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 SmallDenseSet<const MachineInstr *> ForceIsStmtInstrs;
386
387 /// If nonnull, stores the current machine function we're processing.
388 const MachineFunction *CurFn = nullptr;
389
390 /// If nonnull, stores the CU in which the previous subprogram was contained.
391 const DwarfCompileUnit *PrevCU = nullptr;
392
393 /// As an optimization, there is no need to emit an entry in the directory
394 /// table for the same directory as DW_AT_comp_dir.
395 StringRef CompilationDir;
396
397 /// Holder for the file specific debug information.
398 DwarfFile InfoHolder;
399
400 /// Holders for the various debug information flags that we might need to
401 /// have exposed. See accessor functions below for description.
402
403 /// Map from MDNodes for user-defined types to their type signatures. Also
404 /// used to keep track of which types we have emitted type units for.
405 DenseMap<const MDNode *, uint64_t> TypeSignatures;
406
407 DenseMap<const MCSection *, const MCSymbol *> SectionLabels;
408
409 SmallVector<
410 std::pair<std::unique_ptr<DwarfTypeUnit>, const DICompositeType *>, 1>
411 TypeUnitsUnderConstruction;
412
413 /// Symbol pointing to the current function's DWARF line table entries.
414 MCSymbol *FunctionLineTableLabel;
415
416 /// Used to set a uniqe ID for a Type Unit.
417 /// This counter represents number of DwarfTypeUnits created, not necessarily
418 /// number of type units that will be emitted.
419 unsigned NumTypeUnitsCreated = 0;
420
421 /// Whether to use the GNU TLS opcode (instead of the standard opcode).
422 bool UseGNUTLSOpcode;
423
424 /// Whether to use DWARF 2 bitfields (instead of the DWARF 4 format).
425 bool UseDWARF2Bitfields;
426
427 /// Whether to emit all linkage names, or just abstract subprograms.
428 bool UseAllLinkageNames;
429
430 /// Use inlined strings.
431 bool UseInlineStrings = false;
432
433 /// Allow emission of .debug_ranges section.
434 bool UseRangesSection = true;
435
436 /// True if the sections itself must be used as references and don't create
437 /// temp symbols inside DWARF sections.
438 bool UseSectionsAsReferences = false;
439
440 /// Allow emission of .debug_aranges section
441 bool UseARangesSection = false;
442
443 /// Generate DWARF v4 type units.
444 bool GenerateTypeUnits;
445
446 /// Emit a .debug_macro section instead of .debug_macinfo.
447 bool UseDebugMacroSection;
448
449 /// Avoid using DW_OP_convert due to consumer incompatibilities.
450 bool EnableOpConvert;
451
452public:
453 enum class MinimizeAddrInV5 {
454 Default,
455 Disabled,
456 Ranges,
457 Expressions,
458 Form,
459 };
460
461 enum class DWARF5AccelTableKind {
462 CU = 0,
463 TU = 1,
464 };
465
466private:
467 /// Instructions which should get is_stmt applied because they implement key
468 /// functionality for a source atom.
469 SmallDenseSet<const MachineInstr *> KeyInstructions;
470
471 /// Force the use of DW_AT_ranges even for single-entry range lists.
472 MinimizeAddrInV5 MinimizeAddr = MinimizeAddrInV5::Disabled;
473
474 /// DWARF5 Experimental Options
475 /// @{
476 AccelTableKind TheAccelTableKind;
477 bool HasAppleExtensionAttributes;
478 bool HasSplitDwarf;
479
480 /// Whether to generate the DWARF v5 string offsets table.
481 /// It consists of a series of contributions, each preceded by a header.
482 /// The pre-DWARF v5 string offsets table for split dwarf is, in contrast,
483 /// a monolithic sequence of string offsets.
484 bool UseSegmentedStringOffsetsTable;
485
486 /// Enable production of call site parameters needed to print the debug entry
487 /// values. Useful for testing purposes when a debugger does not support the
488 /// feature yet.
