1 //===- llvm/CodeGen/DwarfCompileUnit.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_DWARFCOMPILEUNIT_H
14 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H
15 
16 #include "DwarfDebug.h"
17 #include "DwarfUnit.h"
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringMap.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/BinaryFormat/Dwarf.h"
24 #include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
25 #include "llvm/CodeGen/DIE.h"
26 #include "llvm/CodeGen/LexicalScopes.h"
27 #include "llvm/IR/DebugInfoMetadata.h"
28 #include "llvm/Support/Casting.h"
29 #include <algorithm>
30 #include <cassert>
31 #include <cstdint>
32 #include <memory>
33 
34 namespace llvm {
35 
36 class AsmPrinter;
37 class DwarfFile;
38 class GlobalVariable;
39 class MCExpr;
40 class MCSymbol;
41 class MDNode;
42 
43 class DwarfCompileUnit final : public DwarfUnit {
44   /// A numeric ID unique among all CUs in the module
45   unsigned UniqueID;
46   bool HasRangeLists = false;
47 
48   /// The attribute index of DW_AT_stmt_list in the compile unit DIE, avoiding
49   /// the need to search for it in applyStmtList.
50   DIE::value_iterator StmtListValue;
51 
52   /// Skeleton unit associated with this unit.
53   DwarfCompileUnit *Skeleton = nullptr;
54 
55   /// The start of the unit within its section.
56   MCSymbol *LabelBegin;
57 
58   /// The start of the unit macro info within macro section.
59   MCSymbol *MacroLabelBegin;
60 
61   using ImportedEntityList = SmallVector<const MDNode *, 8>;
62   using ImportedEntityMap = DenseMap<const MDNode *, ImportedEntityList>;
63 
64   ImportedEntityMap ImportedEntities;
65 
66   /// GlobalNames - A map of globally visible named entities for this unit.
67   StringMap<const DIE *> GlobalNames;
68 
69   /// GlobalTypes - A map of globally visible types for this unit.
70   StringMap<const DIE *> GlobalTypes;
71 
72   // List of ranges for a given compile unit.
73   SmallVector<RangeSpan, 2> CURanges;
74 
75   // The base address of this unit, if any. Used for relative references in
76   // ranges/locs.
77   const MCSymbol *BaseAddress = nullptr;
78 
79   DenseMap<const MDNode *, DIE *> AbstractSPDies;
80   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
81 
82   /// DWO ID for correlating skeleton and split units.
83   uint64_t DWOId = 0;
84 
85   /// Construct a DIE for the given DbgVariable without initializing the
86   /// DbgVariable's DIE reference.
87   DIE *constructVariableDIEImpl(const DbgVariable &DV, bool Abstract);
88 
89   bool isDwoUnit() const override;
90 
91   DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
92     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
93       return AbstractSPDies;
94     return DU->getAbstractSPDies();
95   }
96 
97   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
98     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
99       return AbstractEntities;
100     return DU->getAbstractEntities();
101   }
102 
103 public:
104   DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
105                    DwarfDebug *DW, DwarfFile *DWU);
106 
107   bool hasRangeLists() const { return HasRangeLists; }
108   unsigned getUniqueID() const { return UniqueID; }
109 
110   DwarfCompileUnit *getSkeleton() const {
111     return Skeleton;
112   }
113 
114   bool includeMinimalInlineScopes() const;
115 
116   void initStmtList();
117 
118   /// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
119   void applyStmtList(DIE &D);
120 
121   /// A pair of GlobalVariable and DIExpression.
122   struct GlobalExpr {
123     const GlobalVariable *Var;
124     const DIExpression *Expr;
125   };
126 
127   struct BaseTypeRef {
128     BaseTypeRef(unsigned BitSize, dwarf::TypeKind Encoding) :
129       BitSize(BitSize), Encoding(Encoding) {}
130     unsigned BitSize;
131     dwarf::TypeKind Encoding;
132     DIE *Die = nullptr;
133   };
134 
135   std::vector<BaseTypeRef> ExprRefedBaseTypes;
136 
137   /// Get or create global variable DIE.
138   DIE *
139   getOrCreateGlobalVariableDIE(const DIGlobalVariable *GV,
140                                ArrayRef<GlobalExpr> GlobalExprs);
141 
142   DIE *getOrCreateCommonBlock(const DICommonBlock *CB,
143                               ArrayRef<GlobalExpr> GlobalExprs);
144 
145   void addLocationAttribute(DIE *ToDIE, const DIGlobalVariable *GV,
146                             ArrayRef<GlobalExpr> GlobalExprs);
147 
148   /// addLabelAddress - Add a dwarf label attribute data and value using
149   /// either DW_FORM_addr or DW_FORM_GNU_addr_index.
