llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp

   1 //===-- PPCELFObjectWriter.cpp - PPC ELF Writer ---------------------------===//
   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 #include "MCTargetDesc/PPCFixupKinds.h"
  10 #include "MCTargetDesc/PPCMCExpr.h"
  11 #include "MCTargetDesc/PPCMCTargetDesc.h"
  12 #include "llvm/MC/MCELFObjectWriter.h"
  13 #include "llvm/MC/MCExpr.h"
  14 #include "llvm/MC/MCObjectWriter.h"
  15 #include "llvm/MC/MCSymbolELF.h"
  16 #include "llvm/MC/MCValue.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18
  19 using namespace llvm;
  20
  21 namespace {
  22   class PPCELFObjectWriter : public MCELFObjectTargetWriter {
  23   public:
  24     PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI);
  25
  26   protected:
  27     unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
  28                           const MCFixup &Fixup, bool IsPCRel) const override;
  29
  30     bool needsRelocateWithSymbol(const MCValue &Val, const MCSymbol &Sym,
  31                                  unsigned Type) const override;
  32   };
  33 }
  34
  35 PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI)
  36   : MCELFObjectTargetWriter(Is64Bit, OSABI,
  37                             Is64Bit ?  ELF::EM_PPC64 : ELF::EM_PPC,
  38                             /*HasRelocationAddend*/ true) {}
  39
  40 static MCSymbolRefExpr::VariantKind getAccessVariant(const MCValue &Target,
  41                                                      const MCFixup &Fixup) {
  42   const MCExpr *Expr = Fixup.getValue();
  43
  44   if (Expr->getKind() != MCExpr::Target)
  45     return Target.getAccessVariant();
  46
  47   switch (cast<PPCMCExpr>(Expr)->getKind()) {
  48   case PPCMCExpr::VK_PPC_None:
  49     return MCSymbolRefExpr::VK_None;
  50   case PPCMCExpr::VK_PPC_LO:
  51     return MCSymbolRefExpr::VK_PPC_LO;
  52   case PPCMCExpr::VK_PPC_HI:
  53     return MCSymbolRefExpr::VK_PPC_HI;
  54   case PPCMCExpr::VK_PPC_HA:
  55     return MCSymbolRefExpr::VK_PPC_HA;
  56   case PPCMCExpr::VK_PPC_HIGH:
  57     return MCSymbolRefExpr::VK_PPC_HIGH;
  58   case PPCMCExpr::VK_PPC_HIGHA:
  59     return MCSymbolRefExpr::VK_PPC_HIGHA;
  60   case PPCMCExpr::VK_PPC_HIGHERA:
  61     return MCSymbolRefExpr::VK_PPC_HIGHERA;
  62   case PPCMCExpr::VK_PPC_HIGHER:
  63     return MCSymbolRefExpr::VK_PPC_HIGHER;
  64   case PPCMCExpr::VK_PPC_HIGHEST:
  65     return MCSymbolRefExpr::VK_PPC_HIGHEST;
  66   case PPCMCExpr::VK_PPC_HIGHESTA:
  67     return MCSymbolRefExpr::VK_PPC_HIGHESTA;
  68   }
  69   llvm_unreachable("unknown PPCMCExpr kind");
  70 }
  71
  72 unsigned PPCELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
  73                                           const MCFixup &Fixup,
  74                                           bool IsPCRel) const {
  75   MCFixupKind Kind = Fixup.getKind();
  76   if (Kind >= FirstLiteralRelocationKind)
  77     return Kind - FirstLiteralRelocationKind;
  78   MCSymbolRefExpr::VariantKind Modifier = getAccessVariant(Target, Fixup);
  79
  80   // determine the type of the relocation
  81   unsigned Type;
  82   if (IsPCRel) {
  83     switch (Fixup.getTargetKind()) {
  84     default:
  85       llvm_unreachable("Unimplemented");
  86     case PPC::fixup_ppc_br24:
  87     case PPC::fixup_ppc_br24abs:
  88     case PPC::fixup_ppc_br24_notoc:
  89       switch (Modifier) {
  90       default: llvm_unreachable("Unsupported Modifier");
  91       case MCSymbolRefExpr::VK_None:
  92         Type = ELF::R_PPC_REL24;
  93         break;
  94       case MCSymbolRefExpr::VK_PLT:
  95         Type = ELF::R_PPC_PLTREL24;
  96         break;
  97       case MCSymbolRefExpr::VK_PPC_LOCAL:
  98         Type = ELF::R_PPC_LOCAL24PC;
  99         break;
 100       case MCSymbolRefExpr::VK_PPC_NOTOC:
