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 "llvm/DebugInfo/BTF/BTF.h"
20#include <cstdint>
21#include <map>
22#include <set>
23#include <unordered_map>
24
25namespace llvm {
26
27class AsmPrinter;
28class BTFDebug;
29class DIType;
30class GlobalVariable;
31class MachineFunction;
32class MachineInstr;
33class MachineOperand;
34class MCInst;
35class MCStreamer;
36class MCSymbol;
37
38/// The base class for BTF type generation.
39class BTFTypeBase {
40protected:
41 uint8_t Kind;
42 bool IsCompleted;
43 uint32_t Id;
44 struct BTF::CommonType BTFType;
45
46public:
47 BTFTypeBase() : IsCompleted(false) {}
48 virtual ~BTFTypeBase() = default;
49 void setId(uint32_t Id) { this->Id = Id; }
50 uint32_t getId() { return Id; }
51 uint32_t roundupToBytes(uint32_t NumBits) { return (NumBits + 7) >> 3; }
52 /// Get the size of this BTF type entry.
53 virtual uint32_t getSize() { return BTF::CommonTypeSize; }
54 /// Complete BTF type generation after all related DebugInfo types
55 /// have been visited so their BTF type id's are available
56 /// for cross referece.
57 virtual void completeType(BTFDebug &BDebug) {}
58 /// Emit types for this BTF type entry.
59 virtual void emitType(MCStreamer &OS);
60};
61
62/// Handle several derived types include pointer, const,
63/// volatile, typedef and restrict.
64class BTFTypeDerived : public BTFTypeBase {
65 const DIDerivedType *DTy;
66 bool NeedsFixup;
67 StringRef Name;
68
69public:
70 BTFTypeDerived(const DIDerivedType *Ty, unsigned Tag, bool NeedsFixup);
71 BTFTypeDerived(unsigned NextTypeId, unsigned Tag, StringRef Name);
72 void completeType(BTFDebug &BDebug) override;
73 void emitType(MCStreamer &OS) override;
74 void setPointeeType(uint32_t PointeeType);
75};
76
77/// Handle struct or union forward declaration.
78class BTFTypeFwd : public BTFTypeBase {
79 StringRef Name;
80
81public:
82 BTFTypeFwd(StringRef Name, bool IsUnion);
83 void completeType(BTFDebug &BDebug) override;
84 void emitType(MCStreamer &OS) override;
85};
86
87/// Handle int type.
88class BTFTypeInt : public BTFTypeBase {
89 StringRef Name;
90 uint32_t IntVal; ///< Encoding, offset, bits
91
92public:
93 BTFTypeInt(uint32_t Encoding, uint32_t SizeInBits, uint32_t OffsetInBits,
94 StringRef TypeName);
95 uint32_t getSize() override { return BTFTypeBase::getSize() + sizeof(uint32_t); }
96 void completeType(BTFDebug &BDebug) override;
97 void emitType(MCStreamer &OS) override;
98};
99
100/// Handle enumerate type.
101class BTFTypeEnum : public BTFTypeBase {
102 const DICompositeType *ETy;
103 std::vector<struct BTF::BTFEnum> EnumValues;
104
105public:
106 BTFTypeEnum(const DICompositeType *ETy, uint32_t NumValues, bool IsSigned);
107 uint32_t getSize() override {
108 return BTFTypeBase::getSize() + EnumValues.size() * BTF::BTFEnumSize;
109 }
110 void completeType(BTFDebug &BDebug) override;
111 void emitType(MCStreamer &OS) override;
112};
113
114/// Handle array type.
115class BTFTypeArray : public BTFTypeBase {
116 struct BTF::BTFArray ArrayInfo;
117
118public:
119 BTFTypeArray(uint32_t ElemTypeId, uint32_t NumElems);
120 uint32_t getSize() override { return BTFTypeBase::getSize() + BTF::BTFArraySize; }
121 void completeType(BTFDebug &BDebug) override;
122 void emitType(MCStreamer &OS) override;
123};
124
125/// Handle struct/union type.
