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1 //===-- X86MachObjectWriter.cpp - X86 Mach-O Writer -----------------------===//
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 #include "MCTargetDesc/X86FixupKinds.h"
11 #include "MCTargetDesc/X86MCTargetDesc.h"
12 #include "llvm/MC/MCAssembler.h"
13 #include "llvm/MC/MCAsmLayout.h"
14 #include "llvm/MC/MCMachObjectWriter.h"
15 #include "llvm/MC/MCSectionMachO.h"
16 #include "llvm/MC/MCValue.h"
17 #include "llvm/ADT/Twine.h"
18 #include "llvm/Support/ErrorHandling.h"
19 #include "llvm/Object/MachOFormat.h"
20 
21 using namespace llvm;
22 using namespace llvm::object;
23 
24 namespace {
25 class X86MachObjectWriter : public MCMachObjectTargetWriter {
26   void RecordScatteredRelocation(MachObjectWriter *Writer,
27                                  const MCAssembler &Asm,
28                                  const MCAsmLayout &Layout,
29                                  const MCFragment *Fragment,
30                                  const MCFixup &Fixup,
31                                  MCValue Target,
32                                  unsigned Log2Size,
33                                  uint64_t &FixedValue);
34   void RecordTLVPRelocation(MachObjectWriter *Writer,
35                             const MCAssembler &Asm,
36                             const MCAsmLayout &Layout,
37                             const MCFragment *Fragment,
38                             const MCFixup &Fixup,
39                             MCValue Target,
40                             uint64_t &FixedValue);
41 
42   void RecordX86Relocation(MachObjectWriter *Writer,
43                               const MCAssembler &Asm,
44                               const MCAsmLayout &Layout,
45                               const MCFragment *Fragment,
46                               const MCFixup &Fixup,
47                               MCValue Target,
48                               uint64_t &FixedValue);
49   void RecordX86_64Relocation(MachObjectWriter *Writer,
50                               const MCAssembler &Asm,
51                               const MCAsmLayout &Layout,
52                               const MCFragment *Fragment,
53                               const MCFixup &Fixup,
54                               MCValue Target,
55                               uint64_t &FixedValue);
56 public:
X86MachObjectWriter(bool Is64Bit,uint32_t CPUType,uint32_t CPUSubtype)57   X86MachObjectWriter(bool Is64Bit, uint32_t CPUType,
58                       uint32_t CPUSubtype)
59     : MCMachObjectTargetWriter(Is64Bit, CPUType, CPUSubtype,
60                                /*UseAggressiveSymbolFolding=*/Is64Bit) {}
61 
RecordRelocation(MachObjectWriter * Writer,const MCAssembler & Asm,const MCAsmLayout & Layout,const MCFragment * Fragment,const MCFixup & Fixup,MCValue Target,uint64_t & FixedValue)62   void RecordRelocation(MachObjectWriter *Writer,
63                         const MCAssembler &Asm, const MCAsmLayout &Layout,
64                         const MCFragment *Fragment, const MCFixup &Fixup,
65                         MCValue Target, uint64_t &FixedValue) {
66     if (Writer->is64Bit())
67       RecordX86_64Relocation(Writer, Asm, Layout, Fragment, Fixup, Target,
68                              FixedValue);
69     else
70       RecordX86Relocation(Writer, Asm, Layout, Fragment, Fixup, Target,
71                           FixedValue);
72   }
73 };
74 }
75 
isFixupKindRIPRel(unsigned Kind)76 static bool isFixupKindRIPRel(unsigned Kind) {
77   return Kind == X86::reloc_riprel_4byte ||
78     Kind == X86::reloc_riprel_4byte_movq_load;
79 }
80 
getFixupKindLog2Size(unsigned Kind)81 static unsigned getFixupKindLog2Size(unsigned Kind) {
82   switch (Kind) {
83   default:
84     llvm_unreachable("invalid fixup kind!");
85   case FK_PCRel_1:
86   case FK_Data_1: return 0;
87   case FK_PCRel_2:
88   case FK_Data_2: return 1;
89   case FK_PCRel_4:
90     // FIXME: Remove these!!!
