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      1 //===-- HexagonAsmBackend.cpp - Hexagon Assembler Backend -----------------===//
      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 #include "Hexagon.h"
     11 #include "HexagonFixupKinds.h"
     12 #include "MCTargetDesc/HexagonBaseInfo.h"
     13 #include "MCTargetDesc/HexagonMCChecker.h"
     14 #include "MCTargetDesc/HexagonMCCodeEmitter.h"
     15 #include "MCTargetDesc/HexagonMCInstrInfo.h"
     16 #include "MCTargetDesc/HexagonMCShuffler.h"
     17 #include "MCTargetDesc/HexagonMCTargetDesc.h"
     18 #include "llvm/MC/MCAsmBackend.h"
     19 #include "llvm/MC/MCAsmLayout.h"
     20 #include "llvm/MC/MCAssembler.h"
     21 #include "llvm/MC/MCContext.h"
     22 #include "llvm/MC/MCELFObjectWriter.h"
     23 #include "llvm/MC/MCFixupKindInfo.h"
     24 #include "llvm/MC/MCInstrInfo.h"
     25 #include "llvm/MC/MCObjectWriter.h"
     26 #include "llvm/Support/Debug.h"
     27 #include "llvm/Support/TargetRegistry.h"
     28 
     29 #include <sstream>
     30 
     31 using namespace llvm;
     32 using namespace Hexagon;
     33 
     34 #define DEBUG_TYPE "hexagon-asm-backend"
     35 
     36 static cl::opt<bool> DisableFixup
     37   ("mno-fixup", cl::desc("Disable fixing up resolved relocations for Hexagon"));
     38 
     39 namespace {
     40 
     41 class HexagonAsmBackend : public MCAsmBackend {
     42   uint8_t OSABI;
     43   StringRef CPU;
     44   mutable uint64_t relaxedCnt;
     45   std::unique_ptr <MCInstrInfo> MCII;
     46   std::unique_ptr <MCInst *> RelaxTarget;
     47   MCInst * Extender;
     48 
     49   void ReplaceInstruction(MCCodeEmitter &E, MCRelaxableFragment &RF,
     50                           MCInst &HMB) const {
     51     SmallVector<MCFixup, 4> Fixups;
     52     SmallString<256> Code;
     53     raw_svector_ostream VecOS(Code);
     54     E.encodeInstruction(HMB, VecOS, Fixups, *RF.getSubtargetInfo());
     55 
     56     // Update the fragment.
     57     RF.setInst(HMB);
     58     RF.getContents() = Code;
     59     RF.getFixups() = Fixups;
     60   }
     61 
     62 public:
     63   HexagonAsmBackend(const Target &T, const Triple &TT, uint8_t OSABI,
     64                     StringRef CPU)
     65       : MCAsmBackend(support::little), OSABI(OSABI), CPU(CPU),
     66         MCII(T.createMCInstrInfo()), RelaxTarget(new MCInst *),
     67         Extender(nullptr) {}
     68 
     69   std::unique_ptr<MCObjectTargetWriter>
     70   createObjectTargetWriter() const override {
     71     return createHexagonELFObjectWriter(OSABI, CPU);
     72   }
     73 
     74   void setExtender(MCContext &Context) const {
     75     if (Extender == nullptr)
     76       const_cast<HexagonAsmBackend *>(this)->Extender = new (Context) MCInst;
     77   }
     78 
     79   MCInst *takeExtender() const {
     80     assert(Extender != nullptr);
     81     MCInst * Result = Extender;
     82     const_cast<HexagonAsmBackend *>(this)->Extender = nullptr;
     83     return Result;
     84   }
     85 
     86   unsigned getNumFixupKinds() const override {
     87     return Hexagon::NumTargetFixupKinds;
     88   }
     89 
     90   const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override {
     91     const static MCFixupKindInfo Infos[Hexagon::NumTargetFixupKinds] = {
     92       // This table *must* be in same the order of fixup_* kinds in
     93       // HexagonFixupKinds.h.
