Mercurial > hg > truffle
view graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/InferStamps.java @ 14997:5e4ae8709830
Use typed illegal stamps and use IllegalStamp only for conflicting primitive types.
author | Roland Schatz <roland.schatz@oracle.com> |
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date | Fri, 04 Apr 2014 15:57:41 +0200 |
parents | e302df8bf51c |
children | 882f4cb7cfcf |
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/* * Copyright (c) 2013, 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.phases.graph; import com.oracle.graal.graph.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.spi.*; import com.oracle.graal.nodes.type.*; public class InferStamps { /** * Infer the stamps for all Object nodes in the graph, to make the stamps as precise as * possible. For example, this propagates the word-type through phi functions. To handle phi * functions at loop headers, the stamp inference is called until a fix point is reached. * <p> * This method can be used when it is needed that stamps are inferred before the first run of * the canonicalizer. For example, word type rewriting must run before the first run of the * canonicalizer because many nodes are not prepared to see the word type during * canonicalization. */ public static void inferStamps(StructuredGraph graph) { /* * We want to make the stamps more precise. For cyclic phi functions, this means we have to * ignore the initial stamp because the imprecise stamp would always propagate around the * cycle. We therefore set the stamp to an illegal stamp, which is automatically ignored * when the phi function performs the "meet" operator on its input stamps. */ for (Node n : graph.getNodes()) { if (n instanceof ValuePhiNode || n instanceof ValueAndStampProxy) { ValueNode node = (ValueNode) n; if (node.stamp() instanceof ObjectStamp) { assert node.stamp().isLegal() : "We assume all Phi and Proxy stamps are legal before the analysis"; node.setStamp(node.stamp().illegal()); } } } boolean stampChanged; do { stampChanged = false; /* * We could use GraphOrder.forwardGraph() to process the nodes in a defined order and * propagate long def-use chains in fewer iterations. However, measurements showed that * we have few iterations anyway, and the overhead of computing the order is much higher * than the benefit. */ for (Node n : graph.getNodes()) { if (n instanceof ValueNode) { ValueNode node = (ValueNode) n; if (node.stamp() instanceof ObjectStamp) { stampChanged |= node.inferStamp(); } } } } while (stampChanged); /* * Check that all the illegal stamps we introduced above are correctly replaced with real * stamps again. */ assert checkNoIllegalStamp(graph); } private static boolean checkNoIllegalStamp(StructuredGraph graph) { for (Node n : graph.getNodes()) { if (n instanceof ValuePhiNode || n instanceof ValueAndStampProxy) { ValueNode node = (ValueNode) n; assert !(node.stamp() instanceof IllegalStamp) : "Stamp is illegal after analysis. This is not necessarily an error, but a condition that we want to investigate (and then maybe relax or remove the assertion)."; } } return true; } }