91   case X86::reloc_riprel_4byte:
92   case X86::reloc_riprel_4byte_movq_load:
93   case X86::reloc_signed_4byte:
94   case FK_Data_4: return 2;
95   case FK_Data_8: return 3;
96   }
97 }
98 
RecordX86_64Relocation(MachObjectWriter * Writer,const MCAssembler & Asm,const MCAsmLayout & Layout,const MCFragment * Fragment,const MCFixup & Fixup,MCValue Target,uint64_t & FixedValue)99 void X86MachObjectWriter::RecordX86_64Relocation(MachObjectWriter *Writer,
100                                                  const MCAssembler &Asm,
101                                                  const MCAsmLayout &Layout,
102                                                  const MCFragment *Fragment,
103                                                  const MCFixup &Fixup,
104                                                  MCValue Target,
105                                                  uint64_t &FixedValue) {
106   unsigned IsPCRel = Writer->isFixupKindPCRel(Asm, Fixup.getKind());
107   unsigned IsRIPRel = isFixupKindRIPRel(Fixup.getKind());
108   unsigned Log2Size = getFixupKindLog2Size(Fixup.getKind());
109 
110   // See <reloc.h>.
111   uint32_t FixupOffset =
112     Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
113   uint32_t FixupAddress =
114     Writer->getFragmentAddress(Fragment, Layout) + Fixup.getOffset();
115   int64_t Value = 0;
116   unsigned Index = 0;
117   unsigned IsExtern = 0;
118   unsigned Type = 0;
119 
120   Value = Target.getConstant();
121 
122   if (IsPCRel) {
123     // Compensate for the relocation offset, Darwin x86_64 relocations only have
124     // the addend and appear to have attempted to define it to be the actual
125     // expression addend without the PCrel bias. However, instructions with data
126     // following the relocation are not accommodated for (see comment below
127     // regarding SIGNED{1,2,4}), so it isn't exactly that either.
128     Value += 1LL << Log2Size;
129   }
130 
131   if (Target.isAbsolute()) { // constant
132     // SymbolNum of 0 indicates the absolute section.
133     Type = macho::RIT_X86_64_Unsigned;
134     Index = 0;
135 
136     // FIXME: I believe this is broken, I don't think the linker can understand
137     // it. I think it would require a local relocation, but I'm not sure if that
138     // would work either. The official way to get an absolute PCrel relocation
139     // is to use an absolute symbol (which we don't support yet).
140     if (IsPCRel) {
141       IsExtern = 1;
142       Type = macho::RIT_X86_64_Branch;
143     }
144   } else if (Target.getSymB()) { // A - B + constant
145     const MCSymbol *A = &Target.getSymA()->getSymbol();
146     MCSymbolData &A_SD = Asm.getSymbolData(*A);
147     const MCSymbolData *A_Base = Asm.getAtom(&A_SD);
148 
149     const MCSymbol *B = &Target.getSymB()->getSymbol();
150     MCSymbolData &B_SD = Asm.getSymbolData(*B);
151     const MCSymbolData *B_Base = Asm.getAtom(&B_SD);
152 
153     // Neither symbol can be modified.
154     if (Target.getSymA()->getKind() != MCSymbolRefExpr::VK_None ||
155         Target.getSymB()->getKind() != MCSymbolRefExpr::VK_None)
156       report_fatal_error("unsupported relocation of modified symbol");
157 
158     // We don't support PCrel relocations of differences. Darwin 'as' doesn't
159     // implement most of these correctly.
160     if (IsPCRel)
161       report_fatal_error("unsupported pc-relative relocation of difference");
162 
163     // The support for the situation where one or both of the symbols would
164     // require a local relocation is handled just like if the symbols were
165     // external.  This is certainly used in the case of debug sections where the
166     // section has only temporary symbols and thus the symbols don't have base
167     // symbols.  This is encoded using the section ordinal and non-extern
168     // relocation entries.
169 
170     // Darwin 'as' doesn't emit correct relocations for this (it ends up with a
171     // single SIGNED relocation); reject it for now.  Except the case where both
172     // symbols don't have a base, equal but both NULL.
