MipsCodeEmitter.cpp revision 82099683060abb1f74453d06e78a3729a75ef7ee 
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 "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    unsigned 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_branch;
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  // FIXME: implement
175  return 0;
176}
177
178unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
179                                                 unsigned OpNo) const {
180  // FIXME: implement
181  return 0;
182}
183
184unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
185                                         unsigned OpNo) const {
186  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
187  assert(MI.getOperand(OpNo).isReg());
188  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
189  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
190}
191
192unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
193                                             unsigned OpNo) const {
194  // size is encoded as size-1.
195  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
196}
197
198unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
199                                             unsigned OpNo) const {
200  // size is encoded as pos+size-1.
201  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
202         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
203}
204
205/// getMachineOpValue - Return binary encoding of operand. If the machine
206/// operand requires relocation, record the relocation and return zero.
207unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
208                                            const MachineOperand &MO) const {
209  if (MO.isReg())
210    return MipsRegisterInfo::getRegisterNumbering(MO.getReg());
211  else if (MO.isImm())
212    return static_cast<unsigned>(MO.getImm());
213  else if (MO.isGlobal()) {
214    if (MI.getOpcode() == Mips::ULW || MI.getOpcode() == Mips::USW ||
215          MI.getOpcode() == Mips::ULH || MI.getOpcode() == Mips::ULHu)
216      emitGlobalAddressUnaligned(MO.getGlobal(), getRelocation(MI, MO), 4);
217    else if (MI.getOpcode() == Mips::USH)
218      emitGlobalAddressUnaligned(MO.getGlobal(), getRelocation(MI, MO), 8);
219    else
220      emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
221  } else if (MO.isSymbol())
222    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
223  else if (MO.isCPI())
224    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
225  else if (MO.isJTI())
226    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
227  else if (MO.isMBB())
228    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
229  else
230    llvm_unreachable("Unable to encode MachineOperand!");
231  return 0;
232}
233
234void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
235                                        bool MayNeedFarStub) const {
236  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
237                                             const_cast<GlobalValue *>(GV), 0,
238                                             MayNeedFarStub));
239}
240
241void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
242                                           unsigned Reloc, int Offset) const {
243  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
244                             const_cast<GlobalValue *>(GV), 0, false));
245  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
246                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
247}
248
249void MipsCodeEmitter::
250emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
251  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
252                                                 Reloc, ES, 0, 0, false));
253}
254
255void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
256  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
257                                                    Reloc, CPI, 0, false));
258}
259
260void MipsCodeEmitter::
261emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
262  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
263                                                    Reloc, JTIndex, 0, false));
264}
265
266void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
267                                            unsigned Reloc) const {
268  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
269                                             Reloc, BB));
270}
271
272int MipsCodeEmitter::emitUSW(const MachineInstr &MI) {
273  unsigned src = getMachineOpValue(MI, MI.getOperand(0));
274  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
275  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
276  // swr src, offset(base)
277  // swl src, offset+3(base)