489 bool EmitDebugEntryValues;
490
491 /// Separated Dwarf Variables
492 /// In general these will all be for bits that are left in the
493 /// original object file, rather than things that are meant
494 /// to be in the .dwo sections.
495
496 /// Holder for the skeleton information.
497 DwarfFile SkeletonHolder;
498
499 /// Store file names for type units under fission in a line table
500 /// header that will be emitted into debug_line.dwo.
501 // FIXME: replace this with a map from comp_dir to table so that we
502 // can emit multiple tables during LTO each of which uses directory
503 // 0, referencing the comp_dir of all the type units that use it.
504 MCDwarfDwoLineTable SplitTypeUnitFileTable;
505 /// @}
506
507 /// True iff there are multiple CUs in this module.
508 bool SingleCU;
509 bool IsDarwin;
510
511 /// Map for tracking Fortran deferred CHARACTER lengths.
512 DenseMap<const DIStringType *, unsigned> StringTypeLocMap;
513
514 AddressPool AddrPool;
515
516 /// Accelerator tables.
517 DWARF5AccelTable AccelDebugNames;
518 DWARF5AccelTable AccelTypeUnitsDebugNames;
519 /// Used to hide which DWARF5AccelTable we are using now.
520 DWARF5AccelTable *CurrentDebugNames = &AccelDebugNames;
521 AccelTable<AppleAccelTableOffsetData> AccelNames;
522 AccelTable<AppleAccelTableOffsetData> AccelObjC;
523 AccelTable<AppleAccelTableOffsetData> AccelNamespace;
524 AccelTable<AppleAccelTableTypeData> AccelTypes;
525
526 /// Identify a debugger for "tuning" the debug info.
527 ///
528 /// The "tuning" should be used to set defaults for individual feature flags
529 /// in DwarfDebug; if a given feature has a more specific command-line option,
530 /// that option should take precedence over the tuning.
531 DebuggerKind DebuggerTuning = DebuggerKind::Default;
532
533 MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
534
535 const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
536 return InfoHolder.getUnits();
537 }
538
539 using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
540
541 void ensureAbstractEntityIsCreatedIfScoped(DwarfCompileUnit &CU,
542 const DINode *Node,
543 const MDNode *Scope);
544
545 DbgEntity *createConcreteEntity(DwarfCompileUnit &TheCU,
546 LexicalScope &Scope,
547 const DINode *Node,
548 const DILocation *Location,
549 const MCSymbol *Sym = nullptr);
550
551 /// Construct a DIE for this abstract scope.
552 void constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU, LexicalScope *Scope);
553
554 /// Construct DIEs for call site entries describing the calls in \p MF.
555 void constructCallSiteEntryDIEs(const DISubprogram &SP, DwarfCompileUnit &CU,
556 DIE &ScopeDIE, const MachineFunction &MF);
557
558 template <typename DataT>
559 void addAccelNameImpl(const DwarfUnit &Unit,
560 const DICompileUnit::DebugNameTableKind NameTableKind,
561 AccelTable<DataT> &AppleAccel, StringRef Name,
562 const DIE &Die);
563
564 void finishEntityDefinitions();
565
566 void finishSubprogramDefinitions();
567
568 /// Finish off debug information after all functions have been
569 /// processed.
570 void finalizeModuleInfo();
571
572 /// Emit the debug info section.
573 void emitDebugInfo();
574
575 /// Emit the abbreviation section.
576 void emitAbbreviations();
577
578 /// Emit the string offsets table header.
579 void emitStringOffsetsTableHeader();
580
581 /// Emit a specified accelerator table.
582 template <typename AccelTableT>
583 void emitAccel(AccelTableT &Accel, MCSection *Section, StringRef TableName);
584
585 /// Emit DWARF v5 accelerator table.
