1//===-- llvm/CodeGen/DwarfUnit.h - Dwarf Compile Unit ---*- 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 compile unit.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFUNIT_H
14#define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFUNIT_H
15
16#include "DwarfDebug.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/CodeGen/AsmPrinter.h"
19#include "llvm/CodeGen/DIE.h"
20#include "llvm/Target/TargetMachine.h"
21#include <optional>
22#include <string>
23
24namespace llvm {
25
26class ConstantFP;
27class ConstantInt;
28class DwarfCompileUnit;
29class MCDwarfDwoLineTable;
30class MCSymbol;
31
32//===----------------------------------------------------------------------===//
33/// This dwarf writer support class manages information associated with a
34/// source file.
35class DwarfUnit : public DIEUnit {
36protected:
37 /// A numeric ID unique among all CUs in the module
38 unsigned UniqueID;
39 /// MDNode for the compile unit.
40 const DICompileUnit *CUNode;
41
42 // All DIEValues are allocated through this allocator.
43 BumpPtrAllocator DIEValueAllocator;
44
45 /// Target of Dwarf emission.
46 AsmPrinter *Asm;
47
48 /// The start of the unit within its section.
49 MCSymbol *LabelBegin = nullptr;
50
51 /// Emitted at the end of the CU and used to compute the CU Length field.
52 MCSymbol *EndLabel = nullptr;
53
54 // Holders for some common dwarf information.
55 DwarfDebug *DD;
56 DwarfFile *DU;
57
58 /// An anonymous type for index type. Owned by DIEUnit.
59 DIE *IndexTyDie = nullptr;
60
61 /// Tracks the mapping of unit level debug information variables to debug
62 /// information entries.
63 DenseMap<const MDNode *, DIE *> MDNodeToDieMap;
64
65 /// A list of all the DIEBlocks in use.
66 std::vector<DIEBlock *> DIEBlocks;
67
68 /// A list of all the DIELocs in use.
69 std::vector<DIELoc *> DIELocs;
70
71 /// This map is used to keep track of subprogram DIEs that need
72 /// DW_AT_containing_type attribute. This attribute points to a DIE that
73 /// corresponds to the MDNode mapped with the subprogram DIE.
74 DenseMap<DIE *, const DINode *> ContainingTypeMap;
75
76 DwarfUnit(dwarf::Tag, const DICompileUnit *Node, AsmPrinter *A,
77 DwarfDebug *DW, DwarfFile *DWU, unsigned UniqueID = 0);
78
79 bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie, bool Minimal);
80
81 bool isShareableAcrossCUs(const DINode *D) const;
82
83 template <typename T>
84 void addAttribute(DIEValueList &Die, dwarf::Attribute Attribute,
85 dwarf::Form Form, T &&Value) {
86 // For strict DWARF mode, only generate attributes available to current
87 // DWARF version.
88 // Attribute 0 is used when emitting form-encoded values in blocks, which
89 // don't have attributes (only forms) so we cannot detect their DWARF
90 // version compatibility here and assume they are compatible.
91 if (Attribute != 0 && Asm->TM.Options.DebugStrictDwarf &&
92 DD->getDwarfVersion() < dwarf::AttributeVersion(A: Attribute))
93 return;
94
95 Die.addValue(Alloc&: DIEValueAllocator,
96 V: DIEValue(Attribute, Form, std::forward<T>(Value)));
97 }
98
99public:
100 /// Gets Unique ID for this unit.
101 unsigned getUniqueID() const { return UniqueID; }
102 // Accessors.
103 AsmPrinter* getAsmPrinter() const { return Asm; }
104 /// Get the the symbol for start of the section for this unit.
105 MCSymbol *getLabelBegin() const {
106 assert(LabelBegin && "LabelBegin is not initialized");
107 return LabelBegin;
108 }
109 MCSymbol *getEndLabel() const { return EndLabel; }
110 uint16_t getLanguage() const { return CUNode->getSourceLanguage(); }
111 const DICompileUnit *getCUNode() const { return CUNode; }
112 DwarfDebug &getDwarfDebug() const { return *DD; }
113
114 /// Return true if this compile unit has something to write out.
