1 /*
2 * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package org.graalvm.compiler.hotspot.stubs;
24
25 import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_VMCONFIG;
26 import static org.graalvm.compiler.hotspot.nodes.JumpToExceptionHandlerNode.jumpToExceptionHandler;
27 import static org.graalvm.compiler.hotspot.nodes.PatchReturnAddressNode.patchReturnAddress;
28 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.readExceptionOop;
29 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.readExceptionPc;
30 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.registerAsWord;
31 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.writeExceptionOop;
32 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.writeExceptionPc;
33 import static org.graalvm.compiler.hotspot.stubs.StubUtil.cAssertionsEnabled;
34 import static org.graalvm.compiler.hotspot.stubs.StubUtil.decipher;
35 import static org.graalvm.compiler.hotspot.stubs.StubUtil.fatal;
36 import static org.graalvm.compiler.hotspot.stubs.StubUtil.newDescriptor;
37 import static org.graalvm.compiler.hotspot.stubs.StubUtil.printf;
38
39 import org.graalvm.compiler.api.replacements.Fold;
40 import org.graalvm.compiler.api.replacements.Fold.InjectedParameter;
41 import org.graalvm.compiler.api.replacements.Snippet;
42 import org.graalvm.compiler.api.replacements.Snippet.ConstantParameter;
43 import org.graalvm.compiler.core.common.spi.ForeignCallDescriptor;
44 import org.graalvm.compiler.graph.Node.ConstantNodeParameter;
45 import org.graalvm.compiler.graph.Node.NodeIntrinsic;
46 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
47 import org.graalvm.compiler.hotspot.HotSpotBackend;
48 import org.graalvm.compiler.hotspot.HotSpotForeignCallLinkage;
49 import org.graalvm.compiler.hotspot.meta.HotSpotProviders;
50 import org.graalvm.compiler.hotspot.nodes.StubForeignCallNode;
51 import org.graalvm.compiler.word.Word;
52
53 import jdk.vm.ci.code.Register;
54
55 /**
56 * Stub called by the {@linkplain GraalHotSpotVMConfig#MARKID_EXCEPTION_HANDLER_ENTRY exception
57 * handler entry point} in a compiled method. This entry point is used when returning to a method to
58 * handle an exception thrown by a callee. It is not used for routing implicit exceptions.
59 * Therefore, it does not need to save any registers as HotSpot uses a caller save convention.
60 * <p>
61 * The descriptor for a call to this stub is {@link HotSpotBackend#EXCEPTION_HANDLER}.
62 */
63 public class ExceptionHandlerStub extends SnippetStub {
64
65 public ExceptionHandlerStub(HotSpotProviders providers, HotSpotForeignCallLinkage linkage) {
66 super("exceptionHandler", providers, linkage);
67 }
68
69 /**
70 * This stub is called when returning to a method to handle an exception thrown by a callee. It
71 * is not used for routing implicit exceptions. Therefore, it does not need to save any
72 * registers as HotSpot uses a caller save convention.
73 */
74 @Override
75 public boolean preservesRegisters() {
76 return false;
77 }
78
79 @Override
80 protected Object getConstantParameterValue(int index, String name) {
81 assert index == 2;
82 return providers.getRegisters().getThreadRegister();
83 }
84
85 @Snippet
86 private static void exceptionHandler(Object exception, Word exceptionPc, @ConstantParameter Register threadRegister) {
87 Word thread = registerAsWord(threadRegister);
88 checkNoExceptionInThread(thread, assertionsEnabled(INJECTED_VMCONFIG));
89 checkExceptionNotNull(assertionsEnabled(INJECTED_VMCONFIG), exception);
90 writeExceptionOop(thread, exception);
91 writeExceptionPc(thread, exceptionPc);
92 if (logging()) {
93 printf("handling exception %p (", Word.objectToTrackedPointer(exception).rawValue());
94 decipher(Word.objectToTrackedPointer(exception).rawValue());
95 printf(") at %p (", exceptionPc.rawValue());
96 decipher(exceptionPc.rawValue());
97 printf(")\n");
98 }
99
100 // patch throwing pc into return address so that deoptimization finds the right debug info
101 patchReturnAddress(exceptionPc);
102
103 Word handlerPc = exceptionHandlerForPc(EXCEPTION_HANDLER_FOR_PC, thread);
104
105 if (logging()) {
106 printf("handler for exception %p at %p is at %p (", Word.objectToTrackedPointer(exception).rawValue(), exceptionPc.rawValue(), handlerPc.rawValue());
107 decipher(handlerPc.rawValue());
108 printf(")\n");
109 }
110
111 // patch the return address so that this stub returns to the exception handler
112 jumpToExceptionHandler(handlerPc);
113 }
114
115 static void checkNoExceptionInThread(Word thread, boolean enabled) {
116 if (enabled) {
117 Object currentException = readExceptionOop(thread);
118 if (currentException != null) {
119 fatal("exception object in thread must be null, not %p", Word.objectToTrackedPointer(currentException).rawValue());
120 }
121 if (cAssertionsEnabled(INJECTED_VMCONFIG)) {
122 // This thread-local is only cleared in DEBUG builds of the VM
123 // (see OptoRuntime::generate_exception_blob)
124 Word currentExceptionPc = readExceptionPc(thread);
125 if (currentExceptionPc.notEqual(Word.zero())) {
126 fatal("exception PC in thread must be zero, not %p", currentExceptionPc.rawValue());
127 }
128 }
129 }
130 }
131
132 static void checkExceptionNotNull(boolean enabled, Object exception) {
133 if (enabled && exception == null) {
134 fatal("exception must not be null");
135 }
136 }
137
138 @Fold
139 static boolean logging() {
140 return StubOptions.TraceExceptionHandlerStub.getValue();
141 }
142
143 /**
144 * Determines if either Java assertions are enabled for {@link ExceptionHandlerStub} or if this
145 * is a HotSpot build where the ASSERT mechanism is enabled.
146 * <p>
147 * This first check relies on the per-class assertion status which is why this method must be in
148 * this class.
149 */
150 @Fold
151 @SuppressWarnings("all")
152 static boolean assertionsEnabled(@InjectedParameter GraalHotSpotVMConfig config) {
153 boolean enabled = false;
154 assert enabled = true;
155 return enabled || cAssertionsEnabled(config);
156 }
157
158 public static final ForeignCallDescriptor EXCEPTION_HANDLER_FOR_PC = newDescriptor(ExceptionHandlerStub.class, "exceptionHandlerForPc", Word.class, Word.class);
159
160 @NodeIntrinsic(value = StubForeignCallNode.class, setStampFromReturnType = true)
161 public static native Word exceptionHandlerForPc(@ConstantNodeParameter ForeignCallDescriptor exceptionHandlerForPc, Word thread);
162 }