MipsCodeEmitter.cpp revision fee62c167b1f731998ff4d315830154d17ec6f85 
1//===-- Mips/MipsCodeEmitter.cpp - Convert Mips Code to Machine Code ------===//
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 contains the pass that transforms the Mips machine instructions
11// into relocatable machine code.
12//
13//===---------------------------------------------------------------------===//
14
15#define DEBUG_TYPE "jit"
16#include "Mips.h"
17#include "MCTargetDesc/MipsBaseInfo.h"
18#include "MipsInstrInfo.h"
19#include "MipsRelocations.h"
20#include "MipsSubtarget.h"
21#include "MipsTargetMachine.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/CodeGen/JITCodeEmitter.h"
24#include "llvm/CodeGen/MachineConstantPool.h"
25#include "llvm/CodeGen/MachineFunctionPass.h"
26#include "llvm/CodeGen/MachineInstr.h"
27#include "llvm/CodeGen/MachineJumpTableInfo.h"
28#include "llvm/CodeGen/MachineInstrBuilder.h"
29#include "llvm/CodeGen/MachineModuleInfo.h"
30#include "llvm/CodeGen/MachineOperand.h"
31#include "llvm/CodeGen/Passes.h"
32#include "llvm/IR/Constants.h"
33#include "llvm/IR/DerivedTypes.h"
34#include "llvm/PassManager.h"
35#include "llvm/Support/Debug.h"
36#include "llvm/Support/ErrorHandling.h"
37#include "llvm/Support/raw_ostream.h"
38#ifndef NDEBUG
39#include <iomanip>
40#endif
41
42using namespace llvm;
43
44STATISTIC(NumEmitted, "Number of machine instructions emitted");
45
46namespace {
47
48class MipsCodeEmitter : public MachineFunctionPass {
49  MipsJITInfo *JTI;
50  const MipsInstrInfo *II;
51  const DataLayout *TD;
52  const MipsSubtarget *Subtarget;
53  TargetMachine &TM;
54  JITCodeEmitter &MCE;
55  const std::vector<MachineConstantPoolEntry> *MCPEs;
56  const std::vector<MachineJumpTableEntry> *MJTEs;
57  bool IsPIC;
58
59  void getAnalysisUsage(AnalysisUsage &AU) const {
60    AU.addRequired<MachineModuleInfo> ();
61    MachineFunctionPass::getAnalysisUsage(AU);
62  }
63
64  static char ID;
65
66public:
67  MipsCodeEmitter(TargetMachine &tm, JITCodeEmitter &mce)
68    : MachineFunctionPass(ID), JTI(0),
69      II((const MipsInstrInfo *) tm.getInstrInfo()), TD(tm.getDataLayout()),
70      TM(tm), MCE(mce), MCPEs(0), MJTEs(0),
71      IsPIC(TM.getRelocationModel() == Reloc::PIC_) {}
72
73  bool runOnMachineFunction(MachineFunction &MF);
74
75  virtual const char *getPassName() const {
76    return "Mips Machine Code Emitter";
77  }
78
79  /// getBinaryCodeForInstr - This function, generated by the
80  /// CodeEmitterGenerator using TableGen, produces the binary encoding for
81  /// machine instructions.
82  uint64_t getBinaryCodeForInstr(const MachineInstr &MI) const;
83
84  void emitInstruction(MachineBasicBlock::instr_iterator MI,
85                       MachineBasicBlock &MBB);
86
87private:
88
89  void emitWord(unsigned Word);
90
91  /// Routines that handle operands which add machine relocations which are
92  /// fixed up by the relocation stage.
93  void emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
94                         bool MayNeedFarStub) const;
95  void emitExternalSymbolAddress(const char *ES, unsigned Reloc) const;
96  void emitConstPoolAddress(unsigned CPI, unsigned Reloc) const;
97  void emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const;
98  void emitMachineBasicBlock(MachineBasicBlock *BB, unsigned Reloc) const;
99
100  /// getMachineOpValue - Return binary encoding of operand. If the machine
101  /// operand requires relocation, record the relocation and return zero.
