Further restrict MetatypeInst constant folding to only apply to types defined in the current module

Author: kubamracek

SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift

@@ -464,12 +464,17 @@ extension Instruction {
       return context.canMakeStaticObjectReadOnly(objectType: gvi.type)
 
     // Metatypes (and upcasts of them to existentials) can be used as static initializers for SE-0492, as long as they
-    // are not generic or resilient
+    // are:
+    // (1) not a generic type
+    // (2) not a resilient type
+    // (3) not a resilient conformance
+    // (4) a type defined in the currently compiled module
     case let mti as MetatypeInst:
       if !mti.type.isGenericAtAnyLevel,
         let nominal = mti.type.canonicalType.instanceTypeOfMetatype.nominal,
         !nominal.isGenericAtAnyLevel,
-        !nominal.isResilient(in: mti.parentFunction) {
+        !nominal.isResilient(in: mti.parentFunction),
+        nominal.parentModule == context.currentModuleContext {
         return true
       }
       return false

test/SILOptimizer/static_init_metatypes.swift

@@ -16,38 +16,31 @@ public struct S: Hashable, Sendable, MyProtocol, MyProtocol2 {}
 extension Int: MyProtocol, MyProtocol2 {}
 
 public let metatype1 = Int.self
-// SIL:      sil_global [let] @$s4test9metatype1Simvp : $@thin Int.Type = {
-// SIL-NEXT:   %initval = metatype $@thin Int.Type
-// SIL-NEXT: }
+// SIL: sil_global [let] @$s4test9metatype1Simvp : $@thin Int.Type
+// SIL-EMPTY:
 public let metatype2 = S.self
 // SIL:      sil_global [let] @$s4test9metatype2AA1SVmvp : $@thin S.Type = {
 // SIL-NEXT:   %initval = metatype $@thin S.Type
 // SIL-NEXT: }
 public let metatype3: Any.Type = Int.self
-// SIL:      sil_global [let] @$s4test9metatype3ypXpvp : $@thick any Any.Type = {
-// SIL-NEXT:   %0 = metatype $@thick Int.Type                  // user: %1
-// SIL-NEXT:   %initval = init_existential_metatype %0, $@thick any Any.Type
-// SIL-NEXT: }
+// SIL: sil_global [let] @$s4test9metatype3ypXpvp : $@thick any Any.Type
+// SIL-EMPTY:
 public let metatype4: Any.Type = S.self
 // SIL:      sil_global [let] @$s4test9metatype4ypXpvp : $@thick any Any.Type = {
 // SIL-NEXT:   %0 = metatype $@thick S.Type                    // user: %1
 // SIL-NEXT:   %initval = init_existential_metatype %0, $@thick any Any.Type
 // SIL-NEXT: }
 public let metatype5: any MyProtocol.Type = Int.self
-// SIL:      sil_global [let] @$s4test9metatype5AA10MyProtocol_pXpvp : $@thick any MyProtocol.Type = {
-// SIL-NEXT:   %0 = metatype $@thick Int.Type                  // user: %1
-// SIL-NEXT:   %initval = init_existential_metatype %0, $@thick any MyProtocol.Type
-// SIL-NEXT: }
+// SIL: sil_global [let] @$s4test9metatype5AA10MyProtocol_pXpvp : $@thick any MyProtocol.Type
+// SIL-EMPTY:
 public let metatype6: any MyProtocol.Type = S.self
 // SIL:      sil_global [let] @$s4test9metatype6AA10MyProtocol_pXpvp : $@thick any MyProtocol.Type = {
 // SIL-NEXT:   %0 = metatype $@thick S.Type                    // user: %1
 // SIL-NEXT:   %initval = init_existential_metatype %0, $@thick any MyProtocol.Type
 // SIL-NEXT: }
 public let metatype7: any (MyProtocol & MyProtocol2).Type = Int.self
-// SIL:      sil_global [let] @$s4test9metatype7AA10MyProtocol_AA0C9Protocol2pXpvp : $@thick any (MyProtocol & MyProtocol2).Type = {
-// SIL-NEXT:   %0 = metatype $@thick Int.Type                  // user: %1
-// SIL-NEXT:   %initval = init_existential_metatype %0, $@thick any (MyProtocol & MyProtocol2).Type
-// SIL-NEXT: }
+// SIL: sil_global [let] @$s4test9metatype7AA10MyProtocol_AA0C9Protocol2pXpvp : $@thick any (MyProtocol & MyProtocol2).Type
+// SIL-EMPTY:
 public let metatype8: any (MyProtocol & MyProtocol2).Type = S.self
 // SIL:      sil_global [let] @$s4test9metatype8AA10MyProtocol_AA0C9Protocol2pXpvp : $@thick any (MyProtocol & MyProtocol2).Type = {
 // SIL-NEXT:   %0 = metatype $@thick S.Type                    // user: %1
@@ -100,9 +93,6 @@ public var metatype22: [Any.Type] = [S.self]
 @main
 struct Main { static func main() { } }
 
