MipsCodeEmitter.cpp revision 96601ca332ab388754ca4673be8973396fea2ddd 
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/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
43STATISTIC(NumEmitted, "Number of machine instructions emitted");
44
45namespace {
46
47class MipsCodeEmitter : public MachineFunctionPass {
48  MipsJITInfo *JTI;
49  const MipsInstrInfo *II;
50  const TargetData *TD;
51  const MipsSubtarget *Subtarget;
52  TargetMachine &TM;
53  JITCodeEmitter &MCE;
54  const std::vector<MachineConstantPoolEntry> *MCPEs;
55  const std::vector<MachineJumpTableEntry> *MJTEs;
56  bool IsPIC;
57
58  void getAnalysisUsage(AnalysisUsage &AU) const {
59    AU.addRequired<MachineModuleInfo> ();
60    MachineFunctionPass::getAnalysisUsage(AU);
61  }
62
63  static char ID;
64
65  public:
66    MipsCodeEmitter(TargetMachine &tm, JITCodeEmitter &mce) :
67      MachineFunctionPass(ID), JTI(0),
68      II((const MipsInstrInfo *) tm.getInstrInfo()),
69      TD(tm.getTargetData()), TM(tm), MCE(mce), MCPEs(0), MJTEs(0),
70      IsPIC(TM.getRelocationModel() == Reloc::PIC_) {
71    }
72
73    bool runOnMachineFunction(MachineFunction &MF);
74
75    virtual const char *getPassName() const {
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(const MachineInstr &MI);
85
86  private:
87
88    void emitWordLE(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,
110                                    unsigned OpNo) const;
111    unsigned getMemEncoding(const MachineInstr &MI, unsigned OpNo) const;
112    unsigned getSizeExtEncoding(const MachineInstr &MI, unsigned OpNo) const;
113    unsigned getSizeInsEncoding(const MachineInstr &MI, unsigned OpNo) const;
114
115    int emitULW(const MachineInstr &MI);
116    int emitUSW(const MachineInstr &MI);
117    int emitULH(const MachineInstr &MI);
118    int emitULHu(const MachineInstr &MI);
119    int emitUSH(const MachineInstr &MI);
120
121    void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
122                                    int Offset) const;
123  };
124}
125
126char MipsCodeEmitter::ID = 0;
127
128bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
129  JTI = ((MipsTargetMachine&) MF.getTarget()).getJITInfo();
130  II = ((const MipsTargetMachine&) MF.getTarget()).getInstrInfo();
131  TD = ((const MipsTargetMachine&) MF.getTarget()).getTargetData();
132  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
133  MCPEs = &MF.getConstantPool()->getConstants();
134  MJTEs = 0;
135  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
136  JTI->Initialize(MF, IsPIC);
137  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
138
139  do {
140    DEBUG(errs() << "JITTing function '"
141        << MF.getName() << "'\n");
142    MCE.startFunction(MF);
143
144    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
145        MBB != E; ++MBB){
146      MCE.StartMachineBasicBlock(MBB);
147      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
148           E = MBB->instr_end(); I != E; ++I)
149        emitInstruction(*I);
150    }
151  } while (MCE.finishFunction(MF));
152
153  return false;
154}
155
156unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
157                                        const MachineOperand &MO) const {
158  // NOTE: This relocations are for static.
159  uint64_t TSFlags = MI.getDesc().TSFlags;
160  uint64_t Form = TSFlags & MipsII::FormMask;
161  if (Form == MipsII::FrmJ)
162    return Mips::reloc_mips_26;
163  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
164       && MI.isBranch())
165    return Mips::reloc_mips_pc16;
166  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
167    return Mips::reloc_mips_hi;
168  return Mips::reloc_mips_lo;
169}
170
171unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
172                                               unsigned OpNo) const {
173  MachineOperand MO = MI.getOperand(OpNo);
174  if (MO.isGlobal())
175    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
176  else if (MO.isSymbol())
177    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
178  else if (MO.isMBB())
179    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
180  else
181    llvm_unreachable("Unexpected jump target operand kind.");
182  return 0;
183}
184
185unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
186                                                 unsigned OpNo) const {
187  MachineOperand MO = MI.getOperand(OpNo);
188  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
189  return 0;
190}
191
192unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
193                                         unsigned OpNo) const {
194  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
195  assert(MI.getOperand(OpNo).isReg());
196  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
197  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
198}
199
200unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
201                                             unsigned OpNo) const {
202  // size is encoded as size-1.
