MipsCodeEmitter.cpp revision 41e632d9e1a55d36cb08b0551ad82a13d9137a5e 
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
109  unsigned getBranchTargetOpValue(const MachineInstr &MI, unsigned OpNo) const;
110  unsigned getMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
111  unsigned getSizeExtEncoding(const MachineInstr &MI, unsigned OpNo) const;
112  unsigned getSizeInsEncoding(const MachineInstr &MI, unsigned OpNo) const;
113
114  void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
115                                  int Offset) const;
116
117  /// Expand pseudo instructions with accumulator register operands.
118  void expandACCInstr(MachineBasicBlock::instr_iterator MI,
119                      MachineBasicBlock &MBB, unsigned Opc) const;
120
121  /// \brief Expand pseudo instruction. Return true if MI was expanded.
122  bool expandPseudos(MachineBasicBlock::instr_iterator &MI,
123                     MachineBasicBlock &MBB) const;
124};
125}
126
127char MipsCodeEmitter::ID = 0;
128
129bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
130  MipsTargetMachine &Target = static_cast<MipsTargetMachine &>(
131                                const_cast<TargetMachine &>(MF.getTarget()));
132
133  JTI = Target.getJITInfo();
134  II = Target.getInstrInfo();
135  TD = Target.getDataLayout();
136  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
137  MCPEs = &MF.getConstantPool()->getConstants();
138  MJTEs = 0;
139  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
140  JTI->Initialize(MF, IsPIC, Subtarget->isLittle());
141  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
142
143  do {
144    DEBUG(errs() << "JITTing function '"
145        << MF.getName() << "'\n");
146    MCE.startFunction(MF);
147
148    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
149        MBB != E; ++MBB){
150      MCE.StartMachineBasicBlock(MBB);
151      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
152           E = MBB->instr_end(); I != E;)
153        emitInstruction(*I++, *MBB);
154    }
155  } while (MCE.finishFunction(MF));
156
157  return false;
158}
159
160unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
161                                        const MachineOperand &MO) const {
162  // NOTE: This relocations are for static.
163  uint64_t TSFlags = MI.getDesc().TSFlags;
164  uint64_t Form = TSFlags & MipsII::FormMask;
165  if (Form == MipsII::FrmJ)
166    return Mips::reloc_mips_26;
167  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
168       && MI.isBranch())
169    return Mips::reloc_mips_pc16;
170  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
171    return Mips::reloc_mips_hi;
172  return Mips::reloc_mips_lo;
173}
174
175unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
176                                               unsigned OpNo) const {
177  MachineOperand MO = MI.getOperand(OpNo);
178  if (MO.isGlobal())
179    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
180  else if (MO.isSymbol())
181    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
182  else if (MO.isMBB())
183    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
184  else
185    llvm_unreachable("Unexpected jump target operand kind.");
186  return 0;
187}
188
189unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
190                                                 unsigned OpNo) const {
191  MachineOperand MO = MI.getOperand(OpNo);
192  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
193  return 0;
194}
195
196unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
197                                         unsigned OpNo) const {
198  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
199  assert(MI.getOperand(OpNo).isReg());
200  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
201  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
202}
203
204unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
205                                             unsigned OpNo) const {
206  // size is encoded as size-1.
207  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
208}
209
210unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
211                                             unsigned OpNo) const {
212  // size is encoded as pos+size-1.
213  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
214         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
215}
216
217/// getMachineOpValue - Return binary encoding of operand. If the machine
218/// operand requires relocation, record the relocation and return zero.
219unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
220                                            const MachineOperand &MO) const {
221  if (MO.isReg())
222    return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
223  else if (MO.isImm())
224    return static_cast<unsigned>(MO.getImm());
225  else if (MO.isGlobal())
226    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
227  else if (MO.isSymbol())
228    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
229  else if (MO.isCPI())
230    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
231  else if (MO.isJTI())
232    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
233  else if (MO.isMBB())
234    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
235  else
236    llvm_unreachable("Unable to encode MachineOperand!");
237  return 0;
238}
239
240void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
241                                        bool MayNeedFarStub) const {
242  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
243                                             const_cast<GlobalValue *>(GV), 0,
244                                             MayNeedFarStub));
245}
246
247void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
248                                           unsigned Reloc, int Offset) const {
249  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
250                             const_cast<GlobalValue *>(GV), 0, false));
251  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
252                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
253}
254
255void MipsCodeEmitter::
256emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
257  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
258                                                 Reloc, ES, 0, 0));
259}
260
261void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
262  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
263                                                    Reloc, CPI, 0, false));
264}
265
266void MipsCodeEmitter::
267emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
268  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
269                                                    Reloc, JTIndex, 0, false));
270}
271
272void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
273                                            unsigned Reloc) const {
274  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
275                                             Reloc, BB));
276}
277
278void MipsCodeEmitter::emitInstruction(MachineBasicBlock::instr_iterator MI,
279                                      MachineBasicBlock &MBB) {
280  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << *MI);
281
282  // Expand pseudo instruction. Skip if MI was not expanded.
283  if (((MI->getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo) &&
284      !expandPseudos(MI, MBB))
285    return;
286
287  MCE.processDebugLoc(MI->getDebugLoc(), true);
288
289  emitWord(getBinaryCodeForInstr(*MI));
290  ++NumEmitted;  // Keep track of the # of mi's emitted
291
292  MCE.processDebugLoc(MI->getDebugLoc(), false);
293}
294
295void MipsCodeEmitter::emitWord(unsigned Word) {
296  DEBUG(errs() << "  0x";
297        errs().write_hex(Word) << "\n");
298  if (Subtarget->isLittle())
299    MCE.emitWordLE(Word);
300  else
301    MCE.emitWordBE(Word);
302}
303
304void MipsCodeEmitter::expandACCInstr(MachineBasicBlock::instr_iterator MI,
305                                     MachineBasicBlock &MBB,
306                                     unsigned Opc) const {
307  // Expand "pseudomult $ac0, $t0, $t1" to "mult $t0, $t1".
308  BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Opc))
309    .addReg(MI->getOperand(1).getReg()).addReg(MI->getOperand(2).getReg());
310}
311
312bool MipsCodeEmitter::expandPseudos(MachineBasicBlock::instr_iterator &MI,
313                                    MachineBasicBlock &MBB) const {
314  switch (MI->getOpcode()) {
315  case Mips::NOP:
316    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::SLL), Mips::ZERO)
317      .addReg(Mips::ZERO).addImm(0);
318    break;
319  case Mips::JALRPseudo:
320    BuildMI(MBB, &*MI, MI->getDebugLoc(), II->get(Mips::JALR), Mips::RA)
321      .addReg(MI->getOperand(0).getReg());
322    break;
323  case Mips::PseudoMULT:
324    expandACCInstr(MI, MBB, Mips::MULT);
325    break;
326  case Mips::PseudoMULTu:
327    expandACCInstr(MI, MBB, Mips::MULTu);
328    break;
329  case Mips::PseudoSDIV:
330    expandACCInstr(MI, MBB, Mips::SDIV);
331    break;
332  case Mips::PseudoUDIV:
333    expandACCInstr(MI, MBB, Mips::UDIV);
334    break;
335  case Mips::PseudoMADD:
336    expandACCInstr(MI, MBB, Mips::MADD);
337    break;
338  case Mips::PseudoMADDU:
339    expandACCInstr(MI, MBB, Mips::MADDU);
340    break;
341  case Mips::PseudoMSUB:
342    expandACCInstr(MI, MBB, Mips::MSUB);
343    break;
344  case Mips::PseudoMSUBU:
345    expandACCInstr(MI, MBB, Mips::MSUBU);
346    break;
347  default:
348    return false;
349  }
350
351  (MI--)->eraseFromBundle();
352  return true;
353}
354
355/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
356/// code to the specified MCE object.
357FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
358                                                 JITCodeEmitter &JCE) {
359  return new MipsCodeEmitter(TM, JCE);
360}
361
362#include "MipsGenCodeEmitter.inc"
363