1 /* 2 * Copyright (c) 2016, 2020, 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 24 25 26 package jdk.tools.jaotc; 27 28 import jdk.tools.jaotc.binformat.BinaryContainer; 29 import jdk.tools.jaotc.binformat.Symbol; 30 31 import jdk.vm.ci.code.site.Call; 32 33 final class ForeignGotCallSiteRelocationSymbol extends CallSiteRelocationSymbol { 34 ForeignGotCallSiteRelocationSymbol(CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation, DataBuilder dataBuilder)35 ForeignGotCallSiteRelocationSymbol(CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation, DataBuilder dataBuilder) { 36 super(createPltSymbol(dataBuilder, mi, call, callSiteRelocation)); 37 } 38 createPltSymbol(DataBuilder dataBuilder, CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation)39 private static Symbol createPltSymbol(DataBuilder dataBuilder, CompiledMethodInfo mi, Call call, CallSiteRelocationInfo callSiteRelocation) { 40 BinaryContainer binaryContainer = dataBuilder.getBinaryContainer(); 41 String vmSymbolName = callSiteRelocation.targetSymbol; 42 43 // Add relocation to GOT cell for call resolution jump. 44 String pltSymbolName = "plt." + vmSymbolName; 45 Symbol pltSymbol = binaryContainer.getSymbol(pltSymbolName); 46 47 if (pltSymbol == null) { 48 String gotSymbolName = "got." + vmSymbolName; 49 Symbol gotSymbol = binaryContainer.getGotSymbol(gotSymbolName); 50 assert gotSymbol != null : "undefined VM got symbol '" + gotSymbolName + "' for call at " + call.pcOffset + " in " + mi.getMethodInfo().getSymbolName(); 51 52 // Generate PLT jump (do it only once). 53 final int pltStartOffset = binaryContainer.getCodeContainer().getByteStreamSize(); 54 final int pltEndOffset = pltStartOffset + addPltJump(dataBuilder); 55 56 // Link GOT cell to PLT jump. 57 pltSymbol = createCodeContainerSymbol(binaryContainer, pltSymbolName, pltStartOffset); 58 addExternalPltToGotRelocation(binaryContainer, gotSymbol, pltEndOffset); 59 } 60 61 return pltSymbol; 62 } 63 addPltJump(DataBuilder dataBuilder)64 private static int addPltJump(DataBuilder dataBuilder) { 65 ELFMacroAssembler masm = ELFMacroAssembler.getELFMacroAssembler(dataBuilder.getBackend().getTarget(), dataBuilder.getBackend().getRuntime().getOptions()); 66 byte[] code = masm.getPLTJumpCode(); // It includes alignment nops. 67 int size = masm.currentEndOfInstruction(); 68 dataBuilder.getBinaryContainer().appendCodeBytes(code, 0, code.length); 69 return size; 70 } 71 72 } 73