586 void emitAccelDebugNames();
587
588 /// Emit visible names into a hashed accelerator table section.
589 void emitAccelNames();
590
591 /// Emit objective C classes and categories into a hashed
592 /// accelerator table section.
593 void emitAccelObjC();
594
595 /// Emit namespace dies into a hashed accelerator table.
596 void emitAccelNamespaces();
597
598 /// Emit type dies into a hashed accelerator table.
599 void emitAccelTypes();
600
601 /// Emit visible names and types into debug pubnames and pubtypes sections.
602 void emitDebugPubSections();
603
604 void emitDebugPubSection(bool GnuStyle, StringRef Name,
605 DwarfCompileUnit *TheU,
606 const StringMap<const DIE *> &Globals);
607
608 /// Emit null-terminated strings into a debug str section.
609 void emitDebugStr();
610
611 /// Emit variable locations into a debug loc section.
612 void emitDebugLoc();
613
614 /// Emit variable locations into a debug loc dwo section.
615 void emitDebugLocDWO();
616
617 void emitDebugLocImpl(MCSection *Sec);
618
619 /// Emit address ranges into a debug aranges section.
620 void emitDebugARanges();
621
622 /// Emit address ranges into a debug ranges section.
623 void emitDebugRanges();
624 void emitDebugRangesDWO();
625 void emitDebugRangesImpl(const DwarfFile &Holder, MCSection *Section);
626
627 /// Emit macros into a debug macinfo section.
628 void emitDebugMacinfo();
629 /// Emit macros into a debug macinfo.dwo section.
630 void emitDebugMacinfoDWO();
631 void emitDebugMacinfoImpl(MCSection *Section);
632 void emitMacro(DIMacro &M);
633 void emitMacroFile(DIMacroFile &F, DwarfCompileUnit &U);
634 void emitMacroFileImpl(DIMacroFile &F, DwarfCompileUnit &U,
635 unsigned StartFile, unsigned EndFile,
636 StringRef (*MacroFormToString)(unsigned Form));
637 void handleMacroNodes(DIMacroNodeArray Nodes, DwarfCompileUnit &U);
638
639 /// DWARF 5 Experimental Split Dwarf Emitters
640
641 /// Initialize common features of skeleton units.
642 void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
643 std::unique_ptr<DwarfCompileUnit> NewU);
644
645 /// Construct the split debug info compile unit for the debug info section.
646 /// In DWARF v5, the skeleton unit DIE may have the following attributes:
647 /// DW_AT_addr_base, DW_AT_comp_dir, DW_AT_dwo_name, DW_AT_high_pc,
648 /// DW_AT_low_pc, DW_AT_ranges, DW_AT_stmt_list, and DW_AT_str_offsets_base.
649 /// Prior to DWARF v5 it may also have DW_AT_GNU_dwo_id. DW_AT_GNU_dwo_name
650 /// is used instead of DW_AT_dwo_name, Dw_AT_GNU_addr_base instead of
651 /// DW_AT_addr_base, and DW_AT_GNU_ranges_base instead of DW_AT_rnglists_base.
652 DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
653
654 /// Emit the debug info dwo section.
655 void emitDebugInfoDWO();
656
657 /// Emit the debug abbrev dwo section.
658 void emitDebugAbbrevDWO();
659
660 /// Emit the debug line dwo section.
661 void emitDebugLineDWO();
662
663 /// Emit the dwo stringoffsets table header.
664 void emitStringOffsetsTableHeaderDWO();
665
666 /// Emit the debug str dwo section.
667 void emitDebugStrDWO();
668
669 /// Emit DWO addresses.
670 void emitDebugAddr();
671
672 /// Flags to let the linker know we have emitted new style pubnames. Only
673 /// emit it here if we don't have a skeleton CU for split dwarf.
674 void addGnuPubAttributes(DwarfCompileUnit &U, DIE &D) const;
675
676 /// Create new DwarfCompileUnit for the given metadata node with tag
677 /// DW_TAG_compile_unit.
