7888a838ad9cefbfe28d2fb70e48ad1cc0f43cf2
[oota-llvm.git] / lib / CodeGen / TargetLoweringObjectFileImpl.cpp
1 //===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===//
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 implements classes used to handle lowerings specific to common
11 // object file formats.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Function.h"
19 #include "llvm/GlobalVariable.h"
20 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCSectionMachO.h"
24 #include "llvm/MC/MCSectionELF.h"
25 #include "llvm/MC/MCSectionCOFF.h"
26 #include "llvm/MC/MCStreamer.h"
27 #include "llvm/MC/MCSymbol.h"
28 #include "llvm/Target/Mangler.h"
29 #include "llvm/Target/TargetData.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/Target/TargetOptions.h"
32 #include "llvm/Support/Dwarf.h"
33 #include "llvm/Support/ELF.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/ADT/SmallString.h"
37 #include "llvm/ADT/StringExtras.h"
38 #include "llvm/ADT/Triple.h"
39 using namespace llvm;
40 using namespace dwarf;
41
42 //===----------------------------------------------------------------------===//
43 //                                  ELF
44 //===----------------------------------------------------------------------===//
45
46 void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
47                                              const TargetMachine &TM) {
48   TargetLoweringObjectFile::Initialize(Ctx, TM);
49
50   BSSSection =
51     getContext().getELFSection(".bss", ELF::SHT_NOBITS,
52                                ELF::SHF_WRITE |ELF::SHF_ALLOC,
53                                SectionKind::getBSS());
54
55   TextSection =
56     getContext().getELFSection(".text", ELF::SHT_PROGBITS,
57                                ELF::SHF_EXECINSTR |
58                                ELF::SHF_ALLOC,
59                                SectionKind::getText());
60
61   DataSection =
62     getContext().getELFSection(".data", ELF::SHT_PROGBITS,
63                                ELF::SHF_WRITE |ELF::SHF_ALLOC,
64                                SectionKind::getDataRel());
65
66   ReadOnlySection =
67     getContext().getELFSection(".rodata", ELF::SHT_PROGBITS,
68                                ELF::SHF_ALLOC,
69                                SectionKind::getReadOnly());
70
71   TLSDataSection =
72     getContext().getELFSection(".tdata", ELF::SHT_PROGBITS,
73                                ELF::SHF_ALLOC | ELF::SHF_TLS |
74                                ELF::SHF_WRITE,
75                                SectionKind::getThreadData());
76
77   TLSBSSSection =
78     getContext().getELFSection(".tbss", ELF::SHT_NOBITS,
79                                ELF::SHF_ALLOC | ELF::SHF_TLS |
80                                ELF::SHF_WRITE,
81                                SectionKind::getThreadBSS());
82
83   DataRelSection =
84     getContext().getELFSection(".data.rel", ELF::SHT_PROGBITS,
85                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
86                                SectionKind::getDataRel());
87
88   DataRelLocalSection =
89     getContext().getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
90                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
91                                SectionKind::getDataRelLocal());
92
93   DataRelROSection =
94     getContext().getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
95                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
96                                SectionKind::getReadOnlyWithRel());
97
98   DataRelROLocalSection =
99     getContext().getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
100                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
101                                SectionKind::getReadOnlyWithRelLocal());
102
103   MergeableConst4Section =
104     getContext().getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
105                                ELF::SHF_ALLOC |ELF::SHF_MERGE,
106                                SectionKind::getMergeableConst4());
107
108   MergeableConst8Section =
109     getContext().getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
110                                ELF::SHF_ALLOC |ELF::SHF_MERGE,
111                                SectionKind::getMergeableConst8());
112
113   MergeableConst16Section =
114     getContext().getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
115                                ELF::SHF_ALLOC |ELF::SHF_MERGE,
116                                SectionKind::getMergeableConst16());
117
118   StaticCtorSection =
119     getContext().getELFSection(".ctors", ELF::SHT_PROGBITS,
120                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
121                                SectionKind::getDataRel());
122
123   StaticDtorSection =
124     getContext().getELFSection(".dtors", ELF::SHT_PROGBITS,
125                                ELF::SHF_ALLOC |ELF::SHF_WRITE,
126                                SectionKind::getDataRel());
127
128   // Exception Handling Sections.
129
130   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
131   // it contains relocatable pointers.  In PIC mode, this is probably a big
132   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
133   // adjusted or this should be a data section.
134   LSDASection =
135     getContext().getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
136                                ELF::SHF_ALLOC,
137                                SectionKind::getReadOnly());
138   // Debug Info Sections.
