MipsCodeEmitter.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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#include "Mips.h"
16#include "MCTargetDesc/MipsBaseInfo.h"
17#include "MipsInstrInfo.h"
18#include "MipsRelocations.h"
19#include "MipsSubtarget.h"
20#include "MipsTargetMachine.h"
21#include "llvm/ADT/Statistic.h"
22#include "llvm/CodeGen/JITCodeEmitter.h"
23#include "llvm/CodeGen/MachineConstantPool.h"
24#include "llvm/CodeGen/MachineFunctionPass.h"
25#include "llvm/CodeGen/MachineInstr.h"
26#include "llvm/CodeGen/MachineInstrBuilder.h"
27#include "llvm/CodeGen/MachineJumpTableInfo.h"
28#include "llvm/CodeGen/MachineModuleInfo.h"
29#include "llvm/CodeGen/MachineOperand.h"
30#include "llvm/CodeGen/Passes.h"
31#include "llvm/IR/Constants.h"
32#include "llvm/IR/DerivedTypes.h"
33#include "llvm/PassManager.h"
34#include "llvm/Support/Debug.h"
35#include "llvm/Support/ErrorHandling.h"
36#include "llvm/Support/raw_ostream.h"
37#ifndef NDEBUG
38#include <iomanip>
39#endif
40
41using namespace llvm;
42
43#define DEBUG_TYPE "jit"
44
45STATISTIC(NumEmitted, "Number of machine instructions emitted");
46
47namespace {
48
49class MipsCodeEmitter : public MachineFunctionPass {
50  MipsJITInfo *JTI;
51  const MipsInstrInfo *II;
52  const DataLayout *TD;
53  const MipsSubtarget *Subtarget;
54  TargetMachine &TM;
55  JITCodeEmitter &MCE;
56  const std::vector<MachineConstantPoolEntry> *MCPEs;
57  const std::vector<MachineJumpTableEntry> *MJTEs;
58  bool IsPIC;
59
60  void getAnalysisUsage(AnalysisUsage &AU) const override {
61    AU.addRequired<MachineModuleInfo> ();
62    MachineFunctionPass::getAnalysisUsage(AU);
63  }
64
65  static char ID;
66
67public:
68  MipsCodeEmitter(TargetMachine &tm, JITCodeEmitter &mce)
69    : MachineFunctionPass(ID), JTI(nullptr), II(nullptr), TD(nullptr),
70      TM(tm), MCE(mce), MCPEs(nullptr), MJTEs(nullptr),
71      IsPIC(TM.getRelocationModel() == Reloc::PIC_) {}
72
73  bool runOnMachineFunction(MachineFunction &MF) override;
74
75  const char *getPassName() const override {
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  unsigned getJumpTargetOpValueMM(const MachineInstr &MI, unsigned OpNo) const;
110  unsigned getBranchTargetOpValueMM(const MachineInstr &MI,
111                                    unsigned OpNo) const;
112
113  unsigned getBranchTarget21OpValue(const MachineInstr &MI,
114                                    unsigned OpNo) const;
115  unsigned getBranchTarget26OpValue(const MachineInstr &MI,
116                                    unsigned OpNo) const;
117  unsigned getJumpOffset16OpValue(const MachineInstr &MI, unsigned OpNo) const;
118
119  unsigned getBranchTargetOpValue(const MachineInstr &MI, unsigned OpNo) const;
120  unsigned getMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
121  unsigned getMemEncodingMMImm12(const MachineInstr &MI, unsigned OpNo) const;
122  unsigned getMSAMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
123  unsigned getSizeExtEncoding(const MachineInstr &MI, unsigned OpNo) const;
124  unsigned getSizeInsEncoding(const MachineInstr &MI, unsigned OpNo) const;
125  unsigned getLSAImmEncoding(const MachineInstr &MI, unsigned OpNo) const;
126  unsigned getSimm19Lsl2Encoding(const MachineInstr &MI, unsigned OpNo) const;
127
128  /// Expand pseudo instructions with accumulator register operands.
129  void expandACCInstr(MachineBasicBlock::instr_iterator MI,
130                      MachineBasicBlock &MBB, unsigned Opc) const;
131
132  /// \brief Expand pseudo instruction. Return true if MI was expanded.
