1//===-- Hexagon.cpp -------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "InputFiles.h"
10#include "Symbols.h"
11#include "SyntheticSections.h"
12#include "Target.h"
13#include "lld/Common/ErrorHandler.h"
14#include "llvm/BinaryFormat/ELF.h"
15#include "llvm/Object/ELF.h"
16#include "llvm/Support/Endian.h"
17
18using namespace llvm;
19using namespace llvm::object;
20using namespace llvm::support::endian;
21using namespace llvm::ELF;
22using namespace lld;
23using namespace lld::elf;
24
25namespace {
26class Hexagon final : public TargetInfo {
27public:
28  Hexagon();
29  uint32_t calcEFlags() const override;
30  RelExpr getRelExpr(RelType type, const Symbol &s,
31                     const uint8_t *loc) const override;
32  RelType getDynRel(RelType type) const override;
33  void relocate(uint8_t *loc, const Relocation &rel,
34                uint64_t val) const override;
35  void writePltHeader(uint8_t *buf) const override;
36  void writePlt(uint8_t *buf, const Symbol &sym,
37                uint64_t pltEntryAddr) const override;
38};
39} // namespace
40
41Hexagon::Hexagon() {
42  pltRel = R_HEX_JMP_SLOT;
43  relativeRel = R_HEX_RELATIVE;
44  gotRel = R_HEX_GLOB_DAT;
45  symbolicRel = R_HEX_32;
46
47  // The zero'th GOT entry is reserved for the address of _DYNAMIC.  The
48  // next 3 are reserved for the dynamic loader.
49  gotPltHeaderEntriesNum = 4;
50
51  pltEntrySize = 16;
52  pltHeaderSize = 32;
53
54  // Hexagon Linux uses 64K pages by default.
55  defaultMaxPageSize = 0x10000;
56  noneRel = R_HEX_NONE;
57  tlsGotRel = R_HEX_TPREL_32;
58  tlsModuleIndexRel = R_HEX_DTPMOD_32;
59  tlsOffsetRel = R_HEX_DTPREL_32;
60}
61
62uint32_t Hexagon::calcEFlags() const {
63  assert(!objectFiles.empty());
64
65  // The architecture revision must always be equal to or greater than
66  // greatest revision in the list of inputs.
67  uint32_t ret = 0;
68  for (InputFile *f : objectFiles) {
69    uint32_t eflags = cast<ObjFile<ELF32LE>>(f)->getObj().getHeader()->e_flags;
70    if (eflags > ret)
71      ret = eflags;
72  }
73  return ret;
74}
75
76static uint32_t applyMask(uint32_t mask, uint32_t data) {
77  uint32_t result = 0;
78  size_t off = 0;
79
80  for (size_t bit = 0; bit != 32; ++bit) {
81    uint32_t valBit = (data >> off) & 1;
82    uint32_t maskBit = (mask >> bit) & 1;
83    if (maskBit) {
84      result |= (valBit << bit);
85      ++off;
86    }
87  }
88  return result;
89}
90
91RelExpr Hexagon::getRelExpr(RelType type, const Symbol &s,
92                            const uint8_t *loc) const {
93  switch (type) {
94  case R_HEX_NONE:
95    return R_NONE;
96  case R_HEX_6_X:
97  case R_HEX_8_X:
98  case R_HEX_9_X:
99  case R_HEX_10_X:
100  case R_HEX_11_X:
101  case R_HEX_12_X:
102  case R_HEX_16_X:
103  case R_HEX_32:
104  case R_HEX_32_6_X:
105  case R_HEX_HI16:
106  case R_HEX_LO16:
107  case R_HEX_DTPREL_32:
108    return R_ABS;
109  case R_HEX_B9_PCREL:
110  case R_HEX_B13_PCREL:
111  case R_HEX_B15_PCREL:
112  case R_HEX_6_PCREL_X:
113  case R_HEX_32_PCREL:
114    return R_PC;
