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f5cb0e57 | 1 | Common Trace Format (CTF) Specification (v1.8.2) |
5ba9f198 MD |
2 | |
3 | Mathieu Desnoyers, EfficiOS Inc. | |
4 | ||
339a7dde | 5 | The goal of the present document is to specify a trace format that suits the |
cc089c3a | 6 | needs of the embedded, telecom, high-performance and kernel communities. It is |
5ba9f198 | 7 | based on the Common Trace Format Requirements (v1.4) document. It is designed to |
cc089c3a | 8 | allow traces to be natively generated by the Linux kernel, Linux user-space |
6c7226e9 MD |
9 | applications written in C/C++, and hardware components. One major element of |
10 | CTF is the Trace Stream Description Language (TSDL) which flexibility | |
11 | enables description of various binary trace stream layouts. | |
cc089c3a MD |
12 | |
13 | The latest version of this document can be found at: | |
14 | ||
15 | git tree: git://git.efficios.com/ctf.git | |
16 | gitweb: http://git.efficios.com/?p=ctf.git | |
5ba9f198 MD |
17 | |
18 | A reference implementation of a library to read and write this trace format is | |
19 | being implemented within the BabelTrace project, a converter between trace | |
20 | formats. The development tree is available at: | |
21 | ||
22 | git tree: git://git.efficios.com/babeltrace.git | |
23 | gitweb: http://git.efficios.com/?p=babeltrace.git | |
24 | ||
339a7dde MD |
25 | The CE Workgroup of the Linux Foundation, Ericsson, and EfficiOS have |
26 | sponsored this work. | |
27 | ||
5ba9f198 | 28 | |
beabf088 MD |
29 | Table of Contents |
30 | ||
31 | 1. Preliminary definitions | |
32 | 2. High-level representation of a trace | |
33 | 3. Event stream | |
34 | 4. Types | |
35 | 4.1 Basic types | |
36 | 4.1.1 Type inheritance | |
37 | 4.1.2 Alignment | |
38 | 4.1.3 Byte order | |
39 | 4.1.4 Size | |
40 | 4.1.5 Integers | |
41 | 4.1.6 GNU/C bitfields | |
42 | 4.1.7 Floating point | |
43 | 4.1.8 Enumerations | |
ddd045b0 MD |
44 | 4.2 Compound types |
45 | 4.2.1 Structures | |
46 | 4.2.2 Variants (Discriminated/Tagged Unions) | |
47 | 4.2.3 Arrays | |
48 | 4.2.4 Sequences | |
49 | 4.2.5 Strings | |
beabf088 MD |
50 | 5. Event Packet Header |
51 | 5.1 Event Packet Header Description | |
52 | 5.2 Event Packet Context Description | |
53 | 6. Event Structure | |
54 | 6.1 Event Header | |
55 | 6.1.1 Type 1 - Few event IDs | |
56 | 6.1.2 Type 2 - Many event IDs | |
0b174d87 | 57 | 6.2 Stream Event Context and Event Context |
beabf088 MD |
58 | 6.3 Event Payload |
59 | 6.3.1 Padding | |
60 | 6.3.2 Alignment | |
61 | 7. Trace Stream Description Language (TSDL) | |
62 | 7.1 Meta-data | |
63 | 7.2 Declaration vs Definition | |
64 | 7.3 TSDL Scopes | |
65 | 7.3.1 Lexical Scope | |
37ab95c3 | 66 | 7.3.2 Static and Dynamic Scopes |
beabf088 | 67 | 7.4 TSDL Examples |
2fa70eba | 68 | 8. Clocks |
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69 | |
70 | ||
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71 | 1. Preliminary definitions |
72 | ||
3bf79539 MD |
73 | - Event Trace: An ordered sequence of events. |
74 | - Event Stream: An ordered sequence of events, containing a subset of the | |
75 | trace event types. | |
76 | - Event Packet: A sequence of physically contiguous events within an event | |
77 | stream. | |
5ba9f198 MD |
78 | - Event: This is the basic entry in a trace. (aka: a trace record). |
79 | - An event identifier (ID) relates to the class (a type) of event within | |
3bf79539 MD |
80 | an event stream. |
81 | e.g. event: irq_entry. | |
5ba9f198 MD |
82 | - An event (or event record) relates to a specific instance of an event |
83 | class. | |
3bf79539 MD |
84 | e.g. event: irq_entry, at time X, on CPU Y |
85 | - Source Architecture: Architecture writing the trace. | |
86 | - Reader Architecture: Architecture reading the trace. | |
5ba9f198 MD |
87 | |
88 | ||
89 | 2. High-level representation of a trace | |
90 | ||
3bf79539 MD |
91 | A trace is divided into multiple event streams. Each event stream contains a |
92 | subset of the trace event types. | |
5ba9f198 | 93 | |
3bf79539 MD |
94 | The final output of the trace, after its generation and optional transport over |
95 | the network, is expected to be either on permanent or temporary storage in a | |
96 | virtual file system. Because each event stream is appended to while a trace is | |
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97 | being recorded, each is associated with a distinct set of files for |
98 | output. Therefore, a stored trace can be represented as a directory | |
99 | containing zero, one or more files per stream. | |
5ba9f198 | 100 | |
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101 | Meta-data description associated with the trace contains information on |
102 | trace event types expressed in the Trace Stream Description Language | |
103 | (TSDL). This language describes: | |
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104 | |
105 | - Trace version. | |
106 | - Types available. | |
6672e9e1 | 107 | - Per-trace event header description. |
3bf79539 | 108 | - Per-stream event header description. |
6672e9e1 | 109 | - Per-stream event context description. |
5ba9f198 | 110 | - Per-event |
3bf79539 | 111 | - Event type to stream mapping. |
5ba9f198 MD |
112 | - Event type to name mapping. |
113 | - Event type to ID mapping. | |
6672e9e1 | 114 | - Event context description. |
5ba9f198 MD |
115 | - Event fields description. |
116 | ||
117 | ||
3bf79539 | 118 | 3. Event stream |
5ba9f198 | 119 | |
6672e9e1 | 120 | An event stream can be divided into contiguous event packets of variable |
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121 | size. An event packet can contain a certain amount of padding at the |
122 | end. The stream header is repeated at the beginning of each event | |
123 | packet. The rationale for the event stream design choices is explained | |
124 | in Appendix B. Stream Header Rationale. | |
5ba9f198 | 125 | |
3bf79539 MD |
126 | The event stream header will therefore be referred to as the "event packet |
127 | header" throughout the rest of this document. | |
5ba9f198 MD |
128 | |
129 | ||
130 | 4. Types | |
131 | ||
1fad7a85 MD |
132 | Types are organized as type classes. Each type class belong to either of two |
133 | kind of types: basic types or compound types. | |
134 | ||
5ba9f198 MD |
135 | 4.1 Basic types |
136 | ||
1fad7a85 MD |
137 | A basic type is a scalar type, as described in this section. It includes |
138 | integers, GNU/C bitfields, enumerations, and floating point values. | |
5ba9f198 MD |
139 | |
140 | 4.1.1 Type inheritance | |
141 | ||
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142 | Type specifications can be inherited to allow deriving types from a |
143 | type class. For example, see the uint32_t named type derived from the "integer" | |
144 | type class below ("Integers" section). Types have a precise binary | |
145 | representation in the trace. A type class has methods to read and write these | |
146 | types, but must be derived into a type to be usable in an event field. | |
5ba9f198 MD |
147 | |
148 | 4.1.2 Alignment | |
149 | ||
150 | We define "byte-packed" types as aligned on the byte size, namely 8-bit. | |
151 | We define "bit-packed" types as following on the next bit, as defined by the | |
370eae99 | 152 | "Integers" section. |
5ba9f198 | 153 | |
6672e9e1 | 154 | Each basic type must specify its alignment, in bits. Examples of |
ec4404a7 MD |
155 | possible alignments are: bit-packed (align = 1), byte-packed (align = |
156 | 8), or word-aligned (e.g. align = 32 or align = 64). The choice depends | |
157 | on the architecture preference and compactness vs performance trade-offs | |
158 | of the implementation. Architectures providing fast unaligned write | |
159 | byte-packed basic types to save space, aligning each type on byte | |
160 | boundaries (8-bit). Architectures with slow unaligned writes align types | |
161 | on specific alignment values. If no specific alignment is declared for a | |
162 | type, it is assumed to be bit-packed for integers with size not multiple | |
163 | of 8 bits and for gcc bitfields. All other basic types are byte-packed | |
164 | by default. It is however recommended to always specify the alignment | |
165 | explicitly. Alignment values must be power of two. Compound types are | |
166 | aligned as specified in their individual specification. | |
5ba9f198 | 167 | |
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168 | The base offset used for field alignment is the start of the packet |
169 | containing the field. For instance, a field aligned on 32-bit needs to | |
170 | be at an offset multiple of 32-bit from the start of the packet that | |
171 | contains it. | |
172 | ||
6672e9e1 | 173 | TSDL meta-data attribute representation of a specific alignment: |
5ba9f198 MD |
174 | |
175 | align = value; /* value in bits */ | |
176 | ||
177 | 4.1.3 Byte order | |
178 | ||
237324a2 MD |
179 | By default, byte order of a basic type is the byte order described in |
180 | the trace description. It can be overridden by specifying a | |
181 | "byte_order" attribute for a basic type. Typical use-case is to specify | |
182 | the network byte order (big endian: "be") to save data captured from the | |
183 | network into the trace without conversion. | |
5ba9f198 | 184 | |
6672e9e1 | 185 | TSDL meta-data representation: |
5ba9f198 MD |
186 | |
187 | byte_order = native OR network OR be OR le; /* network and be are aliases */ | |
