1//===- llvm/CodeGen/DwarfDebug.h - Dwarf Debug Framework --------*- C++ -*-===//
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// This file contains support for writing dwarf debug info into asm files.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
14#define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
15
16#include "AddressPool.h"
17#include "DebugLocEntry.h"
18#include "DebugLocStream.h"
19#include "DwarfFile.h"
20#include "llvm/ADT/DenseMap.h"
21#include "llvm/ADT/DenseSet.h"
22#include "llvm/ADT/MapVector.h"
23#include "llvm/ADT/SetVector.h"
24#include "llvm/ADT/SmallPtrSet.h"
25#include "llvm/ADT/SmallVector.h"
26#include "llvm/ADT/StringMap.h"
27#include "llvm/ADT/StringRef.h"
28#include "llvm/BinaryFormat/Dwarf.h"
29#include "llvm/CodeGen/AccelTable.h"
30#include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
31#include "llvm/CodeGen/DebugHandlerBase.h"
32#include "llvm/IR/DebugInfoMetadata.h"
33#include "llvm/IR/DebugLoc.h"
34#include "llvm/IR/Metadata.h"
35#include "llvm/MC/MCDwarf.h"
36#include "llvm/Support/Allocator.h"
37#include "llvm/Target/TargetOptions.h"
38#include <cassert>
39#include <cstdint>
40#include <limits>
41#include <memory>
42#include <utility>
43#include <variant>
44#include <vector>
45
46namespace llvm {
47
48class AsmPrinter;
49class ByteStreamer;
50class DIE;
51class DwarfCompileUnit;
52class DwarfExpression;
53class DwarfTypeUnit;
54class DwarfUnit;
55class LexicalScope;
56class MachineFunction;
57class MCSection;
58class MCSymbol;
59class Module;
60
61//===----------------------------------------------------------------------===//
62/// This class is defined as the common parent of DbgVariable and DbgLabel
63/// such that it could levarage polymorphism to extract common code for
64/// DbgVariable and DbgLabel.
65class DbgEntity {
66public:
67 enum DbgEntityKind {
68 DbgVariableKind,
69 DbgLabelKind
70 };
71
72private:
73 const DINode *Entity;
74 const DILocation *InlinedAt;
75 DIE *TheDIE = nullptr;
76 const DbgEntityKind SubclassID;
77
78public:
79 DbgEntity(const DINode *N, const DILocation *IA, DbgEntityKind ID)
80 : Entity(N), InlinedAt(IA), SubclassID(ID) {}
81 virtual ~DbgEntity() = default;
82
83 /// Accessors.
84 /// @{
85 const DINode *getEntity() const { return Entity; }
86 const DILocation *getInlinedAt() const { return InlinedAt; }
87 DIE *getDIE() const { return TheDIE; }
88 DbgEntityKind getDbgEntityID() const { return SubclassID; }
89 /// @}
90
91 void setDIE(DIE &D) { TheDIE = &D; }
92
93 static bool classof(const DbgEntity *N) {
94 switch (N->getDbgEntityID()) {
95 case DbgVariableKind:
96 case DbgLabelKind:
97 return true;
98 }
99 llvm_unreachable("Invalid DbgEntityKind");
100 }
101};
102
103class DbgVariable;
104
105bool operator<(const struct FrameIndexExpr &LHS,
106 const struct FrameIndexExpr &RHS);
107bool operator<(const struct EntryValueInfo &LHS,
108 const struct EntryValueInfo &RHS);
109
110/// Proxy for one MMI entry.
111struct FrameIndexExpr {
112 int FI;
113 const DIExpression *Expr;
114
115 /// Operator enabling sorting based on fragment offset.
116 friend bool operator<(const FrameIndexExpr &LHS, const FrameIndexExpr &RHS);
117};
118
119/// Represents an entry-value location, or a fragment of one.
120struct EntryValueInfo {
121 MCRegister Reg;
122 const DIExpression &Expr;
123
124 /// Operator enabling sorting based on fragment offset.
125 friend bool operator<(const EntryValueInfo &LHS, const EntryValueInfo &RHS);
126};
127
128// Namespace for alternatives of a DbgVariable.
129namespace Loc {
130/// Single value location description.
131class Single {
132 std::unique_ptr<DbgValueLoc> ValueLoc;
133 const DIExpression *Expr;
134
135public:
136 explicit Single(DbgValueLoc ValueLoc);
137 explicit Single(const MachineInstr *DbgValue);
138 const DbgValueLoc &getValueLoc() const { return *ValueLoc; }
139 const DIExpression *getExpr() const { return Expr; }
140};
141/// Multi-value location description.
