Fir2Ir: enable IR-based fake override builder

Invert the logic of IR/FIR2IR-based generators: change the CLI argument
to -Xuse-fir-fake-override-builder, test directive to
USE_FIR_BASED_FAKE_OVERRIDE_GENERATOR, etc.

The changes in test data caused by using IR fake override builder by
default are in the subsequent commit.

 #KT-61514

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/pipeline/convertToIr.kt

@@ -107,12 +107,12 @@ fun FirResult.convertToIrAndActualize(
         ),
         actualizerTypeContextProvider(irModuleFragment.irBuiltins),
         fir2IrConfiguration.expectActualTracker,
-        fir2IrConfiguration.useIrFakeOverrideBuilder,
+        fir2IrConfiguration.useFirBasedFakeOverrideGenerator,
         irModuleFragment,
         allIrModules.dropLast(1),
     )
 
-    if (fir2IrConfiguration.useIrFakeOverrideBuilder) {
+    if (!fir2IrConfiguration.useFirBasedFakeOverrideGenerator) {
         // actualizeCallablesAndMergeModules call below in fact can also actualize classifiers.
         // So to avoid even more changes, when this mode is disabled, we don't run classifiers
         // actualization separately. This should go away, after useIrFakeOverrideBuilder becomes
@@ -122,7 +122,7 @@ fun FirResult.convertToIrAndActualize(
         components.fakeOverrideBuilder.buildForAll(allIrModules, temporaryResolver)
     }
     val expectActualMap = irActualizer?.actualizeCallablesAndMergeModules() ?: emptyMap()
-    if (components.configuration.useIrFakeOverrideBuilder) {
+    if (!components.configuration.useFirBasedFakeOverrideGenerator) {
         val fakeOverrideResolver = SpecialFakeOverrideSymbolsResolver(expectActualMap)
         irModuleFragment.acceptVoid(SpecialFakeOverrideSymbolsResolverVisitor(fakeOverrideResolver))
         @OptIn(Fir2IrSymbolsMappingForLazyClasses.SymbolRemapperInternals::class)

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConfiguration.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.constant.EvaluatedConstTracker
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.incremental.components.ExpectActualTracker
 import org.jetbrains.kotlin.incremental.components.InlineConstTracker
-import org.jetbrains.kotlin.ir.util.SymbolTable
 
 /**
  * @param allowNonCachedDeclarations
@@ -30,8 +29,9 @@ import org.jetbrains.kotlin.ir.util.SymbolTable
  *  Code generation in the IDE is trickier, though, as declarations from any module can be potentially referenced.
  *  For such a scenario, there is a flag that relaxes consistency checks.
  *
- * @param useIrFakeOverrideBuilder Enables creation of fake-overrides using the IR f/o generator instead of the FIR2IR one.
- *  See [KT-61514](https://youtrack.jetbrains.com/issue/KT-61514).
+ * @param useFirBasedFakeOverrideGenerator
+ *  Generate all fake overrides via FIR2IR instead of IR, i.e. revert to behavior before
+ *  [KT-61514](https://youtrack.jetbrains.com/issue/KT-61514) was resolved.
  */
 class Fir2IrConfiguration private constructor(
     val languageVersionSettings: LanguageVersionSettings,
@@ -40,9 +40,8 @@ class Fir2IrConfiguration private constructor(
     val inlineConstTracker: InlineConstTracker?,
     val expectActualTracker: ExpectActualTracker?,
     val allowNonCachedDeclarations: Boolean,
-    val useIrFakeOverrideBuilder: Boolean,
+    val useFirBasedFakeOverrideGenerator: Boolean,
 ) {
-
     companion object {
         fun forJvmCompilation(
             compilerConfiguration: CompilerConfiguration,
@@ -58,7 +57,7 @@ class Fir2IrConfiguration private constructor(
                 inlineConstTracker = compilerConfiguration[CommonConfigurationKeys.INLINE_CONST_TRACKER],
                 expectActualTracker = compilerConfiguration[CommonConfigurationKeys.EXPECT_ACTUAL_TRACKER],
                 allowNonCachedDeclarations = false,
-                useIrFakeOverrideBuilder = compilerConfiguration.getBoolean(CommonConfigurationKeys.USE_IR_FAKE_OVERRIDE_BUILDER),
+                useFirBasedFakeOverrideGenerator = compilerConfiguration.getBoolean(CommonConfigurationKeys.USE_FIR_BASED_FAKE_OVERRIDE_GENERATOR),
             )
 
         fun forKlibCompilation(
@@ -75,7 +74,7 @@ class Fir2IrConfiguration private constructor(
                 inlineConstTracker = null,
                 expectActualTracker = compilerConfiguration[CommonConfigurationKeys.EXPECT_ACTUAL_TRACKER],
                 allowNonCachedDeclarations = false,
-                useIrFakeOverrideBuilder = true,
+                useFirBasedFakeOverrideGenerator = false,
             )
 
