1 //===--- RuntimeDyldCOFFThumb.h --- COFF/Thumb 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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // COFF thumb support for MC-JIT runtime dynamic linker. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFTHUMB_H 14 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFTHUMB_H 15 16 #include "../RuntimeDyldCOFF.h" 17 #include "llvm/BinaryFormat/COFF.h" 18 #include "llvm/Object/COFF.h" 19 20 #define DEBUG_TYPE "dyld" 21 22 namespace llvm { 23 24 static bool isThumbFunc(object::symbol_iterator Symbol, 25 const object::ObjectFile &Obj, 26 object::section_iterator Section) { 27 Expected<object::SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 28 if (!SymTypeOrErr) { 29 std::string Buf; 30 raw_string_ostream OS(Buf); 31 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS); 32 OS.flush(); 33 report_fatal_error(Buf); 34 } 35 36 if (*SymTypeOrErr != object::SymbolRef::ST_Function) 37 return false; 38 39 // We check the IMAGE_SCN_MEM_16BIT flag in the section of the symbol to tell 40 // if it's thumb or not 41 return cast<object::COFFObjectFile>(Obj) 42 .getCOFFSection(*Section) 43 ->Characteristics & 44 COFF::IMAGE_SCN_MEM_16BIT; 45 } 46 47 class RuntimeDyldCOFFThumb : public RuntimeDyldCOFF { 48 public: 49 RuntimeDyldCOFFThumb(RuntimeDyld::MemoryManager &MM, 50 JITSymbolResolver &Resolver) 51 : RuntimeDyldCOFF(MM, Resolver) {} 52 53 unsigned getMaxStubSize() const override { 54 return 16; // 8-byte load instructions, 4-byte jump, 4-byte padding 55 } 56 57 unsigned getStubAlignment() override { return 1; } 58 59 Expected<object::relocation_iterator> 60 processRelocationRef(unsigned SectionID, 61 object::relocation_iterator RelI, 62 const object::ObjectFile &Obj, 63 ObjSectionToIDMap &ObjSectionToID, 64 StubMap &Stubs) override { 65 auto Symbol = RelI->getSymbol(); 66 if (Symbol == Obj.symbol_end()) 67 report_fatal_error("Unknown symbol in relocation"); 68 69 Expected<StringRef> TargetNameOrErr = Symbol->getName(); 70 if (!TargetNameOrErr) 71 return TargetNameOrErr.takeError(); 72 StringRef TargetName = *TargetNameOrErr; 73 74 auto SectionOrErr = Symbol->getSection(); 75 if (!SectionOrErr) 76 return SectionOrErr.takeError(); 77 auto Section = *SectionOrErr; 78 79 uint64_t RelType = RelI->getType(); 80 uint64_t Offset = RelI->getOffset(); 81 82 // Determine the Addend used to adjust the relocation value. 83 uint64_t Addend = 0; 84 SectionEntry &AddendSection = Sections[SectionID]; 85 uintptr_t ObjTarget = AddendSection.getObjAddress() + Offset; 86 uint8_t *Displacement = (uint8_t *)ObjTarget; 87 88 switch (RelType) { 89 case COFF::IMAGE_REL_ARM_ADDR32: 90 case COFF::IMAGE_REL_ARM_ADDR32NB: 91 case COFF::IMAGE_REL_ARM_SECREL: 92 Addend = readBytesUnaligned(Displacement, 4); 93 break; 94 default: 95 break; 96 } 97 98 #if !defined(NDEBUG) 99 SmallString<32> RelTypeName; 100 RelI->getTypeName(RelTypeName); 101 #endif 102 LLVM_DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset 103 << " RelType: " << RelTypeName << " TargetName: " 104 << TargetName << " Addend " << Addend << "\n"); 105 106 unsigned TargetSectionID = -1; 107 if (Section == Obj.section_end()) { 108 RelocationEntry RE(SectionID, Offset, RelType, 0, -1, 0, 0, 0, false, 0); 109 addRelocationForSymbol(RE, TargetName); 110 } else { 111 if (auto TargetSectionIDOrErr = 112 findOrEmitSection(Obj, *Section, Section->isText(), ObjSectionToID)) 113 TargetSectionID = *TargetSectionIDOrErr; 114 else 115 return TargetSectionIDOrErr.takeError(); 116 117 // We need to find out if the relocation is relative to a thumb function 118 // so that we include the ISA selection bit when resolve the relocation 119 bool IsTargetThumbFunc = isThumbFunc(Symbol, Obj, Section); 120 121 switch (RelType) { 122 default: llvm_unreachable("unsupported relocation type"); 123 case COFF::IMAGE_REL_ARM_ABSOLUTE: 124 // This relocation is ignored. 