[5.9] A few SILGen fixes for variadic generics

include/swift/SIL/AbstractionPatternGenerators.h

@@ -291,6 +291,22 @@ class TupleElementGenerator {
     }
   }
 
+  /// Like `getSubstTypes`, but uses a different and possibly
+  /// non-canonical tuple type.
+  TupleEltTypeArrayRef getSubstTypes(Type ncSubstType) const {
+    assert(!isFinished());
+    if (!origTupleVanishes) {
+      return ncSubstType->castTo<TupleType>()
+               ->getElementTypes().slice(substEltIndex,
+                                         numSubstEltsForOrigElt);
+    } else if (numSubstEltsForOrigElt == 0) {
+      return TupleEltTypeArrayRef();
+    } else {
+      scratchSubstElt = TupleTypeElt(ncSubstType);
+      return TupleEltTypeArrayRef(scratchSubstElt);
+    }
+  }
+
   /// Call this to finalize the traversal and assert that it was done
   /// properly.
   void finish() {

lib/SIL/IR/AbstractionPattern.cpp

@@ -2064,6 +2064,9 @@ class SubstFunctionTypePatternVisitor
     if (auto gp = handleTypeParameter(pattern, t, level))
       return gp;
 
+    if (pattern.isTuple())
+      return visitTuplePattern(t, pattern);
+
     return CanTypeVisitor::visit(t, pattern);
   }
 
@@ -2312,11 +2315,15 @@ class SubstFunctionTypePatternVisitor
         TC.Context, ppt->getBaseType(), substArgs));
   }
 
-  CanType visitTupleType(CanTupleType tuple, AbstractionPattern pattern) {
+  /// Visit a tuple pattern.  Note that, because of vanishing tuples,
+  /// we can't handle this case by matching a tuple type in the
+  /// substituted type; we have to check for a tuple pattern in the
+  /// top-level visit routine.
+  CanType visitTuplePattern(CanType substType, AbstractionPattern pattern) {
     assert(pattern.isTuple());
 
     SmallVector<TupleTypeElt, 4> tupleElts;
-    pattern.forEachTupleElement(tuple, [&](TupleElementGenerator &elt) {
+    pattern.forEachTupleElement(substType, [&](TupleElementGenerator &elt) {
       auto substEltTypes = elt.getSubstTypes();
       CanType eltTy;
       if (!elt.isOrigPackExpansion()) {

lib/SIL/IR/SILType.cpp

@@ -851,6 +851,16 @@ bool SILType::isLoweringOf(TypeExpansionContext context, SILModule &Mod,
     }
   }
 
+  // The pattern of a pack expansion is lowered.
+  if (auto formalExpansion = dyn_cast<PackExpansionType>(formalType)) {
+    if (auto loweredExpansion = loweredType.getAs<PackExpansionType>()) {
+      return loweredExpansion.getCountType() == formalExpansion.getCountType()
+         && SILType::getPrimitiveAddressType(loweredExpansion.getPatternType())
+               .isLoweringOf(context, Mod, formalExpansion.getPatternType());
+    }
+    return false;
+  }
+
   // Dynamic self has the same lowering as its contained type.
   if (auto dynamicSelf = dyn_cast<DynamicSelfType>(formalType))
     formalType = dynamicSelf.getSelfType();

lib/SILGen/RValue.cpp

@@ -94,12 +94,8 @@ class ExplodeTupleValue
 
   void visitType(CanType formalType, ManagedValue v) {
     // If we have a loadable type that has not been loaded, actually load it.
-    if (!v.getType().isObject() && v.getType().isLoadable(SGF.F)) {
-      if (v.isPlusOne(SGF)) {
-        v = SGF.B.createLoadTake(loc, v);
-      } else {
-        v = SGF.B.createLoadBorrow(loc, v);
-      }
+    if (!v.getType().isObject()) {
+      v = SGF.B.createLoadIfLoadable(loc, v);
     }
 
     values.push_back(v);

lib/SILGen/SILGenBuilder.cpp

@@ -437,6 +437,23 @@ ManagedValue SILGenBuilder::createUncheckedTakeEnumDataAddr(
   return cloner.clone(result);
 }
 