139   DwarfAbbrevSection =
140     getContext().getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
141                                SectionKind::getMetadata());
142   DwarfInfoSection =
143     getContext().getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
144                                SectionKind::getMetadata());
145   DwarfLineSection =
146     getContext().getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
147                                SectionKind::getMetadata());
148   DwarfFrameSection =
149     getContext().getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
150                                SectionKind::getMetadata());
151   DwarfPubNamesSection =
152     getContext().getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
153                                SectionKind::getMetadata());
154   DwarfPubTypesSection =
155     getContext().getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
156                                SectionKind::getMetadata());
157   DwarfStrSection =
158     getContext().getELFSection(".debug_str", ELF::SHT_PROGBITS, 0,
159                                SectionKind::getMetadata());
160   DwarfLocSection =
161     getContext().getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
162                                SectionKind::getMetadata());
163   DwarfARangesSection =
164     getContext().getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
165                                SectionKind::getMetadata());
166   DwarfRangesSection =
167     getContext().getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
168                                SectionKind::getMetadata());
169   DwarfMacroInfoSection =
170     getContext().getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
171                                SectionKind::getMetadata());
172 }
173
174 const MCSection *TargetLoweringObjectFileELF::getEHFrameSection() const {
175   return getContext().getELFSection(".eh_frame", ELF::SHT_PROGBITS,
176                                     ELF::SHF_ALLOC,
177                                     SectionKind::getDataRel());
178 }
179
180 MCSymbol *
181 TargetLoweringObjectFileELF::getPersonalityPICSymbol(StringRef Name) const {
182   Twine FullName = StringRef("DW.ref.") + Name;
183   return getContext().GetOrCreateSymbol(FullName);
184 }
185
186 void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
187                                                        const TargetMachine &TM,
188                                                    const MCSymbol *Sym) const {
189   MCSymbol *Label = getPersonalityPICSymbol(Sym->getName());
190   Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
191   Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
192   Twine SectionName = StringRef(".data.") + Label->getName();
193   SmallString<64> NameData;
194   SectionName.toVector(NameData);
195   unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
196   const MCSection *Sec = getContext().getELFSection(NameData,
197                                                     ELF::SHT_PROGBITS,
198                                                     Flags,
199                                                     SectionKind::getDataRel(),
200                                                     0, Label->getName());
201   Streamer.SwitchSection(Sec);
202   Streamer.EmitValueToAlignment(8);
203   Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
204   const MCExpr *E = MCConstantExpr::Create(8, getContext());
205   Streamer.EmitELFSize(Label, E);
206   Streamer.EmitLabel(Label);
207
208   unsigned Size = TM.getTargetData()->getPointerSize();
209   Streamer.EmitSymbolValue(Sym, Size);
210 }
211
212 static SectionKind
213 getELFKindForNamedSection(StringRef Name, SectionKind K) {
214   // FIXME: Why is this here? Codegen is should not be in the business
215   // of figuring section flags. If the user wrote section(".eh_frame"),
216   // we should just pass that to MC which will defer to the assembly
217   // or use its default if producing an object file.
218   if (Name.empty() || Name[0] != '.') return K;
219
220   // Some lame default implementation based on some magic section names.
221   if (Name == ".bss" ||
222       Name.startswith(".bss.") ||
223       Name.startswith(".gnu.linkonce.b.") ||
224       Name.startswith(".llvm.linkonce.b.") ||
225       Name == ".sbss" ||
226       Name.startswith(".sbss.") ||
227       Name.startswith(".gnu.linkonce.sb.") ||
228       Name.startswith(".llvm.linkonce.sb."))
229     return SectionKind::getBSS();
230
231   if (Name == ".tdata" ||
232       Name.startswith(".tdata.") ||
233       Name.startswith(".gnu.linkonce.td.") ||
234       Name.startswith(".llvm.linkonce.td."))
235     return SectionKind::getThreadData();
236
237   if (Name == ".tbss" ||
238       Name.startswith(".tbss.") ||
239       Name.startswith(".gnu.linkonce.tb.") ||
240       Name.startswith(".llvm.linkonce.tb."))
241     return SectionKind::getThreadBSS();
242
243   if (Name == ".eh_frame")
244     return SectionKind::getDataRel();
245
246   return K;
247 }
248
249
250 static unsigned getELFSectionType(StringRef Name, SectionKind K) {
251
252   if (Name == ".init_array")
253     return ELF::SHT_INIT_ARRAY;
254
255   if (Name == ".fini_array")
256     return ELF::SHT_FINI_ARRAY;
257
258   if (Name == ".preinit_array")
259     return ELF::SHT_PREINIT_ARRAY;
260
261   if (K.isBSS() || K.isThreadBSS())
262     return ELF::SHT_NOBITS;
263
264   return ELF::SHT_PROGBITS;
265 }
266
267
268 static unsigned
269 getELFSectionFlags(SectionKind K) {
270   unsigned Flags = 0;
271
272   if (!K.isMetadata())
273     Flags |= ELF::SHF_ALLOC;
274
275   if (K.isText())
276     Flags |= ELF::SHF_EXECINSTR;
277
278   if (K.isWriteable())
279     Flags |= ELF::SHF_WRITE;
280
281   if (K.isThreadLocal())
282     Flags |= ELF::SHF_TLS;
283
284   // K.isMergeableConst() is left out to honour PR4650
285   if (K.isMergeableCString() || K.isMergeableConst4() ||
286       K.isMergeableConst8() || K.isMergeableConst16())
287     Flags |= ELF::SHF_MERGE;
288
289   if (K.isMergeableCString())
290     Flags |= ELF::SHF_STRINGS;
291
292   return Flags;
293 }
294
295
296 const MCSection *TargetLoweringObjectFileELF::
297 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
298                          Mangler *Mang, const TargetMachine &TM) const {
299   StringRef SectionName = GV->getSection();
300
301   // Infer section flags from the section name if we can.
