Refactor ApiVersion.KOTLIN_1_4 usages in relation to unified null checks

compiler/backend/src/org/jetbrains/kotlin/codegen/AsmUtil.java

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.codegen.intrinsics.HashCode;
 import org.jetbrains.kotlin.codegen.intrinsics.IntrinsicMethods;
 import org.jetbrains.kotlin.codegen.state.GenerationState;
 import org.jetbrains.kotlin.codegen.state.KotlinTypeMapper;
-import org.jetbrains.kotlin.config.ApiVersion;
 import org.jetbrains.kotlin.config.JvmTarget;
 import org.jetbrains.kotlin.config.LanguageFeature;
 import org.jetbrains.kotlin.config.LanguageVersionSettings;
@@ -1023,9 +1022,7 @@ public class AsmUtil {
             }
             value.put(asmType, v);
             v.visitLdcInsn(name);
-            String methodName = state.getLanguageVersionSettings().getApiVersion().compareTo(ApiVersion.KOTLIN_1_4) >= 0
-                                ? "checkNotNullParameter"
-                                : "checkParameterIsNotNull";
+            String methodName = state.getUnifiedNullChecks() ? "checkNotNullParameter" : "checkParameterIsNotNull";
             v.invokestatic(IntrinsicMethods.INTRINSICS_CLASS_NAME, methodName, "(Ljava/lang/Object;Ljava/lang/String;)V", false);
         }
     }
@@ -1048,9 +1045,7 @@ public class AsmUtil {
                 if (innerType.getSort() == Type.OBJECT || innerType.getSort() == Type.ARRAY) {
                     v.dup();
                     v.visitLdcInsn(runtimeAssertionInfo.getMessage());
-                    String methodName = state.getLanguageVersionSettings().getApiVersion().compareTo(ApiVersion.KOTLIN_1_4) >= 0
-                                        ? "checkNotNullExpressionValue"
-                                        : "checkExpressionValueIsNotNull";
+                    String methodName = state.getUnifiedNullChecks() ? "checkNotNullExpressionValue" : "checkExpressionValueIsNotNull";
                     v.invokestatic(IntrinsicMethods.INTRINSICS_CLASS_NAME, methodName, "(Ljava/lang/Object;Ljava/lang/String;)V", false);
                 }
                 StackValue.coerce(innerType, innerKotlinType, type, kotlinType, v);

compiler/backend/src/org/jetbrains/kotlin/codegen/ExpressionCodegen.java

@@ -4250,7 +4250,7 @@ public class ExpressionCodegen extends KtVisitor<StackValue, StackValue> impleme
             return StackValue.operation(base.type, base.kotlinType, v -> {
                 base.put(base.type, base.kotlinType, v);
                 v.dup();
-                if (state.getLanguageVersionSettings().getApiVersion().compareTo(ApiVersion.KOTLIN_1_4) >= 0) {
+                if (state.getUnifiedNullChecks()) {
                     v.invokestatic(IntrinsicMethods.INTRINSICS_CLASS_NAME, "checkNotNull", "(Ljava/lang/Object;)V", false);
                 } else {
                     Label ok = new Label();

compiler/backend/src/org/jetbrains/kotlin/codegen/serialization/JvmSerializerExtension.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.codegen.createFreeFakeLocalPropertyDescriptor
 import org.jetbrains.kotlin.codegen.serialization.JvmSerializationBindings.*
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.codegen.state.KotlinTypeMapperBase
-import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.load.java.JvmAbi
@@ -53,6 +52,7 @@ class JvmSerializerExtension @JvmOverloads constructor(
     private val classBuilderMode = state.classBuilderMode
     private val languageVersionSettings = state.languageVersionSettings
     private val isParamAssertionsDisabled = state.isParamAssertionsDisabled
+    private val unifiedNullChecks = state.unifiedNullChecks
     override val metadataVersion = state.metadataVersion
 
     override fun shouldUseTypeTable(): Boolean = useTypeTable
@@ -191,7 +191,7 @@ class JvmSerializerExtension @JvmOverloads constructor(
     }
 
     private fun MutableVersionRequirementTable.writeInlineParameterNullCheckRequirement(add: (Int) -> Unit) {
-        if (languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4) {
+        if (unifiedNullChecks) {
             // Since Kotlin 1.4, we generate a call to Intrinsics.checkNotNullParameter in inline functions which causes older compilers
             // (earlier than 1.3.50) to crash because a functional parameter in this position can't be inlined
             add(writeVersionRequirement(1, 3, 50, ProtoBuf.VersionRequirement.VersionKind.COMPILER_VERSION, this))