126class BTFTypeStruct : public BTFTypeBase {
127 const DICompositeType *STy;
128 bool HasBitField;
129 std::vector<struct BTF::BTFMember> Members;
130
131public:
132 BTFTypeStruct(const DICompositeType *STy, bool IsStruct, bool HasBitField,
133 uint32_t NumMembers);
134 uint32_t getSize() override {
135 return BTFTypeBase::getSize() + Members.size() * BTF::BTFMemberSize;
136 }
137 void completeType(BTFDebug &BDebug) override;
138 void emitType(MCStreamer &OS) override;
139 std::string getName();
140};
141
142/// Handle function pointer.
143class BTFTypeFuncProto : public BTFTypeBase {
144 const DISubroutineType *STy;
145 std::unordered_map<uint32_t, StringRef> FuncArgNames;
146 std::vector<struct BTF::BTFParam> Parameters;
147
148public:
149 BTFTypeFuncProto(const DISubroutineType *STy, uint32_t NumParams,
150 const std::unordered_map<uint32_t, StringRef> &FuncArgNames);
151 uint32_t getSize() override {
152 return BTFTypeBase::getSize() + Parameters.size() * BTF::BTFParamSize;
153 }
154 void completeType(BTFDebug &BDebug) override;
155 void emitType(MCStreamer &OS) override;
156};
157
158/// Handle subprogram
159class BTFTypeFunc : public BTFTypeBase {
160 StringRef Name;
161
162public:
163 BTFTypeFunc(StringRef FuncName, uint32_t ProtoTypeId, uint32_t Scope);
164 uint32_t getSize() override { return BTFTypeBase::getSize(); }
165 void completeType(BTFDebug &BDebug) override;
166 void emitType(MCStreamer &OS) override;
167};
168
169/// Handle variable instances
170class BTFKindVar : public BTFTypeBase {
171 StringRef Name;
172 uint32_t Info;
173
174public:
175 BTFKindVar(StringRef VarName, uint32_t TypeId, uint32_t VarInfo);
176 uint32_t getSize() override { return BTFTypeBase::getSize() + 4; }
177 void completeType(BTFDebug &BDebug) override;
178 void emitType(MCStreamer &OS) override;
179};
180
181/// Handle data sections
182class BTFKindDataSec : public BTFTypeBase {
183 AsmPrinter *Asm;
184 std::string Name;
185 std::vector<std::tuple<uint32_t, const MCSymbol *, uint32_t>> Vars;
186
187public:
188 BTFKindDataSec(AsmPrinter *AsmPrt, std::string SecName);
189 uint32_t getSize() override {
190 return BTFTypeBase::getSize() + BTF::BTFDataSecVarSize * Vars.size();
191 }
192 void addDataSecEntry(uint32_t Id, const MCSymbol *Sym, uint32_t Size) {
193 Vars.push_back(x: std::make_tuple(args&: Id, args&: Sym, args&: Size));
194 }
195 std::string getName() { return Name; }
196 void completeType(BTFDebug &BDebug) override;
197 void emitType(MCStreamer &OS) override;
198};
199
200/// Handle binary floating point type.
201class BTFTypeFloat : public BTFTypeBase {
202 StringRef Name;
203
204public:
205 BTFTypeFloat(uint32_t SizeInBits, StringRef TypeName);
206 void completeType(BTFDebug &BDebug) override;
207};
208
209/// Handle decl tags.
210class BTFTypeDeclTag : public BTFTypeBase {
211 uint32_t Info;
212 StringRef Tag;
213
214public:
215 BTFTypeDeclTag(uint32_t BaseTypeId, int ComponentId, StringRef Tag);
216 uint32_t getSize() override { return BTFTypeBase::getSize() + 4; }
217 void completeType(BTFDebug &BDebug) override;
218 void emitType(MCStreamer &OS) override;
219};
220
221/// Handle 64-bit enumerate type.
222class BTFTypeEnum64 : public BTFTypeBase {
223 const DICompositeType *ETy;
224 std::vector<struct BTF::BTFEnum64> EnumValues;
225
226public:
227 BTFTypeEnum64(const DICompositeType *ETy, uint32_t NumValues, bool IsSigned);
228 uint32_t getSize() override {
229 return BTFTypeBase::getSize() + EnumValues.size() * BTF::BTFEnum64Size;
230 }
231 void completeType(BTFDebug &BDebug) override;
232 void emitType(MCStreamer &OS) override;
233};
234
235class BTFTypeTypeTag : public BTFTypeBase {
236 const DIDerivedType *DTy;
237 StringRef Tag;
238
239public:
240 BTFTypeTypeTag(uint32_t NextTypeId, StringRef Tag);
241 BTFTypeTypeTag(const DIDerivedType *DTy, StringRef Tag);
242 void completeType(BTFDebug &BDebug) override;
243};
244
245/// String table.
