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 "DbgValueHistoryCalculator.h"
18 #include "DebugHandlerBase.h"
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/DenseSet.h"
22 #include "llvm/ADT/MapVector.h"
23 #include "llvm/ADT/SetVector.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/DebugInfo/CodeView/CodeView.h"
26 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
27 #include "llvm/DebugInfo/CodeView/TypeTableBuilder.h"
28 #include "llvm/IR/DebugLoc.h"
29 #include "llvm/Support/Allocator.h"
30 #include "llvm/Support/Compiler.h"
31 #include <cstdint>
32 #include <map>
33 #include <string>
34 #include <tuple>
35 #include <unordered_map>
36 #include <utility>
37 #include <vector>
38 
39 namespace llvm {
40 
41 struct ClassInfo;
42 class StringRef;
43 class AsmPrinter;
44 class Function;
45 class GlobalVariable;
46 class MCSectionCOFF;
47 class MCStreamer;
48 class MCSymbol;
49 class MachineFunction;
50 
51 /// \brief Collects and handles line tables information in a CodeView format.
52 class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
53   MCStreamer &OS;
54   BumpPtrAllocator Allocator;
55   codeview::TypeTableBuilder TypeTable;
56 
57   /// Represents the most general definition range.
58   struct LocalVarDefRange {
59     /// Indicates that variable data is stored in memory relative to the
60     /// specified register.
61     int InMemory : 1;
62 
63     /// Offset of variable data in memory.
64     int DataOffset : 31;
65 
66     /// Non-zero if this is a piece of an aggregate.
67     uint16_t IsSubfield : 1;
68 
69     /// Offset into aggregate.
70     uint16_t StructOffset : 15;
71 
72     /// Register containing the data or the register base of the memory
73     /// location containing the data.
74     uint16_t CVRegister;
75 
76     /// Compares all location fields. This includes all fields except the label
77     /// ranges.
78     bool isDifferentLocation(LocalVarDefRange &O) {
79       return InMemory != O.InMemory || DataOffset != O.DataOffset ||
80              IsSubfield != O.IsSubfield || StructOffset != O.StructOffset ||
81              CVRegister != O.CVRegister;
82     }
83 
84     SmallVector<std::pair<const MCSymbol *, const MCSymbol *>, 1> Ranges;
85   };
86 
87   static LocalVarDefRange createDefRangeMem(uint16_t CVRegister, int Offset);
88   static LocalVarDefRange createDefRangeGeneral(uint16_t CVRegister,
89                                                 bool InMemory, int Offset,
90                                                 bool IsSubfield,
91                                                 uint16_t StructOffset);
92 
93   /// Similar to DbgVariable in DwarfDebug, but not dwarf-specific.
94   struct LocalVariable {
95     const DILocalVariable *DIVar = nullptr;
96     SmallVector<LocalVarDefRange, 1> DefRanges;
97     bool UseReferenceType = false;
98   };
99 
100   struct InlineSite {
101     SmallVector<LocalVariable, 1> InlinedLocals;
102     SmallVector<const DILocation *, 1> ChildSites;
103     const DISubprogram *Inlinee = nullptr;
104 
105     /// The ID of the inline site or function used with .cv_loc. Not a type
106     /// index.
107     unsigned SiteFuncId = 0;
108   };
109 
110   // For each function, store a vector of labels to its instructions, as well as
111   // to the end of the function.
112   struct FunctionInfo {
113     /// Map from inlined call site to inlined instructions and child inlined
114     /// call sites. Listed in program order.
115     std::unordered_map<const DILocation *, InlineSite> InlineSites;
116 
117     /// Ordered list of top-level inlined call sites.
118     SmallVector<const DILocation *, 1> ChildSites;
119 
120     SmallVector<LocalVariable, 1> Locals;
121 
122     std::vector<std::pair<MCSymbol *, MDNode *>> Annotations;
123 
124     const MCSymbol *Begin = nullptr;
125     const MCSymbol *End = nullptr;
126     unsigned FuncId = 0;
127     unsigned LastFileId = 0;
128     bool HaveLineInfo = false;
129   };
130   FunctionInfo *CurFn = nullptr;
131 
132   /// The set of comdat .debug$S sections that we've seen so far. Each section
133   /// must start with a magic version number that must only be emitted once.
134   /// This set tracks which sections we've already opened.
135   DenseSet<MCSectionCOFF *> ComdatDebugSections;
136 
137   /// Switch to the appropriate .debug$S section for GVSym. If GVSym, the symbol
138   /// of an emitted global value, is in a comdat COFF section, this will switch
139   /// to a new .debug$S section in that comdat. This method ensures that the
140   /// section starts with the magic version number on first use. If GVSym is
141   /// null, uses the main .debug$S section.
