MipsCodeEmitter.cpp revision 5c042162beb3c2dd556e00aab84c4278a69cd5b1 
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
118  void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
119                                  int Offset) const;
120
121  /// Expand pseudo instructions with accumulator register operands.
122  void expandACCInstr(MachineBasicBlock::instr_iterator MI,
123                      MachineBasicBlock &MBB, unsigned Opc) const;
124
125  /// \brief Expand pseudo instruction. Return true if MI was expanded.
126  bool expandPseudos(MachineBasicBlock::instr_iterator &MI,
127                     MachineBasicBlock &MBB) const;
128};
129}
130
131char MipsCodeEmitter::ID = 0;
132
133bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
134  MipsTargetMachine &Target = static_cast<MipsTargetMachine &>(
135                                const_cast<TargetMachine &>(MF.getTarget()));
136
137  JTI = Target.getJITInfo();
138  II = Target.getInstrInfo();
139  TD = Target.getDataLayout();
140  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
141  MCPEs = &MF.getConstantPool()->getConstants();
142  MJTEs = 0;
143  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
144  JTI->Initialize(MF, IsPIC, Subtarget->isLittle());
145  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
146
147  do {
148    DEBUG(errs() << "JITTing function '"
149        << MF.getName() << "'\n");
150    MCE.startFunction(MF);
151
152    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
153        MBB != E; ++MBB){
154      MCE.StartMachineBasicBlock(MBB);
155      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
156           E = MBB->instr_end(); I != E;)
157        emitInstruction(*I++, *MBB);
158    }
159  } while (MCE.finishFunction(MF));
160
161  return false;
162}
163
164unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
165                                        const MachineOperand &MO) const {
166  // NOTE: This relocations are for static.
167  uint64_t TSFlags = MI.getDesc().TSFlags;
168  uint64_t Form = TSFlags & MipsII::FormMask;
169  if (Form == MipsII::FrmJ)
170    return Mips::reloc_mips_26;
171  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
172       && MI.isBranch())
173    return Mips::reloc_mips_pc16;
174  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
175    return Mips::reloc_mips_hi;
176  return Mips::reloc_mips_lo;
177}
178
179unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
180                                               unsigned OpNo) const {
181  MachineOperand MO = MI.getOperand(OpNo);
182  if (MO.isGlobal())
183    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
184  else if (MO.isSymbol())
185    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
186  else if (MO.isMBB())
187    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
188  else
189    llvm_unreachable("Unexpected jump target operand kind.");
190  return 0;
191}
192
193unsigned MipsCodeEmitter::getJumpTargetOpValueMM(const MachineInstr &MI,
194                                                 unsigned OpNo) const {
195  llvm_unreachable("Unimplemented function.");
196  return 0;
197}
198
199unsigned MipsCodeEmitter::getBranchTargetOpValueMM(const MachineInstr &MI,
200                                                   unsigned OpNo) const {
201  llvm_unreachable("Unimplemented function.");
202  return 0;
203}
204
205unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
206                                                 unsigned OpNo) const {
207  MachineOperand MO = MI.getOperand(OpNo);
208  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
209  return 0;
210}
211
212unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
213                                         unsigned OpNo) const {
214  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
215  assert(MI.getOperand(OpNo).isReg());
216  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
217  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
218}
219
220unsigned MipsCodeEmitter::getMemEncodingMMImm12(const MachineInstr &MI,
221                                                unsigned OpNo) const {
222  llvm_unreachable("Unimplemented function.");
223  return 0;
224}
225
226unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
227                                             unsigned OpNo) const {
228  // size is encoded as size-1.
229  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
230}
231
232unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
233                                             unsigned OpNo) const {
234  // size is encoded as pos+size-1.
235  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
236         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
237}
238
239/// getMachineOpValue - Return binary encoding of operand. If the machine
240/// operand requires relocation, record the relocation and return zero.
241unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
242                                            const MachineOperand &MO) const {
243  if (MO.isReg())
244    return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
245  else if (MO.isImm())
246    return static_cast<unsigned>(MO.getImm());
247  else if (MO.isGlobal())
248    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
249  else if (MO.isSymbol())
250    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
251  else if (MO.isCPI())
252    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
253  else if (MO.isJTI())
254    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
255  else if (MO.isMBB())
256    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
257  else
258    llvm_unreachable("Unable to encode MachineOperand!");
259  return 0;
260}
261
262void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
263                                        bool MayNeedFarStub) const {
264  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
265                                             const_cast<GlobalValue *>(GV), 0,
266                                             MayNeedFarStub));
267}
268
269void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
270                                           unsigned Reloc, int Offset) const {
271  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
272                             const_cast<GlobalValue *>(GV), 0, false));
273  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
274                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
275}
276
277void MipsCodeEmitter::
278emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
279  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
280                                                 Reloc, ES, 0, 0));
281}
282
283void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
284  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
285                                                    Reloc, CPI, 0, false));
286}
287
288void MipsCodeEmitter::
289emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
290  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
291                                                    Reloc, JTIndex, 0, false));
292}
293
294void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
295                                            unsigned Reloc) const {
296  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
297                                             Reloc, BB));
298}
299
300void MipsCodeEmitter::emitInstruction(MachineBasicBlock::instr_iterator MI,
301                                      MachineBasicBlock &MBB) {
302  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << *MI);
303
304  // Expand pseudo instruction. Skip if MI was not expanded.
305  if (((MI->getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo) &&
306      !expandPseudos(MI, MBB))
307    return;
308
309  MCE.processDebugLoc(MI->getDebugLoc(), true);
310
311  emitWord(getBinaryCodeForInstr(*MI));
312  ++NumEmitted;  // Keep track of the # of mi's emitted
313
314  MCE.processDebugLoc(MI->getDebugLoc(), false);
315}
316
317void MipsCodeEmitter::emitWord(unsigned Word) {
318  DEBUG(errs() << "  0x";
319        errs().write_hex(Word) << "\n");
320  if (Subtarget->isLittle())
321    MCE.emitWordLE(Word);
322  else
323    MCE.emitWordBE(Word);
324}
325
326void MipsCodeEmitter::expandACCInstr(MachineBasicBlock::instr_iterator MI,
327                                     MachineBasicBlock &MBB,
328                                     unsigned Opc) const {
329  // Expand "pseudomult $ac0, $t0, $t1" to "mult $t0, $t1".
330  BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Opc))
331    .addReg(MI->getOperand(1).getReg()).addReg(MI->getOperand(2).getReg());
332}
333
334bool MipsCodeEmitter::expandPseudos(MachineBasicBlock::instr_iterator &MI,
335                                    MachineBasicBlock &MBB) const {
336  switch (MI->getOpcode()) {
337  case Mips::NOP:
338    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::SLL), Mips::ZERO)
339      .addReg(Mips::ZERO).addImm(0);
340    break;
341  case Mips::B:
342    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::BEQ)).addReg(Mips::ZERO)
343      .addReg(Mips::ZERO).addOperand(MI->getOperand(0));
344    break;
345  case Mips::TRAP:
346    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::BREAK)).addImm(0)
347      .addImm(0);
348    break;
349  case Mips::JALRPseudo:
350    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::JALR), Mips::RA)
351      .addReg(MI->getOperand(0).getReg());
352    break;
353  case Mips::PseudoMULT:
354    expandACCInstr(MI, MBB, Mips::MULT);
355    break;
356  case Mips::PseudoMULTu:
357    expandACCInstr(MI, MBB, Mips::MULTu);
358    break;
359  case Mips::PseudoSDIV:
360    expandACCInstr(MI, MBB, Mips::SDIV);
361    break;
362  case Mips::PseudoUDIV:
363    expandACCInstr(MI, MBB, Mips::UDIV);
364    break;
365  case Mips::PseudoMADD:
366    expandACCInstr(MI, MBB, Mips::MADD);
367    break;
368  case Mips::PseudoMADDU:
369    expandACCInstr(MI, MBB, Mips::MADDU);
370    break;
371  case Mips::PseudoMSUB:
372    expandACCInstr(MI, MBB, Mips::MSUB);
373    break;
374  case Mips::PseudoMSUBU:
375    expandACCInstr(MI, MBB, Mips::MSUBU);
376    break;
377  default:
378    return false;
379  }
380
381  (MI--)->eraseFromBundle();
382  return true;
383}
384
385/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
386/// code to the specified MCE object.
387FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
388                                                 JITCodeEmitter &JCE) {
389  return new MipsCodeEmitter(TM, JCE);
390}
391
392#include "MipsGenCodeEmitter.inc"
393