lib/Object/ELFObjectFile.cpp

   1 //===- ELFObjectFile.cpp - ELF object file implementation -----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Part of the ELFObjectFile class implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Object/ELFObjectFile.h"
  15 #include "llvm/ADT/Triple.h"
  16 #include "llvm/BinaryFormat/ELF.h"
  17 #include "llvm/MC/SubtargetFeature.h"
  18 #include "llvm/Object/ELF.h"
  19 #include "llvm/Object/ELFTypes.h"
  20 #include "llvm/Object/Error.h"
  21 #include "llvm/Support/ARMAttributeParser.h"
  22 #include "llvm/Support/ARMBuildAttributes.h"
  23 #include "llvm/Support/Endian.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include <algorithm>
  27 #include <cstddef>
  28 #include <cstdint>
  29 #include <memory>
  30 #include <string>
  31 #include <system_error>
  32 #include <utility>
  33
  34 using namespace llvm;
  35 using namespace object;
  36
  37 ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source)
  38     : ObjectFile(Type, Source) {}
  39
  40 ErrorOr<std::unique_ptr<ObjectFile>>
  41 ObjectFile::createELFObjectFile(MemoryBufferRef Obj) {
  42   std::pair<unsigned char, unsigned char> Ident =
  43       getElfArchType(Obj.getBuffer());
  44   std::size_t MaxAlignment =
  45       1ULL << countTrailingZeros(uintptr_t(Obj.getBufferStart()));
  46
  47   if (MaxAlignment < 2)
  48     return object_error::parse_failed;
  49
  50   std::error_code EC;
  51   std::unique_ptr<ObjectFile> R;
  52   if (Ident.first == ELF::ELFCLASS32) {
  53     if (Ident.second == ELF::ELFDATA2LSB)
  54       R.reset(new ELFObjectFile<ELFType<support::little, false>>(Obj, EC));
  55     else if (Ident.second == ELF::ELFDATA2MSB)
  56       R.reset(new ELFObjectFile<ELFType<support::big, false>>(Obj, EC));
  57     else
  58       return object_error::parse_failed;
  59   } else if (Ident.first == ELF::ELFCLASS64) {
  60     if (Ident.second == ELF::ELFDATA2LSB)
  61       R.reset(new ELFObjectFile<ELFType<support::little, true>>(Obj, EC));
  62     else if (Ident.second == ELF::ELFDATA2MSB)
  63       R.reset(new ELFObjectFile<ELFType<support::big, true>>(Obj, EC));
  64     else
  65       return object_error::parse_failed;
  66   } else {
  67     return object_error::parse_failed;
  68   }
  69
  70   if (EC)
  71     return EC;
  72   return std::move(R);
  73 }
  74
  75 SubtargetFeatures ELFObjectFileBase::getMIPSFeatures() const {
  76   SubtargetFeatures Features;
  77   unsigned PlatformFlags;
  78   getPlatformFlags(PlatformFlags);
  79
  80   switch (PlatformFlags & ELF::EF_MIPS_ARCH) {
  81   case ELF::EF_MIPS_ARCH_1:
  82     break;
  83   case ELF::EF_MIPS_ARCH_2:
  84     Features.AddFeature("mips2");
  85     break;
  86   case ELF::EF_MIPS_ARCH_3:
  87     Features.AddFeature("mips3");
  88     break;
  89   case ELF::EF_MIPS_ARCH_4:
  90     Features.AddFeature("mips4");
  91     break;
  92   case ELF::EF_MIPS_ARCH_5:
  93     Features.AddFeature("mips5");
  94     break;
  95   case ELF::EF_MIPS_ARCH_32:
  96     Features.AddFeature("mips32");
  97     break;
  98   case ELF::EF_MIPS_ARCH_64:
  99     Features.AddFeature("mips64");
 100     break;
 101   case ELF::EF_MIPS_ARCH_32R2:
 102     Features.AddFeature("mips32r2");
 103     break;
 104   case ELF::EF_MIPS_ARCH_64R2:
 105     Features.AddFeature("mips64r2");
 106     break;
 107   case ELF::EF_MIPS_ARCH_32R6:
 108     Features.AddFeature("mips32r6");
 109     break;
 110   case ELF::EF_MIPS_ARCH_64R6:
 111     Features.AddFeature("mips64r6");
 112     break;
 113   default:
 114     llvm_unreachable("Unknown EF_MIPS_ARCH value");
 115   }
 116
 117   switch (PlatformFlags & ELF::EF_MIPS_MACH) {
 118   case ELF::EF_MIPS_MACH_NONE:
 119     // No feature associated with this value.