 101         Type = ELF::R_PPC64_REL24_NOTOC;
 102         break;
 103       }
 104       break;
 105     case PPC::fixup_ppc_brcond14:
 106     case PPC::fixup_ppc_brcond14abs:
 107       Type = ELF::R_PPC_REL14;
 108       break;
 109     case PPC::fixup_ppc_half16:
 110       switch (Modifier) {
 111       default: llvm_unreachable("Unsupported Modifier");
 112       case MCSymbolRefExpr::VK_None:
 113         Type = ELF::R_PPC_REL16;
 114         break;
 115       case MCSymbolRefExpr::VK_PPC_LO:
 116         Type = ELF::R_PPC_REL16_LO;
 117         break;
 118       case MCSymbolRefExpr::VK_PPC_HI:
 119         Type = ELF::R_PPC_REL16_HI;
 120         break;
 121       case MCSymbolRefExpr::VK_PPC_HA:
 122         Type = ELF::R_PPC_REL16_HA;
 123         break;
 124       }
 125       break;
 126     case PPC::fixup_ppc_half16ds:
 127     case PPC::fixup_ppc_half16dq:
 128       Target.print(errs());
 129       errs() << '\n';
 130       report_fatal_error("Invalid PC-relative half16ds relocation");
 131     case PPC::fixup_ppc_pcrel34:
 132       switch (Modifier) {
 133       default:
 134         llvm_unreachable("Unsupported Modifier for fixup_ppc_pcrel34");
 135       case MCSymbolRefExpr::VK_PCREL:
 136         Type = ELF::R_PPC64_PCREL34;
 137         break;
 138       case MCSymbolRefExpr::VK_PPC_GOT_PCREL:
 139         Type = ELF::R_PPC64_GOT_PCREL34;
 140         break;
 141       case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL:
 142         Type = ELF::R_PPC64_GOT_TLSGD_PCREL34;
 143         break;
 144       case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL:
 145         Type = ELF::R_PPC64_GOT_TLSLD_PCREL34;
 146         break;
 147       case MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL:
 148         Type = ELF::R_PPC64_GOT_TPREL_PCREL34;
 149         break;
 150       }
 151       break;
 152     case FK_Data_4:
 153     case FK_PCRel_4:
 154       Type = ELF::R_PPC_REL32;
 155       break;
 156     case FK_Data_8:
 157     case FK_PCRel_8:
 158       Type = ELF::R_PPC64_REL64;
 159       break;
 160     }
 161   } else {
 162     switch (Fixup.getTargetKind()) {
 163       default: llvm_unreachable("invalid fixup kind!");
 164     case PPC::fixup_ppc_br24abs:
 165       Type = ELF::R_PPC_ADDR24;
 166       break;
 167     case PPC::fixup_ppc_brcond14abs:
 168       Type = ELF::R_PPC_ADDR14; // XXX: or BRNTAKEN?_
 169       break;
 170     case PPC::fixup_ppc_half16:
 171       switch (Modifier) {
 172       default: llvm_unreachable("Unsupported Modifier");
 173       case MCSymbolRefExpr::VK_None:
 174         Type = ELF::R_PPC_ADDR16;
 175         break;
 176       case MCSymbolRefExpr::VK_PPC_LO:
 177         Type = ELF::R_PPC_ADDR16_LO;
 178         break;
 179       case MCSymbolRefExpr::VK_PPC_HI:
 180         Type = ELF::R_PPC_ADDR16_HI;
 181         break;
 182       case MCSymbolRefExpr::VK_PPC_HA:
 183         Type = ELF::R_PPC_ADDR16_HA;
 184         break;
 185       case MCSymbolRefExpr::VK_PPC_HIGH:
 186         Type = ELF::R_PPC64_ADDR16_HIGH;
 187         break;
 188       case MCSymbolRefExpr::VK_PPC_HIGHA:
 189         Type = ELF::R_PPC64_ADDR16_HIGHA;
 190         break;
 191       case MCSymbolRefExpr::VK_PPC_HIGHER:
 192         Type = ELF::R_PPC64_ADDR16_HIGHER;
 193         break;
 194       case MCSymbolRefExpr::VK_PPC_HIGHERA:
 195         Type = ELF::R_PPC64_ADDR16_HIGHERA;
 196         break;
 197       case MCSymbolRefExpr::VK_PPC_HIGHEST:
 198         Type = ELF::R_PPC64_ADDR16_HIGHEST;
 199         break;
 200       case MCSymbolRefExpr::VK_PPC_HIGHESTA:
 201         Type = ELF::R_PPC64_ADDR16_HIGHESTA;
 202         break;
 203       case MCSymbolRefExpr::VK_GOT:
 204         Type = ELF::R_PPC_GOT16;
 205         break;
 206       case MCSymbolRefExpr::VK_PPC_GOT_LO:
 207         Type = ELF::R_PPC_GOT16_LO;
 208         break;