188 | ||
237324a2 MD |
189 | The "native" keyword selects the byte order described in the trace |
190 | description. The "network" byte order is an alias for big endian. | |
191 | ||
7e58b8bf | 192 | Even though the trace description section is not per se a type, for sake |
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193 | of clarity, it should be noted that "native" and "network" byte orders |
194 | are only allowed within type declaration. The byte_order specified in | |
195 | the trace description section only accepts "be" or "le" values. | |
7e58b8bf | 196 | |
5ba9f198 MD |
197 | 4.1.4 Size |
198 | ||
199 | Type size, in bits, for integers and floats is that returned by "sizeof()" in C | |
200 | multiplied by CHAR_BIT. | |
201 | We require the size of "char" and "unsigned char" types (CHAR_BIT) to be fixed | |
202 | to 8 bits for cross-endianness compatibility. | |
203 | ||
6672e9e1 | 204 | TSDL meta-data representation: |
5ba9f198 MD |
205 | |
206 | size = value; (value is in bits) | |
207 | ||
208 | 4.1.5 Integers | |
209 | ||
6672e9e1 MD |
210 | Signed integers are represented in two-complement. Integer alignment, |
211 | size, signedness and byte ordering are defined in the TSDL meta-data. | |
212 | Integers aligned on byte size (8-bit) and with length multiple of byte | |
213 | size (8-bit) correspond to the C99 standard integers. In addition, | |
214 | integers with alignment and/or size that are _not_ a multiple of the | |
215 | byte size are permitted; these correspond to the C99 standard bitfields, | |
216 | with the added specification that the CTF integer bitfields have a fixed | |
217 | binary representation. A MIT-licensed reference implementation of the | |
218 | CTF portable bitfields is available at: | |
5ba9f198 MD |
219 | |
220 | http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h | |
221 | ||
222 | Binary representation of integers: | |
223 | ||
224 | - On little and big endian: | |
225 | - Within a byte, high bits correspond to an integer high bits, and low bits | |
226 | correspond to low bits. | |
227 | - On little endian: | |
228 | - Integer across multiple bytes are placed from the less significant to the | |
229 | most significant. | |
230 | - Consecutive integers are placed from lower bits to higher bits (even within | |
231 | a byte). | |
232 | - On big endian: | |
233 | - Integer across multiple bytes are placed from the most significant to the | |
234 | less significant. | |
235 | - Consecutive integers are placed from higher bits to lower bits (even within | |
236 | a byte). | |
237 | ||
238 | This binary representation is derived from the bitfield implementation in GCC | |
239 | for little and big endian. However, contrary to what GCC does, integers can | |
6672e9e1 | 240 | cross units boundaries (no padding is required). Padding can be explicitly |
5ba9f198 MD |
241 | added (see 4.1.6 GNU/C bitfields) to follow the GCC layout if needed. |
242 | ||
6672e9e1 | 243 | TSDL meta-data representation: |
5ba9f198 | 244 | |
80fd2569 | 245 | integer { |
5ba9f198 MD |
246 | signed = true OR false; /* default false */ |
247 | byte_order = native OR network OR be OR le; /* default native */ | |
248 | size = value; /* value in bits, no default */ | |
249 | align = value; /* value in bits */ | |
56b77c06 | 250 | /* based used for pretty-printing output, default: decimal. */ |
b46cfbf6 | 251 | base = decimal OR dec OR d OR i OR u OR 10 OR hexadecimal OR hex OR x OR X OR p OR 16 |
56b77c06 | 252 | OR octal OR oct OR o OR 8 OR binary OR b OR 2; |
13441bf5 MD |
253 | /* character encoding, default: none */ |
254 | encoding = none or UTF8 or ASCII; | |
2152348f | 255 | } |
5ba9f198 | 256 | |
80fd2569 | 257 | Example of type inheritance (creation of a uint32_t named type): |
5ba9f198 | 258 | |
359894ac | 259 | typealias integer { |
9e4e34e9 | 260 | size = 32; |
5ba9f198 MD |
261 | signed = false; |
262 | align = 32; | |
38b8da21 | 263 | } := uint32_t; |
5ba9f198 | 264 | |
80fd2569 | 265 | Definition of a named 5-bit signed bitfield: |
5ba9f198 | 266 | |
359894ac | 267 | typealias integer { |
5ba9f198 MD |
268 | size = 5; |
269 | signed = true; | |
270 | align = 1; | |
38b8da21 | 271 | } := int5_t; |
5ba9f198 | 272 | |
13441bf5 MD |
273 | The character encoding field can be used to specify that the integer |
274 | must be printed as a text character when read. e.g.: | |
275 | ||
276 | typealias integer { | |
277 | size = 8; | |
278 | align = 8; | |
279 | signed = false; | |
280 | encoding = UTF8; | |
281 | } := utf_char; | |
282 | ||
283 | ||
5ba9f198 MD |
284 | 4.1.6 GNU/C bitfields |
285 | ||
286 | The GNU/C bitfields follow closely the integer representation, with a | |
287 | particularity on alignment: if a bitfield cannot fit in the current unit, the | |
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288 | unit is padded and the bitfield starts at the following unit. The unit size is |
289 | defined by the size of the type "unit_type". | |
5ba9f198 | 290 | |
6672e9e1 | 291 | TSDL meta-data representation: |
80fd2569 | 292 | |
d674f4b8 | 293 | unit_type name:size; |
80fd2569 | 294 | |
5ba9f198 MD |
295 | As an example, the following structure declared in C compiled by GCC: |
296 | ||
297 | struct example { | |
298 | short a:12; | |
299 | short b:5; | |
300 | }; | |
301 | ||
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302 | The example structure is aligned on the largest element (short). The second |
303 | bitfield would be aligned on the next unit boundary, because it would not fit in | |
304 | the current unit. | |
5ba9f198 MD |
305 | |
306 | 4.1.7 Floating point | |
307 | ||
6672e9e1 | 308 | The floating point values byte ordering is defined in the TSDL meta-data. |
5ba9f198 MD |
309 | |
310 | Floating point values follow the IEEE 754-2008 standard interchange formats. | |
311 | Description of the floating point values include the exponent and mantissa size | |
312 | in bits. Some requirements are imposed on the floating point values: | |
313 | ||
314 | - FLT_RADIX must be 2. | |
315 | - mant_dig is the number of digits represented in the mantissa. It is specified | |
316 | by the ISO C99 standard, section 5.2.4, as FLT_MANT_DIG, DBL_MANT_DIG and | |
317 | LDBL_MANT_DIG as defined by <float.h>. | |
318 | - exp_dig is the number of digits represented in the exponent. Given that | |
319 | mant_dig is one bit more than its actual size in bits (leading 1 is not | |
320 | needed) and also given that the sign bit always takes one bit, exp_dig can be | |
321 | specified as: | |
322 | ||
323 | - sizeof(float) * CHAR_BIT - FLT_MANT_DIG | |
324 | - sizeof(double) * CHAR_BIT - DBL_MANT_DIG | |
325 | - sizeof(long double) * CHAR_BIT - LDBL_MANT_DIG | |
326 | ||
6672e9e1 | 327 | TSDL meta-data representation: |
5ba9f198 | 328 | |
80fd2569 | 329 | floating_point { |
ec4404a7 MD |
330 | exp_dig = value; |
331 | mant_dig = value; | |
332 | byte_order = native OR network OR be OR le; | |
333 | align = value; | |
2152348f | 334 | } |
5ba9f198 MD |
335 | |
336 | Example of type inheritance: | |
337 | ||
359894ac | 338 | typealias floating_point { |
5ba9f198 MD |
339 | exp_dig = 8; /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */ |
340 | mant_dig = 24; /* FLT_MANT_DIG */ | |
341 | byte_order = native; | |
ec4404a7 | 342 | align = 32; |
38b8da21 | 343 | } := float; |
5ba9f198 MD |
344 | |
345 | TODO: define NaN, +inf, -inf behavior. | |
346 | ||
ec4404a7 MD |
347 | Bit-packed, byte-packed or larger alignments can be used for floating |
348 | point values, similarly to integers. | |
349 | ||
5ba9f198 MD |
350 | 4.1.8 Enumerations |
351 | ||
352 | Enumerations are a mapping between an integer type and a table of strings. The | |
353 | numerical representation of the enumeration follows the integer type specified | |
6672e9e1 MD |
354 | by the meta-data. The enumeration mapping table is detailed in the enumeration |
355 | description within the meta-data. The mapping table maps inclusive value | |
356 | ranges (or single values) to strings. Instead of being limited to simple | |
3bf79539 | 357 | "value -> string" mappings, these enumerations map |
80fd2569 | 358 | "[ start_value ... end_value ] -> string", which map inclusive ranges of |
3bf79539 MD |
359 | values to strings. An enumeration from the C language can be represented in |
360 | this format by having the same start_value and end_value for each element, which | |
361 | is in fact a range of size 1. This single-value range is supported without | |
4767a9e7 | 362 | repeating the start and end values with the value = string declaration. |
9f04b9f6 | 363 | Enumerations need to contain at least one entry. |
80fd2569 | 364 | |
a9b83695 | 365 | enum name : integer_type { |
359894ac | 366 | somestring = start_value1 ... end_value1, |
80fd2569 MD |
367 | "other string" = start_value2 ... end_value2, |
368 | yet_another_string, /* will be assigned to end_value2 + 1 */ | |
369 | "some other string" = value, | |
370 | ... | |
371 | }; | |
372 | ||
373 | If the values are omitted, the enumeration starts at 0 and increment of 1 for | |
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374 | each entry. An entry with omitted value that follows a range entry takes |
375 | as value the end_value of the previous range + 1: | |
80fd2569 | 376 | |
a9b83695 | 377 | enum name : unsigned int { |
80fd2569 MD |
378 | ZERO, |
379 | ONE, | |
380 | TWO, | |
381 | TEN = 10, | |
382 | ELEVEN, | |
3bf79539 | 383 | }; |