142class Multi {
143 /// Index of the entry list in DebugLocs.
144 unsigned DebugLocListIndex;
145 /// DW_OP_LLVM_tag_offset value from DebugLocs.
146 std::optional<uint8_t> DebugLocListTagOffset;
147
148public:
149 explicit Multi(unsigned DebugLocListIndex,
150 std::optional<uint8_t> DebugLocListTagOffset)
151 : DebugLocListIndex(DebugLocListIndex),
152 DebugLocListTagOffset(DebugLocListTagOffset) {}
153 unsigned getDebugLocListIndex() const { return DebugLocListIndex; }
154 std::optional<uint8_t> getDebugLocListTagOffset() const {
155 return DebugLocListTagOffset;
156 }
157};
158/// Single location defined by (potentially multiple) MMI entries.
159struct MMI {
160 std::set<FrameIndexExpr> FrameIndexExprs;
161
162public:
163 explicit MMI(const DIExpression *E, int FI) : FrameIndexExprs({{.FI: FI, .Expr: E}}) {
164 assert((!E || E->isValid()) && "Expected valid expression");
165 assert(FI != std::numeric_limits<int>::max() && "Expected valid index");
166 }
167 void addFrameIndexExpr(const DIExpression *Expr, int FI);
168 /// Get the FI entries, sorted by fragment offset.
169 const std::set<FrameIndexExpr> &getFrameIndexExprs() const;
170};
171/// Single location defined by (potentially multiple) EntryValueInfo.
172struct EntryValue {
173 std::set<EntryValueInfo> EntryValues;
174 explicit EntryValue(MCRegister Reg, const DIExpression &Expr) {
175 addExpr(Reg, Expr);
176 };
177 // Add the pair Reg, Expr to the list of entry values describing the variable.
178 // If multiple expressions are added, it is the callers responsibility to
179 // ensure they are all non-overlapping fragments.
180 void addExpr(MCRegister Reg, const DIExpression &Expr) {
181 std::optional<const DIExpression *> NonVariadicExpr =
182 DIExpression::convertToNonVariadicExpression(Expr: &Expr);
183 assert(NonVariadicExpr && *NonVariadicExpr);
184
185 EntryValues.insert(x: {.Reg: Reg, .Expr: **NonVariadicExpr});
186 }
187};
188/// Alias for the std::variant specialization base class of DbgVariable.
189using Variant = std::variant<std::monostate, Loc::Single, Loc::Multi, Loc::MMI,
190 Loc::EntryValue>;
191} // namespace Loc
192
193//===----------------------------------------------------------------------===//
194/// This class is used to track local variable information.
195///
196/// Variables that have been optimized out hold the \c monostate alternative.
197/// This is not distinguished from the case of a constructed \c DbgVariable
198/// which has not be initialized yet.
199///
200/// Variables can be created from allocas, in which case they're generated from
201/// the MMI table. Such variables hold the \c Loc::MMI alternative which can
202/// have multiple expressions and frame indices.
203///
204/// Variables can be created from the entry value of registers, in which case
205/// they're generated from the MMI table. Such variables hold the \c
206/// EntryValueLoc alternative which can either have a single expression or
207/// multiple *fragment* expressions.
208///
209/// Variables can be created from \c DBG_VALUE instructions. Those whose
210/// location changes over time hold a \c Loc::Multi alternative which uses \c
211/// DebugLocListIndex and (optionally) \c DebugLocListTagOffset, while those
212/// with a single location hold a \c Loc::Single alternative which use \c
213/// ValueLoc and (optionally) a single \c Expr.
214class DbgVariable : public DbgEntity, public Loc::Variant {
215
216public:
217 /// To workaround P2162R0 https://github.com/cplusplus/papers/issues/873 the
218 /// base class subobject needs to be passed directly to std::visit, so expose
219 /// it directly here.
220 Loc::Variant &asVariant() { return *static_cast<Loc::Variant *>(this); }
221 const Loc::Variant &asVariant() const {
222 return *static_cast<const Loc::Variant *>(this);
223 }
224 /// Member shorthand for std::holds_alternative
225 template <typename T> bool holds() const {
226 return std::holds_alternative<T>(*this);
227 }
228 /// Asserting, noexcept member alternative to std::get
229 template <typename T> auto &get() noexcept {
230 assert(holds<T>());
231 return *std::get_if<T>(this);
232 }
233 /// Asserting, noexcept member alternative to std::get
234 template <typename T> const auto &get() const noexcept {
235 assert(holds<T>());
236 return *std::get_if<T>(this);
237 }
238
239 /// Construct a DbgVariable.
