MipsCodeEmitter.cpp revision 8f5e8c1cd69fa77bea20140a7132ee2dea166c6d 
1//== Mips/MipsCodeEmitter.cpp - Convert Mips Code to Machine Code -*- C++ -*-=//
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 "MipsInstrInfo.h"
18#include "MipsRelocations.h"
19#include "MipsSubtarget.h"
20#include "MipsTargetMachine.h"
21#include "MCTargetDesc/MipsBaseInfo.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/MachineModuleInfo.h"
29#include "llvm/CodeGen/MachineOperand.h"
30#include "llvm/CodeGen/Passes.h"
31#include "llvm/Constants.h"
32#include "llvm/DerivedTypes.h"
33#include "llvm/Function.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 TargetData *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
66  public:
67    MipsCodeEmitter(TargetMachine &tm, JITCodeEmitter &mce) :
68      MachineFunctionPass(ID), JTI(0),
69      II((const MipsInstrInfo *) tm.getInstrInfo()),
70      TD(tm.getTargetData()), TM(tm), MCE(mce), MCPEs(0), MJTEs(0),
71      IsPIC(TM.getRelocationModel() == Reloc::PIC_) {
72    }
73
74    bool runOnMachineFunction(MachineFunction &MF);
75
76    virtual const char *getPassName() const {
77      return "Mips Machine Code Emitter";
78    }
79
80    /// getBinaryCodeForInstr - This function, generated by the
81    /// CodeEmitterGenerator using TableGen, produces the binary encoding for
82    /// machine instructions.
83    uint64_t getBinaryCodeForInstr(const MachineInstr &MI) const;
84
85    void emitInstruction(const MachineInstr &MI);
86
87  private:
88
89    void emitWordLE(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,
111                                    unsigned OpNo) const;
112    unsigned getMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
113    unsigned getSizeExtEncoding(const MachineInstr &MI, unsigned OpNo) const;
114    unsigned getSizeInsEncoding(const MachineInstr &MI, unsigned OpNo) const;
115
116    int emitULW(const MachineInstr &MI);
117    int emitUSW(const MachineInstr &MI);
118    int emitULH(const MachineInstr &MI);
119    int emitULHu(const MachineInstr &MI);
120    int emitUSH(const MachineInstr &MI);
121
122    void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
123                                    int Offset) const;
124  };
125}
126
127char MipsCodeEmitter::ID = 0;
128
129bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
130  JTI = ((MipsTargetMachine&) MF.getTarget()).getJITInfo();
131  II = ((const MipsTargetMachine&) MF.getTarget()).getInstrInfo();
132  TD = ((const MipsTargetMachine&) MF.getTarget()).getTargetData();
133  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
134  MCPEs = &MF.getConstantPool()->getConstants();
135  MJTEs = 0;
136  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
137  JTI->Initialize(MF, IsPIC);
138  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
139
140  do {
141    DEBUG(errs() << "JITTing function '"
142        << MF.getFunction()->getName() << "'\n");
143    MCE.startFunction(MF);
144
145    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
146        MBB != E; ++MBB){
147      MCE.StartMachineBasicBlock(MBB);
148      for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
149          I != E; ++I)
150        emitInstruction(*I);
151    }
152  } while (MCE.finishFunction(MF));
153
154  return false;
155}
156
157unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
158                                        const MachineOperand &MO) const {
159  // NOTE: This relocations are for static.
160  uint64_t TSFlags = MI.getDesc().TSFlags;
161  uint64_t Form = TSFlags & MipsII::FormMask;
162  if (Form == MipsII::FrmJ)
163    return Mips::reloc_mips_26;
164  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
165       && MI.isBranch())
166    return Mips::reloc_mips_pc16;
167  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
168    return Mips::reloc_mips_hi;
169  return Mips::reloc_mips_lo;
170}
171
172unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
173                                               unsigned OpNo) const {
174  MachineOperand MO = MI.getOperand(OpNo);
175  if (MO.isGlobal())
176    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
177  else if (MO.isSymbol())
178    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
179  else if (MO.isMBB())
180    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
181  else
182    llvm_unreachable("Unexpected jump target operand kind.");
183  return 0;
184}
185
186unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
187                                                 unsigned OpNo) const {
188  MachineOperand MO = MI.getOperand(OpNo);
189  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
190  return 0;
191}
192
193unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
194                                         unsigned OpNo) const {
195  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
196  assert(MI.getOperand(OpNo).isReg());
197  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
198  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
199}
200
201unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
202                                             unsigned OpNo) const {
203  // size is encoded as size-1.