302   Kind = getELFKindForNamedSection(SectionName, Kind);
303
304   return getContext().getELFSection(SectionName,
305                                     getELFSectionType(SectionName, Kind),
306                                     getELFSectionFlags(Kind), Kind);
307 }
308
309 /// getSectionPrefixForGlobal - Return the section prefix name used by options
310 /// FunctionsSections and DataSections.
311 static const char *getSectionPrefixForGlobal(SectionKind Kind) {
312   if (Kind.isText())                 return ".text.";
313   if (Kind.isReadOnly())             return ".rodata.";
314
315   if (Kind.isThreadData())           return ".tdata.";
316   if (Kind.isThreadBSS())            return ".tbss.";
317
318   if (Kind.isDataNoRel())            return ".data.";
319   if (Kind.isDataRelLocal())         return ".data.rel.local.";
320   if (Kind.isDataRel())              return ".data.rel.";
321   if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
322
323   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
324   return ".data.rel.ro.";
325 }
326
327
328 const MCSection *TargetLoweringObjectFileELF::
329 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
330                        Mangler *Mang, const TargetMachine &TM) const {
331   // If we have -ffunction-section or -fdata-section then we should emit the
332   // global value to a uniqued section specifically for it.
333   bool EmitUniquedSection;
334   if (Kind.isText())
335     EmitUniquedSection = TM.getFunctionSections();
336   else
337     EmitUniquedSection = TM.getDataSections();
338
339   // If this global is linkonce/weak and the target handles this by emitting it
340   // into a 'uniqued' section name, create and return the section now.
341   if ((GV->isWeakForLinker() || EmitUniquedSection) &&
342       !Kind.isCommon() && !Kind.isBSS()) {
343     const char *Prefix;
344     Prefix = getSectionPrefixForGlobal(Kind);
345
346     SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
347     MCSymbol *Sym = Mang->getSymbol(GV);
348     Name.append(Sym->getName().begin(), Sym->getName().end());
349     StringRef Group = "";
350     unsigned Flags = getELFSectionFlags(Kind);
351     if (GV->isWeakForLinker()) {
352       Group = Sym->getName();
353       Flags |= ELF::SHF_GROUP;
354     }
355
356     return getContext().getELFSection(Name.str(),
357                                       getELFSectionType(Name.str(), Kind),
358                                       Flags, Kind, 0, Group);
359   }
360
361   if (Kind.isText()) return TextSection;
362
363   if (Kind.isMergeable1ByteCString() ||
364       Kind.isMergeable2ByteCString() ||
365       Kind.isMergeable4ByteCString()) {
366
367     // We also need alignment here.
368     // FIXME: this is getting the alignment of the character, not the
369     // alignment of the global!
370     unsigned Align =
371       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
372
373     const char *SizeSpec = ".rodata.str1.";
374     if (Kind.isMergeable2ByteCString())
375       SizeSpec = ".rodata.str2.";
376     else if (Kind.isMergeable4ByteCString())
377       SizeSpec = ".rodata.str4.";
378     else
379       assert(Kind.isMergeable1ByteCString() && "unknown string width");
380
381
382     std::string Name = SizeSpec + utostr(Align);
383     return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
384                                       ELF::SHF_ALLOC |
385                                       ELF::SHF_MERGE |
386                                       ELF::SHF_STRINGS,
387                                       Kind);
388   }
389
390   if (Kind.isMergeableConst()) {
391     if (Kind.isMergeableConst4() && MergeableConst4Section)
392       return MergeableConst4Section;
393     if (Kind.isMergeableConst8() && MergeableConst8Section)
394       return MergeableConst8Section;
395     if (Kind.isMergeableConst16() && MergeableConst16Section)
396       return MergeableConst16Section;
397     return ReadOnlySection;  // .const
398   }
399
400   if (Kind.isReadOnly())             return ReadOnlySection;
401
402   if (Kind.isThreadData())           return TLSDataSection;
403   if (Kind.isThreadBSS())            return TLSBSSSection;
404
405   // Note: we claim that common symbols are put in BSSSection, but they are
406   // really emitted with the magic .comm directive, which creates a symbol table
407   // entry but not a section.