246class BTFStringTable {
247 /// String table size in bytes.
248 uint32_t Size;
249 /// A mapping from string table offset to the index
250 /// of the Table. It is used to avoid putting
251 /// duplicated strings in the table.
252 std::map<uint32_t, uint32_t> OffsetToIdMap;
253 /// A vector of strings to represent the string table.
254 std::vector<std::string> Table;
255
256public:
257 BTFStringTable() : Size(0) {}
258 uint32_t getSize() { return Size; }
259 std::vector<std::string> &getTable() { return Table; }
260 /// Add a string to the string table and returns its offset
261 /// in the table.
262 uint32_t addString(StringRef S);
263};
264
265/// Represent one func and its type id.
266struct BTFFuncInfo {
267 const MCSymbol *Label; ///< Func MCSymbol
268 uint32_t TypeId; ///< Type id referring to .BTF type section
269};
270
271/// Represent one line info.
272struct BTFLineInfo {
273 MCSymbol *Label; ///< MCSymbol identifying insn for the lineinfo
274 uint32_t FileNameOff; ///< file name offset in the .BTF string table
275 uint32_t LineOff; ///< line offset in the .BTF string table
276 uint32_t LineNum; ///< the line number
277 uint32_t ColumnNum; ///< the column number
278};
279
280/// Represent one field relocation.
281struct BTFFieldReloc {
282 const MCSymbol *Label; ///< MCSymbol identifying insn for the reloc
283 uint32_t TypeID; ///< Type ID
284 uint32_t OffsetNameOff; ///< The string to traverse types
285 uint32_t RelocKind; ///< What to patch the instruction
286};
287
288/// Collect and emit BTF information.
289class BTFDebug : public DebugHandlerBase {
290 MCStreamer &OS;
291 bool SkipInstruction;
292 bool LineInfoGenerated;
293 uint32_t SecNameOff;
294 uint32_t ArrayIndexTypeId;
295 bool MapDefNotCollected;
296 BTFStringTable StringTable;
297 std::vector<std::unique_ptr<BTFTypeBase>> TypeEntries;
298 std::unordered_map<const DIType *, uint32_t> DIToIdMap;
299 std::map<uint32_t, std::vector<BTFFuncInfo>> FuncInfoTable;
300 std::map<uint32_t, std::vector<BTFLineInfo>> LineInfoTable;
301 std::map<uint32_t, std::vector<BTFFieldReloc>> FieldRelocTable;
302 StringMap<std::vector<std::string>> FileContent;
303 std::map<std::string, std::unique_ptr<BTFKindDataSec>, std::less<>>
304 DataSecEntries;
305 std::vector<BTFTypeStruct *> StructTypes;
306 std::map<const GlobalVariable *, std::pair<int64_t, uint32_t>> PatchImms;
307 std::map<const DICompositeType *,
308 std::vector<std::pair<const DIDerivedType *, BTFTypeDerived *>>>
309 FixupDerivedTypes;
310 std::set<const Function *>ProtoFunctions;
311
312 /// Add types to TypeEntries.
313 /// @{
314 /// Add types to TypeEntries and DIToIdMap.
315 uint32_t addType(std::unique_ptr<BTFTypeBase> TypeEntry, const DIType *Ty);
316 /// Add types to TypeEntries only and return type id.
317 uint32_t addType(std::unique_ptr<BTFTypeBase> TypeEntry);
318 /// @}
319
320 /// IR type visiting functions.