203  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
204}
205
206unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
207                                             unsigned OpNo) const {
208  // size is encoded as pos+size-1.
209  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
210         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
211}
212
213/// getMachineOpValue - Return binary encoding of operand. If the machine
214/// operand requires relocation, record the relocation and return zero.
215unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
216                                            const MachineOperand &MO) const {
217  if (MO.isReg())
218    return getMipsRegisterNumbering(MO.getReg());
219  else if (MO.isImm())
220    return static_cast<unsigned>(MO.getImm());
221  else if (MO.isGlobal()) {
222    if (MI.getOpcode() == Mips::ULW || MI.getOpcode() == Mips::USW ||
223          MI.getOpcode() == Mips::ULH || MI.getOpcode() == Mips::ULHu)
224      emitGlobalAddressUnaligned(MO.getGlobal(), getRelocation(MI, MO), 4);
225    else if (MI.getOpcode() == Mips::USH)
226      emitGlobalAddressUnaligned(MO.getGlobal(), getRelocation(MI, MO), 8);
227    else
228      emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
229  } else if (MO.isSymbol())
230    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
231  else if (MO.isCPI())
232    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
233  else if (MO.isJTI())
234    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
235  else if (MO.isMBB())
236    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
237  else
238    llvm_unreachable("Unable to encode MachineOperand!");
239  return 0;
240}
241
242void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
243                                        bool MayNeedFarStub) const {
244  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
245                                             const_cast<GlobalValue *>(GV), 0,
246                                             MayNeedFarStub));
247}
248
249void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
250                                           unsigned Reloc, int Offset) const {
251  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
252                             const_cast<GlobalValue *>(GV), 0, false));
253  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
254                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
255}
256
257void MipsCodeEmitter::
258emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
259  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
260                                                 Reloc, ES, 0, 0));
261}
262
263void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
264  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
265                                                    Reloc, CPI, 0, false));
266}
267
268void MipsCodeEmitter::
269emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
270  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
271                                                    Reloc, JTIndex, 0, false));
272}
273
274void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
275                                            unsigned Reloc) const {
276  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
277                                             Reloc, BB));
278}
279
280int MipsCodeEmitter::emitUSW(const MachineInstr &MI) {
281  unsigned src = getMachineOpValue(MI, MI.getOperand(0));
282  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
283  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
284  // swr src, offset(base)
285  // swl src, offset+3(base)
286  MCE.emitWordLE(
287    (0x2e << 26) | (base << 21) | (src << 16) | (offset & 0xffff));
288  MCE.emitWordLE(
289    (0x2a << 26) | (base << 21) | (src << 16) | ((offset+3) & 0xffff));
290  return 2;
291}
292
293int MipsCodeEmitter::emitULW(const MachineInstr &MI) {
294  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
295  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
296  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
297  unsigned at = 1;
298  if (dst != base) {
299    // lwr dst, offset(base)
300    // lwl dst, offset+3(base)