     94       //
     95       // namei                          offset  bits    flags
     96       { "fixup_Hexagon_B22_PCREL",      0,      32,     MCFixupKindInfo::FKF_IsPCRel },
     97       { "fixup_Hexagon_B15_PCREL",      0,      32,     MCFixupKindInfo::FKF_IsPCRel },
     98       { "fixup_Hexagon_B7_PCREL",       0,      32,     MCFixupKindInfo::FKF_IsPCRel },
     99       { "fixup_Hexagon_LO16",           0,      32,     0 },
    100       { "fixup_Hexagon_HI16",           0,      32,     0 },
    101       { "fixup_Hexagon_32",             0,      32,     0 },
    102       { "fixup_Hexagon_16",             0,      32,     0 },
    103       { "fixup_Hexagon_8",              0,      32,     0 },
    104       { "fixup_Hexagon_GPREL16_0",      0,      32,     0 },
    105       { "fixup_Hexagon_GPREL16_1",      0,      32,     0 },
    106       { "fixup_Hexagon_GPREL16_2",      0,      32,     0 },
    107       { "fixup_Hexagon_GPREL16_3",      0,      32,     0 },
    108       { "fixup_Hexagon_HL16",           0,      32,     0 },
    109       { "fixup_Hexagon_B13_PCREL",      0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    110       { "fixup_Hexagon_B9_PCREL",       0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    111       { "fixup_Hexagon_B32_PCREL_X",    0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    112       { "fixup_Hexagon_32_6_X",         0,      32,     0 },
    113       { "fixup_Hexagon_B22_PCREL_X",    0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    114       { "fixup_Hexagon_B15_PCREL_X",    0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    115       { "fixup_Hexagon_B13_PCREL_X",    0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    116       { "fixup_Hexagon_B9_PCREL_X",     0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    117       { "fixup_Hexagon_B7_PCREL_X",     0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    118       { "fixup_Hexagon_16_X",           0,      32,     0 },
    119       { "fixup_Hexagon_12_X",           0,      32,     0 },
    120       { "fixup_Hexagon_11_X",           0,      32,     0 },
    121       { "fixup_Hexagon_10_X",           0,      32,     0 },
    122       { "fixup_Hexagon_9_X",            0,      32,     0 },
    123       { "fixup_Hexagon_8_X",            0,      32,     0 },
    124       { "fixup_Hexagon_7_X",            0,      32,     0 },
    125       { "fixup_Hexagon_6_X",            0,      32,     0 },
    126       { "fixup_Hexagon_32_PCREL",       0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    127       { "fixup_Hexagon_COPY",           0,      32,     0 },
    128       { "fixup_Hexagon_GLOB_DAT",       0,      32,     0 },
    129       { "fixup_Hexagon_JMP_SLOT",       0,      32,     0 },
    130       { "fixup_Hexagon_RELATIVE",       0,      32,     0 },
    131       { "fixup_Hexagon_PLT_B22_PCREL",  0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    132       { "fixup_Hexagon_GOTREL_LO16",    0,      32,     0 },
    133       { "fixup_Hexagon_GOTREL_HI16",    0,      32,     0 },
    134       { "fixup_Hexagon_GOTREL_32",      0,      32,     0 },
    135       { "fixup_Hexagon_GOT_LO16",       0,      32,     0 },
    136       { "fixup_Hexagon_GOT_HI16",       0,      32,     0 },
    137       { "fixup_Hexagon_GOT_32",         0,      32,     0 },
    138       { "fixup_Hexagon_GOT_16",         0,      32,     0 },
    139       { "fixup_Hexagon_DTPMOD_32",      0,      32,     0 },
    140       { "fixup_Hexagon_DTPREL_LO16",    0,      32,     0 },
    141       { "fixup_Hexagon_DTPREL_HI16",    0,      32,     0 },
    142       { "fixup_Hexagon_DTPREL_32",      0,      32,     0 },
    143       { "fixup_Hexagon_DTPREL_16",      0,      32,     0 },
    144       { "fixup_Hexagon_GD_PLT_B22_PCREL",0,     32,     MCFixupKindInfo::FKF_IsPCRel },
    145       { "fixup_Hexagon_LD_PLT_B22_PCREL",0,     32,     MCFixupKindInfo::FKF_IsPCRel },
    146       { "fixup_Hexagon_GD_GOT_LO16",    0,      32,     0 },
    147       { "fixup_Hexagon_GD_GOT_HI16",    0,      32,     0 },
    148       { "fixup_Hexagon_GD_GOT_32",      0,      32,     0 },
    149       { "fixup_Hexagon_GD_GOT_16",      0,      32,     0 },
    150       { "fixup_Hexagon_LD_GOT_LO16",    0,      32,     0 },
    151       { "fixup_Hexagon_LD_GOT_HI16",    0,      32,     0 },