142   void switchToDebugSectionForSymbol(const MCSymbol *GVSym);
143 
144   /// The next available function index for use with our .cv_* directives. Not
145   /// to be confused with type indices for LF_FUNC_ID records.
146   unsigned NextFuncId = 0;
147 
148   InlineSite &getInlineSite(const DILocation *InlinedAt,
149                             const DISubprogram *Inlinee);
150 
151   codeview::TypeIndex getFuncIdForSubprogram(const DISubprogram *SP);
152 
153   void calculateRanges(LocalVariable &Var,
154                        const DbgValueHistoryMap::InstrRanges &Ranges);
155 
156   static void collectInlineSiteChildren(SmallVectorImpl<unsigned> &Children,
157                                         const FunctionInfo &FI,
158                                         const InlineSite &Site);
159 
160   /// Remember some debug info about each function. Keep it in a stable order to
161   /// emit at the end of the TU.
162   MapVector<const Function *, FunctionInfo> FnDebugInfo;
163 
164   /// Map from DIFile to .cv_file id.
165   DenseMap<const DIFile *, unsigned> FileIdMap;
166 
167   /// All inlined subprograms in the order they should be emitted.
168   SmallSetVector<const DISubprogram *, 4> InlinedSubprograms;
169 
170   /// Map from a pair of DI metadata nodes and its DI type (or scope) that can
171   /// be nullptr, to CodeView type indices. Primarily indexed by
172   /// {DIType*, DIType*} and {DISubprogram*, DIType*}.
173   ///
174   /// The second entry in the key is needed for methods as DISubroutineType
175   /// representing static method type are shared with non-method function type.
176   DenseMap<std::pair<const DINode *, const DIType *>, codeview::TypeIndex>
177       TypeIndices;
178 
179   /// Map from DICompositeType* to complete type index. Non-record types are
180   /// always looked up in the normal TypeIndices map.
181   DenseMap<const DICompositeType *, codeview::TypeIndex> CompleteTypeIndices;
182 
183   /// Complete record types to emit after all active type lowerings are
184   /// finished.
185   SmallVector<const DICompositeType *, 4> DeferredCompleteTypes;
186 
187   /// Number of type lowering frames active on the stack.
188   unsigned TypeEmissionLevel = 0;
189 
190   codeview::TypeIndex VBPType;
191 
192   const DISubprogram *CurrentSubprogram = nullptr;
193 
194   // The UDTs we have seen while processing types; each entry is a pair of type
195   // index and type name.
196   std::vector<std::pair<std::string, const DIType *>> LocalUDTs;
197   std::vector<std::pair<std::string, const DIType *>> GlobalUDTs;
198 
199   using FileToFilepathMapTy = std::map<const DIFile *, std::string>;
200   FileToFilepathMapTy FileToFilepathMap;
201 
202   StringRef getFullFilepath(const DIFile *S);
203 
204   unsigned maybeRecordFile(const DIFile *F);
205 
206   void maybeRecordLocation(const DebugLoc &DL, const MachineFunction *MF);
207 
208   void clear();
209 
210   void setCurrentSubprogram(const DISubprogram *SP) {
211     CurrentSubprogram = SP;
212     LocalUDTs.clear();
213   }
214 
215   /// Emit the magic version number at the start of a CodeView type or symbol
216   /// section. Appears at the front of every .debug$S or .debug$T section.
217   void emitCodeViewMagicVersion();
218 
219   void emitTypeInformation();
220 
221   void emitCompilerInformation();
222 
223   void emitInlineeLinesSubsection();
224 
225   void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
226 
227   void emitDebugInfoForGlobals();
228 
229   void emitDebugInfoForRetainedTypes();
230 
231   void
232   emitDebugInfoForUDTs(ArrayRef<std::pair<std::string, const DIType *>> UDTs);
233 
234   void emitDebugInfoForGlobal(const DIGlobalVariable *DIGV,
235                               const GlobalVariable *GV, MCSymbol *GVSym);
236 
237   /// Opens a subsection of the given kind in a .debug$S codeview section.
238   /// Returns an end label for use with endCVSubsection when the subsection is
239   /// finished.
240   MCSymbol *beginCVSubsection(codeview::DebugSubsectionKind Kind);
241 
242   void endCVSubsection(MCSymbol *EndLabel);
243 
244   void emitInlinedCallSite(const FunctionInfo &FI, const DILocation *InlinedAt,
245                            const InlineSite &Site);
246 
247   using InlinedVariable = DbgValueHistoryMap::InlinedVariable;
248 
249   void collectVariableInfo(const DISubprogram *SP);
250 
251   void collectVariableInfoFromMFTable(DenseSet<InlinedVariable> &Processed);
252 
253   /// Records information about a local variable in the appropriate scope. In
254   /// particular, locals from inlined code live inside the inlining site.
