1/*
2 * Copyright (c) 2016, 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
24package jdk.tools.jaotc;
25
26import jdk.tools.jaotc.binformat.BinaryContainer;
27import jdk.tools.jaotc.binformat.Symbol;
28import jdk.tools.jaotc.CompiledMethodInfo.StubInformation;
29
30import jdk.vm.ci.code.site.Call;
31import jdk.vm.ci.hotspot.HotSpotResolvedJavaMethod;
32
33/**
34 * Symbol for a regular Java call. This method also creates additional relocations for {@code .plt}
35 * to {@code .got} and {@code .got} to {@code .plt}.
36 */
37final class JavaCallSiteRelocationSymbol extends CallSiteRelocationSymbol {
38
39    private static final byte[] zeroSlot = new byte[8];
40    // -1 represents Universe::non_oop_word() value
41    private static final byte[] minusOneSlot = {-1, -1, -1, -1, -1, -1, -1, -1};
42
43    public JavaCallSiteRelocationSymbol(CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation, BinaryContainer binaryContainer) {
44        super(createPltEntrySymbol(binaryContainer, mi, call, callSiteRelocation));
45        StubInformation stub = getStub(mi, call);
46        addRelocations(mi, stub, binaryContainer, call, callSiteRelocation);
47    }
48
49    /**
50     * Returns a unique symbol name with the {@code suffix} appended.
51     */
52    private static String relocationSymbolName(String suffix, CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation) {
53        return "M" + mi.getCodeId() + "_" + call.pcOffset + "_" + callSiteRelocation.targetSymbol + "_" + suffix;
54    }
55
56    private static Symbol createPltEntrySymbol(BinaryContainer binaryContainer, CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation) {
57        String symbolName = relocationSymbolName("plt.entry", mi, call, callSiteRelocation);
58        StubInformation stub = getStub(mi, call);
59        return createCodeContainerSymbol(binaryContainer, symbolName, stub.getOffset());
60    }
61
62    private static StubInformation getStub(CompiledMethodInfo mi, Call call) {
63        HotSpotResolvedJavaMethod callTarget = (HotSpotResolvedJavaMethod) call.target;
64        String callTargetSymbol = MiscUtils.uniqueMethodName(callTarget) + ".at." + call.pcOffset;
65        return mi.getStubFor(callTargetSymbol);
66    }
67
68    /**
69     * Add all the required relocations.
70     */
71    private static void addRelocations(CompiledMethodInfo mi, StubInformation stub, BinaryContainer binaryContainer, Call call, CallSiteRelocationInfo callSiteRelocation) {
72        final boolean isVirtualCall = MiscUtils.isVirtualCall(mi, call);
73
74        final int gotStartOffset = binaryContainer.appendExtLinkageGotBytes(zeroSlot, 0, zeroSlot.length);
75        if (isVirtualCall) {
76            // Nothing.
77        } else {
78            // For c2i stub we need slot with -1 value.
79            binaryContainer.appendExtLinkageGotBytes(minusOneSlot, 0, minusOneSlot.length);
80        }
81
82        // Add relocation to GOT cell for call resolution jump.
83        // This GOT cell will be initialized during JVM startup with address
84        // of JVM runtime call resolution function.
85        String gotSymbolName = "got." + getResolveSymbolName(binaryContainer, mi, call);
86        Symbol gotSymbol = binaryContainer.getGotSymbol(gotSymbolName);
87        addExternalPltToGotRelocation(binaryContainer, gotSymbol, stub.getResolveJumpOffset());
88
89        // Add relocation to resolve call jump instruction address for GOT cell.
90        // This GOT cell will be initialized with address of resolution jump instruction and
91        // will be updated with call destination address by JVM runtime call resolution code.
92        String pltJmpSymbolName = relocationSymbolName("plt.jmp", mi, call, callSiteRelocation);
93        addCodeContainerRelocation(binaryContainer, pltJmpSymbolName, stub.getResolveJumpStart(), gotStartOffset);
94
95        // Add relocation to GOT cell for dispatch jump.
96        // The dispatch jump loads destination address from this GOT cell.
97        String gotEntrySymbolName = relocationSymbolName("got.entry", mi, call, callSiteRelocation);
98        addExtLinkageGotContainerRelocation(binaryContainer, gotEntrySymbolName, gotStartOffset, stub.getDispatchJumpOffset());
99
100        // Virtual call needs initial -1 value for Klass pointer.
101        // Non virtual call needs initial 0 value for Method pointer to call c2i adapter.
102        byte[] slot = isVirtualCall ? minusOneSlot : zeroSlot;
103        final int gotMetaOffset = binaryContainer.appendExtLinkageGotBytes(slot, 0, slot.length);
104
105        // Add relocation to GOT cell for move instruction (Klass* for virtual, Method* otherwise).
106        String gotMoveSymbolName = relocationSymbolName("got.move", mi, call, callSiteRelocation);
107        addExtLinkageGotContainerRelocation(binaryContainer, gotMoveSymbolName, gotMetaOffset, stub.getMovOffset());
108
109        if (isVirtualCall) {
110            // Nothing.
111        } else {
112            // Add relocation to GOT cell for c2i adapter jump.
113            // The c2i jump instruction loads destination address from this GOT cell.
114            // This GOT cell is initialized with -1 and will be updated
115            // by JVM runtime call resolution code.
116            String gotC2ISymbolName = relocationSymbolName("got.c2i", mi, call, callSiteRelocation);
117            addExtLinkageGotContainerRelocation(binaryContainer, gotC2ISymbolName, gotStartOffset + 8, stub.getC2IJumpOffset());
118        }
119    }
120
121    /**
122     * Returns the name of the resolve method for this particular call.
123     */
124    private static String getResolveSymbolName(BinaryContainer binaryContainer, CompiledMethodInfo mi, Call call) {
125        String resolveSymbolName;
126        if (MiscUtils.isStaticCall(call)) {
127            resolveSymbolName = binaryContainer.getResolveStaticEntrySymbolName();
128        } else if (MiscUtils.isSpecialCall(call)) {
129            resolveSymbolName = binaryContainer.getResolveOptVirtualEntrySymbolName();
130        } else if (MiscUtils.isOptVirtualCall(mi, call)) {
131            resolveSymbolName = binaryContainer.getResolveOptVirtualEntrySymbolName();
132        } else if (MiscUtils.isVirtualCall(mi, call)) {
133            resolveSymbolName = binaryContainer.getResolveVirtualEntrySymbolName();
134        } else {
135            throw new InternalError("Unknown call type in " + mi.asTag() + " @ " + call.pcOffset + " for call" + call.target);
136        }
137        return resolveSymbolName;
138    }
139
140}
141