5ba9f198 | 384 | |
80fd2569 | 385 | Overlapping ranges within a single enumeration are implementation defined. |
5ba9f198 | 386 | |
2152348f MD |
387 | A nameless enumeration can be declared as a field type or as part of a typedef: |
388 | ||
a9b83695 | 389 | enum : integer_type { |
2152348f MD |
390 | ... |
391 | } | |
392 | ||
c2742c56 MD |
393 | Enumerations omitting the container type ": integer_type" use the "int" |
394 | type (for compatibility with C99). The "int" type must be previously | |
395 | declared. E.g.: | |
396 | ||
82cbdb16 | 397 | typealias integer { size = 32; align = 32; signed = true; } := int; |
c2742c56 MD |
398 | |
399 | enum { | |
400 | ... | |
401 | } | |
402 | ||
1fad7a85 | 403 | |
5ba9f198 MD |
404 | 4.2 Compound types |
405 | ||
1fad7a85 MD |
406 | Compound are aggregation of type declarations. Compound types include |
407 | structures, variant, arrays, sequences, and strings. | |
408 | ||
5ba9f198 MD |
409 | 4.2.1 Structures |
410 | ||
411 | Structures are aligned on the largest alignment required by basic types | |
412 | contained within the structure. (This follows the ISO/C standard for structures) | |
413 | ||
6672e9e1 | 414 | TSDL meta-data representation of a named structure: |
5ba9f198 | 415 | |
80fd2569 MD |
416 | struct name { |
417 | field_type field_name; | |
418 | field_type field_name; | |
419 | ... | |
420 | }; | |
5ba9f198 MD |
421 | |
422 | Example: | |
423 | ||
80fd2569 MD |
424 | struct example { |
425 | integer { /* Nameless type */ | |
426 | size = 16; | |
427 | signed = true; | |
428 | align = 16; | |
429 | } first_field_name; | |
6672e9e1 | 430 | uint64_t second_field_name; /* Named type declared in the meta-data */ |
3bf79539 | 431 | }; |
5ba9f198 | 432 | |
4cac83ee MD |
433 | The fields are placed in a sequence next to each other. They each |
434 | possess a field name, which is a unique identifier within the structure. | |
435 | The identifier is not allowed to use any reserved keyword | |
436 | (see Section C.1.2). Replacing reserved keywords with | |
70375f92 | 437 | underscore-prefixed field names is recommended. Fields starting with an |
92250c71 MD |
438 | underscore should have their leading underscore removed by the CTF trace |
439 | readers. | |
5ba9f198 | 440 | |
2152348f | 441 | A nameless structure can be declared as a field type or as part of a typedef: |
80fd2569 MD |
442 | |
443 | struct { | |
444 | ... | |
2152348f | 445 | } |
80fd2569 | 446 | |
ec4404a7 MD |
447 | Alignment for a structure compound type can be forced to a minimum value |
448 | by adding an "align" specifier after the declaration of a structure | |
449 | body. This attribute is read as: align(value). The value is specified in | |
450 | bits. The structure will be aligned on the maximum value between this | |
451 | attribute and the alignment required by the basic types contained within | |
452 | the structure. e.g. | |
453 | ||
454 | struct { | |
455 | ... | |
456 | } align(32) | |
457 | ||
77a98c82 | 458 | 4.2.2 Variants (Discriminated/Tagged Unions) |
fcba70d4 | 459 | |
fdf2bb05 MD |
460 | A CTF variant is a selection between different types. A CTF variant must |
461 | always be defined within the scope of a structure or within fields | |
462 | contained within a structure (defined recursively). A "tag" enumeration | |
37ab95c3 MD |
463 | field must appear in either the same static scope, prior to the variant |
464 | field (in field declaration order), in an upper static scope , or in an | |
465 | upper dynamic scope (see Section 7.3.2). The type selection is indicated | |
466 | by the mapping from the enumeration value to the string used as variant | |
467 | type selector. The field to use as tag is specified by the "tag_field", | |
468 | specified between "< >" after the "variant" keyword for unnamed | |
469 | variants, and after "variant name" for named variants. | |
fcba70d4 | 470 | |
0bed08fc MD |
471 | The alignment of the variant is the alignment of the type as selected by |
472 | the tag value for the specific instance of the variant. The size of the | |
473 | variant is the size as selected by the tag value for the specific | |
474 | instance of the variant. | |
475 | ||
476 | The alignment of the type containing the variant is independent of the | |
477 | variant alignment. For instance, if a structure contains two fields, a | |
478 | 32-bit integer, aligned on 32 bits, and a variant, which contains two | |
479 | choices: either a 32-bit field, aligned on 32 bits, or a 64-bit field, | |
480 | aligned on 64 bits, the alignment of the outmost structure will be | |
481 | 32-bit (the alignment of its largest field, disregarding the alignment | |
482 | of the variant). The alignment of the variant will depend on the | |
483 | selector: if the variant's 32-bit field is selected, its alignment will | |
484 | be 32-bit, or 64-bit otherwise. It is important to note that variants | |
485 | are specifically tailored for compactness in a stream. Therefore, the | |
486 | relative offsets of compound type fields can vary depending on | |
487 | the offset at which the compound type starts if it contains a variant | |
488 | that itself contains a type with alignment larger than the largest field | |
489 | contained within the compound type. This is caused by the fact that the | |
490 | compound type may contain the enumeration that select the variant's | |
491 | choice, and therefore the alignment to be applied to the compound type | |
492 | cannot be determined before encountering the enumeration. | |
fcba70d4 | 493 | |
4cac83ee MD |
494 | Each variant type selector possess a field name, which is a unique |
495 | identifier within the variant. The identifier is not allowed to use any | |
496 | reserved keyword (see Section C.1.2). Replacing reserved keywords with | |
70375f92 | 497 | underscore-prefixed field names is recommended. Fields starting with an |
92250c71 MD |
498 | underscore should have their leading underscore removed by the CTF trace |
499 | readers. | |
70375f92 | 500 | |
4cac83ee | 501 | |
fcba70d4 MD |
502 | A named variant declaration followed by its definition within a structure |
503 | declaration: | |
504 | ||
505 | variant name { | |
506 | field_type sel1; | |
507 | field_type sel2; | |
508 | field_type sel3; | |
509 | ... | |
510 | }; | |
511 | ||
512 | struct { | |
a9b83695 | 513 | enum : integer_type { sel1, sel2, sel3, ... } tag_field; |
fcba70d4 MD |
514 | ... |
515 | variant name <tag_field> v; | |
516 | } | |
517 | ||
518 | An unnamed variant definition within a structure is expressed by the following | |
6672e9e1 | 519 | TSDL meta-data: |
fcba70d4 MD |
520 | |
521 | struct { | |
a9b83695 | 522 | enum : integer_type { sel1, sel2, sel3, ... } tag_field; |
fcba70d4 MD |
523 | ... |
524 | variant <tag_field> { | |
525 | field_type sel1; | |
526 | field_type sel2; | |
527 | field_type sel3; | |
528 | ... | |
529 | } v; | |
530 | } | |
531 | ||
532 | Example of a named variant within a sequence that refers to a single tag field: | |
533 | ||
534 | variant example { | |
535 | uint32_t a; | |
536 | uint64_t b; | |
537 | short c; | |
538 | }; | |
539 | ||
540 | struct { | |
a9b83695 | 541 | enum : uint2_t { a, b, c } choice; |
1ab22b2a MD |
542 | unsigned int seqlen; |
543 | variant example <choice> v[seqlen]; | |
fcba70d4 MD |
544 | } |
545 | ||
546 | Example of an unnamed variant: | |
547 | ||
548 | struct { | |
a9b83695 | 549 | enum : uint2_t { a, b, c, d } choice; |
fcba70d4 MD |
550 | /* Unrelated fields can be added between the variant and its tag */ |
551 | int32_t somevalue; | |
552 | variant <choice> { | |
553 | uint32_t a; | |
554 | uint64_t b; | |
555 | short c; | |
556 | struct { | |
557 | unsigned int field1; | |
558 | uint64_t field2; | |
559 | } d; | |
560 | } s; | |
561 | } | |
562 | ||
563 | Example of an unnamed variant within an array: | |
564 | ||
565 | struct { | |
a9b83695 | 566 | enum : uint2_t { a, b, c } choice; |
fcba70d4 MD |
567 | variant <choice> { |
568 | uint32_t a; | |
569 | uint64_t b; | |
570 | short c; | |
15850440 | 571 | } v[10]; |
fcba70d4 MD |
572 | } |
573 | ||
574 | Example of a variant type definition within a structure, where the defined type | |
575 | is then declared within an array of structures. This variant refers to a tag | |
37ab95c3 | 576 | located in an upper static scope. This example clearly shows that a variant |
fcba70d4 | 577 | type definition referring to the tag "x" uses the closest preceding field from |
37ab95c3 | 578 | the static scope of the type definition. |
fcba70d4 MD |
579 | |
580 | struct { | |
a9b83695 | 581 | enum : uint2_t { a, b, c, d } x; |
fcba70d4 MD |
582 | |
583 | typedef variant <x> { /* | |
584 | * "x" refers to the preceding "x" enumeration in the | |
37ab95c3 | 585 | * static scope of the type definition. |
fcba70d4 MD |
586 | */ |
587 | uint32_t a; | |
588 | uint64_t b; | |
589 | short c; | |
590 | } example_variant; | |
591 | ||
592 | struct { | |
a9b83695 | 593 | enum : int { x, y, z } x; /* This enumeration is not used by "v". */ |
fcba70d4 | 594 | example_variant v; /* |
a9b83695 | 595 | * "v" uses the "enum : uint2_t { a, b, c, d }" |
fcba70d4 MD |
596 | * tag. |
597 | */ | |
598 | } a[10]; | |
599 | } | |
600 | ||
601 | 4.2.3 Arrays | |
5ba9f198 | 602 | |
6672e9e1 MD |
603 | Arrays are fixed-length. Their length is declared in the type |
604 | declaration within the meta-data. They contain an array of "inner type" | |
605 | elements, which can refer to any type not containing the type of the | |
