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/ADT/Optional.h"
19#include "llvm/ADT/StringMap.h"
20#include "llvm/CodeGen/AsmPrinter.h"
21#include "llvm/CodeGen/DIE.h"
22#include "llvm/IR/DIBuilder.h"
23#include "llvm/IR/DebugInfo.h"
24#include "llvm/MC/MCDwarf.h"
25#include "llvm/MC/MCExpr.h"
26#include "llvm/MC/MCSection.h"
27
28namespace llvm {
29
30class MachineOperand;
31class ConstantInt;
32class ConstantFP;
33class DbgVariable;
34class DwarfCompileUnit;
35
36//===----------------------------------------------------------------------===//
37/// This dwarf writer support class manages information associated with a
38/// source file.
39class DwarfUnit : public DIEUnit {
40protected:
41  /// MDNode for the compile unit.
42  const DICompileUnit *CUNode;
43
44  // All DIEValues are allocated through this allocator.
45  BumpPtrAllocator DIEValueAllocator;
46
47  /// Target of Dwarf emission.
48  AsmPrinter *Asm;
49
50  /// Emitted at the end of the CU and used to compute the CU Length field.
51  MCSymbol *EndLabel = nullptr;
52
53  // Holders for some common dwarf information.
54  DwarfDebug *DD;
55  DwarfFile *DU;
56
57  /// An anonymous type for index type.  Owned by DIEUnit.
58  DIE *IndexTyDie;
59
60  /// Tracks the mapping of unit level debug information variables to debug
61  /// information entries.
62  DenseMap<const MDNode *, DIE *> MDNodeToDieMap;
63
64  /// A list of all the DIEBlocks in use.
65  std::vector<DIEBlock *> DIEBlocks;
66
67  /// A list of all the DIELocs in use.
68  std::vector<DIELoc *> DIELocs;
69
70  /// This map is used to keep track of subprogram DIEs that need
71  /// DW_AT_containing_type attribute. This attribute points to a DIE that
72  /// corresponds to the MDNode mapped with the subprogram DIE.
73  DenseMap<DIE *, const DINode *> ContainingTypeMap;
74
75  DwarfUnit(dwarf::Tag, const DICompileUnit *Node, AsmPrinter *A, DwarfDebug *DW,
76            DwarfFile *DWU);
77
78  bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie);
79
80  bool shareAcrossDWOCUs() const;
81  bool isShareableAcrossCUs(const DINode *D) const;
82
83public:
84  // Accessors.
85  AsmPrinter* getAsmPrinter() const { return Asm; }
86  MCSymbol *getEndLabel() const { return EndLabel; }
87  uint16_t getLanguage() const { return CUNode->getSourceLanguage(); }
88  const DICompileUnit *getCUNode() const { return CUNode; }
89
90  uint16_t getDwarfVersion() const { return DD->getDwarfVersion(); }
91
92  /// Return true if this compile unit has something to write out.
93  bool hasContent() const { return getUnitDie().hasChildren(); }
94
95  /// Get string containing language specific context for a global name.
96  ///
97  /// Walks the metadata parent chain in a language specific manner (using the
98  /// compile unit language) and returns it as a string. This is done at the
99  /// metadata level because DIEs may not currently have been added to the
100  /// parent context and walking the DIEs looking for names is more expensive
101  /// than walking the metadata.
102  std::string getParentContextString(const DIScope *Context) const;
103
104  /// Add a new global name to the compile unit.
105  virtual void addGlobalName(StringRef Name, const DIE &Die,
106                             const DIScope *Context) = 0;
107
108  /// Add a new global type to the compile unit.
109  virtual void addGlobalType(const DIType *Ty, const DIE &Die,
110                             const DIScope *Context) = 0;
111
112  /// Returns the DIE map slot for the specified debug variable.
113  ///
114  /// We delegate the request to DwarfDebug when the MDNode can be part of the
115  /// type system, since DIEs for the type system can be shared across CUs and
116  /// the mappings are kept in DwarfDebug.
117  DIE *getDIE(const DINode *D) const;
118
119  /// Returns a fresh newly allocated DIELoc.
120  DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; }
121
122  /// Insert DIE into the map.
123  ///
124  /// We delegate the request to DwarfDebug when the MDNode can be part of the
125  /// type system, since DIEs for the type system can be shared across CUs and
126  /// the mappings are kept in DwarfDebug.
127  void insertDIE(const DINode *Desc, DIE *D);
128
129  void insertDIE(DIE *D);
130
131  /// Add a flag that is true to the DIE.