125 break; 126 case COFF::IMAGE_REL_ARM_ADDR32: { 127 RelocationEntry RE = RelocationEntry( 128 SectionID, Offset, RelType, Addend, TargetSectionID, 129 getSymbolOffset(*Symbol), 0, 0, false, 0, IsTargetThumbFunc); 130 addRelocationForSection(RE, TargetSectionID); 131 break; 132 } 133 case COFF::IMAGE_REL_ARM_ADDR32NB: { 134 RelocationEntry RE = 135 RelocationEntry(SectionID, Offset, RelType, Addend, TargetSectionID, 136 getSymbolOffset(*Symbol), 0, 0, false, 0); 137 addRelocationForSection(RE, TargetSectionID); 138 break; 139 } 140 case COFF::IMAGE_REL_ARM_SECTION: { 141 RelocationEntry RE = 142 RelocationEntry(TargetSectionID, Offset, RelType, 0); 143 addRelocationForSection(RE, TargetSectionID); 144 break; 145 } 146 case COFF::IMAGE_REL_ARM_SECREL: { 147 RelocationEntry RE = RelocationEntry(SectionID, Offset, RelType, 148 getSymbolOffset(*Symbol) + Addend); 149 addRelocationForSection(RE, TargetSectionID); 150 break; 151 } 152 case COFF::IMAGE_REL_ARM_MOV32T: { 153 RelocationEntry RE = RelocationEntry( 154 SectionID, Offset, RelType, Addend, TargetSectionID, 155 getSymbolOffset(*Symbol), 0, 0, false, 0, IsTargetThumbFunc); 156 addRelocationForSection(RE, TargetSectionID); 157 break; 158 } 159 case COFF::IMAGE_REL_ARM_BRANCH20T: 160 case COFF::IMAGE_REL_ARM_BRANCH24T: 161 case COFF::IMAGE_REL_ARM_BLX23T: { 162 RelocationEntry RE = 163 RelocationEntry(SectionID, Offset, RelType, 164 getSymbolOffset(*Symbol) + Addend, true, 0); 165 addRelocationForSection(RE, TargetSectionID); 166 break; 167 } 168 } 169 } 170 171 return ++RelI; 172 } 173 174 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override { 175 const auto Section = Sections[RE.SectionID]; 176 uint8_t *Target = Section.getAddressWithOffset(RE.Offset); 177 int ISASelectionBit = RE.IsTargetThumbFunc ? 1 : 0; 178 179 switch (RE.RelType) { 180 default: llvm_unreachable("unsupported relocation type"); 181 case COFF::IMAGE_REL_ARM_ABSOLUTE: 182 // This relocation is ignored. 183 break; 184 case COFF::IMAGE_REL_ARM_ADDR32: { 185 // The target's 32-bit VA. 186 uint64_t Result = 187 RE.Sections.SectionA == static_cast<uint32_t>(-1) 188 ? Value 189 : Sections[RE.Sections.SectionA].getLoadAddressWithOffset(RE.Addend); 190 Result |= ISASelectionBit; 191 assert(Result <= UINT32_MAX && "relocation overflow"); 192 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 193 << " RelType: IMAGE_REL_ARM_ADDR32" 194 << " TargetSection: " << RE.Sections.SectionA 195 << " Value: " << format("0x%08" PRIx32, Result) 196 << '\n'); 197 writeBytesUnaligned(Result, Target, 4); 198 break; 199 } 200 case COFF::IMAGE_REL_ARM_ADDR32NB: { 201 // The target's 32-bit RVA. 202 // NOTE: use Section[0].getLoadAddress() as an approximation of ImageBase 203 uint64_t Result = Sections[RE.Sections.SectionA].getLoadAddress() - 204 Sections[0].getLoadAddress() + RE.Addend; 205 assert(Result <= UINT32_MAX && "relocation overflow"); 206 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 207 << " RelType: IMAGE_REL_ARM_ADDR32NB" 208 << " TargetSection: " << RE.Sections.SectionA 209 << " Value: " << format("0x%08" PRIx32, Result) 210 << '\n'); 211 Result |= ISASelectionBit; 212 writeBytesUnaligned(Result, Target, 4); 213 break; 214 } 215 case COFF::IMAGE_REL_ARM_SECTION: 216 // 16-bit section index of the section that contains the target. 