[Plugin API] Add API to load top level declaration by its signature

- request from JP Compose, #KT-44100

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/extensions/IrPluginContext.kt

@@ -10,7 +10,9 @@ import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.builders.IrGeneratorContext
+import org.jetbrains.kotlin.ir.linkage.IrDeserializer
 import org.jetbrains.kotlin.ir.symbols.*
+import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.ir.util.IrMessageLogger
 import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
 import org.jetbrains.kotlin.ir.util.TypeTranslator
@@ -51,4 +53,7 @@ interface IrPluginContext : IrGeneratorContext {
     fun referenceConstructors(classFqn: FqName): Collection<IrConstructorSymbol>
     fun referenceFunctions(fqName: FqName): Collection<IrSimpleFunctionSymbol>
     fun referenceProperties(fqName: FqName): Collection<IrPropertySymbol>
+
+    // temporary solution to load synthetic top-level declaration
+    fun referenceTopLevel(signature: IdSignature, kind: IrDeserializer.TopLevelSymbolKind, moduleDescriptor: ModuleDescriptor): IrSymbol?
 }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/extensions/IrPluginContextImpl.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.ir.declarations.IrConstructor
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.linkage.IrDeserializer
 import org.jetbrains.kotlin.ir.symbols.*
+import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.ir.util.IrMessageLogger
 import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
 import org.jetbrains.kotlin.ir.util.TypeTranslator
@@ -134,4 +135,14 @@ open class IrPluginContextImpl constructor(
             descriptors.map { st.referenceProperty(it) }
         }
     }
+
+    override fun referenceTopLevel(
+        signature: IdSignature,
+        kind: IrDeserializer.TopLevelSymbolKind,
+        moduleDescriptor: ModuleDescriptor
+    ): IrSymbol? {
+        val symbol = linker.resolveBySignatureInModule(signature, kind, moduleDescriptor.name)
+        linker.postProcess()
+        return symbol
+    }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/linkage/IrDeserializer.kt

@@ -9,6 +9,8 @@ import org.jetbrains.kotlin.ir.builders.TranslationPluginContext
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.name.Name
 
 interface IrDeserializer : IrProvider {
 
@@ -16,6 +18,14 @@ interface IrDeserializer : IrProvider {
         fun resolveSymbol(symbol: IrSymbol, context: TranslationPluginContext): IrDeclaration? = null
     }
 
+    enum class TopLevelSymbolKind {
+        FUNCTION_SYMBOL,
+        CLASS_SYMBOL,
+        PROPERTY_SYMBOL,
+        TYPEALIAS_SYMBOL;
+    }
+
     fun init(moduleFragment: IrModuleFragment?, extensions: Collection<IrLinkerExtension>) {}
+    fun resolveBySignatureInModule(signature: IdSignature, kind: TopLevelSymbolKind, moduleName: Name): IrSymbol
     fun postProcess() {}
 }

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/KotlinIrLinker.kt

@@ -34,6 +34,7 @@ import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.library.IrLibrary
 import org.jetbrains.kotlin.library.KotlinLibrary
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.protobuf.CodedInputStream
 import org.jetbrains.kotlin.protobuf.ExtensionRegistryLite.newInstance
 import org.jetbrains.kotlin.resolve.descriptorUtil.module
@@ -64,6 +65,7 @@ abstract class KotlinIrLinker(
 
     private val modulesWithReachableTopLevels = mutableSetOf<IrModuleDeserializer>()
 
+    // TODO: replace with Map<Name, IrModuleDeserializer>
     protected val deserializersForModules = mutableMapOf<ModuleDescriptor, IrModuleDeserializer>()
 
     abstract val fakeOverrideBuilder: FakeOverrideBuilder
@@ -665,6 +667,23 @@ abstract class KotlinIrLinker(
         // symbolTable.noUnboundLeft("unbound after fake overrides:")
     }
 
+    private fun topLevelKindToSymbolKind(kind: IrDeserializer.TopLevelSymbolKind): BinarySymbolData.SymbolKind {
+        return when (kind) {
+            IrDeserializer.TopLevelSymbolKind.CLASS_SYMBOL -> BinarySymbolData.SymbolKind.CLASS_SYMBOL
+            IrDeserializer.TopLevelSymbolKind.PROPERTY_SYMBOL -> BinarySymbolData.SymbolKind.PROPERTY_SYMBOL
+            IrDeserializer.TopLevelSymbolKind.FUNCTION_SYMBOL -> BinarySymbolData.SymbolKind.FUNCTION_SYMBOL
+            IrDeserializer.TopLevelSymbolKind.TYPEALIAS_SYMBOL -> BinarySymbolData.SymbolKind.TYPEALIAS_SYMBOL
+        }
+    }
+
+    override fun resolveBySignatureInModule(signature: IdSignature, kind: IrDeserializer.TopLevelSymbolKind, moduleName: Name): IrSymbol {
+        val moduleDeserializer =
+            deserializersForModules.entries.find { it.key.name == moduleName }?.value ?: error("No module for name '$moduleName' found")
+        assert(signature == signature.topLevelSignature()) { "Signature '$signature' has to be top level" }
+        if (signature !in moduleDeserializer) error("No signature $signature in module $moduleName")
+        return moduleDeserializer.deserializeIrSymbol(signature, topLevelKindToSymbolKind(kind))
+    }
+
     // The issue here is that an expect can not trigger its actual deserialization by reachability
     // because the expect can not see the actual higher in the module dependency dag.
     // So we force deserialization of actuals for all deserialized expect symbols here.