132  void addFlag(DIE &Die, dwarf::Attribute Attribute);
133
134  /// Add an unsigned integer attribute data and value.
135  void addUInt(DIEValueList &Die, dwarf::Attribute Attribute,
136               Optional<dwarf::Form> Form, uint64_t Integer);
137
138  void addUInt(DIEValueList &Block, dwarf::Form Form, uint64_t Integer);
139
140  /// Add an signed integer attribute data and value.
141  void addSInt(DIEValueList &Die, dwarf::Attribute Attribute,
142               Optional<dwarf::Form> Form, int64_t Integer);
143
144  void addSInt(DIELoc &Die, Optional<dwarf::Form> Form, int64_t Integer);
145
146  /// Add a string attribute data and value.
147  ///
148  /// We always emit a reference to the string pool instead of immediate
149  /// strings so that DIEs have more predictable sizes. In the case of split
150  /// dwarf we emit an index into another table which gets us the static offset
151  /// into the string table.
152  void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
153
154  /// Add a Dwarf label attribute data and value.
155  DIEValueList::value_iterator addLabel(DIEValueList &Die,
156                                        dwarf::Attribute Attribute,
157                                        dwarf::Form Form,
158                                        const MCSymbol *Label);
159
160  void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label);
161
162  /// Add an offset into a section attribute data and value.
163  void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer);
164
165  /// Add a dwarf op address data and value using the form given and an
166  /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
167  void addOpAddress(DIELoc &Die, const MCSymbol *Sym);
168
169  /// Add a label delta attribute data and value.
170  void addLabelDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
171                     const MCSymbol *Lo);
172
173  /// Add a DIE attribute data and value.
174  void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry);
175
176  /// Add a DIE attribute data and value.
177  void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
178
179  /// Add a type's DW_AT_signature and set the  declaration flag.
180  void addDIETypeSignature(DIE &Die, uint64_t Signature);
181
182  /// Add block data.
183  void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc);
184
185  /// Add block data.
186  void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block);
187
188  /// Add location information to specified debug information entry.
189  void addSourceLine(DIE &Die, unsigned Line, const DIFile *File);
190  void addSourceLine(DIE &Die, const DILocalVariable *V);
191  void addSourceLine(DIE &Die, const DIGlobalVariable *G);
192  void addSourceLine(DIE &Die, const DISubprogram *SP);
193  void addSourceLine(DIE &Die, const DILabel *L);
194  void addSourceLine(DIE &Die, const DIType *Ty);
195  void addSourceLine(DIE &Die, const DIObjCProperty *Ty);
196
197  /// Add constant value entry in variable DIE.
198  void addConstantValue(DIE &Die, const MachineOperand &MO, const DIType *Ty);
199  void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty);
200  void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty);
201  void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned);
202  void addConstantValue(DIE &Die, uint64_t Val, const DIType *Ty);
203  void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val);
204
205  /// Add constant value entry in variable DIE.
206  void addConstantFPValue(DIE &Die, const MachineOperand &MO);
207  void addConstantFPValue(DIE &Die, const ConstantFP *CFP);
208
209  /// Add a linkage name, if it isn't empty.
210  void addLinkageName(DIE &Die, StringRef LinkageName);
211
212  /// Add template parameters in buffer.
213  void addTemplateParams(DIE &Buffer, DINodeArray TParams);
214
215  /// Add thrown types.
216  void addThrownTypes(DIE &Die, DINodeArray ThrownTypes);
217
218  /// Add a new type attribute to the specified entity.
219  ///
220  /// This takes and attribute parameter because DW_AT_friend attributes are
221  /// also type references.
222  void addType(DIE &Entity, const DIType *Ty,
223               dwarf::Attribute Attribute = dwarf::DW_AT_type);
224
225  DIE *getOrCreateNameSpace(const DINamespace *NS);
226  DIE *getOrCreateModule(const DIModule *M);
227  DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false);
228
229  void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
230                                 bool SkipSPAttributes = false);
231
232  /// Creates type DIE with specific context.
233  DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty);
234
235  /// Find existing DIE or create new DIE for the given type.
236  DIE *getOrCreateTypeDIE(const MDNode *TyNode);
237
238  /// Get context owner's DIE.
239  DIE *getOrCreateContextDIE(const DIScope *Context);
240
241  /// Construct DIEs for types that contain vtables.
242  void constructContainingTypeDIEs();
243
244  /// Construct function argument DIEs.