133  bool expandPseudos(MachineBasicBlock::instr_iterator &MI,
134                     MachineBasicBlock &MBB) const;
135};
136}
137
138char MipsCodeEmitter::ID = 0;
139
140bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
141  MipsTargetMachine &Target = static_cast<MipsTargetMachine &>(
142                                const_cast<TargetMachine &>(MF.getTarget()));
143
144  JTI = Target.getJITInfo();
145  II = Target.getInstrInfo();
146  TD = Target.getDataLayout();
147  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
148  MCPEs = &MF.getConstantPool()->getConstants();
149  MJTEs = nullptr;
150  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
151  JTI->Initialize(MF, IsPIC, Subtarget->isLittle());
152  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
153
154  do {
155    DEBUG(errs() << "JITTing function '"
156        << MF.getName() << "'\n");
157    MCE.startFunction(MF);
158
159    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
160        MBB != E; ++MBB){
161      MCE.StartMachineBasicBlock(MBB);
162      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
163           E = MBB->instr_end(); I != E;)
164        emitInstruction(*I++, *MBB);
165    }
166  } while (MCE.finishFunction(MF));
167
168  return false;
169}
170
171unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
172                                        const MachineOperand &MO) const {
173  // NOTE: This relocations are for static.
174  uint64_t TSFlags = MI.getDesc().TSFlags;
175  uint64_t Form = TSFlags & MipsII::FormMask;
176  if (Form == MipsII::FrmJ)
177    return Mips::reloc_mips_26;
178  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
179       && MI.isBranch())
180    return Mips::reloc_mips_pc16;
181  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
182    return Mips::reloc_mips_hi;
183  return Mips::reloc_mips_lo;
184}
185
186unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
187                                               unsigned OpNo) const {
188  MachineOperand MO = MI.getOperand(OpNo);
189  if (MO.isGlobal())
190    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
191  else if (MO.isSymbol())
192    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
193  else if (MO.isMBB())
194    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
195  else
196    llvm_unreachable("Unexpected jump target operand kind.");
197  return 0;
198}
199
200unsigned MipsCodeEmitter::getJumpTargetOpValueMM(const MachineInstr &MI,
201                                                 unsigned OpNo) const {
202  llvm_unreachable("Unimplemented function.");
203  return 0;
204}
205
206unsigned MipsCodeEmitter::getBranchTargetOpValueMM(const MachineInstr &MI,
207                                                   unsigned OpNo) const {
208  llvm_unreachable("Unimplemented function.");
209  return 0;
210}
211
212unsigned MipsCodeEmitter::getBranchTarget21OpValue(const MachineInstr &MI,
213                                                   unsigned OpNo) const {
214  llvm_unreachable("Unimplemented function.");
215  return 0;
216}
217
218unsigned MipsCodeEmitter::getBranchTarget26OpValue(const MachineInstr &MI,
219                                                   unsigned OpNo) const {
220  llvm_unreachable("Unimplemented function.");
221  return 0;
222}
223
224unsigned MipsCodeEmitter::getJumpOffset16OpValue(const MachineInstr &MI,
225                                                 unsigned OpNo) const {
226  llvm_unreachable("Unimplemented function.");
227  return 0;
228}
229
230unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
231                                                 unsigned OpNo) const {
232  MachineOperand MO = MI.getOperand(OpNo);
233  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
234  return 0;
235}
236
237unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
238                                         unsigned OpNo) const {
239  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
240  assert(MI.getOperand(OpNo).isReg());
241  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
242  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
243}
244
245unsigned MipsCodeEmitter::getMemEncodingMMImm12(const MachineInstr &MI,
246                                                unsigned OpNo) const {
247  llvm_unreachable("Unimplemented function.");
248  return 0;
249}
250
251unsigned MipsCodeEmitter::getMSAMemEncoding(const MachineInstr &MI,
252                                            unsigned OpNo) const {
253  llvm_unreachable("Unimplemented function.");
254  return 0;
255}
256
257unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
258                                             unsigned OpNo) const {
259  // size is encoded as size-1.
260  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
261}
262
263unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
264                                             unsigned OpNo) const {
265  // size is encoded as pos+size-1.
266  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
267         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
268}
269
270unsigned MipsCodeEmitter::getLSAImmEncoding(const MachineInstr &MI,
271                                            unsigned OpNo) const {
272  llvm_unreachable("Unimplemented function.");
273  return 0;
274}
275
276unsigned MipsCodeEmitter::getSimm19Lsl2Encoding(const MachineInstr &MI,
277                                                unsigned OpNo) const {
278  llvm_unreachable("Unimplemented function.");
279  return 0;
280}
281
282/// getMachineOpValue - Return binary encoding of operand. If the machine
283/// operand requires relocation, record the relocation and return zero.
284unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
285                                            const MachineOperand &MO) const {
286  if (MO.isReg())
287    return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
288  else if (MO.isImm())
289    return static_cast<unsigned>(MO.getImm());
290  else if (MO.isGlobal())
291    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
292  else if (MO.isSymbol())
293    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
294  else if (MO.isCPI())
295    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
296  else if (MO.isJTI())
297    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
298  else if (MO.isMBB())
299    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
300  else
301    llvm_unreachable("Unable to encode MachineOperand!");
302  return 0;
303}
304
305void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
306                                        bool MayNeedFarStub) const {
307  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
308                                             const_cast<GlobalValue *>(GV), 0,
309                                             MayNeedFarStub));
310}
311
312void MipsCodeEmitter::
313emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
314  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
315                                                 Reloc, ES, 0, 0));
316}
317
318void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
319  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
320                                                    Reloc, CPI, 0, false));
321}
322
323void MipsCodeEmitter::
324emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
325  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
326                                                    Reloc, JTIndex, 0, false));
327}
328
329void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
330                                            unsigned Reloc) const {
331  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
332                                             Reloc, BB));
333}
334
335void MipsCodeEmitter::emitInstruction(MachineBasicBlock::instr_iterator MI,
336                                      MachineBasicBlock &MBB) {
337  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << *MI);
338
339  // Expand pseudo instruction. Skip if MI was not expanded.
340  if (((MI->getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo) &&
341      !expandPseudos(MI, MBB))
342    return;
343
344  MCE.processDebugLoc(MI->getDebugLoc(), true);
345
346  emitWord(getBinaryCodeForInstr(*MI));
347  ++NumEmitted;  // Keep track of the # of mi's emitted
348
349  MCE.processDebugLoc(MI->getDebugLoc(), false);
350}
351
352void MipsCodeEmitter::emitWord(unsigned Word) {
353  DEBUG(errs() << "  0x";
354        errs().write_hex(Word) << "\n");
355  if (Subtarget->isLittle())
356    MCE.emitWordLE(Word);
357  else
358    MCE.emitWordBE(Word);
359}
360
361void MipsCodeEmitter::expandACCInstr(MachineBasicBlock::instr_iterator MI,
362                                     MachineBasicBlock &MBB,
363                                     unsigned Opc) const {
364  // Expand "pseudomult $ac0, $t0, $t1" to "mult $t0, $t1".
365  BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Opc))
366    .addReg(MI->getOperand(1).getReg()).addReg(MI->getOperand(2).getReg());
367}
368
369bool MipsCodeEmitter::expandPseudos(MachineBasicBlock::instr_iterator &MI,
370                                    MachineBasicBlock &MBB) const {
371  switch (MI->getOpcode()) {
372  case Mips::NOP:
373    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::SLL), Mips::ZERO)
374      .addReg(Mips::ZERO).addImm(0);
375    break;
376  case Mips::B:
377    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::BEQ)).addReg(Mips::ZERO)
378      .addReg(Mips::ZERO).addOperand(MI->getOperand(0));
379    break;
380  case Mips::TRAP:
381    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::BREAK)).addImm(0)
382      .addImm(0);
383    break;
384  case Mips::JALRPseudo:
385    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::JALR), Mips::RA)
386      .addReg(MI->getOperand(0).getReg());
387    break;
388  case Mips::PseudoMULT:
389    expandACCInstr(MI, MBB, Mips::MULT);
390    break;
391  case Mips::PseudoMULTu:
392    expandACCInstr(MI, MBB, Mips::MULTu);
393    break;
394  case Mips::PseudoSDIV:
395    expandACCInstr(MI, MBB, Mips::SDIV);
396    break;
397  case Mips::PseudoUDIV:
398    expandACCInstr(MI, MBB, Mips::UDIV);
399    break;
400  case Mips::PseudoMADD:
401    expandACCInstr(MI, MBB, Mips::MADD);
402    break;
403  case Mips::PseudoMADDU:
404    expandACCInstr(MI, MBB, Mips::MADDU);
405    break;
406  case Mips::PseudoMSUB:
407    expandACCInstr(MI, MBB, Mips::MSUB);
408    break;
409  case Mips::PseudoMSUBU:
410    expandACCInstr(MI, MBB, Mips::MSUBU);
411    break;
412  default:
413    return false;
414  }
415
416  (MI--)->eraseFromBundle();
417  return true;
418}
419
420/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
421/// code to the specified MCE object.
422FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
423                                                 JITCodeEmitter &JCE) {
424  return new MipsCodeEmitter(TM, JCE);
425}
426
427#include "MipsGenCodeEmitter.inc"
428