From ae96afb1dc4e109738424f4cd6f61798681e51e2 Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <Mikhail.Glukhikh@jetbrains.com>
Date: Fri, 23 Sep 2016 19:42:11 +0300
Subject: [PATCH] CFG: function builder

---
 .../ir2cfg/generators/FunctionBuilder.kt      | 110 ++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionBuilder.kt

diff --git a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionBuilder.kt b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionBuilder.kt
new file mode 100644
index 00000000000..703ebcd4193
--- /dev/null
+++ b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionBuilder.kt
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2010-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.ir2cfg.generators
+
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.declarations.IrFunction
+import org.jetbrains.kotlin.ir2cfg.builders.BasicBlockBuilder
+import org.jetbrains.kotlin.ir2cfg.builders.BlockConnectorBuilder
+import org.jetbrains.kotlin.ir2cfg.builders.ControlFlowGraphBuilder
+import org.jetbrains.kotlin.ir2cfg.graph.BasicBlock
+import org.jetbrains.kotlin.ir2cfg.graph.BlockConnector
+import org.jetbrains.kotlin.ir2cfg.graph.ControlFlowGraph
+
+class FunctionBuilder(val function: IrFunction)  : ControlFlowGraphBuilder {
+
+    private val blockBuilderMap = mutableMapOf<IrElement, BasicBlockBuilder>()
+
+    private var currentBlockBuilder: BasicBlockBuilder? = null
+
+    private val blocks = mutableListOf<BasicBlock>()
+
+    private val connectorBuilderMap = mutableMapOf<IrElement, BlockConnectorBuilder>()
+
+    private fun createBlockBuilder(after: BlockConnectorBuilder?): BasicBlockBuilder {
+        val result = GeneralBlockBuilder(after)
+        currentBlockBuilder = result
+        return result
+    }
+
+    private fun BasicBlockBuilder.shiftTo(element: IrElement) {
+        blockBuilderMap.remove(last)
+        add(element)
+        blockBuilderMap[element] = this
+    }
+
+    override fun add(element: IrElement) {
+        val blockBuilder = currentBlockBuilder ?: createBlockBuilder(connectorBuilderMap[element])
+        blockBuilder.shiftTo(element)
+    }
+
+    override fun move(to: IrElement) {
+        val blockBuilder = blockBuilderMap[to]
+                           ?: connectorBuilderMap[to]?.let { createBlockBuilder(it) }
+                           ?: throw AssertionError("Function generator may move to an element only to the end of a block or to connector")
+        currentBlockBuilder = blockBuilder
+    }
+
+    override fun jump(to: IrElement) {
+        val blockBuilder = currentBlockBuilder
+                           ?: throw AssertionError("Function generator: no default block builder for jump")
+        val block = blockBuilder.build()
+        blocks.add(block)
+        blockBuilderMap.values.remove(blockBuilder)
+        currentBlockBuilder = null
+        val nextConnectorBuilder = connectorBuilderMap[to] ?: GeneralConnectorBuilder(to)
+        nextConnectorBuilder.addPrevious(block)
+        val previousConnectorBuilder = blockBuilder.incoming
+        previousConnectorBuilder?.addNext(block)
+        connectorBuilderMap[to] = nextConnectorBuilder
+        move(to)
+    }
+
+    override fun jump(to: IrElement, from: IrElement) {
+        currentBlockBuilder = blockBuilderMap[from]
+        if (currentBlockBuilder == null) {
+            val blockBuilder = connectorBuilderMap[from]?.let { createBlockBuilder(it) }
+                               ?: throw AssertionError("Function generator may jump after an element only to the end of a block or to connector")
+            currentBlockBuilder = blockBuilder
+        }
+        jump(to)
+    }
+
+    override fun build(): ControlFlowGraph {
+        for (blockBuilder in blockBuilderMap.values) {
+            if (currentBlockBuilder == blockBuilder) {
+                currentBlockBuilder = null
+            }
+            val block = blockBuilder.build()
+            blocks.add(block)
+            blockBuilder.incoming?.addNext(block)
+        }
+        val connectors = mutableListOf<BlockConnector>()
+        for (connectorBuilder in connectorBuilderMap.values) {
+            connectors.add(connectorBuilder.build())
+        }
+        for (connector in connectors) {
+            for (previous in connector.previousBlocks) {
+                (previous as? BasicBlockImpl)?.outgoing = connector
+            }
+            for (next in connector.nextBlocks) {
+                (next as? BasicBlockImpl)?.incoming = connector
+            }
+        }
+        return ControlFlowGraphImpl(function, blocks, connectors)
+    }
+}