aboutsummaryrefslogtreecommitdiffstats
path: root/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
blob: c54d5e75bdfd7f5937c97daa34906b1c5a034540 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
//===-- PPCAsmBackend.cpp - PPC Assembler Backend -------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "MCTargetDesc/PPCMCTargetDesc.h"
#include "MCTargetDesc/PPCFixupKinds.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCELF.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCMachObjectWriter.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MachO.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;

static uint64_t adjustFixupValue(unsigned Kind, uint64_t Value) {
  switch (Kind) {
  default:
    llvm_unreachable("Unknown fixup kind!");
  case FK_Data_1:
  case FK_Data_2:
  case FK_Data_4:
  case FK_Data_8:
  case PPC::fixup_ppc_nofixup:
    return Value;
  case PPC::fixup_ppc_brcond14:
  case PPC::fixup_ppc_brcond14abs:
    return Value & 0xfffc;
  case PPC::fixup_ppc_br24:
  case PPC::fixup_ppc_br24abs:
    return Value & 0x3fffffc;
  case PPC::fixup_ppc_half16:
    return Value & 0xffff;
  case PPC::fixup_ppc_half16ds:
    return Value & 0xfffc;
  }
}

static unsigned getFixupKindNumBytes(unsigned Kind) {
  switch (Kind) {
  default:
    llvm_unreachable("Unknown fixup kind!");
  case FK_Data_1:
    return 1;
  case FK_Data_2:
  case PPC::fixup_ppc_half16:
  case PPC::fixup_ppc_half16ds:
    return 2;
  case FK_Data_4:
  case PPC::fixup_ppc_brcond14:
  case PPC::fixup_ppc_brcond14abs:
  case PPC::fixup_ppc_br24:
  case PPC::fixup_ppc_br24abs:
    return 4;
  case FK_Data_8:
    return 8;
  case PPC::fixup_ppc_nofixup:
    return 0;
  }
}

namespace {

class PPCAsmBackend : public MCAsmBackend {
  const Target &TheTarget;
  bool IsLittleEndian;
public:
  PPCAsmBackend(const Target &T, bool isLittle) : MCAsmBackend(), TheTarget(T),
    IsLittleEndian(isLittle) {}

  unsigned getNumFixupKinds() const override {
    return PPC::NumTargetFixupKinds;
  }

  const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override {
    const static MCFixupKindInfo InfosBE[PPC::NumTargetFixupKinds] = {
      // name                    offset  bits  flags
      { "fixup_ppc_br24",        6,      24,   MCFixupKindInfo::FKF_IsPCRel },
      { "fixup_ppc_brcond14",    16,     14,   MCFixupKindInfo::FKF_IsPCRel },
      { "fixup_ppc_br24abs",     6,      24,   0 },
      { "fixup_ppc_brcond14abs", 16,     14,   0 },
      { "fixup_ppc_half16",       0,     16,   0 },
      { "fixup_ppc_half16ds",     0,     14,   0 },
      { "fixup_ppc_nofixup",      0,      0,   0 }
    };
    const static MCFixupKindInfo InfosLE[PPC::NumTargetFixupKinds] = {
      // name                    offset  bits  flags
      { "fixup_ppc_br24",        2,      24,   MCFixupKindInfo::FKF_IsPCRel },
      { "fixup_ppc_brcond14",    2,      14,   MCFixupKindInfo::FKF_IsPCRel },
      { "fixup_ppc_br24abs",     2,      24,   0 },
      { "fixup_ppc_brcond14abs", 2,      14,   0 },
      { "fixup_ppc_half16",      0,      16,   0 },
      { "fixup_ppc_half16ds",    2,      14,   0 },
      { "fixup_ppc_nofixup",     0,       0,   0 }
    };

    if (Kind < FirstTargetFixupKind)
      return MCAsmBackend::getFixupKindInfo(Kind);

    assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
           "Invalid kind!");
    return (IsLittleEndian? InfosLE : InfosBE)[Kind - FirstTargetFixupKind];
  }

  void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
                  uint64_t Value, bool IsPCRel) const override {
    Value = adjustFixupValue(Fixup.getKind(), Value);
    if (!Value) return;           // Doesn't change encoding.

    unsigned Offset = Fixup.getOffset();
    unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());

