LLVM 19.0.0git
BTF.h
Go to the documentation of this file.
1//===-- BTF.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 the layout of .BTF and .BTF.ext ELF sections.
11///
12/// The binary layout for .BTF section:
13/// struct Header
14/// Type and Str subsections
15/// The Type subsection is a collection of types with type id starting with 1.
16/// The Str subsection is simply a collection of strings.
17///
18/// The binary layout for .BTF.ext section:
19/// struct ExtHeader
20/// FuncInfo, LineInfo, FieldReloc and ExternReloc subsections
21/// The FuncInfo subsection is defined as below:
22/// BTFFuncInfo Size
23/// struct SecFuncInfo for ELF section #1
24/// A number of struct BPFFuncInfo for ELF section #1
25/// struct SecFuncInfo for ELF section #2
26/// A number of struct BPFFuncInfo for ELF section #2
27/// ...
28/// The LineInfo subsection is defined as below:
29/// BPFLineInfo Size
30/// struct SecLineInfo for ELF section #1
31/// A number of struct BPFLineInfo for ELF section #1
32/// struct SecLineInfo for ELF section #2
33/// A number of struct BPFLineInfo for ELF section #2
34/// ...
35/// The FieldReloc subsection is defined as below:
36/// BPFFieldReloc Size
37/// struct SecFieldReloc for ELF section #1
38/// A number of struct BPFFieldReloc for ELF section #1
39/// struct SecFieldReloc for ELF section #2
40/// A number of struct BPFFieldReloc for ELF section #2
41/// ...
42///
43/// The section formats are also defined at
44/// https://github.com/torvalds/linux/blob/master/include/uapi/linux/btf.h
45///
46//===----------------------------------------------------------------------===//
47
48#ifndef LLVM_LIB_TARGET_BPF_BTF_H
49#define LLVM_LIB_TARGET_BPF_BTF_H
50
51#include "llvm/ADT/ArrayRef.h"
53
54namespace llvm {
55namespace BTF {
56
57enum : uint32_t { MAGIC = 0xeB9F, VERSION = 1 };
58
59/// Sizes in bytes of various things in the BTF format.
60enum {
76};
77
78/// The .BTF section header definition.
79struct Header {
80 uint16_t Magic; ///< Magic value
81 uint8_t Version; ///< Version number
82 uint8_t Flags; ///< Extra flags
83 uint32_t HdrLen; ///< Length of this header
84
85 /// All offsets are in bytes relative to the end of this header.
86 uint32_t TypeOff; ///< Offset of type section
87 uint32_t TypeLen; ///< Length of type section
88 uint32_t StrOff; ///< Offset of string section
89 uint32_t StrLen; ///< Length of string section
90};
91
92enum : uint32_t {
93 MAX_VLEN = 0xffff ///< Max # of struct/union/enum members or func args
94};
95
96enum TypeKinds : uint8_t {
97#define HANDLE_BTF_KIND(ID, NAME) BTF_KIND_##NAME = ID,
98#include "BTF.def"
99};
100
101// Constants for CommonType::Info field.
102constexpr uint32_t FWD_UNION_FLAG = 1u << 31;
103constexpr uint32_t ENUM_SIGNED_FLAG = 1u << 31;
104
105/// The BTF common type definition. Different kinds may have
106/// additional information after this structure data.
108 /// Type name offset in the string table.
110
111 /// "Info" bits arrangement:
112 /// Bits 0-15: vlen (e.g. # of struct's members)
113 /// Bits 16-23: unused
114 /// Bits 24-28: kind (e.g. int, ptr, array...etc)
115 /// Bits 29-30: unused
116 /// Bit 31: kind_flag, currently used by
117 /// struct, union and fwd
119
120 /// "Size" is used by INT, ENUM, STRUCT and UNION.
121 /// "Size" tells the size of the type it is describing.
122 ///
123 /// "Type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
124 /// FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG.
125 /// "Type" is a type_id referring to another type.
126 union {
129 };
130
131 uint32_t getKind() const { return Info >> 24 & 0x1f; }
132 uint32_t getVlen() const { return Info & 0xffff; }
133};
134
135// For some specific BTF_KIND, "struct CommonType" is immediately
136// followed by extra data.