408   if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
409
410   if (Kind.isDataNoRel())            return DataSection;
411   if (Kind.isDataRelLocal())         return DataRelLocalSection;
412   if (Kind.isDataRel())              return DataRelSection;
413   if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
414
415   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
416   return DataRelROSection;
417 }
418
419 /// getSectionForConstant - Given a mergeable constant with the
420 /// specified size and relocation information, return a section that it
421 /// should be placed in.
422 const MCSection *TargetLoweringObjectFileELF::
423 getSectionForConstant(SectionKind Kind) const {
424   if (Kind.isMergeableConst4() && MergeableConst4Section)
425     return MergeableConst4Section;
426   if (Kind.isMergeableConst8() && MergeableConst8Section)
427     return MergeableConst8Section;
428   if (Kind.isMergeableConst16() && MergeableConst16Section)
429     return MergeableConst16Section;
430   if (Kind.isReadOnly())
431     return ReadOnlySection;
432
433   if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
434   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
435   return DataRelROSection;
436 }
437
438 const MCExpr *TargetLoweringObjectFileELF::
439 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
440                                MachineModuleInfo *MMI,
441                                unsigned Encoding, MCStreamer &Streamer) const {
442
443   if (Encoding & dwarf::DW_EH_PE_indirect) {
444     MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
445
446     SmallString<128> Name;
447     Mang->getNameWithPrefix(Name, GV, true);
448     Name += ".DW.stub";
449
450     // Add information about the stub reference to ELFMMI so that the stub
451     // gets emitted by the asmprinter.
452     MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
453     MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
454     if (StubSym.getPointer() == 0) {
455       MCSymbol *Sym = Mang->getSymbol(GV);
456       StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
457     }
458
459     return TargetLoweringObjectFile::
460       getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
461   }
462
463   return TargetLoweringObjectFile::
464     getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
465 }
466
467 //===----------------------------------------------------------------------===//
468 //                                 MachO
469 //===----------------------------------------------------------------------===//
470
471 void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
472                                                const TargetMachine &TM) {
473   // _foo.eh symbols are currently always exported so that the linker knows
474   // about them.  This is not necessary on 10.6 and later, but it
475   // doesn't hurt anything.
476   // FIXME: I need to get this from Triple.
477   IsFunctionEHSymbolGlobal = true;
478   IsFunctionEHFrameSymbolPrivate = false;
479   SupportsWeakOmittedEHFrame = false;
480
481   // .comm doesn't support alignment before Leopard.
482   Triple T(((LLVMTargetMachine&)TM).getTargetTriple());
483   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
484     CommDirectiveSupportsAlignment = false;
485
486   TargetLoweringObjectFile::Initialize(Ctx, TM);
487
488   TextSection // .text
489     = getContext().getMachOSection("__TEXT", "__text",
490                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
491                                    SectionKind::getText());
492   DataSection // .data
493     = getContext().getMachOSection("__DATA", "__data", 0,
494                                    SectionKind::getDataRel());
495
496   TLSDataSection // .tdata
497     = getContext().getMachOSection("__DATA", "__thread_data",
498                                    MCSectionMachO::S_THREAD_LOCAL_REGULAR,
499                                    SectionKind::getDataRel());
500   TLSBSSSection // .tbss
501     = getContext().getMachOSection("__DATA", "__thread_bss",
502                                    MCSectionMachO::S_THREAD_LOCAL_ZEROFILL,
503                                    SectionKind::getThreadBSS());
504
505   // TODO: Verify datarel below.
506   TLSTLVSection // .tlv
507     = getContext().getMachOSection("__DATA", "__thread_vars",
508                                    MCSectionMachO::S_THREAD_LOCAL_VARIABLES,
509                                    SectionKind::getDataRel());
510
511   TLSThreadInitSection
512     = getContext().getMachOSection("__DATA", "__thread_init",
513                           MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
514                           SectionKind::getDataRel());
515
516   CStringSection // .cstring
517     = getContext().getMachOSection("__TEXT", "__cstring",
518                                    MCSectionMachO::S_CSTRING_LITERALS,
519                                    SectionKind::getMergeable1ByteCString());
520   UStringSection
521     = getContext().getMachOSection("__TEXT","__ustring", 0,
522                                    SectionKind::getMergeable2ByteCString());
523   FourByteConstantSection // .literal4
524     = getContext().getMachOSection("__TEXT", "__literal4",
525                                    MCSectionMachO::S_4BYTE_LITERALS,
526                                    SectionKind::getMergeableConst4());
527   EightByteConstantSection // .literal8
528     = getContext().getMachOSection("__TEXT", "__literal8",
529                                    MCSectionMachO::S_8BYTE_LITERALS,
530                                    SectionKind::getMergeableConst8());
531
532   // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
533   // to using it in -static mode.
