PPCCodeEmitter.cpp revision 34da72645a82e11bc7008bc567d63426ec4c5949 
1//===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC32 -------*- C++ -*-=//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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 bytecode 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    PPCCodeEmitter(TargetMachine &T, MachineCodeEmitter &M)
44      : TM(T), MCE(M) {}
45
46    const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
47
48    /// runOnMachineFunction - emits the given MachineFunction to memory
49    ///
50    bool runOnMachineFunction(MachineFunction &MF);
51
52    /// emitBasicBlock - emits the given MachineBasicBlock to memory
53    ///
54    void emitBasicBlock(MachineBasicBlock &MBB);
55
56    /// getValueBit - return the particular bit of Val
57    ///
58    unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
59
60    /// getBinaryCodeForInstr - This function, generated by the
61    /// CodeEmitterGenerator using TableGen, produces the binary encoding for
62    /// machine instructions.
63    ///
64    unsigned getBinaryCodeForInstr(MachineInstr &MI);
65  };
66}
67
68/// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
69/// to the specified MCE object.
70FunctionPass *llvm::createPPCCodeEmitterPass(PPCTargetMachine &TM,
71                                             MachineCodeEmitter &MCE) {
72  return new PPCCodeEmitter(TM, MCE);
73}
74
75#ifdef __APPLE__
76extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
77#endif
78
79bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
80  assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
81          MF.getTarget().getRelocationModel() != Reloc::Static) &&
82         "JIT relocation model must be set to static or default!");
83  do {
84    MovePCtoLROffset = 0;
85    MCE.startFunction(MF);
86    for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
87      emitBasicBlock(*BB);
88  } while (MCE.finishFunction(MF));
89
90  return false;
91}
92
93void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
94  MCE.StartMachineBasicBlock(&MBB);
95
96  for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
97    MachineInstr &MI = *I;
98    switch (MI.getOpcode()) {
99    default:
100      MCE.emitWordBE(getBinaryCodeForInstr(*I));
101      break;
102    case PPC::IMPLICIT_DEF_GPRC:
103    case PPC::IMPLICIT_DEF_G8RC:
104    case PPC::IMPLICIT_DEF_F8:
105    case PPC::IMPLICIT_DEF_F4:
106    case PPC::IMPLICIT_DEF_VRRC:
107      break; // pseudo opcode, no side effects
108    case PPC::MovePCtoLR:
109    case PPC::MovePCtoLR8:
110      assert(TM.getRelocationModel() == Reloc::PIC_);
111      MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
112      MCE.emitWordBE(0x48000005);   // bl 1
113      break;
114    }
115  }
116}
117
118int PPCCodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
119
120  intptr_t rv = 0; // Return value; defaults to 0 for unhandled cases
121                   // or things that get fixed up later by the JIT.
122  if (MO.isRegister()) {
123    rv = PPCRegisterInfo::getRegisterNumbering(MO.getReg());
124
125    // Special encoding for MTCRF and MFOCRF, which uses a bit mask for the
126    // register, not the register number directly.
127    if ((MI.getOpcode() == PPC::MTCRF || MI.getOpcode() == PPC::MFOCRF) &&
128        (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7)) {
129      rv = 0x80 >> rv;
130    }
131  } else if (MO.isImmediate()) {
132    rv = MO.getImmedValue();
133  } else if (MO.isGlobalAddress() || MO.isExternalSymbol() ||
134             MO.isConstantPoolIndex() || MO.isJumpTableIndex()) {
135    unsigned Reloc = 0;
136    if (MI.getOpcode() == PPC::BL || MI.getOpcode() == PPC::BL8)
137      Reloc = PPC::reloc_pcrel_bx;
138    else {
139      if (TM.getRelocationModel() == Reloc::PIC_) {
140        assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
141      }
142      switch (MI.getOpcode()) {
143      default: MI.dump(); assert(0 && "Unknown instruction for relocation!");
144      case PPC::LIS:
145      case PPC::LIS8:
146      case PPC::ADDIS:
147      case PPC::ADDIS8:
148        Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
149        break;
150      case PPC::LI:
151      case PPC::LI8:
152      case PPC::LA:
153      // Loads.
154      case PPC::LBZ:
155      case PPC::LBZ8:
156      case PPC::LHA:
157      case PPC::LHA8:
158      case PPC::LHZ:
159      case PPC::LHZ8:
160      case PPC::LWZ:
161      case PPC::LWZ8:
162      case PPC::LFS:
163      case PPC::LFD:
164
165      // Stores.
166      case PPC::STB:
167      case PPC::STB8:
168      case PPC::STH:
169      case PPC::STH8:
170      case PPC::STW:
171      case PPC::STW8:
172      case PPC::STFS:
173      case PPC::STFD:
174        Reloc = PPC::reloc_absolute_low;
175        break;
176
177      case PPC::LWA:
178      case PPC::LD:
179      case PPC::STD:
180      case PPC::STD_32:
181        Reloc = PPC::reloc_absolute_low_ix;
182        break;
183      }
184    }
185
186    MachineRelocation R;
187    if (MO.isGlobalAddress()) {
188      R = MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
189                                   MO.getGlobal(), 0);
190    } else if (MO.isExternalSymbol()) {
191      R = MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
192                                       Reloc, MO.getSymbolName(), 0);
193    } else if (MO.isConstantPoolIndex()) {
194      R = MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
195                                          Reloc, MO.getConstantPoolIndex(), 0);
196    } else {
197      assert(MO.isJumpTableIndex());
198      R = MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
199                                          Reloc, MO.getJumpTableIndex(), 0);
200    }
201
202    // If in PIC mode, we need to encode the negated address of the
203    // 'movepctolr' into the unrelocated field.  After relocation, we'll have
204    // &gv-&movepctolr-4 in the imm field.  Once &movepctolr is added to the imm
205    // field, we get &gv.  This doesn't happen for branch relocations, which are
206    // always implicitly pc relative.
207    if (TM.getRelocationModel() == Reloc::PIC_ && Reloc != PPC::reloc_pcrel_bx){
208      assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
209      R.setConstantVal(-(intptr_t)MovePCtoLROffset - 4);
210    }
211    MCE.addRelocation(R);
212
213  } else if (MO.isMachineBasicBlock()) {
214    unsigned Reloc = 0;
215    unsigned Opcode = MI.getOpcode();
216    if (Opcode == PPC::B || Opcode == PPC::BL || Opcode == PPC::BLA)
217      Reloc = PPC::reloc_pcrel_bx;
218    else // BCC instruction
219      Reloc = PPC::reloc_pcrel_bcx;
220    MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
221                                               Reloc,
222                                               MO.getMachineBasicBlock()));
223  } else {
224    cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
225    abort();
226  }
227
228  return rv;
229}
230
231#include "PPCGenCodeEmitter.inc"
232
233