137
138// BTF_KIND_INT is followed by a u32 and the following
139// is the 32 bits arrangement:
140// BTF_INT_ENCODING(VAL) : (((VAL) & 0x0f000000) >> 24)
141// BTF_INT_OFFSET(VAL) : (((VAL & 0x00ff0000)) >> 16)
142// BTF_INT_BITS(VAL) : ((VAL) & 0x000000ff)
143
144/// Attributes stored in the INT_ENCODING.
145enum : uint8_t {
146 INT_SIGNED = (1 << 0),
147 INT_CHAR = (1 << 1),
148 INT_BOOL = (1 << 2)
150
151/// BTF_KIND_ENUM is followed by multiple "struct BTFEnum".
152/// The exact number of btf_enum is stored in the vlen (of the
153/// info in "struct CommonType").
154struct BTFEnum {
155 uint32_t NameOff; ///< Enum name offset in the string table
156 int32_t Val; ///< Enum member value
157};
158
159/// BTF_KIND_ENUM64 is followed by multiple "struct BTFEnum64".
160/// The exact number of BTFEnum64 is stored in the vlen (of the
161/// info in "struct CommonType").
162struct BTFEnum64 {
163 uint32_t NameOff; ///< Enum name offset in the string table
164 uint32_t Val_Lo32; ///< Enum member lo32 value
165 uint32_t Val_Hi32; ///< Enum member hi32 value
166};
167
168/// BTF_KIND_ARRAY is followed by one "struct BTFArray".
169struct BTFArray {
170 uint32_t ElemType; ///< Element type
171 uint32_t IndexType; ///< Index type
172 uint32_t Nelems; ///< Number of elements for this array
173};
174
175/// BTF_KIND_STRUCT and BTF_KIND_UNION are followed
176/// by multiple "struct BTFMember". The exact number
177/// of BTFMember is stored in the vlen (of the info in
178/// "struct CommonType").
179///
180/// If the struct/union contains any bitfield member,
181/// the Offset below represents BitOffset (bits 0 - 23)
182/// and BitFieldSize(bits 24 - 31) with BitFieldSize = 0
183/// for non bitfield members. Otherwise, the Offset
184/// represents the BitOffset.
185struct BTFMember {
186 uint32_t NameOff; ///< Member name offset in the string table
187 uint32_t Type; ///< Member type
188 uint32_t Offset; ///< BitOffset or BitFieldSize+BitOffset
189};
190
191/// BTF_KIND_FUNC_PROTO are followed by multiple "struct BTFParam".
192/// The exist number of BTFParam is stored in the vlen (of the info
193/// in "struct CommonType").
194struct BTFParam {
197};
198
199/// BTF_KIND_FUNC can be global, static or extern.
200enum : uint8_t {
204};
205
206/// Variable scoping information.
207enum : uint8_t {
208 VAR_STATIC = 0, ///< Linkage: InternalLinkage
209 VAR_GLOBAL_ALLOCATED = 1, ///< Linkage: ExternalLinkage
210 VAR_GLOBAL_EXTERNAL = 2, ///< Linkage: ExternalLinkage
211};
212
213/// BTF_KIND_DATASEC are followed by multiple "struct BTFDataSecVar".
214/// The exist number of BTFDataSec is stored in the vlen (of the info
215/// in "struct CommonType").
217 uint32_t Type; ///< A BTF_KIND_VAR type
218 uint32_t Offset; ///< In-section offset
219 uint32_t Size; ///< Occupied memory size
220};
221
222/// The .BTF.ext section header definition.
223struct ExtHeader {
225 uint8_t Version;
226 uint8_t Flags;
228
229 uint32_t FuncInfoOff; ///< Offset of func info section
230 uint32_t FuncInfoLen; ///< Length of func info section
231 uint32_t LineInfoOff; ///< Offset of line info section
232 uint32_t LineInfoLen; ///< Length of line info section
233 uint32_t FieldRelocOff; ///< Offset of offset reloc section
234 uint32_t FieldRelocLen; ///< Length of offset reloc section
235};
236
237/// Specifying one function info.
239 uint32_t InsnOffset; ///< Byte offset in the section
240 uint32_t TypeId; ///< Type id referring to .BTF type section
241};
242
243/// Specifying function info's in one section.
245 uint32_t SecNameOff; ///< Section name index in the .BTF string table
246 uint32_t NumFuncInfo; ///< Number of func info's in this section
247};
248
249/// Specifying one line info.