678 DwarfCompileUnit &getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit);
679 void finishUnitAttributes(const DICompileUnit *DIUnit,
680 DwarfCompileUnit &NewCU);
681
682 /// Register a source line with debug info. Returns the unique
683 /// label that was emitted and which provides correspondence to the
684 /// source line list.
685 void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
686 unsigned Flags, StringRef Location = {});
687
688 /// Populate LexicalScope entries with variables' info.
689 void collectEntityInfo(DwarfCompileUnit &TheCU, const DISubprogram *SP,
690 DenseSet<InlinedEntity> &ProcessedVars);
691
692 /// Build the location list for all DBG_VALUEs in the
693 /// function that describe the same variable. If the resulting
694 /// list has only one entry that is valid for entire variable's
695 /// scope return true.
696 bool buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
697 const DbgValueHistoryMap::Entries &Entries);
698
699 /// Collect variable information from the side table maintained by MF.
700 void collectVariableInfoFromMFTable(DwarfCompileUnit &TheCU,
701 DenseSet<InlinedEntity> &P);
702
703 /// Emit the reference to the section.
704 void emitSectionReference(const DwarfCompileUnit &CU);
705
706 void findForceIsStmtInstrs(const MachineFunction *MF);
707
708 /// Compute instructions which should get is_stmt applied because they
709 /// implement key functionality for a source location atom, store results in
710 /// DwarfDebug::KeyInstructions.
711 void computeKeyInstructions(const MachineFunction *MF);
712
713protected:
714 /// Gather pre-function debug information.
715 void beginFunctionImpl(const MachineFunction *MF) override;
716
717 /// Gather and emit post-function debug information.
718 void endFunctionImpl(const MachineFunction *MF) override;
719
720 /// Get Dwarf compile unit ID for line table.
721 unsigned getDwarfCompileUnitIDForLineTable(const DwarfCompileUnit &CU);
722
723 void skippedNonDebugFunction() override;
724
725public:
726 //===--------------------------------------------------------------------===//
727 // Main entry points.
728 //
729 DwarfDebug(AsmPrinter *A);
730
731 ~DwarfDebug() override;
732
733 /// Emit all Dwarf sections that should come prior to the
734 /// content.
735 void beginModule(Module *M) override;
736
737 /// Emit all Dwarf sections that should come after the content.
738 void endModule() override;
739
740 /// Emits inital debug location directive. Returns instruction at which
741 /// the function prologue ends.
742 const MachineInstr *emitInitialLocDirective(const MachineFunction &MF,
743 unsigned CUID);
744
745 /// Process beginning of an instruction.
746 void beginInstruction(const MachineInstr *MI) override;
747
748 /// Process beginning of code alignment.
749 void beginCodeAlignment(const MachineBasicBlock &MBB) override;
750
751 /// Perform an MD5 checksum of \p Identifier and return the lower 64 bits.
752 static uint64_t makeTypeSignature(StringRef Identifier);
753
754 /// Add a DIE to the set of types that we're going to pull into
755 /// type units.
756 void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
757 DIE &Die, const DICompositeType *CTy);
758
759 /// Add a label so that arange data can be generated for it.
760 void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(x: SCU); }
761
762 /// For symbols that have a size designated (e.g. common symbols),
763 /// this tracks that size.
764 void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
765 SymSize[Sym] = Size;
766 }
767
768 /// Returns whether we should emit all DW_AT_[MIPS_]linkage_name.
769 /// If not, we still might emit certain cases.
770 bool useAllLinkageNames() const { return UseAllLinkageNames; }
771
772 /// Returns whether to use DW_OP_GNU_push_tls_address, instead of the
773 /// standard DW_OP_form_tls_address opcode
774 bool useGNUTLSOpcode() const { return UseGNUTLSOpcode; }
775
776 /// Returns whether to use the DWARF2 format for bitfields instyead of the
777 /// DWARF4 format.
