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/ErrorHandling.h"
  29 #include "llvm/Support/raw_ostream.h"
  30 #include "llvm/Target/TargetOptions.h"
  31 using namespace llvm;
  32
  33 namespace {
  34   class PPCCodeEmitter {
  35     TargetMachine &TM;
  36     MachineCodeEmitter &MCE;
  37   public:
  38     PPCCodeEmitter(TargetMachine &tm, MachineCodeEmitter &mce):
  39         TM(tm), MCE(mce) {}
  40
  41     /// getBinaryCodeForInstr - This function, generated by the
  42     /// CodeEmitterGenerator using TableGen, produces the binary encoding for
  43     /// machine instructions.
  44
  45     unsigned getBinaryCodeForInstr(const MachineInstr &MI);
  46
  47     /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
  48
  49     unsigned getMachineOpValue(const MachineInstr &MI,
  50                                const MachineOperand &MO);
  51
  52     /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
  53     /// its address in the function into this pointer.
  54
  55     void *MovePCtoLROffset;
  56   };
  57
  58   template <class CodeEmitter>
  59   class Emitter : public MachineFunctionPass, public PPCCodeEmitter {
  60     TargetMachine &TM;
  61     CodeEmitter &MCE;
  62
  63     void getAnalysisUsage(AnalysisUsage &AU) const {
  64       AU.addRequired<MachineModuleInfo>();
  65       MachineFunctionPass::getAnalysisUsage(AU);
  66     }
  67
  68   public:
  69     static char ID;
  70     Emitter(TargetMachine &tm, CodeEmitter &mce)
  71       : MachineFunctionPass(&ID), PPCCodeEmitter(tm, mce), TM(tm), MCE(mce) {}
  72
  73     const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
  74
  75     /// runOnMachineFunction - emits the given MachineFunction to memory
  76     ///
  77     bool runOnMachineFunction(MachineFunction &MF);
  78
  79     /// emitBasicBlock - emits the given MachineBasicBlock to memory
  80     ///
  81     void emitBasicBlock(MachineBasicBlock &MBB);
  82
  83     /// getValueBit - return the particular bit of Val
  84     ///
  85     unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
  86   };
  87
  88   template <class CodeEmitter>
  89     char Emitter<CodeEmitter>::ID = 0;
  90 }
  91
  92 /// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
  93 /// to the specified MCE object.
  94
  95 FunctionPass *llvm::createPPCCodeEmitterPass(PPCTargetMachine &TM,
  96                                              MachineCodeEmitter &MCE) {
  97   return new Emitter<MachineCodeEmitter>(TM, MCE);
  98 }
  99
 100 FunctionPass *llvm::createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
 101                                                 JITCodeEmitter &JCE) {
 102   return new Emitter<JITCodeEmitter>(TM, JCE);
 103 }
 104
 105 FunctionPass *llvm::createPPCObjectCodeEmitterPass(PPCTargetMachine &TM,
 106                                                    ObjectCodeEmitter &OCE) {
 107   return new Emitter<ObjectCodeEmitter>(TM, OCE);
 108 }
 109
 110 template <class CodeEmitter>
 111 bool Emitter<CodeEmitter>::runOnMachineFunction(MachineFunction &MF) {
 112   assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
 113           MF.getTarget().getRelocationModel() != Reloc::Static) &&
 114          "JIT relocation model must be set to static or default!");
 115
 116   MCE.setModuleInfo(&getAnalysis<MachineModuleInfo>());
 117   do {
 118     MovePCtoLROffset = 0;
 119     MCE.startFunction(MF);
 120     for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
 121       emitBasicBlock(*BB);
 122   } while (MCE.finishFunction(MF));
 123
 124   return false;
 125 }
 126
 127 template <class CodeEmitter>
 128 void Emitter<CodeEmitter>::emitBasicBlock(MachineBasicBlock &MBB) {
 129   MCE.StartMachineBasicBlock(&MBB);
 130
 131   for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
 132     const MachineInstr &MI = *I;
 133     MCE.processDebugLoc(MI.getDebugLoc(), true);
 134     switch (MI.getOpcode()) {
 135     default:
 136       MCE.emitWordBE(getBinaryCodeForInstr(MI));
 137       break;
 138     case TargetInstrInfo::DBG_LABEL:
 139     case TargetInstrInfo::EH_LABEL:
 140       MCE.emitLabel(MI.getOperand(0).getImm());
 141       break;
 142     case TargetInstrInfo::IMPLICIT_DEF:
 143     case TargetInstrInfo::KILL:
 144       break; // pseudo opcode, no side effects
 145     case PPC::MovePCtoLR:
 146     case PPC::MovePCtoLR8:
 147       assert(TM.getRelocationModel() == Reloc::PIC_);
 148       MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
 149       MCE.emitWordBE(0x48000005);   // bl 1
 150       break;
 151     }
 152     MCE.processDebugLoc(MI.getDebugLoc(), false);
 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"