1 //===-- llvm/CodeGen/DwarfDebug.h - Dwarf Debug Framework ------*- C++ -*--===//
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 contains support for writing dwarf debug info into asm files.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
15 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
16 
17 #include "DwarfFile.h"
18 #include "AsmPrinterHandler.h"
19 #include "DIE.h"
20 #include "DbgValueHistoryCalculator.h"
21 #include "DebugLocEntry.h"
22 #include "DebugLocList.h"
23 #include "DwarfAccelTable.h"
24 #include "llvm/ADT/DenseMap.h"
25 #include "llvm/ADT/MapVector.h"
26 #include "llvm/ADT/SmallPtrSet.h"
27 #include "llvm/ADT/StringMap.h"
28 #include "llvm/ADT/FoldingSet.h"
29 #include "llvm/CodeGen/LexicalScopes.h"
30 #include "llvm/CodeGen/MachineInstr.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/DebugLoc.h"
33 #include "llvm/MC/MachineLocation.h"
34 #include "llvm/MC/MCDwarf.h"
35 #include "llvm/Support/Allocator.h"
36 
37 #include <memory>
38 
39 namespace llvm {
40 
41 class AsmPrinter;
42 class ByteStreamer;
43 class ConstantInt;
44 class ConstantFP;
45 class DwarfCompileUnit;
46 class DwarfDebug;
47 class DwarfTypeUnit;
48 class DwarfUnit;
49 class MachineModuleInfo;
50 
51 //===----------------------------------------------------------------------===//
52 /// \brief This class is used to record source line correspondence.
53 class SrcLineInfo {
54   unsigned Line;     // Source line number.
55   unsigned Column;   // Source column.
56   unsigned SourceID; // Source ID number.
57   MCSymbol *Label;   // Label in code ID number.
58 public:
59   SrcLineInfo(unsigned L, unsigned C, unsigned S, MCSymbol *label)
60       : Line(L), Column(C), SourceID(S), Label(label) {}
61 
62   // Accessors
63   unsigned getLine() const { return Line; }
64   unsigned getColumn() const { return Column; }
65   unsigned getSourceID() const { return SourceID; }
66   MCSymbol *getLabel() const { return Label; }
67 };
68 
69 //===----------------------------------------------------------------------===//
70 /// \brief This class is used to track local variable information.
71 class DbgVariable {
72   DIVariable Var;             // Variable Descriptor.
73   DIExpression Expr;          // Complex address location expression.
74   DIE *TheDIE;                // Variable DIE.
75   unsigned DotDebugLocOffset; // Offset in DotDebugLocEntries.
76   const MachineInstr *MInsn;  // DBG_VALUE instruction of the variable.
77   int FrameIndex;
78   DwarfDebug *DD;
79 
80 public:
81   /// Construct a DbgVariable from a DIVariable.
82   DbgVariable(DIVariable V, DIExpression E, DwarfDebug *DD)
83       : Var(V), Expr(E), TheDIE(nullptr), DotDebugLocOffset(~0U),
84         MInsn(nullptr), FrameIndex(~0), DD(DD) {
85     assert(Var.Verify() && Expr.Verify());
86   }
87 
88   /// Construct a DbgVariable from a DEBUG_VALUE.
89   /// AbstractVar may be NULL.
90   DbgVariable(const MachineInstr *DbgValue, DwarfDebug *DD)
91       : Var(DbgValue->getDebugVariable()), Expr(DbgValue->getDebugExpression()),
92         TheDIE(nullptr), DotDebugLocOffset(~0U), MInsn(DbgValue),
93         FrameIndex(~0), DD(DD) {}
94 
95   // Accessors.
96   DIVariable getVariable() const { return Var; }
97   DIExpression getExpression() const { return Expr; }
98   void setDIE(DIE &D) { TheDIE = &D; }
99   DIE *getDIE() const { return TheDIE; }
100   void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
101   unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
102   StringRef getName() const { return Var.getName(); }
103   const MachineInstr *getMInsn() const { return MInsn; }
104   int getFrameIndex() const { return FrameIndex; }
105   void setFrameIndex(int FI) { FrameIndex = FI; }
106   // Translate tag to proper Dwarf tag.
