lib/Target/PowerPC/PPCCodeEmitter.cpp

   1 //===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC32 -------*- C++ -*-=//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source 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 bytecode 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/MachineFunctionPass.h"
  22 #include "llvm/CodeGen/MachineInstrBuilder.h"
  23 #include "llvm/CodeGen/Passes.h"
  24 #include "llvm/Support/Debug.h"
  25 #include "llvm/Support/Compiler.h"
  26 #include "llvm/Target/TargetOptions.h"
  27 using namespace llvm;
  28
  29 namespace {
  30   class VISIBILITY_HIDDEN PPCCodeEmitter : public MachineFunctionPass {
  31     TargetMachine &TM;
  32     MachineCodeEmitter &MCE;
  33
  34     /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
  35     /// its address in the function into this pointer.
  36     void *MovePCtoLROffset;
  37
  38     /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
  39     ///
  40     int getMachineOpValue(MachineInstr &MI, MachineOperand &MO);
  41
  42   public:
  43     static char ID;
  44     PPCCodeEmitter(TargetMachine &T, MachineCodeEmitter &M)
  45       : MachineFunctionPass((intptr_t)&ID), TM(T), MCE(M) {}
  46
  47     const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
  48
  49     /// runOnMachineFunction - emits the given MachineFunction to memory
  50     ///
  51     bool runOnMachineFunction(MachineFunction &MF);
  52
  53     /// emitBasicBlock - emits the given MachineBasicBlock to memory
  54     ///
  55     void emitBasicBlock(MachineBasicBlock &MBB);
  56
  57     /// getValueBit - return the particular bit of Val
  58     ///
  59     unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
  60
  61     /// getBinaryCodeForInstr - This function, generated by the
  62     /// CodeEmitterGenerator using TableGen, produces the binary encoding for
  63     /// machine instructions.
  64     ///
  65     unsigned getBinaryCodeForInstr(MachineInstr &MI);
  66   };
  67   char PPCCodeEmitter::ID = 0;
  68 }
  69
  70 /// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
  71 /// to the specified MCE object.
  72 FunctionPass *llvm::createPPCCodeEmitterPass(PPCTargetMachine &TM,
  73                                              MachineCodeEmitter &MCE) {
  74   return new PPCCodeEmitter(TM, MCE);
  75 }
  76
  77 #ifdef __APPLE__
  78 extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
  79 #endif
  80
  81 bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
  82   assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
  83           MF.getTarget().getRelocationModel() != Reloc::Static) &&
  84          "JIT relocation model must be set to static or default!");
  85   do {
  86     MovePCtoLROffset = 0;
  87     MCE.startFunction(MF);
  88     for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
  89       emitBasicBlock(*BB);
  90   } while (MCE.finishFunction(MF));
  91
  92   return false;
  93 }
  94
  95 void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
  96   MCE.StartMachineBasicBlock(&MBB);
  97
  98   for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
  99     MachineInstr &MI = *I;
 100     switch (MI.getOpcode()) {
 101     default:
 102       MCE.emitWordBE(getBinaryCodeForInstr(*I));
 103       break;
 104     case PPC::IMPLICIT_DEF_GPRC:
 105     case PPC::IMPLICIT_DEF_G8RC:
 106     case PPC::IMPLICIT_DEF_F8:
 107     case PPC::IMPLICIT_DEF_F4:
 108     case PPC::IMPLICIT_DEF_VRRC:
 109       break; // pseudo opcode, no side effects
 110     case PPC::MovePCtoLR:
 111     case PPC::MovePCtoLR8:
 112       assert(TM.getRelocationModel() == Reloc::PIC_);
 113       MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
 114       MCE.emitWordBE(0x48000005);   // bl 1
 115       break;
 116     }
 117   }
 118 }
 119
 120 int PPCCodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
 121
 122   intptr_t rv = 0; // Return value; defaults to 0 for unhandled cases
 123                    // or things that get fixed up later by the JIT.
 124   if (MO.isRegister()) {
 125     rv = PPCRegisterInfo::getRegisterNumbering(MO.getReg());
 126
 127     // Special encoding for MTCRF and MFOCRF, which uses a bit mask for the
 128     // register, not the register number directly.
