MipsCodeEmitter.cpp revision 95adf91f29980e374bf094e15bc3f2764ef9baf4 
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), II(0), TD(0),
69      TM(tm), MCE(mce), MCPEs(0), MJTEs(0),
70      IsPIC(TM.getRelocationModel() == Reloc::PIC_) {}
71
72  bool runOnMachineFunction(MachineFunction &MF);
73
74  virtual const char *getPassName() const {
75    return "Mips Machine Code Emitter";
76  }
77
78  /// getBinaryCodeForInstr - This function, generated by the
79  /// CodeEmitterGenerator using TableGen, produces the binary encoding for
80  /// machine instructions.
81  uint64_t getBinaryCodeForInstr(const MachineInstr &MI) const;
82
83  void emitInstruction(MachineBasicBlock::instr_iterator MI,
84                       MachineBasicBlock &MBB);
85
86private:
87
88  void emitWord(unsigned Word);
89
90  /// Routines that handle operands which add machine relocations which are
91  /// fixed up by the relocation stage.
92  void emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
93                         bool MayNeedFarStub) const;
94  void emitExternalSymbolAddress(const char *ES, unsigned Reloc) const;
95  void emitConstPoolAddress(unsigned CPI, unsigned Reloc) const;
96  void emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const;
97  void emitMachineBasicBlock(MachineBasicBlock *BB, unsigned Reloc) const;
98
99  /// getMachineOpValue - Return binary encoding of operand. If the machine
100  /// operand requires relocation, record the relocation and return zero.
101  unsigned getMachineOpValue(const MachineInstr &MI,
102                             const MachineOperand &MO) const;
103
104  unsigned getRelocation(const MachineInstr &MI,
105                         const MachineOperand &MO) const;
106
107  unsigned getJumpTargetOpValue(const MachineInstr &MI, unsigned OpNo) const;
108  unsigned getJumpTargetOpValueMM(const MachineInstr &MI, unsigned OpNo) const;
109  unsigned getBranchTargetOpValueMM(const MachineInstr &MI,
110                                    unsigned OpNo) const;
111
112  unsigned getBranchTargetOpValue(const MachineInstr &MI, unsigned OpNo) const;
113  unsigned getMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
114  unsigned getMemEncodingMMImm12(const MachineInstr &MI, unsigned OpNo) const;
115  unsigned getSizeExtEncoding(const MachineInstr &MI, unsigned OpNo) const;
116  unsigned getSizeInsEncoding(const MachineInstr &MI, unsigned OpNo) const;
117  unsigned getLSAImmEncoding(const MachineInstr &MI, unsigned OpNo) const;
118
119  void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
120                                  int Offset) const;
121
122  /// Expand pseudo instructions with accumulator register operands.
123  void expandACCInstr(MachineBasicBlock::instr_iterator MI,
124                      MachineBasicBlock &MBB, unsigned Opc) const;
125
126  /// \brief Expand pseudo instruction. Return true if MI was expanded.
127  bool expandPseudos(MachineBasicBlock::instr_iterator &MI,
128                     MachineBasicBlock &MBB) const;
129};
130}
131
132char MipsCodeEmitter::ID = 0;
133
134bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
135  MipsTargetMachine &Target = static_cast<MipsTargetMachine &>(
136                                const_cast<TargetMachine &>(MF.getTarget()));
137
138  JTI = Target.getJITInfo();
139  II = Target.getInstrInfo();
140  TD = Target.getDataLayout();
141  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
142  MCPEs = &MF.getConstantPool()->getConstants();
143  MJTEs = 0;
144  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
145  JTI->Initialize(MF, IsPIC, Subtarget->isLittle());
146  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
147
148  do {
149    DEBUG(errs() << "JITTing function '"
150        << MF.getName() << "'\n");
151    MCE.startFunction(MF);
152
153    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
154        MBB != E; ++MBB){
155      MCE.StartMachineBasicBlock(MBB);
156      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
157           E = MBB->instr_end(); I != E;)
158        emitInstruction(*I++, *MBB);
159    }
160  } while (MCE.finishFunction(MF));
161
162  return false;
163}
164
165unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
166                                        const MachineOperand &MO) const {
167  // NOTE: This relocations are for static.
168  uint64_t TSFlags = MI.getDesc().TSFlags;
169  uint64_t Form = TSFlags & MipsII::FormMask;
170  if (Form == MipsII::FrmJ)
171    return Mips::reloc_mips_26;
172  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
173       && MI.isBranch())
174    return Mips::reloc_mips_pc16;
175  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
176    return Mips::reloc_mips_hi;
177  return Mips::reloc_mips_lo;
178}
179
180unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
181                                               unsigned OpNo) const {
182  MachineOperand MO = MI.getOperand(OpNo);
183  if (MO.isGlobal())
184    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
185  else if (MO.isSymbol())
186    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
187  else if (MO.isMBB())
188    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
189  else
190    llvm_unreachable("Unexpected jump target operand kind.");
191  return 0;
192}
193
194unsigned MipsCodeEmitter::getJumpTargetOpValueMM(const MachineInstr &MI,
195                                                 unsigned OpNo) const {
196  llvm_unreachable("Unimplemented function.");
197  return 0;
198}
199
200unsigned MipsCodeEmitter::getBranchTargetOpValueMM(const MachineInstr &MI,
201                                                   unsigned OpNo) const {
202  llvm_unreachable("Unimplemented function.");
203  return 0;
204}
205
206unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
207                                                 unsigned OpNo) const {
208  MachineOperand MO = MI.getOperand(OpNo);
209  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
210  return 0;
211}
212
213unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
214                                         unsigned OpNo) const {
215  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
216  assert(MI.getOperand(OpNo).isReg());
217  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
218  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
219}
220
221unsigned MipsCodeEmitter::getMemEncodingMMImm12(const MachineInstr &MI,
222                                                unsigned OpNo) const {
223  llvm_unreachable("Unimplemented function.");
224  return 0;
225}
226
227unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
228                                             unsigned OpNo) const {
229  // size is encoded as size-1.