-// IR: @"$s4test9metatype3ypXpvp" = {{.*}}constant ptr @"$sSiN"
 // IR: @"$s4test9metatype4ypXpvp" = {{.*}}constant ptr getelementptr inbounds{{.*}} ({{.*}}, ptr @"$s4test1SVMf", {{.*}})
-// IR: @"$s4test9metatype5AA10MyProtocol_pXpvp" = {{.*}}constant <{ ptr, ptr }> <{ ptr @"$sSiN", ptr @"$sSi4test10MyProtocolAAWP" }>
 // IR: @"$s4test9metatype6AA10MyProtocol_pXpvp" = {{.*}}constant <{ ptr, ptr }> <{ ptr getelementptr inbounds{{.*}} ({{.*}}, ptr @"$s4test1SVMf", {{.*}}), ptr @"$s4test1SVAA10MyProtocolAAWP" }>
-// IR: @"$s4test9metatype7AA10MyProtocol_AA0C9Protocol2pXpvp" = {{.*}}constant <{ ptr, ptr, ptr }> <{ ptr @"$sSiN", ptr @"$sSi4test10MyProtocolAAWP", ptr @"$sSi4test11MyProtocol2AAWP" }>
 // IR: @"$s4test9metatype8AA10MyProtocol_AA0C9Protocol2pXpvp" = {{.*}}constant <{ ptr, ptr, ptr }> <{ ptr getelementptr inbounds{{.*}} ({{.*}}, ptr @"$s4test1SVMf", {{.*}}), ptr @"$s4test1SVAA10MyProtocolAAWP", ptr @"$s4test1SVAA11MyProtocol2AAWP" }>

test/SILOptimizer/static_init_metatypes2.swift

@@ -0,0 +1,25 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -parse-as-library -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -O
+// RUN: %target-swift-frontend -parse-as-library -I %t %t/Main.swift -O -emit-sil | %FileCheck %s --check-prefix SIL
+// RUN: %target-swift-frontend -parse-as-library -I %t %t/Main.swift -O -emit-ir | %FileCheck %s --check-prefix IR
+
+// BEGIN MyModule.swift
+
+public class MyClass {}
+
+// BEGIN Main.swift
+
+import MyModule
+
+public let classMetatype = MyClass.self
+public let classMetatypeArray = [classMetatype]
+
+// SIL: sil_global [let] @$s4Main13classMetatype8MyModule0D5ClassCmvp : $@thick MyClass.Type
+// SIL-EMPTY:
+// SIL: sil_global [let] @$s4Main18classMetatypeArraySay8MyModule0E5ClassCmGvp : $Array<MyClass.Type>
+// SIL-EMPTY:
+
+// IR: @"$s4Main13classMetatype8MyModule0D5ClassCmvp" = global ptr null
+// IR: @"$s4Main18classMetatypeArraySay8MyModule0E5ClassCmGvp" = global %TSa zeroinitializer