606 | array being declared (no circular dependency). The length is the number | |
607 | of elements in an array. | |
5ba9f198 | 608 | |
6672e9e1 | 609 | TSDL meta-data representation of a named array: |
80fd2569 MD |
610 | |
611 | typedef elem_type name[length]; | |
5ba9f198 | 612 | |
2152348f | 613 | A nameless array can be declared as a field type within a structure, e.g.: |
5ba9f198 | 614 | |
2152348f | 615 | uint8_t field_name[10]; |
80fd2569 | 616 | |
ec4404a7 | 617 | Arrays are always aligned on their element alignment requirement. |
5ba9f198 | 618 | |
fcba70d4 | 619 | 4.2.4 Sequences |
5ba9f198 | 620 | |
f3afd1c7 | 621 | Sequences are dynamically-sized arrays. They refer to a "length" |
37ab95c3 | 622 | unsigned integer field, which must appear in either the same static scope, |
1ab22b2a | 623 | prior to the sequence field (in field declaration order), in an upper |
37ab95c3 MD |
624 | static scope, or in an upper dynamic scope (see Section 7.3.2). This |
625 | length field represents the number of elements in the sequence. The | |
626 | sequence per se is an array of "inner type" elements. | |
5ba9f198 | 627 | |
1ab22b2a | 628 | TSDL meta-data representation for a sequence type definition: |
80fd2569 | 629 | |
1ab22b2a MD |
630 | struct { |
631 | unsigned int length_field; | |
632 | typedef elem_type typename[length_field]; | |
633 | typename seq_field_name; | |
634 | } | |
635 | ||
636 | A sequence can also be declared as a field type, e.g.: | |
80fd2569 | 637 | |
1ab22b2a MD |
638 | struct { |
639 | unsigned int length_field; | |
640 | long seq_field_name[length_field]; | |
641 | } | |
80fd2569 | 642 | |
1ab22b2a MD |
643 | Multiple sequences can refer to the same length field, and these length |
644 | fields can be in a different upper dynamic scope: | |
645 | ||
646 | e.g., assuming the stream.event.header defines: | |
647 | ||
648 | stream { | |
649 | ... | |
650 | id = 1; | |
651 | event.header := struct { | |
652 | uint16_t seq_len; | |
653 | }; | |
654 | }; | |
655 | ||
656 | event { | |
657 | ... | |
658 | stream_id = 1; | |
659 | fields := struct { | |
660 | long seq_a[stream.event.header.seq_len]; | |
661 | char seq_b[stream.event.header.seq_len]; | |
662 | }; | |
663 | }; | |
80fd2569 | 664 | |
1ab22b2a | 665 | The sequence elements follow the "array" specifications. |
5ba9f198 | 666 | |
fcba70d4 | 667 | 4.2.5 Strings |
5ba9f198 MD |
668 | |
669 | Strings are an array of bytes of variable size and are terminated by a '\0' | |
6672e9e1 MD |
670 | "NULL" character. Their encoding is described in the TSDL meta-data. In |
671 | absence of encoding attribute information, the default encoding is | |
672 | UTF-8. | |
5ba9f198 | 673 | |
6672e9e1 | 674 | TSDL meta-data representation of a named string type: |
80fd2569 | 675 | |
359894ac | 676 | typealias string { |
5ba9f198 | 677 | encoding = UTF8 OR ASCII; |
38b8da21 | 678 | } := name; |
5ba9f198 | 679 | |
80fd2569 MD |
680 | A nameless string type can be declared as a field type: |
681 | ||
682 | string field_name; /* Use default UTF8 encoding */ | |
5ba9f198 | 683 | |
ec4404a7 MD |
684 | Strings are always aligned on byte size. |
685 | ||
3bf79539 MD |
686 | 5. Event Packet Header |
687 | ||
6672e9e1 MD |
688 | The event packet header consists of two parts: the "event packet header" |
689 | is the same for all streams of a trace. The second part, the "event | |
690 | packet context", is described on a per-stream basis. Both are described | |
96bf5a3b | 691 | in the TSDL meta-data. |
3bf79539 | 692 | |
6672e9e1 | 693 | Event packet header (all fields are optional, specified by TSDL meta-data): |
3bf79539 | 694 | |
6672e9e1 MD |
695 | - Magic number (CTF magic number: 0xC1FC1FC1) specifies that this is a |
696 | CTF packet. This magic number is optional, but when present, it should | |
697 | come at the very beginning of the packet. | |
698 | - Trace UUID, used to ensure the event packet match the meta-data used. | |
699 | (note: we cannot use a meta-data checksum in every cases instead of a | |
700 | UUID because meta-data can be appended to while tracing is active) | |
701 | This field is optional. | |
702 | - Stream ID, used as reference to stream description in meta-data. | |
703 | This field is optional if there is only one stream description in the | |
704 | meta-data, but becomes required if there are more than one stream in | |
705 | the TSDL meta-data description. | |
3bf79539 | 706 | |
6672e9e1 | 707 | Event packet context (all fields are optional, specified by TSDL meta-data): |
3bf79539 | 708 | |
4dfca05b MD |
709 | - Event packet content size (in bits). |
710 | - Event packet size (in bits, includes padding). | |
cda89682 | 711 | - Event packet content checksum. Checksum excludes the event packet |
3bf79539 MD |
712 | header. |
713 | - Per-stream event packet sequence count (to deal with UDP packet loss). The | |
714 | number of significant sequence counter bits should also be present, so | |
b11853af | 715 | wrap-arounds are dealt with correctly. |
6672e9e1 | 716 | - Time-stamp at the beginning and time-stamp at the end of the event packet. |
3bf79539 MD |
717 | Both timestamps are written in the packet header, but sampled respectively |
718 | while (or before) writing the first event and while (or after) writing the | |
719 | last event in the packet. The inclusive range between these timestamps should | |
720 | include all event timestamps assigned to events contained within the packet. | |
3f584fe3 MD |
721 | The timestamp at the beginning of an event packet is guaranteed to be |
722 | below or equal the timestamp at the end of that event packet. | |
723 | The timestamp at the end of an event packet is guaranteed to be below | |
724 | or equal the timestamps at the end of any following packet within the | |
725 | same stream. See Section 8. Clocks for more detail. | |
5ba9f198 | 726 | - Events discarded count |
3bf79539 | 727 | - Snapshot of a per-stream free-running counter, counting the number of |
8f34dd4f MD |
728 | events discarded that were supposed to be written in the stream after |
729 | the last event in the event packet. | |
730 | * Note: producer-consumer buffer full condition can fill the current | |
3bf79539 | 731 | event packet with padding so we know exactly where events have been |
8f34dd4f MD |
732 | discarded. However, if the buffer full condition chooses not |
733 | to fill the current event packet with padding, all we know | |
734 | about the timestamp range in which the events have been | |
735 | discarded is that it is somewhere between the beginning and | |
736 | the end of the packet. | |
3bf79539 MD |
737 | - Lossless compression scheme used for the event packet content. Applied |
738 | directly to raw data. New types of compression can be added in following | |
739 | versions of the format. | |
5ba9f198 MD |
740 | 0: no compression scheme |
741 | 1: bzip2 | |
742 | 2: gzip | |
3bf79539 MD |
743 | 3: xz |
744 | - Cypher used for the event packet content. Applied after compression. | |
5ba9f198 MD |
745 | 0: no encryption |
746 | 1: AES | |
3bf79539 | 747 | - Checksum scheme used for the event packet content. Applied after encryption. |
5ba9f198 MD |
748 | 0: no checksum |
749 | 1: md5 | |
750 | 2: sha1 | |
751 | 3: crc32 | |
752 | ||
6672e9e1 | 753 | 5.1 Event Packet Header Description |
3bf79539 | 754 | |
fc5425db | 755 | The event packet header layout is indicated by the trace packet.header |
6672e9e1 MD |
756 | field. Here is a recommended structure type for the packet header with |
757 | the fields typically expected (although these fields are each optional): | |
fc5425db | 758 | |
80fd2569 MD |
759 | struct event_packet_header { |
760 | uint32_t magic; | |
3fde5da1 | 761 | uint8_t uuid[16]; |
3bf79539 | 762 | uint32_t stream_id; |
80fd2569 | 763 | }; |
5ba9f198 | 764 | |
fc5425db MD |
765 | trace { |
766 | ... | |
767 | packet.header := struct event_packet_header; | |
768 | }; | |
769 | ||
6672e9e1 MD |
770 | If the magic number is not present, tools such as "file" will have no |
771 | mean to discover the file type. | |
772 | ||
3fde5da1 MD |
773 | If the uuid is not present, no validation that the meta-data actually |
774 | corresponds to the stream is performed. | |
37b39e47 MD |
775 | |
776 | If the stream_id packet header field is missing, the trace can only | |
777 | contain a single stream. Its "id" field can be left out, and its events | |
778 | don't need to declare a "stream_id" field. | |
779 | ||
780 | ||
3bf79539 MD |
781 | 5.2 Event Packet Context Description |
782 | ||
783 | Event packet context example. These are declared within the stream declaration | |
6672e9e1 | 784 | in the meta-data. All these fields are optional. If the packet size field is |
6a7c61df | 785 | missing, the whole stream only contains a single packet. If the content |
f6b81726 MD |
786 | size field is missing, the packet is filled (no padding). The content |
787 | and packet sizes include all headers. | |
3bf79539 MD |
788 | |
789 | An example event packet context type: | |
790 | ||
80fd2569 | 791 | struct event_packet_context { |
3bf79539 MD |
792 | uint64_t timestamp_begin; |
793 | uint64_t timestamp_end; | |
794 | uint32_t checksum; | |
795 | uint32_t stream_packet_count; | |
796 | uint32_t events_discarded; | |
797 | uint32_t cpu_id; | |
47911ef2 MD |
798 | uint64_t/uint32_t/uint16_t content_size; |
799 | uint64_t/uint32_t/uint16_t packet_size; | |
3bf79539 MD |
800 | uint8_t compression_scheme; |
