[SILGen] Handle indirect error results in allocating class initializers

Author: DougGregor

lib/SILGen/SILGenConstructor.cpp

@@ -936,6 +936,22 @@ void SILGenFunction::emitClassConstructorAllocator(ConstructorDecl *ctor) {
   // Forward the constructor arguments.
   // FIXME: Handle 'self' along with the other body patterns.
   SmallVector<SILValue, 8> args;
+
+  // If the function we're calling has an indirect error result, create an
+  // argument for it.
+  if (F.getConventions().hasIndirectSILErrorResults()) {
+    assert(F.getConventions().getNumIndirectSILErrorResults() == 1);
+    auto paramTy = F.mapTypeIntoContext(
+                       F.getConventions().getSILErrorType(getTypeExpansionContext()));
+    auto inContextParamTy = F.getLoweredType(paramTy.getASTType())
+                                .getCategoryType(paramTy.getCategory());
+    SILArgument *arg = F.begin()->createFunctionArgument(inContextParamTy);
+
+    IndirectErrorResult = arg;
+
+    args.push_back(arg);
+  }
+
   bindParametersForForwarding(ctor->getParameters(), args);
 
   if (ctor->requiresUnavailableDeclABICompatibilityStubs())

lib/SILGen/SILGenPoly.cpp

@@ -897,7 +897,7 @@ void SILGenFunction::collectThunkParams(
 static llvm::Optional<SILValue>
 emitThunkIndirectErrorArgument(SILGenFunction &SGF, SILLocation loc,
                                CanSILFunctionType fnType) {
-  // If the function we're calling has as indirect error result, create an
+  // If the function we're calling has an indirect error result, create an
   // argument for it.
   auto innerError = fnType->getOptionalErrorResult();
   if (!innerError || innerError->getConvention() != ResultConvention::Indirect)
@@ -4876,7 +4876,7 @@ static void buildThunkBody(SILGenFunction &SGF, SILLocation loc,
                      outputSubstType.getResult(),
                      fnType, thunkType);
 
-  // If the function we're calling has as indirect error result, create an
+  // If the function we're calling has an indirect error result, create an
   // argument for it.
   if (auto innerIndirectErrorAddr =
           emitThunkIndirectErrorArgument(SGF, loc, fnType)) {
@@ -6216,7 +6216,7 @@ SILGenFunction::emitVTableThunk(SILDeclRef base,
                         inputSubstType.getResult(),
                         derivedFTy, thunkTy);
 
-    // If the function we're calling has as indirect error result, create an
+    // If the function we're calling has an indirect error result, create an
     // argument for it.
     if (auto innerIndirectErrorAddr =
             emitThunkIndirectErrorArgument(*this, loc, derivedFTy)) {
@@ -6607,7 +6607,7 @@ void SILGenFunction::emitProtocolWitness(
                         reqtSubstTy.getResult(),
                         witnessFTy, thunkTy);
 
-    // If the function we're calling has as indirect error result, create an
+    // If the function we're calling has an indirect error result, create an
     // argument for it.
     if (auto innerIndirectErrorAddr =
             emitThunkIndirectErrorArgument(*this, loc, witnessFTy)) {

test/SILGen/typed_throws.swift

@@ -115,3 +115,15 @@ func throwsConcreteWithDoCatchTypedRethrow() throws(MyError) {
   // CHECK: [[DEFAULT_BB]]:
   // CHECK-NEXT: throw [[ERROR]] : $MyError
 }
+
+open class MyClass {
+  // CHECK-LABEL: sil [serialized] [exact_self_class] [ossa] @$s12typed_throws7MyClassC4bodyACyyxYKXE_txYKcs5ErrorRzlufC : $@convention(method) <E where E : Error> (@guaranteed @noescape @callee_guaranteed @substituted <τ_0_0> () -> @error_indirect τ_0_0 for <E>, @thick MyClass.Type) -> (@owned MyClass, @error_indirect E)
+  // CHECK: bb0(%0 : $*E, %1 : @guaranteed $@noescape @callee_guaranteed @substituted <τ_0_0> () -> @error_indirect τ_0_0 for <E>, %2 : $@thick MyClass.Type):
+  // CHECK: try_apply{{.*}}, normal [[NORMAL_BB:bb[0-9]+]], error [[ERROR_BB:bb[0-9]+]]
+  // CHECK: [[NORMAL_BB]]([[SELF:%.*]] : @owned $MyClass):
+  // CHECK-NEXT: return [[SELF]] : $MyClass
+  // CHECK: [[ERROR_BB]]:
+  // CHECK-NEXT: throw_addr
+  public init<E>(body: () throws(E) -> Void) throws(E) {
+  }
+}