240 ///
241 /// Creates a variable without any DW_AT_location.
242 DbgVariable(const DILocalVariable *V, const DILocation *IA)
243 : DbgEntity(V, IA, DbgVariableKind) {}
244
245 // Accessors.
246 const DILocalVariable *getVariable() const {
247 return cast<DILocalVariable>(Val: getEntity());
248 }
249
250 StringRef getName() const { return getVariable()->getName(); }
251
252 // Translate tag to proper Dwarf tag.
253 dwarf::Tag getTag() const {
254 // FIXME: Why don't we just infer this tag and store it all along?
255 if (getVariable()->isParameter())
256 return dwarf::DW_TAG_formal_parameter;
257
258 return dwarf::DW_TAG_variable;
259 }
260
261 /// Return true if DbgVariable is artificial.
262 bool isArtificial() const {
263 if (getVariable()->isArtificial())
264 return true;
265 if (getType()->isArtificial())
266 return true;
267 return false;
268 }
269
270 bool isObjectPointer() const {
271 if (getVariable()->isObjectPointer())
272 return true;
273 if (getType()->isObjectPointer())
274 return true;
275 return false;
276 }
277
278 const DIType *getType() const;
279
280 static bool classof(const DbgEntity *N) {
281 return N->getDbgEntityID() == DbgVariableKind;
282 }
283};
284
285//===----------------------------------------------------------------------===//
286/// This class is used to track label information.
287///
288/// Labels are collected from \c DBG_LABEL instructions.
289class DbgLabel : public DbgEntity {
290 const MCSymbol *Sym; /// Symbol before DBG_LABEL instruction.
291
292public:
293 /// We need MCSymbol information to generate DW_AT_low_pc.
294 DbgLabel(const DILabel *L, const DILocation *IA, const MCSymbol *Sym = nullptr)
295 : DbgEntity(L, IA, DbgLabelKind), Sym(Sym) {}
296
297 /// Accessors.
298 /// @{
299 const DILabel *getLabel() const { return cast<DILabel>(Val: getEntity()); }
300 const MCSymbol *getSymbol() const { return Sym; }
301
302 StringRef getName() const { return getLabel()->getName(); }
303 /// @}
304
305 /// Translate tag to proper Dwarf tag.
306 dwarf::Tag getTag() const {
307 return dwarf::DW_TAG_label;
308 }
309
310 static bool classof(const DbgEntity *N) {
311 return N->getDbgEntityID() == DbgLabelKind;
312 }
313};
314
315/// Used for tracking debug info about call site parameters.
316class DbgCallSiteParam {
317private:
318 unsigned Register; ///< Parameter register at the callee entry point.
319 DbgValueLoc Value; ///< Corresponding location for the parameter value at
320 ///< the call site.
321public:
322 DbgCallSiteParam(unsigned Reg, DbgValueLoc Val)
323 : Register(Reg), Value(Val) {
324 assert(Reg && "Parameter register cannot be undef");
325 }
326
327 unsigned getRegister() const { return Register; }
328 DbgValueLoc getValue() const { return Value; }
329};
330
331/// Collection used for storing debug call site parameters.
332using ParamSet = SmallVector<DbgCallSiteParam, 4>;
333
334/// Helper used to pair up a symbol and its DWARF compile unit.
335struct SymbolCU {
336 SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
337
338 const MCSymbol *Sym;
339 DwarfCompileUnit *CU;
340};
341
342/// The kind of accelerator tables we should emit.
343enum class AccelTableKind {
344 Default, ///< Platform default.
345 None, ///< None.
346 Apple, ///< .apple_names, .apple_namespaces, .apple_types, .apple_objc.
347 Dwarf, ///< DWARF v5 .debug_names.
348};
349
350/// Collects and handles dwarf debug information.
351class DwarfDebug : public DebugHandlerBase {
352 /// All DIEValues are allocated through this allocator.
353 BumpPtrAllocator DIEValueAllocator;
354
355 /// Maps MDNode with its corresponding DwarfCompileUnit.
356 MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
357
358 /// Maps a CU DIE with its corresponding DwarfCompileUnit.
359 DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
360
361 /// List of all labels used in aranges generation.
362 std::vector<SymbolCU> ArangeLabels;
363
364 /// Size of each symbol emitted (for those symbols that have a specific size).
365 DenseMap<const MCSymbol *, uint64_t> SymSize;
366
367 /// Collection of abstract variables/labels.
368 SmallVector<std::unique_ptr<DbgEntity>, 64> ConcreteEntities;
369
370 /// Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
371 /// can refer to them in spite of insertions into this list.
