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   llvm::BumpPtrAllocator Allocator;
40   codeview::MemoryTypeTableBuilder TypeTable;
41 
42   /// Represents the most general definition range.
43   struct LocalVarDefRange {
44     /// Indicates that variable data is stored in memory relative to the
45     /// specified register.
46     int InMemory : 1;
47 
48     /// Offset of variable data in memory.
49     int DataOffset : 31;
50 
51     /// Offset of the data into the user level struct. If zero, no splitting
52     /// occurred.
53     uint16_t StructOffset;
54 
55     /// Register containing the data or the register base of the memory
56     /// location containing the data.
57     uint16_t CVRegister;
58 
59     /// Compares all location fields. This includes all fields except the label
60     /// ranges.
61     bool isDifferentLocation(LocalVarDefRange &O) {
62       return InMemory != O.InMemory || DataOffset != O.DataOffset ||
63              StructOffset != O.StructOffset || CVRegister != O.CVRegister;
64     }
65 
66     SmallVector<std::pair<const MCSymbol *, const MCSymbol *>, 1> Ranges;
67   };
68 
69   static LocalVarDefRange createDefRangeMem(uint16_t CVRegister, int Offset);
70   static LocalVarDefRange createDefRangeReg(uint16_t CVRegister);
71 
72   /// Similar to DbgVariable in DwarfDebug, but not dwarf-specific.
73   struct LocalVariable {
74     const DILocalVariable *DIVar = nullptr;
75     SmallVector<LocalVarDefRange, 1> DefRanges;
76   };
77 
78   struct InlineSite {
79     SmallVector<LocalVariable, 1> InlinedLocals;
80     SmallVector<const DILocation *, 1> ChildSites;
81     const DISubprogram *Inlinee = nullptr;
82 
83     /// The ID of the inline site or function used with .cv_loc. Not a type
84     /// index.
85     unsigned SiteFuncId = 0;
86   };
87 
88   // For each function, store a vector of labels to its instructions, as well as
89   // to the end of the function.
90   struct FunctionInfo {
91     /// Map from inlined call site to inlined instructions and child inlined
92     /// call sites. Listed in program order.
93     std::unordered_map<const DILocation *, InlineSite> InlineSites;
94 
95     /// Ordered list of top-level inlined call sites.
96     SmallVector<const DILocation *, 1> ChildSites;
97 
98     SmallVector<LocalVariable, 1> Locals;
99 
100     DebugLoc LastLoc;
101     const MCSymbol *Begin = nullptr;
102     const MCSymbol *End = nullptr;
103     unsigned FuncId = 0;
104     unsigned LastFileId = 0;
105     bool HaveLineInfo = false;
106   };
107   FunctionInfo *CurFn;
108 
109   /// The set of comdat .debug$S sections that we've seen so far. Each section
110   /// must start with a magic version number that must only be emitted once.
111   /// This set tracks which sections we've already opened.
112   DenseSet<MCSectionCOFF *> ComdatDebugSections;
113 
114   /// Switch to the appropriate .debug$S section for GVSym. If GVSym, the symbol
115   /// of an emitted global value, is in a comdat COFF section, this will switch
116   /// to a new .debug$S section in that comdat. This method ensures that the
117   /// section starts with the magic version number on first use. If GVSym is
118   /// null, uses the main .debug$S section.
119   void switchToDebugSectionForSymbol(const MCSymbol *GVSym);
120 
121   /// The next available function index for use with our .cv_* directives. Not
122   /// to be confused with type indices for LF_FUNC_ID records.
123   unsigned NextFuncId = 0;
124 
125   InlineSite &getInlineSite(const DILocation *InlinedAt,
126                             const DISubprogram *Inlinee);
127 
128   codeview::TypeIndex getFuncIdForSubprogram(const DISubprogram *SP);
129 
130   static void collectInlineSiteChildren(SmallVectorImpl<unsigned> &Children,
131                                         const FunctionInfo &FI,
132                                         const InlineSite &Site);
133 
134   /// Remember some debug info about each function. Keep it in a stable order to
135   /// emit at the end of the TU.