251 uint32_t InsnOffset; ///< Byte offset in this section
252 uint32_t FileNameOff; ///< File name index in the .BTF string table
253 uint32_t LineOff; ///< Line index in the .BTF string table
254 uint32_t LineCol; ///< Line num: line_col >> 10,
255 /// col num: line_col & 0x3ff
256 uint32_t getLine() const { return LineCol >> 10; }
257 uint32_t getCol() const { return LineCol & 0x3ff; }
258};
259
260/// Specifying line info's in one section.
262 uint32_t SecNameOff; ///< Section name index in the .BTF string table
263 uint32_t NumLineInfo; ///< Number of line info's in this section
264};
265
266/// Specifying one offset relocation.
268 uint32_t InsnOffset; ///< Byte offset in this section
269 uint32_t TypeID; ///< TypeID for the relocation
270 uint32_t OffsetNameOff; ///< The string to traverse types
271 uint32_t RelocKind; ///< What to patch the instruction
272};
273
274/// Specifying offset relocation's in one section.
276 uint32_t SecNameOff; ///< Section name index in the .BTF string table
277 uint32_t NumFieldReloc; ///< Number of offset reloc's in this section
278};
279
280/// CO-RE relocation kind codes used in .BTF.ext section.
296};
297
298// Define a number of sub-types for CommonType, each with:
299// - An accessor for a relevant "tail" information (data fields that
300// follow the CommonType record in binary format).
301// - A classof() definition based on CommonType::getKind() value to
302// allow use with dyn_cast<>() function.
303
304// For CommonType sub-types that are followed by a single entry of
305// some type in the binary format.
306#define BTF_DEFINE_TAIL(Type, Accessor) \
307 const Type &Accessor() const { return *getTrailingObjects<Type>(); }
308
309// For CommonType sub-types that are followed by CommonType::getVlen()
310// number of entries of some type in the binary format.
311#define BTF_DEFINE_TAIL_ARR(Type, Accessor) \
312 ArrayRef<Type> Accessor() const { \
313 return ArrayRef<Type>(getTrailingObjects<Type>(), getVlen()); \
314 }
315
316struct ArrayType final : CommonType,
317 private TrailingObjects<ArrayType, BTFArray> {
320
321 static bool classof(const CommonType *V) {
322 return V->getKind() == BTF_KIND_ARRAY;
323 }
324};
325
326struct StructType final : CommonType,
327 private TrailingObjects<StructType, BTFMember> {
330
331 static bool classof(const CommonType *V) {
332 return V->getKind() == BTF_KIND_STRUCT || V->getKind() == BTF_KIND_UNION;
333 }
334};
335
336struct EnumType final : CommonType, private TrailingObjects<EnumType, BTFEnum> {
339
340 static bool classof(const CommonType *V) {
341 return V->getKind() == BTF_KIND_ENUM;
342 }
343};
344
345struct Enum64Type final : CommonType,
346 private TrailingObjects<Enum64Type, BTFEnum64> {
349
350 static bool classof(const CommonType *V) {
351 return V->getKind() == BTF_KIND_ENUM64;
352 }
353};
354
355#undef BTF_DEFINE_TAIL
356#undef BTF_DEFINE_TAIL_ARR
357
358} // End namespace BTF.
359} // End namespace llvm.
360
361#endif
aarch64 promote const
#define BTF_DEFINE_TAIL(Type, Accessor)
Definition: BTF.h:306
#define BTF_DEFINE_TAIL_ARR(Type, Accessor)
Definition: BTF.h:311
Mark the given Function as meaning that it cannot be changed in any way mark any values that are used as this function s parameters or by its return values(according to Uses) live as well. void DeadArgumentEliminationPass
static std::array< T, N > getArray(const MachOObjectFile &O, const void *Ptr)
This header defines support for implementing classes that have some trailing object (or arrays of obj...
See the file comment for details on the usage of the TrailingObjects type.
TypeKinds
Definition: BTF.h:96
@ MAX_VLEN
Max # of struct/union/enum members or func args.
Definition: BTF.h:93
@ VAR_GLOBAL_ALLOCATED
Linkage: ExternalLinkage.
Definition: BTF.h:209
@ VAR_STATIC
Linkage: InternalLinkage.
Definition: BTF.h:208
@ VAR_GLOBAL_EXTERNAL
Linkage: ExternalLinkage.