801 | uint8_t encryption_scheme; | |
3b0f8e4d | 802 | uint8_t checksum_scheme; |
3bf79539 | 803 | }; |
5ba9f198 | 804 | |
fcba70d4 | 805 | |
5ba9f198 MD |
806 | 6. Event Structure |
807 | ||
808 | The overall structure of an event is: | |
809 | ||
0b174d87 MD |
810 | 1 - Event Header (as specified by the stream meta-data) |
811 | 2 - Stream Event Context (as specified by the stream meta-data) | |
812 | 3 - Event Context (as specified by the event meta-data) | |
813 | 4 - Event Payload (as specified by the event meta-data) | |
5ba9f198 | 814 | |
fdf2bb05 | 815 | This structure defines an implicit dynamic scoping, where variants |
7d9d7e92 MD |
816 | located in inner structures (those with a higher number in the listing |
817 | above) can refer to the fields of outer structures (with lower number in | |
6c7226e9 | 818 | the listing above). See Section 7.3 TSDL Scopes for more detail. |
5ba9f198 | 819 | |
7409082d MD |
820 | The total length of an event is defined as the difference between the |
821 | end of its Event Payload and the end of the previous event's Event | |
822 | Payload. Therefore, it includes the event header alignment padding, and | |
823 | all its fields and their respective alignment padding. Events of length | |
824 | 0 are forbidden. | |
825 | ||
fdf2bb05 | 826 | 6.1 Event Header |
fcba70d4 | 827 | |
6672e9e1 | 828 | Event headers can be described within the meta-data. We hereby propose, as an |
fcba70d4 MD |
829 | example, two types of events headers. Type 1 accommodates streams with less than |
830 | 31 event IDs. Type 2 accommodates streams with 31 or more event IDs. | |
5ba9f198 | 831 | |
3bf79539 MD |
832 | One major factor can vary between streams: the number of event IDs assigned to |
833 | a stream. Luckily, this information tends to stay relatively constant (modulo | |
5ba9f198 | 834 | event registration while trace is being recorded), so we can specify different |
3bf79539 | 835 | representations for streams containing few event IDs and streams containing |
6672e9e1 MD |
836 | many event IDs, so we end up representing the event ID and time-stamp as |
837 | densely as possible in each case. | |
5ba9f198 | 838 | |
fcba70d4 MD |
839 | The header is extended in the rare occasions where the information cannot be |
840 | represented in the ranges available in the standard event header. They are also | |
3bf79539 MD |
841 | used in the rare occasions where the data required for a field could not be |
842 | collected: the flag corresponding to the missing field within the missing_fields | |
843 | array is then set to 1. | |
5ba9f198 | 844 | |
6672e9e1 MD |
845 | Types uintX_t represent an X-bit unsigned integer, as declared with |
846 | either: | |
5ba9f198 | 847 | |
82cbdb16 | 848 | typealias integer { size = X; align = X; signed = false; } := uintX_t; |
6672e9e1 MD |
849 | |
850 | or | |
851 | ||
82cbdb16 | 852 | typealias integer { size = X; align = 1; signed = false; } := uintX_t; |
5ba9f198 | 853 | |
2a0bae9e MD |
854 | For more information about timestamp fields, see Section 8. Clocks. |
855 | ||
fdf2bb05 | 856 | 6.1.1 Type 1 - Few event IDs |
5ba9f198 MD |
857 | |
858 | - Aligned on 32-bit (or 8-bit if byte-packed, depending on the architecture | |
859 | preference). | |
5ba9f198 | 860 | - Native architecture byte ordering. |
fcba70d4 MD |
861 | - For "compact" selection |
862 | - Fixed size: 32 bits. | |
863 | - For "extended" selection | |
864 | - Size depends on the architecture and variant alignment. | |
5ba9f198 | 865 | |
80fd2569 | 866 | struct event_header_1 { |
fcba70d4 MD |
867 | /* |
868 | * id: range: 0 - 30. | |
869 | * id 31 is reserved to indicate an extended header. | |
870 | */ | |
a9b83695 | 871 | enum : uint5_t { compact = 0 ... 30, extended = 31 } id; |
fcba70d4 MD |
872 | variant <id> { |
873 | struct { | |
874 | uint27_t timestamp; | |
875 | } compact; | |
876 | struct { | |
877 | uint32_t id; /* 32-bit event IDs */ | |
878 | uint64_t timestamp; /* 64-bit timestamps */ | |
879 | } extended; | |
880 | } v; | |
cb108fea | 881 | } align(32); /* or align(8) */ |
5ba9f198 | 882 | |
5ba9f198 | 883 | |
fdf2bb05 | 884 | 6.1.2 Type 2 - Many event IDs |
5ba9f198 | 885 | |
fcba70d4 | 886 | - Aligned on 16-bit (or 8-bit if byte-packed, depending on the architecture |
5ba9f198 | 887 | preference). |
5ba9f198 | 888 | - Native architecture byte ordering. |
fcba70d4 MD |
889 | - For "compact" selection |
890 | - Size depends on the architecture and variant alignment. | |
891 | - For "extended" selection | |
892 | - Size depends on the architecture and variant alignment. | |
5ba9f198 | 893 | |
80fd2569 | 894 | struct event_header_2 { |
fcba70d4 MD |
895 | /* |
896 | * id: range: 0 - 65534. | |
897 | * id 65535 is reserved to indicate an extended header. | |
898 | */ | |
a9b83695 | 899 | enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id; |
fcba70d4 MD |
900 | variant <id> { |
901 | struct { | |
902 | uint32_t timestamp; | |
903 | } compact; | |
904 | struct { | |
905 | uint32_t id; /* 32-bit event IDs */ | |
906 | uint64_t timestamp; /* 64-bit timestamps */ | |
907 | } extended; | |
908 | } v; | |
cb108fea | 909 | } align(16); /* or align(8) */ |
5ba9f198 | 910 | |
5ba9f198 | 911 | |
0b174d87 | 912 | 6.2 Stream Event Context and Event Context |
5ba9f198 | 913 | |
6672e9e1 MD |
914 | The event context contains information relative to the current event. |
915 | The choice and meaning of this information is specified by the TSDL | |
916 | stream and event meta-data descriptions. The stream context is applied | |
917 | to all events within the stream. The stream context structure follows | |
918 | the event header. The event context is applied to specific events. Its | |
919 | structure follows the stream context structure. | |
5ba9f198 | 920 | |
fcba70d4 MD |
921 | An example of stream-level event context is to save the event payload size with |
922 | each event, or to save the current PID with each event. These are declared | |
6672e9e1 | 923 | within the stream declaration within the meta-data: |
5ba9f198 | 924 | |
fcba70d4 MD |
925 | stream { |
926 | ... | |
6672e9e1 | 927 | event.context := struct { |
80fd2569 MD |
928 | uint pid; |
929 | uint16_t payload_size; | |
6672e9e1 | 930 | }; |
fcba70d4 MD |
931 | }; |
932 | ||
933 | An example of event-specific event context is to declare a bitmap of missing | |
934 | fields, only appended after the stream event context if the extended event | |
935 | header is selected. NR_FIELDS is the number of fields within the event (a | |
936 | numeric value). | |
5ba9f198 | 937 | |
fcba70d4 MD |
938 | event { |
939 | context = struct { | |
940 | variant <id> { | |
941 | struct { } compact; | |
942 | struct { | |
943 | uint1_t missing_fields[NR_FIELDS]; /* missing event fields bitmap */ | |
944 | } extended; | |
945 | } v; | |
946 | }; | |
947 | ... | |
948 | } | |
5ba9f198 MD |
949 | |
950 | 6.3 Event Payload | |
951 | ||
952 | An event payload contains fields specific to a given event type. The fields | |
6672e9e1 | 953 | belonging to an event type are described in the event-specific meta-data |
5ba9f198 MD |
954 | within a structure type. |
955 | ||
956 | 6.3.1 Padding | |
957 | ||
958 | No padding at the end of the event payload. This differs from the ISO/C standard | |
959 | for structures, but follows the CTF standard for structures. In a trace, even | |
960 | though it makes sense to align the beginning of a structure, it really makes no | |
961 | sense to add padding at the end of the structure, because structures are usually | |
962 | not followed by a structure of the same type. | |
963 | ||
964 | This trick can be done by adding a zero-length "end" field at the end of the C | |
965 | structures, and by using the offset of this field rather than using sizeof() | |
3bf79539 | 966 | when calculating the size of a structure (see Appendix "A. Helper macros"). |
5ba9f198 MD |
967 | |
968 | 6.3.2 Alignment | |
969 | ||
970 | The event payload is aligned on the largest alignment required by types | |
971 | contained within the payload. (This follows the ISO/C standard for structures) | |
972 | ||
973 | ||
6c7226e9 MD |
974 | 7. Trace Stream Description Language (TSDL) |
975 | ||
976 | The Trace Stream Description Language (TSDL) allows expression of the | |
977 | binary trace streams layout in a C99-like Domain Specific Language | |
978 | (DSL). | |
979 | ||
980 | ||
6672e9e1 | 981 | 7.1 Meta-data |
6c7226e9 MD |
982 | |
983 | The trace stream layout description is located in the trace meta-data. | |
984 | The meta-data is itself located in a stream identified by its name: | |
985 | "metadata". | |
5ba9f198 | 986 | |
6672e9e1 MD |
987 | The meta-data description can be expressed in two different formats: |
988 | text-only and packet-based. The text-only description facilitates | |
989 | generation of meta-data and provides a convenient way to enter the | |
990 | meta-data information by hand. The packet-based meta-data provides the | |
991 | CTF stream packet facilities (checksumming, compression, encryption, | |
992 | network-readiness) for meta-data stream generated and transported by a | |
993 | tracer. | |
994 | ||
1b4d35eb MD |
995 | The text-only meta-data file is a plain-text TSDL description. This file |
996 | must begin with the following characters to identify the file as a CTF | |
9486a18c | 997 | TSDL text-based metadata file (without the double-quotes) : |
1b4d35eb | 998 | |
ec2b4db8 | 999 | "/* CTF" |
1b4d35eb | 1000 | |
