1 //===--- lib/CodeGen/DIE.cpp - DWARF Info Entries -------------------------===//
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 // Data structures for DWARF info entries.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/CodeGen/DIE.h"
14 #include "DwarfCompileUnit.h"
15 #include "DwarfDebug.h"
16 #include "DwarfUnit.h"
17 #include "llvm/ADT/Twine.h"
18 #include "llvm/CodeGen/AsmPrinter.h"
19 #include "llvm/Config/llvm-config.h"
20 #include "llvm/IR/DataLayout.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCStreamer.h"
24 #include "llvm/MC/MCSymbol.h"
25 #include "llvm/Support/Debug.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/Format.h"
28 #include "llvm/Support/FormattedStream.h"
29 #include "llvm/Support/LEB128.h"
30 #include "llvm/Support/MD5.h"
31 #include "llvm/Support/raw_ostream.h"
32 using namespace llvm;
33 
34 #define DEBUG_TYPE "dwarfdebug"
35 
36 //===----------------------------------------------------------------------===//
37 // DIEAbbrevData Implementation
38 //===----------------------------------------------------------------------===//
39 
40 /// Profile - Used to gather unique data for the abbreviation folding set.
41 ///
42 void DIEAbbrevData::Profile(FoldingSetNodeID &ID) const {
43   // Explicitly cast to an integer type for which FoldingSetNodeID has
44   // overloads.  Otherwise MSVC 2010 thinks this call is ambiguous.
45   ID.AddInteger(unsigned(Attribute));
46   ID.AddInteger(unsigned(Form));
47   if (Form == dwarf::DW_FORM_implicit_const)
48     ID.AddInteger(Value);
49 }
50 
51 //===----------------------------------------------------------------------===//
52 // DIEAbbrev Implementation
53 //===----------------------------------------------------------------------===//
54 
55 /// Profile - Used to gather unique data for the abbreviation folding set.
56 ///
57 void DIEAbbrev::Profile(FoldingSetNodeID &ID) const {
58   ID.AddInteger(unsigned(Tag));
59   ID.AddInteger(unsigned(Children));
60 
61   // For each attribute description.
62   for (unsigned i = 0, N = Data.size(); i < N; ++i)
63     Data[i].Profile(ID);
64 }
65 
66 /// Emit - Print the abbreviation using the specified asm printer.
67 ///
68 void DIEAbbrev::Emit(const AsmPrinter *AP) const {
69   // Emit its Dwarf tag type.
70   AP->emitULEB128(Tag, dwarf::TagString(Tag).data());
71 
72   // Emit whether it has children DIEs.
73   AP->emitULEB128((unsigned)Children, dwarf::ChildrenString(Children).data());
74 
75   // For each attribute description.
76   for (unsigned i = 0, N = Data.size(); i < N; ++i) {
77     const DIEAbbrevData &AttrData = Data[i];
78 
79     // Emit attribute type.
80     AP->emitULEB128(AttrData.getAttribute(),
81                     dwarf::AttributeString(AttrData.getAttribute()).data());
82 
83     // Emit form type.
84 #ifndef NDEBUG
85     // Could be an assertion, but this way we can see the failing form code
86     // easily, which helps track down where it came from.
87     if (!dwarf::isValidFormForVersion(AttrData.getForm(),
88                                       AP->getDwarfVersion())) {
89       LLVM_DEBUG(dbgs() << "Invalid form " << format("0x%x", AttrData.getForm())
90                         << " for DWARF version " << AP->getDwarfVersion()
91                         << "\n");
92       llvm_unreachable("Invalid form for specified DWARF version");
93     }
94 #endif
95     AP->emitULEB128(AttrData.getForm(),
96                     dwarf::FormEncodingString(AttrData.getForm()).data());
97 
98     // Emit value for DW_FORM_implicit_const.
99     if (AttrData.getForm() == dwarf::DW_FORM_implicit_const)
100       AP->emitSLEB128(AttrData.getValue());
101   }
102 
103   // Mark end of abbreviation.