+ManagedValue
+SILGenBuilder::createLoadIfLoadable(SILLocation loc, ManagedValue addr) {
+  assert(addr.getType().isAddress());
+  if (!addr.getType().isLoadable(SGF.F))
+    return addr;
+  return createLoadWithSameOwnership(loc, addr);
+}
+
+ManagedValue
+SILGenBuilder::createLoadWithSameOwnership(SILLocation loc,
+                                           ManagedValue addr) {
+  if (addr.isPlusOne(SGF))
+    return createLoadTake(loc, addr);
+  else
+    return createLoadBorrow(loc, addr);
+}
+
 ManagedValue SILGenBuilder::createLoadTake(SILLocation loc, ManagedValue v) {
   auto &lowering = SGF.getTypeLowering(v.getType());
   return createLoadTake(loc, v, lowering);

lib/SILGen/SILGenBuilder.h

@@ -236,6 +236,15 @@ class SILGenBuilder : public SILBuilder {
   ManagedValue createUncheckedTakeEnumDataAddr(SILLocation loc, ManagedValue operand,
                                                EnumElementDecl *element, SILType ty);
 
+  /// Given the address of a value, load a scalar value from it if the type
+  /// is loadable.  Most general routines in SILGen expect to work with
+  /// values with the canonical scalar-ness for their type.
+  ManagedValue createLoadIfLoadable(SILLocation loc, ManagedValue addr);
+
+  /// Given the address of a loadable value, load the value but don't
+  /// change the ownership.
+  ManagedValue createLoadWithSameOwnership(SILLocation loc, ManagedValue addr);
+
   ManagedValue createLoadTake(SILLocation loc, ManagedValue addr);
   ManagedValue createLoadTake(SILLocation loc, ManagedValue addr,
                               const TypeLowering &lowering);

lib/SILGen/SILGenConstructor.cpp

@@ -222,6 +222,7 @@ static RValue emitImplicitValueConstructorArg(SILGenFunction &SGF,
         auto eltAddr =
           SGF.B.createPackElementGet(loc, packIndex, arg, eltTy);
         ManagedValue eltMV = emitManagedParameter(SGF, eltAddr, argIsConsumed);
+        eltMV = SGF.B.createLoadIfLoadable(loc, eltMV);
         eltInit->copyOrInitValueInto(SGF, loc, eltMV, argIsConsumed);
         eltInit->finishInitialization(SGF);
       });
@@ -232,21 +233,18 @@ static RValue emitImplicitValueConstructorArg(SILGenFunction &SGF,
 
   ManagedValue mvArg = emitManagedParameter(SGF, arg, argIsConsumed);
 
+  // This can happen if the value is resilient in the calling convention
+  // but not resilient locally.
+  if (argType.isAddress()) {
+    mvArg = SGF.B.createLoadIfLoadable(loc, mvArg);
+  }
+
   if (argInit) {
     argInit->copyOrInitValueInto(SGF, loc, mvArg, argIsConsumed);
     argInit->finishInitialization(SGF);
     return RValue::forInContext();
   }
 
-  // This can happen if the value is resilient in the calling convention
-  // but not resilient locally.
-  if (argType.isLoadable(SGF.F) && argType.isAddress()) {
-    if (mvArg.isPlusOne(SGF))
-      mvArg = SGF.B.createLoadTake(loc, mvArg);
-    else
-      mvArg = SGF.B.createLoadBorrow(loc, mvArg);
-  }
-
   return RValue(SGF, loc, type, mvArg);
 }
 

lib/SILGen/SILGenProlog.cpp

@@ -263,10 +263,7 @@ class EmitBBArguments : public CanTypeVisitor<EmitBBArguments,
     bool argIsLoadable = argType.isLoadable(SGF.F);
     if (argIsLoadable) {
       if (argType.isAddress()) {
-        if (mv.isPlusOne(SGF))
-          mv = SGF.B.createLoadTake(loc, mv);
-        else
-          mv = SGF.B.createLoadBorrow(loc, mv);
+        mv = SGF.B.createLoadWithSameOwnership(loc, mv);
         argType = argType.getObjectType();
       }
     }
@@ -1569,54 +1566,91 @@ SILValue SILGenFunction::emitGetCurrentExecutor(SILLocation loc) {
   return ExpectedExecutor;
 }
 