321 /// @{
322 void visitTypeEntry(const DIType *Ty);
323 void visitTypeEntry(const DIType *Ty, uint32_t &TypeId, bool CheckPointer,
324 bool SeenPointer);
325 void visitBasicType(const DIBasicType *BTy, uint32_t &TypeId);
326 void visitSubroutineType(
327 const DISubroutineType *STy, bool ForSubprog,
328 const std::unordered_map<uint32_t, StringRef> &FuncArgNames,
329 uint32_t &TypeId);
330 void visitFwdDeclType(const DICompositeType *CTy, bool IsUnion,
331 uint32_t &TypeId);
332 void visitCompositeType(const DICompositeType *CTy, uint32_t &TypeId);
333 void visitStructType(const DICompositeType *STy, bool IsStruct,
334 uint32_t &TypeId);
335 void visitArrayType(const DICompositeType *ATy, uint32_t &TypeId);
336 void visitEnumType(const DICompositeType *ETy, uint32_t &TypeId);
337 void visitDerivedType(const DIDerivedType *DTy, uint32_t &TypeId,
338 bool CheckPointer, bool SeenPointer);
339 void visitMapDefType(const DIType *Ty, uint32_t &TypeId);
340 /// @}
341
342 /// Check whether the type is a forward declaration candidate or not.
343 bool IsForwardDeclCandidate(const DIType *Base);
344
345 /// Get the file content for the subprogram. Certain lines of the file
346 /// later may be put into string table and referenced by line info.
347 std::string populateFileContent(const DIFile *File);
348
349 /// Construct a line info.
350 void constructLineInfo(MCSymbol *Label, const DIFile *File, uint32_t Line,
351 uint32_t Column);
352
353 /// Generate types and variables for globals.
354 void processGlobals(bool ProcessingMapDef);
355
356 /// Process global variable initializer in pursuit for function
357 /// pointers.
358 void processGlobalInitializer(const Constant *C);
359
360 /// Generate types for function prototypes.
361 void processFuncPrototypes(const Function *);
362
363 /// Generate types for decl annotations.
364 void processDeclAnnotations(DINodeArray Annotations, uint32_t BaseTypeId,
365 int ComponentId);
366
367 /// Generate types for DISubprogram and it's arguments.
368 uint32_t processDISubprogram(const DISubprogram *SP, uint32_t ProtoTypeId,
369 uint8_t Scope);
370
371 /// Generate BTF type_tag's. If BaseTypeId is nonnegative, the last
372 /// BTF type_tag in the chain points to BaseTypeId. Otherwise, it points to
373 /// the base type of DTy. Return the type id of the first BTF type_tag
374 /// in the chain. If no type_tag's are generated, a negative value
375 /// is returned.
376 int genBTFTypeTags(const DIDerivedType *DTy, int BaseTypeId);
377
378 /// Generate one field relocation record.
379 void generatePatchImmReloc(const MCSymbol *ORSym, uint32_t RootId,
380 const GlobalVariable *, bool IsAma);
381
382 /// Populating unprocessed type on demand.
383 unsigned populateType(const DIType *Ty);
384
385 /// Process global variables referenced by relocation instructions
386 /// and extern function references.
387 void processGlobalValue(const MachineOperand &MO);
388
389 /// Emit common header of .BTF and .BTF.ext sections.
390 void emitCommonHeader();
391
392 /// Emit the .BTF section.
393 void emitBTFSection();
394
395 /// Emit the .BTF.ext section.
396 void emitBTFExtSection();
397
398protected:
399 /// Gather pre-function debug information.
400 void beginFunctionImpl(const MachineFunction *MF) override;
401
402 /// Post process after all instructions in this function are processed.
403 void endFunctionImpl(const MachineFunction *MF) override;
404
405public:
406 BTFDebug(AsmPrinter *AP);
407
408 ///
409 bool InstLower(const MachineInstr *MI, MCInst &OutMI);
410
411 /// Get the special array index type id.
412 uint32_t getArrayIndexTypeId() {
413 assert(ArrayIndexTypeId);
414 return ArrayIndexTypeId;
415 }
416
417 /// Add string to the string table.
418 size_t addString(StringRef S) { return StringTable.addString(S); }
419
420 /// Get the type id for a particular DIType.
421 uint32_t getTypeId(const DIType *Ty) {
422 assert(Ty && "Invalid null Type");
423 assert(DIToIdMap.find(Ty) != DIToIdMap.end() &&
424 "DIType not added in the BDIToIdMap");
425 return DIToIdMap[Ty];
426 }
427
428 /// Process beginning of an instruction.
429 void beginInstruction(const MachineInstr *MI) override;
430
431 /// Complete all the types and emit the BTF sections.
432 void endModule() override;
433};
434
435} // end namespace llvm
436
437#endif
438