115  case R_HEX_B9_PCREL_X:
116  case R_HEX_B15_PCREL_X:
117  case R_HEX_B22_PCREL:
118  case R_HEX_PLT_B22_PCREL:
119  case R_HEX_B22_PCREL_X:
120  case R_HEX_B32_PCREL_X:
121  case R_HEX_GD_PLT_B22_PCREL:
122  case R_HEX_GD_PLT_B22_PCREL_X:
123  case R_HEX_GD_PLT_B32_PCREL_X:
124    return R_PLT_PC;
125  case R_HEX_IE_32_6_X:
126  case R_HEX_IE_16_X:
127  case R_HEX_IE_HI16:
128  case R_HEX_IE_LO16:
129    return R_GOT;
130  case R_HEX_GD_GOT_11_X:
131  case R_HEX_GD_GOT_16_X:
132  case R_HEX_GD_GOT_32_6_X:
133    return R_TLSGD_GOTPLT;
134  case R_HEX_GOTREL_11_X:
135  case R_HEX_GOTREL_16_X:
136  case R_HEX_GOTREL_32_6_X:
137  case R_HEX_GOTREL_HI16:
138  case R_HEX_GOTREL_LO16:
139    return R_GOTPLTREL;
140  case R_HEX_GOT_11_X:
141  case R_HEX_GOT_16_X:
142  case R_HEX_GOT_32_6_X:
143    return R_GOTPLT;
144  case R_HEX_IE_GOT_11_X:
145  case R_HEX_IE_GOT_16_X:
146  case R_HEX_IE_GOT_32_6_X:
147  case R_HEX_IE_GOT_HI16:
148  case R_HEX_IE_GOT_LO16:
149    config->hasStaticTlsModel = true;
150    return R_GOTPLT;
151  case R_HEX_TPREL_11_X:
152  case R_HEX_TPREL_16:
153  case R_HEX_TPREL_16_X:
154  case R_HEX_TPREL_32_6_X:
155  case R_HEX_TPREL_HI16:
156  case R_HEX_TPREL_LO16:
157    return R_TLS;
158  default:
159    error(getErrorLocation(loc) + "unknown relocation (" + Twine(type) +
160          ") against symbol " + toString(s));
161    return R_NONE;
162  }
163}
164
165static bool isDuplex(uint32_t insn) {
166  // Duplex forms have a fixed mask and parse bits 15:14 are always
167  // zero.  Non-duplex insns will always have at least one bit set in the
168  // parse field.
169  return (0xC000 & insn) == 0;
170}
171
172static uint32_t findMaskR6(uint32_t insn) {
173  // There are (arguably too) many relocation masks for the DSP's
174  // R_HEX_6_X type.  The table below is used to select the correct mask
175  // for the given instruction.
176  struct InstructionMask {
177    uint32_t cmpMask;
178    uint32_t relocMask;
179  };
180
181  static const InstructionMask r6[] = {
182      {0x38000000, 0x0000201f}, {0x39000000, 0x0000201f},
183      {0x3e000000, 0x00001f80}, {0x3f000000, 0x00001f80},
184      {0x40000000, 0x000020f8}, {0x41000000, 0x000007e0},
185      {0x42000000, 0x000020f8}, {0x43000000, 0x000007e0},
186      {0x44000000, 0x000020f8}, {0x45000000, 0x000007e0},
187      {0x46000000, 0x000020f8}, {0x47000000, 0x000007e0},
188      {0x6a000000, 0x00001f80}, {0x7c000000, 0x001f2000},
189      {0x9a000000, 0x00000f60}, {0x9b000000, 0x00000f60},
190      {0x9c000000, 0x00000f60}, {0x9d000000, 0x00000f60},
191      {0x9f000000, 0x001f0100}, {0xab000000, 0x0000003f},
192      {0xad000000, 0x0000003f}, {0xaf000000, 0x00030078},
193      {0xd7000000, 0x006020e0}, {0xd8000000, 0x006020e0},
194      {0xdb000000, 0x006020e0}, {0xdf000000, 0x006020e0}};
195
196  if (isDuplex(insn))
197    return 0x03f00000;
198
199  for (InstructionMask i : r6)
200    if ((0xff000000 & insn) == i.cmpMask)
201      return i.relocMask;
202
203  error("unrecognized instruction for R_HEX_6 relocation: 0x" +