Definition: BTF.h:210
@ FUNC_STATIC
Definition: BTF.h:201
@ FUNC_EXTERN
Definition: BTF.h:203
@ FUNC_GLOBAL
Definition: BTF.h:202
@ BTFEnum64Size
Definition: BTF.h:66
@ BTFArraySize
Definition: BTF.h:64
@ BPFFuncInfoSize
Definition: BTF.h:73
@ BTFMemberSize
Definition: BTF.h:67
@ BTFEnumSize
Definition: BTF.h:65
@ HeaderSize
Definition: BTF.h:61
@ ExtHeaderSize
Definition: BTF.h:62
@ SecLineInfoSize
Definition: BTF.h:71
@ SecFieldRelocSize
Definition: BTF.h:72
@ BPFLineInfoSize
Definition: BTF.h:74
@ SecFuncInfoSize
Definition: BTF.h:70
@ BTFParamSize
Definition: BTF.h:68
@ BPFFieldRelocSize
Definition: BTF.h:75
@ CommonTypeSize
Definition: BTF.h:63
@ BTFDataSecVarSize
Definition: BTF.h:69
constexpr uint32_t ENUM_SIGNED_FLAG
Definition: BTF.h:103
@ VERSION
Definition: BTF.h:57
@ MAGIC
Definition: BTF.h:57
@ INT_CHAR
Definition: BTF.h:147
@ INT_SIGNED
Definition: BTF.h:146
@ INT_BOOL
Definition: BTF.h:148
constexpr uint32_t FWD_UNION_FLAG
Definition: BTF.h:102
PatchableRelocKind
CO-RE relocation kind codes used in .BTF.ext section.
Definition: BTF.h:281
@ FIELD_RSHIFT_U64
Definition: BTF.h:287
@ ENUM_VALUE
Definition: BTF.h:293
@ FIELD_SIGNEDNESS
Definition: BTF.h:285
@ FIELD_BYTE_OFFSET
Definition: BTF.h:282
@ FIELD_BYTE_SIZE
Definition: BTF.h:283
@ ENUM_VALUE_EXISTENCE
Definition: BTF.h:292
@ MAX_FIELD_RELOC_KIND
Definition: BTF.h:295
@ BTF_TYPE_ID_REMOTE
Definition: BTF.h:289
@ TYPE_EXISTENCE
Definition: BTF.h:290
@ BTF_TYPE_ID_LOCAL
Definition: BTF.h:288
@ FIELD_LSHIFT_U64
Definition: BTF.h:286
@ TYPE_MATCH
Definition: BTF.h:294
@ TYPE_SIZE
Definition: BTF.h:291
@ FIELD_EXISTENCE
Definition: BTF.h:284
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
static bool classof(const CommonType *V)
Definition: BTF.h:321
friend TrailingObjects
Definition: BTF.h:318
Specifying one offset relocation.
Definition: BTF.h:267
uint32_t InsnOffset
Byte offset in this section.
Definition: BTF.h:268
uint32_t OffsetNameOff
The string to traverse types.
Definition: BTF.h:270
uint32_t RelocKind
What to patch the instruction.
Definition: BTF.h:271
uint32_t TypeID
TypeID for the relocation.
Definition: BTF.h:269
Specifying one function info.
Definition: BTF.h:238
uint32_t InsnOffset
Byte offset in the section.
Definition: BTF.h:239
uint32_t TypeId
Type id referring to .BTF type section.
Definition: BTF.h:240
Specifying one line info.
Definition: BTF.h:250
uint32_t getLine() const
Definition: BTF.h:256
uint32_t LineCol
Line num: line_col >> 10, col num: line_col & 0x3ff.
Definition: BTF.h:254
uint32_t getCol() const
Definition: BTF.h:257
uint32_t FileNameOff
File name index in the .BTF string table.
Definition: BTF.h:252
uint32_t InsnOffset
Byte offset in this section.
Definition: BTF.h:251
uint32_t LineOff
Line index in the .BTF string table.
Definition: BTF.h:253
BTF_KIND_ARRAY is followed by one "struct BTFArray".
Definition: BTF.h:169
uint32_t Nelems
Number of elements for this array.
Definition: BTF.h:172
uint32_t IndexType
Index type.
Definition: BTF.h:171
uint32_t ElemType
Element type.
Definition: BTF.h:170
BTF_KIND_DATASEC are followed by multiple "struct BTFDataSecVar".
Definition: BTF.h:216
uint32_t Size
Occupied memory size.
Definition: BTF.h:219
uint32_t Type
A BTF_KIND_VAR type.