    152       { "fixup_Hexagon_LD_GOT_32",      0,      32,     0 },
    153       { "fixup_Hexagon_LD_GOT_16",      0,      32,     0 },
    154       { "fixup_Hexagon_IE_LO16",        0,      32,     0 },
    155       { "fixup_Hexagon_IE_HI16",        0,      32,     0 },
    156       { "fixup_Hexagon_IE_32",          0,      32,     0 },
    157       { "fixup_Hexagon_IE_16",          0,      32,     0 },
    158       { "fixup_Hexagon_IE_GOT_LO16",    0,      32,     0 },
    159       { "fixup_Hexagon_IE_GOT_HI16",    0,      32,     0 },
    160       { "fixup_Hexagon_IE_GOT_32",      0,      32,     0 },
    161       { "fixup_Hexagon_IE_GOT_16",      0,      32,     0 },
    162       { "fixup_Hexagon_TPREL_LO16",     0,      32,     0 },
    163       { "fixup_Hexagon_TPREL_HI16",     0,      32,     0 },
    164       { "fixup_Hexagon_TPREL_32",       0,      32,     0 },
    165       { "fixup_Hexagon_TPREL_16",       0,      32,     0 },
    166       { "fixup_Hexagon_6_PCREL_X",      0,      32,     MCFixupKindInfo::FKF_IsPCRel },
    167       { "fixup_Hexagon_GOTREL_32_6_X",  0,      32,     0 },
    168       { "fixup_Hexagon_GOTREL_16_X",    0,      32,     0 },
    169       { "fixup_Hexagon_GOTREL_11_X",    0,      32,     0 },
    170       { "fixup_Hexagon_GOT_32_6_X",     0,      32,     0 },
    171       { "fixup_Hexagon_GOT_16_X",       0,      32,     0 },
    172       { "fixup_Hexagon_GOT_11_X",       0,      32,     0 },
    173       { "fixup_Hexagon_DTPREL_32_6_X",  0,      32,     0 },
    174       { "fixup_Hexagon_DTPREL_16_X",    0,      32,     0 },
    175       { "fixup_Hexagon_DTPREL_11_X",    0,      32,     0 },
    176       { "fixup_Hexagon_GD_GOT_32_6_X",  0,      32,     0 },
    177       { "fixup_Hexagon_GD_GOT_16_X",    0,      32,     0 },
    178       { "fixup_Hexagon_GD_GOT_11_X",    0,      32,     0 },
    179       { "fixup_Hexagon_LD_GOT_32_6_X",  0,      32,     0 },
    180       { "fixup_Hexagon_LD_GOT_16_X",    0,      32,     0 },
    181       { "fixup_Hexagon_LD_GOT_11_X",    0,      32,     0 },
    182       { "fixup_Hexagon_IE_32_6_X",      0,      32,     0 },
    183       { "fixup_Hexagon_IE_16_X",        0,      32,     0 },
    184       { "fixup_Hexagon_IE_GOT_32_6_X",  0,      32,     0 },
    185       { "fixup_Hexagon_IE_GOT_16_X",    0,      32,     0 },
    186       { "fixup_Hexagon_IE_GOT_11_X",    0,      32,     0 },
    187       { "fixup_Hexagon_TPREL_32_6_X",   0,      32,     0 },
    188       { "fixup_Hexagon_TPREL_16_X",     0,      32,     0 },
    189       { "fixup_Hexagon_TPREL_11_X",     0,      32,     0 },
    190       { "fixup_Hexagon_GD_PLT_B22_PCREL_X",0,     32,     MCFixupKindInfo::FKF_IsPCRel },
    191       { "fixup_Hexagon_GD_PLT_B32_PCREL_X",0,     32,     MCFixupKindInfo::FKF_IsPCRel },
    192       { "fixup_Hexagon_LD_PLT_B22_PCREL_X",0,     32,     MCFixupKindInfo::FKF_IsPCRel },
    193       { "fixup_Hexagon_LD_PLT_B32_PCREL_X",0,     32,     MCFixupKindInfo::FKF_IsPCRel }
    194     };
    195 
    196     if (Kind < FirstTargetFixupKind)
    197       return MCAsmBackend::getFixupKindInfo(Kind);
    198 
    199     assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
    200            "Invalid kind!");
    201     return Infos[Kind - FirstTargetFixupKind];
    202   }
    203 
    204   bool shouldForceRelocation(const MCAssembler &Asm, const MCFixup &Fixup,
    205                              const MCValue &Target) override {
    206     MCFixupKind Kind = Fixup.getKind();
    207 
    208     switch((unsigned)Kind) {
    209       default:
    210         llvm_unreachable("Unknown Fixup Kind!");
    211 
    212       case fixup_Hexagon_LO16:
    213       case fixup_Hexagon_HI16:
    214       case fixup_Hexagon_16:
    215       case fixup_Hexagon_8:
    216       case fixup_Hexagon_GPREL16_0:
    217       case fixup_Hexagon_GPREL16_1:
    218       case fixup_Hexagon_GPREL16_2:
    219       case fixup_Hexagon_GPREL16_3:
    220       case fixup_Hexagon_HL16:
    221       case fixup_Hexagon_32_6_X:
    222       case fixup_Hexagon_16_X:
    223       case fixup_Hexagon_12_X:
    224       case fixup_Hexagon_11_X:
    225       case fixup_Hexagon_10_X:
    226       case fixup_Hexagon_9_X:
    227       case fixup_Hexagon_8_X:
    228       case fixup_Hexagon_7_X:
    229       case fixup_Hexagon_6_X:
    230       case fixup_Hexagon_COPY:
    231       case fixup_Hexagon_GLOB_DAT:
    232       case fixup_Hexagon_JMP_SLOT:
    233       case fixup_Hexagon_RELATIVE:
    234       case fixup_Hexagon_PLT_B22_PCREL:
    235       case fixup_Hexagon_GOTREL_LO16:
    236       case fixup_Hexagon_GOTREL_HI16:
    237       case fixup_Hexagon_GOTREL_32:
    238       case fixup_Hexagon_GOT_LO16:
    239       case fixup_Hexagon_GOT_HI16:
    240       case fixup_Hexagon_GOT_32:
    241       case fixup_Hexagon_GOT_16:
    242       case fixup_Hexagon_DTPMOD_32:
    243       case fixup_Hexagon_DTPREL_LO16:
    244       case fixup_Hexagon_DTPREL_HI16:
    245       case fixup_Hexagon_DTPREL_32:
    246       case fixup_Hexagon_DTPREL_16:
    247       case fixup_Hexagon_GD_PLT_B22_PCREL:
    248       case fixup_Hexagon_LD_PLT_B22_PCREL:
    249       case fixup_Hexagon_GD_GOT_LO16:
    250       case fixup_Hexagon_GD_GOT_HI16:
    251       case fixup_Hexagon_GD_GOT_32:
    252       case fixup_Hexagon_GD_GOT_16:
    253       case fixup_Hexagon_LD_GOT_LO16:
    254       case fixup_Hexagon_LD_GOT_HI16:
    255       case fixup_Hexagon_LD_GOT_32:
    256       case fixup_Hexagon_LD_GOT_16:
    257       case fixup_Hexagon_IE_LO16:
    258       case fixup_Hexagon_IE_HI16:
    259       case fixup_Hexagon_IE_32:
    260       case fixup_Hexagon_IE_16:
    261       case fixup_Hexagon_IE_GOT_LO16:
    262       case fixup_Hexagon_IE_GOT_HI16:
    263       case fixup_Hexagon_IE_GOT_32:
    264       case fixup_Hexagon_IE_GOT_16:
    265       case fixup_Hexagon_TPREL_LO16:
    266       case fixup_Hexagon_TPREL_HI16:
    267       case fixup_Hexagon_TPREL_32:
    268       case fixup_Hexagon_TPREL_16:
    269       case fixup_Hexagon_GOTREL_32_6_X:
    270       case fixup_Hexagon_GOTREL_16_X:
    271       case fixup_Hexagon_GOTREL_11_X:
    272       case fixup_Hexagon_GOT_32_6_X:
    273       case fixup_Hexagon_GOT_16_X:
    274       case fixup_Hexagon_GOT_11_X:
    275       case fixup_Hexagon_DTPREL_32_6_X:
    276       case fixup_Hexagon_DTPREL_16_X:
    277       case fixup_Hexagon_DTPREL_11_X:
    278       case fixup_Hexagon_GD_GOT_32_6_X:
    279       case fixup_Hexagon_GD_GOT_16_X:
    280       case fixup_Hexagon_GD_GOT_11_X:
    281       case fixup_Hexagon_LD_GOT_32_6_X:
    282       case fixup_Hexagon_LD_GOT_16_X:
    283       case fixup_Hexagon_LD_GOT_11_X:
    284       case fixup_Hexagon_IE_32_6_X:
    285       case fixup_Hexagon_IE_16_X:
    286       case fixup_Hexagon_IE_GOT_32_6_X:
    287       case fixup_Hexagon_IE_GOT_16_X:
    288       case fixup_Hexagon_IE_GOT_11_X:
    289       case fixup_Hexagon_TPREL_32_6_X:
    290       case fixup_Hexagon_TPREL_16_X:
    291       case fixup_Hexagon_TPREL_11_X:
    292       case fixup_Hexagon_32_PCREL:
    293       case fixup_Hexagon_6_PCREL_X:
    294       case fixup_Hexagon_23_REG:
    295       case fixup_Hexagon_27_REG:
    296       case fixup_Hexagon_GD_PLT_B22_PCREL_X:
    297       case fixup_Hexagon_GD_PLT_B32_PCREL_X:
    298       case fixup_Hexagon_LD_PLT_B22_PCREL_X:
    299       case fixup_Hexagon_LD_PLT_B32_PCREL_X:
    300         // These relocations should always have a relocation recorded
    301         return true;
    302 
    303       case fixup_Hexagon_B22_PCREL:
    304         //IsResolved = false;
    305         break;
    306 
    307       case fixup_Hexagon_B13_PCREL:
    308       case fixup_Hexagon_B13_PCREL_X:
    309       case fixup_Hexagon_B32_PCREL_X:
    310       case fixup_Hexagon_B22_PCREL_X:
    311       case fixup_Hexagon_B15_PCREL:
    312       case fixup_Hexagon_B15_PCREL_X:
    313       case fixup_Hexagon_B9_PCREL:
    314       case fixup_Hexagon_B9_PCREL_X:
    315       case fixup_Hexagon_B7_PCREL:
    316       case fixup_Hexagon_B7_PCREL_X:
    317         if (DisableFixup)
    318           return true;
    319         break;
    320 
    321       case FK_Data_1:
    322       case FK_Data_2:
    323       case FK_Data_4:
    324       case FK_PCRel_4:
    325       case fixup_Hexagon_32:
    326         // Leave these relocations alone as they are used for EH.
    327         return false;
    328     }
    329     return false;
    330   }
    331 
    332   /// getFixupKindNumBytes - The number of bytes the fixup may change.