107   dwarf::Tag getTag() const {
108     if (Var.getTag() == dwarf::DW_TAG_arg_variable)
109       return dwarf::DW_TAG_formal_parameter;
110 
111     return dwarf::DW_TAG_variable;
112   }
113   /// \brief Return true if DbgVariable is artificial.
114   bool isArtificial() const {
115     if (Var.isArtificial())
116       return true;
117     if (getType().isArtificial())
118       return true;
119     return false;
120   }
121 
122   bool isObjectPointer() const {
123     if (Var.isObjectPointer())
124       return true;
125     if (getType().isObjectPointer())
126       return true;
127     return false;
128   }
129 
130   bool variableHasComplexAddress() const {
131     assert(Var.isVariable() && "Invalid complex DbgVariable!");
132     return Expr.getNumElements() > 0;
133   }
134   bool isBlockByrefVariable() const;
135   unsigned getNumAddrElements() const {
136     assert(Var.isVariable() && "Invalid complex DbgVariable!");
137     return Expr.getNumElements();
138   }
139   uint64_t getAddrElement(unsigned i) const { return Expr.getElement(i); }
140   DIType getType() const;
141 
142 private:
143   /// resolve - Look in the DwarfDebug map for the MDNode that
144   /// corresponds to the reference.
145   template <typename T> T resolve(DIRef<T> Ref) const;
146 };
147 
148 
149 /// \brief Helper used to pair up a symbol and its DWARF compile unit.
150 struct SymbolCU {
151   SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
152   const MCSymbol *Sym;
153   DwarfCompileUnit *CU;
154 };
155 
156 /// \brief Collects and handles dwarf debug information.
157 class DwarfDebug : public AsmPrinterHandler {
158   // Target of Dwarf emission.
159   AsmPrinter *Asm;
160 
161   // Collected machine module information.
162   MachineModuleInfo *MMI;
163 
164   // All DIEValues are allocated through this allocator.
165   BumpPtrAllocator DIEValueAllocator;
166 
167   // Maps MDNode with its corresponding DwarfCompileUnit.
168   MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
169 
170   // Maps subprogram MDNode with its corresponding DwarfCompileUnit.
171   MapVector<const MDNode *, DwarfCompileUnit *> SPMap;
172 
173   // Maps a CU DIE with its corresponding DwarfCompileUnit.
174   DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
175 
176   /// Maps MDNodes for type system with the corresponding DIEs. These DIEs can
177   /// be shared across CUs, that is why we keep the map here instead
178   /// of in DwarfCompileUnit.
179   DenseMap<const MDNode *, DIE *> MDTypeNodeToDieMap;
180 
181   // List of all labels used in aranges generation.
182   std::vector<SymbolCU> ArangeLabels;
183 
184   // Size of each symbol emitted (for those symbols that have a specific size).
185   DenseMap<const MCSymbol *, uint64_t> SymSize;
186 
187   // Provides a unique id per text section.
188   typedef DenseMap<const MCSection *, SmallVector<SymbolCU, 8> > SectionMapType;
189   SectionMapType SectionMap;
190 
191   LexicalScopes LScopes;
192 
193   // Collection of abstract subprogram DIEs.
194   DenseMap<const MDNode *, DIE *> AbstractSPDies;
195 
196   // Collection of abstract variables.
197   DenseMap<const MDNode *, std::unique_ptr<DbgVariable>> AbstractVariables;
198   SmallVector<std::unique_ptr<DbgVariable>, 64> ConcreteVariables;
199 
200   // Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
201   // can refer to them in spite of insertions into this list.
202   SmallVector<DebugLocList, 4> DotDebugLocEntries;
203 
204   // This is a collection of subprogram MDNodes that are processed to
205   // create DIEs.
206   SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
207 
208   // Maps instruction with label emitted before instruction.
209   DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
210 
211   // Maps instruction with label emitted after instruction.
212   DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
213 
214   // History of DBG_VALUE and clobber instructions for each user variable.
