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