    333   static unsigned getFixupKindNumBytes(unsigned Kind) {
    334     switch (Kind) {
    335     default:
    336         return 0;
    337 
    338       case FK_Data_1:
    339         return 1;
    340       case FK_Data_2:
    341         return 2;
    342       case FK_Data_4:         // this later gets mapped to R_HEX_32
    343       case FK_PCRel_4:        // this later gets mapped to R_HEX_32_PCREL
    344       case fixup_Hexagon_32:
    345       case fixup_Hexagon_B32_PCREL_X:
    346       case fixup_Hexagon_B22_PCREL:
    347       case fixup_Hexagon_B22_PCREL_X:
    348       case fixup_Hexagon_B15_PCREL:
    349       case fixup_Hexagon_B15_PCREL_X:
    350       case fixup_Hexagon_B13_PCREL:
    351       case fixup_Hexagon_B13_PCREL_X:
    352       case fixup_Hexagon_B9_PCREL:
    353       case fixup_Hexagon_B9_PCREL_X:
    354       case fixup_Hexagon_B7_PCREL:
    355       case fixup_Hexagon_B7_PCREL_X:
    356       case fixup_Hexagon_GD_PLT_B32_PCREL_X:
    357       case fixup_Hexagon_LD_PLT_B32_PCREL_X:
    358         return 4;
    359     }
    360   }
    361 
    362   // Make up for left shift when encoding the operand.
    363   static uint64_t adjustFixupValue(MCFixupKind Kind, uint64_t Value) {
    364     switch((unsigned)Kind) {
    365       default:
    366         break;
    367 
    368       case fixup_Hexagon_B7_PCREL:
    369       case fixup_Hexagon_B9_PCREL:
    370       case fixup_Hexagon_B13_PCREL:
    371       case fixup_Hexagon_B15_PCREL:
    372       case fixup_Hexagon_B22_PCREL:
    373         Value >>= 2;
    374         break;
    375 
    376       case fixup_Hexagon_B7_PCREL_X:
    377       case fixup_Hexagon_B9_PCREL_X:
    378       case fixup_Hexagon_B13_PCREL_X:
    379       case fixup_Hexagon_B15_PCREL_X:
    380       case fixup_Hexagon_B22_PCREL_X:
    381         Value &= 0x3f;
    382         break;
    383 
    384       case fixup_Hexagon_B32_PCREL_X:
    385       case fixup_Hexagon_GD_PLT_B32_PCREL_X:
    386       case fixup_Hexagon_LD_PLT_B32_PCREL_X:
    387         Value >>= 6;
    388         break;
    389     }
    390     return (Value);
    391   }
    392 
    393   void HandleFixupError(const int bits, const int align_bits,
    394     const int64_t FixupValue, const char *fixupStr) const {
    395     // Error: value 1124 out of range: -1024-1023 when resolving
    396     // symbol in file xprtsock.S
    397     const APInt IntMin = APInt::getSignedMinValue(bits+align_bits);
    398     const APInt IntMax = APInt::getSignedMaxValue(bits+align_bits);
    399     std::stringstream errStr;
    400     errStr << "\nError: value " <<
    401       FixupValue <<
    402       " out of range: " <<
    403       IntMin.getSExtValue() <<
    404       "-" <<
    405       IntMax.getSExtValue() <<
    406       " when resolving " <<
    407       fixupStr <<
    408       " fixup\n";
    409     llvm_unreachable(errStr.str().c_str());
    410   }
    411 
    412   /// ApplyFixup - Apply the \arg Value for given \arg Fixup into the provided
    413   /// data fragment, at the offset specified by the fixup and following the
    414   /// fixup kind as appropriate.
    415   void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
    416                   const MCValue &Target, MutableArrayRef<char> Data,
    417                   uint64_t FixupValue, bool IsResolved,
    418                   const MCSubtargetInfo *STI) const override {
    419 
    420     // When FixupValue is 0 the relocation is external and there
    421     // is nothing for us to do.
    422     if (!FixupValue) return;
    423 
    424     MCFixupKind Kind = Fixup.getKind();
    425     uint64_t Value;
    426     uint32_t InstMask;
    427     uint32_t Reloc;
    428 
    429     // LLVM gives us an encoded value, we have to convert it back
    430     // to a real offset before we can use it.
    431     uint32_t Offset = Fixup.getOffset();
    432     unsigned NumBytes = getFixupKindNumBytes(Kind);
    433     assert(Offset + NumBytes <= Data.size() && "Invalid fixup offset!");
    434     char *InstAddr = Data.data() + Offset;
    435 
    436     Value = adjustFixupValue(Kind, FixupValue);
    437     if(!Value)
    438       return;
    439     int sValue = (int)Value;
    440 
    441     switch((unsigned)Kind) {
    442       default:
    443         return;
    444 
    445       case fixup_Hexagon_B7_PCREL:
    446         if (!(isIntN(7, sValue)))
    447           HandleFixupError(7, 2, (int64_t)FixupValue, "B7_PCREL");
    448         LLVM_FALLTHROUGH;
    449       case fixup_Hexagon_B7_PCREL_X:
    450         InstMask = 0x00001f18;  // Word32_B7
    451         Reloc = (((Value >> 2) & 0x1f) << 8) |    // Value 6-2 = Target 12-8
    452                 ((Value & 0x3) << 3);             // Value 1-0 = Target 4-3
    453         break;
    454 
    455       case fixup_Hexagon_B9_PCREL:
    456         if (!(isIntN(9, sValue)))
    457           HandleFixupError(9, 2, (int64_t)FixupValue, "B9_PCREL");
    458         LLVM_FALLTHROUGH;
    459       case fixup_Hexagon_B9_PCREL_X:
    460         InstMask = 0x003000fe;  // Word32_B9
    461         Reloc = (((Value >> 7) & 0x3) << 20) |    // Value 8-7 = Target 21-20
    462                 ((Value & 0x7f) << 1);            // Value 6-0 = Target 7-1
    463         break;
    464 
    465         // Since the existing branches that use this relocation cannot be
    466         // extended, they should only be fixed up if the target is within range.