Definition: BTF.h:217
uint32_t Offset
In-section offset.
Definition: BTF.h:218
BTF_KIND_ENUM64 is followed by multiple "struct BTFEnum64".
Definition: BTF.h:162
uint32_t NameOff
Enum name offset in the string table.
Definition: BTF.h:163
uint32_t Val_Hi32
Enum member hi32 value.
Definition: BTF.h:165
uint32_t Val_Lo32
Enum member lo32 value.
Definition: BTF.h:164
BTF_KIND_ENUM is followed by multiple "struct BTFEnum".
Definition: BTF.h:154
int32_t Val
Enum member value.
Definition: BTF.h:156
uint32_t NameOff
Enum name offset in the string table.
Definition: BTF.h:155
BTF_KIND_STRUCT and BTF_KIND_UNION are followed by multiple "struct BTFMember".
Definition: BTF.h:185
uint32_t NameOff
Member name offset in the string table.
Definition: BTF.h:186
uint32_t Offset
BitOffset or BitFieldSize+BitOffset.
Definition: BTF.h:188
uint32_t Type
Member type.
Definition: BTF.h:187
BTF_KIND_FUNC_PROTO are followed by multiple "struct BTFParam".
Definition: BTF.h:194
uint32_t Type
Definition: BTF.h:196
uint32_t NameOff
Definition: BTF.h:195
The BTF common type definition.
Definition: BTF.h:107
uint32_t Type
Definition: BTF.h:128
uint32_t Size
Definition: BTF.h:127
uint32_t NameOff
Type name offset in the string table.
Definition: BTF.h:109
uint32_t Info
"Info" bits arrangement: Bits 0-15: vlen (e.g.
Definition: BTF.h:118
uint32_t getKind() const
Definition: BTF.h:131
uint32_t getVlen() const
Definition: BTF.h:132
static bool classof(const CommonType *V)
Definition: BTF.h:350
friend TrailingObjects
Definition: BTF.h:347
static bool classof(const CommonType *V)
Definition: BTF.h:340
friend TrailingObjects
Definition: BTF.h:337
The .BTF.ext section header definition.
Definition: BTF.h:223
uint32_t FieldRelocLen
Length of offset reloc section.
Definition: BTF.h:234
uint32_t LineInfoLen
Length of line info section.
Definition: BTF.h:232
uint8_t Flags
Definition: BTF.h:226
uint8_t Version
Definition: BTF.h:225
uint16_t Magic
Definition: BTF.h:224
uint32_t FuncInfoOff
Offset of func info section.
Definition: BTF.h:229
uint32_t FuncInfoLen
Length of func info section.
Definition: BTF.h:230
uint32_t FieldRelocOff
Offset of offset reloc section.
Definition: BTF.h:233
uint32_t LineInfoOff
Offset of line info section.
Definition: BTF.h:231
uint32_t HdrLen
Definition: BTF.h:227
The .BTF section header definition.
Definition: BTF.h:79
uint32_t TypeOff
All offsets are in bytes relative to the end of this header.
Definition: BTF.h:86
uint32_t StrOff
Offset of string section.
Definition: BTF.h:88
uint32_t TypeLen
Length of type section.
Definition: BTF.h:87
uint8_t Flags
Extra flags.
Definition: BTF.h:82
uint8_t Version
Version number.
Definition: BTF.h:81
uint32_t HdrLen
Length of this header.
Definition: BTF.h:83
uint16_t Magic
Magic value.
Definition: BTF.h:80
uint32_t StrLen
Length of string section.
Definition: BTF.h:89
Specifying offset relocation's in one section.
Definition: BTF.h:275
uint32_t NumFieldReloc
Number of offset reloc's in this section.
Definition: BTF.h:277
uint32_t SecNameOff
Section name index in the .BTF string table.
Definition: BTF.h:276
Specifying function info's in one section.
Definition: BTF.h:244
uint32_t SecNameOff
Section name index in the .BTF string table.
Definition: BTF.h:245
uint32_t NumFuncInfo
Number of func info's in this section.
Definition: BTF.h:246
Specifying line info's in one section.
Definition: BTF.h:261
uint32_t NumLineInfo
Number of line info's in this section.
Definition: BTF.h:263
uint32_t SecNameOff
Section name index in the .BTF string table.
Definition: BTF.h:262
friend TrailingObjects
Definition: BTF.h:328
static bool classof(const CommonType *V)
Definition: BTF.h:331