215   // Variables are listed in order of appearance.
216   DbgValueHistoryMap DbgValues;
217 
218   // Previous instruction's location information. This is used to determine
219   // label location to indicate scope boundries in dwarf debug info.
220   DebugLoc PrevInstLoc;
221   MCSymbol *PrevLabel;
222 
223   // This location indicates end of function prologue and beginning of function
224   // body.
225   DebugLoc PrologEndLoc;
226 
227   // If nonnull, stores the current machine function we're processing.
228   const MachineFunction *CurFn;
229 
230   // If nonnull, stores the current machine instruction we're processing.
231   const MachineInstr *CurMI;
232 
233   // If nonnull, stores the CU in which the previous subprogram was contained.
234   const DwarfCompileUnit *PrevCU;
235 
236   // Section Symbols: these are assembler temporary labels that are emitted at
237   // the beginning of each supported dwarf section.  These are used to form
238   // section offsets and are created by EmitSectionLabels.
239   MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
240   MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
241   MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
242   MCSymbol *FunctionBeginSym, *FunctionEndSym;
243   MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
244   MCSymbol *DwarfTypesDWOSectionSym;
245   MCSymbol *DwarfStrDWOSectionSym;
246   MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
247 
248   // As an optimization, there is no need to emit an entry in the directory
249   // table for the same directory as DW_AT_comp_dir.
250   StringRef CompilationDir;
251 
252   // Counter for assigning globally unique IDs for ranges.
253   unsigned GlobalRangeCount;
254 
255   // Holder for the file specific debug information.
256   DwarfFile InfoHolder;
257 
258   // Holders for the various debug information flags that we might need to
259   // have exposed. See accessor functions below for description.
260 
261   // Holder for imported entities.
262   typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
263   ImportedEntityMap;
264   ImportedEntityMap ScopesWithImportedEntities;
265 
266   // Map from MDNodes for user-defined types to the type units that describe
267   // them.
268   DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
269 
270   SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
271 
272   // Whether to emit the pubnames/pubtypes sections.
273   bool HasDwarfPubSections;
274 
275   // Whether or not to use AT_ranges for compilation units.
276   bool HasCURanges;
277 
278   // Whether we emitted a function into a section other than the default
279   // text.
280   bool UsedNonDefaultText;
281 
282   // Version of dwarf we're emitting.
283   unsigned DwarfVersion;
284 
285   // Maps from a type identifier to the actual MDNode.
286   DITypeIdentifierMap TypeIdentifierMap;
287 
288   // DWARF5 Experimental Options
289   bool HasDwarfAccelTables;
290   bool HasSplitDwarf;
291 
292   // Separated Dwarf Variables
293   // In general these will all be for bits that are left in the
294   // original object file, rather than things that are meant
295   // to be in the .dwo sections.
296 
297   // Holder for the skeleton information.
298   DwarfFile SkeletonHolder;
299 
300   /// Store file names for type units under fission in a line table header that
301   /// will be emitted into debug_line.dwo.
302   // FIXME: replace this with a map from comp_dir to table so that we can emit
303   // multiple tables during LTO each of which uses directory 0, referencing the
304   // comp_dir of all the type units that use it.
305   MCDwarfDwoLineTable SplitTypeUnitFileTable;
306 
307   // True iff there are multiple CUs in this module.
308   bool SingleCU;
309   bool IsDarwin;
310 
311   AddressPool AddrPool;
312 
313   DwarfAccelTable AccelNames;
314   DwarfAccelTable AccelObjC;
315   DwarfAccelTable AccelNamespace;
316   DwarfAccelTable AccelTypes;
317 
318   DenseMap<const Function *, DISubprogram> FunctionDIs;
319 
320   MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
321 
322   const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
323     return InfoHolder.getUnits();
324   }
325 
326   /// \brief Find abstract variable associated with Var.
