JVM IR: run FileClass & ExpectDeclarationsRemoving phases on whole module

Since we now generate file classes even for IR loaded from dependencies
(see 3a9b94235f) to simplify code in certain lowerings, it makes sense
to do that for all source files together before any meaningful
lowerings. The easiest way to do so is to make FileClassLowering a
module-wide phase.

ExpectDeclarationsRemoveLowering is now also a module-wide phase because
it needs to be run before FileClassLowering (to avoid producing empty
facades for files that only contain `expect` declarations)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendFacade.kt

@@ -73,18 +73,16 @@ object JvmBackendFacade {
             facadeClassGenerator = ::facadeClassGenerator
         ).generateUnboundSymbolsAsDependencies()
 
-        val lower = JvmLower(context)
-
         for (irFile in irModuleFragment.files) {
-            try {
             for (extension in IrGenerationExtension.getInstances(context.state.project)) {
                 extension.generate(irFile, context, context.state.bindingContext)
             }
-
-                lower.lower(irFile)
-            } catch (e: Throwable) {
-                errorHandler.reportException(e, null) // TODO ktFile.virtualFile.url
         }
+
+        try {
+            JvmLower(context).lower(irModuleFragment)
+        } catch (e: Throwable) {
+            errorHandler.reportException(e, null)
         }
 
         for (irFile in irModuleFragment.files) {
@@ -98,7 +96,7 @@ object JvmBackendFacade {
                 }
                 state.afterIndependentPart()
             } catch (e: Throwable) {
-                errorHandler.reportException(e, null)
+                errorHandler.reportException(e, null) // TODO ktFile.virtualFile.url
             }
         }
     }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.backend.jvm.lower.*
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithName
 import org.jetbrains.kotlin.ir.declarations.IrFile
+import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.util.PatchDeclarationParentsVisitor
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.load.java.JvmAbi
@@ -41,7 +42,7 @@ private val arrayConstructorPhase = makeIrFilePhase(
     description = "Transform `Array(size) { index -> value }` into a loop"
 )
 
-private val expectDeclarationsRemovingPhase = makeIrFilePhase(
+private val expectDeclarationsRemovingPhase = makeIrModulePhase(
     ::ExpectDeclarationsRemoveLowering,
     name = "ExpectDeclarationsRemoving",
     description = "Remove expect declaration from module fragment"
@@ -90,12 +91,8 @@ private val innerClassesPhase = makeIrFilePhase(
     prerequisite = setOf(localDeclarationsPhase)
 )
 
-val jvmPhases = namedIrFilePhase<JvmBackendContext>(
+private val jvmFilePhases = inventNamesForLocalClassesPhase then
-    name = "IrLowering",
+
-    description = "IR lowering",
-    lower = expectDeclarationsRemovingPhase then
-            fileClassPhase then
-            inventNamesForLocalClassesPhase then
         kCallableNamePropertyPhase then
         arrayConstructorPhase then
 
@@ -160,11 +157,18 @@ val jvmPhases = namedIrFilePhase<JvmBackendContext>(
         // should be last transformation
         removeDeclarationsThatWouldBeInlined then
         makePatchParentsPhase(3)
+
+val jvmPhases = namedIrModulePhase(
+    name = "IrLowering",
+    description = "IR lowering",
+    lower = expectDeclarationsRemovingPhase then
+            fileClassPhase then
+            performByIrFile(lower = jvmFilePhases)
 )
 
 class JvmLower(val context: JvmBackendContext) {
-    fun lower(irFile: IrFile) {
+    fun lower(irModuleFragment: IrModuleFragment) {
         // TODO run lowering passes as callbacks in bottom-up visitor
-        jvmPhases.invokeToplevel(context.phaseConfig, context, irFile)
+        jvmPhases.invokeToplevel(context.phaseConfig, context, irModuleFragment)
     }
 }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/FileClassLowering.kt

@@ -19,7 +19,7 @@ package org.jetbrains.kotlin.backend.jvm.lower
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.descriptors.WrappedClassDescriptor
 import org.jetbrains.kotlin.backend.common.ir.createImplicitParameterDeclarationWithWrappedDescriptor
-import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
+import org.jetbrains.kotlin.backend.common.phaser.makeIrModulePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.codegen.AsmUtil
 import org.jetbrains.kotlin.descriptors.ClassKind
@@ -33,15 +33,17 @@ import org.jetbrains.kotlin.psi2ir.PsiSourceManager
 import org.jetbrains.kotlin.resolve.source.KotlinSourceElement
 import java.util.*
 
-internal val fileClassPhase = makeIrFilePhase(
+internal val fileClassPhase = makeIrModulePhase(
     ::FileClassLowering,
     name = "FileClass",
     description = "Put file level function and property declaration into a class",
     stickyPostconditions = setOf(::checkAllFileLevelDeclarationsAreClasses)
 )
 
-private fun checkAllFileLevelDeclarationsAreClasses(irFile: IrFile) {
+private fun checkAllFileLevelDeclarationsAreClasses(irModuleFragment: IrModuleFragment) {
-    assert(irFile.declarations.all { it is IrClass })
+    assert(irModuleFragment.files.all { irFile ->
+        irFile.declarations.all { it is IrClass }
+    })
 }
 
 private class FileClassLowering(val context: JvmBackendContext) : FileLoweringPass {