104   AP->emitULEB128(0, "EOM(1)");
105   AP->emitULEB128(0, "EOM(2)");
106 }
107 
108 LLVM_DUMP_METHOD
109 void DIEAbbrev::print(raw_ostream &O) const {
110   O << "Abbreviation @"
111     << format("0x%lx", (long)(intptr_t)this)
112     << "  "
113     << dwarf::TagString(Tag)
114     << " "
115     << dwarf::ChildrenString(Children)
116     << '\n';
117 
118   for (unsigned i = 0, N = Data.size(); i < N; ++i) {
119     O << "  "
120       << dwarf::AttributeString(Data[i].getAttribute())
121       << "  "
122       << dwarf::FormEncodingString(Data[i].getForm());
123 
124     if (Data[i].getForm() == dwarf::DW_FORM_implicit_const)
125       O << " " << Data[i].getValue();
126 
127     O << '\n';
128   }
129 }
130 
131 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
132 LLVM_DUMP_METHOD void DIEAbbrev::dump() const {
133   print(dbgs());
134 }
135 #endif
136 
137 //===----------------------------------------------------------------------===//
138 // DIEAbbrevSet Implementation
139 //===----------------------------------------------------------------------===//
140 
141 DIEAbbrevSet::~DIEAbbrevSet() {
142   for (DIEAbbrev *Abbrev : Abbreviations)
143     Abbrev->~DIEAbbrev();
144 }
145 
146 DIEAbbrev &DIEAbbrevSet::uniqueAbbreviation(DIE &Die) {
147 
148   FoldingSetNodeID ID;
149   DIEAbbrev Abbrev = Die.generateAbbrev();
150   Abbrev.Profile(ID);
151 
152   void *InsertPos;
153   if (DIEAbbrev *Existing =
154           AbbreviationsSet.FindNodeOrInsertPos(ID, InsertPos)) {
155     Die.setAbbrevNumber(Existing->getNumber());
156     return *Existing;
157   }
158 
159   // Move the abbreviation to the heap and assign a number.
160   DIEAbbrev *New = new (Alloc) DIEAbbrev(std::move(Abbrev));
161   Abbreviations.push_back(New);
162   New->setNumber(Abbreviations.size());
163   Die.setAbbrevNumber(Abbreviations.size());
164 
165   // Store it for lookup.
166   AbbreviationsSet.InsertNode(New, InsertPos);
167   return *New;
168 }
169 
170 void DIEAbbrevSet::Emit(const AsmPrinter *AP, MCSection *Section) const {
171   if (!Abbreviations.empty()) {
172     // Start the debug abbrev section.
173     AP->OutStreamer->SwitchSection(Section);
174     AP->emitDwarfAbbrevs(Abbreviations);
175   }
176 }
177 
178 //===----------------------------------------------------------------------===//
179 // DIE Implementation
180 //===----------------------------------------------------------------------===//
181 
182 DIE *DIE::getParent() const {
183   return Owner.dyn_cast<DIE*>();
184 }
185 
186 DIEAbbrev DIE::generateAbbrev() const {
187   DIEAbbrev Abbrev(Tag, hasChildren());
188   for (const DIEValue &V : values())
189     if (V.getForm() == dwarf::DW_FORM_implicit_const)
190       Abbrev.AddImplicitConstAttribute(V.getAttribute(),
191                                        V.getDIEInteger().getValue());
192     else
193       Abbrev.AddAttribute(V.getAttribute(), V.getForm());
194   return Abbrev;
195 }
196 
197 unsigned DIE::getDebugSectionOffset() const {
198   const DIEUnit *Unit = getUnit();
199   assert(Unit && "DIE must be owned by a DIEUnit to get its absolute offset");
200   return Unit->getDebugSectionOffset() + getOffset();
201 }
202 
203 const DIE *DIE::getUnitDie() const {
204   const DIE *p = this;
205   while (p) {
206     if (p->getTag() == dwarf::DW_TAG_compile_unit ||
207         p->getTag() == dwarf::DW_TAG_type_unit)
208       return p;
209     p = p->getParent();
210   }
211   return nullptr;
212 }
213 
214 DIEUnit *DIE::getUnit() const {
215   const DIE *UnitDie = getUnitDie();
216   if (UnitDie)
217     return UnitDie->Owner.dyn_cast<DIEUnit*>();
218   return nullptr;
219 }
220 
221 DIEValue DIE::findAttribute(dwarf::Attribute Attribute) const {
222   // Iterate through all the attributes until we find the one we're
223   // looking for, if we can't find it return NULL.