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -242,6 +242,7 @@ class GenerationState private constructor(
     val assertionsMode: JVMAssertionsMode = configuration.get(JVMConfigurationKeys.ASSERTIONS_MODE, JVMAssertionsMode.DEFAULT)
     val isInlineDisabled: Boolean = configuration.getBoolean(CommonConfigurationKeys.DISABLE_INLINE)
     val useTypeTableInSerializer: Boolean = configuration.getBoolean(JVMConfigurationKeys.USE_TYPE_TABLE)
+    val unifiedNullChecks: Boolean = languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4
 
     val rootContext: CodegenContext<*> = RootContext(this)
 

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt

@@ -28,7 +28,6 @@ import org.jetbrains.kotlin.codegen.intrinsics.TypeIntrinsics
 import org.jetbrains.kotlin.codegen.pseudoInsns.fakeAlwaysFalseIfeq
 import org.jetbrains.kotlin.codegen.pseudoInsns.fixStackAndJump
 import org.jetbrains.kotlin.codegen.signature.BothSignatureWriter
-import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.isReleaseCoroutines
 import org.jetbrains.kotlin.config.languageVersionSettings
@@ -283,9 +282,7 @@ class ExpressionCodegen(
         if (!param.type.unboxInlineClass().isNullable() && !isPrimitive(asmType)) {
             mv.load(findLocalIndex(param.symbol), asmType)
             mv.aconst(param.name.asString())
-            val methodName =
-                if (state.languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4) "checkNotNullParameter"
-                else "checkParameterIsNotNull"
+            val methodName = if (state.unifiedNullChecks) "checkNotNullParameter" else "checkParameterIsNotNull"
             mv.invokestatic(IrIntrinsicMethods.INTRINSICS_CLASS_NAME, methodName, "(Ljava/lang/Object;Ljava/lang/String;)V", false)
         }
     }

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

@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.common.lower.irIfThen
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
-import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.expressions.IrCall
@@ -43,7 +42,7 @@ private class CheckNotNullLowering(private val backendContext: JvmBackendContext
             // Starting with Kotlin 1.4 null-checks are lowered to calls to the "checkNotNull" intrinsic, which
             // throws a NullPointerException on failure. Prior to Kotlin 1.4 we instead inline the null-check and
             // call the "throwNpe" intrinsic on failure which throws a KotlinNullPointerException.
-            if (backendContext.state.languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4) {
+            if (backendContext.state.unifiedNullChecks) {
                 +irCall(backendContext.ir.symbols.checkNotNull).apply {
                     putValueArgument(0, irGet(argument))
                 }

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

@@ -7,11 +7,8 @@ package org.jetbrains.kotlin.backend.jvm.lower
 
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.lower.SpecialBridgeMethods
-import org.jetbrains.kotlin.backend.common.lower.flattenStringConcatenationPhase
-import org.jetbrains.kotlin.backend.common.lower.loops.forLoopsPhase
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
-import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -35,7 +32,7 @@ private enum class AssertionScope {
 
 private class JvmArgumentNullabilityAssertionsLowering(context: JvmBackendContext) : FileLoweringPass, IrElementTransformer<AssertionScope> {
 
-    private val isWithUnifiedNullChecks = context.state.languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4
+    private val isWithUnifiedNullChecks = context.state.unifiedNullChecks
     private val isCallAssertionsDisabled = context.state.isCallAssertionsDisabled
     private val isReceiverAssertionsDisabled = context.state.isReceiverAssertionsDisabled
 

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

@@ -14,7 +14,6 @@ import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.codegen.fileParent
 import org.jetbrains.kotlin.backend.jvm.ir.erasedUpperBound
-import org.jetbrains.kotlin.config.ApiVersion
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
@@ -184,18 +183,14 @@ private class TypeOperatorLowering(private val context: JvmBackendContext) : Fil
     private fun sourceViewFor(declaration: IrDeclaration) =
         context.psiSourceManager.getKtFile(declaration.fileParent)!!.viewProvider.contents
 
-    // Since Kotlin 1.4 we throw NullPointerExceptions instead of more specialized exception classes.
-    private val useNullPointerExceptions: Boolean
-        get() = context.state.languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4
-
     private val typeCastException: IrFunctionSymbol =
-        if (useNullPointerExceptions)
+        if (context.state.unifiedNullChecks)
             context.ir.symbols.ThrowNullPointerException
         else
             context.ir.symbols.ThrowTypeCastException
 
     private val checkExpressionValueIsNotNull: IrFunctionSymbol =
-        if (useNullPointerExceptions)
+        if (context.state.unifiedNullChecks)
             context.ir.symbols.checkNotNullExpressionValue
         else
             context.ir.symbols.checkExpressionValueIsNotNull