ec2b4db8 MD |
1001 | It must be followed by a space, and the version of the specification |
1002 | followed by the CTF trace, e.g.: | |
1003 | ||
1004 | " 1.8" | |
1005 | ||
1006 | These characters allow automated discovery of file type and CTF | |
1007 | specification version. They are interpreted as a the beginning of a | |
1008 | comment by the TSDL metadata parser. The comment can be continued to | |
1009 | contain extra commented characters before it is closed. | |
6672e9e1 MD |
1010 | |
1011 | The packet-based meta-data is made of "meta-data packets", which each | |
1012 | start with a meta-data packet header. The packet-based meta-data | |
1013 | description is detected by reading the magic number "0x75D11D57" at the | |
1014 | beginning of the file. This magic number is also used to detect the | |
1015 | endianness of the architecture by trying to read the CTF magic number | |
1016 | and its counterpart in reversed endianness. The events within the | |
1017 | meta-data stream have no event header nor event context. Each event only | |
46400bde MD |
1018 | contains a special "sequence" payload, which is a sequence of bits which |
1019 | length is implicitly calculated by using the | |
1020 | "trace.packet.header.content_size" field, minus the packet header size. | |
1021 | The formatting of this sequence of bits is a plain-text representation | |
1022 | of the TSDL description. Each meta-data packet start with a special | |
1023 | packet header, specific to the meta-data stream, which contains, | |
1024 | exactly: | |
6672e9e1 MD |
1025 | |
1026 | struct metadata_packet_header { | |
2daeaa3a | 1027 | uint32_t magic; /* 0x75D11D57 */ |
3fde5da1 | 1028 | uint8_t uuid[16]; /* Unique Universal Identifier */ |
6672e9e1 MD |
1029 | uint32_t checksum; /* 0 if unused */ |
1030 | uint32_t content_size; /* in bits */ | |
1031 | uint32_t packet_size; /* in bits */ | |
1032 | uint8_t compression_scheme; /* 0 if unused */ | |
1033 | uint8_t encryption_scheme; /* 0 if unused */ | |
1034 | uint8_t checksum_scheme; /* 0 if unused */ | |
ec2b4db8 MD |
1035 | uint8_t major; /* CTF spec version major number */ |
1036 | uint8_t minor; /* CTF spec version minor number */ | |
6672e9e1 MD |
1037 | }; |
1038 | ||
1039 | The packet-based meta-data can be converted to a text-only meta-data by | |
3568031f | 1040 | concatenating all the strings it contains. |
4fafe1ad | 1041 | |
6672e9e1 MD |
1042 | In the textual representation of the meta-data, the text contained |
1043 | within "/*" and "*/", as well as within "//" and end of line, are | |
1044 | treated as comments. Boolean values can be represented as true, TRUE, | |
1045 | or 1 for true, and false, FALSE, or 0 for false. Within the string-based | |
1046 | meta-data description, the trace UUID is represented as a string of | |
1047 | hexadecimal digits and dashes "-". In the event packet header, the trace | |
1048 | UUID is represented as an array of bytes. | |
fcba70d4 | 1049 | |
fdf2bb05 | 1050 | |
6c7226e9 | 1051 | 7.2 Declaration vs Definition |
fdf2bb05 MD |
1052 | |
1053 | A declaration associates a layout to a type, without specifying where | |
1054 | this type is located in the event structure hierarchy (see Section 6). | |
1055 | This therefore includes typedef, typealias, as well as all type | |
1056 | specifiers. In certain circumstances (typedef, structure field and | |
1057 | variant field), a declaration is followed by a declarator, which specify | |
1058 | the newly defined type name (for typedef), or the field name (for | |
1059 | declarations located within structure and variants). Array and sequence, | |
1060 | declared with square brackets ("[" "]"), are part of the declarator, | |
a9b83695 | 1061 | similarly to C99. The enumeration base type is specified by |
6c7226e9 | 1062 | ": enum_base", which is part of the type specifier. The variant tag |
a9b83695 | 1063 | name, specified between "<" ">", is also part of the type specifier. |
fdf2bb05 MD |
1064 | |
1065 | A definition associates a type to a location in the event structure | |
b9606a77 MD |
1066 | hierarchy (see Section 6). This association is denoted by ":=", as shown |
1067 | in Section 7.3. | |
fdf2bb05 MD |
1068 | |
1069 | ||
6c7226e9 | 1070 | 7.3 TSDL Scopes |
fdf2bb05 | 1071 | |
37ab95c3 MD |
1072 | TSDL uses three different types of scoping: a lexical scope is used for |
1073 | declarations and type definitions, and static and dynamic scopes are | |
1074 | used for variants references to tag fields (with relative and absolute | |
1075 | path lookups) and for sequence references to length fields. | |
fdf2bb05 | 1076 | |
6c7226e9 | 1077 | 7.3.1 Lexical Scope |
fdf2bb05 | 1078 | |
570ecabe MD |
1079 | Each of "trace", "env", "stream", "event", "struct" and "variant" have |
1080 | their own nestable declaration scope, within which types can be declared | |
1081 | using "typedef" and "typealias". A root declaration scope also contains | |
1082 | all declarations located outside of any of the aforementioned | |
1083 | declarations. An inner declaration scope can refer to type declared | |
1084 | within its container lexical scope prior to the inner declaration scope. | |
1085 | Redefinition of a typedef or typealias is not valid, although hiding an | |
1086 | upper scope typedef or typealias is allowed within a sub-scope. | |
fdf2bb05 | 1087 | |
37ab95c3 | 1088 | 7.3.2 Static and Dynamic Scopes |
fdf2bb05 | 1089 | |
37ab95c3 MD |
1090 | A local static scope consists in the scope generated by the declaration |
1091 | of fields within a compound type. A static scope is a local static scope | |
1092 | augmented with the nested sub-static-scopes it contains. | |
1093 | ||
1094 | A dynamic scope consists in the static scope augmented with the | |
7d9d7e92 | 1095 | implicit event structure definition hierarchy presented at Section 6. |
fdf2bb05 | 1096 | |
37ab95c3 MD |
1097 | Multiple declarations of the same field name within a local static scope |
1098 | is not valid. It is however valid to re-use the same field name in | |
1099 | different local scopes. | |
1100 | ||
1101 | Nested static and dynamic scopes form lookup paths. These are used for | |
1102 | variant tag and sequence length references. They are used at the variant | |
1103 | and sequence definition site to look up the location of the tag field | |
1104 | associated with a variant, and to lookup up the location of the length | |
1105 | field associated with a sequence. | |
1106 | ||
1107 | Variants and sequences can refer to a tag field either using a relative | |
4cac83ee MD |
1108 | path or an absolute path. The relative path is relative to the scope in |
1109 | which the variant or sequence performing the lookup is located. | |
37ab95c3 MD |
1110 | Relative paths are only allowed to lookup within the same static scope, |
1111 | which includes its nested static scopes. Lookups targeting parent static | |
1112 | scopes need to be performed with an absolute path. | |
1113 | ||
1114 | Absolute path lookups use the full path including the dynamic scope | |
1115 | followed by a "." and then the static scope. Therefore, variants (or | |
1116 | sequences) in lower levels in the dynamic scope (e.g. event context) can | |
1117 | refer to a tag (or length) field located in upper levels (e.g. in the | |
1118 | event header) by specifying, in this case, the associated tag with | |
1119 | <stream.event.header.field_name>. This allows, for instance, the event | |
1120 | context to define a variant referring to the "id" field of the event | |
1121 | header as selector. | |
1122 | ||
284724ae | 1123 | The dynamic scope prefixes are thus: |
fdf2bb05 | 1124 | |
570ecabe | 1125 | - Trace Environment: <env. >, |
e0d9e2c7 | 1126 | - Trace Packet Header: <trace.packet.header. >, |
7d9d7e92 MD |
1127 | - Stream Packet Context: <stream.packet.context. >, |
1128 | - Event Header: <stream.event.header. >, | |
1129 | - Stream Event Context: <stream.event.context. >, | |
1130 | - Event Context: <event.context. >, | |
1131 | - Event Payload: <event.fields. >. | |
fdf2bb05 | 1132 | |
37ab95c3 MD |
1133 | |
1134 | The target dynamic scope must be specified explicitly when referring to | |
4cac83ee MD |
1135 | a field outside of the static scope (absolute scope reference). No |
1136 | conflict can occur between relative and dynamic paths, because the | |
1137 | keywords "trace", "stream", and "event" are reserved, and thus | |
1138 | not permitted as field names. It is recommended that field names | |
1139 | clashing with CTF and C99 reserved keywords use an underscore prefix to | |
1140 | eliminate the risk of generating a description containing an invalid | |
70375f92 | 1141 | field name. Consequently, fields starting with an underscore should have |
92250c71 | 1142 | their leading underscore removed by the CTF trace readers. |
70375f92 | 1143 | |
fdf2bb05 | 1144 | |
457d8b0a MD |
1145 | The information available in the dynamic scopes can be thought of as the |
1146 | current tracing context. At trace production, information about the | |
1147 | current context is saved into the specified scope field levels. At trace | |
1148 | consumption, for each event, the current trace context is therefore | |
1149 | readable by accessing the upper dynamic scopes. | |
1150 | ||
fdf2bb05 | 1151 | |
6c7226e9 | 1152 | 7.4 TSDL Examples |
d285084f | 1153 | |
6672e9e1 | 1154 | The grammar representing the TSDL meta-data is presented in Appendix C. |
