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/CodeGen/AsmPrinter.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineModuleInfo.h"
23 #include "llvm/DebugInfo/CodeView/MemoryTypeTableBuilder.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 StringRef;
33 class LexicalScope;
34 struct ClassInfo;
35 
36 /// \brief Collects and handles line tables information in a CodeView format.
37 class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
38   MCStreamer &OS;
39   codeview::MemoryTypeTableBuilder TypeTable;
40 
41   /// Represents the most general definition range.
42   struct LocalVarDefRange {
43     /// Indicates that variable data is stored in memory relative to the
44     /// specified register.
45     int InMemory : 1;
46 
47     /// Offset of variable data in memory.
48     int DataOffset : 31;
49 
50     /// Offset of the data into the user level struct. If zero, no splitting
51     /// occurred.
52     uint16_t StructOffset;
53 
54     /// Register containing the data or the register base of the memory
55     /// location containing the data.
56     uint16_t CVRegister;
57 
58     /// Compares all location fields. This includes all fields except the label
59     /// ranges.
60     bool isDifferentLocation(LocalVarDefRange &O) {
61       return InMemory != O.InMemory || DataOffset != O.DataOffset ||
62              StructOffset != O.StructOffset || CVRegister != O.CVRegister;
63     }
64 
65     SmallVector<std::pair<const MCSymbol *, const MCSymbol *>, 1> Ranges;
66   };
67 
68   static LocalVarDefRange createDefRangeMem(uint16_t CVRegister, int Offset);
69   static LocalVarDefRange createDefRangeReg(uint16_t CVRegister);
70 
71   /// Similar to DbgVariable in DwarfDebug, but not dwarf-specific.
72   struct LocalVariable {
73     const DILocalVariable *DIVar = nullptr;
74     SmallVector<LocalVarDefRange, 1> DefRanges;
75   };
76 
77   struct InlineSite {
78     SmallVector<LocalVariable, 1> InlinedLocals;
79     SmallVector<const DILocation *, 1> ChildSites;
80     const DISubprogram *Inlinee = nullptr;
81     unsigned SiteFuncId = 0;
82   };
83 
84   // For each function, store a vector of labels to its instructions, as well as
85   // to the end of the function.
86   struct FunctionInfo {
87     /// Map from inlined call site to inlined instructions and child inlined
88     /// call sites. Listed in program order.
89     std::unordered_map<const DILocation *, InlineSite> InlineSites;
90 
91     /// Ordered list of top-level inlined call sites.
92     SmallVector<const DILocation *, 1> ChildSites;
93 
94     SmallVector<LocalVariable, 1> Locals;
95 
96     DebugLoc LastLoc;
97     const MCSymbol *Begin = nullptr;
98     const MCSymbol *End = nullptr;
99     unsigned FuncId = 0;
100     unsigned LastFileId = 0;
101     bool HaveLineInfo = false;
102   };
103   FunctionInfo *CurFn;
104 
105   /// The set of comdat .debug$S sections that we've seen so far. Each section
106   /// must start with a magic version number that must only be emitted once.
107   /// This set tracks which sections we've already opened.
108   DenseSet<MCSectionCOFF *> ComdatDebugSections;
109 
110   /// Switch to the appropriate .debug$S section for GVSym. If GVSym, the symbol
111   /// of an emitted global value, is in a comdat COFF section, this will switch
112   /// to a new .debug$S section in that comdat. This method ensures that the
113   /// section starts with the magic version number on first use. If GVSym is
114   /// null, uses the main .debug$S section.
115   void switchToDebugSectionForSymbol(const MCSymbol *GVSym);
116 
117   /// The next available function index for use with our .cv_* directives. Not
118   /// to be confused with type indices for LF_FUNC_ID records.
119   unsigned NextFuncId = 0;
120 
121   InlineSite &getInlineSite(const DILocation *InlinedAt,
122                             const DISubprogram *Inlinee);
123 
124   codeview::TypeIndex getFuncIdForSubprogram(const DISubprogram *SP);
125 
126   static void collectInlineSiteChildren(SmallVectorImpl<unsigned> &Children,
127                                         const FunctionInfo &FI,
128                                         const InlineSite &Site);
129 
130   /// Remember some debug info about each function. Keep it in a stable order to
131   /// emit at the end of the TU.
132   MapVector<const Function *, FunctionInfo> FnDebugInfo;
133 
134   /// Map from DIFile to .cv_file id.
135   DenseMap<const DIFile *, unsigned> FileIdMap;
136 
137   /// All inlined subprograms in the order they should be emitted.
138   SmallSetVector<const DISubprogram *, 4> InlinedSubprograms;
139 
140   /// Map from a pair of DI metadata nodes and its DI type (or scope) that can
141   /// be nullptr, to CodeView type indices. Primarily indexed by
142   /// {DIType*, DIType*} and {DISubprogram*, DIType*}.
143   ///
144   /// The second entry in the key is needed for methods as DISubroutineType
145   /// representing static method type are shared with non-method function type.
146   DenseMap<std::pair<const DINode *, const DIType *>, codeview::TypeIndex>
147       TypeIndices;
148 
149   /// Map from DICompositeType* to complete type index. Non-record types are
150   /// always looked up in the normal TypeIndices map.
151   DenseMap<const DICompositeType *, codeview::TypeIndex> CompleteTypeIndices;
152 
153   /// Map from DICompositeType* to class info.
154   DenseMap<const DICompositeType *, std::unique_ptr<ClassInfo>> ClassInfoMap;
155   const DISubprogram *CurrentSubprogram = nullptr;
156 
157   // The UDTs we have seen while processing types; each entry is a pair of type
158   // index and type name.