115 bool hasContent() const { return getUnitDie().hasChildren(); }
116
117 /// Get string containing language specific context for a global name.
118 ///
119 /// Walks the metadata parent chain in a language specific manner (using the
120 /// compile unit language) and returns it as a string. This is done at the
121 /// metadata level because DIEs may not currently have been added to the
122 /// parent context and walking the DIEs looking for names is more expensive
123 /// than walking the metadata.
124 std::string getParentContextString(const DIScope *Context) const;
125
126 /// Add a new global name to the compile unit.
127 virtual void addGlobalName(StringRef Name, const DIE &Die,
128 const DIScope *Context) = 0;
129
130 /// Add a new global type to the compile unit.
131 virtual void addGlobalTypeImpl(const DIType *Ty, const DIE &Die,
132 const DIScope *Context) = 0;
133
134 void addGlobalType(const DIType *Ty, const DIE &Die, const DIScope *Context);
135
136 /// Returns the DIE map slot for the specified debug variable.
137 ///
138 /// We delegate the request to DwarfDebug when the MDNode can be part of the
139 /// type system, since DIEs for the type system can be shared across CUs and
140 /// the mappings are kept in DwarfDebug.
141 DIE *getDIE(const DINode *D) const;
142
143 /// Returns a fresh newly allocated DIELoc.
144 DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; }
145
146 /// Insert DIE into the map.
147 ///
148 /// We delegate the request to DwarfDebug when the MDNode can be part of the
149 /// type system, since DIEs for the type system can be shared across CUs and
150 /// the mappings are kept in DwarfDebug.
151 void insertDIE(const DINode *Desc, DIE *D);
152
153 void insertDIE(DIE *D);
154
155 /// Add a flag that is true to the DIE.
156 void addFlag(DIE &Die, dwarf::Attribute Attribute);
157
158 /// Add an unsigned integer attribute data and value.
159 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute,
160 std::optional<dwarf::Form> Form, uint64_t Integer);
161
162 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer);
163
164 /// Add an signed integer attribute data and value.
165 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute,
166 std::optional<dwarf::Form> Form, int64_t Integer);
167
168 void addSInt(DIEValueList &Die, std::optional<dwarf::Form> Form,
169 int64_t Integer);
170
171 /// Add an integer attribute data and value; value may be any width.
172 void addInt(DIE &Die, dwarf::Attribute Attribute, const APInt &Integer,
173 bool Unsigned);
174
175 /// Add a string attribute data and value.
176 ///
177 /// We always emit a reference to the string pool instead of immediate
178 /// strings so that DIEs have more predictable sizes. In the case of split
179 /// dwarf we emit an index into another table which gets us the static offset
180 /// into the string table.
181 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
182
183 /// Add a Dwarf label attribute data and value.
184 void addLabel(DIEValueList &Die, dwarf::Attribute Attribute, dwarf::Form Form,
185 const MCSymbol *Label);
186
187 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label);
188
189 /// Add an offset into a section attribute data and value.
190 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer);
191
192 /// Add a dwarf op address data and value using the form given and an
193 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
194 void addOpAddress(DIELoc &Die, const MCSymbol *Sym);
195 void addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label);
196
197 /// Add a label delta attribute data and value.
198 void addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute,
199 const MCSymbol *Hi, const MCSymbol *Lo);
200
201 /// Add a DIE attribute data and value.
202 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry);
203
204 /// Add a DIE attribute data and value.
205 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
206
207 /// Add a type's DW_AT_signature and set the declaration flag.
208 void addDIETypeSignature(DIE &Die, uint64_t Signature);
209
210 /// Add block data.
211 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc);
212
213 /// Add block data.