230  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
231}
232
233unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
234                                             unsigned OpNo) const {
235  // size is encoded as pos+size-1.
236  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
237         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
238}
239
240unsigned MipsCodeEmitter::getLSAImmEncoding(const MachineInstr &MI,
241                                            unsigned OpNo) const {
242  llvm_unreachable("Unimplemented function.");
243  return 0;
244}
245
246/// getMachineOpValue - Return binary encoding of operand. If the machine
247/// operand requires relocation, record the relocation and return zero.
248unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
249                                            const MachineOperand &MO) const {
250  if (MO.isReg())
251    return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
252  else if (MO.isImm())
253    return static_cast<unsigned>(MO.getImm());
254  else if (MO.isGlobal())
255    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
256  else if (MO.isSymbol())
257    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
258  else if (MO.isCPI())
259    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
260  else if (MO.isJTI())
261    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
262  else if (MO.isMBB())
263    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
264  else
265    llvm_unreachable("Unable to encode MachineOperand!");
266  return 0;
267}
268
269void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
270                                        bool MayNeedFarStub) const {
271  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
272                                             const_cast<GlobalValue *>(GV), 0,
273                                             MayNeedFarStub));
274}
275
276void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
277                                           unsigned Reloc, int Offset) const {
278  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
279                             const_cast<GlobalValue *>(GV), 0, false));
280  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
281                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
282}
283
284void MipsCodeEmitter::
285emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
286  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
287                                                 Reloc, ES, 0, 0));
288}
289
290void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
291  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
292                                                    Reloc, CPI, 0, false));
293}
294
295void MipsCodeEmitter::
296emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
297  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
298                                                    Reloc, JTIndex, 0, false));
299}
300
301void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
302                                            unsigned Reloc) const {
303  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
304                                             Reloc, BB));
305}
306
307void MipsCodeEmitter::emitInstruction(MachineBasicBlock::instr_iterator MI,
308                                      MachineBasicBlock &MBB) {
309  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << *MI);
310
311  // Expand pseudo instruction. Skip if MI was not expanded.
312  if (((MI->getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo) &&
313      !expandPseudos(MI, MBB))
314    return;
315
316  MCE.processDebugLoc(MI->getDebugLoc(), true);
317
318  emitWord(getBinaryCodeForInstr(*MI));
319  ++NumEmitted;  // Keep track of the # of mi's emitted
320
321  MCE.processDebugLoc(MI->getDebugLoc(), false);
322}
323
324void MipsCodeEmitter::emitWord(unsigned Word) {
325  DEBUG(errs() << "  0x";
326        errs().write_hex(Word) << "\n");
327  if (Subtarget->isLittle())
328    MCE.emitWordLE(Word);
329  else
330    MCE.emitWordBE(Word);
331}
332
333void MipsCodeEmitter::expandACCInstr(MachineBasicBlock::instr_iterator MI,
334                                     MachineBasicBlock &MBB,
335                                     unsigned Opc) const {
336  // Expand "pseudomult $ac0, $t0, $t1" to "mult $t0, $t1".
337  BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Opc))
338    .addReg(MI->getOperand(1).getReg()).addReg(MI->getOperand(2).getReg());
339}
340
341bool MipsCodeEmitter::expandPseudos(MachineBasicBlock::instr_iterator &MI,
342                                    MachineBasicBlock &MBB) const {
343  switch (MI->getOpcode()) {
344  case Mips::NOP:
345    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::SLL), Mips::ZERO)
346      .addReg(Mips::ZERO).addImm(0);
347    break;
348  case Mips::B:
349    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::BEQ)).addReg(Mips::ZERO)
350      .addReg(Mips::ZERO).addOperand(MI->getOperand(0));
351    break;
352  case Mips::TRAP:
353    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::BREAK)).addImm(0)
354      .addImm(0);
355    break;
356  case Mips::JALRPseudo:
357    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::JALR), Mips::RA)
358      .addReg(MI->getOperand(0).getReg());
359    break;
360  case Mips::PseudoMULT:
361    expandACCInstr(MI, MBB, Mips::MULT);
362    break;
363  case Mips::PseudoMULTu:
364    expandACCInstr(MI, MBB, Mips::MULTu);
365    break;
366  case Mips::PseudoSDIV:
367    expandACCInstr(MI, MBB, Mips::SDIV);
368    break;
369  case Mips::PseudoUDIV:
370    expandACCInstr(MI, MBB, Mips::UDIV);
371    break;
372  case Mips::PseudoMADD:
373    expandACCInstr(MI, MBB, Mips::MADD);
374    break;
375  case Mips::PseudoMADDU:
376    expandACCInstr(MI, MBB, Mips::MADDU);
377    break;
378  case Mips::PseudoMSUB:
379    expandACCInstr(MI, MBB, Mips::MSUB);
380    break;
381  case Mips::PseudoMSUBU:
382    expandACCInstr(MI, MBB, Mips::MSUBU);
383    break;
384  default:
385    return false;
386  }
387
388  (MI--)->eraseFromBundle();
389  return true;
390}
391
392/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
393/// code to the specified MCE object.
394FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
395                                                 JITCodeEmitter &JCE) {
396  return new MipsCodeEmitter(TM, JCE);
397}
398
399#include "MipsGenCodeEmitter.inc"
400