150   void addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
151                        const MCSymbol *Label);
152 
153   /// addLocalLabelAddress - Add a dwarf label attribute data and value using
154   /// DW_FORM_addr only.
155   void addLocalLabelAddress(DIE &Die, dwarf::Attribute Attribute,
156                             const MCSymbol *Label);
157 
158   DwarfCompileUnit &getCU() override { return *this; }
159 
160   unsigned getOrCreateSourceID(const DIFile *File) override;
161 
162   void addImportedEntity(const DIImportedEntity* IE) {
163     DIScope *Scope = IE->getScope();
164     assert(Scope && "Invalid Scope encoding!");
165     if (!isa<DILocalScope>(Scope))
166       // No need to add imported enities that are not local declaration.
167       return;
168 
169     auto *LocalScope = cast<DILocalScope>(Scope)->getNonLexicalBlockFileScope();
170     ImportedEntities[LocalScope].push_back(IE);
171   }
172 
173   /// addRange - Add an address range to the list of ranges for this unit.
174   void addRange(RangeSpan Range);
175 
176   void attachLowHighPC(DIE &D, const MCSymbol *Begin, const MCSymbol *End);
177 
178   /// Find DIE for the given subprogram and attach appropriate
179   /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
180   /// variables in this scope then create and insert DIEs for these
181   /// variables.
182   DIE &updateSubprogramScopeDIE(const DISubprogram *SP);
183 
184   void constructScopeDIE(LexicalScope *Scope,
185                          SmallVectorImpl<DIE *> &FinalChildren);
186 
187   /// A helper function to construct a RangeSpanList for a given
188   /// lexical scope.
189   void addScopeRangeList(DIE &ScopeDIE, SmallVector<RangeSpan, 2> Range);
190 
191   void attachRangesOrLowHighPC(DIE &D, SmallVector<RangeSpan, 2> Ranges);
192 
193   void attachRangesOrLowHighPC(DIE &D,
194                                const SmallVectorImpl<InsnRange> &Ranges);
195 
196   /// This scope represents inlined body of a function. Construct
197   /// DIE to represent this concrete inlined copy of the function.
198   DIE *constructInlinedScopeDIE(LexicalScope *Scope);
199 
200   /// Construct new DW_TAG_lexical_block for this scope and
201   /// attach DW_AT_low_pc/DW_AT_high_pc labels.
202   DIE *constructLexicalScopeDIE(LexicalScope *Scope);
203 
204   /// constructVariableDIE - Construct a DIE for the given DbgVariable.
205   DIE *constructVariableDIE(DbgVariable &DV, bool Abstract = false);
206 
207   DIE *constructVariableDIE(DbgVariable &DV, const LexicalScope &Scope,
208                             DIE *&ObjectPointer);
209 
210   /// Construct a DIE for the given DbgLabel.
211   DIE *constructLabelDIE(DbgLabel &DL, const LexicalScope &Scope);
212 
213   /// A helper function to create children of a Scope DIE.
214   DIE *createScopeChildrenDIE(LexicalScope *Scope,
215                               SmallVectorImpl<DIE *> &Children,
216                               bool *HasNonScopeChildren = nullptr);
217 
218   void createBaseTypeDIEs();
219 
220   /// Construct a DIE for this subprogram scope.
221   DIE &constructSubprogramScopeDIE(const DISubprogram *Sub,
222                                    LexicalScope *Scope);
223 
224   DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
225 
226   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
227 
228   /// Construct a call site entry DIE describing a call within \p Scope to a
229   /// callee described by \p CalleeSP. \p IsTail specifies whether the call is
230   /// a tail call. \p PCOffset must be non-zero for non-tail calls or be the
231   /// function-local offset to PC value after the call instruction.
232   DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram &CalleeSP,
233                                  bool IsTail, const MCExpr *PCOffset);
234 
235   /// Construct import_module DIE.
236   DIE *constructImportedEntityDIE(const DIImportedEntity *Module);
237 
238   void finishSubprogramDefinition(const DISubprogram *SP);
239   void finishEntityDefinition(const DbgEntity *Entity);
240 
241   /// Find abstract variable associated with Var.
