1 //===- llvm/CodeGen/DwarfFile.h - Dwarf Debug Framework ---------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFFILE_H
11 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFFILE_H
12 
13 #include "DwarfStringPool.h"
14 #include "llvm/ADT/DenseMap.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/CodeGen/DIE.h"
18 #include "llvm/IR/Metadata.h"
19 #include "llvm/Support/Allocator.h"
20 #include <map>
21 #include <memory>
22 #include <utility>
23 
24 namespace llvm {
25 
26 class AsmPrinter;
27 class DbgEntity;
28 class DbgVariable;
29 class DbgLabel;
30 class DwarfCompileUnit;
31 class DwarfUnit;
32 class LexicalScope;
33 class MCSection;
34 
35 // Data structure to hold a range for range lists.
36 class RangeSpan {
37 public:
38   RangeSpan(MCSymbol *S, MCSymbol *E) : Start(S), End(E) {}
39   const MCSymbol *getStart() const { return Start; }
40   const MCSymbol *getEnd() const { return End; }
41   void setEnd(const MCSymbol *E) { End = E; }
42 
43 private:
44   const MCSymbol *Start, *End;
45 };
46 
47 class RangeSpanList {
48 private:
49   // Index for locating within the debug_range section this particular span.
50   MCSymbol *RangeSym;
51   const MCSymbol **CUBaseAddress;
52   // List of ranges.
53   SmallVector<RangeSpan, 2> Ranges;
54 
55 public:
56   RangeSpanList(MCSymbol *Sym, const MCSymbol *&CUBaseAddress,
57                 SmallVector<RangeSpan, 2> Ranges)
58       : RangeSym(Sym), CUBaseAddress(&CUBaseAddress),
59         Ranges(std::move(Ranges)) {}
60   MCSymbol *getSym() const { return RangeSym; }
61   const MCSymbol *&getBaseAddress() const { return *CUBaseAddress; }
62   const SmallVectorImpl<RangeSpan> &getRanges() const { return Ranges; }
63   void addRange(RangeSpan Range) { Ranges.push_back(Range); }
64 };
65 
66 class DwarfFile {
67   // Target of Dwarf emission, used for sizing of abbreviations.
68   AsmPrinter *Asm;
69 
70   BumpPtrAllocator AbbrevAllocator;
71 
72   // Used to uniquely define abbreviations.
73   DIEAbbrevSet Abbrevs;
74 
75   // A pointer to all units in the section.
76   SmallVector<std::unique_ptr<DwarfCompileUnit>, 1> CUs;
77 
78   DwarfStringPool StrPool;
79 
80   // List of range lists for a given compile unit, separate from the ranges for
81   // the CU itself.
82   SmallVector<RangeSpanList, 1> CURangeLists;
83 
84   /// DWARF v5: The symbol that designates the start of the contribution to
85   /// the string offsets table. The contribution is shared by all units.
86   MCSymbol *StringOffsetsStartSym = nullptr;
87 
88   /// DWARF v5: The symbol that designates the base of the range list table.
89   /// The table is shared by all units.
90   MCSymbol *RnglistsTableBaseSym = nullptr;
91 
92   /// DWARF v5: The symbol that designates the base of the locations list table.
93   /// The table is shared by all units.
94   MCSymbol *LoclistsTableBaseSym = nullptr;
95 
96   /// The variables of a lexical scope.
97   struct ScopeVars {
98     /// We need to sort Args by ArgNo and check for duplicates. This could also
99     /// be implemented as a list or vector + std::lower_bound().
100     std::map<unsigned, DbgVariable *> Args;
101     SmallVector<DbgVariable *, 8> Locals;
102   };
103   /// Collection of DbgVariables of each lexical scope.
104   DenseMap<LexicalScope *, ScopeVars> ScopeVariables;
105 
106   /// Collection of DbgLabels of each lexical scope.
107   using LabelList = SmallVector<DbgLabel *, 4>;
108   DenseMap<LexicalScope *, LabelList> ScopeLabels;
109 
110   // Collection of abstract subprogram DIEs.