    467       case fixup_Hexagon_B13_PCREL:
    468         if (!(isIntN(13, sValue)))
    469           HandleFixupError(13, 2, (int64_t)FixupValue, "B13_PCREL");
    470         LLVM_FALLTHROUGH;
    471       case fixup_Hexagon_B13_PCREL_X:
    472         InstMask = 0x00202ffe;  // Word32_B13
    473         Reloc = (((Value >> 12) & 0x1) << 21) |    // Value 12   = Target 21
    474                 (((Value >> 11) & 0x1) << 13) |    // Value 11   = Target 13
    475                 ((Value & 0x7ff) << 1);            // Value 10-0 = Target 11-1
    476         break;
    477 
    478       case fixup_Hexagon_B15_PCREL:
    479         if (!(isIntN(15, sValue)))
    480           HandleFixupError(15, 2, (int64_t)FixupValue, "B15_PCREL");
    481         LLVM_FALLTHROUGH;
    482       case fixup_Hexagon_B15_PCREL_X:
    483         InstMask = 0x00df20fe;  // Word32_B15
    484         Reloc = (((Value >> 13) & 0x3) << 22) |    // Value 14-13 = Target 23-22
    485                 (((Value >> 8) & 0x1f) << 16) |    // Value 12-8  = Target 20-16
    486                 (((Value >> 7) & 0x1)  << 13) |    // Value 7     = Target 13
    487                 ((Value & 0x7f) << 1);             // Value 6-0   = Target 7-1
    488         break;
    489 
    490       case fixup_Hexagon_B22_PCREL:
    491         if (!(isIntN(22, sValue)))
    492           HandleFixupError(22, 2, (int64_t)FixupValue, "B22_PCREL");
    493         LLVM_FALLTHROUGH;
    494       case fixup_Hexagon_B22_PCREL_X:
    495         InstMask = 0x01ff3ffe;  // Word32_B22
    496         Reloc = (((Value >> 13) & 0x1ff) << 16) |  // Value 21-13 = Target 24-16
    497                 ((Value & 0x1fff) << 1);           // Value 12-0  = Target 13-1
    498         break;
    499 
    500       case fixup_Hexagon_B32_PCREL_X:
    501         InstMask = 0x0fff3fff;  // Word32_X26
    502         Reloc = (((Value >> 14) & 0xfff) << 16) |  // Value 25-14 = Target 27-16
    503                 (Value & 0x3fff);                  // Value 13-0  = Target 13-0
    504         break;
    505 
    506       case FK_Data_1:
    507       case FK_Data_2:
    508       case FK_Data_4:
    509       case fixup_Hexagon_32:
    510         InstMask = 0xffffffff;  // Word32
    511         Reloc = Value;
    512         break;
    513     }
    514 
    515     LLVM_DEBUG(dbgs() << "Name=" << getFixupKindInfo(Kind).Name << "("
    516                       << (unsigned)Kind << ")\n");
    517     LLVM_DEBUG(
    518         uint32_t OldData = 0; for (unsigned i = 0; i < NumBytes; i++) OldData |=
    519                               (InstAddr[i] << (i * 8)) & (0xff << (i * 8));
    520         dbgs() << "\tBValue=0x"; dbgs().write_hex(Value) << ": AValue=0x";
    521         dbgs().write_hex(FixupValue)
    522         << ": Offset=" << Offset << ": Size=" << Data.size() << ": OInst=0x";
    523         dbgs().write_hex(OldData) << ": Reloc=0x"; dbgs().write_hex(Reloc););
    524 
    525     // For each byte of the fragment that the fixup touches, mask in the
    526     // bits from the fixup value. The Value has been "split up" into the
    527     // appropriate bitfields above.
    528     for (unsigned i = 0; i < NumBytes; i++){
    529       InstAddr[i] &= uint8_t(~InstMask >> (i * 8)) & 0xff; // Clear reloc bits
    530       InstAddr[i] |= uint8_t(Reloc >> (i * 8)) & 0xff;     // Apply new reloc
    531     }
    532 
    533     LLVM_DEBUG(uint32_t NewData = 0;
    534                for (unsigned i = 0; i < NumBytes; i++) NewData |=
    535                (InstAddr[i] << (i * 8)) & (0xff << (i * 8));
    536                dbgs() << ": NInst=0x"; dbgs().write_hex(NewData) << "\n";);
    537   }
    538 
    539   bool isInstRelaxable(MCInst const &HMI) const {
    540     const MCInstrDesc &MCID = HexagonMCInstrInfo::getDesc(*MCII, HMI);
    541     bool Relaxable = false;
    542     // Branches and loop-setup insns are handled as necessary by relaxation.