372 DebugLocStream DebugLocs;
373
374 /// This is a collection of subprogram MDNodes that are processed to
375 /// create DIEs.
376 SmallSetVector<const DISubprogram *, 16> ProcessedSPNodes;
377
378 /// Map function-local imported entities to their parent local scope
379 /// (either DILexicalBlock or DISubprogram) for a processed function
380 /// (including inlined subprograms).
381 using MDNodeSet = SetVector<const MDNode *, SmallVector<const MDNode *, 2>,
382 SmallPtrSet<const MDNode *, 2>>;
383 DenseMap<const DILocalScope *, MDNodeSet> LocalDeclsPerLS;
384
385 /// If nonnull, stores the current machine function we're processing.
386 const MachineFunction *CurFn = nullptr;
387
388 /// If nonnull, stores the CU in which the previous subprogram was contained.
389 const DwarfCompileUnit *PrevCU = nullptr;
390
391 /// As an optimization, there is no need to emit an entry in the directory
392 /// table for the same directory as DW_AT_comp_dir.
393 StringRef CompilationDir;
394
395 /// Holder for the file specific debug information.
396 DwarfFile InfoHolder;
397
398 /// Holders for the various debug information flags that we might need to
399 /// have exposed. See accessor functions below for description.
400
401 /// Map from MDNodes for user-defined types to their type signatures. Also
402 /// used to keep track of which types we have emitted type units for.
403 DenseMap<const MDNode *, uint64_t> TypeSignatures;
404
405 DenseMap<const MCSection *, const MCSymbol *> SectionLabels;
406
407 SmallVector<
408 std::pair<std::unique_ptr<DwarfTypeUnit>, const DICompositeType *>, 1>
409 TypeUnitsUnderConstruction;
410
411 /// Used to set a uniqe ID for a Type Unit.
412 /// This counter represents number of DwarfTypeUnits created, not necessarily
413 /// number of type units that will be emitted.
414 unsigned NumTypeUnitsCreated = 0;
415
416 /// Whether to use the GNU TLS opcode (instead of the standard opcode).
417 bool UseGNUTLSOpcode;
418
419 /// Whether to use DWARF 2 bitfields (instead of the DWARF 4 format).
420 bool UseDWARF2Bitfields;
421
422 /// Whether to emit all linkage names, or just abstract subprograms.
423 bool UseAllLinkageNames;
424
425 /// Use inlined strings.
426 bool UseInlineStrings = false;
427
428 /// Allow emission of .debug_ranges section.
429 bool UseRangesSection = true;
430
431 /// True if the sections itself must be used as references and don't create
432 /// temp symbols inside DWARF sections.
433 bool UseSectionsAsReferences = false;
434
435 ///Allow emission of the .debug_loc section.
436 bool UseLocSection = true;
437
438 /// Generate DWARF v4 type units.
439 bool GenerateTypeUnits;
440
441 /// Emit a .debug_macro section instead of .debug_macinfo.
442 bool UseDebugMacroSection;
443
444 /// Avoid using DW_OP_convert due to consumer incompatibilities.
445 bool EnableOpConvert;
446
447public:
448 enum class MinimizeAddrInV5 {
449 Default,
450 Disabled,
451 Ranges,
452 Expressions,
453 Form,
454 };
455
456 enum class DWARF5AccelTableKind {
457 CU = 0,
458 TU = 1,
459 };
460
461private:
462 /// Force the use of DW_AT_ranges even for single-entry range lists.
463 MinimizeAddrInV5 MinimizeAddr = MinimizeAddrInV5::Disabled;
464
465 /// DWARF5 Experimental Options
466 /// @{
467 AccelTableKind TheAccelTableKind;
468 bool HasAppleExtensionAttributes;
469 bool HasSplitDwarf;
470
471 /// Whether to generate the DWARF v5 string offsets table.
472 /// It consists of a series of contributions, each preceded by a header.
473 /// The pre-DWARF v5 string offsets table for split dwarf is, in contrast,
474 /// a monolithic sequence of string offsets.
475 bool UseSegmentedStringOffsetsTable;
476
477 /// Enable production of call site parameters needed to print the debug entry
478 /// values. Useful for testing purposes when a debugger does not support the
479 /// feature yet.
480 bool EmitDebugEntryValues;
481
482 /// Separated Dwarf Variables
483 /// In general these will all be for bits that are left in the
484 /// original object file, rather than things that are meant
485 /// to be in the .dwo sections.
486
487 /// Holder for the skeleton information.
488 DwarfFile SkeletonHolder;
489
490 /// Store file names for type units under fission in a line table
491 /// header that will be emitted into debug_line.dwo.