224   for (const auto &V : values())
225     if (V.getAttribute() == Attribute)
226       return V;
227   return DIEValue();
228 }
229 
230 LLVM_DUMP_METHOD
231 static void printValues(raw_ostream &O, const DIEValueList &Values,
232                         StringRef Type, unsigned Size, unsigned IndentCount) {
233   O << Type << ": Size: " << Size << "\n";
234 
235   unsigned I = 0;
236   const std::string Indent(IndentCount, ' ');
237   for (const auto &V : Values.values()) {
238     O << Indent;
239     O << "Blk[" << I++ << "]";
240     O << "  " << dwarf::FormEncodingString(V.getForm()) << " ";
241     V.print(O);
242     O << "\n";
243   }
244 }
245 
246 LLVM_DUMP_METHOD
247 void DIE::print(raw_ostream &O, unsigned IndentCount) const {
248   const std::string Indent(IndentCount, ' ');
249   O << Indent << "Die: " << format("0x%lx", (long)(intptr_t) this)
250     << ", Offset: " << Offset << ", Size: " << Size << "\n";
251 
252   O << Indent << dwarf::TagString(getTag()) << " "
253     << dwarf::ChildrenString(hasChildren()) << "\n";
254 
255   IndentCount += 2;
256   for (const auto &V : values()) {
257     O << Indent;
258     O << dwarf::AttributeString(V.getAttribute());
259     O << "  " << dwarf::FormEncodingString(V.getForm()) << " ";
260     V.print(O);
261     O << "\n";
262   }
263   IndentCount -= 2;
264 
265   for (const auto &Child : children())
266     Child.print(O, IndentCount + 4);
267 
268   O << "\n";
269 }
270 
271 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
272 LLVM_DUMP_METHOD void DIE::dump() const {
273   print(dbgs());
274 }
275 #endif
276 
277 unsigned DIE::computeOffsetsAndAbbrevs(const AsmPrinter *AP,
278                                        DIEAbbrevSet &AbbrevSet,
279                                        unsigned CUOffset) {
280   // Unique the abbreviation and fill in the abbreviation number so this DIE
281   // can be emitted.
282   const DIEAbbrev &Abbrev = AbbrevSet.uniqueAbbreviation(*this);
283 
284   // Set compile/type unit relative offset of this DIE.
285   setOffset(CUOffset);
286 
287   // Add the byte size of the abbreviation code.
288   CUOffset += getULEB128Size(getAbbrevNumber());
289 
290   // Add the byte size of all the DIE attribute values.
291   for (const auto &V : values())
292     CUOffset += V.SizeOf(AP);
293 
294   // Let the children compute their offsets and abbreviation numbers.
295   if (hasChildren()) {
296     (void)Abbrev;
297     assert(Abbrev.hasChildren() && "Children flag not set");
298 
299     for (auto &Child : children())
300       CUOffset = Child.computeOffsetsAndAbbrevs(AP, AbbrevSet, CUOffset);
301 
302     // Each child chain is terminated with a zero byte, adjust the offset.
303     CUOffset += sizeof(int8_t);
304   }
305 
306   // Compute the byte size of this DIE and all of its children correctly. This
307   // is needed so that top level DIE can help the compile unit set its length
308   // correctly.