778 bool useDWARF2Bitfields() const { return UseDWARF2Bitfields; }
779
780 /// Returns whether to use inline strings.
781 bool useInlineStrings() const { return UseInlineStrings; }
782
783 /// Returns whether ranges section should be emitted.
784 bool useRangesSection() const { return UseRangesSection; }
785
786 /// Returns whether range encodings should be used for single entry range
787 /// lists.
788 bool alwaysUseRanges(const DwarfCompileUnit &) const;
789
790 // Returns whether novel exprloc addrx+offset encodings should be used to
791 // reduce debug_addr size.
792 bool useAddrOffsetExpressions() const {
793 return MinimizeAddr == MinimizeAddrInV5::Expressions;
794 }
795
796 // Returns whether addrx+offset LLVM extension form should be used to reduce
797 // debug_addr size.
798 bool useAddrOffsetForm() const {
799 return MinimizeAddr == MinimizeAddrInV5::Form;
800 }
801
802 /// Returns whether to use sections as labels rather than temp symbols.
803 bool useSectionsAsReferences() const {
804 return UseSectionsAsReferences;
805 }
806
807 /// Returns whether to generate DWARF v4 type units.
808 bool generateTypeUnits() const { return GenerateTypeUnits; }
809
810 // Experimental DWARF5 features.
811
812 /// Returns what kind (if any) of accelerator tables to emit.
813 AccelTableKind getAccelTableKind() const { return TheAccelTableKind; }
814
815 /// Seet TheAccelTableKind
816 void setTheAccelTableKind(AccelTableKind K) { TheAccelTableKind = K; };
817
818 bool useAppleExtensionAttributes() const {
819 return HasAppleExtensionAttributes;
820 }
821
822 /// Returns whether or not to change the current debug info for the
823 /// split dwarf proposal support.
824 bool useSplitDwarf() const { return HasSplitDwarf; }
825
826 /// Returns whether to generate a string offsets table with (possibly shared)
827 /// contributions from each CU and type unit. This implies the use of
828 /// DW_FORM_strx* indirect references with DWARF v5 and beyond. Note that
829 /// DW_FORM_GNU_str_index is also an indirect reference, but it is used with
830 /// a pre-DWARF v5 implementation of split DWARF sections, which uses a
831 /// monolithic string offsets table.
832 bool useSegmentedStringOffsetsTable() const {
833 return UseSegmentedStringOffsetsTable;
834 }
835
836 bool emitDebugEntryValues() const {
837 return EmitDebugEntryValues;
838 }
839
840 bool useOpConvert() const {
841 return EnableOpConvert;
842 }
843
844 bool shareAcrossDWOCUs() const;
845
846 /// Returns the Dwarf Version.
847 uint16_t getDwarfVersion() const;
848
849 /// Returns a suitable DWARF form to represent a section offset, i.e.
850 /// * DW_FORM_sec_offset for DWARF version >= 4;
851 /// * DW_FORM_data8 for 64-bit DWARFv3;
852 /// * DW_FORM_data4 for 32-bit DWARFv3 and DWARFv2.
853 dwarf::Form getDwarfSectionOffsetForm() const;
854
855 /// Returns the previous CU that was being updated
856 const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
857 void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
858
859 /// Terminate the line table by adding the last range label.
860 void terminateLineTable(const DwarfCompileUnit *CU);
861
862 /// Returns the entries for the .debug_loc section.
863 const DebugLocStream &getDebugLocs() const { return DebugLocs; }
864
865 /// Emit an entry for the debug loc section. This can be used to
866 /// handle an entry that's going to be emitted into the debug loc section.
867 void emitDebugLocEntry(ByteStreamer &Streamer,
868 const DebugLocStream::Entry &Entry,
869 const DwarfCompileUnit *CU);
870
871 /// Emit the location for a debug loc entry, including the size header.