492 // FIXME: replace this with a map from comp_dir to table so that we
493 // can emit multiple tables during LTO each of which uses directory
494 // 0, referencing the comp_dir of all the type units that use it.
495 MCDwarfDwoLineTable SplitTypeUnitFileTable;
496 /// @}
497
498 /// True iff there are multiple CUs in this module.
499 bool SingleCU;
500 bool IsDarwin;
501
502 /// Map for tracking Fortran deferred CHARACTER lengths.
503 DenseMap<const DIStringType *, unsigned> StringTypeLocMap;
504
505 AddressPool AddrPool;
506
507 /// Accelerator tables.
508 DWARF5AccelTable AccelDebugNames;
509 DWARF5AccelTable AccelTypeUnitsDebugNames;
510 /// Used to hide which DWARF5AccelTable we are using now.
511 DWARF5AccelTable *CurrentDebugNames = &AccelDebugNames;
512 AccelTable<AppleAccelTableOffsetData> AccelNames;
513 AccelTable<AppleAccelTableOffsetData> AccelObjC;
514 AccelTable<AppleAccelTableOffsetData> AccelNamespace;
515 AccelTable<AppleAccelTableTypeData> AccelTypes;
516
517 /// Identify a debugger for "tuning" the debug info.
518 ///
519 /// The "tuning" should be used to set defaults for individual feature flags
520 /// in DwarfDebug; if a given feature has a more specific command-line option,
521 /// that option should take precedence over the tuning.
522 DebuggerKind DebuggerTuning = DebuggerKind::Default;
523
524 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
525
526 const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
527 return InfoHolder.getUnits();
528 }
529
530 using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
531
532 void ensureAbstractEntityIsCreatedIfScoped(DwarfCompileUnit &CU,
533 const DINode *Node,
534 const MDNode *Scope);
535
536 DbgEntity *createConcreteEntity(DwarfCompileUnit &TheCU,
537 LexicalScope &Scope,
538 const DINode *Node,
539 const DILocation *Location,
540 const MCSymbol *Sym = nullptr);
541
542 /// Construct a DIE for this abstract scope.
543 void constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU, LexicalScope *Scope);
544
545 /// Construct DIEs for call site entries describing the calls in \p MF.
546 void constructCallSiteEntryDIEs(const DISubprogram &SP, DwarfCompileUnit &CU,
547 DIE &ScopeDIE, const MachineFunction &MF);
548
549 template <typename DataT>
550 void addAccelNameImpl(const DwarfUnit &Unit,
551 const DICompileUnit::DebugNameTableKind NameTableKind,
552 AccelTable<DataT> &AppleAccel, StringRef Name,
553 const DIE &Die);
554
555 void finishEntityDefinitions();
556
557 void finishSubprogramDefinitions();
558
559 /// Finish off debug information after all functions have been
560 /// processed.
561 void finalizeModuleInfo();
562
563 /// Emit the debug info section.
564 void emitDebugInfo();
565
566 /// Emit the abbreviation section.
567 void emitAbbreviations();
568
569 /// Emit the string offsets table header.
570 void emitStringOffsetsTableHeader();
571
572 /// Emit a specified accelerator table.
573 template <typename AccelTableT>
574 void emitAccel(AccelTableT &Accel, MCSection *Section, StringRef TableName);
575
576 /// Emit DWARF v5 accelerator table.
577 void emitAccelDebugNames();
578
579 /// Emit visible names into a hashed accelerator table section.
580 void emitAccelNames();
581
582 /// Emit objective C classes and categories into a hashed
583 /// accelerator table section.
584 void emitAccelObjC();
585
586 /// Emit namespace dies into a hashed accelerator table.
587 void emitAccelNamespaces();
588
589 /// Emit type dies into a hashed accelerator table.
590 void emitAccelTypes();
591
592 /// Emit visible names and types into debug pubnames and pubtypes sections.
593 void emitDebugPubSections();
594
595 void emitDebugPubSection(bool GnuStyle, StringRef Name,
596 DwarfCompileUnit *TheU,
597 const StringMap<const DIE *> &Globals);
598
599 /// Emit null-terminated strings into a debug str section.
600 void emitDebugStr();
601
602 /// Emit variable locations into a debug loc section.
603 void emitDebugLoc();
604
605 /// Emit variable locations into a debug loc dwo section.
606 void emitDebugLocDWO();
607
608 void emitDebugLocImpl(MCSection *Sec);
609
610 /// Emit address ranges into a debug aranges section.
611 void emitDebugARanges();
612
613 /// Emit address ranges into a debug ranges section.