534   SixteenByteConstantSection = 0;
535   if (TM.getRelocationModel() != Reloc::Static &&
536       TM.getTargetData()->getPointerSize() == 32)
537     SixteenByteConstantSection =   // .literal16
538       getContext().getMachOSection("__TEXT", "__literal16",
539                                    MCSectionMachO::S_16BYTE_LITERALS,
540                                    SectionKind::getMergeableConst16());
541
542   ReadOnlySection  // .const
543     = getContext().getMachOSection("__TEXT", "__const", 0,
544                                    SectionKind::getReadOnly());
545
546   TextCoalSection
547     = getContext().getMachOSection("__TEXT", "__textcoal_nt",
548                                    MCSectionMachO::S_COALESCED |
549                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
550                                    SectionKind::getText());
551   ConstTextCoalSection
552     = getContext().getMachOSection("__TEXT", "__const_coal",
553                                    MCSectionMachO::S_COALESCED,
554                                    SectionKind::getReadOnly());
555   ConstDataSection  // .const_data
556     = getContext().getMachOSection("__DATA", "__const", 0,
557                                    SectionKind::getReadOnlyWithRel());
558   DataCoalSection
559     = getContext().getMachOSection("__DATA","__datacoal_nt",
560                                    MCSectionMachO::S_COALESCED,
561                                    SectionKind::getDataRel());
562   DataCommonSection
563     = getContext().getMachOSection("__DATA","__common",
564                                    MCSectionMachO::S_ZEROFILL,
565                                    SectionKind::getBSS());
566   DataBSSSection
567     = getContext().getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL,
568                                    SectionKind::getBSS());
569
570
571   LazySymbolPointerSection
572     = getContext().getMachOSection("__DATA", "__la_symbol_ptr",
573                                    MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
574                                    SectionKind::getMetadata());
575   NonLazySymbolPointerSection
576     = getContext().getMachOSection("__DATA", "__nl_symbol_ptr",
577                                    MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
578                                    SectionKind::getMetadata());
579
580   if (TM.getRelocationModel() == Reloc::Static) {
581     StaticCtorSection
582       = getContext().getMachOSection("__TEXT", "__constructor", 0,
583                                      SectionKind::getDataRel());
584     StaticDtorSection
585       = getContext().getMachOSection("__TEXT", "__destructor", 0,
586                                      SectionKind::getDataRel());
587   } else {
588     StaticCtorSection
589       = getContext().getMachOSection("__DATA", "__mod_init_func",
590                                      MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
591                                      SectionKind::getDataRel());
592     StaticDtorSection
593       = getContext().getMachOSection("__DATA", "__mod_term_func",
594                                      MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
595                                      SectionKind::getDataRel());
596   }
597
598   // Exception Handling.
599   LSDASection = getContext().getMachOSection("__TEXT", "__gcc_except_tab", 0,
600                                              SectionKind::getReadOnlyWithRel());
601   // Debug Information.
602   DwarfAbbrevSection =
603     getContext().getMachOSection("__DWARF", "__debug_abbrev",
604                                  MCSectionMachO::S_ATTR_DEBUG,
605                                  SectionKind::getMetadata());
606   DwarfInfoSection =
607     getContext().getMachOSection("__DWARF", "__debug_info",
608                                  MCSectionMachO::S_ATTR_DEBUG,
609                                  SectionKind::getMetadata());
610   DwarfLineSection =
611     getContext().getMachOSection("__DWARF", "__debug_line",
612                                  MCSectionMachO::S_ATTR_DEBUG,
613                                  SectionKind::getMetadata());
614   DwarfFrameSection =
615     getContext().getMachOSection("__DWARF", "__debug_frame",
616                                  MCSectionMachO::S_ATTR_DEBUG,
617                                  SectionKind::getMetadata());
618   DwarfPubNamesSection =
619     getContext().getMachOSection("__DWARF", "__debug_pubnames",
620                                  MCSectionMachO::S_ATTR_DEBUG,
621                                  SectionKind::getMetadata());
622   DwarfPubTypesSection =
623     getContext().getMachOSection("__DWARF", "__debug_pubtypes",
624                                  MCSectionMachO::S_ATTR_DEBUG,
625                                  SectionKind::getMetadata());
626   DwarfStrSection =
627     getContext().getMachOSection("__DWARF", "__debug_str",
628                                  MCSectionMachO::S_ATTR_DEBUG,
629                                  SectionKind::getMetadata());
630   DwarfLocSection =
631     getContext().getMachOSection("__DWARF", "__debug_loc",
632                                  MCSectionMachO::S_ATTR_DEBUG,
633                                  SectionKind::getMetadata());
634   DwarfARangesSection =
635     getContext().getMachOSection("__DWARF", "__debug_aranges",
636                                  MCSectionMachO::S_ATTR_DEBUG,
637                                  SectionKind::getMetadata());
638   DwarfRangesSection =
639     getContext().getMachOSection("__DWARF", "__debug_ranges",
640                                  MCSectionMachO::S_ATTR_DEBUG,
641                                  SectionKind::getMetadata());
642   DwarfMacroInfoSection =
643     getContext().getMachOSection("__DWARF", "__debug_macinfo",
644                                  MCSectionMachO::S_ATTR_DEBUG,
645                                  SectionKind::getMetadata());
646   DwarfDebugInlineSection =
647     getContext().getMachOSection("__DWARF", "__debug_inlined",
648                                  MCSectionMachO::S_ATTR_DEBUG,
649                                  SectionKind::getMetadata());
650
651   TLSExtraDataSection = TLSTLVSection;
652 }
653
654 const MCSection *TargetLoweringObjectFileMachO::getEHFrameSection() const {
655   return getContext().getMachOSection("__TEXT", "__eh_frame",
656                                       MCSectionMachO::S_COALESCED |
657                                       MCSectionMachO::S_ATTR_NO_TOC |
658                                       MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
659                                       MCSectionMachO::S_ATTR_LIVE_SUPPORT,
660                                       SectionKind::getReadOnly());
661 }
662
663 const MCSection *TargetLoweringObjectFileMachO::
664 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
665                          Mangler *Mang, const TargetMachine &TM) const {
666   // Parse the section specifier and create it if valid.