173     if (A_Base == B_Base && A_Base)
174       report_fatal_error("unsupported relocation with identical base");
175 
176     Value += Writer->getSymbolAddress(&A_SD, Layout) -
177       (A_Base == NULL ? 0 : Writer->getSymbolAddress(A_Base, Layout));
178     Value -= Writer->getSymbolAddress(&B_SD, Layout) -
179       (B_Base == NULL ? 0 : Writer->getSymbolAddress(B_Base, Layout));
180 
181     if (A_Base) {
182       Index = A_Base->getIndex();
183       IsExtern = 1;
184     }
185     else {
186       Index = A_SD.getFragment()->getParent()->getOrdinal() + 1;
187       IsExtern = 0;
188     }
189     Type = macho::RIT_X86_64_Unsigned;
190 
191     macho::RelocationEntry MRE;
192     MRE.Word0 = FixupOffset;
193     MRE.Word1 = ((Index     <<  0) |
194                  (IsPCRel   << 24) |
195                  (Log2Size  << 25) |
196                  (IsExtern  << 27) |
197                  (Type      << 28));
198     Writer->addRelocation(Fragment->getParent(), MRE);
199 
200     if (B_Base) {
201       Index = B_Base->getIndex();
202       IsExtern = 1;
203     }
204     else {
205       Index = B_SD.getFragment()->getParent()->getOrdinal() + 1;
206       IsExtern = 0;
207     }
208     Type = macho::RIT_X86_64_Subtractor;
209   } else {
210     const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
211     MCSymbolData &SD = Asm.getSymbolData(*Symbol);
212     const MCSymbolData *Base = Asm.getAtom(&SD);
213 
214     // Relocations inside debug sections always use local relocations when
215     // possible. This seems to be done because the debugger doesn't fully
216     // understand x86_64 relocation entries, and expects to find values that
217     // have already been fixed up.
218     if (Symbol->isInSection()) {
219       const MCSectionMachO &Section = static_cast<const MCSectionMachO&>(
220         Fragment->getParent()->getSection());
221       if (Section.hasAttribute(MCSectionMachO::S_ATTR_DEBUG))
222         Base = 0;
223     }
224 
225     // x86_64 almost always uses external relocations, except when there is no
226     // symbol to use as a base address (a local symbol with no preceding
227     // non-local symbol).
228     if (Base) {
229       Index = Base->getIndex();
230       IsExtern = 1;
231 
232       // Add the local offset, if needed.
233       if (Base != &SD)
234         Value += Layout.getSymbolOffset(&SD) - Layout.getSymbolOffset(Base);
235     } else if (Symbol->isInSection() && !Symbol->isVariable()) {
236       // The index is the section ordinal (1-based).
237       Index = SD.getFragment()->getParent()->getOrdinal() + 1;
238       IsExtern = 0;
239       Value += Writer->getSymbolAddress(&SD, Layout);
240 
241       if (IsPCRel)
242         Value -= FixupAddress + (1 << Log2Size);
243     } else if (Symbol->isVariable()) {
244       const MCExpr *Value = Symbol->getVariableValue();
245       int64_t Res;
246       bool isAbs = Value->EvaluateAsAbsolute(Res, Layout,
247                                              Writer->getSectionAddressMap());
248       if (isAbs) {
249         FixedValue = Res;
250         return;
251       } else {
252         report_fatal_error("unsupported relocation of variable '" +
253                            Symbol->getName() + "'");
254       }
255     } else {
256       report_fatal_error("unsupported relocation of undefined symbol '" +
257                          Symbol->getName() + "'");
258     }
259 
260     MCSymbolRefExpr::VariantKind Modifier = Target.getSymA()->getKind();
261     if (IsPCRel) {
262       if (IsRIPRel) {
263         if (Modifier == MCSymbolRefExpr::VK_GOTPCREL) {
264           // x86_64 distinguishes movq foo@GOTPCREL so that the linker can
265           // rewrite the movq to an leaq at link time if the symbol ends up in
266           // the same linkage unit.
267           if (unsigned(Fixup.getKind()) == X86::reloc_riprel_4byte_movq_load)
268             Type = macho::RIT_X86_64_GOTLoad;
269           else
270             Type = macho::RIT_X86_64_GOT;
271         }  else if (Modifier == MCSymbolRefExpr::VK_TLVP) {
272           Type = macho::RIT_X86_64_TLV;
273         }  else if (Modifier != MCSymbolRefExpr::VK_None) {
274           report_fatal_error("unsupported symbol modifier in relocation");
275         } else {
276           Type = macho::RIT_X86_64_Signed;
277 
278           // The Darwin x86_64 relocation format has a problem where it cannot
279           // encode an address (L<foo> + <constant>) which is outside the atom
280           // containing L<foo>. Generally, this shouldn't occur but it does
281           // happen when we have a RIPrel instruction with data following the
282           // relocation entry (e.g., movb $012, L0(%rip)). Even with the PCrel
283           // adjustment Darwin x86_64 uses, the offset is still negative and the
284           // linker has no way to recognize this.