102  unsigned getMachineOpValue(const MachineInstr &MI,
103                             const MachineOperand &MO) const;
104
105  unsigned getRelocation(const MachineInstr &MI,
106                         const MachineOperand &MO) const;
107
108  unsigned getJumpTargetOpValue(const MachineInstr &MI, unsigned OpNo) const;
109
110  unsigned getBranchTargetOpValue(const MachineInstr &MI, unsigned OpNo) const;
111  unsigned getMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
112  unsigned getSizeExtEncoding(const MachineInstr &MI, unsigned OpNo) const;
113  unsigned getSizeInsEncoding(const MachineInstr &MI, unsigned OpNo) const;
114
115  void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
116                                  int Offset) const;
117
118  /// Expand pseudo instructions with accumulator register operands.
119  void expandACCInstr(MachineBasicBlock::instr_iterator MI,
120                      MachineBasicBlock &MBB, unsigned Opc) const;
121
122  /// \brief Expand pseudo instruction. Return true if MI was expanded.
123  bool expandPseudos(MachineBasicBlock::instr_iterator &MI,
124                     MachineBasicBlock &MBB) const;
125};
126}
127
128char MipsCodeEmitter::ID = 0;
129
130bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
131  MipsTargetMachine &Target = static_cast<MipsTargetMachine &>(
132                                const_cast<TargetMachine &>(MF.getTarget()));
133
134  JTI = Target.getJITInfo();
135  II = Target.getInstrInfo();
136  TD = Target.getDataLayout();
137  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
138  MCPEs = &MF.getConstantPool()->getConstants();
139  MJTEs = 0;
140  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
141  JTI->Initialize(MF, IsPIC, Subtarget->isLittle());
142  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
143
144  do {
145    DEBUG(errs() << "JITTing function '"
146        << MF.getName() << "'\n");
147    MCE.startFunction(MF);
148
149    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
150        MBB != E; ++MBB){
151      MCE.StartMachineBasicBlock(MBB);
152      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
153           E = MBB->instr_end(); I != E;)
154        emitInstruction(*I++, *MBB);
155    }
156  } while (MCE.finishFunction(MF));
157
158  return false;
159}
160
161unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
162                                        const MachineOperand &MO) const {
163  // NOTE: This relocations are for static.
164  uint64_t TSFlags = MI.getDesc().TSFlags;
165  uint64_t Form = TSFlags & MipsII::FormMask;
166  if (Form == MipsII::FrmJ)
167    return Mips::reloc_mips_26;
168  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
169       && MI.isBranch())
170    return Mips::reloc_mips_pc16;
171  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
172    return Mips::reloc_mips_hi;
173  return Mips::reloc_mips_lo;
174}
175
176unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
177                                               unsigned OpNo) const {
178  MachineOperand MO = MI.getOperand(OpNo);
179  if (MO.isGlobal())
180    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
181  else if (MO.isSymbol())
182    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
183  else if (MO.isMBB())
184    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
185  else
186    llvm_unreachable("Unexpected jump target operand kind.");
187  return 0;
188}
189
190unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
191                                                 unsigned OpNo) const {
192  MachineOperand MO = MI.getOperand(OpNo);
193  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
194  return 0;
195}
196
197unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
198                                         unsigned OpNo) const {
199  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
200  assert(MI.getOperand(OpNo).isReg());
201  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
202  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
203}
204
205unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
206                                             unsigned OpNo) const {
207  // size is encoded as size-1.
208  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
209}
210
211unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
212                                             unsigned OpNo) const {
213  // size is encoded as pos+size-1.
214  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
215         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
216}
217
218/// getMachineOpValue - Return binary encoding of operand. If the machine
219/// operand requires relocation, record the relocation and return zero.
220unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
221                                            const MachineOperand &MO) const {
222  if (MO.isReg())
223    return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
224  else if (MO.isImm())
225    return static_cast<unsigned>(MO.getImm());
226  else if (MO.isGlobal())
227    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
228  else if (MO.isSymbol())
229    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
230  else if (MO.isCPI())
231    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
232  else if (MO.isJTI())
233    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
234  else if (MO.isMBB())
235    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
236  else
237    llvm_unreachable("Unable to encode MachineOperand!");
238  return 0;
239}
240
241void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
242                                        bool MayNeedFarStub) const {
243  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
244                                             const_cast<GlobalValue *>(GV), 0,
245                                             MayNeedFarStub));
246}
247
248void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
249                                           unsigned Reloc, int Offset) const {
250  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
251                             const_cast<GlobalValue *>(GV), 0, false));
252  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
253                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
254}
255
256void MipsCodeEmitter::
257emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
258  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
259                                                 Reloc, ES, 0, 0));
260}
261
262void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
263  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
264                                                    Reloc, CPI, 0, false));
265}
266
267void MipsCodeEmitter::
268emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
269  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
270                                                    Reloc, JTIndex, 0, false));
271}
272
273void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
274                                            unsigned Reloc) const {
275  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
276                                             Reloc, BB));
277}
278
279void MipsCodeEmitter::emitInstruction(MachineBasicBlock::instr_iterator MI,
280                                      MachineBasicBlock &MBB) {
281  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << *MI);
282
283  // Expand pseudo instruction. Skip if MI was not expanded.
284  if (((MI->getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo) &&
285      !expandPseudos(MI, MBB))
286    return;
287
288  MCE.processDebugLoc(MI->getDebugLoc(), true);
289
290  emitWord(getBinaryCodeForInstr(*MI));
291  ++NumEmitted;  // Keep track of the # of mi's emitted
292
293  MCE.processDebugLoc(MI->getDebugLoc(), false);
294}
295
296void MipsCodeEmitter::emitWord(unsigned Word) {
297  DEBUG(errs() << "  0x";
298        errs().write_hex(Word) << "\n");
299  if (Subtarget->isLittle())
300    MCE.emitWordLE(Word);
301  else
302    MCE.emitWordBE(Word);
303}
304
305void MipsCodeEmitter::expandACCInstr(MachineBasicBlock::instr_iterator MI,
306                                     MachineBasicBlock &MBB,
307                                     unsigned Opc) const {
308  // Expand "pseudomult $ac0, $t0, $t1" to "mult $t0, $t1".
309  BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Opc))
310    .addReg(MI->getOperand(1).getReg()).addReg(MI->getOperand(2).getReg());
311}
312
313bool MipsCodeEmitter::expandPseudos(MachineBasicBlock::instr_iterator &MI,
314                                    MachineBasicBlock &MBB) const {
315  switch (MI->getOpcode()) {
316  case Mips::NOP:
317    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::SLL), Mips::ZERO)
318      .addReg(Mips::ZERO).addImm(0);
319    break;
320  case Mips::JALRPseudo:
321    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::JALR), Mips::RA)
322      .addReg(MI->getOperand(0).getReg());
323    break;
324  case Mips::PseudoMULT:
325    expandACCInstr(MI, MBB, Mips::MULT);
326    break;
327  case Mips::PseudoMULTu:
328    expandACCInstr(MI, MBB, Mips::MULTu);
329    break;
330  case Mips::PseudoSDIV:
331    expandACCInstr(MI, MBB, Mips::SDIV);
332    break;
333  case Mips::PseudoUDIV:
334    expandACCInstr(MI, MBB, Mips::UDIV);
335    break;
336  case Mips::PseudoMADD:
337    expandACCInstr(MI, MBB, Mips::MADD);
338    break;
339  case Mips::PseudoMADDU:
340    expandACCInstr(MI, MBB, Mips::MADDU);
341    break;
342  case Mips::PseudoMSUB:
343    expandACCInstr(MI, MBB, Mips::MSUB);
344    break;
345  case Mips::PseudoMSUBU:
346    expandACCInstr(MI, MBB, Mips::MSUBU);
347    break;
348  default:
349    return false;
350  }
351
352  (MI--)->eraseFromBundle();
353  return true;
354}
355
356/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
357/// code to the specified MCE object.
358FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
359                                                 JITCodeEmitter &JCE) {
360  return new MipsCodeEmitter(TM, JCE);
361}
362
363#include "MipsGenCodeEmitter.inc"
364