872 void emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry,
873 const DwarfCompileUnit *CU);
874
875 void addSubprogramNames(const DwarfUnit &Unit,
876 const DICompileUnit::DebugNameTableKind NameTableKind,
877 const DISubprogram *SP, DIE &Die);
878
879 AddressPool &getAddressPool() { return AddrPool; }
880
881 void addAccelName(const DwarfUnit &Unit,
882 const DICompileUnit::DebugNameTableKind NameTableKind,
883 StringRef Name, const DIE &Die);
884
885 void addAccelObjC(const DwarfUnit &Unit,
886 const DICompileUnit::DebugNameTableKind NameTableKind,
887 StringRef Name, const DIE &Die);
888
889 void addAccelNamespace(const DwarfUnit &Unit,
890 const DICompileUnit::DebugNameTableKind NameTableKind,
891 StringRef Name, const DIE &Die);
892
893 void addAccelType(const DwarfUnit &Unit,
894 const DICompileUnit::DebugNameTableKind NameTableKind,
895 StringRef Name, const DIE &Die, char Flags);
896
897 const MachineFunction *getCurrentFunction() const { return CurFn; }
898
899 /// A helper function to check whether the DIE for a given Scope is
900 /// going to be null.
901 bool isLexicalScopeDIENull(LexicalScope *Scope);
902
903 /// Find the matching DwarfCompileUnit for the given CU DIE.
904 DwarfCompileUnit *lookupCU(const DIE *Die) { return CUDieMap.lookup(Val: Die); }
905 const DwarfCompileUnit *lookupCU(const DIE *Die) const {
906 return CUDieMap.lookup(Val: Die);
907 }
908
909 unsigned getStringTypeLoc(const DIStringType *ST) const {
910 return StringTypeLocMap.lookup(Val: ST);
911 }
912
913 void addStringTypeLoc(const DIStringType *ST, unsigned Loc) {
914 assert(ST);
915 if (Loc)
916 StringTypeLocMap[ST] = Loc;
917 }
918
919 /// \defgroup DebuggerTuning Predicates to tune DWARF for a given debugger.
920 ///
921 /// Returns whether we are "tuning" for a given debugger.
922 /// @{
923 bool tuneForGDB() const { return DebuggerTuning == DebuggerKind::GDB; }
924 bool tuneForLLDB() const { return DebuggerTuning == DebuggerKind::LLDB; }
925 bool tuneForSCE() const { return DebuggerTuning == DebuggerKind::SCE; }
926 bool tuneForDBX() const { return DebuggerTuning == DebuggerKind::DBX; }
927 /// @}
928
929 const MCSymbol *getSectionLabel(const MCSection *S);
930 void insertSectionLabel(const MCSymbol *S);
931
932 static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
933 const DbgValueLoc &Value,
934 DwarfExpression &DwarfExpr);
935
936 /// If the \p File has an MD5 checksum, return it as an MD5Result
937 /// allocated in the MCContext.
938 std::optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
939
940 MDNodeSet &getLocalDeclsForScope(const DILocalScope *S) {
941 return LocalDeclsPerLS[S];
942 }
943
944 /// Sets the current DWARF5AccelTable to use.
945 void setCurrentDWARF5AccelTable(const DWARF5AccelTableKind Kind) {
946 switch (Kind) {
947 case DWARF5AccelTableKind::CU:
948 CurrentDebugNames = &AccelDebugNames;
949 break;
950 case DWARF5AccelTableKind::TU:
951 CurrentDebugNames = &AccelTypeUnitsDebugNames;
952 }
953 }
954 /// Returns either CU or TU DWARF5AccelTable.
955 DWARF5AccelTable &getCurrentDWARF5AccelTable() { return *CurrentDebugNames; }
956};
957
958} // end namespace llvm
959
960#endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
961