245  void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args);
246
247  /// Create a DIE with the given Tag, add the DIE to its parent, and
248  /// call insertDIE if MD is not null.
249  DIE &createAndAddDIE(unsigned Tag, DIE &Parent, const DINode *N = nullptr);
250
251  bool useSegmentedStringOffsetsTable() const {
252    return DD->useSegmentedStringOffsetsTable();
253  }
254
255  /// Compute the size of a header for this unit, not including the initial
256  /// length field.
257  virtual unsigned getHeaderSize() const {
258    return sizeof(int16_t) + // DWARF version number
259           sizeof(int32_t) + // Offset Into Abbrev. Section
260           sizeof(int8_t) +  // Pointer Size (in bytes)
261           (DD->getDwarfVersion() >= 5 ? sizeof(int8_t)
262                                       : 0); // DWARF v5 unit type
263  }
264
265  /// Emit the header for this unit, not including the initial length field.
266  virtual void emitHeader(bool UseOffsets) = 0;
267
268  /// Add the DW_AT_str_offsets_base attribute to the unit DIE.
269  void addStringOffsetsStart();
270
271  /// Add the DW_AT_rnglists_base attribute to the unit DIE.
272  void addRnglistsBase();
273
274  virtual DwarfCompileUnit &getCU() = 0;
275
276  void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);
277
278  /// addSectionDelta - Add a label delta attribute data and value.
279  DIE::value_iterator addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
280                                      const MCSymbol *Hi, const MCSymbol *Lo);
281
282  /// Add a Dwarf section label attribute data and value.
283  DIE::value_iterator addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
284                                      const MCSymbol *Label,
285                                      const MCSymbol *Sec);
286
287  /// If the \p File has an MD5 checksum, return it as an MD5Result
288  /// allocated in the MCContext.
289  Optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
290
291  /// Get context owner's DIE.
292  DIE *createTypeDIE(const DICompositeType *Ty);
293
294protected:
295  ~DwarfUnit();
296
297  /// Create new static data member DIE.
298  DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
299
300  /// Look up the source ID for the given file. If none currently exists,
301  /// create a new ID and insert it in the line table.
302  virtual unsigned getOrCreateSourceID(const DIFile *File) = 0;
303
304  /// Emit the common part of the header for this unit.
305  void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT);
306
307private:
308  void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
309  void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
310  void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy);
311  void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy);
312  void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy);
313  void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy);
314  DIE &constructMemberDIE(DIE &Buffer, const DIDerivedType *DT);
315  void constructTemplateTypeParameterDIE(DIE &Buffer,
316                                         const DITemplateTypeParameter *TP);
317  void constructTemplateValueParameterDIE(DIE &Buffer,
318                                          const DITemplateValueParameter *TVP);
319
320  /// Return the default lower bound for an array.
321  ///
322  /// If the DWARF version doesn't handle the language, return -1.
323  int64_t getDefaultLowerBound() const;
324
325  /// Get an anonymous type for index type.
326  DIE *getIndexTyDie();
327
328  /// Set D as anonymous type for index which can be reused later.
329  void setIndexTyDie(DIE *D) { IndexTyDie = D; }
330
331  virtual void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) = 0;
332
333  /// If this is a named finished type then include it in the list of types for
334  /// the accelerator tables.
335  void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,
336                               const DIE &TyDIE);
337
338  virtual bool isDwoUnit() const = 0;
339  const MCSymbol *getCrossSectionRelativeBaseAddress() const override;
340};
341
342class DwarfTypeUnit final : public DwarfUnit {
343  uint64_t TypeSignature;
344  const DIE *Ty;
345  DwarfCompileUnit &CU;
346  MCDwarfDwoLineTable *SplitLineTable;
347  bool UsedLineTable = false;
348
349  unsigned getOrCreateSourceID(const DIFile *File) override;
350  void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
351  bool isDwoUnit() const override;
352
353public:
354  DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW,
355                DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr);
356
357  void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
358  void setType(const DIE *Ty) { this->Ty = Ty; }
359
360  /// Emit the header for this unit, not including the initial length field.
361  void emitHeader(bool UseOffsets) override;
362  unsigned getHeaderSize() const override {
363    return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature
364           sizeof(uint32_t);                               // Type DIE Offset
365  }
366  void addGlobalName(StringRef Name, const DIE &Die,
367                     const DIScope *Context) override;
368  void addGlobalType(const DIType *Ty, const DIE &Die,
369                     const DIScope *Context) override;
370  DwarfCompileUnit &getCU() override { return CU; }
371};
372} // end llvm namespace
373#endif
374