    // For each byte of the fragment that the fixup touches, mask in the bits
    // from the fixup value. The Value has been "split up" into the appropriate
    // bitfields above.
    for (unsigned i = 0; i != NumBytes; ++i) {
      unsigned Idx = IsLittleEndian ? i : (NumBytes - 1 - i);
      Data[Offset + i] |= uint8_t((Value >> (Idx * 8)) & 0xff);
    }
  }

  void processFixupValue(const MCAssembler &Asm, const MCAsmLayout &Layout,
                         const MCFixup &Fixup, const MCFragment *DF,
                         const MCValue &Target, uint64_t &Value,
                         bool &IsResolved) override {
    switch ((PPC::Fixups)Fixup.getKind()) {
    default: break;
    case PPC::fixup_ppc_br24:
    case PPC::fixup_ppc_br24abs:
      // If the target symbol has a local entry point we must not attempt
      // to resolve the fixup directly.  Emit a relocation and leave
      // resolution of the final target address to the linker.
      if (const MCSymbolRefExpr *A = Target.getSymA()) {
        const MCSymbolData &Data = Asm.getSymbolData(A->getSymbol());
        // The "other" values are stored in the last 6 bits of the second byte.
        // The traditional defines for STO values assume the full byte and thus
        // the shift to pack it.
        unsigned Other = MCELF::getOther(Data) << 2;
        if ((Other & ELF::STO_PPC64_LOCAL_MASK) != 0)
          IsResolved = false;
      }
      break;
    }
  }

  bool mayNeedRelaxation(const MCInst &Inst) const override {
    // FIXME.
    return false;
  }

  bool fixupNeedsRelaxation(const MCFixup &Fixup,
                            uint64_t Value,
                            const MCRelaxableFragment *DF,
                            const MCAsmLayout &Layout) const override {
    // FIXME.
    llvm_unreachable("relaxInstruction() unimplemented");
  }


  void relaxInstruction(const MCInst &Inst, MCInst &Res) const override {
    // FIXME.
    llvm_unreachable("relaxInstruction() unimplemented");
  }

  bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override {
    uint64_t NumNops = Count / 4;
    for (uint64_t i = 0; i != NumNops; ++i)
      OW->Write32(0x60000000);

    switch (Count % 4) {
    default: break; // No leftover bytes to write
    case 1: OW->Write8(0); break;
    case 2: OW->Write16(0); break;
    case 3: OW->Write16(0); OW->Write8(0); break;
    }

    return true;
  }

  unsigned getPointerSize() const {
    StringRef Name = TheTarget.getName();
    if (Name == "ppc64" || Name == "ppc64le") return 8;
    assert(Name == "ppc32" && "Unknown target name!");
    return 4;
  }

  bool isLittleEndian() const {
    return IsLittleEndian;
  }
};
} // end anonymous namespace


// FIXME: This should be in a separate file.
namespace {
  class DarwinPPCAsmBackend : public PPCAsmBackend {
  public:
    DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T, false) { }

    MCObjectWriter *createObjectWriter(raw_ostream &OS) const override {
      bool is64 = getPointerSize() == 8;
      return createPPCMachObjectWriter(
          OS,
          /*Is64Bit=*/is64,
          (is64 ? MachO::CPU_TYPE_POWERPC64 : MachO::CPU_TYPE_POWERPC),
          MachO::CPU_SUBTYPE_POWERPC_ALL);
    }
  };

  class ELFPPCAsmBackend : public PPCAsmBackend {
    uint8_t OSABI;
  public:
    ELFPPCAsmBackend(const Target &T, bool IsLittleEndian, uint8_t OSABI) :
      PPCAsmBackend(T, IsLittleEndian), OSABI(OSABI) { }


    MCObjectWriter *createObjectWriter(raw_ostream &OS) const override {
      bool is64 = getPointerSize() == 8;
      return createPPCELFObjectWriter(OS, is64, isLittleEndian(), OSABI);
    }
  };

} // end anonymous namespace

MCAsmBackend *llvm::createPPCAsmBackend(const Target &T,
                                        const MCRegisterInfo &MRI,
                                        StringRef TT, StringRef CPU) {
  if (Triple(TT).isOSDarwin())
    return new DarwinPPCAsmBackend(T);

  uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS());
  bool IsLittleEndian = Triple(TT).getArch() == Triple::ppc64le;
  return new ELFPPCAsmBackend(T, IsLittleEndian, OSABI);
}