278  MCE.emitWordLE(
279    (0x2e << 26) | (base << 21) | (src << 16) | (offset & 0xffff));
280  MCE.emitWordLE(
281    (0x2a << 26) | (base << 21) | (src << 16) | ((offset+3) & 0xffff));
282  return 2;
283}
284
285int MipsCodeEmitter::emitULW(const MachineInstr &MI) {
286  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
287  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
288  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
289  unsigned at = 1;
290  if (dst != base) {
291    // lwr dst, offset(base)
292    // lwl dst, offset+3(base)
293    MCE.emitWordLE(
294      (0x26 << 26) | (base << 21) | (dst << 16) | (offset & 0xffff));
295    MCE.emitWordLE(
296      (0x22 << 26) | (base << 21) | (dst << 16) | ((offset+3) & 0xffff));
297    return 2;
298  } else {
299    // lwr at, offset(base)
300    // lwl at, offset+3(base)
301    // addu dst, at, $zero
302    MCE.emitWordLE(
303      (0x26 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
304    MCE.emitWordLE(
305      (0x22 << 26) | (base << 21) | (at << 16) | ((offset+3) & 0xffff));
306    MCE.emitWordLE(
307      (0x0 << 26) | (at << 21) | (0x0 << 16) | (dst << 11) | (0x0 << 6) | 0x21);
308    return 3;
309  }
310}
311
312int MipsCodeEmitter::emitUSH(const MachineInstr &MI) {
313  unsigned src = getMachineOpValue(MI, MI.getOperand(0));
314  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
315  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
316  unsigned at = 1;
317  // sb src, offset(base)
318  // srl at,src,8
319  // sb at, offset+1(base)
320  MCE.emitWordLE(
321    (0x28 << 26) | (base << 21) | (src << 16) | (offset & 0xffff));
322  MCE.emitWordLE(
323    (0x0 << 26) | (0x0 << 21) | (src << 16) | (at << 11) | (0x8 << 6) | 0x2);
324  MCE.emitWordLE(
325    (0x28 << 26) | (base << 21) | (at << 16) | ((offset+1) & 0xffff));
326  return 3;
327}
328
329int MipsCodeEmitter::emitULH(const MachineInstr &MI) {
330  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
331  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
332  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
333  unsigned at = 1;
334  // lbu at, offset(base)
335  // lb dst, offset+1(base)
336  // sll dst,dst,8
337  // or dst,dst,at
338  MCE.emitWordLE(
339    (0x24 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
340  MCE.emitWordLE(
341    (0x20 << 26) | (base << 21) | (dst << 16) | ((offset+1) & 0xffff));
342  MCE.emitWordLE(
343    (0x0 << 26) | (0x0 << 21) | (dst << 16) | (dst << 11) | (0x8 << 6) | 0x0);
344  MCE.emitWordLE(
345    (0x0 << 26) | (dst << 21) | (at << 16) | (dst << 11) | (0x0 << 6) | 0x25);
346  return 4;
347}
348
349int MipsCodeEmitter::emitULHu(const MachineInstr &MI) {
350  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
351  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
352  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
353  unsigned at = 1;
354  // lbu at, offset(base)
355  // lbu dst, offset+1(base)
356  // sll dst,dst,8
357  // or dst,dst,at
358  MCE.emitWordLE(
359    (0x24 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
360  MCE.emitWordLE(
361    (0x24 << 26) | (base << 21) | (dst << 16) | ((offset+1) & 0xffff));
362  MCE.emitWordLE(
363    (0x0 << 26) | (0x0 << 21) | (dst << 16) | (dst << 11) | (0x8 << 6) | 0x0);
364  MCE.emitWordLE(
365    (0x0 << 26) | (dst << 21) | (at << 16) | (dst << 11) | (0x0 << 6) | 0x25);
366  return 4;
367}
368
369void MipsCodeEmitter::emitInstruction(const MachineInstr &MI) {
370  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << MI);
371
372  MCE.processDebugLoc(MI.getDebugLoc(), true);
373
374  // Skip pseudo instructions.
375  if ((MI.getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo)
376    return;
377
378
379  switch (MI.getOpcode()) {
380  case Mips::USW:
381    NumEmitted += emitUSW(MI);
382    break;
383  case Mips::ULW:
384    NumEmitted += emitULW(MI);
385    break;
386  case Mips::ULH:
387    NumEmitted += emitULH(MI);
388    break;
389  case Mips::ULHu:
390    NumEmitted += emitULHu(MI);
391    break;
392  case Mips::USH:
393    NumEmitted += emitUSH(MI);
394    break;
395
396  default:
397    emitWordLE(getBinaryCodeForInstr(MI));
398    ++NumEmitted;  // Keep track of the # of mi's emitted
399    break;
400  }
401
402  MCE.processDebugLoc(MI.getDebugLoc(), false);
403}
404
405void MipsCodeEmitter::emitWordLE(unsigned Word) {
406  DEBUG(errs() << "  0x";
407        errs().write_hex(Word) << "\n");
408  MCE.emitWordLE(Word);
409}
410
411/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
412/// code to the specified MCE object.
413FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
414                                                 JITCodeEmitter &JCE) {
415  return new MipsCodeEmitter(TM, JCE);
416}
417
418#include "MipsGenCodeEmitter.inc"
419