         fun forAnalysisApi(
@@ -93,7 +92,7 @@ class Fir2IrConfiguration private constructor(
                 inlineConstTracker = compilerConfiguration[CommonConfigurationKeys.INLINE_CONST_TRACKER],
                 expectActualTracker = compilerConfiguration[CommonConfigurationKeys.EXPECT_ACTUAL_TRACKER],
                 allowNonCachedDeclarations = true,
-                useIrFakeOverrideBuilder = compilerConfiguration.getBoolean(CommonConfigurationKeys.USE_IR_FAKE_OVERRIDE_BUILDER),
+                useFirBasedFakeOverrideGenerator = compilerConfiguration.getBoolean(CommonConfigurationKeys.USE_FIR_BASED_FAKE_OVERRIDE_GENERATOR),
             )
     }
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -93,8 +93,8 @@ class Fir2IrConverter(
             processFileAndClassMembers(firFile)
         }
         //   4. Override processing which sets overridden symbols for everything inside non-local regular classes
-        @OptIn(FirBasedFakeOverrideGenerator::class) // checked for useIrFakeOverrideBuilder
-        if (!configuration.useIrFakeOverrideBuilder) {
+        @OptIn(FirBasedFakeOverrideGenerator::class)
+        if (configuration.useFirBasedFakeOverrideGenerator) {
             for (firFile in allFirFiles) {
                 bindFakeOverridesInFile(firFile)
             }
@@ -119,7 +119,7 @@ class Fir2IrConverter(
         }
 
         if (
-            !configuration.useIrFakeOverrideBuilder &&
+            configuration.useFirBasedFakeOverrideGenerator &&
             components.session.languageVersionSettings.supportsFeature(LanguageFeature.MultiPlatformProjects)
         ) {
             // See the comment to generateUnboundFakeOverrides function itself
@@ -287,8 +287,8 @@ class Fir2IrConverter(
             declarationStorage.leaveScope(irConstructor.symbol)
         }
 
-        if (!configuration.useIrFakeOverrideBuilder) {
-            @OptIn(FirBasedFakeOverrideGenerator::class) // checked for useIrFakeOverrideBuilder
+        if (configuration.useFirBasedFakeOverrideGenerator) {
+            @OptIn(FirBasedFakeOverrideGenerator::class)
             fakeOverrideGenerator.computeFakeOverrides(klass, irClass, allDeclarations)
         }
 
@@ -392,10 +392,9 @@ class Fir2IrConverter(
     }
 
     // `irClass` is a source class and definitely is not a lazy class
-    // checked for useIrFakeOverrideBuilder
     @OptIn(UnsafeDuringIrConstructionAPI::class, FirBasedFakeOverrideGenerator::class)
     fun bindFakeOverridesInClass(klass: IrClass) {
-        if (configuration.useIrFakeOverrideBuilder) return
+        if (!configuration.useFirBasedFakeOverrideGenerator) return
         require(klass !is Fir2IrLazyClass)
         fakeOverrideGenerator.bindOverriddenSymbols(klass.declarations)
         delegatedMemberGenerator.bindDelegatedMembersOverriddenSymbols(klass)

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -395,7 +395,7 @@ class Fir2IrDeclarationStorage(
         parentIsExternal: Boolean
     ): IrSimpleFunctionSymbol {
         if (
-            !configuration.useIrFakeOverrideBuilder ||
+            configuration.useFirBasedFakeOverrideGenerator ||
             parentIsExternal ||
             function !is FirSimpleFunction ||
             !function.isFakeOverride(fakeOverrideOwnerLookupTag)
@@ -592,7 +592,7 @@ class Fir2IrDeclarationStorage(
         parentIsExternal: Boolean
     ): PropertySymbols {
         if (
-            configuration.useIrFakeOverrideBuilder &&
+            !configuration.useFirBasedFakeOverrideGenerator &&
             !parentIsExternal &&
             property.isFakeOverride(fakeOverrideOwnerLookupTag)
         ) {
@@ -1189,7 +1189,7 @@ class Fir2IrDeclarationStorage(
                     )
                     irForFirSessionDependantDeclarationMap[key] = cachedInSymbolTable
                 }
-                configuration.useIrFakeOverrideBuilder -> {
+                !configuration.useFirBasedFakeOverrideGenerator -> {
                     /*
                      * If IR fake override builder is used for building fake-overrides, they are generated bypassing Fir2IrDeclarationStorage,
                      *   and are written directly to SymbolTable. So in this case it is normal to save the result from symbol table into

