PPCCodeEmitter.cpp revision d18330763965745fea05536939f5aadffcc6a5a6 
1//===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC32 -------*- 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 defines the PowerPC 32-bit CodeEmitter and associated machinery to
11// JIT-compile bitcode to native PowerPC.
12//
13//===----------------------------------------------------------------------===//
14
15#include "PPCTargetMachine.h"
16#include "PPCRelocations.h"
17#include "PPC.h"
18#include "llvm/Module.h"
19#include "llvm/PassManager.h"
20#include "llvm/CodeGen/MachineCodeEmitter.h"
21#include "llvm/CodeGen/MachineFunctionPass.h"
22#include "llvm/CodeGen/MachineInstrBuilder.h"
23#include "llvm/CodeGen/MachineModuleInfo.h"
24#include "llvm/CodeGen/Passes.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/Compiler.h"
27#include "llvm/Target/TargetOptions.h"
28using namespace llvm;
29
30namespace {
31  class VISIBILITY_HIDDEN PPCCodeEmitter : public MachineFunctionPass {
32    TargetMachine &TM;
33    MachineCodeEmitter &MCE;
34
35    /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
36    /// its address in the function into this pointer.
37    void *MovePCtoLROffset;
38
39    /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
40    ///
41    int getMachineOpValue(MachineInstr &MI, MachineOperand &MO);
42
43    void getAnalysisUsage(AnalysisUsage &AU) const {
44      AU.addRequired<MachineModuleInfo>();
45      MachineFunctionPass::getAnalysisUsage(AU);
46    }
47
48  public:
49    static char ID;
50    PPCCodeEmitter(TargetMachine &T, MachineCodeEmitter &M)
51      : MachineFunctionPass((intptr_t)&ID), TM(T), MCE(M) {}
52
53    const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
54
55    /// runOnMachineFunction - emits the given MachineFunction to memory
56    ///
57    bool runOnMachineFunction(MachineFunction &MF);
58
59    /// emitBasicBlock - emits the given MachineBasicBlock to memory
60    ///
61    void emitBasicBlock(MachineBasicBlock &MBB);
62
63    /// getValueBit - return the particular bit of Val
64    ///
65    unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
66
67    /// getBinaryCodeForInstr - This function, generated by the
68    /// CodeEmitterGenerator using TableGen, produces the binary encoding for
69    /// machine instructions.
70    ///
71    unsigned getBinaryCodeForInstr(MachineInstr &MI);
72  };
73  char PPCCodeEmitter::ID = 0;
74}
75
76/// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
77/// to the specified MCE object.
78FunctionPass *llvm::createPPCCodeEmitterPass(PPCTargetMachine &TM,
79                                             MachineCodeEmitter &MCE) {
80  return new PPCCodeEmitter(TM, MCE);
81}
82
83#ifdef __APPLE__
84extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
85#endif
86
87bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
88  assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
89          MF.getTarget().getRelocationModel() != Reloc::Static) &&
90         "JIT relocation model must be set to static or default!");
91
92  MCE.setModuleInfo(&getAnalysis<MachineModuleInfo>());
93  do {
94    MovePCtoLROffset = 0;
95    MCE.startFunction(MF);
96    for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
97      emitBasicBlock(*BB);
98  } while (MCE.finishFunction(MF));
99
100  return false;
101}
102
103void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
104  MCE.StartMachineBasicBlock(&MBB);
105
106  for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
107    MachineInstr &MI = *I;
108    switch (MI.getOpcode()) {
109    default:
110      MCE.emitWordBE(getBinaryCodeForInstr(*I));
111      break;
112    case TargetInstrInfo::LABEL:
113      MCE.emitLabel(MI.getOperand(0).getImm());
114      break;
115    case TargetInstrInfo::IMPLICIT_DEF:
116      break; // pseudo opcode, no side effects
117    case PPC::MovePCtoLR:
118    case PPC::MovePCtoLR8:
119      assert(TM.getRelocationModel() == Reloc::PIC_);
120      MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
121      MCE.emitWordBE(0x48000005);   // bl 1
122      break;
123    }
124  }
125}
126
127int PPCCodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
128
129  intptr_t rv = 0; // Return value; defaults to 0 for unhandled cases
130                   // or things that get fixed up later by the JIT.
