# HG changeset patch
# User Josef Eisl <josef.eisl@jku.at>
# Date 1397577303 -7200
# Node ID 257ec29335cffe572197180535ceff881656689a
# Parent  a775a766a3c80d25de9cb6ceef2b44fdfe9f5a06
BaselineCompiler: add basic loop support.

diff -r a775a766a3c8 -r 257ec29335cf graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/BaselineBytecodeParser.java
--- a/graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/BaselineBytecodeParser.java	Mon Apr 14 19:16:33 2014 +0200
+++ b/graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/BaselineBytecodeParser.java	Tue Apr 15 17:55:03 2014 +0200
@@ -121,7 +121,7 @@
             // add loops ? how do we add looks when we haven't parsed the bytecode?
 
             // create the control flow graph
-            LIRControlFlowGraph cfg = new LIRControlFlowGraph(blockMap.blocks.toArray(new BciBlock[0]), new ArrayList<Loop<BciBlock>>());
+            LIRControlFlowGraph cfg = new LIRControlFlowGraph(blockMap);
 
             BlocksToDoubles blockProbabilities = new BlocksToDoubles(blockMap.blocks.size());
             for (BciBlock b : blockMap.blocks) {
@@ -613,7 +613,7 @@
         }
 
         if (block.isLoopHeader) {
-            assert currentBlock.getId() >= block.getId() : "must be backward branch";
+            assert currentBlock == null || currentBlock.getId() >= block.getId() : "must be backward branch";
             if (currentBlock != null && currentBlock.numNormalSuccessors() == 1) {
                 // this is the only successor of the current block so we can adjust
                 adaptFramestate((LIRFrameStateBuilder) block.entryState);
diff -r a775a766a3c8 -r 257ec29335cf graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/LIRControlFlowGraph.java
--- a/graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/LIRControlFlowGraph.java	Mon Apr 14 19:16:33 2014 +0200
+++ b/graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/LIRControlFlowGraph.java	Tue Apr 15 17:55:03 2014 +0200
@@ -24,17 +24,21 @@
 
 import java.util.*;
 
+import com.oracle.graal.graph.*;
+import com.oracle.graal.java.*;
 import com.oracle.graal.java.BciBlockMapping.BciBlock;
 import com.oracle.graal.nodes.cfg.*;
 
 public class LIRControlFlowGraph implements AbstractControlFlowGraph<BciBlock> {
 
     private BciBlock[] blocks;
-    private List<Loop<BciBlock>> loops;
+    private Collection<Loop<BciBlock>> loops;
+    private BitSet visited;
 
-    public LIRControlFlowGraph(BciBlock[] blocks, List<Loop<BciBlock>> loops) {
-        this.blocks = blocks;
-        this.loops = loops;
+    public LIRControlFlowGraph(BciBlockMapping blockMap) {
+        blocks = blockMap.blocks.toArray(new BciBlock[0]);
+        loops = new ArrayList<>();
+        computeLoopInformation();
     }
 
     public BciBlock[] getBlocks() {
@@ -52,4 +56,44 @@
         return null;
     }
 
+    private void computeLoopInformation() {
+        visited = new BitSet(blocks.length);
+        Deque<LIRLoop> stack = new ArrayDeque<>();
+        for (int i = blocks.length - 1; i >= 0; i--) {
+            BciBlock block = blocks[i];
+            calcLoop(block, stack);
+        }
+    }
+
+    private void calcLoop(BciBlock block, Deque<LIRLoop> stack) {
+        if (visited.get(block.getId())) {
+            return;
+        }
+        visited.set(block.getId());
+        if (block.isLoopEnd()) {
+            BciBlock loopHeader = getLoopHeader(block);
+            LIRLoop l = new LIRLoop(stack.peek(), loops.size(), loopHeader);
+            loops.add(l);
+            stack.push(l);
+        }
+        block.loop = stack.peek();
+        if (block.isLoopHeader()) {
+            assert block.loop.header.equals(block);
+            stack.pop();
+        }
+        for (BciBlock pred : block.getPredecessors()) {
+            calcLoop(pred, stack);
+        }
+    }
+
+    private static BciBlock getLoopHeader(BciBlock block) {
+        assert block.isLoopEnd();
+        for (BciBlock sux : block.getSuccessors()) {
+            if (sux.isLoopHeader() && sux.getId() <= block.getId() && block.loops == sux.loops) {
+                return sux;
+            }
+        }
+        throw GraalInternalError.shouldNotReachHere("No loop header found for " + block);
+    }
+
 }
diff -r a775a766a3c8 -r 257ec29335cf graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/LIRLoop.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.baseline/src/com/oracle/graal/baseline/LIRLoop.java	Tue Apr 15 17:55:03 2014 +0200
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2014, 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.graal.baseline;
+
+import com.oracle.graal.java.BciBlockMapping.BciBlock;
+import com.oracle.graal.nodes.cfg.*;
+
+public class LIRLoop extends Loop<BciBlock> {
+
+    protected LIRLoop(Loop<BciBlock> parent, int index, BciBlock header) {
+        super(parent, index, header);
+    }
+
+    @Override
+    public long numBackedges() {
+        // currently only loops with one backedge are supported
+        return 1;
+    }
+
+}