 209       case MCSymbolRefExpr::VK_PPC_GOT_HI:
 210         Type = ELF::R_PPC_GOT16_HI;
 211         break;
 212       case MCSymbolRefExpr::VK_PPC_GOT_HA:
 213         Type = ELF::R_PPC_GOT16_HA;
 214         break;
 215       case MCSymbolRefExpr::VK_PPC_TOC:
 216         Type = ELF::R_PPC64_TOC16;
 217         break;
 218       case MCSymbolRefExpr::VK_PPC_TOC_LO:
 219         Type = ELF::R_PPC64_TOC16_LO;
 220         break;
 221       case MCSymbolRefExpr::VK_PPC_TOC_HI:
 222         Type = ELF::R_PPC64_TOC16_HI;
 223         break;
 224       case MCSymbolRefExpr::VK_PPC_TOC_HA:
 225         Type = ELF::R_PPC64_TOC16_HA;
 226         break;
 227       case MCSymbolRefExpr::VK_TPREL:
 228         Type = ELF::R_PPC_TPREL16;
 229         break;
 230       case MCSymbolRefExpr::VK_PPC_TPREL_LO:
 231         Type = ELF::R_PPC_TPREL16_LO;
 232         break;
 233       case MCSymbolRefExpr::VK_PPC_TPREL_HI:
 234         Type = ELF::R_PPC_TPREL16_HI;
 235         break;
 236       case MCSymbolRefExpr::VK_PPC_TPREL_HA:
 237         Type = ELF::R_PPC_TPREL16_HA;
 238         break;
 239       case MCSymbolRefExpr::VK_PPC_TPREL_HIGH:
 240         Type = ELF::R_PPC64_TPREL16_HIGH;
 241         break;
 242       case MCSymbolRefExpr::VK_PPC_TPREL_HIGHA:
 243         Type = ELF::R_PPC64_TPREL16_HIGHA;
 244         break;
 245       case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
 246         Type = ELF::R_PPC64_TPREL16_HIGHER;
 247         break;
 248       case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
 249         Type = ELF::R_PPC64_TPREL16_HIGHERA;
 250         break;
 251       case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
 252         Type = ELF::R_PPC64_TPREL16_HIGHEST;
 253         break;
 254       case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
 255         Type = ELF::R_PPC64_TPREL16_HIGHESTA;
 256         break;
 257       case MCSymbolRefExpr::VK_DTPREL:
 258         Type = ELF::R_PPC64_DTPREL16;
 259         break;
 260       case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
 261         Type = ELF::R_PPC64_DTPREL16_LO;
 262         break;
 263       case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
 264         Type = ELF::R_PPC64_DTPREL16_HI;
 265         break;
 266       case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
 267         Type = ELF::R_PPC64_DTPREL16_HA;
 268         break;
 269       case MCSymbolRefExpr::VK_PPC_DTPREL_HIGH:
 270         Type = ELF::R_PPC64_DTPREL16_HIGH;
 271         break;
 272       case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHA:
 273         Type = ELF::R_PPC64_DTPREL16_HIGHA;
 274         break;
 275       case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
 276         Type = ELF::R_PPC64_DTPREL16_HIGHER;
 277         break;
 278       case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
 279         Type = ELF::R_PPC64_DTPREL16_HIGHERA;
 280         break;
 281       case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
 282         Type = ELF::R_PPC64_DTPREL16_HIGHEST;
 283         break;
 284       case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
 285         Type = ELF::R_PPC64_DTPREL16_HIGHESTA;
 286         break;
 287       case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
 288         if (is64Bit())
 289           Type = ELF::R_PPC64_GOT_TLSGD16;
 290         else
 291           Type = ELF::R_PPC_GOT_TLSGD16;
 292         break;
 293       case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
 294         Type = ELF::R_PPC64_GOT_TLSGD16_LO;
 295         break;
 296       case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
 297         Type = ELF::R_PPC64_GOT_TLSGD16_HI;
 298         break;
 299       case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
 300         Type = ELF::R_PPC64_GOT_TLSGD16_HA;
