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1//===--- RuntimeDyldCOFFI386.h --- COFF/X86_64 specific code ---*- C++ --*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// COFF x86 support for MC-JIT runtime dynamic linker.10//11//===----------------------------------------------------------------------===//12 13#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFI386_H14#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFI386_H15 16#include "../RuntimeDyldCOFF.h"17#include "llvm/BinaryFormat/COFF.h"18#include "llvm/Object/COFF.h"19 20#define DEBUG_TYPE "dyld"21 22namespace llvm {23 24class RuntimeDyldCOFFI386 : public RuntimeDyldCOFF {25public:26 RuntimeDyldCOFFI386(RuntimeDyld::MemoryManager &MM,27 JITSymbolResolver &Resolver)28 : RuntimeDyldCOFF(MM, Resolver, 4, COFF::IMAGE_REL_I386_DIR32) {}29 30 unsigned getMaxStubSize() const override {31 return 8; // 2-byte jmp instruction + 32-bit relative address + 2 byte pad32 }33 34 Align getStubAlignment() override { return Align(1); }35 36 Expected<object::relocation_iterator>37 processRelocationRef(unsigned SectionID,38 object::relocation_iterator RelI,39 const object::ObjectFile &Obj,40 ObjSectionToIDMap &ObjSectionToID,41 StubMap &Stubs) override {42 43 auto Symbol = RelI->getSymbol();44 if (Symbol == Obj.symbol_end())45 report_fatal_error("Unknown symbol in relocation");46 47 Expected<StringRef> TargetNameOrErr = Symbol->getName();48 if (!TargetNameOrErr)49 return TargetNameOrErr.takeError();50 StringRef TargetName = *TargetNameOrErr;51 52 auto SectionOrErr = Symbol->getSection();53 if (!SectionOrErr)54 return SectionOrErr.takeError();55 auto Section = *SectionOrErr;56 bool IsExtern = Section == Obj.section_end();57 58 uint64_t RelType = RelI->getType();59 uint64_t Offset = RelI->getOffset();60 61 unsigned TargetSectionID = -1;62 uint64_t TargetOffset = -1;63 if (TargetName.starts_with(getImportSymbolPrefix())) {64 TargetSectionID = SectionID;65 TargetOffset = getDLLImportOffset(SectionID, Stubs, TargetName, true);66 TargetName = StringRef();67 IsExtern = false;68 } else if (!IsExtern) {69 if (auto TargetSectionIDOrErr = findOrEmitSection(70 Obj, *Section, Section->isText(), ObjSectionToID))71 TargetSectionID = *TargetSectionIDOrErr;72 else73 return TargetSectionIDOrErr.takeError();74 if (RelType != COFF::IMAGE_REL_I386_SECTION)75 TargetOffset = getSymbolOffset(*Symbol);76 }77 78 // Determine the Addend used to adjust the relocation value.79 uint64_t Addend = 0;80 SectionEntry &AddendSection = Sections[SectionID];81 uintptr_t ObjTarget = AddendSection.getObjAddress() + Offset;82 uint8_t *Displacement = (uint8_t *)ObjTarget;83 84 switch (RelType) {85 case COFF::IMAGE_REL_I386_DIR32:86 case COFF::IMAGE_REL_I386_DIR32NB:87 case COFF::IMAGE_REL_I386_SECREL:88 case COFF::IMAGE_REL_I386_REL32: {89 Addend = readBytesUnaligned(Displacement, 4);90 break;91 }92 default:93 break;94 }95 96#if !defined(NDEBUG)97 SmallString<32> RelTypeName;98 RelI->getTypeName(RelTypeName);99#endif100 LLVM_DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset101 << " RelType: " << RelTypeName << " TargetName: "102 << TargetName << " Addend " << Addend << "\n");103 104 if (IsExtern) {105 RelocationEntry RE(SectionID, Offset, RelType, 0, -1, 0, 0, 0, false, 0);106 addRelocationForSymbol(RE, TargetName);107 } else {108 109 switch (RelType) {110 case COFF::IMAGE_REL_I386_ABSOLUTE:111 // This relocation is ignored.112 break;113 case COFF::IMAGE_REL_I386_DIR32:114 case COFF::IMAGE_REL_I386_DIR32NB:115 case COFF::IMAGE_REL_I386_REL32: {116 RelocationEntry RE =117 RelocationEntry(SectionID, Offset, RelType, Addend, TargetSectionID,118 TargetOffset, 0, 0, false, 