242   using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
243   DbgEntity *getExistingAbstractEntity(const DINode *Node);
244   void createAbstractEntity(const DINode *Node, LexicalScope *Scope);
245 
246   /// Set the skeleton unit associated with this unit.
247   void setSkeleton(DwarfCompileUnit &Skel) { Skeleton = &Skel; }
248 
249   unsigned getHeaderSize() const override {
250     // DWARF v5 added the DWO ID to the header for split/skeleton units.
251     unsigned DWOIdSize =
252         DD->getDwarfVersion() >= 5 && DD->useSplitDwarf() ? sizeof(uint64_t)
253                                                           : 0;
254     return DwarfUnit::getHeaderSize() + DWOIdSize;
255   }
256   unsigned getLength() {
257     return sizeof(uint32_t) + // Length field
258         getHeaderSize() + getUnitDie().getSize();
259   }
260 
261   void emitHeader(bool UseOffsets) override;
262 
263   /// Add the DW_AT_addr_base attribute to the unit DIE.
264   void addAddrTableBase();
265 
266   MCSymbol *getLabelBegin() const {
267     assert(getSection());
268     return LabelBegin;
269   }
270 
271   MCSymbol *getMacroLabelBegin() const {
272     return MacroLabelBegin;
273   }
274 
275   /// Add a new global name to the compile unit.
276   void addGlobalName(StringRef Name, const DIE &Die,
277                      const DIScope *Context) override;
278 
279   /// Add a new global name present in a type unit to this compile unit.
280   void addGlobalNameForTypeUnit(StringRef Name, const DIScope *Context);
281 
282   /// Add a new global type to the compile unit.
283   void addGlobalType(const DIType *Ty, const DIE &Die,
284                      const DIScope *Context) override;
285 
286   /// Add a new global type present in a type unit to this compile unit.
287   void addGlobalTypeUnitType(const DIType *Ty, const DIScope *Context);
288 
289   const StringMap<const DIE *> &getGlobalNames() const { return GlobalNames; }
290   const StringMap<const DIE *> &getGlobalTypes() const { return GlobalTypes; }
291 
292   /// Add DW_AT_location attribute for a DbgVariable based on provided
293   /// MachineLocation.
294   void addVariableAddress(const DbgVariable &DV, DIE &Die,
295                           MachineLocation Location);
296   /// Add an address attribute to a die based on the location provided.
297   void addAddress(DIE &Die, dwarf::Attribute Attribute,
298                   const MachineLocation &Location);
299 
300   /// Start with the address based on the location provided, and generate the
301   /// DWARF information necessary to find the actual variable (navigating the
302   /// extra location information encoded in the type) based on the starting
303   /// location.  Add the DWARF information to the die.
304   void addComplexAddress(const DbgVariable &DV, DIE &Die,
305                          dwarf::Attribute Attribute,
306                          const MachineLocation &Location);
307 
308   /// Add a Dwarf loclistptr attribute data and value.
309   void addLocationList(DIE &Die, dwarf::Attribute Attribute, unsigned Index);
310   void applyVariableAttributes(const DbgVariable &Var, DIE &VariableDie);
311 
312   /// Add a Dwarf expression attribute data and value.
313   void addExpr(DIELoc &Die, dwarf::Form Form, const MCExpr *Expr);
314 
315   /// Add an attribute containing an address expression to \p Die.
316   void addAddressExpr(DIE &Die, dwarf::Attribute Attribute, const MCExpr *Expr);
317 
318   void applySubprogramAttributesToDefinition(const DISubprogram *SP,
319                                              DIE &SPDie);
320 
321   void applyLabelAttributes(const DbgLabel &Label, DIE &LabelDie);
322 
323   /// getRanges - Get the list of ranges for this unit.
324   const SmallVectorImpl<RangeSpan> &getRanges() const { return CURanges; }
325   SmallVector<RangeSpan, 2> takeRanges() { return std::move(CURanges); }
326 
327   void setBaseAddress(const MCSymbol *Base) { BaseAddress = Base; }
328   const MCSymbol *getBaseAddress() const { return BaseAddress; }
329 
330   uint64_t getDWOId() const { return DWOId; }
331   void setDWOId(uint64_t DwoId) { DWOId = DwoId; }
332 
333   bool hasDwarfPubSections() const;
334 
335   void addBaseTypeRef(DIEValueList &Die, int64_t Idx);
336 };
337 
338 } // end namespace llvm
339 
340 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H
341