/3rd_party/llvm/lib/Target/PowerPC/PPCCodeEmitter.cpp

  1//===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC -----------------===//
  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 "PPC.h"
 16#include "PPCRelocations.h"
 17#include "PPCTargetMachine.h"
 18#include "llvm/CodeGen/JITCodeEmitter.h"
 19#include "llvm/CodeGen/MachineFunctionPass.h"
 20#include "llvm/CodeGen/MachineInstrBuilder.h"
 21#include "llvm/CodeGen/MachineModuleInfo.h"
 22#include "llvm/IR/Module.h"
 23#include "llvm/PassManager.h"
 24#include "llvm/Support/ErrorHandling.h"
 25#include "llvm/Support/raw_ostream.h"
 26#include "llvm/Target/TargetOptions.h"
 27using namespace llvm;
 28
 29namespace {
 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    uint64_t getBinaryCodeForInstr(const MachineInstr &MI) const;
 54
 55    
 56    MachineRelocation GetRelocation(const MachineOperand &MO,
 57                                    unsigned RelocID) const;
 58    
 59    /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
 60    unsigned getMachineOpValue(const MachineInstr &MI,
 61                               const MachineOperand &MO) const;
 62
 63    unsigned get_crbitm_encoding(const MachineInstr &MI, unsigned OpNo) const;
 64    unsigned getDirectBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
 65    unsigned getCondBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
 66    unsigned getAbsDirectBrEncoding(const MachineInstr &MI,
 67                                    unsigned OpNo) const;
 68    unsigned getAbsCondBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
 69
 70    unsigned getImm16Encoding(const MachineInstr &MI, unsigned OpNo) const;
 71    unsigned getMemRIEncoding(const MachineInstr &MI, unsigned OpNo) const;
 72    unsigned getMemRIXEncoding(const MachineInstr &MI, unsigned OpNo) const;
 73    unsigned getTLSRegEncoding(const MachineInstr &MI, unsigned OpNo) const;
 74    unsigned getTLSCallEncoding(const MachineInstr &MI, unsigned OpNo) const;
 75
 76    const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
 77
 78    /// runOnMachineFunction - emits the given MachineFunction to memory
 79    ///
 80    bool runOnMachineFunction(MachineFunction &MF);
 81
 82    /// emitBasicBlock - emits the given MachineBasicBlock to memory
 83    ///
 84    void emitBasicBlock(MachineBasicBlock &MBB);
 85  };
 86}
 87
 88char PPCCodeEmitter::ID = 0;
 89
 90/// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
 91/// to the specified MCE object.
 92FunctionPass *llvm::createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
 93                                                JITCodeEmitter &JCE) {
 94  return new PPCCodeEmitter(TM, JCE);
 95}
 96
 97bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
 98  assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
 99          MF.getTarget().getRelocationModel() != Reloc::Static) &&
100         "JIT relocation model must be set to static or default!");
101
102  MMI = &getAnalysis<MachineModuleInfo>();
103  MCE.setModuleInfo(MMI);
104  do {
105    MovePCtoLROffset = 0;
106    MCE.startFunction(MF);
107    for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
108      emitBasicBlock(*BB);
109  } while (MCE.finishFunction(MF));
110
111  return false;
112}
113
114void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
115  MCE.StartMachineBasicBlock(&MBB);
116
117  for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
118    const MachineInstr &MI = *I;
119    MCE.processDebugLoc(MI.getDebugLoc(), true);
120    switch (MI.getOpcode()) {
121    default:
122      MCE.emitWordBE(getBinaryCodeForInstr(MI));
123      break;
124    case TargetOpcode::PROLOG_LABEL:
125    case TargetOpcode::EH_LABEL:
126      MCE.emitLabel(MI.getOperand(0).getMCSymbol());
127      break;
128    case TargetOpcode::IMPLICIT_DEF:
129    case TargetOpcode::KILL:
130      break; // pseudo opcode, no side effects
131    case PPC::MovePCtoLR:
132    case PPC::MovePCtoLR8:
133      assert(TM.getRelocationModel() == Reloc::PIC_);
134      MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
135      MCE.emitWordBE(0x48000005);   // bl 1
136      break;
137    }
138    MCE.processDebugLoc(MI.getDebugLoc(), false);
139  }
140}
141
142unsigned PPCCodeEmitter::get_crbitm_encoding(const MachineInstr &MI,
143                                             unsigned OpNo) const {
144  const MachineOperand &MO = MI.getOperand(OpNo);
145  assert((MI.getOpcode() == PPC::MTOCRF || MI.getOpcode() == PPC::MTOCRF8 ||
146          MI.getOpcode() == PPC::MFOCRF || MI.getOpcode() == PPC::MFOCRF8) &&
147         (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7));
148  return 0x80 >> TM.getRegisterInfo()->getEncodingValue(MO.getReg());
149}
150
151MachineRelocation PPCCodeEmitter::GetRelocation(const MachineOperand &MO, 
152                                                unsigned RelocID) const {
153  // If in PIC mode, we need to encode the negated address of the
154  // 'movepctolr' into the unrelocated field.  After relocation, we'll have
155  // &gv-&movepctolr-4 in the imm field.  Once &movepctolr is added to the imm
156  // field, we get &gv.  This doesn't happen for branch relocations, which are
157  // always implicitly pc relative.
