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(DIELoc &Die, std::optional<dwarf::Form> Form, int64_t Integer);
169
170 /// Add a string attribute data and value.
171 ///
172 /// We always emit a reference to the string pool instead of immediate
173 /// strings so that DIEs have more predictable sizes. In the case of split
174 /// dwarf we emit an index into another table which gets us the static offset
175 /// into the string table.
176 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
177
178 /// Add a Dwarf label attribute data and value.
179 void addLabel(DIEValueList &Die, dwarf::Attribute Attribute, dwarf::Form Form,
180 const MCSymbol *Label);
181
182 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label);
183
184 /// Add an offset into a section attribute data and value.
185 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer);
186
187 /// Add a dwarf op address data and value using the form given and an
188 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
189 void addOpAddress(DIELoc &Die, const MCSymbol *Sym);
190 void addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label);
191
192 /// Add a label delta attribute data and value.
193 void addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute,
194 const MCSymbol *Hi, const MCSymbol *Lo);
195
196 /// Add a DIE attribute data and value.
197 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry);
198
199 /// Add a DIE attribute data and value.
200 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
201
202 /// Add a type's DW_AT_signature and set the declaration flag.
203 void addDIETypeSignature(DIE &Die, uint64_t Signature);
204
205 /// Add block data.
206 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc);
207
208 /// Add block data.
209 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block);
210 void addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form,
211 DIEBlock *Block);
212
213 /// Add location information to specified debug information entry.
214 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File);
215 void addSourceLine(DIE &Die, const DILocalVariable *V);
216 void addSourceLine(DIE &Die, const DIGlobalVariable *G);
217 void addSourceLine(DIE &Die, const DISubprogram *SP);
218 void addSourceLine(DIE &Die, const DILabel *L);
219 void addSourceLine(DIE &Die, const DIType *Ty);
220 void addSourceLine(DIE &Die, const DIObjCProperty *Ty);
221
222 /// Add constant value entry in variable DIE.
223 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty);
224 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty);
225 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned);
226 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty);
227 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val);
228
229 /// Add constant value entry in variable DIE.
230 void addConstantFPValue(DIE &Die, const ConstantFP *CFP);
231
232 /// Add a linkage name, if it isn't empty.
233 void addLinkageName(DIE &Die, StringRef LinkageName);
234
235 /// Add template parameters in buffer.
236 void addTemplateParams(DIE &Buffer, DINodeArray TParams);
237
238 /// Add thrown types.
239 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes);
240
241 /// Add the accessibility attribute.
242 void addAccess(DIE &Die, DINode::DIFlags Flags);
243
244 /// Add a new type attribute to the specified entity.
245 ///
246 /// This takes and attribute parameter because DW_AT_friend attributes are
247 /// also type references.
248 void addType(DIE &Entity, const DIType *Ty,
249 dwarf::Attribute Attribute = dwarf::DW_AT_type);
250
251 DIE *getOrCreateNameSpace(const DINamespace *NS);
252 DIE *getOrCreateModule(const DIModule *M);
253 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false);
254
255 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
256 bool SkipSPAttributes = false);
257
258 /// Creates type DIE with specific context.
259 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty);
260
261 /// Find existing DIE or create new DIE for the given type.
262 virtual DIE *getOrCreateTypeDIE(const MDNode *TyNode);
263
264 /// Get context owner's DIE.
265 virtual DIE *getOrCreateContextDIE(const DIScope *Context);
266
267 /// Construct DIEs for types that contain vtables.
268 void constructContainingTypeDIEs();
269
270 /// Construct function argument DIEs.
271 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args);
272
273 /// Create a DIE with the given Tag, add the DIE to its parent, and
274 /// call insertDIE if MD is not null.
275 DIE &createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N = nullptr);
276
277 bool useSegmentedStringOffsetsTable() const {
278 return DD->useSegmentedStringOffsetsTable();
279 }
280
281 /// Compute the size of a header for this unit, not including the initial
282 /// length field.
283 virtual unsigned getHeaderSize() const {
284 return sizeof(int16_t) + // DWARF version number
285 Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section
286 sizeof(int8_t) + // Pointer Size (in bytes)
287 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t)
288 : 0); // DWARF v5 unit type
289 }
290
291 /// Emit the header for this unit, not including the initial length field.