309   setSize(CUOffset - getOffset());
310   return CUOffset;
311 }
312 
313 //===----------------------------------------------------------------------===//
314 // DIEUnit Implementation
315 //===----------------------------------------------------------------------===//
316 DIEUnit::DIEUnit(uint16_t V, uint8_t A, dwarf::Tag UnitTag)
317     : Die(UnitTag), Section(nullptr), Offset(0), Length(0), Version(V),
318       AddrSize(A)
319 {
320   Die.Owner = this;
321   assert((UnitTag == dwarf::DW_TAG_compile_unit ||
322           UnitTag == dwarf::DW_TAG_skeleton_unit ||
323           UnitTag == dwarf::DW_TAG_type_unit ||
324           UnitTag == dwarf::DW_TAG_partial_unit) &&
325          "expected a unit TAG");
326 }
327 
328 void DIEValue::emitValue(const AsmPrinter *AP) const {
329   switch (Ty) {
330   case isNone:
331     llvm_unreachable("Expected valid DIEValue");
332 #define HANDLE_DIEVALUE(T)                                                     \
333   case is##T:                                                                  \
334     getDIE##T().emitValue(AP, Form);                                           \
335     break;
336 #include "llvm/CodeGen/DIEValue.def"
337   }
338 }
339 
340 unsigned DIEValue::SizeOf(const AsmPrinter *AP) const {
341   switch (Ty) {
342   case isNone:
343     llvm_unreachable("Expected valid DIEValue");
344 #define HANDLE_DIEVALUE(T)                                                     \
345   case is##T:                                                                  \
346     return getDIE##T().SizeOf(AP, Form);
347 #include "llvm/CodeGen/DIEValue.def"
348   }
349   llvm_unreachable("Unknown DIE kind");
350 }
351 
352 LLVM_DUMP_METHOD
353 void DIEValue::print(raw_ostream &O) const {
354   switch (Ty) {
355   case isNone:
356     llvm_unreachable("Expected valid DIEValue");
357 #define HANDLE_DIEVALUE(T)                                                     \
358   case is##T:                                                                  \
359     getDIE##T().print(O);                                                      \
360     break;
361 #include "llvm/CodeGen/DIEValue.def"
362   }
363 }
364 
365 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
366 LLVM_DUMP_METHOD void DIEValue::dump() const {
367   print(dbgs());
368 }
369 #endif
370 
371 //===----------------------------------------------------------------------===//
372 // DIEInteger Implementation
373 //===----------------------------------------------------------------------===//
374 
375 /// EmitValue - Emit integer of appropriate size.
376 ///
377 void DIEInteger::emitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
378   switch (Form) {
379   case dwarf::DW_FORM_implicit_const:
380   case dwarf::DW_FORM_flag_present:
381     // Emit something to keep the lines and comments in sync.
382     // FIXME: Is there a better way to do this?
383     Asm->OutStreamer->AddBlankLine();
384     return;
385   case dwarf::DW_FORM_flag:
386   case dwarf::DW_FORM_ref1:
387   case dwarf::DW_FORM_data1:
388   case dwarf::DW_FORM_strx1:
389   case dwarf::DW_FORM_addrx1:
390   case dwarf::DW_FORM_ref2:
391   case dwarf::DW_FORM_data2:
392   case dwarf::DW_FORM_strx2:
393   case dwarf::DW_FORM_addrx2:
394   case dwarf::DW_FORM_strx3:
395   case dwarf::DW_FORM_strp:
396   case dwarf::DW_FORM_ref4:
397   case dwarf::DW_FORM_data4:
398   case dwarf::DW_FORM_ref_sup4:
399   case dwarf::DW_FORM_strx4:
400   case dwarf::DW_FORM_addrx4:
401   case dwarf::DW_FORM_ref8:
402   case dwarf::DW_FORM_ref_sig8:
403   case dwarf::DW_FORM_data8:
404   case dwarf::DW_FORM_ref_sup8:
405   case dwarf::DW_FORM_GNU_ref_alt:
406   case dwarf::DW_FORM_GNU_strp_alt:
407   case dwarf::DW_FORM_line_strp:
408   case dwarf::DW_FORM_sec_offset:
409   case dwarf::DW_FORM_strp_sup:
410   case dwarf::DW_FORM_addr:
411   case dwarf::DW_FORM_ref_addr:
412     Asm->OutStreamer->emitIntValue(Integer, SizeOf(Asm, Form));
413     return;
414   case dwarf::DW_FORM_GNU_str_index:
415   case dwarf::DW_FORM_GNU_addr_index:
416   case dwarf::DW_FORM_ref_udata:
417   case dwarf::DW_FORM_strx:
418   case dwarf::DW_FORM_addrx:
419   case dwarf::DW_FORM_rnglistx:
420   case dwarf::DW_FORM_udata:
421     Asm->emitULEB128(Integer);
422     return;
423   case dwarf::DW_FORM_sdata:
424     Asm->emitSLEB128(Integer);
425     return;
426   default: llvm_unreachable("DIE Value form not supported yet");
427   }
428 }
429 
430 /// SizeOf - Determine size of integer value in bytes.