 301         break;
 302       case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
 303         if (is64Bit())
 304           Type = ELF::R_PPC64_GOT_TLSLD16;
 305         else
 306           Type = ELF::R_PPC_GOT_TLSLD16;
 307         break;
 308       case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
 309         Type = ELF::R_PPC64_GOT_TLSLD16_LO;
 310         break;
 311       case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
 312         Type = ELF::R_PPC64_GOT_TLSLD16_HI;
 313         break;
 314       case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
 315         Type = ELF::R_PPC64_GOT_TLSLD16_HA;
 316         break;
 317       case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
 318         /* We don't have R_PPC64_GOT_TPREL16, but since GOT offsets
 319            are always 4-aligned, we can use R_PPC64_GOT_TPREL16_DS.  */
 320         Type = ELF::R_PPC64_GOT_TPREL16_DS;
 321         break;
 322       case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
 323         /* We don't have R_PPC64_GOT_TPREL16_LO, but since GOT offsets
 324            are always 4-aligned, we can use R_PPC64_GOT_TPREL16_LO_DS.  */
 325         Type = ELF::R_PPC64_GOT_TPREL16_LO_DS;
 326         break;
 327       case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
 328         Type = ELF::R_PPC64_GOT_TPREL16_HI;
 329         break;
 330       case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
 331         /* We don't have R_PPC64_GOT_DTPREL16, but since GOT offsets
 332            are always 4-aligned, we can use R_PPC64_GOT_DTPREL16_DS.  */
 333         Type = ELF::R_PPC64_GOT_DTPREL16_DS;
 334         break;
 335       case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
 336         /* We don't have R_PPC64_GOT_DTPREL16_LO, but since GOT offsets
 337            are always 4-aligned, we can use R_PPC64_GOT_DTPREL16_LO_DS.  */
 338         Type = ELF::R_PPC64_GOT_DTPREL16_LO_DS;
 339         break;
 340       case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
 341         Type = ELF::R_PPC64_GOT_TPREL16_HA;
 342         break;
 343       case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
 344         Type = ELF::R_PPC64_GOT_DTPREL16_HI;
 345         break;
 346       case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
 347         Type = ELF::R_PPC64_GOT_DTPREL16_HA;
 348         break;
 349       }
 350       break;
 351     case PPC::fixup_ppc_half16ds:
 352     case PPC::fixup_ppc_half16dq:
 353       switch (Modifier) {
 354       default: llvm_unreachable("Unsupported Modifier");
 355       case MCSymbolRefExpr::VK_None:
 356         Type = ELF::R_PPC64_ADDR16_DS;
 357         break;
 358       case MCSymbolRefExpr::VK_PPC_LO:
 359         Type = ELF::R_PPC64_ADDR16_LO_DS;
 360         break;
 361       case MCSymbolRefExpr::VK_GOT:
 362         Type = ELF::R_PPC64_GOT16_DS;
 363         break;
 364       case MCSymbolRefExpr::VK_PPC_GOT_LO:
 365         Type = ELF::R_PPC64_GOT16_LO_DS;
 366         break;
 367       case MCSymbolRefExpr::VK_PPC_TOC:
 368         Type = ELF::R_PPC64_TOC16_DS;
 369         break;
 370       case MCSymbolRefExpr::VK_PPC_TOC_LO:
 371         Type = ELF::R_PPC64_TOC16_LO_DS;
 372         break;
 373       case MCSymbolRefExpr::VK_TPREL:
 374         Type = ELF::R_PPC64_TPREL16_DS;
 375         break;
 376       case MCSymbolRefExpr::VK_PPC_TPREL_LO:
 377         Type = ELF::R_PPC64_TPREL16_LO_DS;
 378         break;
 379       case MCSymbolRefExpr::VK_DTPREL:
 380         Type = ELF::R_PPC64_DTPREL16_DS;
 381         break;
 382       case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
 383         Type = ELF::R_PPC64_DTPREL16_LO_DS;
 384         break;
 385       case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
 386         Type = ELF::R_PPC64_GOT_TPREL16_DS;
