Fir2Ir: deserialize bodies of inline functions

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrComponents.kt

@@ -41,4 +41,6 @@ interface Fir2IrComponents {
     val callGenerator: CallAndReferenceGenerator
     val fakeOverrideGenerator: FakeOverrideGenerator
     val delegatedMemberGenerator: DelegatedMemberGenerator
+
+    val extensions: Fir2IrExtensions
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrComponentsStorage.kt

@@ -23,7 +23,8 @@ class Fir2IrComponentsStorage(
     override val scopeSession: ScopeSession,
     override val symbolTable: SymbolTable,
     override val irFactory: IrFactory,
-    override val signatureComposer: FirBasedSignatureComposer
+    override val signatureComposer: FirBasedSignatureComposer,
+    override val extensions: Fir2IrExtensions,
 ) : Fir2IrComponents {
 
     override lateinit var converter: Fir2IrConverter

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

@@ -430,7 +430,7 @@ class Fir2IrConverter(
             val moduleDescriptor = FirModuleDescriptor(session)
             val symbolTable = SymbolTable(signaturer, irFactory)
             val signatureComposer = FirBasedSignatureComposer(mangler)
-            val components = Fir2IrComponentsStorage(session, scopeSession, symbolTable, irFactory, signatureComposer)
+            val components = Fir2IrComponentsStorage(session, scopeSession, symbolTable, irFactory, signatureComposer, fir2IrExtensions)
             val converter = Fir2IrConverter(moduleDescriptor, components)
 
             components.converter = converter

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

@@ -57,13 +57,20 @@ class FirIrProvider(val fir2IrComponents: Fir2IrComponents) : IrProvider {
                 firClass = firClass.declarations.singleOrNull { (it as? FirRegularClass)?.name?.asString() == midName } as? FirRegularClass
                     ?: return null
             }
-            if (symbol is IrClassSymbol) {
-                firCandidates = listOf(firClass)
-                parent = classifierStorage.getIrClassSymbol(firParentClass!!.symbol).owner
-            } else {
-                val lastName = nameSegments.last()
-                firCandidates = firClass.declarations.filter { it is FirCallableDeclaration && it.symbol.name.asString() == lastName }
-                parent = firParentClass?.let { classifierStorage.getIrClassSymbol(it.symbol).owner } ?: packageFragment
+            when (symbol) {
+                is IrClassSymbol -> {
+                    firCandidates = listOf(firClass)
+                    parent = classifierStorage.getIrClassSymbol(firParentClass!!.symbol).owner
+                }
+                is IrConstructorSymbol -> {
+                    firCandidates = firClass.declarations.filter { it is FirConstructor }
+                    parent = classifierStorage.getIrClassSymbol(firClass.symbol).owner
+                }
+                else -> {
+                    val lastName = nameSegments.last()
+                    firCandidates = firClass.declarations.filter { it is FirCallableDeclaration && it.symbol.name.asString() == lastName }
+                    parent = classifierStorage.getIrClassSymbol(firClass.symbol).owner
+                }
             }
         }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/AbstractFir2IrLazyDeclaration.kt

@@ -15,12 +15,15 @@ import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationParent
 import org.jetbrains.kotlin.ir.declarations.IrFactory
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
+import org.jetbrains.kotlin.ir.declarations.lazy.IrLazyDeclarationBase
 import org.jetbrains.kotlin.ir.declarations.lazy.lazyVar
 import org.jetbrains.kotlin.ir.expressions.IrConstructorCall
+import org.jetbrains.kotlin.ir.util.DeclarationStubGenerator
+import org.jetbrains.kotlin.ir.util.TypeTranslator
 import kotlin.properties.ReadWriteProperty
 
 interface AbstractFir2IrLazyDeclaration<F, D : IrDeclaration> :
-    IrDeclaration, IrDeclarationParent, Fir2IrComponents where F : FirMemberDeclaration, F : FirAnnotationContainer {
+    IrDeclaration, IrDeclarationParent, IrLazyDeclarationBase, Fir2IrComponents where F : FirMemberDeclaration, F : FirAnnotationContainer {
 
     val fir: F
     override val symbol: Fir2IrBindableSymbol<*, D>
@@ -42,9 +45,18 @@ interface AbstractFir2IrLazyDeclaration<F, D : IrDeclaration> :
         }
     }
 
-    fun createLazyAnnotations(): ReadWriteProperty<Any?, List<IrConstructorCall>> = lazyVar(lock) {
+    override fun createLazyAnnotations(): ReadWriteProperty<Any?, List<IrConstructorCall>> = lazyVar(lock) {
         fir.annotations.mapNotNull {
             callGenerator.convertToIrConstructorCall(it) as? IrConstructorCall
         }
     }
+
+    override fun lazyParent(): IrDeclarationParent {
+        return parent
+    }
+
+    override val stubGenerator: DeclarationStubGenerator
+        get() = error("Should not be called")
+    override val typeTranslator: TypeTranslator
+        get() = error("Should not be called")
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/AbstractFir2IrLazyFunction.kt

@@ -101,11 +101,6 @@ abstract class AbstractFir2IrLazyFunction<F : FirCallableDeclaration>(
         }
     }
 
-    override val stubGenerator: DeclarationStubGenerator
-        get() = error("Should not be called")
-    override val typeTranslator: TypeTranslator
-        get() = error("Should not be called")
-
     override val factory: IrFactory
         get() = super<AbstractFir2IrLazyDeclaration>.factory
 

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

@@ -14,14 +14,13 @@ import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
 import org.jetbrains.kotlin.fir.initialSignatureAttr
 import org.jetbrains.kotlin.fir.symbols.Fir2IrSimpleFunctionSymbol
-import org.jetbrains.kotlin.ir.declarations.IrClass
-import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
-import org.jetbrains.kotlin.ir.declarations.IrFunction
-import org.jetbrains.kotlin.ir.declarations.IrValueParameter
+import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.lazy.lazyVar
+import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.expressions.IrConstructorCall
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.util.DeserializableClass
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedContainerSource
 
@@ -52,6 +51,10 @@ class Fir2IrLazySimpleFunction(
         fir.returnTypeRef.toIrType(typeConverter)
     }
 
+    override var body: IrBody? by lazyVar(lock) {
+        if (tryLoadIr()) body else null
+    }
+
     override var dispatchReceiverParameter: IrValueParameter? by lazyVar(lock) {
         val containingClass = parent as? IrClass
         if (containingClass != null && shouldHaveDispatchReceiver(containingClass, fir)) {
@@ -107,4 +110,19 @@ class Fir2IrLazySimpleFunction(
 
     override val containerSource: DeserializedContainerSource?
         get() = fir.containerSource
+
+    private fun tryLoadIr(): Boolean {
+        if (!isInline || isFakeOverride) return false
+        if (!extensions.irNeedsDeserialization) return false
+        val toplevel = getToplevel()
+        return (toplevel as? DeserializableClass)?.loadIr() ?: false
+    }
+
+    private fun getToplevel(): IrDeclaration {
+        var current: IrDeclaration = this
+        while (current.parent !is IrPackageFragment) {
+            current = current.parent as IrDeclaration
+        }
+        return current
+    }
 }