327   DbgVariable *getExistingAbstractVariable(const DIVariable &DV,
328                                            DIVariable &Cleansed);
329   DbgVariable *getExistingAbstractVariable(const DIVariable &DV);
330   void createAbstractVariable(const DIVariable &DV, LexicalScope *Scope);
331   void ensureAbstractVariableIsCreated(const DIVariable &Var,
332                                        const MDNode *Scope);
333   void ensureAbstractVariableIsCreatedIfScoped(const DIVariable &Var,
334                                                const MDNode *Scope);
335 
336   /// \brief Construct a DIE for this abstract scope.
337   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
338 
339   /// \brief Emit initial Dwarf sections with a label at the start of each one.
340   void emitSectionLabels();
341 
342   /// \brief Compute the size and offset of a DIE given an incoming Offset.
343   unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
344 
345   /// \brief Compute the size and offset of all the DIEs.
346   void computeSizeAndOffsets();
347 
348   /// \brief Collect info for variables that were optimized out.
349   void collectDeadVariables();
350 
351   void finishVariableDefinitions();
352 
353   void finishSubprogramDefinitions();
354 
355   /// \brief Finish off debug information after all functions have been
356   /// processed.
357   void finalizeModuleInfo();
358 
359   /// \brief Emit labels to close any remaining sections that have been left
360   /// open.
361   void endSections();
362 
363   /// \brief Emit the debug info section.
364   void emitDebugInfo();
365 
366   /// \brief Emit the abbreviation section.
367   void emitAbbreviations();
368 
369   /// \brief Emit the last address of the section and the end of
370   /// the line matrix.
371   void emitEndOfLineMatrix(unsigned SectionEnd);
372 
373   /// \brief Emit a specified accelerator table.
374   void emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
375                  StringRef TableName, StringRef SymName);
376 
377   /// \brief Emit visible names into a hashed accelerator table section.
378   void emitAccelNames();
379 
380   /// \brief Emit objective C classes and categories into a hashed
381   /// accelerator table section.
382   void emitAccelObjC();
383 
384   /// \brief Emit namespace dies into a hashed accelerator table.
385   void emitAccelNamespaces();
386 
387   /// \brief Emit type dies into a hashed accelerator table.
388   void emitAccelTypes();
389 
390   /// \brief Emit visible names into a debug pubnames section.
391   /// \param GnuStyle determines whether or not we want to emit
392   /// additional information into the table ala newer gcc for gdb
393   /// index.
394   void emitDebugPubNames(bool GnuStyle = false);
395 
396   /// \brief Emit visible types into a debug pubtypes section.
397   /// \param GnuStyle determines whether or not we want to emit
398   /// additional information into the table ala newer gcc for gdb
399   /// index.
400   void emitDebugPubTypes(bool GnuStyle = false);
401 
402   void
403   emitDebugPubSection(bool GnuStyle, const MCSection *PSec, StringRef Name,
404                       const StringMap<const DIE *> &(DwarfUnit::*Accessor)()
405                       const);
406 
407   /// \brief Emit visible names into a debug str section.
408   void emitDebugStr();
409 
410   /// \brief Emit visible names into a debug loc section.
411   void emitDebugLoc();
412 
413   /// \brief Emit visible names into a debug loc dwo section.
414   void emitDebugLocDWO();
415 
416   /// \brief Emit visible names into a debug aranges section.
417   void emitDebugARanges();
418 
419   /// \brief Emit visible names into a debug ranges section.
420   void emitDebugRanges();
421 
422   /// \brief Emit inline info using custom format.
423   void emitDebugInlineInfo();
424 
425   /// DWARF 5 Experimental Split Dwarf Emitters
426 
427   /// \brief Initialize common features of skeleton units.
428   void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
429                         std::unique_ptr<DwarfUnit> NewU);
430 
431   /// \brief Construct the split debug info compile unit for the debug info
432   /// section.
433   DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
434 
435   /// \brief Construct the split debug info compile unit for the debug info
436   /// section.
437   DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
438 
439   /// \brief Emit the debug info dwo section.
440   void emitDebugInfoDWO();
441 
442   /// \brief Emit the debug abbrev dwo section.
443   void emitDebugAbbrevDWO();
444 
445   /// \brief Emit the debug line dwo section.