111   DenseMap<const MDNode *, DIE *> AbstractSPDies;
112   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
113 
114   /// Maps MDNodes for type system with the corresponding DIEs. These DIEs can
115   /// be shared across CUs, that is why we keep the map here instead
116   /// of in DwarfCompileUnit.
117   DenseMap<const MDNode *, DIE *> DITypeNodeToDieMap;
118 
119 public:
120   DwarfFile(AsmPrinter *AP, StringRef Pref, BumpPtrAllocator &DA);
121 
122   const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
123     return CUs;
124   }
125 
126   std::pair<uint32_t, RangeSpanList *> addRange(const MCSymbol *&CUBaseAddress,
127                                                 SmallVector<RangeSpan, 2> R);
128 
129   /// getRangeLists - Get the vector of range lists.
130   const SmallVectorImpl<RangeSpanList> &getRangeLists() const {
131     return CURangeLists;
132   }
133 
134   /// Compute the size and offset of a DIE given an incoming Offset.
135   unsigned computeSizeAndOffset(DIE &Die, unsigned Offset);
136 
137   /// Compute the size and offset of all the DIEs.
138   void computeSizeAndOffsets();
139 
140   /// Compute the size and offset of all the DIEs in the given unit.
141   /// \returns The size of the root DIE.
142   unsigned computeSizeAndOffsetsForUnit(DwarfUnit *TheU);
143 
144   /// Add a unit to the list of CUs.
145   void addUnit(std::unique_ptr<DwarfCompileUnit> U);
146 
147   /// Emit all of the units to the section listed with the given
148   /// abbreviation section.
149   void emitUnits(bool UseOffsets);
150 
151   /// Emit the given unit to its section.
152   void emitUnit(DwarfUnit *U, bool UseOffsets);
153 
154   /// Emit a set of abbreviations to the specific section.
155   void emitAbbrevs(MCSection *);
156 
157   /// Emit all of the strings to the section given. If OffsetSection is
158   /// non-null, emit a table of string offsets to it. If UseRelativeOffsets
159   /// is false, emit absolute offsets to the strings. Otherwise, emit
160   /// relocatable references to the strings if they are supported by the target.
161   void emitStrings(MCSection *StrSection, MCSection *OffsetSection = nullptr,
162                    bool UseRelativeOffsets = false);
163 
164   /// Returns the string pool.
165   DwarfStringPool &getStringPool() { return StrPool; }
166 
167   MCSymbol *getStringOffsetsStartSym() const { return StringOffsetsStartSym; }
168   void setStringOffsetsStartSym(MCSymbol *Sym) { StringOffsetsStartSym = Sym; }
169 
170   MCSymbol *getRnglistsTableBaseSym() const { return RnglistsTableBaseSym; }
171   void setRnglistsTableBaseSym(MCSymbol *Sym) { RnglistsTableBaseSym = Sym; }
172 
173   MCSymbol *getLoclistsTableBaseSym() const { return LoclistsTableBaseSym; }
174   void setLoclistsTableBaseSym(MCSymbol *Sym) { LoclistsTableBaseSym = Sym; }
175 
176   /// \returns false if the variable was merged with a previous one.
177   bool addScopeVariable(LexicalScope *LS, DbgVariable *Var);
178 
179   void addScopeLabel(LexicalScope *LS, DbgLabel *Label);
180 
181   DenseMap<LexicalScope *, ScopeVars> &getScopeVariables() {
182     return ScopeVariables;
183   }
184 
185   DenseMap<LexicalScope *, LabelList> &getScopeLabels() {
186     return ScopeLabels;
187   }
188 
189   DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
190     return AbstractSPDies;
191   }
192 
193   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
194     return AbstractEntities;
195   }
196 
197   void insertDIE(const MDNode *TypeMD, DIE *Die) {
198     DITypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
199   }
200 
201   DIE *getDIE(const MDNode *TypeMD) {
202     return DITypeNodeToDieMap.lookup(TypeMD);
203   }
204 };
205 
206 } // end namespace llvm
207 
208 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFFILE_H
209