PPCCodeEmitter.cpp revision 165b60de0b4a17e7d270e63fd4223b6c1c318fdd 
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/Passes.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/Compiler.h"
26#include "llvm/Target/TargetOptions.h"
27using namespace llvm;
28
29namespace {
30  class VISIBILITY_HIDDEN PPCCodeEmitter : public MachineFunctionPass {
31    TargetMachine &TM;
32    MachineCodeEmitter &MCE;
33
34    /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
35    /// its address in the function into this pointer.
36    void *MovePCtoLROffset;
37
38    /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
39    ///
40    int getMachineOpValue(MachineInstr &MI, MachineOperand &MO);
41
42  public:
43    static char ID;
44    PPCCodeEmitter(TargetMachine &T, MachineCodeEmitter &M)
45      : MachineFunctionPass((intptr_t)&ID), TM(T), MCE(M) {}
46
47    const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
48
49    /// runOnMachineFunction - emits the given MachineFunction to memory
50    ///
51    bool runOnMachineFunction(MachineFunction &MF);
52
53    /// emitBasicBlock - emits the given MachineBasicBlock to memory
54    ///
55    void emitBasicBlock(MachineBasicBlock &MBB);
56
57    /// getValueBit - return the particular bit of Val
58    ///
59    unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
60
61    /// getBinaryCodeForInstr - This function, generated by the
62    /// CodeEmitterGenerator using TableGen, produces the binary encoding for
63    /// machine instructions.
64    ///
65    unsigned getBinaryCodeForInstr(MachineInstr &MI);
66  };
67  char PPCCodeEmitter::ID = 0;
68}
69
70/// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
71/// to the specified MCE object.
72FunctionPass *llvm::createPPCCodeEmitterPass(PPCTargetMachine &TM,
73                                             MachineCodeEmitter &MCE) {
74  return new PPCCodeEmitter(TM, MCE);
75}
76
77#ifdef __APPLE__
78extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
79#endif
80
81bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
82  assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
83          MF.getTarget().getRelocationModel() != Reloc::Static) &&
84         "JIT relocation model must be set to static or default!");
85  do {
86    MovePCtoLROffset = 0;
87    MCE.startFunction(MF);
88    for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
89      emitBasicBlock(*BB);
90  } while (MCE.finishFunction(MF));
91
92  return false;
93}
94
95void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
96  MCE.StartMachineBasicBlock(&MBB);
97
98  for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
99    MachineInstr &MI = *I;
100    switch (MI.getOpcode()) {
101    default:
102      MCE.emitWordBE(getBinaryCodeForInstr(*I));
103      break;
104    case PPC::IMPLICIT_DEF_GPRC:
105    case PPC::IMPLICIT_DEF_G8RC:
106    case PPC::IMPLICIT_DEF_F8:
107    case PPC::IMPLICIT_DEF_F4:
108    case PPC::IMPLICIT_DEF_VRRC:
109      break; // pseudo opcode, no side effects
110    case PPC::MovePCtoLR:
111    case PPC::MovePCtoLR8:
112      assert(TM.getRelocationModel() == Reloc::PIC_);
113      MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
114      MCE.emitWordBE(0x48000005);   // bl 1
115      break;
116    }
117  }
118}
119
120int PPCCodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
121
122  intptr_t rv = 0; // Return value; defaults to 0 for unhandled cases
123                   // or things that get fixed up later by the JIT.
124  if (MO.isRegister()) {
125    rv = PPCRegisterInfo::getRegisterNumbering(MO.getReg());
126
127    // Special encoding for MTCRF and MFOCRF, which uses a bit mask for the
128    // register, not the register number directly.