217 assert(static_cast<uint32_t>(RE.SectionID) <= UINT16_MAX && 218 "relocation overflow"); 219 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 220 << " RelType: IMAGE_REL_ARM_SECTION Value: " 221 << RE.SectionID << '\n'); 222 writeBytesUnaligned(RE.SectionID, Target, 2); 223 break; 224 case COFF::IMAGE_REL_ARM_SECREL: 225 // 32-bit offset of the target from the beginning of its section. 226 assert(static_cast<uint64_t>(RE.Addend) <= UINT32_MAX && 227 "relocation overflow"); 228 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 229 << " RelType: IMAGE_REL_ARM_SECREL Value: " << RE.Addend 230 << '\n'); 231 writeBytesUnaligned(RE.Addend, Target, 2); 232 break; 233 case COFF::IMAGE_REL_ARM_MOV32T: { 234 // 32-bit VA of the target applied to a contiguous MOVW+MOVT pair. 235 uint64_t Result = 236 Sections[RE.Sections.SectionA].getLoadAddressWithOffset(RE.Addend); 237 assert(Result <= UINT32_MAX && "relocation overflow"); 238 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 239 << " RelType: IMAGE_REL_ARM_MOV32T" 240 << " TargetSection: " << RE.Sections.SectionA 241 << " Value: " << format("0x%08" PRIx32, Result) 242 << '\n'); 243 244 // MOVW(T3): |11110|i|10|0|1|0|0|imm4|0|imm3|Rd|imm8| 245 // imm32 = zext imm4:i:imm3:imm8 246 // MOVT(T1): |11110|i|10|1|1|0|0|imm4|0|imm3|Rd|imm8| 247 // imm16 = imm4:i:imm3:imm8 248 249 auto EncodeImmediate = [](uint8_t *Bytes, uint16_t Immediate) { 250 Bytes[0] |= ((Immediate & 0xf000) >> 12); 251 Bytes[1] |= ((Immediate & 0x0800) >> 11); 252 Bytes[2] |= ((Immediate & 0x00ff) >> 0); 253 Bytes[3] |= (((Immediate & 0x0700) >> 8) << 4); 254 }; 255 256 EncodeImmediate(&Target[0], 257 (static_cast<uint32_t>(Result) >> 00) | ISASelectionBit); 258 EncodeImmediate(&Target[4], static_cast<uint32_t>(Result) >> 16); 259 260 break; 261 } 262 case COFF::IMAGE_REL_ARM_BRANCH20T: { 263 // The most significant 20-bits of the signed 21-bit relative displacement 264 uint64_t Value = 265 RE.Addend - (Sections[RE.SectionID].getLoadAddress() + RE.Offset) - 4; 266 assert(static_cast<int64_t>(RE.Addend) <= INT32_MAX && 267 "relocation overflow"); 268 assert(static_cast<int64_t>(RE.Addend) >= INT32_MIN && 269 "relocation underflow"); 270 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 271 << " RelType: IMAGE_REL_ARM_BRANCH20T" 272 << " Value: " << static_cast<int32_t>(Value) << '\n'); 273 static_cast<void>(Value); 274 llvm_unreachable("unimplemented relocation"); 275 break; 276 } 277 case COFF::IMAGE_REL_ARM_BRANCH24T: { 278 // The most significant 24-bits of the signed 25-bit relative displacement 279 uint64_t Value = 280 RE.Addend - (Sections[RE.SectionID].getLoadAddress() + RE.Offset) - 4; 281 assert(static_cast<int64_t>(RE.Addend) <= INT32_MAX && 282 "relocation overflow"); 283 assert(static_cast<int64_t>(RE.Addend) >= INT32_MIN && 284 "relocation underflow"); 285 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 286 << " RelType: IMAGE_REL_ARM_BRANCH24T" 287 << " Value: " << static_cast<int32_t>(Value) << '\n'); 288 static_cast<void>(Value); 289 llvm_unreachable("unimplemented relocation"); 290 break; 291 } 292 case COFF::IMAGE_REL_ARM_BLX23T: { 293 // The most significant 24-bits of the signed 25-bit relative displacement 294 uint64_t Value = 295 RE.Addend - (Sections[RE.SectionID].getLoadAddress() + RE.Offset) - 4; 296 assert(static_cast<int64_t>(RE.Addend) <= INT32_MAX && 297 "relocation overflow"); 298 assert(static_cast<int64_t>(RE.Addend) >= INT32_MIN && 299 "relocation underflow"); 300 LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset 301 << " RelType: IMAGE_REL_ARM_BLX23T" 302 << " Value: " << static_cast<int32_t>(Value) << '\n'); 303 static_cast<void>(Value); 304 llvm_unreachable("unimplemented relocation"); 305 break; 306 } 307 } 308 } 309 310 void registerEHFrames() override {} 311 }; 312 313 } 314 315 #endif 316