    543     if (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeJ ||
    544         (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeCJ &&
    545          MCID.isBranch()) ||
    546         (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeNCJ &&
    547          MCID.isBranch()) ||
    548         (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeCR &&
    549          HMI.getOpcode() != Hexagon::C4_addipc))
    550       if (HexagonMCInstrInfo::isExtendable(*MCII, HMI)) {
    551         Relaxable = true;
    552         MCOperand const &Operand =
    553             HMI.getOperand(HexagonMCInstrInfo::getExtendableOp(*MCII, HMI));
    554         if (HexagonMCInstrInfo::mustNotExtend(*Operand.getExpr()))
    555           Relaxable = false;
    556       }
    557 
    558     return Relaxable;
    559   }
    560 
    561   /// MayNeedRelaxation - Check whether the given instruction may need
    562   /// relaxation.
    563   ///
    564   /// \param Inst - The instruction to test.
    565   bool mayNeedRelaxation(MCInst const &Inst,
    566                          const MCSubtargetInfo &STI) const override {
    567     return true;
    568   }
    569 
    570   /// fixupNeedsRelaxation - Target specific predicate for whether a given
    571   /// fixup requires the associated instruction to be relaxed.
    572   bool fixupNeedsRelaxationAdvanced(const MCFixup &Fixup, bool Resolved,
    573                                     uint64_t Value,
    574                                     const MCRelaxableFragment *DF,
    575                                     const MCAsmLayout &Layout,
    576                                     const bool WasForced) const override {
    577     MCInst const &MCB = DF->getInst();
    578     assert(HexagonMCInstrInfo::isBundle(MCB));
    579 
    580     *RelaxTarget = nullptr;
    581     MCInst &MCI = const_cast<MCInst &>(HexagonMCInstrInfo::instruction(
    582         MCB, Fixup.getOffset() / HEXAGON_INSTR_SIZE));
    583     bool Relaxable = isInstRelaxable(MCI);
    584     if (Relaxable == false)
    585       return false;
    586     // If we cannot resolve the fixup value, it requires relaxation.
    587     if (!Resolved) {
    588       switch ((unsigned)Fixup.getKind()) {
    589       case fixup_Hexagon_B22_PCREL:
    590         // GetFixupCount assumes B22 won't relax
    591         LLVM_FALLTHROUGH;
    592       default:
    593         return false;
    594         break;
    595       case fixup_Hexagon_B13_PCREL:
    596       case fixup_Hexagon_B15_PCREL:
    597       case fixup_Hexagon_B9_PCREL:
    598       case fixup_Hexagon_B7_PCREL: {
    599         if (HexagonMCInstrInfo::bundleSize(MCB) < HEXAGON_PACKET_SIZE) {
    600           ++relaxedCnt;
    601           *RelaxTarget = &MCI;
    602           setExtender(Layout.getAssembler().getContext());
    603           return true;
    604         } else {
    605           return false;
    606         }
    607         break;
    608       }
    609       }
    610     }
    611 
    612     MCFixupKind Kind = Fixup.getKind();
    613     int64_t sValue = Value;
    614     int64_t maxValue;
    615 
    616     switch ((unsigned)Kind) {
    617     case fixup_Hexagon_B7_PCREL:
    618       maxValue = 1 << 8;
    619       break;
    620     case fixup_Hexagon_B9_PCREL:
    621       maxValue = 1 << 10;
    622       break;
    623     case fixup_Hexagon_B15_PCREL:
    624       maxValue = 1 << 16;
    625       break;
    626     case fixup_Hexagon_B22_PCREL:
    627       maxValue = 1 << 23;
    628       break;
    629     default:
    630       maxValue = INT64_MAX;
    631       break;
    632     }
    633 
    634     bool isFarAway = -maxValue > sValue || sValue > maxValue - 1;
    635 
    636     if (isFarAway) {
    637       if (HexagonMCInstrInfo::bundleSize(MCB) < HEXAGON_PACKET_SIZE) {
    638         ++relaxedCnt;
    639         *RelaxTarget = &MCI;
    640         setExtender(Layout.getAssembler().getContext());
    641         return true;
    642       }
    643     }
    644 
    645     return false;
    646   }
    647 
    648   /// Simple predicate for targets where !Resolved implies requiring relaxation
    649   bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
    650                             const MCRelaxableFragment *DF,
    651                             const MCAsmLayout &Layout) const override {
    652     llvm_unreachable("Handled by fixupNeedsRelaxationAdvanced");
    653   }
    654 
    655   void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
    656                         MCInst &Res) const override {
    657     assert(HexagonMCInstrInfo::isBundle(Inst) &&
    658            "Hexagon relaxInstruction only works on bundles");
    659 
    660     Res.setOpcode(Hexagon::BUNDLE);
    661     Res.addOperand(MCOperand::createImm(Inst.getOperand(0).getImm()));
    662     // Copy the results into the bundle.
