInto(SGF, varargsInfo.getBaseAbstractionPattern(), &init,
+                     destTL);
+  }
+
+  // Kill the per-element cleanups. The array will take ownership of them.
+  for (auto destCleanup : cleanups)
+    SGF.Cleanups.setCleanupState(destCleanup, CleanupState::Dead);
+
+  RValue arg(SGF, loc, arrayTy,
+             emitEndVarargs(SGF, loc, std::move(varargsInfo)));
+
+  arg = scope.popPreservingValue(std::move(arg));
+
+  // If we're building an array, we don't have to call the initializer;
+  // we've already built one.
+  if (arrayTy->isEqual(E->getType()))
+    return arg;
+
+  // Call the builtin initializer.
+  return SGF.emitApplyAllocatingInitializer(
+      loc, E->getInitializer(), std::move(arg), E->getType(), C);
+}
+
+RValue RValueEmitter::visitDictionaryExpr(DictionaryExpr *E, SGFContext C) {
   return visit(E->getSemanticExpr(), C);
 }
 

lib/Sema/CSApply.cpp

@@ -2782,71 +2782,23 @@ namespace {
                               ConformanceCheckFlags::InExpression);
       assert(conformance && "Type does not conform to protocol?");
 
-      // Call the witness that builds the array literal.
-      // FIXME: callWitness() may end up re-doing some work we already did
-      // to convert the array literal elements to the element type. It would
-      // be nicer to re-use them.
-
-      // FIXME: This location info is bogus.
-      Expr *typeRef = TypeExpr::createImplicitHack(expr->getLoc(), arrayTy,
-                                                   tc.Context);
-      cs.cacheExprTypes(typeRef);
-
       DeclName name(tc.Context, DeclBaseName::createConstructor(),
                     { tc.Context.Id_arrayLiteral });
 
-      // Coerce the array elements to be rvalues, so that other type-checker
-      // code that attempts to peephole the AST doesn't have to re-load the
-      // elements (and break the invariant that lvalue nodes only get their
-      // access kind set once).
-      for (auto &element : expr->getElements()) {
-        element = cs.coerceToRValue(element);
-      }
-
-      // Restructure the argument to provide the appropriate labels in the
-      // tuple.
-      SmallVector<TupleTypeElt, 4> typeElements;
-      SmallVector<Identifier, 4> names;
-      bool first = true;
-      for (auto elt : expr->getElements()) {
-        if (first) {
-          typeElements.push_back(TupleTypeElt(cs.getType(elt),
-                                              tc.Context.Id_arrayLiteral));
-          names.push_back(tc.Context.Id_arrayLiteral);
+      ConcreteDeclRef witness =
+          findNamedWitnessImpl(tc, dc, arrayTy->getRValueType(), arrayProto,
+                               name, diag::array_protocol_broken, conformance);
+      if (!witness || !isa<AbstractFunctionDecl>(witness.getDecl()))
+        return nullptr;
+      expr->setInitializer(witness);
 
-          first = false;
-          continue;
-        }
+      auto elementType = expr->getElementType();
 
-        typeElements.push_back(cs.getType(elt));
-        names.push_back(Identifier());
+      for (auto &element : expr->getElements()) {
+        element = coerceToType(element, elementType,
+                               cs.getConstraintLocator(element));
       }
 
-      Type argType = TupleType::get(typeElements, tc.Context);
-      assert(isa<TupleType>(argType.getPointer()));
-
-      Expr *arg =
-        TupleExpr::create(tc.Context, SourceLoc(),
-                          expr->getElements(),
-                          names,
-                          { },
-                          SourceLoc(), /*HasTrailingClosure=*/false,
-                          /*Implicit=*/true,
-                          argType);
-
-      cs.cacheExprTypes(arg);
-
-      cs.setExprTypes(typeRef);
-      cs.setExprTypes(arg);
-
-      Expr *result = tc.callWitness(typeRef, dc, arrayProto, *conformance,
-                                    name, arg, diag::array_protocol_broken);
-      if (!result)
-        return nullptr;
-
-      cs.cacheExprTypes(result);
-
-      expr->setSemanticExpr(result);
       return expr;
     }
 

test/IDE/complete_unresolved_members.swift

@@ -368,12 +368,12 @@ func f() -> SomeEnum1 {
   return .#^UNRESOLVED_27^#
 }
 
-let TopLevelVar1 = OptionSetTaker7([.#^UNRESOLVED_28^#], Op2: [.Option4])
+let TopLevelVar1 = OptionSetTaker7([.#^UNRESOLVED_28^#], [.Option4])
 
 let TopLevelVar2 = OptionSetTaker1([.#^UNRESOLVED_29^#])
 
-let TopLevelVar3 = OptionSetTaker7([.Option1], Op2: [.#^UNRESOLVED_30^#])
-let TopLevelVar4 = OptionSetTaker7([.Option1], Op2: [.Option4, .#^UNRESOLVED_31^#])
+let TopLevelVar3 = OptionSetTaker7([.Option1], [.#^UNRESOLVED_30^#])
+let TopLevelVar4 = OptionSetTaker7([.Option1], [.Option4, .#^UNRESOLVED_31^#])
 
 let _: [SomeEnum1] = [.#^UNRESOLVED_32^#]
 let _: [SomeEnum1] = [.South, .#^UNRESOLVED_33^#]

test/Interpreter/arrays.swift

@@ -161,3 +161,25 @@ test()
 let mdaPerf = [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]]
 print(mdaPerf)
 // CHECK: {{\[}}[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]]
+
+class Deinitable {
+  deinit {
+    print("deinit called")
+  }
+}
+
+enum E : Error {
+  case error
+}
+
+func throwingFunc() throws -> Deinitable {
+  throw E.error
+}
+
+do {
+  let array = try [Deinitable(), throwingFunc()]
+} catch {
+  // CHECK: deinit called
+  // CHECK: error thrown
+  print("error thrown")
+}