[IR] Add a method to get ModuleDescriptor from IrPackageFragment

Ideally, instead of this method, there should be a link
to IrModuleFragment. Unfortunately, it would require to big refactoring,
as some of IrPackageFragment implementations doesn't have any
IrModuleFragment inside, and are not located inside any
IrModuleFragment.

So for now, we just implement and use everywhere a single way of
getting the module descriptor, which respects a IrModuleFragment
link if it exists, and fallbacks to descriptor-based method
if it doesn't.

^KT-62623

compiler/ir/ir.tree/gen/org/jetbrains/kotlin/ir/declarations/IrPackageFragment.kt

@@ -8,6 +8,7 @@
 
 package org.jetbrains.kotlin.ir.declarations
 
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.ir.IrElementBase
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
@@ -25,6 +26,15 @@ abstract class IrPackageFragment : IrElementBase(), IrDeclarationContainer, IrSy
     @ObsoleteDescriptorBasedAPI
     abstract val packageFragmentDescriptor: PackageFragmentDescriptor
 
+    /**
+     * This should be a link to [IrModuleFragment] instead. 
+     *    
+     * Unfortunately, some package fragments (e.g. some synthetic ones and
+     * [IrExternalPackageFragment])
+     * are not located in any IR module, but still have a module descriptor. 
+     */
+    abstract val moduleDescriptor: ModuleDescriptor
+
     abstract var packageFqName: FqName
 
     @Deprecated(

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrExternalPackageFragmentImpl.kt

@@ -47,6 +47,10 @@ class IrExternalPackageFragmentImpl(
     override val packageFragmentDescriptor: PackageFragmentDescriptor
         get() = symbol.descriptor
 
+    @OptIn(ObsoleteDescriptorBasedAPI::class)
+    override val moduleDescriptor: ModuleDescriptor
+        get() = packageFragmentDescriptor.containingDeclaration
+
     override val declarations: MutableList<IrDeclaration> = ArrayList()
 
     @OptIn(ObsoleteDescriptorBasedAPI::class)

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFileImpl.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.ir.declarations.impl
 
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.ir.IrFileEntry
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
@@ -69,6 +70,15 @@ class IrFileImpl(
     override val packageFragmentDescriptor: PackageFragmentDescriptor
         get() = symbol.descriptor
 
+    @OptIn(ObsoleteDescriptorBasedAPI::class)
+    override val moduleDescriptor: ModuleDescriptor
+        get() {
+            return if (this::module.isInitialized)
+                module.descriptor
+            else
+                packageFragmentDescriptor.containingDeclaration
+        }
+
     override val declarations: MutableList<IrDeclaration> = ArrayList()
 
     override var annotations: List<IrConstructorCall> = emptyList()

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/overrides/FakeOverrideBuilderStrategy.kt

@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.ir.overrides
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
-import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
@@ -94,14 +93,13 @@ abstract class FakeOverrideBuilderStrategy(
     protected abstract fun linkPropertyFakeOverride(property: IrPropertyWithLateBinding, manglerCompatibleMode: Boolean)
 }
 
-@OptIn(ObsoleteDescriptorBasedAPI::class) // Because of the LazyIR, have to use descriptors here.
 private fun IrOverridableMember.isPrivateToThisModule(
     thisClass: IrClass, memberClass: IrClass, friendModules: Map<String, Collection<String>>,
 ): Boolean {
     if (visibility != DescriptorVisibilities.INTERNAL) return false
 
-    val thisModule = thisClass.getPackageFragment().packageFragmentDescriptor.containingDeclaration
-    val memberModule = memberClass.getPackageFragment().packageFragmentDescriptor.containingDeclaration
+    val thisModule = thisClass.getPackageFragment().moduleDescriptor
+    val memberModule = memberClass.getPackageFragment().moduleDescriptor
 
     return thisModule != memberModule && !isInFriendModules(thisModule, memberModule, friendModules)
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/impl/IrErrorClassImpl.kt

@@ -5,10 +5,7 @@
 
 package org.jetbrains.kotlin.ir.types.impl
 
-import org.jetbrains.kotlin.descriptors.ClassKind
-import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
-import org.jetbrains.kotlin.descriptors.Modality
-import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.IrFileEntry
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
@@ -50,6 +47,8 @@ object IrErrorClassImpl : IrClassImpl(
             @ObsoleteDescriptorBasedAPI
             override val packageFragmentDescriptor: PackageFragmentDescriptor
                 get() = TODO("Not yet implemented")
+            override val moduleDescriptor: ModuleDescriptor
+                get() = TODO("Not yet implemented")
             override var packageFqName: FqName
                 get() = FqName.ROOT
                 set(_) = TODO("Not yet implemented")

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/dumpKotlinLike.kt

@@ -263,7 +263,7 @@ private class KotlinLikeDumper(val p: Printer, val options: KotlinLikeDumpOption
         if (options.printFileName) p.println("// FILE: ${declaration.name}")
         if (options.printFilePath) p.println("// path: ${declaration.path}")
         declaration.printlnAnnotations("file")
-        val packageFqName = declaration.packageFragmentDescriptor.fqName
+        val packageFqName = declaration.packageFqName
         if (!packageFqName.isRoot) {
             p.println("package ${packageFqName.asString()}")
         }

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/IrTree.kt

@@ -618,6 +618,14 @@ object IrTree : AbstractTreeBuilder() {
 
         +symbol(packageFragmentSymbolType)
         +field("packageFragmentDescriptor", type(Packages.descriptors, "PackageFragmentDescriptor"), mutable = false)
+        +field("moduleDescriptor", type(Packages.descriptors, "ModuleDescriptor"), mutable = false) {
+            kdoc = """
+            This should be a link to [IrModuleFragment] instead. 
+               
+            Unfortunately, some package fragments (e.g. some synthetic ones and [IrExternalPackageFragment])
+            are not located in any IR module, but still have a module descriptor. 
+            """.trimIndent()
+        }
         +field("packageFqName", type<FqName>())
         +field("fqName", type<FqName>()) {
             baseGetter = code("packageFqName")

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/KotlinIrLinker.kt

@@ -181,14 +181,14 @@ abstract class KotlinIrLinker(
     override fun tryReferencingSimpleFunctionByLocalSignature(parent: IrDeclaration, idSignature: IdSignature): IrSimpleFunctionSymbol? {
         if (idSignature.isPubliclyVisible) return null
         val file = getFileOf(parent)
-        val moduleDescriptor = file.packageFragmentDescriptor.containingDeclaration
+        val moduleDescriptor = file.moduleDescriptor
         return resolveModuleDeserializer(moduleDescriptor, null).referenceSimpleFunctionByLocalSignature(file, idSignature)
     }
 
     override fun tryReferencingPropertyByLocalSignature(parent: IrDeclaration, idSignature: IdSignature): IrPropertySymbol? {
         if (idSignature.isPubliclyVisible) return null
         val file = getFileOf(parent)
-        val moduleDescriptor = file.packageFragmentDescriptor.containingDeclaration
+        val moduleDescriptor = file.moduleDescriptor
         return resolveModuleDeserializer(moduleDescriptor, null).referencePropertyByLocalSignature(file, idSignature)
     }