136   MapVector<const Function *, FunctionInfo> FnDebugInfo;
137 
138   /// Map from DIFile to .cv_file id.
139   DenseMap<const DIFile *, unsigned> FileIdMap;
140 
141   /// All inlined subprograms in the order they should be emitted.
142   SmallSetVector<const DISubprogram *, 4> InlinedSubprograms;
143 
144   /// Map from a pair of DI metadata nodes and its DI type (or scope) that can
145   /// be nullptr, to CodeView type indices. Primarily indexed by
146   /// {DIType*, DIType*} and {DISubprogram*, DIType*}.
147   ///
148   /// The second entry in the key is needed for methods as DISubroutineType
149   /// representing static method type are shared with non-method function type.
150   DenseMap<std::pair<const DINode *, const DIType *>, codeview::TypeIndex>
151       TypeIndices;
152 
153   /// Map from DICompositeType* to complete type index. Non-record types are
154   /// always looked up in the normal TypeIndices map.
155   DenseMap<const DICompositeType *, codeview::TypeIndex> CompleteTypeIndices;
156 
157   /// Complete record types to emit after all active type lowerings are
158   /// finished.
159   SmallVector<const DICompositeType *, 4> DeferredCompleteTypes;
160 
161   /// Number of type lowering frames active on the stack.
162   unsigned TypeEmissionLevel = 0;
163 
164   codeview::TypeIndex VBPType;
165 
166   const DISubprogram *CurrentSubprogram = nullptr;
167 
168   // The UDTs we have seen while processing types; each entry is a pair of type
169   // index and type name.
170   std::vector<std::pair<std::string, codeview::TypeIndex>> LocalUDTs,
171       GlobalUDTs;
172 
173   typedef std::map<const DIFile *, std::string> FileToFilepathMapTy;
174   FileToFilepathMapTy FileToFilepathMap;
175   StringRef getFullFilepath(const DIFile *S);
176 
177   unsigned maybeRecordFile(const DIFile *F);
178 
179   void maybeRecordLocation(const DebugLoc &DL, const MachineFunction *MF);
180 
181   void clear();
182 
183   void setCurrentSubprogram(const DISubprogram *SP) {
184     CurrentSubprogram = SP;
185     LocalUDTs.clear();
186   }
187 
188   /// Emit the magic version number at the start of a CodeView type or symbol
189   /// section. Appears at the front of every .debug$S or .debug$T section.
190   void emitCodeViewMagicVersion();
191 
192   void emitTypeInformation();
193 
194   void emitCompilerInformation();
195 
196   void emitInlineeLinesSubsection();
197 
198   void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
199 
200   void emitDebugInfoForGlobals();
201 
202   void emitDebugInfoForRetainedTypes();
203 
204   void emitDebugInfoForUDTs(
205       ArrayRef<std::pair<std::string, codeview::TypeIndex>> UDTs);
206 
207   void emitDebugInfoForGlobal(const DIGlobalVariable *DIGV,
208                               const GlobalVariable *GV, MCSymbol *GVSym);
209 
210   /// Opens a subsection of the given kind in a .debug$S codeview section.
211   /// Returns an end label for use with endCVSubsection when the subsection is
212   /// finished.
213   MCSymbol *beginCVSubsection(codeview::ModuleSubstreamKind Kind);
214 
215   void endCVSubsection(MCSymbol *EndLabel);
216 
217   void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
218                            const InlineSite &Site);
219 
220   typedef DbgValueHistoryMap::InlinedVariable InlinedVariable;
221 
222   void collectVariableInfo(const DISubprogram *SP);
223 
224   void collectVariableInfoFromMMITable(DenseSet<InlinedVariable> &Processed);
225 
226   /// Records information about a local variable in the appropriate scope. In
227   /// particular, locals from inlined code live inside the inlining site.
228   void recordLocalVariable(LocalVariable &&Var, const DILocation *Loc);
229 
230   /// Emits local variables in the appropriate order.
231   void emitLocalVariableList(ArrayRef<LocalVariable> Locals);
232 
233   /// Emits an S_LOCAL record and its associated defined ranges.