614 void emitDebugRanges();
615 void emitDebugRangesDWO();
616 void emitDebugRangesImpl(const DwarfFile &Holder, MCSection *Section);
617
618 /// Emit macros into a debug macinfo section.
619 void emitDebugMacinfo();
620 /// Emit macros into a debug macinfo.dwo section.
621 void emitDebugMacinfoDWO();
622 void emitDebugMacinfoImpl(MCSection *Section);
623 void emitMacro(DIMacro &M);
624 void emitMacroFile(DIMacroFile &F, DwarfCompileUnit &U);
625 void emitMacroFileImpl(DIMacroFile &F, DwarfCompileUnit &U,
626 unsigned StartFile, unsigned EndFile,
627 StringRef (*MacroFormToString)(unsigned Form));
628 void handleMacroNodes(DIMacroNodeArray Nodes, DwarfCompileUnit &U);
629
630 /// DWARF 5 Experimental Split Dwarf Emitters
631
632 /// Initialize common features of skeleton units.
633 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
634 std::unique_ptr<DwarfCompileUnit> NewU);
635
636 /// Construct the split debug info compile unit for the debug info section.
637 /// In DWARF v5, the skeleton unit DIE may have the following attributes:
638 /// DW_AT_addr_base, DW_AT_comp_dir, DW_AT_dwo_name, DW_AT_high_pc,
639 /// DW_AT_low_pc, DW_AT_ranges, DW_AT_stmt_list, and DW_AT_str_offsets_base.
640 /// Prior to DWARF v5 it may also have DW_AT_GNU_dwo_id. DW_AT_GNU_dwo_name
641 /// is used instead of DW_AT_dwo_name, Dw_AT_GNU_addr_base instead of
642 /// DW_AT_addr_base, and DW_AT_GNU_ranges_base instead of DW_AT_rnglists_base.
643 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
644
645 /// Emit the debug info dwo section.
646 void emitDebugInfoDWO();
647
648 /// Emit the debug abbrev dwo section.
649 void emitDebugAbbrevDWO();
650
651 /// Emit the debug line dwo section.
652 void emitDebugLineDWO();
653
654 /// Emit the dwo stringoffsets table header.
655 void emitStringOffsetsTableHeaderDWO();
656
657 /// Emit the debug str dwo section.
658 void emitDebugStrDWO();
659
660 /// Emit DWO addresses.
661 void emitDebugAddr();
662
663 /// Flags to let the linker know we have emitted new style pubnames. Only
664 /// emit it here if we don't have a skeleton CU for split dwarf.
665 void addGnuPubAttributes(DwarfCompileUnit &U, DIE &D) const;
666
667 /// Create new DwarfCompileUnit for the given metadata node with tag
668 /// DW_TAG_compile_unit.
669 DwarfCompileUnit &getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit);
670 void finishUnitAttributes(const DICompileUnit *DIUnit,
671 DwarfCompileUnit &NewCU);
672
673 /// Register a source line with debug info. Returns the unique
674 /// label that was emitted and which provides correspondence to the
675 /// source line list.
676 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
677 unsigned Flags);
678
679 /// Populate LexicalScope entries with variables' info.
680 void collectEntityInfo(DwarfCompileUnit &TheCU, const DISubprogram *SP,
681 DenseSet<InlinedEntity> &ProcessedVars);
682
683 /// Build the location list for all DBG_VALUEs in the
684 /// function that describe the same variable. If the resulting
685 /// list has only one entry that is valid for entire variable's
686 /// scope return true.
687 bool buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
688 const DbgValueHistoryMap::Entries &Entries);
689
690 /// Collect variable information from the side table maintained by MF.
691 void collectVariableInfoFromMFTable(DwarfCompileUnit &TheCU,
692 DenseSet<InlinedEntity> &P);
693
694 /// Emit the reference to the section.
695 void emitSectionReference(const DwarfCompileUnit &CU);
696
697protected:
698 /// Gather pre-function debug information.
699 void beginFunctionImpl(const MachineFunction *MF) override;
700
701 /// Gather and emit post-function debug information.
702 void endFunctionImpl(const MachineFunction *MF) override;
703
704 /// Get Dwarf compile unit ID for line table.
705 unsigned getDwarfCompileUnitIDForLineTable(const DwarfCompileUnit &CU);
706
707 void skippedNonDebugFunction() override;
708
709public:
710 //===--------------------------------------------------------------------===//
711 // Main entry points.
712 //
713 DwarfDebug(AsmPrinter *A);
714
715 ~DwarfDebug() override;
716
717 /// Emit all Dwarf sections that should come prior to the
718 /// content.