292 virtual void emitHeader(bool UseOffsets) = 0;
293
294 /// Add the DW_AT_str_offsets_base attribute to the unit DIE.
295 void addStringOffsetsStart();
296
297 /// Add the DW_AT_rnglists_base attribute to the unit DIE.
298 void addRnglistsBase();
299
300 virtual DwarfCompileUnit &getCU() = 0;
301
302 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);
303
304 /// addSectionDelta - Add a label delta attribute data and value.
305 void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
306 const MCSymbol *Lo);
307
308 /// Add a Dwarf section label attribute data and value.
309 void addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
310 const MCSymbol *Label, const MCSymbol *Sec);
311
312 /// Add DW_TAG_LLVM_annotation.
313 void addAnnotation(DIE &Buffer, DINodeArray Annotations);
314
315 /// Get context owner's DIE.
316 DIE *createTypeDIE(const DICompositeType *Ty);
317
318protected:
319 ~DwarfUnit();
320
321 /// Create new static data member DIE.
322 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
323
324 /// Look up the source ID for the given file. If none currently exists,
325 /// create a new ID and insert it in the line table.
326 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0;
327
328 /// Emit the common part of the header for this unit.
329 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT);
330
331private:
332 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
333 void constructTypeDIE(DIE &Buffer, const DIStringType *BTy);
334 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
335 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy);
336 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy);
337 void constructGenericSubrangeDIE(DIE &Buffer, const DIGenericSubrange *SR,
338 DIE *IndexTy);
339 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy);
340 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy);
341 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT);
342 void constructTemplateTypeParameterDIE(DIE &Buffer,
343 const DITemplateTypeParameter *TP);
344 void constructTemplateValueParameterDIE(DIE &Buffer,
345 const DITemplateValueParameter *TVP);
346
347 /// Return the default lower bound for an array.
348 ///
349 /// If the DWARF version doesn't handle the language, return -1.
350 int64_t getDefaultLowerBound() const;
351
352 /// Get an anonymous type for index type.
353 DIE *getIndexTyDie();
354
355 /// Set D as anonymous type for index which can be reused later.
356 void setIndexTyDie(DIE *D) { IndexTyDie = D; }
357
358 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0;
359
360 /// If this is a named finished type then include it in the list of types for
361 /// the accelerator tables.
362 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,
363 const DIE &TyDIE);
364
365 virtual bool isDwoUnit() const = 0;
366 const MCSymbol *getCrossSectionRelativeBaseAddress() const override;
367
368 /// Returns 'true' if the current DwarfVersion is compatible
369 /// with the specified \p Version.
370 bool isCompatibleWithVersion(uint16_t Version) const;
371};
372
373class DwarfTypeUnit final : public DwarfUnit {
374 uint64_t TypeSignature;
375 const DIE *Ty;
376 DwarfCompileUnit &CU;
377 MCDwarfDwoLineTable *SplitLineTable;
378 bool UsedLineTable = false;
379
380 unsigned getOrCreateSourceID(const DIFile *File) override;
381 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
382 bool isDwoUnit() const override;
383
384public:
385 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW,
386 DwarfFile *DWU, unsigned UniqueID,
387 MCDwarfDwoLineTable *SplitLineTable = nullptr);
388
389 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
390 /// Returns Type Signature.
391 uint64_t getTypeSignature() const { return TypeSignature; }
392 void setType(const DIE *Ty) { this->Ty = Ty; }
393
394 /// Emit the header for this unit, not including the initial length field.
395 void emitHeader(bool UseOffsets) override;
396 unsigned getHeaderSize() const override {
397 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature
398 Asm->getDwarfOffsetByteSize(); // Type DIE Offset
399 }
400 void addGlobalName(StringRef Name, const DIE &Die,
401 const DIScope *Context) override;
402 void addGlobalTypeImpl(const DIType *Ty, const DIE &Die,
403 const DIScope *Context) override;
404 DwarfCompileUnit &getCU() override { return CU; }
405};
406} // end llvm namespace
407#endif
408