234   void emitLocalVariable(const LocalVariable &Var);
235 
236   /// Translates the DIType to codeview if necessary and returns a type index
237   /// for it.
238   codeview::TypeIndex getTypeIndex(DITypeRef TypeRef,
239                                    DITypeRef ClassTyRef = DITypeRef());
240 
241   codeview::TypeIndex getMemberFunctionType(const DISubprogram *SP,
242                                             const DICompositeType *Class);
243 
244   codeview::TypeIndex getScopeIndex(const DIScope *Scope);
245 
246   codeview::TypeIndex getVBPTypeIndex();
247 
248   void addToUDTs(const DIType *Ty, codeview::TypeIndex TI);
249 
250   codeview::TypeIndex lowerType(const DIType *Ty, const DIType *ClassTy);
251   codeview::TypeIndex lowerTypeAlias(const DIDerivedType *Ty);
252   codeview::TypeIndex lowerTypeArray(const DICompositeType *Ty);
253   codeview::TypeIndex lowerTypeBasic(const DIBasicType *Ty);
254   codeview::TypeIndex lowerTypePointer(const DIDerivedType *Ty);
255   codeview::TypeIndex lowerTypeMemberPointer(const DIDerivedType *Ty);
256   codeview::TypeIndex lowerTypeModifier(const DIDerivedType *Ty);
257   codeview::TypeIndex lowerTypeFunction(const DISubroutineType *Ty);
258   codeview::TypeIndex lowerTypeVFTableShape(const DIDerivedType *Ty);
259   codeview::TypeIndex lowerTypeMemberFunction(const DISubroutineType *Ty,
260                                               const DIType *ClassTy,
261                                               int ThisAdjustment);
262   codeview::TypeIndex lowerTypeEnum(const DICompositeType *Ty);
263   codeview::TypeIndex lowerTypeClass(const DICompositeType *Ty);
264   codeview::TypeIndex lowerTypeUnion(const DICompositeType *Ty);
265 
266   /// Symbol records should point to complete types, but type records should
267   /// always point to incomplete types to avoid cycles in the type graph. Only
268   /// use this entry point when generating symbol records. The complete and
269   /// incomplete type indices only differ for record types. All other types use
270   /// the same index.
271   codeview::TypeIndex getCompleteTypeIndex(DITypeRef TypeRef);
272 
273   codeview::TypeIndex lowerCompleteTypeClass(const DICompositeType *Ty);
274   codeview::TypeIndex lowerCompleteTypeUnion(const DICompositeType *Ty);
275 
276   struct TypeLoweringScope;
277 
278   void emitDeferredCompleteTypes();
279 
280   void collectMemberInfo(ClassInfo &Info, const DIDerivedType *DDTy);
281   ClassInfo collectClassInfo(const DICompositeType *Ty);
282 
283   /// Common record member lowering functionality for record types, which are
284   /// structs, classes, and unions. Returns the field list index and the member
285   /// count.
286   std::tuple<codeview::TypeIndex, codeview::TypeIndex, unsigned, bool>
287   lowerRecordFieldList(const DICompositeType *Ty);
288 
289   /// Inserts {{Node, ClassTy}, TI} into TypeIndices and checks for duplicates.
290   codeview::TypeIndex recordTypeIndexForDINode(const DINode *Node,
291                                                codeview::TypeIndex TI,
292                                                const DIType *ClassTy = nullptr);
293 
294   unsigned getPointerSizeInBytes();
295 
296 public:
297   CodeViewDebug(AsmPrinter *Asm);
298 
299   void setSymbolSize(const llvm::MCSymbol *, uint64_t) override {}
300 
301   /// \brief Emit the COFF section that holds the line table information.
302   void endModule() override;
303 
304   /// \brief Gather pre-function debug information.
305   void beginFunction(const MachineFunction *MF) override;
306 
307   /// \brief Gather post-function debug information.
308   void endFunction(const MachineFunction *) override;
309 
310   /// \brief Process beginning of an instruction.
311   void beginInstruction(const MachineInstr *MI) override;
312 };
313 } // End of namespace llvm
314 
315 #endif
316