7df6b93a | 1155 | TSDL Grammar. This section presents a rather lighter reading that |
6672e9e1 | 1156 | consists in examples of TSDL meta-data, with template values. |
969f30c0 | 1157 | |
350bb633 MD |
1158 | The stream "id" can be left out if there is only one stream in the |
1159 | trace. The event "id" field can be left out if there is only one event | |
1160 | in a stream. | |
1161 | ||
5ba9f198 | 1162 | trace { |
1e9de2d1 MD |
1163 | major = value; /* CTF spec version major number */ |
1164 | minor = value; /* CTF spec version minor number */ | |
fdf2bb05 | 1165 | uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"; /* Trace UUID */ |
58997e9e | 1166 | byte_order = be OR le; /* Endianness (required) */ |
fc5425db MD |
1167 | packet.header := struct { |
1168 | uint32_t magic; | |
3fde5da1 | 1169 | uint8_t uuid[16]; |
fc5425db MD |
1170 | uint32_t stream_id; |
1171 | }; | |
3bf79539 | 1172 | }; |
5ba9f198 | 1173 | |
570ecabe MD |
1174 | /* |
1175 | * The "env" (environment) scope contains assignment expressions. The | |
1176 | * field names and content are implementation-defined. | |
1177 | */ | |
1178 | env { | |
1179 | pid = value; /* example */ | |
1180 | proc_name = "name"; /* example */ | |
1181 | ... | |
1182 | }; | |
1183 | ||
3bf79539 MD |
1184 | stream { |
1185 | id = stream_id; | |
fdf2bb05 | 1186 | /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */ |
4fa992a5 MD |
1187 | event.header := event_header_1 OR event_header_2; |
1188 | event.context := struct { | |
77a98c82 | 1189 | ... |
3bf79539 | 1190 | }; |
4fa992a5 | 1191 | packet.context := struct { |
77a98c82 | 1192 | ... |
3bf79539 MD |
1193 | }; |
1194 | }; | |
5ba9f198 MD |
1195 | |
1196 | event { | |
980015f9 | 1197 | name = "event_name"; |
3bf79539 | 1198 | id = value; /* Numeric identifier within the stream */ |
67f02e24 | 1199 | stream_id = stream_id; |
dc56f167 | 1200 | loglevel = value; |
8e9060f2 | 1201 | model.emf.uri = "string"; |
4fa992a5 | 1202 | context := struct { |
fcba70d4 MD |
1203 | ... |
1204 | }; | |
4fa992a5 | 1205 | fields := struct { |
80fd2569 MD |
1206 | ... |
1207 | }; | |
3bf79539 | 1208 | }; |
5ba9f198 | 1209 | |
555f54e6 MD |
1210 | callsite { |
1211 | name = "event_name"; | |
1212 | func = "func_name"; | |
1213 | file = "myfile.c"; | |
1214 | line = 39; | |
5a6b4ee1 | 1215 | ip = 0x40096c; |
555f54e6 MD |
1216 | }; |
1217 | ||
5ba9f198 MD |
1218 | /* More detail on types in section 4. Types */ |
1219 | ||
3d13ef1a MD |
1220 | /* |
1221 | * Named types: | |
1222 | * | |
4fa992a5 | 1223 | * Type declarations behave similarly to the C standard. |
3d13ef1a MD |
1224 | */ |
1225 | ||
80af8ac6 | 1226 | typedef aliased_type_specifiers new_type_declarators; |
2152348f | 1227 | |
3d13ef1a | 1228 | /* e.g.: typedef struct example new_type_name[10]; */ |
80fd2569 | 1229 | |
4fa992a5 MD |
1230 | /* |
1231 | * typealias | |
1232 | * | |
1233 | * The "typealias" declaration can be used to give a name (including | |
80af8ac6 MD |
1234 | * pointer declarator specifier) to a type. It should also be used to |
1235 | * map basic C types (float, int, unsigned long, ...) to a CTF type. | |
1236 | * Typealias is a superset of "typedef": it also allows assignment of a | |
38b8da21 | 1237 | * simple variable identifier to a type. |
4fa992a5 MD |
1238 | */ |
1239 | ||
1240 | typealias type_class { | |
80fd2569 | 1241 | ... |
38b8da21 | 1242 | } := type_specifiers type_declarator; |
2152348f | 1243 | |
3d13ef1a MD |
1244 | /* |
1245 | * e.g.: | |
4fa992a5 | 1246 | * typealias integer { |
3d13ef1a MD |
1247 | * size = 32; |
1248 | * align = 32; | |
1249 | * signed = false; | |
38b8da21 | 1250 | * } := struct page *; |
359894ac MD |
1251 | * |
1252 | * typealias integer { | |
1253 | * size = 32; | |
1254 | * align = 32; | |
1255 | * signed = true; | |
38b8da21 | 1256 | * } := int; |
3d13ef1a | 1257 | */ |
80fd2569 MD |
1258 | |
1259 | struct name { | |
3bf79539 MD |
1260 | ... |
1261 | }; | |
5ba9f198 | 1262 | |
fcba70d4 MD |
1263 | variant name { |
1264 | ... | |
1265 | }; | |
1266 | ||
a9b83695 | 1267 | enum name : integer_type { |
3bf79539 MD |
1268 | ... |
1269 | }; | |
1270 | ||
2152348f | 1271 | |
4fa992a5 MD |
1272 | /* |
1273 | * Unnamed types, contained within compound type fields, typedef or typealias. | |
1274 | */ | |
2152348f | 1275 | |
80fd2569 MD |
1276 | struct { |
1277 | ... | |
2152348f | 1278 | } |
5ba9f198 | 1279 | |
ec4404a7 MD |
1280 | struct { |
1281 | ... | |
1282 | } align(value) | |
1283 | ||
fcba70d4 MD |
1284 | variant { |
1285 | ... | |
1286 | } | |
1287 | ||
a9b83695 | 1288 | enum : integer_type { |
80fd2569 | 1289 | ... |
2152348f MD |
1290 | } |
1291 | ||
1292 | typedef type new_type[length]; | |
3bf79539 | 1293 | |
2152348f MD |
1294 | struct { |
1295 | type field_name[length]; | |
1296 | } | |
1297 | ||
1298 | typedef type new_type[length_type]; | |
1299 | ||
1300 | struct { | |
1301 | type field_name[length_type]; | |
1302 | } | |
1303 | ||
1304 | integer { | |
80fd2569 | 1305 | ... |
2152348f | 1306 | } |
3bf79539 | 1307 | |
2152348f | 1308 | floating_point { |
80fd2569 | 1309 | ... |
2152348f MD |
1310 | } |
1311 | ||
1312 | struct { | |
1313 | integer_type field_name:size; /* GNU/C bitfield */ | |
1314 | } | |
1315 | ||
1316 | struct { | |
1317 | string field_name; | |
1318 | } | |
3bf79539 | 1319 | |
fcba70d4 | 1320 | |
2fa70eba MD |
1321 | 8. Clocks |
1322 | ||
1323 | Clock metadata allows to describe the clock topology of the system, as | |
1324 | well as to detail each clock parameter. In absence of clock description, | |
1325 | it is assumed that all fields named "timestamp" use the same clock | |
aed18b5e | 1326 | source, which increments once per nanosecond. |
2fa70eba MD |
1327 | |
1328 | Describing a clock and how it is used by streams is threefold: first, | |
1329 | the clock and clock topology should be described in a "clock" | |
1330 | description block, e.g.: | |
1331 | ||
d803bfcb | 1332 | clock { |
58262d97 | 1333 | name = cycle_counter_sync; |
2fa70eba | 1334 | uuid = "62189bee-96dc-11e0-91a8-cfa3d89f3923"; |
58262d97 | 1335 | description = "Cycle counter synchronized across CPUs"; |
2fa70eba MD |
1336 | freq = 1000000000; /* frequency, in Hz */ |
1337 | /* precision in seconds is: 1000 * (1/freq) */ | |
1338 | precision = 1000; | |
a40cccda MD |
1339 | /* |
1340 | * clock value offset from Epoch is: | |
1341 | * offset_s + (offset * (1/freq)) | |
1342 | */ | |
1343 | offset_s = 1326476837; | |
1344 | offset = 897235420; | |
ce0fadbd | 1345 | absolute = FALSE; |
2fa70eba MD |
1346 | }; |
1347 | ||
d803bfcb MD |
1348 | The mandatory "name" field specifies the name of the clock identifier, |
1349 | which can later be used as a reference. The optional field "uuid" is the | |
1350 | unique identifier of the clock. It can be used to correlate different | |
1351 | traces that use the same clock. An optional textual description string | |
1352 | can be added with the "description" field. The "freq" field is the | |
1353 | initial frequency of the clock, in Hz. If the "freq" field is not | |
1354 | present, the frequency is assumed to be 1000000000 (providing clock | |
1355 | increment of 1 ns). The optional "precision" field details the | |
a40cccda MD |
1356 | uncertainty on the clock measurements, in (1/freq) units. The "offset_s" |
1357 | and "offset" fields indicate the offset from POSIX.1 Epoch, 1970-01-01 | |
1358 | 00:00:00 +0000 (UTC), to the zero of value of the clock. The "offset_s" | |
1359 | field is in seconds. The "offset" field is in (1/freq) units. If any of | |
1360 | the "offset_s" or "offset" field is not present, it is assigned the 0 | |
ce0fadbd MD |
1361 | value. The field "absolute" is TRUE if the clock is a global reference |
1362 | across different clock uuid (e.g. NTP time). Otherwise, "absolute" is | |
1363 | FALSE, and the clock can be considered as synchronized only with other | |
1364 | clocks that have the same uuid. | |
1365 | ||
2fa70eba MD |
1366 | |
1367 | Secondly, a reference to this clock should be added within an integer | |
1368 | type: | |
1369 | ||
1370 | typealias integer { | |
1371 | size = 64; align = 1; signed = false; | |
58262d97 | 1372 | map = clock.cycle_counter_sync.value; |
2fa70eba MD |
1373 | } := uint64_ccnt_t; |
1374 | ||
1375 | Thirdly, stream declarations can reference the clock they use as a | |
1376 | time-stamp source: | |
1377 | ||
1378 | struct packet_context { | |
1379 | uint64_ccnt_t ccnt_begin; | |
1380 | uint64_ccnt_t ccnt_end; | |
1381 | /* ... */ | |
1382 | }; | |
1383 | ||
1384 | stream { | |
1385 | /* ... */ | |
1386 | event.header := struct { | |
1387 | uint64_ccnt_t timestamp; | |
1388 | /* ... */ | |
1389 | } | |
1390 | packet.context := struct packet_context; | |
1391 | }; | |
1392 | ||
1393 | For a N-bit integer type referring to a clock, if the integer overflows | |
2a0bae9e MD |
1394 | compared to the N low order bits of the clock prior value found in the |
1395 | same stream, then it is assumed that one, and only one, overflow | |
1396 | occurred. It is therefore important that events encoding time on a small | |
1397 | number of bits happen frequently enough to detect when more than one | |
1398 | N-bit overflow occurs. | |
2fa70eba MD |
1399 | |
1400 | In a packet context, clock field names ending with "_begin" and "_end" | |
1401 | have a special meaning: this refers to the time-stamps at, respectively, | |
1402 | the beginning and the end of each packet. | |
1403 | ||
1404 | ||
3bf79539 | 1405 | A. Helper macros |
5ba9f198 MD |
1406 | |
