lib/Target/BPF/BTFDebug.h

   1 //===- BTFDebug.h -----------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// This file contains support for writing BTF debug info.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_TARGET_BPF_BTFDEBUG_H
  15 #define LLVM_LIB_TARGET_BPF_BTFDEBUG_H
  16
  17 #include "llvm/ADT/StringMap.h"
  18 #include "llvm/CodeGen/DebugHandlerBase.h"
  19 #include <unordered_map>
  20 #include "BTF.h"
  21
  22 namespace llvm {
  23
  24 class AsmPrinter;
  25 class BTFDebug;
  26 class DIType;
  27 class MCStreamer;
  28 class MCSymbol;
  29 class MachineFunction;
  30
  31 /// The base class for BTF type generation.
  32 class BTFTypeBase {
  33 protected:
  34   uint8_t Kind;
  35   bool IsCompleted;
  36   uint32_t Id;
  37   struct BTF::CommonType BTFType;
  38
  39 public:
  40   BTFTypeBase() : IsCompleted(false) {}
  41   virtual ~BTFTypeBase() = default;
  42   void setId(uint32_t Id) { this->Id = Id; }
  43   uint32_t getId() { return Id; }
  44   uint32_t roundupToBytes(uint32_t NumBits) { return (NumBits + 7) >> 3; }
  45   /// Get the size of this BTF type entry.
  46   virtual uint32_t getSize() { return BTF::CommonTypeSize; }
  47   /// Complete BTF type generation after all related DebugInfo types
  48   /// have been visited so their BTF type id's are available
  49   /// for cross referece.
  50   virtual void completeType(BTFDebug &BDebug) {}
  51   /// Emit types for this BTF type entry.
  52   virtual void emitType(MCStreamer &OS);
  53 };
  54
  55 /// Handle several derived types include pointer, const,
  56 /// volatile, typedef and restrict.
  57 class BTFTypeDerived : public BTFTypeBase {
  58   const DIDerivedType *DTy;
  59   bool NeedsFixup;
  60
  61 public:
  62   BTFTypeDerived(const DIDerivedType *Ty, unsigned Tag, bool NeedsFixup);
  63   void completeType(BTFDebug &BDebug);
  64   void emitType(MCStreamer &OS);
  65   void setPointeeType(uint32_t PointeeType);
  66 };
  67
  68 /// Handle struct or union forward declaration.
  69 class BTFTypeFwd : public BTFTypeBase {
  70   StringRef Name;
  71
  72 public:
  73   BTFTypeFwd(StringRef Name, bool IsUnion);
  74   void completeType(BTFDebug &BDebug);
  75   void emitType(MCStreamer &OS);
  76 };
  77
  78 /// Handle int type.
  79 class BTFTypeInt : public BTFTypeBase {
  80   StringRef Name;
  81   uint32_t IntVal; ///< Encoding, offset, bits
  82
  83 public:
  84   BTFTypeInt(uint32_t Encoding, uint32_t SizeInBits, uint32_t OffsetInBits,
  85              StringRef TypeName);
  86   uint32_t getSize() { return BTFTypeBase::getSize() + sizeof(uint32_t); }
  87   void completeType(BTFDebug &BDebug);
  88   void emitType(MCStreamer &OS);
  89 };
  90
  91 /// Handle enumerate type.
  92 class BTFTypeEnum : public BTFTypeBase {
  93   const DICompositeType *ETy;
  94   std::vector<struct BTF::BTFEnum> EnumValues;
  95
  96 public:
  97   BTFTypeEnum(const DICompositeType *ETy, uint32_t NumValues);
  98   uint32_t getSize() {
  99     return BTFTypeBase::getSize() + EnumValues.size() * BTF::BTFEnumSize;
 100   }
 101   void completeType(BTFDebug &BDebug);
 102   void emitType(MCStreamer &OS);
 103 };
 104
 105 /// Handle array type.
 106 class BTFTypeArray : public BTFTypeBase {
 107   struct BTF::BTFArray ArrayInfo;
 108
 109 public:
 110   BTFTypeArray(uint32_t ElemTypeId, uint32_t NumElems);
 111   uint32_t getSize() { return BTFTypeBase::getSize() + BTF::BTFArraySize; }
 112   void completeType(BTFDebug &BDebug);
 113   void emitType(MCStreamer &OS);
 114 };
 115
 116 /// Handle struct/union type.
 117 class BTFTypeStruct : public BTFTypeBase {
 118   const DICompositeType *STy;
 119   bool HasBitField;
 120   std::vector<struct BTF::BTFMember> Members;
 121
 122 public:
 123   BTFTypeStruct(const DICompositeType *STy, bool IsStruct, bool HasBitField,
 124                 uint32_t NumMembers);
 125   uint32_t getSize() {
 126     return BTFTypeBase::getSize() + Members.size() * BTF::BTFMemberSize;
 127   }
 128   void completeType(BTFDebug &BDebug);
 129   void emitType(MCStreamer &OS);
 130   std::string getName();
 131 };
 132
 133 /// Handle function pointer.
