From 3324527984006ad507644637f86100fae9af2f8b Mon Sep 17 00:00:00 2001
From: Svyatoslav Scherbina <svyatoslav.scherbina@jetbrains.com>
Date: Tue, 4 Oct 2016 13:55:03 +0300
Subject: [PATCH] backend.native, runtime: add vtable to TypeInfo

---
 .../kotlin/backend/native/llvm/LlvmUtils.kt   |  1 +
 .../backend/native/llvm/RTTIGenerator.kt      | 40 +++++++++++++++++--
 runtime/src/main/cpp/TypeInfo.h               |  1 +
 3 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/LlvmUtils.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/LlvmUtils.kt
index f3ab701e56b..f79a90b5681 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/LlvmUtils.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/LlvmUtils.kt
@@ -55,6 +55,7 @@ internal fun compileTimeValue(value: LLVMOpaqueValue?) = object : CompileTimeVal
     override fun getLlvmValue() = value
 }
 
+internal val int8Type = LLVMInt8Type()
 internal val int32Type = LLVMInt32Type()
 
 internal fun pointerType(pointeeType: LLVMOpaqueType?) = LLVMPointerType(pointeeType, 0)
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/RTTIGenerator.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/RTTIGenerator.kt
index 2d56e0346cb..a7ff4e1ee29 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/RTTIGenerator.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/native/llvm/RTTIGenerator.kt
@@ -6,10 +6,9 @@ import llvm.*
 import org.jetbrains.kotlin.backend.native.implementation
 import org.jetbrains.kotlin.backend.native.implementedInterfaces
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.descriptors.FunctionDescriptor
-import org.jetbrains.kotlin.descriptors.PropertyDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.resolve.OverridingUtil
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassOrAny
 
@@ -32,6 +31,7 @@ internal class RTTIGenerator(override val context: Context) : ContextUtils {
                                  val objOffsetsCount: Int,
                                  val interfaces: CompileTimeValue,
                                  val interfacesCount: Int,
+                                 val vtable: CompileTimeValue,
                                  val methods: CompileTimeValue,
                                  val methodsCount: Int,
                                  val fields: CompileTimeValue,
@@ -50,6 +50,8 @@ internal class RTTIGenerator(override val context: Context) : ContextUtils {
                     interfaces,
                     Int32(interfacesCount),
 
+                    vtable,
+
                     methods,
                     Int32(methodsCount),
 
@@ -71,6 +73,33 @@ internal class RTTIGenerator(override val context: Context) : ContextUtils {
         return classType
     }
 
+    // TODO: optimize
+    private fun getVtableEntries(classDesc: ClassDescriptor): List<FunctionDescriptor> {
+        val superVtableEntries = if (KotlinBuiltIns.isAny(classDesc)) {
+            emptyList()
+        } else {
+            getVtableEntries(classDesc.getSuperClassOrAny())
+        }
+
+        val inheritedVtableSlots = Array<FunctionDescriptor?>(superVtableEntries.size, { null })
+        val methods = getMethodTableEntries(classDesc) // TODO: ensure order is well-defined
+        val entriesForNewVtableSlots = methods.toMutableSet()
+
+        methods.forEach { method ->
+            superVtableEntries.forEachIndexed { i, superMethod ->
+                if (OverridingUtil.overrides(method, superMethod)) {
+                    assert (inheritedVtableSlots[i] == null)
+                    inheritedVtableSlots[i] = method
+
+                    assert (method in entriesForNewVtableSlots)
+                    entriesForNewVtableSlots.remove(method)
+                }
+            }
+        }
+
+        return inheritedVtableSlots.map { it!! } + methods.filter { it in entriesForNewVtableSlots }
+    }
+
     private fun getMethodTableEntries(classDesc: ClassDescriptor): List<FunctionDescriptor> {
         val contributedDescriptors = classDesc.unsubstitutedMemberScope.getContributedDescriptors()
          // (includes declarations from supers)
@@ -120,6 +149,10 @@ internal class RTTIGenerator(override val context: Context) : ContextUtils {
 
         val fieldsPtr = addGlobalConstArray("kfields:$className", runtime.fieldTableRecordType, fields)
 
+        // TODO: compile-time resolution limits binary compatibility
+        val vtable = getVtableEntries(classDesc).map { it.implementation.entryPointAddress }
+        val vtablePtr = addGlobalConstArray("kvtable:$className", pointerType(int8Type), vtable)
+
         val methods = getMethodTableEntries(classDesc).map {
             val nameSignature = it.name.nameHash // FIXME: add signature
             // TODO: compile-time resolution limits binary compatibility
@@ -133,6 +166,7 @@ internal class RTTIGenerator(override val context: Context) : ContextUtils {
                                 superType,
                                 objOffsetsPtr, objOffsets.size,
                                 interfacesPtr, interfaces.size,
+                                vtablePtr,
                                 methodsPtr, methods.size,
                                 fieldsPtr, fields.size)
 
diff --git a/runtime/src/main/cpp/TypeInfo.h b/runtime/src/main/cpp/TypeInfo.h
index 8df39fa4705..feea599a316 100644
--- a/runtime/src/main/cpp/TypeInfo.h
+++ b/runtime/src/main/cpp/TypeInfo.h
@@ -29,6 +29,7 @@ struct TypeInfo {
     int objOffsetsCount;
     TypeInfo* const* implementedInterfaces;
     int implementedInterfacesCount;
+    void* const* vtable; // TODO: place vtable at the end of TypeInfo to eliminate the indirection
     const MethodTableRecord* methods;
     int methodsCount;
     const FieldTableRecord* fields;