+static void emitIndirectPackParameter(SILGenFunction &SGF,
+                                      PackType *resultType,
+                                      CanTupleEltTypeArrayRef
+                                        resultTypesInContext,
+                                      AbstractionPattern origExpansionType,
+                                      DeclContext *DC) {
+  auto &ctx = SGF.getASTContext();
+
+  bool indirect =
+    origExpansionType.arePackElementsPassedIndirectly(SGF.SGM.Types);
+  SmallVector<CanType, 4> packElts;
+  for (auto substEltType : resultTypesInContext) {
+    auto origComponentType
+      = origExpansionType.getPackExpansionComponentType(substEltType);
+    CanType loweredEltTy =
+      SGF.getLoweredRValueType(origComponentType, substEltType);
+    packElts.push_back(loweredEltTy);
+  }
+
+  SILPackType::ExtInfo extInfo(indirect);
+  auto packType = SILPackType::get(ctx, extInfo, packElts);
+  auto resultSILType = SILType::getPrimitiveAddressType(packType);
+
+  auto var = new (ctx) ParamDecl(SourceLoc(), SourceLoc(),
+                                 ctx.getIdentifier("$return_value"), SourceLoc(),
+                                 ctx.getIdentifier("$return_value"),
+                                 DC);
+  var->setSpecifier(ParamSpecifier::InOut);
+  var->setInterfaceType(resultType);
+  auto *arg = SGF.F.begin()->createFunctionArgument(resultSILType, var);
+  (void)arg;
+}
+
 static void emitIndirectResultParameters(SILGenFunction &SGF,
                                          Type resultType,
                                          AbstractionPattern origResultType,
                                          DeclContext *DC) {
-  // Expand tuples.
+  CanType resultTypeInContext =
+    DC->mapTypeIntoContext(resultType)->getCanonicalType();
+
+  // Tuples in the original result type are expanded.
   if (origResultType.isTuple()) {
-    auto tupleType = resultType->castTo<TupleType>();
-    for (unsigned i = 0, e = origResultType.getNumTupleElements(); i < e; ++i) {
-      emitIndirectResultParameters(SGF, tupleType->getElementType(i),
-                                   origResultType.getTupleElementType(i),
-                                   DC);
-    }
+    origResultType.forEachTupleElement(resultTypeInContext,
+                                       [&](TupleElementGenerator &elt) {
+      auto origEltType = elt.getOrigType();
+      auto substEltTypes = elt.getSubstTypes(resultType);
+
+      // If the original element isn't a pack expansion, pull out the
+      // corresponding substituted tuple element and recurse.
+      if (!elt.isOrigPackExpansion()) {
+        emitIndirectResultParameters(SGF, substEltTypes[0], origEltType, DC);
+        return;
+      }
+
+      // Otherwise, bind a pack parameter.
+      PackType *resultPackType = [&] {
+        SmallVector<Type, 4> packElts(substEltTypes.begin(),
+                                      substEltTypes.end());
+        return PackType::get(SGF.getASTContext(), packElts);
+      }();
+      emitIndirectPackParameter(SGF, resultPackType, elt.getSubstTypes(),
+                                origEltType, DC);
+    });
     return;
   }
 
+  assert(!resultType->is<PackExpansionType>());
+
   // If the return type is address-only, emit the indirect return argument.
   auto &resultTI =
-    SGF.SGM.Types.getTypeLowering(origResultType,
-                                  DC->mapTypeIntoContext(resultType),
+    SGF.SGM.Types.getTypeLowering(origResultType, resultTypeInContext,
                                   SGF.getTypeExpansionContext());
 
   // The calling convention always uses minimal resilience expansion.
   auto &resultTIConv = SGF.SGM.Types.getTypeLowering(
-      DC->mapTypeIntoContext(resultType), TypeExpansionContext::minimal());
+      resultTypeInContext, TypeExpansionContext::minimal());
   auto resultConvType = resultTIConv.getLoweredType();
 
   auto &ctx = SGF.getASTContext();
 
   SILType resultSILType = resultTI.getLoweredType().getAddressType();
 