131  if (MO.isRegister()) {
132    rv = PPCRegisterInfo::getRegisterNumbering(MO.getReg());
133
134    // Special encoding for MTCRF and MFOCRF, which uses a bit mask for the
135    // register, not the register number directly.
136    if ((MI.getOpcode() == PPC::MTCRF || MI.getOpcode() == PPC::MFOCRF) &&
137        (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7)) {
138      rv = 0x80 >> rv;
139    }
140  } else if (MO.isImmediate()) {
141    rv = MO.getImm();
142  } else if (MO.isGlobalAddress() || MO.isExternalSymbol() ||
143             MO.isConstantPoolIndex() || MO.isJumpTableIndex()) {
144    unsigned Reloc = 0;
145    if (MI.getOpcode() == PPC::BL_Macho || MI.getOpcode() == PPC::BL8_Macho ||
146        MI.getOpcode() == PPC::BL_ELF || MI.getOpcode() == PPC::BL8_ELF)
147      Reloc = PPC::reloc_pcrel_bx;
148    else {
149      if (TM.getRelocationModel() == Reloc::PIC_) {
150        assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
151      }
152      switch (MI.getOpcode()) {
153      default: MI.dump(); assert(0 && "Unknown instruction for relocation!");
154      case PPC::LIS:
155      case PPC::LIS8:
156      case PPC::ADDIS:
157      case PPC::ADDIS8:
158        Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
159        break;
160      case PPC::LI:
161      case PPC::LI8:
162      case PPC::LA:
163      // Loads.
164      case PPC::LBZ:
165      case PPC::LBZ8:
166      case PPC::LHA:
167      case PPC::LHA8:
168      case PPC::LHZ:
169      case PPC::LHZ8:
170      case PPC::LWZ:
171      case PPC::LWZ8:
172      case PPC::LFS:
173      case PPC::LFD:
174
175      // Stores.
176      case PPC::STB:
177      case PPC::STB8:
178      case PPC::STH:
179      case PPC::STH8:
180      case PPC::STW:
181      case PPC::STW8:
182      case PPC::STFS:
183      case PPC::STFD:
184        Reloc = PPC::reloc_absolute_low;
185        break;
186
187      case PPC::LWA:
188      case PPC::LD:
189      case PPC::STD:
190      case PPC::STD_32:
191        Reloc = PPC::reloc_absolute_low_ix;
192        break;
193      }
194    }
195
196    MachineRelocation R;
197    if (MO.isGlobalAddress()) {
198      R = MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
199                                   MO.getGlobal(), 0,
200                                   isa<Function>(MO.getGlobal()));
201    } else if (MO.isExternalSymbol()) {
202      R = MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
203                                       Reloc, MO.getSymbolName(), 0);
204    } else if (MO.isConstantPoolIndex()) {
205      R = MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
206                                          Reloc, MO.getIndex(), 0);
207    } else {
208      assert(MO.isJumpTableIndex());
209      R = MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
210                                          Reloc, MO.getIndex(), 0);
211    }
212
213    // If in PIC mode, we need to encode the negated address of the
214    // 'movepctolr' into the unrelocated field.  After relocation, we'll have
215    // &gv-&movepctolr-4 in the imm field.  Once &movepctolr is added to the imm
216    // field, we get &gv.  This doesn't happen for branch relocations, which are
217    // always implicitly pc relative.
218    if (TM.getRelocationModel() == Reloc::PIC_ && Reloc != PPC::reloc_pcrel_bx){
219      assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
220      R.setConstantVal(-(intptr_t)MovePCtoLROffset - 4);
221    }
222    MCE.addRelocation(R);
223
224  } else if (MO.isMachineBasicBlock()) {
225    unsigned Reloc = 0;
226    unsigned Opcode = MI.getOpcode();
227    if (Opcode == PPC::B || Opcode == PPC::BL_Macho ||
228        Opcode == PPC::BLA_Macho || Opcode == PPC::BL_ELF ||
229        Opcode == PPC::BLA_ELF)
230      Reloc = PPC::reloc_pcrel_bx;
231    else // BCC instruction
232      Reloc = PPC::reloc_pcrel_bcx;
233    MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
234                                               Reloc, MO.getMBB()));
235  } else {
236    cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
237    abort();
238  }
239
240  return rv;
241}
242
243#include "PPCGenCodeEmitter.inc"
244
245