0);119 addRelocationForSection(RE, TargetSectionID);120 break;121 }122 case COFF::IMAGE_REL_I386_SECTION: {123 RelocationEntry RE =124 RelocationEntry(TargetSectionID, Offset, RelType, 0);125 addRelocationForSection(RE, TargetSectionID);126 break;127 }128 case COFF::IMAGE_REL_I386_SECREL: {129 RelocationEntry RE =130 RelocationEntry(SectionID, Offset, RelType, TargetOffset + Addend);131 addRelocationForSection(RE, TargetSectionID);132 break;133 }134 default:135 llvm_unreachable("unsupported relocation type");136 }137 }138 139 return ++RelI;140 }141 142 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {143 const auto Section = Sections[RE.SectionID];144 uint8_t *Target = Section.getAddressWithOffset(RE.Offset);145 146 switch (RE.RelType) {147 case COFF::IMAGE_REL_I386_ABSOLUTE:148 // This relocation is ignored.149 break;150 case COFF::IMAGE_REL_I386_DIR32: {151 // The target's 32-bit VA.152 uint64_t Result =153 RE.Sections.SectionA == static_cast<uint32_t>(-1)154 ? Value155 : Sections[RE.Sections.SectionA].getLoadAddressWithOffset(156 RE.Addend);157 assert(Result <= UINT32_MAX && "relocation overflow");158 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset159 << " RelType: IMAGE_REL_I386_DIR32"160 << " TargetSection: " << RE.Sections.SectionA161 << " Value: " << format("0x%08" PRIx32, Result)162 << '\n');163 writeBytesUnaligned(Result, Target, 4);164 break;165 }166 case COFF::IMAGE_REL_I386_DIR32NB: {167 // The target's 32-bit RVA.168 // NOTE: use Section[0].getLoadAddress() as an approximation of ImageBase169 uint64_t Result =170 Sections[RE.Sections.SectionA].getLoadAddressWithOffset(RE.Addend) -171 Sections[0].getLoadAddress();172 assert(Result <= UINT32_MAX && "relocation overflow");173 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset174 << " RelType: IMAGE_REL_I386_DIR32NB"175 << " TargetSection: " << RE.Sections.SectionA176 << " Value: " << format("0x%08" PRIx32, Result)177 << '\n');178 writeBytesUnaligned(Result, Target, 4);179 break;180 }181 case COFF::IMAGE_REL_I386_REL32: {182 // 32-bit relative displacement to the target.183 uint64_t Result = RE.Sections.SectionA == static_cast<uint32_t>(-1)184 ? Value185 : Sections[RE.Sections.SectionA].getLoadAddress();186 Result = Result - Section.getLoadAddress() + RE.Addend - 4 - RE.Offset;187 assert(static_cast<int64_t>(Result) <= INT32_MAX &&188 "relocation overflow");189 assert(static_cast<int64_t>(Result) >= INT32_MIN &&190 "relocation underflow");191 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset192 << " RelType: IMAGE_REL_I386_REL32"193 << " TargetSection: " << RE.Sections.SectionA194 << " Value: " << format("0x%08" PRIx32, Result)195 << '\n');196 writeBytesUnaligned(Result, Target, 4);197 break;198 }199 case COFF::IMAGE_REL_I386_SECTION:200 // 16-bit section index of the section that contains the target.201 assert(static_cast<uint32_t>(RE.SectionID) <= UINT16_MAX &&202 "relocation overflow");203 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset204 << " RelType: IMAGE_REL_I386_SECTION Value: "205 << RE.SectionID << '\n');206 writeBytesUnaligned(RE.SectionID, Target, 2);207 break;208 case COFF::IMAGE_REL_I386_SECREL:209 // 32-bit offset of the target from the beginning of its section.210 assert(static_cast<uint64_t>(RE.Addend) <= UINT32_MAX &&211 "relocation overflow");212 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset213 << " RelType: IMAGE_REL_I386_SECREL Value: "214 << RE.Addend << '\n');215 writeBytesUnaligned(RE.Addend, Target, 4);216 break;217 default:218 llvm_unreachable("unsupported relocation type");219 }220 }221 222 void registerEHFrames() override {}223};224 225}226 227#endif228 229