214 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block);
215 void addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form,
216 DIEBlock *Block);
217
218 /// Add location information to specified debug information entry.
219 void addSourceLine(DIE &Die, unsigned Line, unsigned Column,
220 const DIFile *File);
221 void addSourceLine(DIE &Die, const DILocalVariable *V);
222 void addSourceLine(DIE &Die, const DIGlobalVariable *G);
223 void addSourceLine(DIE &Die, const DISubprogram *SP);
224 void addSourceLine(DIE &Die, const DILabel *L);
225 void addSourceLine(DIE &Die, const DIType *Ty);
226 void addSourceLine(DIE &Die, const DIObjCProperty *Ty);
227
228 /// Add constant value entry in variable DIE.
229 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty);
230 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty);
231 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned);
232 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty);
233 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val);
234
235 /// Add constant value entry in variable DIE.
236 void addConstantFPValue(DIE &Die, const ConstantFP *CFP);
237
238 /// Add a linkage name, if it isn't empty.
239 void addLinkageName(DIE &Die, StringRef LinkageName);
240
241 /// Add template parameters in buffer.
242 void addTemplateParams(DIE &Buffer, DINodeArray TParams);
243
244 /// Add thrown types.
245 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes);
246
247 /// Add the accessibility attribute.
248 void addAccess(DIE &Die, DINode::DIFlags Flags);
249
250 /// Add a new type attribute to the specified entity.
251 ///
252 /// This takes and attribute parameter because DW_AT_friend attributes are
253 /// also type references.
254 void addType(DIE &Entity, const DIType *Ty,
255 dwarf::Attribute Attribute = dwarf::DW_AT_type);
256
257 DIE *getOrCreateNameSpace(const DINamespace *NS);
258 DIE *getOrCreateModule(const DIModule *M);
259 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false);
260
261 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
262 bool SkipSPAttributes = false);
263
264 /// Creates type DIE with specific context.
265 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty);
266
267 /// Find existing DIE or create new DIE for the given type.
268 virtual DIE *getOrCreateTypeDIE(const MDNode *TyNode);
269
270 /// Get context owner's DIE.
271 virtual DIE *getOrCreateContextDIE(const DIScope *Context);
272
273 /// Construct DIEs for types that contain vtables.
274 void constructContainingTypeDIEs();
275
276 /// Construct function argument DIEs.
277 ///
278 /// \returns The index of the object parameter in \c Args if one exists.
279 /// Returns std::nullopt otherwise.
280 std::optional<unsigned> constructSubprogramArguments(DIE &Buffer,
281 DITypeRefArray Args);
282
283 /// Create a DIE with the given Tag, add the DIE to its parent, and
284 /// call insertDIE if MD is not null.
285 DIE &createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N = nullptr);
286
287 bool useSegmentedStringOffsetsTable() const {
288 return DD->useSegmentedStringOffsetsTable();
289 }
290
291 /// Compute the size of a header for this unit, not including the initial
292 /// length field.
293 virtual unsigned getHeaderSize() const {
294 return sizeof(int16_t) + // DWARF version number
295 Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section
296 sizeof(int8_t) + // Pointer Size (in bytes)
297 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t)
298 : 0); // DWARF v5 unit type
299 }
300
301 /// Emit the header for this unit, not including the initial length field.
302 virtual void emitHeader(bool UseOffsets) = 0;
303
304 /// Add the DW_AT_str_offsets_base attribute to the unit DIE.
305 void addStringOffsetsStart();
306
307 /// Add the DW_AT_rnglists_base attribute to the unit DIE.
308 void addRnglistsBase();
309
310 virtual DwarfCompileUnit &getCU() = 0;
311
312 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);
313
314 /// addSectionDelta - Add a label delta attribute data and value.
315 void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
316 const MCSymbol *Lo);
317
318 /// Add a Dwarf section label attribute data and value.