446   void emitDebugLineDWO();
447 
448   /// \brief Emit the debug str dwo section.
449   void emitDebugStrDWO();
450 
451   /// Flags to let the linker know we have emitted new style pubnames. Only
452   /// emit it here if we don't have a skeleton CU for split dwarf.
453   void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
454 
455   /// \brief Create new DwarfCompileUnit for the given metadata node with tag
456   /// DW_TAG_compile_unit.
457   DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
458 
459   /// \brief Construct imported_module or imported_declaration DIE.
460   void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
461                                         const MDNode *N);
462 
463   /// \brief Register a source line with debug info. Returns the unique
464   /// label that was emitted and which provides correspondence to the
465   /// source line list.
466   void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
467                         unsigned Flags);
468 
469   /// \brief Indentify instructions that are marking the beginning of or
470   /// ending of a scope.
471   void identifyScopeMarkers();
472 
473   /// \brief Populate LexicalScope entries with variables' info.
474   void collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
475                            SmallPtrSetImpl<const MDNode *> &ProcessedVars);
476 
477   /// \brief Build the location list for all DBG_VALUEs in the
478   /// function that describe the same variable.
479   void buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
480                          const DbgValueHistoryMap::InstrRanges &Ranges);
481 
482   /// \brief Collect variable information from the side table maintained
483   /// by MMI.
484   void collectVariableInfoFromMMITable(SmallPtrSetImpl<const MDNode *> &P);
485 
486   /// \brief Ensure that a label will be emitted before MI.
487   void requestLabelBeforeInsn(const MachineInstr *MI) {
488     LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
489   }
490 
491   /// \brief Ensure that a label will be emitted after MI.
492   void requestLabelAfterInsn(const MachineInstr *MI) {
493     LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
494   }
495 
496 public:
497   //===--------------------------------------------------------------------===//
498   // Main entry points.
499   //
500   DwarfDebug(AsmPrinter *A, Module *M);
501 
502   ~DwarfDebug() override;
503 
504   void insertDIE(const MDNode *TypeMD, DIE *Die) {
505     MDTypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
506   }
507   DIE *getDIE(const MDNode *TypeMD) {
508     return MDTypeNodeToDieMap.lookup(TypeMD);
509   }
510 
511   /// \brief Emit all Dwarf sections that should come prior to the
512   /// content.
513   void beginModule();
514 
515   /// \brief Emit all Dwarf sections that should come after the content.
516   void endModule() override;
517 
518   /// \brief Gather pre-function debug information.
519   void beginFunction(const MachineFunction *MF) override;
520 
521   /// \brief Gather and emit post-function debug information.
522   void endFunction(const MachineFunction *MF) override;
523 
524   /// \brief Process beginning of an instruction.
525   void beginInstruction(const MachineInstr *MI) override;
526 
527   /// \brief Process end of an instruction.
528   void endInstruction() override;
529 
530   /// \brief Add a DIE to the set of types that we're going to pull into
531   /// type units.
532   void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
533                             DIE &Die, DICompositeType CTy);
534 
535   /// \brief Add a label so that arange data can be generated for it.
536   void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
537 
538   /// \brief For symbols that have a size designated (e.g. common symbols),
539   /// this tracks that size.
540   void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
541     SymSize[Sym] = Size;
542   }
543 
544   /// \brief Recursively Emits a debug information entry.
545   void emitDIE(DIE &Die);
546 
547   // Experimental DWARF5 features.
548 
549   /// \brief Returns whether or not to emit tables that dwarf consumers can
550   /// use to accelerate lookup.
551   bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
552 
553   /// \brief Returns whether or not to change the current debug info for the
554   /// split dwarf proposal support.
555   bool useSplitDwarf() const { return HasSplitDwarf; }
556 
557   /// Returns the Dwarf Version.
558   unsigned getDwarfVersion() const { return DwarfVersion; }
559 
560   /// Returns the section symbol for the .debug_loc section.
561   MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
562 
563   /// Returns the section symbol for the .debug_str section.
