Create simple stack model for interpreter

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Stack.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.common.interpreter.stack
+
+interface Stack {
+    fun pushFrame(frame: Frame)
+    fun popFrame(): Frame
+    fun peekFrame(): Frame
+}
+
+interface Frame {
+    fun addVar(state: State)
+    fun getVar(name: String): State
+}

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/StackImpl.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.common.interpreter.stack
+
+import java.util.NoSuchElementException
+
+class StackImpl : Stack {
+    private val stack: MutableList<Frame> = mutableListOf()
+
+    override fun pushFrame(frame: Frame) {
+        stack.add(frame)
+    }
+
+    override fun popFrame(): Frame {
+        if (stack.isEmpty()) {
+            throw IndexOutOfBoundsException("Stack is empty")
+        }
+        return stack.removeAt(stack.size - 1)
+    }
+
+    override fun peekFrame(): Frame {
+        if (stack.isEmpty()) {
+            throw IndexOutOfBoundsException("Stack is empty")
+        }
+        return stack.get(stack.size - 1)
+    }
+}
+
+class InterpreterFrame : Frame {
+    val pool: MutableList<State> = mutableListOf()
+
+    override fun addVar(state: State) {
+        pool.add(state)
+    }
+
+    override fun getVar(name: String): State {
+        return pool.firstOrNull { it.getName() == name }
+            ?: throw NoSuchElementException("Frame pool doesn't contains variable with name $name")
+    }
+}

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/State.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.common.interpreter.stack
+
+import org.jetbrains.kotlin.ir.expressions.IrConst
+
+interface State {
+    fun getState(): List<State>
+    fun getName(): String
+}
+
+class Primitive<T>(public val varName: String, public val value: IrConst<T>) : State {
+    override fun getState(): List<State> {
+        return listOf(this)
+    }
+
+    override fun getName(): String {
+        return varName
+    }
+}
+class Complex(public val objName: String, public val values: List<State>) : State {
+    override fun getState(): List<State> {
+        return values
+    }
+
+    override fun getName(): String {
+        return objName
+    }
+}