719 void beginModule(Module *M) override;
720
721 /// Emit all Dwarf sections that should come after the content.
722 void endModule() override;
723
724 /// Emits inital debug location directive.
725 DebugLoc emitInitialLocDirective(const MachineFunction &MF, unsigned CUID);
726
727 /// Process beginning of an instruction.
728 void beginInstruction(const MachineInstr *MI) override;
729
730 /// Perform an MD5 checksum of \p Identifier and return the lower 64 bits.
731 static uint64_t makeTypeSignature(StringRef Identifier);
732
733 /// Add a DIE to the set of types that we're going to pull into
734 /// type units.
735 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
736 DIE &Die, const DICompositeType *CTy);
737
738 /// Add a label so that arange data can be generated for it.
739 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(x: SCU); }
740
741 /// For symbols that have a size designated (e.g. common symbols),
742 /// this tracks that size.
743 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
744 SymSize[Sym] = Size;
745 }
746
747 /// Returns whether we should emit all DW_AT_[MIPS_]linkage_name.
748 /// If not, we still might emit certain cases.
749 bool useAllLinkageNames() const { return UseAllLinkageNames; }
750
751 /// Returns whether to use DW_OP_GNU_push_tls_address, instead of the
752 /// standard DW_OP_form_tls_address opcode
753 bool useGNUTLSOpcode() const { return UseGNUTLSOpcode; }
754
755 /// Returns whether to use the DWARF2 format for bitfields instyead of the
756 /// DWARF4 format.
757 bool useDWARF2Bitfields() const { return UseDWARF2Bitfields; }
758
759 /// Returns whether to use inline strings.
760 bool useInlineStrings() const { return UseInlineStrings; }
761
762 /// Returns whether ranges section should be emitted.
763 bool useRangesSection() const { return UseRangesSection; }
764
765 /// Returns whether range encodings should be used for single entry range
766 /// lists.
767 bool alwaysUseRanges(const DwarfCompileUnit &) const;
768
769 // Returns whether novel exprloc addrx+offset encodings should be used to
770 // reduce debug_addr size.
771 bool useAddrOffsetExpressions() const {
772 return MinimizeAddr == MinimizeAddrInV5::Expressions;
773 }
774
775 // Returns whether addrx+offset LLVM extension form should be used to reduce
776 // debug_addr size.
777 bool useAddrOffsetForm() const {
778 return MinimizeAddr == MinimizeAddrInV5::Form;
779 }
780
781 /// Returns whether to use sections as labels rather than temp symbols.
782 bool useSectionsAsReferences() const {
783 return UseSectionsAsReferences;
784 }
785
786 /// Returns whether .debug_loc section should be emitted.
787 bool useLocSection() const { return UseLocSection; }
788
789 /// Returns whether to generate DWARF v4 type units.
790 bool generateTypeUnits() const { return GenerateTypeUnits; }
791
792 // Experimental DWARF5 features.
793
794 /// Returns what kind (if any) of accelerator tables to emit.
795 AccelTableKind getAccelTableKind() const { return TheAccelTableKind; }
796
797 /// Seet TheAccelTableKind
798 void setTheAccelTableKind(AccelTableKind K) { TheAccelTableKind = K; };
799
800 bool useAppleExtensionAttributes() const {
801 return HasAppleExtensionAttributes;
802 }
803
804 /// Returns whether or not to change the current debug info for the
805 /// split dwarf proposal support.
806 bool useSplitDwarf() const { return HasSplitDwarf; }
807
808 /// Returns whether to generate a string offsets table with (possibly shared)
809 /// contributions from each CU and type unit. This implies the use of
810 /// DW_FORM_strx* indirect references with DWARF v5 and beyond. Note that
811 /// DW_FORM_GNU_str_index is also an indirect reference, but it is used with
812 /// a pre-DWARF v5 implementation of split DWARF sections, which uses a
813 /// monolithic string offsets table.
814 bool useSegmentedStringOffsetsTable() const {
815 return UseSegmentedStringOffsetsTable;
816 }
817
818 bool emitDebugEntryValues() const {
819 return EmitDebugEntryValues;
820 }
821
822 bool useOpConvert() const {
823 return EnableOpConvert;
824 }
825
826 bool shareAcrossDWOCUs() const;
827
828 /// Returns the Dwarf Version.
829 uint16_t getDwarfVersion() const;
830
831 /// Returns a suitable DWARF form to represent a section offset, i.e.
832 /// * DW_FORM_sec_offset for DWARF version >= 4;
833 /// * DW_FORM_data8 for 64-bit DWARFv3;
834 /// * DW_FORM_data4 for 32-bit DWARFv3 and DWARFv2.
