Merge pull request #7854 from slavapestov/small-sil-verifier-fix

SIL: Fix verifier crash with metatypes of dynamic Self

Author: slavapestov

lib/SIL/SILType.cpp

@@ -376,7 +376,6 @@ SILType SILType::getMetatypeInstanceType(SILModule &M) const {
   assert(MetatypeType->is<AnyMetatypeType>() &&
          "This method should only be called on SILTypes with an underlying "
          "metatype type.");
-  assert(isObject() && "Should only be called on object types.");
   Type instanceType =
     MetatypeType->castTo<AnyMetatypeType>()->getInstanceType();
 

lib/SIL/SILVerifier.cpp

@@ -1649,14 +1649,8 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
   }
 
   // Is a SIL type a potential lowering of a formal type?
-  static bool isLoweringOf(SILType loweredType,
-                           CanType formalType) {
-    
-    
-    // Dynamic self has the same lowering as its contained type.
-    if (auto dynamicSelf = dyn_cast<DynamicSelfType>(formalType))
-      formalType = CanType(dynamicSelf->getSelfType());
-
+  bool isLoweringOf(SILType loweredType,
+                    CanType formalType) {
     // Optional lowers its contained type. The difference between Optional
     // and IUO is lowered away.
     SILType loweredObjectType = loweredType
@@ -1672,7 +1666,8 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
     // Metatypes preserve their instance type through lowering.
     if (auto loweredMT = loweredType.getAs<MetatypeType>()) {
       if (auto formalMT = dyn_cast<MetatypeType>(formalType)) {
-        return loweredMT.getInstanceType() == formalMT.getInstanceType();
+        return isLoweringOf(loweredType.getMetatypeInstanceType(F.getModule()),
+                            formalMT.getInstanceType());
       }
     }
     if (auto loweredEMT = loweredType.getAs<ExistentialMetatypeType>()) {
@@ -1701,7 +1696,11 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
         }
         return true;
       }
-    
+
+    // Dynamic self has the same lowering as its contained type.
+    if (auto dynamicSelf = dyn_cast<DynamicSelfType>(formalType))
+      formalType = dynamicSelf.getSelfType();
+
     // Other types are preserved through lowering.
     return loweredType.getSwiftRValueType() == formalType;
   }

test/SILGen/dynamic_self.swift

@@ -249,6 +249,20 @@ func partialApplySelfReturn(c: Factory, t: Factory.Type) {
   _ = Factory.staticNewInstance
 }
 
+class FactoryFactory {
+
+  // CHECK-LABEL: sil hidden @_T012dynamic_self07FactoryC0C11newInstanceACXDyFZ : $@convention(method) (@thick FactoryFactory.Type) -> @owned FactoryFactory
+  static func newInstance() -> Self {
+    // CHECK: bb0(%0 : $@thick FactoryFactory.Type):
+
+    // CHECK: [[METATYPE:%.*]] = value_metatype $@thick @dynamic_self FactoryFactory.Type.Type, %0 : $@thick FactoryFactory.Type
+    // CHECK: [[ANY:%.*]] = init_existential_metatype [[METATYPE]] : $@thick @dynamic_self FactoryFactory.Type.Type, $@thick Any.Type
+    let _: Any.Type = type(of: self)
+
+    // CHECK: unreachable
+  }
+}
+
 // CHECK-LABEL: sil_witness_table hidden X: P module dynamic_self {
 // CHECK: method #P.f!1: {{.*}} : @_T012dynamic_self1XCAA1PAaaDP1f{{[_0-9a-zA-Z]*}}FTW