431 ///
432 unsigned DIEInteger::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
433   dwarf::FormParams Params = {0, 0, dwarf::DWARF32};
434   if (AP)
435     Params = {AP->getDwarfVersion(), uint8_t(AP->getPointerSize()),
436               AP->OutStreamer->getContext().getDwarfFormat()};
437 
438   if (Optional<uint8_t> FixedSize = dwarf::getFixedFormByteSize(Form, Params))
439     return *FixedSize;
440 
441   switch (Form) {
442   case dwarf::DW_FORM_GNU_str_index:
443   case dwarf::DW_FORM_GNU_addr_index:
444   case dwarf::DW_FORM_ref_udata:
445   case dwarf::DW_FORM_strx:
446   case dwarf::DW_FORM_addrx:
447   case dwarf::DW_FORM_rnglistx:
448   case dwarf::DW_FORM_udata:
449     return getULEB128Size(Integer);
450   case dwarf::DW_FORM_sdata:
451     return getSLEB128Size(Integer);
452   default: llvm_unreachable("DIE Value form not supported yet");
453   }
454 }
455 
456 LLVM_DUMP_METHOD
457 void DIEInteger::print(raw_ostream &O) const {
458   O << "Int: " << (int64_t)Integer << "  0x";
459   O.write_hex(Integer);
460 }
461 
462 //===----------------------------------------------------------------------===//
463 // DIEExpr Implementation
464 //===----------------------------------------------------------------------===//
465 
466 /// EmitValue - Emit expression value.
467 ///
468 void DIEExpr::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
469   AP->emitDebugValue(Expr, SizeOf(AP, Form));
470 }
471 
472 /// SizeOf - Determine size of expression value in bytes.
473 ///
474 unsigned DIEExpr::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
475   switch (Form) {
476   case dwarf::DW_FORM_data4:
477     return 4;
478   case dwarf::DW_FORM_data8:
479     return 8;
480   case dwarf::DW_FORM_sec_offset:
481     // FIXME: add support for DWARF64
482     return 4;
483   default:
484     llvm_unreachable("DIE Value form not supported yet");
485   }
486 }
487 
488 LLVM_DUMP_METHOD
489 void DIEExpr::print(raw_ostream &O) const { O << "Expr: " << *Expr; }
490 
491 //===----------------------------------------------------------------------===//
492 // DIELabel Implementation
493 //===----------------------------------------------------------------------===//
494 
495 /// EmitValue - Emit label value.
496 ///
497 void DIELabel::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
498   AP->emitLabelReference(
499       Label, SizeOf(AP, Form),
500       Form == dwarf::DW_FORM_strp || Form == dwarf::DW_FORM_sec_offset ||
501           Form == dwarf::DW_FORM_ref_addr || Form == dwarf::DW_FORM_data4);
502 }
503 
504 /// SizeOf - Determine size of label value in bytes.