 120     break;
 121   case ELF::EF_MIPS_MACH_OCTEON:
 122     Features.AddFeature("cnmips");
 123     break;
 124   default:
 125     llvm_unreachable("Unknown EF_MIPS_ARCH value");
 126   }
 127
 128   if (PlatformFlags & ELF::EF_MIPS_ARCH_ASE_M16)
 129     Features.AddFeature("mips16");
 130   if (PlatformFlags & ELF::EF_MIPS_MICROMIPS)
 131     Features.AddFeature("micromips");
 132
 133   return Features;
 134 }
 135
 136 SubtargetFeatures ELFObjectFileBase::getARMFeatures() const {
 137   SubtargetFeatures Features;
 138   ARMAttributeParser Attributes;
 139   std::error_code EC = getBuildAttributes(Attributes);
 140   if (EC)
 141     return SubtargetFeatures();
 142
 143   // both ARMv7-M and R have to support thumb hardware div
 144   bool isV7 = false;
 145   if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch))
 146     isV7 = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch)
 147       == ARMBuildAttrs::v7;
 148
 149   if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch_profile)) {
 150     switch(Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile)) {
 151     case ARMBuildAttrs::ApplicationProfile:
 152       Features.AddFeature("aclass");
 153       break;
 154     case ARMBuildAttrs::RealTimeProfile:
 155       Features.AddFeature("rclass");
 156       if (isV7)
 157         Features.AddFeature("hwdiv");
 158       break;
 159     case ARMBuildAttrs::MicroControllerProfile:
 160       Features.AddFeature("mclass");
 161       if (isV7)
 162         Features.AddFeature("hwdiv");
 163       break;
 164     }
 165   }
 166
 167   if (Attributes.hasAttribute(ARMBuildAttrs::THUMB_ISA_use)) {
 168     switch(Attributes.getAttributeValue(ARMBuildAttrs::THUMB_ISA_use)) {
 169     default:
 170       break;
 171     case ARMBuildAttrs::Not_Allowed:
 172       Features.AddFeature("thumb", false);
 173       Features.AddFeature("thumb2", false);
 174       break;
 175     case ARMBuildAttrs::AllowThumb32:
 176       Features.AddFeature("thumb2");
 177       break;
 178     }
 179   }
 180
 181   if (Attributes.hasAttribute(ARMBuildAttrs::FP_arch)) {
 182     switch(Attributes.getAttributeValue(ARMBuildAttrs::FP_arch)) {
 183     default:
 184       break;
 185     case ARMBuildAttrs::Not_Allowed:
 186       Features.AddFeature("vfp2", false);
 187       Features.AddFeature("vfp3", false);
 188       Features.AddFeature("vfp4", false);
 189       break;
 190     case ARMBuildAttrs::AllowFPv2:
 191       Features.AddFeature("vfp2");
 192       break;
 193     case ARMBuildAttrs::AllowFPv3A:
 194     case ARMBuildAttrs::AllowFPv3B:
 195       Features.AddFeature("vfp3");
 196       break;
 197     case ARMBuildAttrs::AllowFPv4A:
 198     case ARMBuildAttrs::AllowFPv4B:
 199       Features.AddFeature("vfp4");
 200       break;
 201     }
 202   }
 203
 204   if (Attributes.hasAttribute(ARMBuildAttrs::Advanced_SIMD_arch)) {
 205     switch(Attributes.getAttributeValue(ARMBuildAttrs::Advanced_SIMD_arch)) {
 206     default:
 207       break;
 208     case ARMBuildAttrs::Not_Allowed:
 209       Features.AddFeature("neon", false);
 210       Features.AddFeature("fp16", false);
 211       break;
 212     case ARMBuildAttrs::AllowNeon:
 213       Features.AddFeature("neon");
 214       break;
 215     case ARMBuildAttrs::AllowNeon2:
 216       Features.AddFeature("neon");
 217       Features.AddFeature("fp16");
 218       break;
 219     }
 220   }
 221
 222   if (Attributes.hasAttribute(ARMBuildAttrs::DIV_use)) {
 223     switch(Attributes.getAttributeValue(ARMBuildAttrs::DIV_use)) {
 224     default:
 225       break;
 226     case ARMBuildAttrs::DisallowDIV:
 227       Features.AddFeature("hwdiv", false);
 228       Features.AddFeature("hwdiv-arm", false);
 229       break;
 230     case ARMBuildAttrs::AllowDIVExt:
 231       Features.AddFeature("hwdiv");
 232       Features.AddFeature("hwdiv-arm");
 233       break;
 234     }
 235   }
 236
 237   return Features;
 238 }
 239
 240 SubtargetFeatures ELFObjectFileBase::getFeatures() const {
 241   switch (getEMachine()) {
 242   case ELF::EM_MIPS:
 243     return getMIPSFeatures();
 244   case ELF::EM_ARM:
 245     return getARMFeatures();
 246   default:
 247     return SubtargetFeatures();
 248   }
 249 }
 250
 251 // FIXME Encode from a tablegen description or target parser.
 252 void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const {
 253   if (TheTriple.getSubArch() != Triple::NoSubArch)
 254     return;
 255
 256   ARMAttributeParser Attributes;
 257   std::error_code EC = getBuildAttributes(Attributes);
 258   if (EC)
 259     return;
 260
 261   std::string Triple;
 262   // Default to ARM, but use the triple if it's been set.
 263   if (TheTriple.isThumb())
 264     Triple = "thumb";
 265   else
 266     Triple = "arm";
 267
 268   if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch)) {
 269     switch(Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch)) {
 270     case ARMBuildAttrs::v4:
 271       Triple += "v4";
 272       break;
 273     case ARMBuildAttrs::v4T:
 274       Triple += "v4t";
 275       break;
 276     case ARMBuildAttrs::v5T:
 277       Triple += "v5t";
 278       break;
 279     case ARMBuildAttrs::v5TE:
 280       Triple += "v5te";
 281       break;
 282     case ARMBuildAttrs::v5TEJ:
 283       Triple += "v5tej";
 284       break;
 285     case ARMBuildAttrs::v6:
 286       Triple += "v6";
 287       break;
 288     case ARMBuildAttrs::v6KZ:
 289       Triple += "v6kz";
 290       break;
 291     case ARMBuildAttrs::v6T2:
 292       Triple += "v6t2";
 293       break;
 294     case ARMBuildAttrs::v6K:
 295       Triple += "v6k";
 296       break;
 297     case ARMBuildAttrs::v7:
 298       Triple += "v7";
 299       break;
 300     case ARMBuildAttrs::v6_M:
 301       Triple += "v6m";
 302       break;
 303     case ARMBuildAttrs::v6S_M:
 304       Triple += "v6sm";
 305       break;
 306     case ARMBuildAttrs::v7E_M:
 307       Triple += "v7em";
 308       break;
 309     }
 310   }
 311   if (!isLittleEndian())
 312     Triple += "eb";
 313
 314   TheTriple.setArchName(Triple);
 315 }