Mercurial > hg > truffle
view graal/GraalCompiler/src/com/sun/c1x/graph/package-info.java @ 2609:a57e051b33cd
Move Graphviz visualization code to its own project, GraalGraphviz
author | Peter Hofer <peter.hofer@jku.at> |
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date | Mon, 09 May 2011 10:43:57 +0200 |
parents | 16b9a8b5ad39 |
children |
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/* * Copyright (c) 2010, 2011, 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. */ /** * <H2>IR Graph building</H2> * * The {@link com.sun.c1x.graph.IR} class drives the generation of the HIR graph for a method, making use of other * utility classes in this package. * * The graph building is separated into a basic build phase ({@link com.sun.c1x.graph.IR#buildGraph} method)and * (currently) two optimization phases ({@link com.sun.c1x.graph.IR#optimize1} and * {@link com.sun.c1x.graph.IR#optimize2}) although the basic phase also does some (basic) optimizations. * * <H2>Basic Graph Build Phase</H2> * * {@code IR.buildGraph} creates an {@link com.sun.c1x.ir.IRScope topScope} object, * that represents a context for inlining, and then invokes the constructor for the * {@link com.sun.c1x.graph.GraphBuilder} class, passing the {@link com.sun.c1x.C1XCompilation}, and {@code IR} * instances, which are cached. The following support objects are created in the constructor: * * <ul> * <li>{@code memoryMap}: an instance of {@link com.sun.c1x.graph.MemoryMap} * <li>{@code localValueMap}: an instance of {@link com.sun.c1x.opt.ValueMap} * <li>{@code canonicalizer}: an instance of {@link com.sun.c1x.opt.Canonicalizer} * </ul> * * Now the {@link com.sun.c1x.graph.GraphBuilder#build} is invoked with {@code topScope} as argument. * * <H3>{@code GraphBuilder.build}</H3> * * <ol> * <li>The {@link com.sun.c1x.graph.IR#startBlock} field of the cached {@link com.sun.c1x.graph.IR} instance is set to a newly created * {@link com.sun.c1x.ir.BlockBegin} node, with bytecode index 0 and then the {@link com.sun.c1x.graph.BlockMap} is * constructed by calling {@link com.sun.c1x.C1XCompilation#getBlockMap}. This behaves slightly differently depending on * whether this is an OSR compilation. If so, a new {@link com.sun.c1x.ir.BlockBegin} node is added to the map at the OSR bytecode * index. The map is then built by the{@link com.sun.c1x.graph.BlockMap#build}, which takes a boolean argument that * controls whether a second pass is made over the bytecodes to compute stores in loops. This always false for an OSR * compilation (why?). Otherwise, it is only true if enabled by the {@link com.sun.c1x.C1XOptions#PhiLoopStores} * compilation option. FInally some unneeded state from the map is removed by the {@link com.sun.c1x.graph.BlockMap#cleanup} method, and * the statistics are updated. * </li> * * <li>Next the {@link com.sun.c1x.graph.GraphBuilder#pushRootScope} method is called, with the passed-in {@link com.sun.c1x.ir.IRScope} * object, the {@link com.sun.c1x.graph.BlockMap} returned by build and the {@code startBlock}. (Note: Unlike * {@link com.sun.c1x.graph.GraphBuilder#pushScope}, this method does not propagate the * {@link com.sun.c1x.graph.BlockMap#storesInLoops} field to the {@link com.sun.c1x.ir.IRScope} object, which means that * {@link com.sun.c1x.ir.BlockBegin#insertLoopPhis} will always get null for this value. Is this a bug?). * {@link com.sun.c1x.graph.GraphBuilder#pushRootScope} initializes the {@link com.sun.c1x.graph.GraphBuilder#scopeData} field with a * {@link com.sun.c1x.graph.ScopeData} instance, with null parent. The * {@link com.sun.c1x.graph.GraphBuilder#compilation} instance is called to get an {@link com.sun.cri.ri.RiConstantPool} * , which is C1X's interface to constant pool information. The {@link com.sun.c1x.graph.GraphBuilder#curBlock} field is * set to the {@code startBlock}. * <p> * * Now a {@link com.sun.c1x.value.FrameState initialState} object is created by * {@link com.sun.c1x.graph.GraphBuilder#stateAtEntry}. If the method is not static, then a {@link com.sun.c1x.ir.Local} * instance is created at index 0. Since the receiver cannot be {@code null}, the * {@link com.sun.c1x.ir.Value.Flag#NonNull} flag is set. Additional {@link com.sun.c1x.ir.Local} instances are created for the * arguments to the method. The index is incremented by the number of slots occupied by the * {@link com.sun.cri.ci.CiKind} corresponding to