129    if ((MI.getOpcode() == PPC::MTCRF || MI.getOpcode() == PPC::MFOCRF) &&
130        (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7)) {
131      rv = 0x80 >> rv;
132    }
133  } else if (MO.isImmediate()) {
134    rv = MO.getImm();
135  } else if (MO.isGlobalAddress() || MO.isExternalSymbol() ||
136             MO.isConstantPoolIndex() || MO.isJumpTableIndex()) {
137    unsigned Reloc = 0;
138    if (MI.getOpcode() == PPC::BL_Macho || MI.getOpcode() == PPC::BL8_Macho ||
139        MI.getOpcode() == PPC::BL_ELF || MI.getOpcode() == PPC::BL8_ELF)
140      Reloc = PPC::reloc_pcrel_bx;
141    else {
142      if (TM.getRelocationModel() == Reloc::PIC_) {
143        assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
144      }
145      switch (MI.getOpcode()) {
146      default: MI.dump(); assert(0 && "Unknown instruction for relocation!");
147      case PPC::LIS:
148      case PPC::LIS8:
149      case PPC::ADDIS:
150      case PPC::ADDIS8:
151        Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
152        break;
153      case PPC::LI:
154      case PPC::LI8:
155      case PPC::LA:
156      // Loads.
157      case PPC::LBZ:
158      case PPC::LBZ8:
159      case PPC::LHA:
160      case PPC::LHA8:
161      case PPC::LHZ:
162      case PPC::LHZ8:
163      case PPC::LWZ:
164      case PPC::LWZ8:
165      case PPC::LFS:
166      case PPC::LFD:
167
168      // Stores.
169      case PPC::STB:
170      case PPC::STB8:
171      case PPC::STH:
172      case PPC::STH8:
173      case PPC::STW:
174      case PPC::STW8:
175      case PPC::STFS:
176      case PPC::STFD:
177        Reloc = PPC::reloc_absolute_low;
178        break;
179
180      case PPC::LWA:
181      case PPC::LD:
182      case PPC::STD:
183      case PPC::STD_32:
184        Reloc = PPC::reloc_absolute_low_ix;
185        break;
186      }
187    }
188
189    MachineRelocation R;
190    if (MO.isGlobalAddress()) {
191      R = MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
192                                   MO.getGlobal(), 0,
193                                   isa<Function>(MO.getGlobal()));
194    } else if (MO.isExternalSymbol()) {
195      R = MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
196                                       Reloc, MO.getSymbolName(), 0);
197    } else if (MO.isConstantPoolIndex()) {
198      R = MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
199                                          Reloc, MO.getIndex(), 0);
200    } else {
201      assert(MO.isJumpTableIndex());
202      R = MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
203                                          Reloc, MO.getIndex(), 0);
204    }
205
206    // If in PIC mode, we need to encode the negated address of the
207    // 'movepctolr' into the unrelocated field.  After relocation, we'll have
208    // &gv-&movepctolr-4 in the imm field.  Once &movepctolr is added to the imm
209    // field, we get &gv.  This doesn't happen for branch relocations, which are
210    // always implicitly pc relative.
211    if (TM.getRelocationModel() == Reloc::PIC_ && Reloc != PPC::reloc_pcrel_bx){
212      assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
213      R.setConstantVal(-(intptr_t)MovePCtoLROffset - 4);
214    }
215    MCE.addRelocation(R);
216
217  } else if (MO.isMachineBasicBlock()) {
218    unsigned Reloc = 0;
219    unsigned Opcode = MI.getOpcode();
220    if (Opcode == PPC::B || Opcode == PPC::BL_Macho ||
221        Opcode == PPC::BLA_Macho || Opcode == PPC::BL_ELF ||
222        Opcode == PPC::BLA_ELF)
223      Reloc = PPC::reloc_pcrel_bx;
224    else // BCC instruction
225      Reloc = PPC::reloc_pcrel_bcx;
226    MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
227                                               Reloc, MO.getMBB()));
228  } else {
229    cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
230    abort();
231  }
232
233  return rv;
234}
235
236#include "PPCGenCodeEmitter.inc"
237
238