204        utohexstr(insn));
205  return 0;
206}
207
208static uint32_t findMaskR8(uint32_t insn) {
209  if ((0xff000000 & insn) == 0xde000000)
210    return 0x00e020e8;
211  if ((0xff000000 & insn) == 0x3c000000)
212    return 0x0000207f;
213  return 0x00001fe0;
214}
215
216static uint32_t findMaskR11(uint32_t insn) {
217  if ((0xff000000 & insn) == 0xa1000000)
218    return 0x060020ff;
219  return 0x06003fe0;
220}
221
222static uint32_t findMaskR16(uint32_t insn) {
223  if ((0xff000000 & insn) == 0x48000000)
224    return 0x061f20ff;
225  if ((0xff000000 & insn) == 0x49000000)
226    return 0x061f3fe0;
227  if ((0xff000000 & insn) == 0x78000000)
228    return 0x00df3fe0;
229  if ((0xff000000 & insn) == 0xb0000000)
230    return 0x0fe03fe0;
231
232  if (isDuplex(insn))
233    return 0x03f00000;
234
235  error("unrecognized instruction for R_HEX_16_X relocation: 0x" +
236        utohexstr(insn));
237  return 0;
238}
239
240static void or32le(uint8_t *p, int32_t v) { write32le(p, read32le(p) | v); }
241
242void Hexagon::relocate(uint8_t *loc, const Relocation &rel,
243                       uint64_t val) const {
244  switch (rel.type) {
245  case R_HEX_NONE:
246    break;
247  case R_HEX_6_PCREL_X:
248  case R_HEX_6_X:
249    or32le(loc, applyMask(findMaskR6(read32le(loc)), val));
250    break;
251  case R_HEX_8_X:
252    or32le(loc, applyMask(findMaskR8(read32le(loc)), val));
253    break;
254  case R_HEX_9_X:
255    or32le(loc, applyMask(0x00003fe0, val & 0x3f));
256    break;
257  case R_HEX_10_X:
258    or32le(loc, applyMask(0x00203fe0, val & 0x3f));
259    break;
260  case R_HEX_11_X:
261  case R_HEX_GD_GOT_11_X:
262  case R_HEX_IE_GOT_11_X:
263  case R_HEX_GOT_11_X:
264  case R_HEX_GOTREL_11_X:
265  case R_HEX_TPREL_11_X:
266    or32le(loc, applyMask(findMaskR11(read32le(loc)), val & 0x3f));
267    break;
268  case R_HEX_12_X:
269    or32le(loc, applyMask(0x000007e0, val));
270    break;
271  case R_HEX_16_X: // These relocs only have 6 effective bits.
272  case R_HEX_IE_16_X:
273  case R_HEX_IE_GOT_16_X:
274  case R_HEX_GD_GOT_16_X:
275  case R_HEX_GOT_16_X:
276  case R_HEX_GOTREL_16_X:
277  case R_HEX_TPREL_16_X:
278    or32le(loc, applyMask(findMaskR16(read32le(loc)), val & 0x3f));
279    break;
280  case R_HEX_TPREL_16:
281    or32le(loc, applyMask(findMaskR16(read32le(loc)), val & 0xffff));
282    break;
283  case R_HEX_32:
284  case R_HEX_32_PCREL:
285  case R_HEX_DTPREL_32:
286    or32le(loc, val);
287    break;
288  case R_HEX_32_6_X:
289  case R_HEX_GD_GOT_32_6_X:
290  case R_HEX_GOT_32_6_X:
291  case R_HEX_GOTREL_32_6_X:
292  case R_HEX_IE_GOT_32_6_X:
293  case R_HEX_IE_32_6_X:
294  case R_HEX_TPREL_32_6_X:
295    or32le(loc, applyMask(0x0fff3fff, val >> 6));
296    break;
297  case R_HEX_B9_PCREL:
298    checkInt(loc, val, 11, rel);
299    or32le(loc, applyMask(0x003000fe, val >> 2));
300    break;
301  case R_HEX_B9_PCREL_X:
302    or32le(loc, applyMask(0x003000fe, val & 0x3f));
303    break;
304  case R_HEX_B13_PCREL:
305    checkInt(loc, val, 15, rel);