255   void recordLocalVariable(LocalVariable &&Var, const DILocation *Loc);
256 
257   /// Emits local variables in the appropriate order.
258   void emitLocalVariableList(ArrayRef<LocalVariable> Locals);
259 
260   /// Emits an S_LOCAL record and its associated defined ranges.
261   void emitLocalVariable(const LocalVariable &Var);
262 
263   /// Translates the DIType to codeview if necessary and returns a type index
264   /// for it.
265   codeview::TypeIndex getTypeIndex(DITypeRef TypeRef,
266                                    DITypeRef ClassTyRef = DITypeRef());
267 
268   codeview::TypeIndex getTypeIndexForReferenceTo(DITypeRef TypeRef);
269 
270   codeview::TypeIndex getMemberFunctionType(const DISubprogram *SP,
271                                             const DICompositeType *Class);
272 
273   codeview::TypeIndex getScopeIndex(const DIScope *Scope);
274 
275   codeview::TypeIndex getVBPTypeIndex();
276 
277   void addToUDTs(const DIType *Ty);
278 
279   codeview::TypeIndex lowerType(const DIType *Ty, const DIType *ClassTy);
280   codeview::TypeIndex lowerTypeAlias(const DIDerivedType *Ty);
281   codeview::TypeIndex lowerTypeArray(const DICompositeType *Ty);
282   codeview::TypeIndex lowerTypeBasic(const DIBasicType *Ty);
283   codeview::TypeIndex lowerTypePointer(const DIDerivedType *Ty);
284   codeview::TypeIndex lowerTypeMemberPointer(const DIDerivedType *Ty);
285   codeview::TypeIndex lowerTypeModifier(const DIDerivedType *Ty);
286   codeview::TypeIndex lowerTypeFunction(const DISubroutineType *Ty);
287   codeview::TypeIndex lowerTypeVFTableShape(const DIDerivedType *Ty);
288   codeview::TypeIndex lowerTypeMemberFunction(const DISubroutineType *Ty,
289                                               const DIType *ClassTy,
290                                               int ThisAdjustment,
291                                               bool IsStaticMethod);
292   codeview::TypeIndex lowerTypeEnum(const DICompositeType *Ty);
293   codeview::TypeIndex lowerTypeClass(const DICompositeType *Ty);
294   codeview::TypeIndex lowerTypeUnion(const DICompositeType *Ty);
295 
296   /// Symbol records should point to complete types, but type records should
297   /// always point to incomplete types to avoid cycles in the type graph. Only
298   /// use this entry point when generating symbol records. The complete and
299   /// incomplete type indices only differ for record types. All other types use
300   /// the same index.
301   codeview::TypeIndex getCompleteTypeIndex(DITypeRef TypeRef);
302 
303   codeview::TypeIndex lowerCompleteTypeClass(const DICompositeType *Ty);
304   codeview::TypeIndex lowerCompleteTypeUnion(const DICompositeType *Ty);
305 
306   struct TypeLoweringScope;
307 
308   void emitDeferredCompleteTypes();
309 
310   void collectMemberInfo(ClassInfo &Info, const DIDerivedType *DDTy);
311   ClassInfo collectClassInfo(const DICompositeType *Ty);
312 
313   /// Common record member lowering functionality for record types, which are
314   /// structs, classes, and unions. Returns the field list index and the member
315   /// count.
316   std::tuple<codeview::TypeIndex, codeview::TypeIndex, unsigned, bool>
317   lowerRecordFieldList(const DICompositeType *Ty);
318 
319   /// Inserts {{Node, ClassTy}, TI} into TypeIndices and checks for duplicates.
320   codeview::TypeIndex recordTypeIndexForDINode(const DINode *Node,
321                                                codeview::TypeIndex TI,
322                                                const DIType *ClassTy = nullptr);
323 
324   unsigned getPointerSizeInBytes();
325 
326 protected:
327   /// \brief Gather pre-function debug information.
328   void beginFunctionImpl(const MachineFunction *MF) override;
329 
330   /// \brief Gather post-function debug information.
331   void endFunctionImpl(const MachineFunction *) override;
332 
333 public:
334   CodeViewDebug(AsmPrinter *Asm);
335 
336   void setSymbolSize(const MCSymbol *, uint64_t) override {}
337 
338   /// \brief Emit the COFF section that holds the line table information.
339   void endModule() override;
340 
341   /// \brief Process beginning of an instruction.
342   void beginInstruction(const MachineInstr *MI) override;
343 };
344 
345 } // end namespace llvm
346 
347 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_CODEVIEWDEBUG_H
348