505 ///
506 unsigned DIELabel::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
507   if (Form == dwarf::DW_FORM_data4) return 4;
508   if (Form == dwarf::DW_FORM_sec_offset) return 4;
509   if (Form == dwarf::DW_FORM_strp) return 4;
510   return AP->MAI->getCodePointerSize();
511 }
512 
513 LLVM_DUMP_METHOD
514 void DIELabel::print(raw_ostream &O) const { O << "Lbl: " << Label->getName(); }
515 
516 //===----------------------------------------------------------------------===//
517 // DIEBaseTypeRef Implementation
518 //===----------------------------------------------------------------------===//
519 
520 void DIEBaseTypeRef::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
521   uint64_t Offset = CU->ExprRefedBaseTypes[Index].Die->getOffset();
522   assert(Offset < (1ULL << (ULEB128PadSize * 7)) && "Offset wont fit");
523   AP->emitULEB128(Offset, nullptr, ULEB128PadSize);
524 }
525 
526 unsigned DIEBaseTypeRef::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
527   return ULEB128PadSize;
528 }
529 
530 LLVM_DUMP_METHOD
531 void DIEBaseTypeRef::print(raw_ostream &O) const { O << "BaseTypeRef: " << Index; }
532 
533 //===----------------------------------------------------------------------===//
534 // DIEDelta Implementation
535 //===----------------------------------------------------------------------===//
536 
537 /// EmitValue - Emit delta value.
538 ///
539 void DIEDelta::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
540   AP->emitLabelDifference(LabelHi, LabelLo, SizeOf(AP, Form));
541 }
542 
543 /// SizeOf - Determine size of delta value in bytes.
544 ///
545 unsigned DIEDelta::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
546   if (Form == dwarf::DW_FORM_data4) return 4;
547   if (Form == dwarf::DW_FORM_sec_offset) return 4;
548   if (Form == dwarf::DW_FORM_strp) return 4;
549   return AP->MAI->getCodePointerSize();
550 }
551 
552 LLVM_DUMP_METHOD
553 void DIEDelta::print(raw_ostream &O) const {
554   O << "Del: " << LabelHi->getName() << "-" << LabelLo->getName();
555 }
556 
557 //===----------------------------------------------------------------------===//
558 // DIEString Implementation
559 //===----------------------------------------------------------------------===//
560 
561 /// EmitValue - Emit string value.
562 ///
563 void DIEString::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
564   // Index of string in symbol table.
565   switch (Form) {
566   case dwarf::DW_FORM_GNU_str_index:
567   case dwarf::DW_FORM_strx:
568   case dwarf::DW_FORM_strx1:
569   case dwarf::DW_FORM_strx2:
570   case dwarf::DW_FORM_strx3:
571   case dwarf::DW_FORM_strx4:
572     DIEInteger(S.getIndex()).emitValue(AP, Form);
573     return;
574   case dwarf::DW_FORM_strp:
575     if (AP->MAI->doesDwarfUseRelocationsAcrossSections())
576       DIELabel(S.getSymbol()).emitValue(AP, Form);
577     else
578       DIEInteger(S.getOffset()).emitValue(AP, Form);
579     return;
580   default:
581     llvm_unreachable("Expected valid string form");
582   }
583 }
584 
585 /// SizeOf - Determine size of delta value in bytes.
586 ///
587 unsigned DIEString::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
588   // Index of string in symbol table.
589   switch (Form) {
590   case dwarf::DW_FORM_GNU_str_index:
591   case dwarf::DW_FORM_strx:
592   case dwarf::DW_FORM_strx1:
593   case dwarf::DW_FORM_strx2:
594   case dwarf::DW_FORM_strx3:
595   case dwarf::DW_FORM_strx4:
596     return DIEInteger(S.getIndex()).SizeOf(AP, Form);
597   case dwarf::DW_FORM_strp:
598     if (AP->MAI->doesDwarfUseRelocationsAcrossSections())
599       return DIELabel(S.getSymbol()).SizeOf(AP, Form);
600     return DIEInteger(S.getOffset()).SizeOf(AP, Form);
601   default:
602     llvm_unreachable("Expected valid string form");
603   }
604 }
605 
606 LLVM_DUMP_METHOD
607 void DIEString::print(raw_ostream &O) const {
608   O << "String: " << S.getString();
609 }
610 
611 //===----------------------------------------------------------------------===//
612 // DIEInlineString Implementation
613 //===----------------------------------------------------------------------===//
614 void DIEInlineString::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
615   if (Form == dwarf::DW_FORM_string) {
616     AP->OutStreamer->emitBytes(S);
617     AP->emitInt8(0);
618     return;
619   }
620   llvm_unreachable("Expected valid string form");
621 }
622 
623 unsigned DIEInlineString::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
624   // Emit string bytes + NULL byte.
