[FIR] Extract FirPluginKey into :core:compiler.common and rename it to GeneratedDeclarationKey

This is needed to avoid dependency on :compiler:fir:fir2ir module in
  backend parts of compiler plugins. It will allow to publish those
  parts into jars for IDE, where they are needed for working of debugger
  and bytecode toolwindow

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrDeclarationOrigin.kt

@@ -5,6 +5,8 @@
 
 package org.jetbrains.kotlin.ir.declarations
 
+import org.jetbrains.kotlin.GeneratedDeclarationKey
+
 interface IrDeclarationOrigin {
     object DEFINED : IrDeclarationOriginImpl("DEFINED")
     object FAKE_OVERRIDE : IrDeclarationOriginImpl("FAKE_OVERRIDE")
@@ -78,6 +80,22 @@ interface IrDeclarationOrigin {
 
     object SHARED_VARIABLE_IN_EVALUATOR_FRAGMENT : IrDeclarationOriginImpl("SHARED_VARIABLE_IN_EVALUATOR_FRAGMENT", isSynthetic = true)
 
+    class GeneratedByPlugin(val pluginKey: GeneratedDeclarationKey) : IrDeclarationOrigin {
+        override fun toString(): String {
+            return "GENERATED[${pluginKey}]"
+        }
+
+        override fun equals(other: Any?): Boolean {
+            if (this === other) return true
+            if (other !is GeneratedByPlugin) return false
+            return pluginKey == other.pluginKey
+        }
+
+        override fun hashCode(): Int {
+            return pluginKey.hashCode()
+        }
+    }
+
     val isSynthetic: Boolean get() = false
 }
 

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

@@ -771,7 +771,7 @@ class IrDeclarationDeserializer(
     companion object {
         private val allKnownDeclarationOrigins = IrDeclarationOrigin::class.nestedClasses.toList()
         private val declarationOriginIndex =
-            allKnownDeclarationOrigins.map { it.objectInstance as IrDeclarationOriginImpl }.associateBy { it.name }
+            allKnownDeclarationOrigins.mapNotNull { it.objectInstance as? IrDeclarationOriginImpl }.associateBy { it.name }
     }
 
     private fun deserializeIrDeclarationOrigin(protoName: Int): IrDeclarationOriginImpl {
@@ -821,4 +821,4 @@ class IrDeclarationDeserializer(
             else -> false
         }
     }
-}
+}