301    MCE.emitWordLE(
302      (0x26 << 26) | (base << 21) | (dst << 16) | (offset & 0xffff));
303    MCE.emitWordLE(
304      (0x22 << 26) | (base << 21) | (dst << 16) | ((offset+3) & 0xffff));
305    return 2;
306  } else {
307    // lwr at, offset(base)
308    // lwl at, offset+3(base)
309    // addu dst, at, $zero
310    MCE.emitWordLE(
311      (0x26 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
312    MCE.emitWordLE(
313      (0x22 << 26) | (base << 21) | (at << 16) | ((offset+3) & 0xffff));
314    MCE.emitWordLE(
315      (0x0 << 26) | (at << 21) | (0x0 << 16) | (dst << 11) | (0x0 << 6) | 0x21);
316    return 3;
317  }
318}
319
320int MipsCodeEmitter::emitUSH(const MachineInstr &MI) {
321  unsigned src = getMachineOpValue(MI, MI.getOperand(0));
322  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
323  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
324  unsigned at = 1;
325  // sb src, offset(base)
326  // srl at,src,8
327  // sb at, offset+1(base)
328  MCE.emitWordLE(
329    (0x28 << 26) | (base << 21) | (src << 16) | (offset & 0xffff));
330  MCE.emitWordLE(
331    (0x0 << 26) | (0x0 << 21) | (src << 16) | (at << 11) | (0x8 << 6) | 0x2);
332  MCE.emitWordLE(
333    (0x28 << 26) | (base << 21) | (at << 16) | ((offset+1) & 0xffff));
334  return 3;
335}
336
337int MipsCodeEmitter::emitULH(const MachineInstr &MI) {
338  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
339  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
340  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
341  unsigned at = 1;
342  // lbu at, offset(base)
343  // lb dst, offset+1(base)
344  // sll dst,dst,8
345  // or dst,dst,at
346  MCE.emitWordLE(
347    (0x24 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
348  MCE.emitWordLE(
349    (0x20 << 26) | (base << 21) | (dst << 16) | ((offset+1) & 0xffff));
350  MCE.emitWordLE(
351    (0x0 << 26) | (0x0 << 21) | (dst << 16) | (dst << 11) | (0x8 << 6) | 0x0);
352  MCE.emitWordLE(
353    (0x0 << 26) | (dst << 21) | (at << 16) | (dst << 11) | (0x0 << 6) | 0x25);
354  return 4;
355}
356
357int MipsCodeEmitter::emitULHu(const MachineInstr &MI) {
358  unsigned dst = getMachineOpValue(MI, MI.getOperand(0));
359  unsigned base = getMachineOpValue(MI, MI.getOperand(1));
360  unsigned offset = getMachineOpValue(MI, MI.getOperand(2));
361  unsigned at = 1;
362  // lbu at, offset(base)
363  // lbu dst, offset+1(base)
364  // sll dst,dst,8
365  // or dst,dst,at
366  MCE.emitWordLE(
367    (0x24 << 26) | (base << 21) | (at << 16) | (offset & 0xffff));
368  MCE.emitWordLE(
369    (0x24 << 26) | (base << 21) | (dst << 16) | ((offset+1) & 0xffff));
370  MCE.emitWordLE(
371    (0x0 << 26) | (0x0 << 21) | (dst << 16) | (dst << 11) | (0x8 << 6) | 0x0);
372  MCE.emitWordLE(
373    (0x0 << 26) | (dst << 21) | (at << 16) | (dst << 11) | (0x0 << 6) | 0x25);
374  return 4;
375}
376
377void MipsCodeEmitter::emitInstruction(const MachineInstr &MI) {
378  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << MI);
379
380  MCE.processDebugLoc(MI.getDebugLoc(), true);
381
382  // Skip pseudo instructions.
383  if ((MI.getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo)
384    return;
385
386
387  switch (MI.getOpcode()) {
388  case Mips::USW:
389    NumEmitted += emitUSW(MI);
390    break;
391  case Mips::ULW:
392    NumEmitted += emitULW(MI);
393    break;
394  case Mips::ULH:
395    NumEmitted += emitULH(MI);
396    break;
397  case Mips::ULHu:
398    NumEmitted += emitULHu(MI);
399    break;
400  case Mips::USH:
401    NumEmitted += emitUSH(MI);
402    break;
403
404  default:
405    emitWordLE(getBinaryCodeForInstr(MI));
406    ++NumEmitted;  // Keep track of the # of mi's emitted
407    break;
408  }
409
410  MCE.processDebugLoc(MI.getDebugLoc(), false);
411}
412
413void MipsCodeEmitter::emitWordLE(unsigned Word) {
414  DEBUG(errs() << "  0x";
415        errs().write_hex(Word) << "\n");
416  MCE.emitWordLE(Word);
417}
418
419/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
420/// code to the specified MCE object.
421FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
422                                                 JITCodeEmitter &JCE) {
423  return new MipsCodeEmitter(TM, JCE);
424}
425
426#include "MipsGenCodeEmitter.inc"
427