158  intptr_t Cst = 0;
159  if (TM.getRelocationModel() == Reloc::PIC_) {
160    assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
161    Cst = -(intptr_t)MovePCtoLROffset - 4;
162  }
163  
164  if (MO.isGlobal())
165    return MachineRelocation::getGV(MCE.getCurrentPCOffset(), RelocID,
166                                    const_cast<GlobalValue *>(MO.getGlobal()),
167                                    Cst, isa<Function>(MO.getGlobal()));
168  if (MO.isSymbol())
169    return MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
170                                        RelocID, MO.getSymbolName(), Cst);
171  if (MO.isCPI())
172    return MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
173                                           RelocID, MO.getIndex(), Cst);
174
175  if (MO.isMBB())
176    return MachineRelocation::getBB(MCE.getCurrentPCOffset(),
177                                    RelocID, MO.getMBB());
178  
179  assert(MO.isJTI());
180  return MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
181                                         RelocID, MO.getIndex(), Cst);
182}
183
184unsigned PPCCodeEmitter::getDirectBrEncoding(const MachineInstr &MI,
185                                             unsigned OpNo) const {
186  const MachineOperand &MO = MI.getOperand(OpNo);
187  if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
188  
189  MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bx));
190  return 0;
191}
192
193unsigned PPCCodeEmitter::getCondBrEncoding(const MachineInstr &MI,
194                                           unsigned OpNo) const {
195  const MachineOperand &MO = MI.getOperand(OpNo);
196  MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bcx));
197  return 0;
198}
199
200unsigned PPCCodeEmitter::getAbsDirectBrEncoding(const MachineInstr &MI,
201                                                unsigned OpNo) const {
202  const MachineOperand &MO = MI.getOperand(OpNo);
203  if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
204
205  llvm_unreachable("Absolute branch relocations unsupported on the old JIT.");
206}
207
208unsigned PPCCodeEmitter::getAbsCondBrEncoding(const MachineInstr &MI,
209                                              unsigned OpNo) const {
210  llvm_unreachable("Absolute branch relocations unsupported on the old JIT.");
211}
212
213unsigned PPCCodeEmitter::getImm16Encoding(const MachineInstr &MI,
214                                          unsigned OpNo) const {
215  const MachineOperand &MO = MI.getOperand(OpNo);
216  if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
217
218  unsigned RelocID;
219  switch (MO.getTargetFlags() & PPCII::MO_ACCESS_MASK) {
220    default: llvm_unreachable("Unsupported target operand flags!");
221    case PPCII::MO_LO: RelocID = PPC::reloc_absolute_low; break;
222    case PPCII::MO_HA: RelocID = PPC::reloc_absolute_high; break;
223  }
224
225  MCE.addRelocation(GetRelocation(MO, RelocID));
226  return 0;
227}
228
229unsigned PPCCodeEmitter::getMemRIEncoding(const MachineInstr &MI,
230                                          unsigned OpNo) const {
231  // Encode (imm, reg) as a memri, which has the low 16-bits as the
232  // displacement and the next 5 bits as the register #.
233  assert(MI.getOperand(OpNo+1).isReg());
234  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 16;
235  
236  const MachineOperand &MO = MI.getOperand(OpNo);
237  if (MO.isImm())
238    return (getMachineOpValue(MI, MO) & 0xFFFF) | RegBits;
239  
240  // Add a fixup for the displacement field.
241  MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low));
242  return RegBits;
243}
244
245unsigned PPCCodeEmitter::getMemRIXEncoding(const MachineInstr &MI,
246                                           unsigned OpNo) const {
247  // Encode (imm, reg) as a memrix, which has the low 14-bits as the
248  // displacement and the next 5 bits as the register #.
249  assert(MI.getOperand(OpNo+1).isReg());
250  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 14;
251  
252  const MachineOperand &MO = MI.getOperand(OpNo);
253  if (MO.isImm())
254    return ((getMachineOpValue(MI, MO) >> 2) & 0x3FFF) | RegBits;
255  
256  MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low_ix));
257  return RegBits;
258}
259
260
261unsigned PPCCodeEmitter::getTLSRegEncoding(const MachineInstr &MI,
262                                           unsigned OpNo) const {
263  llvm_unreachable("TLS not supported on the old JIT.");
264  return 0;
265}
266
267unsigned PPCCodeEmitter::getTLSCallEncoding(const MachineInstr &MI,
268                                            unsigned OpNo) const {
269  llvm_unreachable("TLS not supported on the old JIT.");
270  return 0;
271}
272
273unsigned PPCCodeEmitter::getMachineOpValue(const MachineInstr &MI,
274                                           const MachineOperand &MO) const {
275
276  if (MO.isReg()) {
277    // MTOCRF/MFOCRF should go through get_crbitm_encoding for the CR operand.
278    // The GPR operand should come through here though.
279    assert((MI.getOpcode() != PPC::MTOCRF && MI.getOpcode() != PPC::MTOCRF8 &&
280            MI.getOpcode() != PPC::MFOCRF && MI.getOpcode() != PPC::MFOCRF8) ||
281           MO.getReg() < PPC::CR0 || MO.getReg() > PPC::CR7);
282    return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
283  }
284  
285  assert(MO.isImm() &&
286         "Relocation required in an instruction that we cannot encode!");
287  return MO.getImm();
288}
289
290#include "PPCGenCodeEmitter.inc"