625   return S.size() + 1;
626 }
627 
628 LLVM_DUMP_METHOD
629 void DIEInlineString::print(raw_ostream &O) const {
630   O << "InlineString: " << S;
631 }
632 
633 //===----------------------------------------------------------------------===//
634 // DIEEntry Implementation
635 //===----------------------------------------------------------------------===//
636 
637 /// EmitValue - Emit debug information entry offset.
638 ///
639 void DIEEntry::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
640 
641   switch (Form) {
642   case dwarf::DW_FORM_ref1:
643   case dwarf::DW_FORM_ref2:
644   case dwarf::DW_FORM_ref4:
645   case dwarf::DW_FORM_ref8:
646     AP->OutStreamer->emitIntValue(Entry->getOffset(), SizeOf(AP, Form));
647     return;
648 
649   case dwarf::DW_FORM_ref_udata:
650     AP->emitULEB128(Entry->getOffset());
651     return;
652 
653   case dwarf::DW_FORM_ref_addr: {
654     // Get the absolute offset for this DIE within the debug info/types section.
655     unsigned Addr = Entry->getDebugSectionOffset();
656     if (const MCSymbol *SectionSym =
657             Entry->getUnit()->getCrossSectionRelativeBaseAddress()) {
658       AP->emitLabelPlusOffset(SectionSym, Addr, SizeOf(AP, Form), true);
659       return;
660     }
661 
662     AP->OutStreamer->emitIntValue(Addr, SizeOf(AP, Form));
663     return;
664   }
665   default:
666     llvm_unreachable("Improper form for DIE reference");
667   }
668 }
669 
670 unsigned DIEEntry::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
671   switch (Form) {
672   case dwarf::DW_FORM_ref1:
673     return 1;
674   case dwarf::DW_FORM_ref2:
675     return 2;
676   case dwarf::DW_FORM_ref4:
677     return 4;
678   case dwarf::DW_FORM_ref8:
679     return 8;
680   case dwarf::DW_FORM_ref_udata:
681     return getULEB128Size(Entry->getOffset());
682   case dwarf::DW_FORM_ref_addr:
683     if (AP->getDwarfVersion() == 2)
684       return AP->MAI->getCodePointerSize();
685     switch (AP->OutStreamer->getContext().getDwarfFormat()) {
686     case dwarf::DWARF32:
687       return 4;
688     case dwarf::DWARF64:
689       return 8;
690     }
691     llvm_unreachable("Invalid DWARF format");
692 
693   default:
694     llvm_unreachable("Improper form for DIE reference");
695   }
696 }
697 
698 LLVM_DUMP_METHOD
699 void DIEEntry::print(raw_ostream &O) const {
700   O << format("Die: 0x%lx", (long)(intptr_t)&Entry);
701 }
702 
703 //===----------------------------------------------------------------------===//
704 // DIELoc Implementation
705 //===----------------------------------------------------------------------===//
706 
707 /// ComputeSize - calculate the size of the location expression.
708 ///
709 unsigned DIELoc::ComputeSize(const AsmPrinter *AP) const {
710   if (!Size) {
711     for (const auto &V : values())
712       Size += V.SizeOf(AP);
713   }
714 
715   return Size;
716 }
717 
718 /// EmitValue - Emit location data.
719 ///
720 void DIELoc::emitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
721   switch (Form) {
722   default: llvm_unreachable("Improper form for block");
723   case dwarf::DW_FORM_block1: Asm->emitInt8(Size);    break;
724   case dwarf::DW_FORM_block2: Asm->emitInt16(Size);   break;
725   case dwarf::DW_FORM_block4: Asm->emitInt32(Size);   break;
726   case dwarf::DW_FORM_block:
727   case dwarf::DW_FORM_exprloc:
728     Asm->emitULEB128(Size);
729     break;
730   }
731 
732   for (const auto &V : values())
733     V.emitValue(Asm);
734 }
735 
736 /// SizeOf - Determine size of location data in bytes.