306    or32le(loc, applyMask(0x00202ffe, val >> 2));
307    break;
308  case R_HEX_B15_PCREL:
309    checkInt(loc, val, 17, rel);
310    or32le(loc, applyMask(0x00df20fe, val >> 2));
311    break;
312  case R_HEX_B15_PCREL_X:
313    or32le(loc, applyMask(0x00df20fe, val & 0x3f));
314    break;
315  case R_HEX_B22_PCREL:
316  case R_HEX_GD_PLT_B22_PCREL:
317  case R_HEX_PLT_B22_PCREL:
318    checkInt(loc, val, 22, rel);
319    or32le(loc, applyMask(0x1ff3ffe, val >> 2));
320    break;
321  case R_HEX_B22_PCREL_X:
322  case R_HEX_GD_PLT_B22_PCREL_X:
323    or32le(loc, applyMask(0x1ff3ffe, val & 0x3f));
324    break;
325  case R_HEX_B32_PCREL_X:
326  case R_HEX_GD_PLT_B32_PCREL_X:
327    or32le(loc, applyMask(0x0fff3fff, val >> 6));
328    break;
329  case R_HEX_GOTREL_HI16:
330  case R_HEX_HI16:
331  case R_HEX_IE_GOT_HI16:
332  case R_HEX_IE_HI16:
333  case R_HEX_TPREL_HI16:
334    or32le(loc, applyMask(0x00c03fff, val >> 16));
335    break;
336  case R_HEX_GOTREL_LO16:
337  case R_HEX_LO16:
338  case R_HEX_IE_GOT_LO16:
339  case R_HEX_IE_LO16:
340  case R_HEX_TPREL_LO16:
341    or32le(loc, applyMask(0x00c03fff, val));
342    break;
343  default:
344    llvm_unreachable("unknown relocation");
345  }
346}
347
348void Hexagon::writePltHeader(uint8_t *buf) const {
349  const uint8_t pltData[] = {
350      0x00, 0x40, 0x00, 0x00, // { immext (#0)
351      0x1c, 0xc0, 0x49, 0x6a, //   r28 = add (pc, ##GOT0@PCREL) } # @GOT0
352      0x0e, 0x42, 0x9c, 0xe2, // { r14 -= add (r28, #16)  # offset of GOTn
353      0x4f, 0x40, 0x9c, 0x91, //   r15 = memw (r28 + #8)  # object ID at GOT2
354      0x3c, 0xc0, 0x9c, 0x91, //   r28 = memw (r28 + #4) }# dynamic link at GOT1
355      0x0e, 0x42, 0x0e, 0x8c, // { r14 = asr (r14, #2)    # index of PLTn
356      0x00, 0xc0, 0x9c, 0x52, //   jumpr r28 }            # call dynamic linker
357      0x0c, 0xdb, 0x00, 0x54, // trap0(#0xdb) # bring plt0 into 16byte alignment
358  };
359  memcpy(buf, pltData, sizeof(pltData));
360
361  // Offset from PLT0 to the GOT.
362  uint64_t off = in.gotPlt->getVA() - in.plt->getVA();
363  relocateNoSym(buf, R_HEX_B32_PCREL_X, off);
364  relocateNoSym(buf + 4, R_HEX_6_PCREL_X, off);
365}
366
367void Hexagon::writePlt(uint8_t *buf, const Symbol &sym,
368                       uint64_t pltEntryAddr) const {
369  const uint8_t inst[] = {
370      0x00, 0x40, 0x00, 0x00, // { immext (#0)
371      0x0e, 0xc0, 0x49, 0x6a, //   r14 = add (pc, ##GOTn@PCREL) }
372      0x1c, 0xc0, 0x8e, 0x91, // r28 = memw (r14)
373      0x00, 0xc0, 0x9c, 0x52, // jumpr r28
374  };
375  memcpy(buf, inst, sizeof(inst));
376
377  uint64_t gotPltEntryAddr = sym.getGotPltVA();
378  relocateNoSym(buf, R_HEX_B32_PCREL_X, gotPltEntryAddr - pltEntryAddr);
379  relocateNoSym(buf + 4, R_HEX_6_PCREL_X, gotPltEntryAddr - pltEntryAddr);
380}
381
382RelType Hexagon::getDynRel(RelType type) const {
383  if (type == R_HEX_32)
384    return type;
385  return R_HEX_NONE;
386}
387
388TargetInfo *elf::getHexagonTargetInfo() {
389  static Hexagon target;
390  return &target;
391}
392