285           //
286           // To work around this, Darwin uses several special relocation types
287           // to indicate the offsets. However, the specification or
288           // implementation of these seems to also be incomplete; they should
289           // adjust the addend as well based on the actual encoded instruction
290           // (the additional bias), but instead appear to just look at the final
291           // offset.
292           switch (-(Target.getConstant() + (1LL << Log2Size))) {
293           case 1: Type = macho::RIT_X86_64_Signed1; break;
294           case 2: Type = macho::RIT_X86_64_Signed2; break;
295           case 4: Type = macho::RIT_X86_64_Signed4; break;
296           }
297         }
298       } else {
299         if (Modifier != MCSymbolRefExpr::VK_None)
300           report_fatal_error("unsupported symbol modifier in branch "
301                              "relocation");
302 
303         Type = macho::RIT_X86_64_Branch;
304       }
305     } else {
306       if (Modifier == MCSymbolRefExpr::VK_GOT) {
307         Type = macho::RIT_X86_64_GOT;
308       } else if (Modifier == MCSymbolRefExpr::VK_GOTPCREL) {
309         // GOTPCREL is allowed as a modifier on non-PCrel instructions, in which
310         // case all we do is set the PCrel bit in the relocation entry; this is
311         // used with exception handling, for example. The source is required to
312         // include any necessary offset directly.
313         Type = macho::RIT_X86_64_GOT;
314         IsPCRel = 1;
315       } else if (Modifier == MCSymbolRefExpr::VK_TLVP) {
316         report_fatal_error("TLVP symbol modifier should have been rip-rel");
317       } else if (Modifier != MCSymbolRefExpr::VK_None)
318         report_fatal_error("unsupported symbol modifier in relocation");
319       else
320         Type = macho::RIT_X86_64_Unsigned;
321     }
322   }
323 
324   // x86_64 always writes custom values into the fixups.
325   FixedValue = Value;
326 
327   // struct relocation_info (8 bytes)
328   macho::RelocationEntry MRE;
329   MRE.Word0 = FixupOffset;
330   MRE.Word1 = ((Index     <<  0) |
331                (IsPCRel   << 24) |
332                (Log2Size  << 25) |
333                (IsExtern  << 27) |
334                (Type      << 28));
335   Writer->addRelocation(Fragment->getParent(), MRE);
336 }
337 
RecordScatteredRelocation(MachObjectWriter * Writer,const MCAssembler & Asm,const MCAsmLayout & Layout,const MCFragment * Fragment,const MCFixup & Fixup,MCValue Target,unsigned Log2Size,uint64_t & FixedValue)338 void X86MachObjectWriter::RecordScatteredRelocation(MachObjectWriter *Writer,
339                                                     const MCAssembler &Asm,
340                                                     const MCAsmLayout &Layout,
341                                                     const MCFragment *Fragment,
342                                                     const MCFixup &Fixup,
343                                                     MCValue Target,
344                                                     unsigned Log2Size,
345                                                     uint64_t &FixedValue) {
346   uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
347   unsigned IsPCRel = Writer->isFixupKindPCRel(Asm, Fixup.getKind());
348   unsigned Type = macho::RIT_Vanilla;
349 
350   // See <reloc.h>.
351   const MCSymbol *A = &Target.getSymA()->getSymbol();
352   MCSymbolData *A_SD = &Asm.getSymbolData(*A);
353 
354   if (!A_SD->getFragment())
355     report_fatal_error("symbol '" + A->getName() +
356                        "' can not be undefined in a subtraction expression");
357 
358   uint32_t Value = Writer->getSymbolAddress(A_SD, Layout);
359   uint64_t SecAddr = Writer->getSectionAddress(A_SD->getFragment()->getParent());
360   FixedValue += SecAddr;
361   uint32_t Value2 = 0;
362 
363   if (const MCSymbolRefExpr *B = Target.getSymB()) {
364     MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol());
365 
366     if (!B_SD->getFragment())
367       report_fatal_error("symbol '" + B->getSymbol().getName() +
368                          "' can not be undefined in a subtraction expression");
369 
370     // Select the appropriate difference relocation type.