the argument type. All the {@link com.sun.c1x.ir.Local} instances are stored in the * {@link com.sun.c1x.value.FrameState} using the {@link com.sun.c1x.value.FrameState#storeLocal} method. This {@link com.sun.c1x.value.FrameState} is then * merged into the {@link com.sun.c1x.ir.BlockBegin#stateBefore} for the {@code startBlock}, which just results in a * copy since {@code stateBefore} will be {@code null}. * </li> * <li> * This step sets up three instance fields: {@link com.sun.c1x.graph.GraphBuilder#curBlock} and * {@link com.sun.c1x.graph.GraphBuilder#lastInstr} to {@code startBlock} and * {@link com.sun.c1x.graph.GraphBuilder#curState} to {@code initialState}. (N.B. the setting of {@code curBlock} is * redundant as it is done in {@link com.sun.c1x.graph.GraphBuilder#pushRootScope}). * </li> * <li> * Step 4 contains special handling for synchronized methods (TBD), otherwise it calls * {@link com.sun.c1x.graph.GraphBuilder#finishStartBlock} which adds a {@link com.sun.c1x.ir.Base} block as the end of * the {@code startBlock}. The {@link com.sun.c1x.ir.Base} block has one successor set to the (entry) block with flag * {@link com.sun.c1x.ir.BlockBegin.BlockFlag#StandardEntry}, that was created by {@link com.sun.c1x.graph.BlockMap#build} (and possibly a * successor to an OSREntry block). * </li> * <li> * Then the {@link com.sun.c1x.ir.IRScope#lockStackSize} is computed. (TBD) * </li> * <li> * Then the method is checked for being intrinsic, i.e., one that has a hard-wired implementation known to C1X. If so, * and {@link com.sun.c1x.C1XOptions#OptIntrinsify} is set, an attempt is made to inline it (TBD). Otherwise, or if the * intrinsification fails, normal processing continues by adding the entry block to the * {@link com.sun.c1x.graph.ScopeData} work list (kept topologically sorted) and calling * {@link com.sun.c1x.graph.GraphBuilder#iterateAllBlocks}. * </li> * <li> * Finally there is some cleanup code for synchronized blocks and OSR compilations. * </li> * </ol> * * <H3>{@link com.sun.c1x.graph.GraphBuilder#iterateAllBlocks}</H3> * {@link com.sun.c1x.graph#iterateAllBlocks} repeatedly removes a block from the work list and, if not already visited, marks it so, * kills the current memory map, sets {@link com.sun.c1x.graph.GraphBuilder#curBlock}, {@link com.sun.c1x.graph.GraphBuilder#curState} and {@link com.sun.c1x.graph.GraphBuilder#lastInstr} and then calls * {@link com.sun.c1x.graph.GraphBuilder#iterateBytecodesForBlock}. * * This process continues until all the blocks have been visited (processed) after which control returns to {@code * build}. * <p> * <H3>{@link com.sun.c1x.graph.GraphBuilder#iterateBytecodesForBlock}</H3> * * {@link com.sun.c1x.graph.GraphBuilder#iterateBytecodesForBlock} performs an abstract interpretation of the bytecodes in the block, appending new * nodes as necessary, until the last added node is an instance of {@link com.sun.c1x.ir.BlockEnd}. (Note: It has an * explicit check for finding a new {@link com.sun.c1x.ir.BlockBegin} before a {@link com.sun.c1x.ir.BlockEnd} but * {@link com.sun.c1x.graph.BlockMap#moveSuccessorLists} has a similar check so this may be redundant). For example, * consider the following bytecodes: * * <pre> * <code> * 0: iconst_0 * 1: istore_2 * 2: goto 22 * </code> * </pre> * * The {@code iconst_0} bytecode causes a {@link com.sun.c1x.ir.Constant} node representing zero to be pushed on the * {@link com.sun.c1x.graph.GraphBuilder#curState} stack and the node to be appended to the {@link com.sun.c1x.ir.BlockBegin} (entry) node associated with index 0. * The {@code istore_2} causes the node to be popped of the stack and stored in the local slot 2. No IR node is * generated for the {@code istore_2}. The {@code goto} creates a {@link com.sun.c1x.ir.Goto} node which is a subclass * of {@link com.sun.c1x.ir.BlockEnd}, so this terminates the iteration. As part of termination the {@link com.sun.c1x.ir.Goto} node is marked as the * end node of the current block and the {@link com.sun.c1x.value.FrameState} is propagated to the successor node(s) by merging any * existing {@link com.sun.c1x.value.FrameState} with the current state. If the target is a loop header node this involves inserting * {@link com.sun.c1x.ir.Phi} nodes. Finally, the target node is added to the {@code scopeData} work list. * <p> * * * @author Ben Titzer * @author Mick Jordan * */ package com.sun.c1x.graph;