lib/Target/PowerPC/PPCCodeEmitter.cpp

   1 //===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC32 -------*- C++ -*-=//
   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 // This file defines the PowerPC 32-bit CodeEmitter and associated machinery to
  11 // JIT-compile bitcode to native PowerPC.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "PPCTargetMachine.h"
  16 #include "PPCRelocations.h"
  17 #include "PPC.h"
  18 #include "llvm/Module.h"
  19 #include "llvm/PassManager.h"
  20 #include "llvm/CodeGen/MachineCodeEmitter.h"
  21 #include "llvm/CodeGen/JITCodeEmitter.h"
  22 #include "llvm/CodeGen/ObjectCodeEmitter.h"
  23 #include "llvm/CodeGen/MachineFunctionPass.h"
  24 #include "llvm/CodeGen/MachineInstrBuilder.h"
  25 #include "llvm/CodeGen/MachineModuleInfo.h"
  26 #include "llvm/CodeGen/Passes.h"
  27 #include "llvm/Support/Debug.h"
  28 #include "llvm/Support/Compiler.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include "llvm/Target/TargetOptions.h"
  32 using namespace llvm;
  33
  34 namespace {
  35   class PPCCodeEmitter {
  36     TargetMachine &TM;
  37     MachineCodeEmitter &MCE;
  38   public:
  39     PPCCodeEmitter(TargetMachine &tm, MachineCodeEmitter &mce):
  40         TM(tm), MCE(mce) {}
  41
  42     /// getBinaryCodeForInstr - This function, generated by the
  43     /// CodeEmitterGenerator using TableGen, produces the binary encoding for
  44     /// machine instructions.
  45
  46     unsigned getBinaryCodeForInstr(const MachineInstr &MI);
  47
  48     /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
  49
  50     unsigned getMachineOpValue(const MachineInstr &MI,
  51                                const MachineOperand &MO);
  52
  53     /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
  54     /// its address in the function into this pointer.
  55
  56     void *MovePCtoLROffset;
  57   };
  58
  59   template <class CodeEmitter>
  60   class VISIBILITY_HIDDEN Emitter : public MachineFunctionPass,
  61       public PPCCodeEmitter {
  62     TargetMachine &TM;
  63     CodeEmitter &MCE;
  64
  65     void getAnalysisUsage(AnalysisUsage &AU) const {
  66       AU.addRequired<MachineModuleInfo>();
  67       MachineFunctionPass::getAnalysisUsage(AU);
  68     }
  69
  70   public:
  71     static char ID;
  72     Emitter(TargetMachine &tm, CodeEmitter &mce)
  73       : MachineFunctionPass(&ID), PPCCodeEmitter(tm, mce), TM(tm), MCE(mce) {}
  74
  75     const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
  76
  77     /// runOnMachineFunction - emits the given MachineFunction to memory
  78     ///
  79     bool runOnMachineFunction(MachineFunction &MF);
  80
  81     /// emitBasicBlock - emits the given MachineBasicBlock to memory
  82     ///
  83     void emitBasicBlock(MachineBasicBlock &MBB);
  84
  85     /// getValueBit - return the particular bit of Val
  86     ///
  87     unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
  88   };
  89
  90   template <class CodeEmitter>
  91     char Emitter<CodeEmitter>::ID = 0;
  92 }
  93
  94 /// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
  95 /// to the specified MCE object.
  96
  97 FunctionPass *llvm::createPPCCodeEmitterPass(PPCTargetMachine &TM,
  98                                              MachineCodeEmitter &MCE) {
  99   return new Emitter<MachineCodeEmitter>(TM, MCE);
 100 }
 101
 102 FunctionPass *llvm::createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
 103                                                 JITCodeEmitter &JCE) {
 104   return new Emitter<JITCodeEmitter>(TM, JCE);
 105 }
 106
 107 FunctionPass *llvm::createPPCObjectCodeEmitterPass(PPCTargetMachine &TM,
 108                                                    ObjectCodeEmitter &OCE) {
 109   return new Emitter<ObjectCodeEmitter>(TM, OCE);
 110 }
 111
 112 template <class CodeEmitter>
 113 bool Emitter<CodeEmitter>::runOnMachineFunction(MachineFunction &MF) {
 114   assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
 115           MF.getTarget().getRelocationModel() != Reloc::Static) &&
 116          "JIT relocation model must be set to static or default!");
 117
 118   MCE.setModuleInfo(&getAnalysis<MachineModuleInfo>());
 119   do {
 120     MovePCtoLROffset = 0;
 121     MCE.startFunction(MF);
 122     for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
 123       emitBasicBlock(*BB);
 124   } while (MCE.finishFunction(MF));
 125
 126   return false;
 127 }
 128
 129 template <class CodeEmitter>
 130 void Emitter<CodeEmitter>::emitBasicBlock(MachineBasicBlock &MBB) {
 131   MCE.StartMachineBasicBlock(&MBB);
 132
 133   for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
 134     const MachineInstr &MI = *I;
 135     MCE.processDebugLoc(MI.getDebugLoc());
 136     switch (MI.getOpcode()) {
 137     default:
 138       MCE.emitWordBE(getBinaryCodeForInstr(MI));
 139       break;
 140     case TargetInstrInfo::DBG_LABEL:
 141     case TargetInstrInfo::EH_LABEL:
 142       MCE.emitLabel(MI.getOperand(0).getImm());
 143       break;
 144     case TargetInstrInfo::IMPLICIT_DEF:
 145       break; // pseudo opcode, no side effects
 146     case PPC::MovePCtoLR:
 147     case PPC::MovePCtoLR8:
 148       assert(TM.getRelocationModel() == Reloc::PIC_);
 149       MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
 150       MCE.emitWordBE(0x48000005);   // bl 1
 151       break;
 152     }
 153   }
 154 }
 155
 156 unsigned PPCCodeEmitter::getMachineOpValue(const MachineInstr &MI,
 157                                            const MachineOperand &MO) {
 158
 159   unsigned rv = 0; // Return value; defaults to 0 for unhandled cases
 160                    // or things that get fixed up later by the JIT.