204  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
205}
206
207unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
208                                             unsigned OpNo) const {
209  // size is encoded as pos+size-1.
210  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
211         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
212}
213
214/// getMachineOpValue - Return binary encoding of operand. If the machine
215/// operand requires relocation, record the relocation and return zero.
216unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
217                                            const MachineOperand &MO) const {
218  if (MO.isReg())
219    return getMipsRegisterNumbering(MO.getReg());
220  else if (MO.isImm())
221    return static_cast<unsigned>(MO.getImm());
222  else if (MO.isGlobal()) {
223    if (MI.getOpcode() == Mips::ULW || MI.getOpcode() == Mips::USW ||
224          MI.getOpcode() == Mips::ULH || MI.getOpcode() == Mips::ULHu)
225      emitGlobalAddressUnaligned(MO.getGlobal(), getRelocation(MI, MO), 4);
226    else if (MI.getOpcode() == Mips::USH)
227      emitGlobalAddressUnaligned(MO.getGlobal(), getRelocation(MI, MO), 8);
228    else
229      emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
230  } else if (MO.isSymbol())
231    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
232  else if (MO.isCPI())
233    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
234  else if (MO.isJTI())
235    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
236  else if (MO.isMBB())
237    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
238  else
239    llvm_unreachable("Unable to encode MachineOperand!");
240  return 0;
241}
242
243void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
244                                        bool MayNeedFarStub) const {
245  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
246                                             const_cast<GlobalValue *>(GV), 0,
247                                             MayNeedFarStub));
248}
249
250void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
251                                           unsigned Reloc, int Offset) const {
252  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
253                             const_cast<GlobalValue *>(GV), 0, false));
254  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
255                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
256}
257
258void MipsCodeEmitter::
259emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
260  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
261                                                 Reloc, ES, 0, 0, false));
262}
263
264void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
265  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
266                                                    Reloc, CPI, 0, false));
267}
268
269void MipsCodeEmitter::
270emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
271  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
272                                                    Reloc, JTIndex, 0, false));
273}
274
275void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
276                                            unsigned Reloc) const {
277  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
278                                             Reloc, BB));
279}
280
281int MipsCodeEmitter::emitUSW(const MachineInstr &MI) {
282  unsigned src = getMachineOpValue(MI, MI.getOperand(0));
283  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
284  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
285  // swr src, offset(base)
286  // swl src, offset+3(base)
287  MCE.emitWordLE(
288    (0x2e << 26) | (base << 21) | (src << 16) | (offset & 0xffff));
289  MCE.emitWordLE(
290    (0x2a << 26) | (base << 21) | (src << 16) | ((offset+3) & 0xffff));
291  return 2;
292}
293
294int MipsCodeEmitter::emitULW(const MachineInstr &MI) {
295  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
296  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
