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 addGlobalType(const DIType *Ty, const DIE &Die,
132 const DIScope *Context) = 0;
133
134 /// Returns the DIE map slot for the specified debug variable.
135 ///
136 /// We delegate the request to DwarfDebug when the MDNode can be part of the
137 /// type system, since DIEs for the type system can be shared across CUs and
138 /// the mappings are kept in DwarfDebug.
139 DIE *getDIE(const DINode *D) const;
140
141 /// Returns a fresh newly allocated DIELoc.
142 DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; }
143
144 /// Insert DIE into the map.
145 ///
146 /// We delegate the request to DwarfDebug when the MDNode can be part of the
147 /// type system, since DIEs for the type system can be shared across CUs and
148 /// the mappings are kept in DwarfDebug.
149 void insertDIE(const DINode *Desc, DIE *D);
150
151 void insertDIE(DIE *D);
152
153 /// Add a flag that is true to the DIE.
154 void addFlag(DIE &Die, dwarf::Attribute Attribute);
155
156 /// Add an unsigned integer attribute data and value.
157 void addUInt(DIEValueList &Die, dwarf::Attribute Attribute,
158 std::optional<dwarf::Form> Form, uint64_t Integer);
159
160 void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer);
161
162 /// Add an signed integer attribute data and value.
163 void addSInt(DIEValueList &Die, dwarf::Attribute Attribute,
164 std::optional<dwarf::Form> Form, int64_t Integer);
165
166 void addSInt(DIELoc &Die, std::optional<dwarf::Form> Form, int64_t Integer);
167
168 /// Add a string attribute data and value.
169 ///
170 /// We always emit a reference to the string pool instead of immediate
171 /// strings so that DIEs have more predictable sizes. In the case of split
172 /// dwarf we emit an index into another table which gets us the static offset
173 /// into the string table.
174 void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
175
176 /// Add a Dwarf label attribute data and value.
177 void addLabel(DIEValueList &Die, dwarf::Attribute Attribute, dwarf::Form Form,
178 const MCSymbol *Label);
179
180 void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label);
181
182 /// Add an offset into a section attribute data and value.
183 void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer);
184
185 /// Add a dwarf op address data and value using the form given and an
186 /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
187 void addOpAddress(DIELoc &Die, const MCSymbol *Sym);
188 void addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label);
189
190 /// Add a label delta attribute data and value.
191 void addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute,
192 const MCSymbol *Hi, const MCSymbol *Lo);
193
194 /// Add a DIE attribute data and value.
195 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry);
196
197 /// Add a DIE attribute data and value.
198 void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
199
200 /// Add a type's DW_AT_signature and set the declaration flag.
201 void addDIETypeSignature(DIE &Die, uint64_t Signature);
202
203 /// Add block data.
204 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc);
205
206 /// Add block data.
207 void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block);
208 void addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form,
209 DIEBlock *Block);
210
211 /// Add location information to specified debug information entry.
212 void addSourceLine(DIE &Die, unsigned Line, const DIFile *File);
213 void addSourceLine(DIE &Die, const DILocalVariable *V);
214 void addSourceLine(DIE &Die, const DIGlobalVariable *G);
215 void addSourceLine(DIE &Die, const DISubprogram *SP);
216 void addSourceLine(DIE &Die, const DILabel *L);
217 void addSourceLine(DIE &Die, const DIType *Ty);
218 void addSourceLine(DIE &Die, const DIObjCProperty *Ty);
219
220 /// Add constant value entry in variable DIE.
221 void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty);
222 void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty);
223 void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned);
224 void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty);
225 void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val);
226
227 /// Add constant value entry in variable DIE.
228 void addConstantFPValue(DIE &Die, const ConstantFP *CFP);
229
230 /// Add a linkage name, if it isn't empty.
231 void addLinkageName(DIE &Die, StringRef LinkageName);
232
233 /// Add template parameters in buffer.
234 void addTemplateParams(DIE &Buffer, DINodeArray TParams);
235
236 /// Add thrown types.
237 void addThrownTypes(DIE &Die, DINodeArray ThrownTypes);
238
239 /// Add the accessibility attribute.
240 void addAccess(DIE &Die, DINode::DIFlags Flags);
241
242 /// Add a new type attribute to the specified entity.
243 ///
244 /// This takes and attribute parameter because DW_AT_friend attributes are
245 /// also type references.
246 void addType(DIE &Entity, const DIType *Ty,
247 dwarf::Attribute Attribute = dwarf::DW_AT_type);
248
249 DIE *getOrCreateNameSpace(const DINamespace *NS);
250 DIE *getOrCreateModule(const DIModule *M);
251 DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false);
252
253 void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
254 bool SkipSPAttributes = false);
255
256 /// Creates type DIE with specific context.
257 DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty);
258
259 /// Find existing DIE or create new DIE for the given type.
260 virtual DIE *getOrCreateTypeDIE(const MDNode *TyNode);
261
262 /// Get context owner's DIE.
263 virtual DIE *getOrCreateContextDIE(const DIScope *Context);
264
265 /// Construct DIEs for types that contain vtables.