-  // FIXME: respect susbtitution properly and collect the appropriate
-  // tuple components from resultType that correspond to the
-  // pack expansion in origType.
-  bool isPackExpansion = resultType->is<PackExpansionType>();
-  if (isPackExpansion) {
-    resultType = PackType::get(ctx, {resultType});
-
-    bool indirect =
-      origResultType.arePackElementsPassedIndirectly(SGF.SGM.Types);
-    SILPackType::ExtInfo extInfo(indirect);
-    resultSILType = SILType::getPrimitiveAddressType(
-      SILPackType::get(ctx, extInfo, {resultSILType.getASTType()}));
-  }
-
   // And the abstraction pattern may force an indirect return even if the
   // concrete type wouldn't normally be returned indirectly.
-  if (!isPackExpansion &&
-      !SILModuleConventions::isReturnedIndirectlyInSIL(resultConvType,
+  if (!SILModuleConventions::isReturnedIndirectlyInSIL(resultConvType,
                                                        SGF.SGM.M)) {
     if (!SILModuleConventions(SGF.SGM.M).useLoweredAddresses()
         || origResultType.getResultConvention(SGF.SGM.Types) != AbstractionPattern::Indirect)

lib/SILGen/SILGenStmt.cpp

@@ -580,11 +580,29 @@ prepareIndirectResultInit(SILGenFunction &SGF, SILLocation loc,
                           SmallVectorImpl<CleanupHandle> &cleanups) {
   // Recursively decompose tuple abstraction patterns.
   if (origResultType.isTuple()) {
-    auto resultTupleType = cast<TupleType>(resultType);
-    auto tupleInit = new TupleInitialization(resultTupleType);
-    tupleInit->SubInitializations.reserve(resultTupleType->getNumElements());
+    // Normally, we build a compound initialization for the tuple.  But
+    // the initialization we build should match the substituted type,
+    // so if the tuple in the abstraction pattern vanishes under variadic
+    // substitution, we actually just want to return the initializer
+    // for the surviving component.
+    TupleInitialization *tupleInit = nullptr;
+    SmallVector<InitializationPtr, 1> singletonEltInit;
+
+    bool vanishes =
+      origResultType.getVanishingTupleElementPatternType().hasValue();
+    if (!vanishes) {
+      auto resultTupleType = cast<TupleType>(resultType);
+      tupleInit = new TupleInitialization(resultTupleType);
+      tupleInit->SubInitializations.reserve(
+        cast<TupleType>(resultType)->getNumElements());
+    }
+
+    // The list of element initializers to build into.
+    auto &eltInits = (vanishes
+        ? static_cast<SmallVectorImpl<InitializationPtr> &>(singletonEltInit)
+        : tupleInit->SubInitializations);
 
-    origResultType.forEachTupleElement(resultTupleType,
+    origResultType.forEachTupleElement(resultType,
                                        [&](TupleElementGenerator &elt) {
       if (!elt.isOrigPackExpansion()) {
         auto eltInit = prepareIndirectResultInit(SGF, loc, fnTypeForResults,
@@ -594,7 +612,7 @@ prepareIndirectResultInit(SILGenFunction &SGF, SILLocation loc,
                                                  directResults,
                                                  indirectResultAddrs,
                                                  cleanups);
-        tupleInit->SubInitializations.push_back(std::move(eltInit));
+        eltInits.push_back(std::move(eltInit));
       } else {
         assert(allResults[0].isPack());
         assert(SGF.silConv.isSILIndirect(allResults[0]));
@@ -604,11 +622,17 @@ prepareIndirectResultInit(SILGenFunction &SGF, SILLocation loc,
         indirectResultAddrs = indirectResultAddrs.slice(1);
 
         preparePackResultInit(SGF, loc, elt.getOrigType(), elt.getSubstTypes(),
-                              packAddr,
-                              cleanups, tupleInit->SubInitializations);
+                              packAddr, cleanups, eltInits);
       }
     });
 
+    if (vanishes) {
+      assert(singletonEltInit.size() == 1);
+      return std::move(singletonEltInit.front());
+    }
+
+    assert(tupleInit);
+    assert(eltInits.size() == cast<TupleType>(resultType)->getNumElements());
     return InitializationPtr(tupleInit);
   }
 

test/SILGen/variadic-generic-closures.swift

@@ -12,3 +12,12 @@ public struct UsesG<each Input> {
   public init<E>(builder: (repeat G<each Input>) -> E) {}
 }
 UsesG<Int, String, Bool> { a, b, c in 0 }
+
+// rdar://107367324
+func returnVariadicClosure<each T, R>(f: @escaping (repeat each T) -> R) -> (repeat each T) -> R {
+    { (t: repeat each T) -> R in
+        let tuple = (repeat each t)
+        print(tuple)
+        return f(repeat each t)
+    }
+}