 129     if ((MI.getOpcode() == PPC::MTCRF || MI.getOpcode() == PPC::MFOCRF) &&
 130         (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7)) {
 131       rv = 0x80 >> rv;
 132     }
 133   } else if (MO.isImmediate()) {
 134     rv = MO.getImmedValue();
 135   } else if (MO.isGlobalAddress() || MO.isExternalSymbol() ||
 136              MO.isConstantPoolIndex() || MO.isJumpTableIndex()) {
 137     unsigned Reloc = 0;
 138     if (MI.getOpcode() == PPC::BL_Macho || MI.getOpcode() == PPC::BL8_Macho ||
 139         MI.getOpcode() == PPC::BL_ELF || MI.getOpcode() == PPC::BL8_ELF)
 140       Reloc = PPC::reloc_pcrel_bx;
 141     else {
 142       if (TM.getRelocationModel() == Reloc::PIC_) {
 143         assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
 144       }
 145       switch (MI.getOpcode()) {
 146       default: MI.dump(); assert(0 && "Unknown instruction for relocation!");
 147       case PPC::LIS:
 148       case PPC::LIS8:
 149       case PPC::ADDIS:
 150       case PPC::ADDIS8:
 151         Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
 152         break;
 153       case PPC::LI:
 154       case PPC::LI8:
 155       case PPC::LA:
 156       // Loads.
 157       case PPC::LBZ:
 158       case PPC::LBZ8:
 159       case PPC::LHA:
 160       case PPC::LHA8:
 161       case PPC::LHZ:
 162       case PPC::LHZ8:
 163       case PPC::LWZ:
 164       case PPC::LWZ8:
 165       case PPC::LFS:
 166       case PPC::LFD:
 167
 168       // Stores.
 169       case PPC::STB:
 170       case PPC::STB8:
 171       case PPC::STH:
 172       case PPC::STH8:
 173       case PPC::STW:
 174       case PPC::STW8:
 175       case PPC::STFS:
 176       case PPC::STFD:
 177         Reloc = PPC::reloc_absolute_low;
 178         break;
 179
 180       case PPC::LWA:
 181       case PPC::LD:
 182       case PPC::STD:
 183       case PPC::STD_32:
 184         Reloc = PPC::reloc_absolute_low_ix;
 185         break;
 186       }
 187     }
 188
 189     MachineRelocation R;
 190     if (MO.isGlobalAddress()) {
 191       R = MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
 192                                    MO.getGlobal(), 0);
 193     } else if (MO.isExternalSymbol()) {
 194       R = MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
 195                                        Reloc, MO.getSymbolName(), 0);
 196     } else if (MO.isConstantPoolIndex()) {
 197       R = MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
 198                                           Reloc, MO.getConstantPoolIndex(), 0);
 199     } else {
 200       assert(MO.isJumpTableIndex());
 201       R = MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
 202                                           Reloc, MO.getJumpTableIndex(), 0);
 203     }
 204
 205     // If in PIC mode, we need to encode the negated address of the
 206     // 'movepctolr' into the unrelocated field.  After relocation, we'll have
 207     // &gv-&movepctolr-4 in the imm field.  Once &movepctolr is added to the imm
 208     // field, we get &gv.  This doesn't happen for branch relocations, which are
 209     // always implicitly pc relative.
 210     if (TM.getRelocationModel() == Reloc::PIC_ && Reloc != PPC::reloc_pcrel_bx){
 211       assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
 212       R.setConstantVal(-(intptr_t)MovePCtoLROffset - 4);
 213     }
 214     MCE.addRelocation(R);
 215
 216   } else if (MO.isMachineBasicBlock()) {
 217     unsigned Reloc = 0;
 218     unsigned Opcode = MI.getOpcode();
 219     if (Opcode == PPC::B || Opcode == PPC::BL_Macho ||
 220         Opcode == PPC::BLA_Macho || Opcode == PPC::BL_ELF ||
 221         Opcode == PPC::BLA_ELF)
 222       Reloc = PPC::reloc_pcrel_bx;
 223     else // BCC instruction
 224       Reloc = PPC::reloc_pcrel_bcx;
 225     MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
 226                                                Reloc,
 227                                                MO.getMachineBasicBlock()));
 228   } else {
 229     cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
 230     abort();
 231   }
 232
 233   return rv;
 234 }
 235
 236 #include "PPCGenCodeEmitter.inc"
 237