667   StringRef Segment, Section;
668   unsigned TAA = 0, StubSize = 0;
669   bool TAAParsed;
670   std::string ErrorCode =
671     MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
672                                           TAA, TAAParsed, StubSize);
673   if (!ErrorCode.empty()) {
674     // If invalid, report the error with report_fatal_error.
675     report_fatal_error("Global variable '" + GV->getNameStr() +
676                       "' has an invalid section specifier '" + GV->getSection()+
677                       "': " + ErrorCode + ".");
678     // Fall back to dropping it into the data section.
679     return DataSection;
680   }
681
682   // Get the section.
683   const MCSectionMachO *S =
684     getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
685
686   // If TAA wasn't set by ParseSectionSpecifier() above,
687   // use the value returned by getMachOSection() as a default.
688   if (!TAAParsed)
689     TAA = S->getTypeAndAttributes();
690
691   // Okay, now that we got the section, verify that the TAA & StubSize agree.
692   // If the user declared multiple globals with different section flags, we need
693   // to reject it here.
694   if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
695     // If invalid, report the error with report_fatal_error.
696     report_fatal_error("Global variable '" + GV->getNameStr() +
697                       "' section type or attributes does not match previous"
698                       " section specifier");
699   }
700
701   return S;
702 }
703
704 const MCSection *TargetLoweringObjectFileMachO::
705 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
706                        Mangler *Mang, const TargetMachine &TM) const {
707
708   // Handle thread local data.
709   if (Kind.isThreadBSS()) return TLSBSSSection;
710   if (Kind.isThreadData()) return TLSDataSection;
711
712   if (Kind.isText())
713     return GV->isWeakForLinker() ? TextCoalSection : TextSection;
714
715   // If this is weak/linkonce, put this in a coalescable section, either in text
716   // or data depending on if it is writable.
717   if (GV->isWeakForLinker()) {
718     if (Kind.isReadOnly())
719       return ConstTextCoalSection;
720     return DataCoalSection;
721   }
722
723   // FIXME: Alignment check should be handled by section classifier.
724   if (Kind.isMergeable1ByteCString() &&
725       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
726     return CStringSection;
727
728   // Do not put 16-bit arrays in the UString section if they have an
729   // externally visible label, this runs into issues with certain linker
730   // versions.
731   if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
732       TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
733     return UStringSection;
734
735   if (Kind.isMergeableConst()) {
736     if (Kind.isMergeableConst4())
737       return FourByteConstantSection;
738     if (Kind.isMergeableConst8())
739       return EightByteConstantSection;
740     if (Kind.isMergeableConst16() && SixteenByteConstantSection)
741       return SixteenByteConstantSection;
742   }
743
744   // Otherwise, if it is readonly, but not something we can specially optimize,
745   // just drop it in .const.
746   if (Kind.isReadOnly())
747     return ReadOnlySection;
748
749   // If this is marked const, put it into a const section.  But if the dynamic
750   // linker needs to write to it, put it in the data segment.
751   if (Kind.isReadOnlyWithRel())
752     return ConstDataSection;
753
754   // Put zero initialized globals with strong external linkage in the
755   // DATA, __common section with the .zerofill directive.
756   if (Kind.isBSSExtern())
757     return DataCommonSection;
758
759   // Put zero initialized globals with local linkage in __DATA,__bss directive
760   // with the .zerofill directive (aka .lcomm).
761   if (Kind.isBSSLocal())
762     return DataBSSSection;
763
764   // Otherwise, just drop the variable in the normal data section.
765   return DataSection;
766 }
767
768 const MCSection *
769 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
770   // If this constant requires a relocation, we have to put it in the data
771   // segment, not in the text segment.
772   if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
773     return ConstDataSection;
774
775   if (Kind.isMergeableConst4())
776     return FourByteConstantSection;
777   if (Kind.isMergeableConst8())
778     return EightByteConstantSection;
779   if (Kind.isMergeableConst16() && SixteenByteConstantSection)
780     return SixteenByteConstantSection;
781   return ReadOnlySection;  // .const
782 }
783
784 /// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
785 /// not to emit the UsedDirective for some symbols in llvm.used.