 134 class BTFTypeFuncProto : public BTFTypeBase {
 135   const DISubroutineType *STy;
 136   std::unordered_map<uint32_t, StringRef> FuncArgNames;
 137   std::vector<struct BTF::BTFParam> Parameters;
 138
 139 public:
 140   BTFTypeFuncProto(const DISubroutineType *STy, uint32_t NumParams,
 141                    const std::unordered_map<uint32_t, StringRef> &FuncArgNames);
 142   uint32_t getSize() {
 143     return BTFTypeBase::getSize() + Parameters.size() * BTF::BTFParamSize;
 144   }
 145   void completeType(BTFDebug &BDebug);
 146   void emitType(MCStreamer &OS);
 147 };
 148
 149 /// Handle subprogram
 150 class BTFTypeFunc : public BTFTypeBase {
 151   StringRef Name;
 152
 153 public:
 154   BTFTypeFunc(StringRef FuncName, uint32_t ProtoTypeId);
 155   uint32_t getSize() { return BTFTypeBase::getSize(); }
 156   void completeType(BTFDebug &BDebug);
 157   void emitType(MCStreamer &OS);
 158 };
 159
 160 /// Handle variable instances
 161 class BTFKindVar : public BTFTypeBase {
 162   StringRef Name;
 163   uint32_t Info;
 164
 165 public:
 166   BTFKindVar(StringRef VarName, uint32_t TypeId, uint32_t VarInfo);
 167   uint32_t getSize() { return BTFTypeBase::getSize() + 4; }
 168   void completeType(BTFDebug &BDebug);
 169   void emitType(MCStreamer &OS);
 170 };
 171
 172 /// Handle data sections
 173 class BTFKindDataSec : public BTFTypeBase {
 174   AsmPrinter *Asm;
 175   std::string Name;
 176   std::vector<std::tuple<uint32_t, const MCSymbol *, uint32_t>> Vars;
 177
 178 public:
 179   BTFKindDataSec(AsmPrinter *AsmPrt, std::string SecName);
 180   uint32_t getSize() {
 181     return BTFTypeBase::getSize() + BTF::BTFDataSecVarSize * Vars.size();
 182   }
 183   void addVar(uint32_t Id, const MCSymbol *Sym, uint32_t Size) {
 184     Vars.push_back(std::make_tuple(Id, Sym, Size));
 185   }
 186   std::string getName() { return Name; }
 187   void completeType(BTFDebug &BDebug);
 188   void emitType(MCStreamer &OS);
 189 };
 190
 191 /// String table.
 192 class BTFStringTable {
 193   /// String table size in bytes.
 194   uint32_t Size;
 195   /// A mapping from string table offset to the index
 196   /// of the Table. It is used to avoid putting
 197   /// duplicated strings in the table.
 198   std::map<uint32_t, uint32_t> OffsetToIdMap;
 199   /// A vector of strings to represent the string table.
 200   std::vector<std::string> Table;
 201
 202 public:
 203   BTFStringTable() : Size(0) {}
 204   uint32_t getSize() { return Size; }
 205   std::vector<std::string> &getTable() { return Table; }
 206   /// Add a string to the string table and returns its offset
 207   /// in the table.
 208   uint32_t addString(StringRef S);
 209 };
 210
 211 /// Represent one func and its type id.
 212 struct BTFFuncInfo {
 213   const MCSymbol *Label; ///< Func MCSymbol
 214   uint32_t TypeId;       ///< Type id referring to .BTF type section
 215 };
 216
 217 /// Represent one line info.
 218 struct BTFLineInfo {
 219   MCSymbol *Label;      ///< MCSymbol identifying insn for the lineinfo
 220   uint32_t FileNameOff; ///< file name offset in the .BTF string table
 221   uint32_t LineOff;     ///< line offset in the .BTF string table
 222   uint32_t LineNum;     ///< the line number
 223   uint32_t ColumnNum;   ///< the column number
 224 };
 225
 226 /// Represent one offset relocation.
 227 struct BTFFieldReloc {
 228   const MCSymbol *Label;  ///< MCSymbol identifying insn for the reloc
 229   uint32_t TypeID;        ///< Type ID
 230   uint32_t OffsetNameOff; ///< The string to traverse types
 231   uint32_t RelocKind;     ///< What to patch the instruction
 232 };
 233
 234 /// Collect and emit BTF information.
 235 class BTFDebug : public DebugHandlerBase {
 236   MCStreamer &OS;
 237   bool SkipInstruction;
 238   bool LineInfoGenerated;
 239   uint32_t SecNameOff;
 240   uint32_t ArrayIndexTypeId;
 241   bool MapDefNotCollected;
 242   BTFStringTable StringTable;
 243   std::vector<std::unique_ptr<BTFTypeBase>> TypeEntries;
 244   std::unordered_map<const DIType *, uint32_t> DIToIdMap;
 245   std::map<uint32_t, std::vector<BTFFuncInfo>> FuncInfoTable;
 246   std::map<uint32_t, std::vector<BTFLineInfo>> LineInfoTable;
 247   std::map<uint32_t, std::vector<BTFFieldReloc>> FieldRelocTable;
 248   StringMap<std::vector<std::string>> FileContent;
 249   std::map<std::string, std::unique_ptr<BTFKindDataSec>> DataSecEntries;
 250   std::vector<BTFTypeStruct *> StructTypes;
 251   std::map<std::string, uint32_t> PatchImms;
 252   std::map<StringRef, std::pair<bool, std::vector<BTFTypeDerived *>>>
 253       FixupDerivedTypes;
 254
 255   /// Add types to TypeEntries.
