Kapt: dump declaration origins produced by backend

This will be useful in diagnosing behavior differences between JVM and
JVM_IR versions of kapt.

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/JvmDeclarationOrigin.kt

@@ -23,6 +23,9 @@ class JvmDeclarationOrigin(
     val descriptor: DeclarationDescriptor?,
     val parametersForJvmOverload: List<KtParameter?>? = null
 ) {
+    override fun toString(): String =
+        if (this == NO_ORIGIN) "NO_ORIGIN" else "origin=$originKind element=${element?.javaClass?.simpleName} descriptor=$descriptor"
+
     companion object {
         @JvmField
         val NO_ORIGIN: JvmDeclarationOrigin = JvmDeclarationOrigin(OTHER, null, null)

plugins/kapt3/kapt3-compiler/src/org/jetbrains/kotlin/kapt3/stubs/ClassFileToSourceStubConverter.kt

@@ -142,6 +142,10 @@ class ClassFileToSourceStubConverter(val kaptContext: KaptContextForStubGenerati
     private var done = false
 
     fun convert(): List<KaptStub> {
+        if (kaptContext.logger.isVerbose) {
+            dumpDeclarationOrigins()
+        }
+
         if (done) error(ClassFileToSourceStubConverter::class.java.simpleName + " can convert classes only once")
         done = true
 
@@ -154,6 +158,19 @@ class ClassFileToSourceStubConverter(val kaptContext: KaptContextForStubGenerati
         return stubs
     }
 
+    private fun dumpDeclarationOrigins() {
+        kaptContext.logger.info("Declaration origins:")
+        for ((key, value) in kaptContext.origins) {
+            val element = when (key) {
+                is ClassNode -> "class ${key.name}"
+                is FieldNode -> "field ${key.name}:${key.desc}"
+                is MethodNode -> "method ${key.name}${key.desc}"
+                else -> key.javaClass.toString()
+            }
+            kaptContext.logger.info("$element -> $value")
+        }
+    }
+
     private fun generateNonExistentClass(): JCCompilationUnit {
         val nonExistentClass = treeMaker.ClassDef(
             treeMaker.Modifiers((Flags.PUBLIC or Flags.FINAL).toLong()),