786 // FIXME: REMOVE this (rdar://7071300)
787 bool TargetLoweringObjectFileMachO::
788 shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
789   /// On Darwin, internally linked data beginning with "L" or "l" does not have
790   /// the directive emitted (this occurs in ObjC metadata).
791   if (!GV) return false;
792
793   // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
794   if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
795     // FIXME: ObjC metadata is currently emitted as internal symbols that have
796     // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
797     // this horrible hack can go away.
798     MCSymbol *Sym = Mang->getSymbol(GV);
799     if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
800       return false;
801   }
802
803   return true;
804 }
805
806 const MCExpr *TargetLoweringObjectFileMachO::
807 getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
808                                MachineModuleInfo *MMI, unsigned Encoding,
809                                MCStreamer &Streamer) const {
810   // The mach-o version of this method defaults to returning a stub reference.
811
812   if (Encoding & DW_EH_PE_indirect) {
813     MachineModuleInfoMachO &MachOMMI =
814       MMI->getObjFileInfo<MachineModuleInfoMachO>();
815
816     SmallString<128> Name;
817     Mang->getNameWithPrefix(Name, GV, true);
818     Name += "$non_lazy_ptr";
819
820     // Add information about the stub reference to MachOMMI so that the stub
821     // gets emitted by the asmprinter.
822     MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
823     MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
824     if (StubSym.getPointer() == 0) {
825       MCSymbol *Sym = Mang->getSymbol(GV);
826       StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
827     }
828
829     return TargetLoweringObjectFile::
830       getExprForDwarfReference(SSym, Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
831   }
832
833   return TargetLoweringObjectFile::
834     getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
835 }
836
837 unsigned TargetLoweringObjectFileMachO::getPersonalityEncoding() const {
838   return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
839 }
840
841 unsigned TargetLoweringObjectFileMachO::getLSDAEncoding() const {
842   return DW_EH_PE_pcrel;
843 }
844
845 unsigned TargetLoweringObjectFileMachO::getFDEEncoding() const {
846   return DW_EH_PE_pcrel;
847 }
848
849 unsigned TargetLoweringObjectFileMachO::getTTypeEncoding() const {
850   return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
851 }
852
853 //===----------------------------------------------------------------------===//
854 //                                  COFF
855 //===----------------------------------------------------------------------===//
856
857 void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
858                                               const TargetMachine &TM) {
859   TargetLoweringObjectFile::Initialize(Ctx, TM);
860   TextSection =
861     getContext().getCOFFSection(".text",
862                                 COFF::IMAGE_SCN_CNT_CODE |
863                                 COFF::IMAGE_SCN_MEM_EXECUTE |
864                                 COFF::IMAGE_SCN_MEM_READ,
865                                 SectionKind::getText());
866   DataSection =
867     getContext().getCOFFSection(".data",
868                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
869                                 COFF::IMAGE_SCN_MEM_READ |
870                                 COFF::IMAGE_SCN_MEM_WRITE,
871                                 SectionKind::getDataRel());
872   ReadOnlySection =
873     getContext().getCOFFSection(".rdata",
874                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
875                                 COFF::IMAGE_SCN_MEM_READ,
876                                 SectionKind::getReadOnly());
877   StaticCtorSection =
878     getContext().getCOFFSection(".ctors",
879                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
880                                 COFF::IMAGE_SCN_MEM_READ |
881                                 COFF::IMAGE_SCN_MEM_WRITE,
882                                 SectionKind::getDataRel());
883   StaticDtorSection =
884     getContext().getCOFFSection(".dtors",
885                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
886                                 COFF::IMAGE_SCN_MEM_READ |
887                                 COFF::IMAGE_SCN_MEM_WRITE,
888                                 SectionKind::getDataRel());
889
890   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
891   // though it contains relocatable pointers.  In PIC mode, this is probably a
892   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
893   // adjusted or this should be a data section.
894   LSDASection =
895     getContext().getCOFFSection(".gcc_except_table",
896                                 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
897                                 COFF::IMAGE_SCN_MEM_READ,
898                                 SectionKind::getReadOnly());
899   // Debug info.
