Associate certain companion object fields with the parent class

smowton · smowton · commit a204c742d83c · 2022-05-27T11:52:39.000+01:00
Specifically `const`, `lateinit` and `@JvmField` properties get a static field which belongs to the containing class not the companion object, such that Java can address them via the containing class name rather than have to navigate a companion object pointer.
diff --git a/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt b/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
@@ -135,7 +135,7 @@ open class KotlinFileExtractor(
                     Unit
                 }
                 is IrField -> {
-                    val parentId = useDeclarationParent(declaration.parent, false)?.cast<DbReftype>()
+                    val parentId = useDeclarationParent(getFieldParent(declaration), false)?.cast<DbReftype>()
                     if (parentId != null) {
                         extractField(declaration, parentId)
                     }
@@ -829,10 +829,13 @@ open class KotlinFileExtractor(
                 }
 
                 if (bf != null && extractBackingField) {
-                    val fieldId = extractField(bf, parentId)
-                    tw.writeKtPropertyBackingFields(id, fieldId)
-                    if (p.isDelegated) {
-                        tw.writeKtPropertyDelegates(id, fieldId)
+                    val fieldParentId = useDeclarationParent(getFieldParent(bf), false)
+                    if (fieldParentId != null) {
+                        val fieldId = extractField(bf, fieldParentId.cast())
+                        tw.writeKtPropertyBackingFields(id, fieldId)
+                        if (p.isDelegated) {
+                            tw.writeKtPropertyDelegates(id, fieldId)
+                        }
                     }
                 }
 
diff --git a/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt b/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt
@@ -6,6 +6,7 @@ import com.semmle.extractor.java.OdasaOutput
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
 import org.jetbrains.kotlin.backend.common.ir.allOverridden
 import org.jetbrains.kotlin.backend.common.lower.parentsWithSelf
+import org.jetbrains.kotlin.backend.jvm.ir.getJvmNameFromAnnotation
 import org.jetbrains.kotlin.backend.jvm.ir.propertyIfAccessor
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.descriptors.*
@@ -1268,9 +1269,22 @@ open class KotlinUsesExtractor(
 
     fun useValueParameter(vp: IrValueParameter, parent: Label<out DbCallable>?): Label<out DbParam> =
         tw.getLabelFor(getValueParameterLabel(vp, parent))
+    fun isDirectlyExposedCompanionObjectField(f: IrField) =
+        f.hasAnnotation(FqName("kotlin.jvm.JvmField")) ||
+        f.correspondingPropertySymbol?.owner?.let {
+            it.isConst || it.isLateinit
+        } ?: false
+
+    fun getFieldParent(f: IrField) =
+        f.parentClassOrNull?.let {
+            if (it.isCompanion && isDirectlyExposedCompanionObjectField(f))
+                it.parent
+            else
+                null
+        } ?: f.parent
 
     fun getFieldLabel(f: IrField): String {
-        val parentId = useDeclarationParent(f.parent, false)
+        val parentId = useDeclarationParent(getFieldParent(f), false)
         return "@\"field;{$parentId};${f.name.asString()}\""
     }
 

Original file line number	Diff line number	Diff line change
`@@ -135,7 +135,7 @@ open class KotlinFileExtractor(`
`135`	`135`	`Unit`
`136`	`136`	`}`
`137`	`137`	`is IrField -> {`
`138`		`- val parentId = useDeclarationParent(declaration.parent, false)?.cast<DbReftype>()`
	`138`	`+ val parentId = useDeclarationParent(getFieldParent(declaration), false)?.cast<DbReftype>()`
`139`	`139`	`if (parentId != null) {`
`140`	`140`	`extractField(declaration, parentId)`
`141`	`141`	`}`
`@@ -829,10 +829,13 @@ open class KotlinFileExtractor(`
`829`	`829`	`}`
`830`	`830`
`831`	`831`	`if (bf != null && extractBackingField) {`
`832`		`- val fieldId = extractField(bf, parentId)`
`833`		`- tw.writeKtPropertyBackingFields(id, fieldId)`
`834`		`- if (p.isDelegated) {`
`835`		`- tw.writeKtPropertyDelegates(id, fieldId)`
	`832`	`+ val fieldParentId = useDeclarationParent(getFieldParent(bf), false)`
	`833`	`+ if (fieldParentId != null) {`
	`834`	`+ val fieldId = extractField(bf, fieldParentId.cast())`
	`835`	`+ tw.writeKtPropertyBackingFields(id, fieldId)`
	`836`	`+ if (p.isDelegated) {`
	`837`	`+ tw.writeKtPropertyDelegates(id, fieldId)`
	`838`	`+ }`
`836`	`839`	`}`
`837`	`840`	`}`
`838`	`841`