 256   /// @{
 257   /// Add types to TypeEntries and DIToIdMap.
 258   uint32_t addType(std::unique_ptr<BTFTypeBase> TypeEntry, const DIType *Ty);
 259   /// Add types to TypeEntries only and return type id.
 260   uint32_t addType(std::unique_ptr<BTFTypeBase> TypeEntry);
 261   /// @}
 262
 263   /// IR type visiting functions.
 264   /// @{
 265   void visitTypeEntry(const DIType *Ty);
 266   void visitTypeEntry(const DIType *Ty, uint32_t &TypeId, bool CheckPointer,
 267                       bool SeenPointer);
 268   void visitBasicType(const DIBasicType *BTy, uint32_t &TypeId);
 269   void visitSubroutineType(
 270       const DISubroutineType *STy, bool ForSubprog,
 271       const std::unordered_map<uint32_t, StringRef> &FuncArgNames,
 272       uint32_t &TypeId);
 273   void visitFwdDeclType(const DICompositeType *CTy, bool IsUnion,
 274                         uint32_t &TypeId);
 275   void visitCompositeType(const DICompositeType *CTy, uint32_t &TypeId);
 276   void visitStructType(const DICompositeType *STy, bool IsStruct,
 277                        uint32_t &TypeId);
 278   void visitArrayType(const DICompositeType *ATy, uint32_t &TypeId);
 279   void visitEnumType(const DICompositeType *ETy, uint32_t &TypeId);
 280   void visitDerivedType(const DIDerivedType *DTy, uint32_t &TypeId,
 281                         bool CheckPointer, bool SeenPointer);
 282   void visitMapDefType(const DIType *Ty, uint32_t &TypeId);
 283   /// @}
 284
 285   /// Get the file content for the subprogram. Certain lines of the file
 286   /// later may be put into string table and referenced by line info.
 287   std::string populateFileContent(const DISubprogram *SP);
 288
 289   /// Construct a line info.
 290   void constructLineInfo(const DISubprogram *SP, MCSymbol *Label, uint32_t Line,
 291                          uint32_t Column);
 292
 293   /// Generate types and variables for globals.
 294   void processGlobals(bool ProcessingMapDef);
 295
 296   /// Generate one offset relocation record.
 297   void generateFieldReloc(const MachineInstr *MI, const MCSymbol *ORSym,
 298                            DIType *RootTy, StringRef AccessPattern);
 299
 300   /// Populating unprocessed struct type.
 301   unsigned populateStructType(const DIType *Ty);
 302
 303   /// Process LD_imm64 instructions.
 304   void processLDimm64(const MachineInstr *MI);
 305
 306   /// Emit common header of .BTF and .BTF.ext sections.
 307   void emitCommonHeader();
 308
 309   /// Emit the .BTF section.
 310   void emitBTFSection();
 311
 312   /// Emit the .BTF.ext section.
 313   void emitBTFExtSection();
 314
 315 protected:
 316   /// Gather pre-function debug information.
 317   void beginFunctionImpl(const MachineFunction *MF) override;
 318
 319   /// Post process after all instructions in this function are processed.
 320   void endFunctionImpl(const MachineFunction *MF) override;
 321
 322 public:
 323   BTFDebug(AsmPrinter *AP);
 324
 325   ///
 326   bool InstLower(const MachineInstr *MI, MCInst &OutMI);
 327
 328   /// Get the special array index type id.
 329   uint32_t getArrayIndexTypeId() {
 330     assert(ArrayIndexTypeId);
 331     return ArrayIndexTypeId;
 332   }
 333
 334   /// Add string to the string table.
 335   size_t addString(StringRef S) { return StringTable.addString(S); }
 336
 337   /// Get the type id for a particular DIType.
 338   uint32_t getTypeId(const DIType *Ty) {
 339     assert(Ty && "Invalid null Type");
 340     assert(DIToIdMap.find(Ty) != DIToIdMap.end() &&
 341            "DIType not added in the BDIToIdMap");
 342     return DIToIdMap[Ty];
 343   }
 344
 345   void setSymbolSize(const MCSymbol *Symbol, uint64_t Size) override {}
 346
 347   /// Process beginning of an instruction.
 348   void beginInstruction(const MachineInstr *MI) override;
 349
 350   /// Complete all the types and emit the BTF sections.
 351   void endModule() override;
 352 };
 353
 354 } // end namespace llvm
 355
 356 #endif