371     //
372     // Note that there is no longer any semantic difference between these two
373     // relocation types from the linkers point of view, this is done solely for
374     // pedantic compatibility with 'as'.
375     Type = A_SD->isExternal() ? (unsigned)macho::RIT_Difference :
376       (unsigned)macho::RIT_Generic_LocalDifference;
377     Value2 = Writer->getSymbolAddress(B_SD, Layout);
378     FixedValue -= Writer->getSectionAddress(B_SD->getFragment()->getParent());
379   }
380 
381   // Relocations are written out in reverse order, so the PAIR comes first.
382   if (Type == macho::RIT_Difference ||
383       Type == macho::RIT_Generic_LocalDifference) {
384     macho::RelocationEntry MRE;
385     MRE.Word0 = ((0         <<  0) |
386                  (macho::RIT_Pair  << 24) |
387                  (Log2Size  << 28) |
388                  (IsPCRel   << 30) |
389                  macho::RF_Scattered);
390     MRE.Word1 = Value2;
391     Writer->addRelocation(Fragment->getParent(), MRE);
392   }
393 
394   macho::RelocationEntry MRE;
395   MRE.Word0 = ((FixupOffset <<  0) |
396                (Type        << 24) |
397                (Log2Size    << 28) |
398                (IsPCRel     << 30) |
399                macho::RF_Scattered);
400   MRE.Word1 = Value;
401   Writer->addRelocation(Fragment->getParent(), MRE);
402 }
403 
RecordTLVPRelocation(MachObjectWriter * Writer,const MCAssembler & Asm,const MCAsmLayout & Layout,const MCFragment * Fragment,const MCFixup & Fixup,MCValue Target,uint64_t & FixedValue)404 void X86MachObjectWriter::RecordTLVPRelocation(MachObjectWriter *Writer,
405                                                const MCAssembler &Asm,
406                                                const MCAsmLayout &Layout,
407                                                const MCFragment *Fragment,
408                                                const MCFixup &Fixup,
409                                                MCValue Target,
410                                                uint64_t &FixedValue) {
411   assert(Target.getSymA()->getKind() == MCSymbolRefExpr::VK_TLVP &&
412          !is64Bit() &&
413          "Should only be called with a 32-bit TLVP relocation!");
414 
415   unsigned Log2Size = getFixupKindLog2Size(Fixup.getKind());
416   uint32_t Value = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
417   unsigned IsPCRel = 0;
418 
419   // Get the symbol data.
420   MCSymbolData *SD_A = &Asm.getSymbolData(Target.getSymA()->getSymbol());
421   unsigned Index = SD_A->getIndex();
422 
423   // We're only going to have a second symbol in pic mode and it'll be a
424   // subtraction from the picbase. For 32-bit pic the addend is the difference
425   // between the picbase and the next address.  For 32-bit static the addend is
426   // zero.
427   if (Target.getSymB()) {
428     // If this is a subtraction then we're pcrel.
429     uint32_t FixupAddress =
430       Writer->getFragmentAddress(Fragment, Layout) + Fixup.getOffset();
431     MCSymbolData *SD_B = &Asm.getSymbolData(Target.getSymB()->getSymbol());
432     IsPCRel = 1;
433     FixedValue = (FixupAddress - Writer->getSymbolAddress(SD_B, Layout) +
434                   Target.getConstant());
435     FixedValue += 1ULL << Log2Size;
436   } else {
437     FixedValue = 0;
438   }
439 
440   // struct relocation_info (8 bytes)
441   macho::RelocationEntry MRE;
442   MRE.Word0 = Value;
443   MRE.Word1 = ((Index                  <<  0) |
444                (IsPCRel                << 24) |
445                (Log2Size               << 25) |
446                (1                      << 27) | // Extern
447                (macho::RIT_Generic_TLV << 28)); // Type
448   Writer->addRelocation(Fragment->getParent(), MRE);
449 }
450 
RecordX86Relocation(MachObjectWriter * Writer,const MCAssembler & Asm,const MCAsmLayout & Layout,const MCFragment * Fragment,const MCFixup & Fixup,MCValue Target,uint64_t & FixedValue)451 void X86MachObjectWriter::RecordX86Relocation(MachObjectWriter *Writer,
452                                               const MCAssembler &Asm,
453                                               const MCAsmLayout &Layout,
454                                               const MCFragment *Fragment,
455                                               const MCFixup &Fixup,
456                                               MCValue Target,
457                                               uint64_t &FixedValue) {
458   unsigned IsPCRel = Writer->isFixupKindPCRel(Asm, Fixup.getKind());
459   unsigned Log2Size = getFixupKindLog2Size(Fixup.getKind());
460 
461   // If this is a 32-bit TLVP reloc it's handled a bit differently.