 161   if (MO.isReg()) {
 162     rv = PPCRegisterInfo::getRegisterNumbering(MO.getReg());
 163
 164     // Special encoding for MTCRF and MFOCRF, which uses a bit mask for the
 165     // register, not the register number directly.
 166     if ((MI.getOpcode() == PPC::MTCRF || MI.getOpcode() == PPC::MFOCRF) &&
 167         (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7)) {
 168       rv = 0x80 >> rv;
 169     }
 170   } else if (MO.isImm()) {
 171     rv = MO.getImm();
 172   } else if (MO.isGlobal() || MO.isSymbol() ||
 173              MO.isCPI() || MO.isJTI()) {
 174     unsigned Reloc = 0;
 175     if (MI.getOpcode() == PPC::BL_Darwin || MI.getOpcode() == PPC::BL8_Darwin ||
 176         MI.getOpcode() == PPC::BL_SVR4 || MI.getOpcode() == PPC::BL8_ELF ||
 177         MI.getOpcode() == PPC::TAILB || MI.getOpcode() == PPC::TAILB8)
 178       Reloc = PPC::reloc_pcrel_bx;
 179     else {
 180       if (TM.getRelocationModel() == Reloc::PIC_) {
 181         assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
 182       }
 183       switch (MI.getOpcode()) {
 184       default: MI.dump(); llvm_unreachable("Unknown instruction for relocation!");
 185       case PPC::LIS:
 186       case PPC::LIS8:
 187       case PPC::ADDIS:
 188       case PPC::ADDIS8:
 189         Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
 190         break;
 191       case PPC::LI:
 192       case PPC::LI8:
 193       case PPC::LA:
 194       // Loads.
 195       case PPC::LBZ:
 196       case PPC::LBZ8:
 197       case PPC::LHA:
 198       case PPC::LHA8:
 199       case PPC::LHZ:
 200       case PPC::LHZ8:
 201       case PPC::LWZ:
 202       case PPC::LWZ8:
 203       case PPC::LFS:
 204       case PPC::LFD:
 205
 206       // Stores.
 207       case PPC::STB:
 208       case PPC::STB8:
 209       case PPC::STH:
 210       case PPC::STH8:
 211       case PPC::STW:
 212       case PPC::STW8:
 213       case PPC::STFS:
 214       case PPC::STFD:
 215         Reloc = PPC::reloc_absolute_low;
 216         break;
 217
 218       case PPC::LWA:
 219       case PPC::LD:
 220       case PPC::STD:
 221       case PPC::STD_32:
 222         Reloc = PPC::reloc_absolute_low_ix;
 223         break;
 224       }
 225     }
 226
 227     MachineRelocation R;
 228     if (MO.isGlobal()) {
 229       R = MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
 230                                    MO.getGlobal(), 0,
 231                                    isa<Function>(MO.getGlobal()));
 232     } else if (MO.isSymbol()) {
 233       R = MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
 234                                        Reloc, MO.getSymbolName(), 0);
 235     } else if (MO.isCPI()) {
 236       R = MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
 237                                           Reloc, MO.getIndex(), 0);
 238     } else {
 239       assert(MO.isJTI());
 240       R = MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
 241                                           Reloc, MO.getIndex(), 0);
 242     }
 243
 244     // If in PIC mode, we need to encode the negated address of the
 245     // 'movepctolr' into the unrelocated field.  After relocation, we'll have
 246     // &gv-&movepctolr-4 in the imm field.  Once &movepctolr is added to the imm
 247     // field, we get &gv.  This doesn't happen for branch relocations, which are
 248     // always implicitly pc relative.
 249     if (TM.getRelocationModel() == Reloc::PIC_ && Reloc != PPC::reloc_pcrel_bx){
 250       assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
 251       R.setConstantVal(-(intptr_t)MovePCtoLROffset - 4);
 252     }
 253     MCE.addRelocation(R);
 254
 255   } else if (MO.isMBB()) {
 256     unsigned Reloc = 0;
 257     unsigned Opcode = MI.getOpcode();
 258     if (Opcode == PPC::B || Opcode == PPC::BL_Darwin ||
 259         Opcode == PPC::BLA_Darwin|| Opcode == PPC::BL_SVR4 ||
 260         Opcode == PPC::BLA_SVR4)
 261       Reloc = PPC::reloc_pcrel_bx;
 262     else // BCC instruction
 263       Reloc = PPC::reloc_pcrel_bcx;
 264
 265     MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
 266                                                Reloc, MO.getMBB()));
 267   } else {
 268 #ifndef NDEBUG
 269     errs() << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
 270 #endif
 271     llvm_unreachable(0);
 272   }
 273
 274   return rv;
 275 }
 276
 277 #include "PPCGenCodeEmitter.inc"