MipsCodeEmitter.cpp revision 25752e7be73d53ded2643f90d4344463c2cbf222 
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/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 DataLayout *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.getDataLayout()), 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    void emitGlobalAddressUnaligned(const GlobalValue *GV, unsigned Reloc,
116                                    int Offset) const;
117  };
118}
119
120char MipsCodeEmitter::ID = 0;
121
122bool MipsCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
123  JTI = ((MipsTargetMachine&) MF.getTarget()).getJITInfo();
124  II = ((const MipsTargetMachine&) MF.getTarget()).getInstrInfo();
125  TD = ((const MipsTargetMachine&) MF.getTarget()).getDataLayout();
126  Subtarget = &TM.getSubtarget<MipsSubtarget> ();
127  MCPEs = &MF.getConstantPool()->getConstants();
128  MJTEs = 0;
129  if (MF.getJumpTableInfo()) MJTEs = &MF.getJumpTableInfo()->getJumpTables();
130  JTI->Initialize(MF, IsPIC);
131  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo> ());
132
133  do {
134    DEBUG(errs() << "JITTing function '"
135        << MF.getName() << "'\n");
136    MCE.startFunction(MF);
137
138    for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
139        MBB != E; ++MBB){
140      MCE.StartMachineBasicBlock(MBB);
141      for (MachineBasicBlock::instr_iterator I = MBB->instr_begin(),
142           E = MBB->instr_end(); I != E; ++I)
143        emitInstruction(*I);
144    }
145  } while (MCE.finishFunction(MF));
146
147  return false;
148}
149
150unsigned MipsCodeEmitter::getRelocation(const MachineInstr &MI,
151                                        const MachineOperand &MO) const {
152  // NOTE: This relocations are for static.
153  uint64_t TSFlags = MI.getDesc().TSFlags;
154  uint64_t Form = TSFlags & MipsII::FormMask;
155  if (Form == MipsII::FrmJ)
156    return Mips::reloc_mips_26;
157  if ((Form == MipsII::FrmI || Form == MipsII::FrmFI)
158       && MI.isBranch())
159    return Mips::reloc_mips_pc16;
160  if (Form == MipsII::FrmI && MI.getOpcode() == Mips::LUi)
161    return Mips::reloc_mips_hi;
162  return Mips::reloc_mips_lo;
163}
164
165unsigned MipsCodeEmitter::getJumpTargetOpValue(const MachineInstr &MI,
166                                               unsigned OpNo) const {
167  MachineOperand MO = MI.getOperand(OpNo);
168  if (MO.isGlobal())
169    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
170  else if (MO.isSymbol())
171    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
172  else if (MO.isMBB())
173    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
174  else
175    llvm_unreachable("Unexpected jump target operand kind.");
176  return 0;
177}
178
179unsigned MipsCodeEmitter::getBranchTargetOpValue(const MachineInstr &MI,
180                                                 unsigned OpNo) const {
181  MachineOperand MO = MI.getOperand(OpNo);
182  emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
183  return 0;
184}
185
186unsigned MipsCodeEmitter::getMemEncoding(const MachineInstr &MI,
187                                         unsigned OpNo) const {
188  // Base register is encoded in bits 20-16, offset is encoded in bits 15-0.
189  assert(MI.getOperand(OpNo).isReg());
190  unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo)) << 16;
191  return (getMachineOpValue(MI, MI.getOperand(OpNo+1)) & 0xFFFF) | RegBits;
192}
193
194unsigned MipsCodeEmitter::getSizeExtEncoding(const MachineInstr &MI,
195                                             unsigned OpNo) const {
196  // size is encoded as size-1.
197  return getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
198}
199
200unsigned MipsCodeEmitter::getSizeInsEncoding(const MachineInstr &MI,
201                                             unsigned OpNo) const {
202  // size is encoded as pos+size-1.
203  return getMachineOpValue(MI, MI.getOperand(OpNo-1)) +
204         getMachineOpValue(MI, MI.getOperand(OpNo)) - 1;
205}
206
207/// getMachineOpValue - Return binary encoding of operand. If the machine
208/// operand requires relocation, record the relocation and return zero.
209unsigned MipsCodeEmitter::getMachineOpValue(const MachineInstr &MI,
210                                            const MachineOperand &MO) const {
211  if (MO.isReg())
212    return getMipsRegisterNumbering(MO.getReg());
213  else if (MO.isImm())
214    return static_cast<unsigned>(MO.getImm());
215  else if (MO.isGlobal())
216    emitGlobalAddress(MO.getGlobal(), getRelocation(MI, MO), true);
217  else if (MO.isSymbol())
218    emitExternalSymbolAddress(MO.getSymbolName(), getRelocation(MI, MO));
219  else if (MO.isCPI())
220    emitConstPoolAddress(MO.getIndex(), getRelocation(MI, MO));
221  else if (MO.isJTI())
222    emitJumpTableAddress(MO.getIndex(), getRelocation(MI, MO));
223  else if (MO.isMBB())
224    emitMachineBasicBlock(MO.getMBB(), getRelocation(MI, MO));
225  else
226    llvm_unreachable("Unable to encode MachineOperand!");
227  return 0;
228}
229
230void MipsCodeEmitter::emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
231                                        bool MayNeedFarStub) const {
232  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
233                                             const_cast<GlobalValue *>(GV), 0,
234                                             MayNeedFarStub));
235}
236
237void MipsCodeEmitter::emitGlobalAddressUnaligned(const GlobalValue *GV,
238                                           unsigned Reloc, int Offset) const {
239  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
240                             const_cast<GlobalValue *>(GV), 0, false));
241  MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset() + Offset,
242                      Reloc, const_cast<GlobalValue *>(GV), 0, false));
243}
244
245void MipsCodeEmitter::
246emitExternalSymbolAddress(const char *ES, unsigned Reloc) const {
247  MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
248                                                 Reloc, ES, 0, 0));
249}
250
251void MipsCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc) const {
252  MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
253                                                    Reloc, CPI, 0, false));
254}
255
256void MipsCodeEmitter::
257emitJumpTableAddress(unsigned JTIndex, unsigned Reloc) const {
258  MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
259                                                    Reloc, JTIndex, 0, false));
260}
261
262void MipsCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB,
263                                            unsigned Reloc) const {
264  MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
265                                             Reloc, BB));
266}
267
268void MipsCodeEmitter::emitInstruction(const MachineInstr &MI) {
269  DEBUG(errs() << "JIT: " << (void*)MCE.getCurrentPCValue() << ":\t" << MI);
270
271  MCE.processDebugLoc(MI.getDebugLoc(), true);
272
273  // Skip pseudo instructions.
274  if ((MI.getDesc().TSFlags & MipsII::FormMask) == MipsII::Pseudo)
275    return;
276
277  emitWordLE(getBinaryCodeForInstr(MI));
278  ++NumEmitted;  // Keep track of the # of mi's emitted
279
280  MCE.processDebugLoc(MI.getDebugLoc(), false);
281}
282
283void MipsCodeEmitter::emitWordLE(unsigned Word) {
284  DEBUG(errs() << "  0x";
285        errs().write_hex(Word) << "\n");
286  MCE.emitWordLE(Word);
287}
288
289/// createMipsJITCodeEmitterPass - Return a pass that emits the collected Mips
290/// code to the specified MCE object.
291FunctionPass *llvm::createMipsJITCodeEmitterPass(MipsTargetMachine &TM,
292                                                 JITCodeEmitter &JCE) {
293  return new MipsCodeEmitter(TM, JCE);
294}
295
296#include "MipsGenCodeEmitter.inc"
297