319 void addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
320 const MCSymbol *Label, const MCSymbol *Sec);
321
322 /// Add DW_TAG_LLVM_annotation.
323 void addAnnotation(DIE &Buffer, DINodeArray Annotations);
324
325 /// Get context owner's DIE.
326 DIE *createTypeDIE(const DICompositeType *Ty);
327
328 /// If this is a named finished type then include it in the list of types for
329 /// the accelerator tables.
330 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,
331 const DIE &TyDIE);
332
333protected:
334 ~DwarfUnit();
335
336 /// Create new static data member DIE.
337 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
338
339 /// Look up the source ID for the given file. If none currently exists,
340 /// create a new ID and insert it in the line table.
341 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0;
342
343 /// Emit the common part of the header for this unit.
344 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT);
345
346private:
347 /// A helper to add a wide integer constant to a DIE using a block
348 /// form.
349 void addIntAsBlock(DIE &Die, dwarf::Attribute Attribute, const APInt &Val);
350
351 // Add discriminant constants to a DW_TAG_variant DIE.
352 void addDiscriminant(DIE &Variant, Constant *Discriminant, bool IsUnsigned);
353
354 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
355 void constructTypeDIE(DIE &Buffer, const DIFixedPointType *BTy);
356 void constructTypeDIE(DIE &Buffer, const DIStringType *BTy);
357 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
358 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy);
359 void constructSubrangeDIE(DIE &Buffer, const DISubrangeType *SR,
360 bool ForArray = false);
361 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR);
362 void constructGenericSubrangeDIE(DIE &Buffer, const DIGenericSubrange *SR);
363 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy);
364 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy);
365 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT);
366 void constructTemplateTypeParameterDIE(DIE &Buffer,
367 const DITemplateTypeParameter *TP);
368 void constructTemplateValueParameterDIE(DIE &Buffer,
369 const DITemplateValueParameter *TVP);
370
371 /// Return the default lower bound for an array.
372 ///
373 /// If the DWARF version doesn't handle the language, return -1.
374 int64_t getDefaultLowerBound() const;
375
376 /// Get an anonymous type for index type.
377 DIE *getIndexTyDie();
378
379 /// Set D as anonymous type for index which can be reused later.
380 void setIndexTyDie(DIE *D) { IndexTyDie = D; }
381
382 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0;
383
384 virtual bool isDwoUnit() const = 0;
385 const MCSymbol *getCrossSectionRelativeBaseAddress() const override;
386
387 /// Returns 'true' if the current DwarfVersion is compatible
388 /// with the specified \p Version.
389 bool isCompatibleWithVersion(uint16_t Version) const;
390};
391
392class DwarfTypeUnit final : public DwarfUnit {
393 uint64_t TypeSignature;
394 const DIE *Ty;
395 DwarfCompileUnit &CU;
396 MCDwarfDwoLineTable *SplitLineTable;
397 bool UsedLineTable = false;
398
399 unsigned getOrCreateSourceID(const DIFile *File) override;
400 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
401 bool isDwoUnit() const override;
402
403public:
404 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW,
405 DwarfFile *DWU, unsigned UniqueID,
406 MCDwarfDwoLineTable *SplitLineTable = nullptr);
407
408 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
409 /// Returns Type Signature.
410 uint64_t getTypeSignature() const { return TypeSignature; }
411 void setType(const DIE *Ty) { this->Ty = Ty; }
412
413 /// Emit the header for this unit, not including the initial length field.
414 void emitHeader(bool UseOffsets) override;
415 unsigned getHeaderSize() const override {
416 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature
417 Asm->getDwarfOffsetByteSize(); // Type DIE Offset
418 }
419 void addGlobalName(StringRef Name, const DIE &Die,
420 const DIScope *Context) override;
421 void addGlobalTypeImpl(const DIType *Ty, const DIE &Die,
422 const DIScope *Context) override;
423 DwarfCompileUnit &getCU() override { return CU; }
424};
425} // end llvm namespace
426#endif
427