Kapt+JVM_IR: do not require KtFile for each generated class

In particular, JVM IR doesn't provide KtFile for a multifile facade in
JvmDeclarationOrigin (JVM backend provides KtFile of a random multifile
part). This led to multifile classes being completely ignored in the
JVM_IR version of kapt. Now they are generated correctly and the changed
test passes, but there's a _ir.txt expectation file because the order of
'foo' and 'bar' is different (which is not a problem).

plugins/kapt3/kapt3-compiler/src/org/jetbrains/kotlin/kapt3/stubs/ClassFileToSourceStubConverter.kt

@@ -52,6 +52,7 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.ArrayFqNames
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DelegatingBindingTrace
+import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.calls.model.DefaultValueArgument
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedValueArgument
 import org.jetbrains.kotlin.resolve.calls.util.getResolvedCall
@@ -64,9 +65,9 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassOrAny
 import org.jetbrains.kotlin.resolve.descriptorUtil.isCompanionObject
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOrigin
 import org.jetbrains.kotlin.resolve.source.getPsi
+import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.error.ErrorTypeKind
 import org.jetbrains.kotlin.types.error.ErrorUtils
-import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.isError
 import org.jetbrains.kotlin.types.typeUtil.isEnum
 import org.jetbrains.org.objectweb.asm.Opcodes
@@ -206,7 +207,6 @@ class ClassFileToSourceStubConverter(val kaptContext: KaptContextForStubGenerati
 
     private fun convertTopLevelClass(clazz: ClassNode): KaptStub? {
         val origin = kaptContext.origins[clazz] ?: return null
-        val ktFile = origin.element?.containingFile as? KtFile ?: return null
         val descriptor = origin.descriptor ?: return null
 
         // Nested classes will be processed during the outer classes conversion
@@ -214,14 +214,17 @@ class ClassFileToSourceStubConverter(val kaptContext: KaptContextForStubGenerati
 
         val lineMappings = KaptLineMappingCollector(kaptContext)
 
-        val packageName = ktFile.packageFqName.asString()
+        val packageName = DescriptorUtils.getParentOfType(descriptor, PackageFragmentDescriptor::class.java, false)?.fqName?.asString()
+            ?: return null
+
         val packageClause = if (packageName.isEmpty()) null else treeMaker.FqName(packageName)
 
         val classDeclaration = convertClass(clazz, lineMappings, packageName, true) ?: return null
 
         classDeclaration.mods.annotations = classDeclaration.mods.annotations
 
-        val imports = if (correctErrorTypes) convertImports(ktFile, classDeclaration) else JavacList.nil()
+        val ktFile = origin.element?.containingFile as? KtFile
+        val imports = if (ktFile != null && correctErrorTypes) convertImports(ktFile, classDeclaration) else JavacList.nil()
 
         val classes = JavacList.of<JCTree>(classDeclaration)
 

plugins/kapt3/kapt3-compiler/testData/converter/multifileClass.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 // WITH_STDLIB
 
 // FILE: a.kt

plugins/kapt3/kapt3-compiler/testData/converter/multifileClass_ir.txt

@@ -0,0 +1,30 @@
+package test;
+
+@kotlin.Metadata()
+public final class M1 {
+
+    public M1() {
+        super();
+    }
+
+    public static final void bar() {
+    }
+
+    public static final void foo() {
+    }
+}
+
+////////////////////
+
+package test;
+
+@kotlin.Metadata()
+public final class M2 {
+
+    public M2() {
+        super();
+    }
+
+    public static final void baz() {
+    }
+}