297  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
298  unsigned at = 1;
299  if (dst != base) {
300    // lwr dst, offset(base)
301    // lwl dst, offset+3(base)
302    MCE.emitWordLE(
303      (0x26 << 26) | (base << 21) | (dst << 16) | (offset & 0xffff));
304    MCE.emitWordLE(
305      (0x22 << 26) | (base << 21) | (dst << 16) | ((offset+3) & 0xffff));
306    return 2;
307  } else {
308    // lwr at, offset(base)
309    // lwl at, offset+3(base)
310    // addu dst, at, $zero
311    MCE.emitWordLE(
312      (0x26 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
313    MCE.emitWordLE(
314      (0x22 << 26) | (base << 21) | (at << 16) | ((offset+3) & 0xffff));
315    MCE.emitWordLE(
316      (0x0 << 26) | (at << 21) | (0x0 << 16) | (dst << 11) | (0x0 << 6) | 0x21);
317    return 3;
318  }
319}
320
321int MipsCodeEmitter::emitUSH(const MachineInstr &MI) {
322  unsigned src = getMachineOpValue(MI, MI.getOperand(0));
323  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
324  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
325  unsigned at = 1;
326  // sb src, offset(base)
327  // srl at,src,8
328  // sb at, offset+1(base)
329  MCE.emitWordLE(
330    (0x28 << 26) | (base << 21) | (src << 16) | (offset & 0xffff));
331  MCE.emitWordLE(
332    (0x0 << 26) | (0x0 << 21) | (src << 16) | (at << 11) | (0x8 << 6) | 0x2);
333  MCE.emitWordLE(
334    (0x28 << 26) | (base << 21) | (at << 16) | ((offset+1) & 0xffff));
335  return 3;
336}
337
338int MipsCodeEmitter::emitULH(const MachineInstr &MI) {
339  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
340  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
341  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
342  unsigned at = 1;
343  // lbu at, offset(base)
344  // lb dst, offset+1(base)
345  // sll dst,dst,8
346  // or dst,dst,at
347  MCE.emitWordLE(
348    (0x24 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
349  MCE.emitWordLE(
350    (0x20 << 26) | (base << 21) | (dst << 16) | ((offset+1) & 0xffff));
351  MCE.emitWordLE(
352    (0x0 << 26) | (0x0 << 21) | (dst << 16) | (dst << 11) | (0x8 << 6) | 0x0);
353  MCE.emitWordLE(
354    (0x0 << 26) | (dst << 21) | (at << 16) | (dst << 11) | (0x0 << 6) | 0x25);
355  return 4;
356}
357
358int MipsCodeEmitter::emitULHu(const MachineInstr &MI) {
359  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
360  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
361  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
362  unsigned at = 1;
363  // lbu at, offset(base)
364  // lbu dst, offset+1(base)
365  // sll dst,dst,8
366  // or dst,dst,at
367  MCE.emitWordLE(
368    (0x24 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
369  MCE.emitWordLE(
370    (0x24 << 26) | (base << 21) | (dst << 16) | ((offset+1) & 0xffff));
371  MCE.emitWordLE(
372    (0x0 << 26) | (0x0 << 21) | (dst << 16) | (dst << 11) | (0x8 << 6) | 0x0);
373  MCE.emitWordLE(
374    (0x0 << 26) | (dst << 21) | (at << 16) | (dst << 11) | (0x0 << 6) | 0x25);
375  return 4;
376}
377
378void MipsCodeEmitter::emitInstruction(const MachineInstr &MI) {
379  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << MI);
380
381  MCE.processDebugLoc(MI.getDebugLoc(), true);
382
383  // Skip pseudo instructions.
384  if ((MI.getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo)
385    return;
386
387
388  switch (MI.getOpcode()) {
389  case Mips::USW:
390    NumEmitted += emitUSW(MI);
391    break;
392  case Mips::ULW:
393    NumEmitted += emitULW(MI);
394    break;
395  case Mips::ULH:
396    NumEmitted += emitULH(MI);
397    break;
398  case Mips::ULHu:
399    NumEmitted += emitULHu(MI);
400    break;
401  case Mips::USH:
402    NumEmitted += emitUSH(MI);
403    break;
404
405  default:
406    emitWordLE(getBinaryCodeForInstr(MI));
407    ++NumEmitted;  // Keep track of the # of mi's emitted
408    break;
409  }
410
411  MCE.processDebugLoc(MI.getDebugLoc(), false);
412}
413
414void MipsCodeEmitter::emitWordLE(unsigned Word) {
415  DEBUG(errs() << "  0x";
416        errs().write_hex(Word) << "\n");
417  MCE.emitWordLE(Word);
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