900   DwarfAbbrevSection =
901     getContext().getCOFFSection(".debug_abbrev",
902                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
903                                 COFF::IMAGE_SCN_MEM_READ,
904                                 SectionKind::getMetadata());
905   DwarfInfoSection =
906     getContext().getCOFFSection(".debug_info",
907                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
908                                 COFF::IMAGE_SCN_MEM_READ,
909                                 SectionKind::getMetadata());
910   DwarfLineSection =
911     getContext().getCOFFSection(".debug_line",
912                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
913                                 COFF::IMAGE_SCN_MEM_READ,
914                                 SectionKind::getMetadata());
915   DwarfFrameSection =
916     getContext().getCOFFSection(".debug_frame",
917                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
918                                 COFF::IMAGE_SCN_MEM_READ,
919                                 SectionKind::getMetadata());
920   DwarfPubNamesSection =
921     getContext().getCOFFSection(".debug_pubnames",
922                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
923                                 COFF::IMAGE_SCN_MEM_READ,
924                                 SectionKind::getMetadata());
925   DwarfPubTypesSection =
926     getContext().getCOFFSection(".debug_pubtypes",
927                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
928                                 COFF::IMAGE_SCN_MEM_READ,
929                                 SectionKind::getMetadata());
930   DwarfStrSection =
931     getContext().getCOFFSection(".debug_str",
932                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
933                                 COFF::IMAGE_SCN_MEM_READ,
934                                 SectionKind::getMetadata());
935   DwarfLocSection =
936     getContext().getCOFFSection(".debug_loc",
937                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
938                                 COFF::IMAGE_SCN_MEM_READ,
939                                 SectionKind::getMetadata());
940   DwarfARangesSection =
941     getContext().getCOFFSection(".debug_aranges",
942                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
943                                 COFF::IMAGE_SCN_MEM_READ,
944                                 SectionKind::getMetadata());
945   DwarfRangesSection =
946     getContext().getCOFFSection(".debug_ranges",
947                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
948                                 COFF::IMAGE_SCN_MEM_READ,
949                                 SectionKind::getMetadata());
950   DwarfMacroInfoSection =
951     getContext().getCOFFSection(".debug_macinfo",
952                                 COFF::IMAGE_SCN_MEM_DISCARDABLE |
953                                 COFF::IMAGE_SCN_MEM_READ,
954                                 SectionKind::getMetadata());
955
956   DrectveSection =
957     getContext().getCOFFSection(".drectve",
958                                 COFF::IMAGE_SCN_LNK_INFO,
959                                 SectionKind::getMetadata());
960 }
961
962 const MCSection *TargetLoweringObjectFileCOFF::getEHFrameSection() const {
963   return getContext().getCOFFSection(".eh_frame",
964                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
965                                      COFF::IMAGE_SCN_MEM_READ |
966                                      COFF::IMAGE_SCN_MEM_WRITE,
967                                      SectionKind::getDataRel());
968 }
969
970
971 static unsigned
972 getCOFFSectionFlags(SectionKind K) {
973   unsigned Flags = 0;
974
975   if (K.isMetadata())
976     Flags |=
977       COFF::IMAGE_SCN_MEM_DISCARDABLE;
978   else if (K.isText())
979     Flags |=
980       COFF::IMAGE_SCN_MEM_EXECUTE |
981       COFF::IMAGE_SCN_MEM_READ |
982       COFF::IMAGE_SCN_CNT_CODE;
983   else if (K.isBSS ())
984     Flags |=
985       COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
986       COFF::IMAGE_SCN_MEM_READ |
987       COFF::IMAGE_SCN_MEM_WRITE;
988   else if (K.isReadOnly())
989     Flags |=
990       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
991       COFF::IMAGE_SCN_MEM_READ;
992   else if (K.isWriteable())
993     Flags |=
994       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
995       COFF::IMAGE_SCN_MEM_READ |
996       COFF::IMAGE_SCN_MEM_WRITE;
997
998   return Flags;
999 }
1000
1001 const MCSection *TargetLoweringObjectFileCOFF::
1002 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
1003                          Mangler *Mang, const TargetMachine &TM) const {
1004   return getContext().getCOFFSection(GV->getSection(),
1005                                      getCOFFSectionFlags(Kind),
1006                                      Kind);
1007 }
1008
1009 static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
1010   if (Kind.isText())
1011     return ".text$";
1012   if (Kind.isBSS ())
1013     return ".bss$";
1014   if (Kind.isWriteable())
1015     return ".data$";
1016   return ".rdata$";
1017 }
1018
1019
1020 const MCSection *TargetLoweringObjectFileCOFF::
1021 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
1022                        Mangler *Mang, const TargetMachine &TM) const {
1023   assert(!Kind.isThreadLocal() && "Doesn't support TLS");
1024
1025   // If this global is linkonce/weak and the target handles this by emitting it
1026   // into a 'uniqued' section name, create and return the section now.
1027   if (GV->isWeakForLinker()) {
1028     const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
1029     SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
1030     MCSymbol *Sym = Mang->getSymbol(GV);
1031     Name.append(Sym->getName().begin() + 1, Sym->getName().end());
1032
1033     unsigned Characteristics = getCOFFSectionFlags(Kind);
1034
1035     Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
1036
1037     return getContext().getCOFFSection(Name.str(), Characteristics,
1038                           COFF::IMAGE_COMDAT_SELECT_ANY, Kind);
1039   }
1040
1041   if (Kind.isText())
1042     return getTextSection();
1043
1044   return getDataSection();
1045 }
1046