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; 28 29import jdk.vm.ci.code.site.Call; 30 31final class ForeignGotCallSiteRelocationSymbol extends CallSiteRelocationSymbol { 32 33 public ForeignGotCallSiteRelocationSymbol(CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation, DataBuilder dataBuilder) { 34 super(createPltSymbol(dataBuilder, mi, call, callSiteRelocation)); 35 } 36 37 private static Symbol createPltSymbol(DataBuilder dataBuilder, CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation) { 38 BinaryContainer binaryContainer = dataBuilder.getBinaryContainer(); 39 String vmSymbolName = callSiteRelocation.targetSymbol; 40 41 // Add relocation to GOT cell for call resolution jump. 42 String pltSymbolName = "plt." + vmSymbolName; 43 Symbol pltSymbol = binaryContainer.getSymbol(pltSymbolName); 44 45 if (pltSymbol == null) { 46 String gotSymbolName = "got." + vmSymbolName; 47 Symbol gotSymbol = binaryContainer.getGotSymbol(gotSymbolName); 48 assert gotSymbol != null : "undefined VM got symbol '" + gotSymbolName + "' for call at " + call.pcOffset + " in " + mi.getMethodInfo().getSymbolName(); 49 50 // Generate PLT jump (do it only once). 51 final int pltStartOffset = binaryContainer.getCodeContainer().getByteStreamSize(); 52 final int pltEndOffset = pltStartOffset + addPltJump(dataBuilder); 53 54 // Link GOT cell to PLT jump. 55 pltSymbol = createCodeContainerSymbol(binaryContainer, pltSymbolName, pltStartOffset); 56 addExternalPltToGotRelocation(binaryContainer, gotSymbol, pltEndOffset); 57 } 58 59 return pltSymbol; 60 } 61 62 private static int addPltJump(DataBuilder dataBuilder) { 63 ELFMacroAssembler masm = ELFMacroAssembler.getELFMacroAssembler(dataBuilder.getBackend().getTarget()); 64 byte[] code = masm.getPLTJumpCode(); // It includes alignment nops. 65 int size = masm.currentEndOfInstruction(); 66 dataBuilder.getBinaryContainer().appendCodeBytes(code, 0, code.length); 67 return size; 68 } 69 70} 71