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