1 //===-- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h ----*- 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 // This file contains support for writing Microsoft CodeView debug info.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_CODEVIEWDEBUG_H
15 #define LLVM_LIB_CODEGEN_ASMPRINTER_CODEVIEWDEBUG_H
16 
17 #include "DebugHandlerBase.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/ADT/StringRef.h"
21 #include "llvm/CodeGen/AsmPrinter.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineModuleInfo.h"
24 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
25 #include "llvm/IR/DebugInfo.h"
26 #include "llvm/IR/DebugLoc.h"
27 #include "llvm/MC/MCStreamer.h"
28 #include "llvm/Target/TargetLoweringObjectFile.h"
29 
30 namespace llvm {
31 
32 class LexicalScope;
33 
34 /// \brief Collects and handles line tables information in a CodeView format.
35 class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
36   MCStreamer &OS;
37 
38   /// Represents the most general definition range.
39   struct LocalVarDefRange {
40     /// Indicates that variable data is stored in memory relative to the
41     /// specified register.
42     int InMemory : 1;
43 
44     /// Offset of variable data in memory.
45     int DataOffset : 31;
46 
47     /// Offset of the data into the user level struct. If zero, no splitting
48     /// occurred.
49     uint16_t StructOffset;
50 
51     /// Register containing the data or the register base of the memory
52     /// location containing the data.
53     uint16_t CVRegister;
54 
55     /// Compares all location fields. This includes all fields except the label
56     /// ranges.
57     bool isDifferentLocation(LocalVarDefRange &O) {
58       return InMemory != O.InMemory || DataOffset != O.DataOffset ||
59              StructOffset != O.StructOffset || CVRegister != O.CVRegister;
60     }
61 
62     SmallVector<std::pair<const MCSymbol *, const MCSymbol *>, 1> Ranges;
63   };
64 
65   static LocalVarDefRange createDefRangeMem(uint16_t CVRegister, int Offset);
66   static LocalVarDefRange createDefRangeReg(uint16_t CVRegister);
67 
68   /// Similar to DbgVariable in DwarfDebug, but not dwarf-specific.
69   struct LocalVariable {
70     const DILocalVariable *DIVar = nullptr;
71     SmallVector<LocalVarDefRange, 1> DefRanges;
72   };
73 
74   struct InlineSite {
75     SmallVector<LocalVariable, 1> InlinedLocals;
76     SmallVector<const DILocation *, 1> ChildSites;
77     const DISubprogram *Inlinee = nullptr;
78     unsigned SiteFuncId = 0;
79   };
80 
81   // For each function, store a vector of labels to its instructions, as well as
82   // to the end of the function.
83   struct FunctionInfo {
84     /// Map from inlined call site to inlined instructions and child inlined
85     /// call sites. Listed in program order.
86     std::unordered_map<const DILocation *, InlineSite> InlineSites;
87 
88     /// Ordered list of top-level inlined call sites.
89     SmallVector<const DILocation *, 1> ChildSites;
90 
91     SmallVector<LocalVariable, 1> Locals;
92 
93     DebugLoc LastLoc;
94     const MCSymbol *Begin = nullptr;
95     const MCSymbol *End = nullptr;
96     unsigned FuncId = 0;
97     unsigned LastFileId = 0;
98     bool HaveLineInfo = false;
99   };
100   FunctionInfo *CurFn;
101 
102   unsigned NextFuncId = 0;
103 
104   InlineSite &getInlineSite(const DILocation *InlinedAt,
105                             const DISubprogram *Inlinee);
106 
107   static void collectInlineSiteChildren(SmallVectorImpl<unsigned> &Children,
108                                         const FunctionInfo &FI,
109                                         const InlineSite &Site);
110 
111   /// Remember some debug info about each function. Keep it in a stable order to
112   /// emit at the end of the TU.
113   MapVector<const Function *, FunctionInfo> FnDebugInfo;
114 
115   /// Map from DIFile to .cv_file id.
116   DenseMap<const DIFile *, unsigned> FileIdMap;
117 
118   SmallSetVector<const DISubprogram *, 4> InlinedSubprograms;
119 
120   DenseMap<const DISubprogram *, codeview::TypeIndex> SubprogramToFuncId;
121 
122   unsigned TypeCount = 0;
123 
124   /// Gets the next type index and increments the count of types streamed so
125   /// far.
126   codeview::TypeIndex getNextTypeIndex() {
127     return codeview::TypeIndex(codeview::TypeIndex::FirstNonSimpleIndex + TypeCount++);
128   }
129 
130   typedef std::map<const DIFile *, std::string> FileToFilepathMapTy;
131   FileToFilepathMapTy FileToFilepathMap;
132   StringRef getFullFilepath(const DIFile *S);
133 
134   unsigned maybeRecordFile(const DIFile *F);
135 
136   void maybeRecordLocation(DebugLoc DL, const MachineFunction *MF);
137 
138   void clear() {
139     assert(CurFn == nullptr);
140     FileIdMap.clear();
141     FnDebugInfo.clear();
142     FileToFilepathMap.clear();
143   }
144 
145   void emitTypeInformation();
146 
147   void emitInlineeLinesSubsection();
148 
149   void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
150 
151   void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
152                            const InlineSite &Site);
153 
154   typedef DbgValueHistoryMap::InlinedVariable InlinedVariable;
155 
156   void collectVariableInfo(const DISubprogram *SP);
157 
158   void collectVariableInfoFromMMITable(DenseSet<InlinedVariable> &Processed);
159 
160   /// Records information about a local variable in the appropriate scope. In
161   /// particular, locals from inlined code live inside the inlining site.
162   void recordLocalVariable(LocalVariable &&Var, const DILocation *Loc);
163 
164   void emitLocalVariable(const LocalVariable &Var);
165 
166 public:
167   CodeViewDebug(AsmPrinter *Asm);
168 
169   void setSymbolSize(const llvm::MCSymbol *, uint64_t) override {}
170 
171   /// \brief Emit the COFF section that holds the line table information.
172   void endModule() override;
173 
174   /// \brief Gather pre-function debug information.
175   void beginFunction(const MachineFunction *MF) override;
176 
177   /// \brief Gather post-function debug information.
178   void endFunction(const MachineFunction *) override;
179 
180   /// \brief Process beginning of an instruction.
181   void beginInstruction(const MachineInstr *MI) override;
182 };
183 } // End of namespace llvm
184 
185 #endif
186