835 dwarf::Form getDwarfSectionOffsetForm() const;
836
837 /// Returns the previous CU that was being updated
838 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
839 void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
840
841 /// Terminate the line table by adding the last range label.
842 void terminateLineTable(const DwarfCompileUnit *CU);
843
844 /// Returns the entries for the .debug_loc section.
845 const DebugLocStream &getDebugLocs() const { return DebugLocs; }
846
847 /// Emit an entry for the debug loc section. This can be used to
848 /// handle an entry that's going to be emitted into the debug loc section.
849 void emitDebugLocEntry(ByteStreamer &Streamer,
850 const DebugLocStream::Entry &Entry,
851 const DwarfCompileUnit *CU);
852
853 /// Emit the location for a debug loc entry, including the size header.
854 void emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry,
855 const DwarfCompileUnit *CU);
856
857 void addSubprogramNames(const DwarfUnit &Unit,
858 const DICompileUnit::DebugNameTableKind NameTableKind,
859 const DISubprogram *SP, DIE &Die);
860
861 AddressPool &getAddressPool() { return AddrPool; }
862
863 void addAccelName(const DwarfUnit &Unit,
864 const DICompileUnit::DebugNameTableKind NameTableKind,
865 StringRef Name, const DIE &Die);
866
867 void addAccelObjC(const DwarfUnit &Unit,
868 const DICompileUnit::DebugNameTableKind NameTableKind,
869 StringRef Name, const DIE &Die);
870
871 void addAccelNamespace(const DwarfUnit &Unit,
872 const DICompileUnit::DebugNameTableKind NameTableKind,
873 StringRef Name, const DIE &Die);
874
875 void addAccelType(const DwarfUnit &Unit,
876 const DICompileUnit::DebugNameTableKind NameTableKind,
877 StringRef Name, const DIE &Die, char Flags);
878
879 const MachineFunction *getCurrentFunction() const { return CurFn; }
880
881 /// A helper function to check whether the DIE for a given Scope is
882 /// going to be null.
883 bool isLexicalScopeDIENull(LexicalScope *Scope);
884
885 /// Find the matching DwarfCompileUnit for the given CU DIE.
886 DwarfCompileUnit *lookupCU(const DIE *Die) { return CUDieMap.lookup(Val: Die); }
887 const DwarfCompileUnit *lookupCU(const DIE *Die) const {
888 return CUDieMap.lookup(Val: Die);
889 }
890
891 unsigned getStringTypeLoc(const DIStringType *ST) const {
892 return StringTypeLocMap.lookup(Val: ST);
893 }
894
895 void addStringTypeLoc(const DIStringType *ST, unsigned Loc) {
896 assert(ST);
897 if (Loc)
898 StringTypeLocMap[ST] = Loc;
899 }
900
901 /// \defgroup DebuggerTuning Predicates to tune DWARF for a given debugger.
902 ///
903 /// Returns whether we are "tuning" for a given debugger.
904 /// @{
905 bool tuneForGDB() const { return DebuggerTuning == DebuggerKind::GDB; }
906 bool tuneForLLDB() const { return DebuggerTuning == DebuggerKind::LLDB; }
907 bool tuneForSCE() const { return DebuggerTuning == DebuggerKind::SCE; }
908 bool tuneForDBX() const { return DebuggerTuning == DebuggerKind::DBX; }
909 /// @}
910
911 const MCSymbol *getSectionLabel(const MCSection *S);
912 void insertSectionLabel(const MCSymbol *S);
913
914 static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
915 const DbgValueLoc &Value,
916 DwarfExpression &DwarfExpr);
917
918 /// If the \p File has an MD5 checksum, return it as an MD5Result
919 /// allocated in the MCContext.
920 std::optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
921
922 MDNodeSet &getLocalDeclsForScope(const DILocalScope *S) {
923 return LocalDeclsPerLS[S];
924 }
925
926 /// Sets the current DWARF5AccelTable to use.
927 void setCurrentDWARF5AccelTable(const DWARF5AccelTableKind Kind) {
928 switch (Kind) {
929 case DWARF5AccelTableKind::CU:
930 CurrentDebugNames = &AccelDebugNames;
931 break;
932 case DWARF5AccelTableKind::TU:
933 CurrentDebugNames = &AccelTypeUnitsDebugNames;
934 }
935 }
936 /// Returns either CU or TU DWARF5AccelTable.
937 DWARF5AccelTable &getCurrentDWARF5AccelTable() { return *CurrentDebugNames; }
938};
939
940} // end namespace llvm
941
942#endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
943