From 58ba5ed37b489a92c1deba4896974a1c4384de05 Mon Sep 17 00:00:00 2001
From: Michael Bogdanov <mikhael.bogdanov@jetbrains.com>
Date: Fri, 23 Sep 2016 15:01:06 +0300
Subject: [PATCH] Default args support

---
 .../kotlin/codegen/DefaultCallArgs.kt         | 14 ++++++++
 .../backend/jvm/codegen/ExpressionCodegen.kt  | 34 +++++++++++++------
 2 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/DefaultCallArgs.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/DefaultCallArgs.kt
index 184f8452f9d..321e6c7a319 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/DefaultCallArgs.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/DefaultCallArgs.kt
@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.codegen
 
 import org.jetbrains.kotlin.resolve.jvm.AsmTypes
 import org.jetbrains.org.objectweb.asm.Type
+import org.jetbrains.org.objectweb.asm.commons.InstructionAdapter
 import java.util.*
 
 class DefaultCallArgs(val size: Int) {
@@ -63,4 +64,17 @@ class DefaultCallArgs(val size: Int) {
         }
         return toInts.isNotEmpty()
     }
+
+    fun generateOnStackIfNeeded(iv: InstructionAdapter, isConstructor: Boolean): Boolean {
+        val toInts = toInts()
+        if (!toInts.isEmpty()) {
+            for (mask in toInts) {
+                iv.iconst(mask)
+            }
+
+            val parameterType = if (isConstructor) AsmTypes.DEFAULT_CONSTRUCTOR_MARKER else AsmTypes.OBJECT_TYPE
+            iv.aconst(null)
+        }
+        return toInts.isNotEmpty()
+    }
 }
\ No newline at end of file
diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt
index 0cdc031a164..20ed8623841 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt
@@ -20,8 +20,7 @@ import org.jetbrains.kotlin.backend.jvm.intrinsics.IrIntrinsicFunction
 import org.jetbrains.kotlin.backend.jvm.intrinsics.IrIntrinsicMethods
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.codegen.*
-import org.jetbrains.kotlin.codegen.AsmUtil.boxType
-import org.jetbrains.kotlin.codegen.AsmUtil.correctElementType
+import org.jetbrains.kotlin.codegen.AsmUtil.*
 import org.jetbrains.kotlin.codegen.StackValue.*
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.IrElement
@@ -158,19 +157,33 @@ class ExpressionCodegen(
             receiver?.apply {
                 gen(receiver, callable.owner, data)
             }
-            val args = (listOf(expression.extensionReceiver) +
+
+            val args = (listOf(expression.extensionReceiver).filterNotNull() +
                        expression.descriptor.valueParameters.mapIndexed { i, valueParameterDescriptor ->
-                           expression.getValueArgument(i)
-                       }).filterNotNull()
+                           expression.getValueArgument(i) ?: DefaultArg(i)
+                       })
+
+            val defaultMask = DefaultCallArgs(callable.valueParameterTypes.size)
             args.forEachIndexed { i, expression ->
-                gen(expression, callable.parameterTypes[i], data)
+                when (expression) {
+                    is IrExpression -> {
+                        gen(expression, callable.parameterTypes[i], data)
+                    }
+                    is DefaultArg -> {
+                        pushDefaultValueOnStack(callable.parameterTypes[i], mv)
+                        defaultMask.mark(expression.index)
+                    }
+                    else -> TODO()
+                }
             }
 
-            callable.genInvokeInstruction(mv)
+
+            if (!defaultMask.generateOnStackIfNeeded(mv, expression.descriptor is ConstructorDescriptor)) {
+                callable.genInvokeInstruction(mv)
+            } else {
+                (callable as CallableMethod).genInvokeDefaultInstruction(mv)
+            }
             return StackValue.onStack(callable.returnType)
-//            if (expression.descriptor !is ConstructorDescriptor) {
-//                //coerce(callable.returnType, expression.asmType, mv)
-//            }
         }
 
         return expression.onStack
@@ -421,3 +434,4 @@ class ExpressionCodegen(
         get() = typeMapper.mapType(this)
 }
 
+private class DefaultArg(val index: Int)