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/ClassMemberGenerator.kt

@@ -215,7 +215,7 @@ internal class ClassMemberGenerator(
                  * In useIrFakeOverrideBuilder it would be dropped anyway, as [org.jetbrains.kotlin.ir.overrides.IrFakeOverrideBuilder.buildFakeOverridesForClass]
                  * recalculates this value from scratch. Also, it's quite meaningless in non-platform modules anyway.
                  */
-                if (!configuration.useIrFakeOverrideBuilder) {
+                if (configuration.useFirBasedFakeOverrideGenerator) {
                     @OptIn(FirBasedFakeOverrideGenerator::class)
                     irFunction.overriddenSymbols = firFunction.generateOverriddenFunctionSymbols(containingClass)
                 }
@@ -234,7 +234,7 @@ internal class ClassMemberGenerator(
              * In useIrFakeOverrideBuilder it would be dropped anyway, as [org.jetbrains.kotlin.ir.overrides.IrFakeOverrideBuilder.buildFakeOverridesForClass]
              * recalculates this value from scratch. Also, it's quite meaningless in non-platform modules anyway.
              */
-            if (!configuration.useIrFakeOverrideBuilder) {
+            if (configuration.useFirBasedFakeOverrideGenerator) {
                 @OptIn(FirBasedFakeOverrideGenerator::class) // checked for useIrFakeOverrideBuilder
                 irProperty.overriddenSymbols = property.generateOverriddenPropertySymbols(containingClass)
             }
@@ -349,8 +349,8 @@ internal class ClassMemberGenerator(
                     declarationStorage.leaveScope(this.symbol)
                 }
             }
-            if (containingClass != null && !components.configuration.useIrFakeOverrideBuilder) {
-                @OptIn(FirBasedFakeOverrideGenerator::class) // checked for useIrFakeOverrideBuilder
+            if (containingClass != null && components.configuration.useFirBasedFakeOverrideGenerator) {
+                @OptIn(FirBasedFakeOverrideGenerator::class)
                 this.overriddenSymbols = property.generateOverriddenAccessorSymbols(containingClass, isGetter)
             }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DelegatedMemberGenerator.kt

@@ -197,9 +197,9 @@ class DelegatedMemberGenerator(private val components: Fir2IrComponents) : Fir2I
         return result
     }
 
-    @OptIn(FirBasedFakeOverrideGenerator::class) // checked for useIrFakeOverrideBuilder
+    @OptIn(FirBasedFakeOverrideGenerator::class)
     fun bindDelegatedMembersOverriddenSymbols(irClass: IrClass) {
-        if (components.configuration.useIrFakeOverrideBuilder) return
+        if (!components.configuration.useFirBasedFakeOverrideGenerator) return
         val superClasses by lazy(LazyThreadSafetyMode.NONE) {
             irClass.superTypes.mapNotNullTo(mutableSetOf()) {
                 // All class symbols should be already bound at this moment

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyProperty.kt

@@ -233,9 +233,9 @@ class Fir2IrLazyProperty(
     }
 
     override var overriddenSymbols: List<IrPropertySymbol> by symbolsMappingForLazyClasses.lazyMappedPropertyListVar(lock) {
-        when (configuration.useIrFakeOverrideBuilder) {
-            true -> computeOverriddenSymbolsForIrFakeOverrideGenerator()
-            false -> computeOverriddenUsingFir2IrFakeOverrideGenerator()
+        when (configuration.useFirBasedFakeOverrideGenerator) {
+            true -> computeOverriddenUsingFir2IrFakeOverrideGenerator()
+            false -> computeOverriddenSymbolsForIrFakeOverrideGenerator()
         }
     }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt

@@ -96,13 +96,12 @@ class Fir2IrLazySimpleFunction(
     }
 
     override var overriddenSymbols: List<IrSimpleFunctionSymbol> by symbolsMappingForLazyClasses.lazyMappedFunctionListVar(lock) {
-        when (configuration.useIrFakeOverrideBuilder) {
-            true -> computeOverriddenSymbolsForIrFakeOverrideGenerator()
-            false -> computeOverriddenUsingFir2IrFakeOverrideGenerator()
+        when (configuration.useFirBasedFakeOverrideGenerator) {
+            true -> computeOverriddenUsingFir2IrFakeOverrideGenerator()
+            false -> computeOverriddenSymbolsForIrFakeOverrideGenerator()
         }
     }
 
-
     // TODO: drop this function after migration to IR f/o generator will be complete (KT-64202)
     private fun computeOverriddenUsingFir2IrFakeOverrideGenerator(): List<IrSimpleFunctionSymbol> {
         if (firParent == null) return emptyList()

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenWithFir2IrFakeOverrideGeneratorTestGenerated.java

@@ -20,7 +20,7 @@ import java.util.regex.Pattern;
 @SuppressWarnings("all")
 @TestMetadata("compiler/testData/codegen/box")
 @TestDataPath("$PROJECT_ROOT")
-public class FirLightTreeBlackBoxCodegenWithIrFakeOverrideGeneratorTestGenerated extends AbstractFirLightTreeBlackBoxCodegenWithIrFakeOverrideGeneratorTest {
+public class FirLightTreeBlackBoxCodegenWithFir2IrFakeOverrideGeneratorTestGenerated extends AbstractFirLightTreeBlackBoxCodegenWithFir2IrFakeOverrideGeneratorTest {
   @Test
   public void testAllFilesPresentInBox() {
     KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true, "script");