 387         break;
 388       case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
 389         Type = ELF::R_PPC64_GOT_TPREL16_LO_DS;
 390         break;
 391       case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
 392         Type = ELF::R_PPC64_GOT_DTPREL16_DS;
 393         break;
 394       case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
 395         Type = ELF::R_PPC64_GOT_DTPREL16_LO_DS;
 396         break;
 397       }
 398       break;
 399     case PPC::fixup_ppc_nofixup:
 400       switch (Modifier) {
 401       default: llvm_unreachable("Unsupported Modifier");
 402       case MCSymbolRefExpr::VK_PPC_TLSGD:
 403         if (is64Bit())
 404           Type = ELF::R_PPC64_TLSGD;
 405         else
 406           Type = ELF::R_PPC_TLSGD;
 407         break;
 408       case MCSymbolRefExpr::VK_PPC_TLSLD:
 409         if (is64Bit())
 410           Type = ELF::R_PPC64_TLSLD;
 411         else
 412           Type = ELF::R_PPC_TLSLD;
 413         break;
 414       case MCSymbolRefExpr::VK_PPC_TLS:
 415         if (is64Bit())
 416           Type = ELF::R_PPC64_TLS;
 417         else
 418           Type = ELF::R_PPC_TLS;
 419         break;
 420       case MCSymbolRefExpr::VK_PPC_TLS_PCREL:
 421         Type = ELF::R_PPC64_TLS;
 422         break;
 423       }
 424       break;
 425     case PPC::fixup_ppc_imm34:
 426       switch (Modifier) {
 427       default:
 428         report_fatal_error("Unsupported Modifier for fixup_ppc_imm34.");
 429       case MCSymbolRefExpr::VK_DTPREL:
 430         Type = ELF::R_PPC64_DTPREL34;
 431         break;
 432       case MCSymbolRefExpr::VK_TPREL:
 433         Type = ELF::R_PPC64_TPREL34;
 434         break;
 435       }
 436       break;
 437     case FK_Data_8:
 438       switch (Modifier) {
 439       default: llvm_unreachable("Unsupported Modifier");
 440       case MCSymbolRefExpr::VK_PPC_TOCBASE:
 441         Type = ELF::R_PPC64_TOC;
 442         break;
 443       case MCSymbolRefExpr::VK_None:
 444         Type = ELF::R_PPC64_ADDR64;
 445         break;
 446       case MCSymbolRefExpr::VK_PPC_DTPMOD:
 447         Type = ELF::R_PPC64_DTPMOD64;
 448         break;
 449       case MCSymbolRefExpr::VK_TPREL:
 450         Type = ELF::R_PPC64_TPREL64;
 451         break;
 452       case MCSymbolRefExpr::VK_DTPREL:
 453         Type = ELF::R_PPC64_DTPREL64;
 454         break;
 455       }
 456       break;
 457     case FK_Data_4:
 458       switch (Modifier) {
 459       case MCSymbolRefExpr::VK_DTPREL:
 460         Type = ELF::R_PPC_DTPREL32;
 461         break;
 462       default:
 463         Type = ELF::R_PPC_ADDR32;
 464       }
 465       break;
 466     case FK_Data_2:
 467       Type = ELF::R_PPC_ADDR16;
 468       break;
 469     }
 470   }
 471   return Type;
 472 }
 473
 474 bool PPCELFObjectWriter::needsRelocateWithSymbol(const MCValue &,
 475                                                  const MCSymbol &Sym,
 476                                                  unsigned Type) const {
 477   switch (Type) {
 478     default:
 479       return false;
 480
 481     case ELF::R_PPC_REL24:
 482     case ELF::R_PPC64_REL24_NOTOC:
 483       // If the target symbol has a local entry point, we must keep the
 484       // target symbol to preserve that information for the linker.
 485       // The "other" values are stored in the last 6 bits of the second byte.
 486       // The traditional defines for STO values assume the full byte and thus
 487       // the shift to pack it.
 488       unsigned Other = cast<MCSymbolELF>(Sym).getOther() << 2;
 489       return (Other & ELF::STO_PPC64_LOCAL_MASK) != 0;
 490   }
 491 }
 492
 493 std::unique_ptr<MCObjectTargetWriter>
 494 llvm::createPPCELFObjectWriter(bool Is64Bit, uint8_t OSABI) {
 495   return std::make_unique<PPCELFObjectWriter>(Is64Bit, OSABI);
 496 }