564   MCSymbol *getDebugStrSym() const { return DwarfStrSectionSym; }
565 
566   /// Returns the section symbol for the .debug_ranges section.
567   MCSymbol *getRangeSectionSym() const { return DwarfDebugRangeSectionSym; }
568 
569   /// Returns the previous CU that was being updated
570   const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
571   void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
572 
573   /// Returns the entries for the .debug_loc section.
574   const SmallVectorImpl<DebugLocList> &
575   getDebugLocEntries() const {
576     return DotDebugLocEntries;
577   }
578 
579   /// \brief Emit an entry for the debug loc section. This can be used to
580   /// handle an entry that's going to be emitted into the debug loc section.
581   void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
582   /// \brief emit a single value for the debug loc section.
583   void emitDebugLocValue(ByteStreamer &Streamer,
584                          const DebugLocEntry::Value &Value);
585   /// Emits an optimal (=sorted) sequence of DW_OP_pieces.
586   void emitLocPieces(ByteStreamer &Streamer,
587                      const DITypeIdentifierMap &Map,
588                      ArrayRef<DebugLocEntry::Value> Values);
589 
590   /// Emit the location for a debug loc entry, including the size header.
591   void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
592 
593   /// Find the MDNode for the given reference.
594   template <typename T> T resolve(DIRef<T> Ref) const {
595     return Ref.resolve(TypeIdentifierMap);
596   }
597 
598   /// \brief Return the TypeIdentifierMap.
599   const DITypeIdentifierMap &getTypeIdentifierMap() const {
600     return TypeIdentifierMap;
601   }
602 
603   /// Find the DwarfCompileUnit for the given CU Die.
604   DwarfCompileUnit *lookupUnit(const DIE *CU) const {
605     return CUDieMap.lookup(CU);
606   }
607   /// isSubprogramContext - Return true if Context is either a subprogram
608   /// or another context nested inside a subprogram.
609   bool isSubprogramContext(const MDNode *Context);
610 
611   void addSubprogramNames(DISubprogram SP, DIE &Die);
612 
613   AddressPool &getAddressPool() { return AddrPool; }
614 
615   void addAccelName(StringRef Name, const DIE &Die);
616 
617   void addAccelObjC(StringRef Name, const DIE &Die);
618 
619   void addAccelNamespace(StringRef Name, const DIE &Die);
620 
621   void addAccelType(StringRef Name, const DIE &Die, char Flags);
622 
623   const MachineFunction *getCurrentFunction() const { return CurFn; }
624   const MCSymbol *getFunctionBeginSym() const { return FunctionBeginSym; }
625   const MCSymbol *getFunctionEndSym() const { return FunctionEndSym; }
626 
627   iterator_range<ImportedEntityMap::const_iterator>
628   findImportedEntitiesForScope(const MDNode *Scope) const {
629     return make_range(std::equal_range(
630         ScopesWithImportedEntities.begin(), ScopesWithImportedEntities.end(),
631         std::pair<const MDNode *, const MDNode *>(Scope, nullptr),
632         less_first()));
633   }
634 
635   /// \brief A helper function to check whether the DIE for a given Scope is
636   /// going to be null.
637   bool isLexicalScopeDIENull(LexicalScope *Scope);
638 
639   /// \brief Return Label preceding the instruction.
640   MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
641 
642   /// \brief Return Label immediately following the instruction.
643   MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
644 
645   // FIXME: Consider rolling ranges up into DwarfDebug since we use a single
646   // range_base anyway, so there's no need to keep them as separate per-CU range
647   // lists. (though one day we might end up with a range.dwo section, in which
648   // case it'd go to DwarfFile)
649   unsigned getNextRangeNumber() { return GlobalRangeCount++; }
650 
651   // FIXME: Sink these functions down into DwarfFile/Dwarf*Unit.
652 
653   DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
654     return AbstractSPDies;
655   }
656 
657   SmallPtrSet<const MDNode *, 16> &getProcessedSPNodes() {
658     return ProcessedSPNodes;
659   }
660 };
661 } // End of namespace llvm
662 
663 #endif
664