737 ///
738 unsigned DIELoc::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
739   switch (Form) {
740   case dwarf::DW_FORM_block1: return Size + sizeof(int8_t);
741   case dwarf::DW_FORM_block2: return Size + sizeof(int16_t);
742   case dwarf::DW_FORM_block4: return Size + sizeof(int32_t);
743   case dwarf::DW_FORM_block:
744   case dwarf::DW_FORM_exprloc:
745     return Size + getULEB128Size(Size);
746   default: llvm_unreachable("Improper form for block");
747   }
748 }
749 
750 LLVM_DUMP_METHOD
751 void DIELoc::print(raw_ostream &O) const {
752   printValues(O, *this, "ExprLoc", Size, 5);
753 }
754 
755 //===----------------------------------------------------------------------===//
756 // DIEBlock Implementation
757 //===----------------------------------------------------------------------===//
758 
759 /// ComputeSize - calculate the size of the block.
760 ///
761 unsigned DIEBlock::ComputeSize(const AsmPrinter *AP) const {
762   if (!Size) {
763     for (const auto &V : values())
764       Size += V.SizeOf(AP);
765   }
766 
767   return Size;
768 }
769 
770 /// EmitValue - Emit block data.
771 ///
772 void DIEBlock::emitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
773   switch (Form) {
774   default: llvm_unreachable("Improper form for block");
775   case dwarf::DW_FORM_block1: Asm->emitInt8(Size);    break;
776   case dwarf::DW_FORM_block2: Asm->emitInt16(Size);   break;
777   case dwarf::DW_FORM_block4: Asm->emitInt32(Size);   break;
778   case dwarf::DW_FORM_block:
779     Asm->emitULEB128(Size);
780     break;
781   case dwarf::DW_FORM_string: break;
782   case dwarf::DW_FORM_data16: break;
783   }
784 
785   for (const auto &V : values())
786     V.emitValue(Asm);
787 }
788 
789 /// SizeOf - Determine size of block data in bytes.
790 ///
791 unsigned DIEBlock::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
792   switch (Form) {
793   case dwarf::DW_FORM_block1: return Size + sizeof(int8_t);
794   case dwarf::DW_FORM_block2: return Size + sizeof(int16_t);
795   case dwarf::DW_FORM_block4: return Size + sizeof(int32_t);
796   case dwarf::DW_FORM_block:  return Size + getULEB128Size(Size);
797   case dwarf::DW_FORM_data16: return 16;
798   default: llvm_unreachable("Improper form for block");
799   }
800 }
801 
802 LLVM_DUMP_METHOD
803 void DIEBlock::print(raw_ostream &O) const {
804   printValues(O, *this, "Blk", Size, 5);
805 }
806 
807 //===----------------------------------------------------------------------===//
808 // DIELocList Implementation
809 //===----------------------------------------------------------------------===//
810 
811 unsigned DIELocList::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
812   switch (Form) {
813   case dwarf::DW_FORM_loclistx:
814     return getULEB128Size(Index);
815   case dwarf::DW_FORM_data4:
816     return 4;
817   case dwarf::DW_FORM_sec_offset:
818     // FIXME: add support for DWARF64
819     return 4;
820   default:
821     llvm_unreachable("DIE Value form not supported yet");
822   }
823 }
824 
825 /// EmitValue - Emit label value.
826 ///
827 void DIELocList::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
828   if (Form == dwarf::DW_FORM_loclistx) {
829     AP->emitULEB128(Index);
830     return;
831   }
832   DwarfDebug *DD = AP->getDwarfDebug();
833   MCSymbol *Label = DD->getDebugLocs().getList(Index).Label;
834   AP->emitDwarfSymbolReference(Label, /*ForceOffset*/ DD->useSplitDwarf());
835 }
836 
837 LLVM_DUMP_METHOD
838 void DIELocList::print(raw_ostream &O) const { O << "LocList: " << Index; }
839