462   if (Target.getSymA() &&
463       Target.getSymA()->getKind() == MCSymbolRefExpr::VK_TLVP) {
464     RecordTLVPRelocation(Writer, Asm, Layout, Fragment, Fixup, Target,
465                          FixedValue);
466     return;
467   }
468 
469   // If this is a difference or a defined symbol plus an offset, then we need a
470   // scattered relocation entry. Differences always require scattered
471   // relocations.
472   if (Target.getSymB())
473     return RecordScatteredRelocation(Writer, Asm, Layout, Fragment, Fixup,
474                                      Target, Log2Size, FixedValue);
475 
476   // Get the symbol data, if any.
477   MCSymbolData *SD = 0;
478   if (Target.getSymA())
479     SD = &Asm.getSymbolData(Target.getSymA()->getSymbol());
480 
481   // If this is an internal relocation with an offset, it also needs a scattered
482   // relocation entry.
483   uint32_t Offset = Target.getConstant();
484   if (IsPCRel)
485     Offset += 1 << Log2Size;
486   if (Offset && SD && !Writer->doesSymbolRequireExternRelocation(SD))
487     return RecordScatteredRelocation(Writer, Asm, Layout, Fragment, Fixup,
488                                      Target, Log2Size, FixedValue);
489 
490   // See <reloc.h>.
491   uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
492   unsigned Index = 0;
493   unsigned IsExtern = 0;
494   unsigned Type = 0;
495 
496   if (Target.isAbsolute()) { // constant
497     // SymbolNum of 0 indicates the absolute section.
498     //
499     // FIXME: Currently, these are never generated (see code below). I cannot
500     // find a case where they are actually emitted.
501     Type = macho::RIT_Vanilla;
502   } else {
503     // Resolve constant variables.
504     if (SD->getSymbol().isVariable()) {
505       int64_t Res;
506       if (SD->getSymbol().getVariableValue()->EvaluateAsAbsolute(
507             Res, Layout, Writer->getSectionAddressMap())) {
508         FixedValue = Res;
509         return;
510       }
511     }
512 
513     // Check whether we need an external or internal relocation.
514     if (Writer->doesSymbolRequireExternRelocation(SD)) {
515       IsExtern = 1;
516       Index = SD->getIndex();
517       // For external relocations, make sure to offset the fixup value to
518       // compensate for the addend of the symbol address, if it was
519       // undefined. This occurs with weak definitions, for example.
520       if (!SD->Symbol->isUndefined())
521         FixedValue -= Layout.getSymbolOffset(SD);
522     } else {
523       // The index is the section ordinal (1-based).
524       const MCSectionData &SymSD = Asm.getSectionData(
525         SD->getSymbol().getSection());
526       Index = SymSD.getOrdinal() + 1;
527       FixedValue += Writer->getSectionAddress(&SymSD);
528     }
529     if (IsPCRel)
530       FixedValue -= Writer->getSectionAddress(Fragment->getParent());
531 
532     Type = macho::RIT_Vanilla;
533   }
534 
535   // struct relocation_info (8 bytes)
536   macho::RelocationEntry MRE;
537   MRE.Word0 = FixupOffset;
538   MRE.Word1 = ((Index     <<  0) |
539                (IsPCRel   << 24) |
540                (Log2Size  << 25) |
541                (IsExtern  << 27) |
542                (Type      << 28));
543   Writer->addRelocation(Fragment->getParent(), MRE);
544 }
545 
createX86MachObjectWriter(raw_ostream & OS,bool Is64Bit,uint32_t CPUType,uint32_t CPUSubtype)546 MCObjectWriter *llvm::createX86MachObjectWriter(raw_ostream &OS,
547                                                 bool Is64Bit,
548                                                 uint32_t CPUType,
549                                                 uint32_t CPUSubtype) {
550   return createMachObjectWriter(new X86MachObjectWriter(Is64Bit,
551                                                         CPUType,
552                                                         CPUSubtype),
553                                 OS, /*IsLittleEndian=*/true);
554 }
555