    663     bool Update = false;
    664     for (auto &I : HexagonMCInstrInfo::bundleInstructions(Inst)) {
    665       MCInst &CrntHMI = const_cast<MCInst &>(*I.getInst());
    666 
    667       // if immediate extender needed, add it in
    668       if (*RelaxTarget == &CrntHMI) {
    669         Update = true;
    670         assert((HexagonMCInstrInfo::bundleSize(Res) < HEXAGON_PACKET_SIZE) &&
    671                "No room to insert extender for relaxation");
    672 
    673         MCInst *HMIx = takeExtender();
    674         *HMIx = HexagonMCInstrInfo::deriveExtender(
    675                 *MCII, CrntHMI,
    676                 HexagonMCInstrInfo::getExtendableOperand(*MCII, CrntHMI));
    677         Res.addOperand(MCOperand::createInst(HMIx));
    678         *RelaxTarget = nullptr;
    679       }
    680       // now copy over the original instruction(the one we may have extended)
    681       Res.addOperand(MCOperand::createInst(I.getInst()));
    682     }
    683     (void)Update;
    684     assert(Update && "Didn't find relaxation target");
    685   }
    686 
    687   bool writeNopData(raw_ostream &OS, uint64_t Count) const override {
    688     static const uint32_t Nopcode  = 0x7f000000, // Hard-coded NOP.
    689                           ParseIn  = 0x00004000, // In packet parse-bits.
    690                           ParseEnd = 0x0000c000; // End of packet parse-bits.
    691 
    692     while(Count % HEXAGON_INSTR_SIZE) {
    693       LLVM_DEBUG(dbgs() << "Alignment not a multiple of the instruction size:"
    694                         << Count % HEXAGON_INSTR_SIZE << "/"
    695                         << HEXAGON_INSTR_SIZE << "\n");
    696       --Count;
    697       OS << '\0';
    698     }
    699 
    700     while(Count) {
    701       Count -= HEXAGON_INSTR_SIZE;
    702       // Close the packet whenever a multiple of the maximum packet size remains
    703       uint32_t ParseBits = (Count % (HEXAGON_PACKET_SIZE * HEXAGON_INSTR_SIZE))?
    704                            ParseIn: ParseEnd;
    705       support::endian::write<uint32_t>(OS, Nopcode | ParseBits, Endian);
    706     }
    707     return true;
    708   }
    709 
    710   void finishLayout(MCAssembler const &Asm,
    711                     MCAsmLayout &Layout) const override {
    712     for (auto I : Layout.getSectionOrder()) {
    713       auto &Fragments = I->getFragmentList();
    714       for (auto &J : Fragments) {
    715         switch (J.getKind()) {
    716         default:
    717           break;
    718         case MCFragment::FT_Align: {
    719           auto Size = Asm.computeFragmentSize(Layout, J);
    720           for (auto K = J.getIterator();
    721                K != Fragments.begin() && Size >= HEXAGON_PACKET_SIZE;) {
    722             --K;
    723             switch (K->getKind()) {
    724             default:
    725               break;
    726             case MCFragment::FT_Align: {
    727               // Don't pad before other alignments
    728               Size = 0;
    729               break;
    730             }
    731             case MCFragment::FT_Relaxable: {
    732               MCContext &Context = Asm.getContext();
    733               auto &RF = cast<MCRelaxableFragment>(*K);
    734               auto &Inst = const_cast<MCInst &>(RF.getInst());
    735               while (Size > 0 && HexagonMCInstrInfo::bundleSize(Inst) < 4) {
    736                 MCInst *Nop = new (Context) MCInst;
    737                 Nop->setOpcode(Hexagon::A2_nop);
    738                 Inst.addOperand(MCOperand::createInst(Nop));
    739                 Size -= 4;
    740                 if (!HexagonMCChecker(
    741                          Context, *MCII, *RF.getSubtargetInfo(), Inst,
    742                          *Context.getRegisterInfo(), false)
    743                          .check()) {
    744                   Inst.erase(Inst.end() - 1);
    745                   Size = 0;
    746                 }
    747               }
    748               bool Error = HexagonMCShuffle(Context, true, *MCII,
    749                                             *RF.getSubtargetInfo(), Inst);
    750               //assert(!Error);
    751               (void)Error;
    752               ReplaceInstruction(Asm.getEmitter(), RF, Inst);
    753               Layout.invalidateFragmentsFrom(&RF);
    754               Size = 0; // Only look back one instruction
    755               break;
    756             }
    757             }
    758           }
    759         }
    760         }
    761       }
    762     }
    763   }
    764 }; // class HexagonAsmBackend
    765 
    766 } // namespace
    767 
    768 // MCAsmBackend
    769 MCAsmBackend *llvm::createHexagonAsmBackend(Target const &T,
    770                                             const MCSubtargetInfo &STI,
    771                                             MCRegisterInfo const & /*MRI*/,
    772                                             const MCTargetOptions &Options) {
    773   const Triple &TT = STI.getTargetTriple();
    774   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
    775 
    776   StringRef CPUString = Hexagon_MC::selectHexagonCPU(STI.getCPU());
    777   return new HexagonAsmBackend(T, TT, OSABI, CPUString);
    778 }
    779