266 void constructContainingTypeDIEs();
267
268 /// Construct function argument DIEs.
269 void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args);
270
271 /// Create a DIE with the given Tag, add the DIE to its parent, and
272 /// call insertDIE if MD is not null.
273 DIE &createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N = nullptr);
274
275 bool useSegmentedStringOffsetsTable() const {
276 return DD->useSegmentedStringOffsetsTable();
277 }
278
279 /// Compute the size of a header for this unit, not including the initial
280 /// length field.
281 virtual unsigned getHeaderSize() const {
282 return sizeof(int16_t) + // DWARF version number
283 Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section
284 sizeof(int8_t) + // Pointer Size (in bytes)
285 (DD->getDwarfVersion() >= 5 ? sizeof(int8_t)
286 : 0); // DWARF v5 unit type
287 }
288
289 /// Emit the header for this unit, not including the initial length field.
290 virtual void emitHeader(bool UseOffsets) = 0;
291
292 /// Add the DW_AT_str_offsets_base attribute to the unit DIE.
293 void addStringOffsetsStart();
294
295 /// Add the DW_AT_rnglists_base attribute to the unit DIE.
296 void addRnglistsBase();
297
298 virtual DwarfCompileUnit &getCU() = 0;
299
300 void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);
301
302 /// addSectionDelta - Add a label delta attribute data and value.
303 void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
304 const MCSymbol *Lo);
305
306 /// Add a Dwarf section label attribute data and value.
307 void addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
308 const MCSymbol *Label, const MCSymbol *Sec);
309
310 /// Add DW_TAG_LLVM_annotation.
311 void addAnnotation(DIE &Buffer, DINodeArray Annotations);
312
313 /// Get context owner's DIE.
314 DIE *createTypeDIE(const DICompositeType *Ty);
315
316protected:
317 ~DwarfUnit();
318
319 /// Create new static data member DIE.
320 DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
321
322 /// Look up the source ID for the given file. If none currently exists,
323 /// create a new ID and insert it in the line table.
324 virtual unsigned getOrCreateSourceID(const DIFile *File) = 0;
325
326 /// Emit the common part of the header for this unit.
327 void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT);
328
329private:
330 void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
331 void constructTypeDIE(DIE &Buffer, const DIStringType *BTy);
332 void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
333 void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy);
334 void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy);
335 void constructGenericSubrangeDIE(DIE &Buffer, const DIGenericSubrange *SR,
336 DIE *IndexTy);
337 void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy);
338 void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy);
339 DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT);
340 void constructTemplateTypeParameterDIE(DIE &Buffer,
341 const DITemplateTypeParameter *TP);
342 void constructTemplateValueParameterDIE(DIE &Buffer,
343 const DITemplateValueParameter *TVP);
344
345 /// Return the default lower bound for an array.
346 ///
347 /// If the DWARF version doesn't handle the language, return -1.
348 int64_t getDefaultLowerBound() const;
349
350 /// Get an anonymous type for index type.
351 DIE *getIndexTyDie();
352
353 /// Set D as anonymous type for index which can be reused later.
354 void setIndexTyDie(DIE *D) { IndexTyDie = D; }
355
356 virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0;
357
358 /// If this is a named finished type then include it in the list of types for
359 /// the accelerator tables.
360 void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,
361 const DIE &TyDIE);
362
363 virtual bool isDwoUnit() const = 0;
364 const MCSymbol *getCrossSectionRelativeBaseAddress() const override;
365
366 /// Returns 'true' if the current DwarfVersion is compatible
367 /// with the specified \p Version.
368 bool isCompatibleWithVersion(uint16_t Version) const;
369};
370
371class DwarfTypeUnit final : public DwarfUnit {
372 uint64_t TypeSignature;
373 const DIE *Ty;
374 DwarfCompileUnit &CU;
375 MCDwarfDwoLineTable *SplitLineTable;
376 bool UsedLineTable = false;
377
378 unsigned getOrCreateSourceID(const DIFile *File) override;
379 void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
380 bool isDwoUnit() const override;
381
382public:
383 DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW,
384 DwarfFile *DWU, unsigned UniqueID,
385 MCDwarfDwoLineTable *SplitLineTable = nullptr);
386
387 void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
388 /// Returns Type Signature.
389 uint64_t getTypeSignature() const { return TypeSignature; }
390 void setType(const DIE *Ty) { this->Ty = Ty; }
391
392 /// Emit the header for this unit, not including the initial length field.
393 void emitHeader(bool UseOffsets) override;
394 unsigned getHeaderSize() const override {
395 return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature
396 Asm->getDwarfOffsetByteSize(); // Type DIE Offset
397 }
398 void addGlobalName(StringRef Name, const DIE &Die,
399 const DIScope *Context) override;
400 void addGlobalType(const DIType *Ty, const DIE &Die,
401 const DIScope *Context) override;
402 DwarfCompileUnit &getCU() override { return CU; }
403};
404} // end llvm namespace
405#endif
406

source code of llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h