159   std::vector<std::pair<std::string, codeview::TypeIndex>> LocalUDTs,
160       GlobalUDTs;
161 
162   typedef std::map<const DIFile *, std::string> FileToFilepathMapTy;
163   FileToFilepathMapTy FileToFilepathMap;
164   StringRef getFullFilepath(const DIFile *S);
165 
166   unsigned maybeRecordFile(const DIFile *F);
167 
168   void maybeRecordLocation(const DebugLoc &DL, const MachineFunction *MF);
169 
170   void clear();
171 
172   void setCurrentSubprogram(const DISubprogram *SP) {
173     CurrentSubprogram = SP;
174     LocalUDTs.clear();
175   }
176 
177   /// Emit the magic version number at the start of a CodeView type or symbol
178   /// section. Appears at the front of every .debug$S or .debug$T section.
179   void emitCodeViewMagicVersion();
180 
181   void emitTypeInformation();
182 
183   void emitInlineeLinesSubsection();
184 
185   void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
186 
187   void emitDebugInfoForGlobals();
188 
189   void emitDebugInfoForUDTs(
190       ArrayRef<std::pair<std::string, codeview::TypeIndex>> UDTs);
191 
192   void emitDebugInfoForGlobal(const DIGlobalVariable *DIGV, MCSymbol *GVSym);
193 
194   /// Opens a subsection of the given kind in a .debug$S codeview section.
195   /// Returns an end label for use with endCVSubsection when the subsection is
196   /// finished.
197   MCSymbol *beginCVSubsection(codeview::ModuleSubstreamKind Kind);
198 
199   void endCVSubsection(MCSymbol *EndLabel);
200 
201   void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
202                            const InlineSite &Site);
203 
204   typedef DbgValueHistoryMap::InlinedVariable InlinedVariable;
205 
206   void collectVariableInfo(const DISubprogram *SP);
207 
208   void collectVariableInfoFromMMITable(DenseSet<InlinedVariable> &Processed);
209 
210   /// Records information about a local variable in the appropriate scope. In
211   /// particular, locals from inlined code live inside the inlining site.
212   void recordLocalVariable(LocalVariable &&Var, const DILocation *Loc);
213 
214   void emitLocalVariable(const LocalVariable &Var);
215 
216   /// Translates the DIType to codeview if necessary and returns a type index
217   /// for it.
218   codeview::TypeIndex getTypeIndex(DITypeRef TypeRef,
219                                    DITypeRef ClassTyRef = DITypeRef());
220 
221   codeview::TypeIndex lowerType(const DIType *Ty, const DIType *ClassTy);
222   codeview::TypeIndex lowerTypeAlias(const DIDerivedType *Ty);
223   codeview::TypeIndex lowerTypeArray(const DICompositeType *Ty);
224   codeview::TypeIndex lowerTypeBasic(const DIBasicType *Ty);
225   codeview::TypeIndex lowerTypePointer(const DIDerivedType *Ty);
226   codeview::TypeIndex lowerTypeMemberPointer(const DIDerivedType *Ty);
227   codeview::TypeIndex lowerTypeModifier(const DIDerivedType *Ty);
228   codeview::TypeIndex lowerTypeFunction(const DISubroutineType *Ty);
229   codeview::TypeIndex lowerTypeMemberFunction(const DISubroutineType *Ty,
230                                               const DIType *ClassTy);
231   codeview::TypeIndex lowerTypeEnum(const DICompositeType *Ty);
232   codeview::TypeIndex lowerTypeClass(const DICompositeType *Ty);
233   codeview::TypeIndex lowerTypeUnion(const DICompositeType *Ty);
234 
235   /// Symbol records should point to complete types, but type records should
236   /// always point to incomplete types to avoid cycles in the type graph. Only
237   /// use this entry point when generating symbol records. The complete and
238   /// incomplete type indices only differ for record types. All other types use
239   /// the same index.
240   codeview::TypeIndex getCompleteTypeIndex(DITypeRef TypeRef);
241 
242   codeview::TypeIndex lowerCompleteTypeClass(const DICompositeType *Ty);
243   codeview::TypeIndex lowerCompleteTypeUnion(const DICompositeType *Ty);
244 
245   codeview::TypeIndex lowerSubprogramType(const DISubprogram *SP);
246 
247   void collectMemberInfo(ClassInfo &Info, const DIDerivedType *DDTy);
248   ClassInfo &collectClassInfo(const DICompositeType *Ty);
249 
250   /// Common record member lowering functionality for record types, which are
251   /// structs, classes, and unions. Returns the field list index and the member
252   /// count.
253   std::tuple<codeview::TypeIndex, codeview::TypeIndex, unsigned>
254   lowerRecordFieldList(const DICompositeType *Ty);
255 
256   /// Inserts {{Node, ClassTy}, TI} into TypeIndices and checks for duplicates.
257   void recordTypeIndexForDINode(const DINode *Node, codeview::TypeIndex TI,
258                                 const DIType *ClassTy = nullptr);
259 
260   unsigned getPointerSizeInBytes();
261 
262 public:
263   CodeViewDebug(AsmPrinter *Asm);
264 
265   void setSymbolSize(const llvm::MCSymbol *, uint64_t) override {}
266 
267   /// \brief Emit the COFF section that holds the line table information.
268   void endModule() override;
269 
270   /// \brief Gather pre-function debug information.
271   void beginFunction(const MachineFunction *MF) override;
272 
273   /// \brief Gather post-function debug information.
274   void endFunction(const MachineFunction *) override;
275 
276   /// \brief Process beginning of an instruction.
277   void beginInstruction(const MachineInstr *MI) override;
278 };
279 } // End of namespace llvm
280 
281 #endif
282