1407 | The two following macros keep track of the size of a GNU/C structure without | |
1408 | padding at the end by placing HEADER_END as the last field. A one byte end field | |
1409 | is used for C90 compatibility (C99 flexible arrays could be used here). Note | |
1410 | that this does not affect the effective structure size, which should always be | |
1411 | calculated with the header_sizeof() helper. | |
1412 | ||
1413 | #define HEADER_END char end_field | |
1414 | #define header_sizeof(type) offsetof(typeof(type), end_field) | |
3bf79539 MD |
1415 | |
1416 | ||
1417 | B. Stream Header Rationale | |
1418 | ||
1419 | An event stream is divided in contiguous event packets of variable size. These | |
1420 | subdivisions allow the trace analyzer to perform a fast binary search by time | |
1421 | within the stream (typically requiring to index only the event packet headers) | |
1422 | without reading the whole stream. These subdivisions have a variable size to | |
1423 | eliminate the need to transfer the event packet padding when partially filled | |
1424 | event packets must be sent when streaming a trace for live viewing/analysis. | |
1425 | An event packet can contain a certain amount of padding at the end. Dividing | |
1426 | streams into event packets is also useful for network streaming over UDP and | |
1427 | flight recorder mode tracing (a whole event packet can be swapped out of the | |
1428 | buffer atomically for reading). | |
1429 | ||
1430 | The stream header is repeated at the beginning of each event packet to allow | |
1431 | flexibility in terms of: | |
1432 | ||
1433 | - streaming support, | |
1434 | - allowing arbitrary buffers to be discarded without making the trace | |
1435 | unreadable, | |
1436 | - allow UDP packet loss handling by either dealing with missing event packet | |
1437 | or asking for re-transmission. | |
1438 | - transparently support flight recorder mode, | |
1439 | - transparently support crash dump. | |
1440 | ||
6c7226e9 MD |
1441 | |
1442 | C. TSDL Grammar | |
fcba70d4 | 1443 | |
4fa992a5 | 1444 | /* |
6c7226e9 | 1445 | * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar. |
4fa992a5 MD |
1446 | * |
1447 | * Inspired from the C99 grammar: | |
1448 | * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A) | |
6c7226e9 MD |
1449 | * and c++1x grammar (draft) |
1450 | * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A) | |
4fa992a5 MD |
1451 | * |
1452 | * Specialized for CTF needs by including only constant and declarations from | |
1453 | * C99 (excluding function declarations), and by adding support for variants, | |
6c7226e9 MD |
1454 | * sequences and CTF-specific specifiers. Enumeration container types |
1455 | * semantic is inspired from c++1x enum-base. | |
4fa992a5 MD |
1456 | */ |
1457 | ||
1458 | 1) Lexical grammar | |
1459 | ||
1460 | 1.1) Lexical elements | |
1461 | ||
1462 | token: | |
1463 | keyword | |
1464 | identifier | |
1465 | constant | |
1466 | string-literal | |
1467 | punctuator | |
1468 | ||
1469 | 1.2) Keywords | |
1470 | ||
1471 | keyword: is one of | |
1472 | ||
ec4404a7 | 1473 | align |
dbb8b280 | 1474 | callsite |
4fa992a5 MD |
1475 | const |
1476 | char | |
2fa70eba | 1477 | clock |
4fa992a5 MD |
1478 | double |
1479 | enum | |
570ecabe | 1480 | env |
4fa992a5 MD |
1481 | event |
1482 | floating_point | |
1483 | float | |
1484 | integer | |
1485 | int | |
1486 | long | |
1487 | short | |
1488 | signed | |
1489 | stream | |
1490 | string | |
1491 | struct | |
1492 | trace | |
3e1e1a78 | 1493 | typealias |
4fa992a5 MD |
1494 | typedef |
1495 | unsigned | |
1496 | variant | |
1497 | void | |
1498 | _Bool | |
1499 | _Complex | |
1500 | _Imaginary | |
1501 | ||
1502 | ||
1503 | 1.3) Identifiers | |
1504 | ||
1505 | identifier: | |
1506 | identifier-nondigit | |
1507 | identifier identifier-nondigit | |
1508 | identifier digit | |
1509 | ||
1510 | identifier-nondigit: | |
1511 | nondigit | |
1512 | universal-character-name | |
1513 | any other implementation-defined characters | |
1514 | ||
1515 | nondigit: | |
1516 | _ | |
1517 | [a-zA-Z] /* regular expression */ | |
1518 | ||
1519 | digit: | |
1520 | [0-9] /* regular expression */ | |
1521 | ||
1522 | 1.4) Universal character names | |
1523 | ||
1524 | universal-character-name: | |
1525 | \u hex-quad | |
1526 | \U hex-quad hex-quad | |
1527 | ||
1528 | hex-quad: | |
1529 | hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit | |
1530 | ||
1531 | 1.5) Constants | |
1532 | ||
1533 | constant: | |
1534 | integer-constant | |
1535 | enumeration-constant | |
1536 | character-constant | |
1537 | ||
1538 | integer-constant: | |
1539 | decimal-constant integer-suffix-opt | |
1540 | octal-constant integer-suffix-opt | |
1541 | hexadecimal-constant integer-suffix-opt | |
1542 | ||
1543 | decimal-constant: | |
1544 | nonzero-digit | |
1545 | decimal-constant digit | |
1546 | ||
1547 | octal-constant: | |
1548 | 0 | |
1549 | octal-constant octal-digit | |
1550 | ||
1551 | hexadecimal-constant: | |
1552 | hexadecimal-prefix hexadecimal-digit | |
1553 | hexadecimal-constant hexadecimal-digit | |
1554 | ||
1555 | hexadecimal-prefix: | |
1556 | 0x | |
1557 | 0X | |
1558 | ||
1559 | nonzero-digit: | |
1560 | [1-9] | |
1561 | ||
1562 | integer-suffix: | |
1563 | unsigned-suffix long-suffix-opt | |
1564 | unsigned-suffix long-long-suffix | |
1565 | long-suffix unsigned-suffix-opt | |
1566 | long-long-suffix unsigned-suffix-opt | |
1567 | ||
1568 | unsigned-suffix: | |
1569 | u | |
1570 | U | |
1571 | ||
1572 | long-suffix: | |
1573 | l | |
1574 | L | |
1575 | ||
1576 | long-long-suffix: | |
1577 | ll | |
1578 | LL | |
1579 | ||
4fa992a5 MD |
1580 | enumeration-constant: |
1581 | identifier | |
1582 | string-literal | |
1583 | ||
1584 | character-constant: | |
1585 | ' c-char-sequence ' | |
1586 | L' c-char-sequence ' | |
1587 | ||
1588 | c-char-sequence: | |
1589 | c-char | |
1590 | c-char-sequence c-char | |
1591 | ||
1592 | c-char: | |
1593 | any member of source charset except single-quote ('), backslash | |
1594 | (\), or new-line character. | |
1595 | escape-sequence | |
1596 | ||
1597 | escape-sequence: | |
1598 | simple-escape-sequence | |
1599 | octal-escape-sequence | |
1600 | hexadecimal-escape-sequence | |
1601 | universal-character-name | |
1602 | ||
1603 | simple-escape-sequence: one of | |
1604 | \' \" \? \\ \a \b \f \n \r \t \v | |
1605 | ||
1606 | octal-escape-sequence: | |
1607 | \ octal-digit | |
1608 | \ octal-digit octal-digit | |
1609 | \ octal-digit octal-digit octal-digit | |
1610 | ||
1611 | hexadecimal-escape-sequence: | |
1612 | \x hexadecimal-digit | |
1613 | hexadecimal-escape-sequence hexadecimal-digit | |
1614 | ||
1615 | 1.6) String literals | |
1616 | ||
1617 | string-literal: | |
1618 | " s-char-sequence-opt " | |
1619 | L" s-char-sequence-opt " | |
1620 | ||
1621 | s-char-sequence: | |
1622 | s-char | |
1623 | s-char-sequence s-char | |
1624 | ||
1625 | s-char: | |
1626 | any member of source charset except double-quote ("), backslash | |
1627 | (\), or new-line character. | |
1628 | escape-sequence | |
1629 | ||
1630 | 1.7) Punctuators | |
1631 | ||
1632 | punctuator: one of | |
1633 | [ ] ( ) { } . -> * + - < > : ; ... = , | |
1634 | ||
1635 | ||
1636 | 2) Phrase structure grammar | |
1637 | ||
1638 | primary-expression: | |
1639 | identifier | |
1640 | constant | |
1641 | string-literal | |
1642 | ( unary-expression ) | |
1643 | ||
1644 | postfix-expression: | |
1645 | primary-expression | |
1646 | postfix-expression [ unary-expression ] | |
1647 | postfix-expression . identifier | |
1648 | postfix-expressoin -> identifier | |
1649 | ||
1650 | unary-expression: | |
1651 | postfix-expression | |
1652 | unary-operator postfix-expression | |
1653 | ||
1654 | unary-operator: one of | |
1655 | + - | |
1656 | ||
4fa992a5 MD |
1657 | assignment-operator: |
1658 | = | |
1659 | ||
b9606a77 MD |
1660 | type-assignment-operator: |
1661 | := | |
1662 | ||
4fa992a5 | 1663 | constant-expression-range: |
73d61ac3 | 1664 | unary-expression ... unary-expression |
4fa992a5 MD |
1665 | |
1666 | 2.2) Declarations: | |
1667 | ||
1668 | declaration: | |
689e04b4 | 1669 | declaration-specifiers declarator-list-opt ; |
4fa992a5 MD |
1670 | ctf-specifier ; |
1671 | ||
1672 | declaration-specifiers: | |
689e04b4 | 1673 | storage-class-specifier declaration-specifiers-opt |
4fa992a5 MD |
1674 | type-specifier declaration-specifiers-opt |
1675 | type-qualifier declaration-specifiers-opt | |
1676 | ||
1677 | declarator-list: | |
1678 | declarator | |
1679 | declarator-list , declarator | |
1680 | ||
d285084f MD |
1681 | abstract-declarator-list: |
1682 | abstract-declarator | |
1683 | abstract-declarator-list , abstract-declarator | |
1684 | ||
4fa992a5 MD |
1685 | storage-class-specifier: |
1686 | typedef | |
1687 | ||
1688 | type-specifier: | |
1689 | void | |
1690 | char | |
1691 | short | |
1692 | int | |
1693 | long | |
1694 | float | |
1695 | double | |
1696 | signed | |
1697 | unsigned | |
1698 | _Bool | |
1699 | _Complex | |
cfdd51ec | 1700 | _Imaginary |
9dfcfc0f MD |
1701 | struct-specifier |
1702 | variant-specifier | |
4fa992a5 MD |
1703 | enum-specifier |
1704 | typedef-name | |
1705 | ctf-type-specifier | |
1706 | ||
ec4404a7 | 1707 | align-attribute: |
73d61ac3 | 1708 | align ( unary-expression ) |
ec4404a7 | 1709 | |
4fa992a5 | 1710 | struct-specifier: |
ec4404a7 MD |
1711 | struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt |
1712 | struct identifier align-attribute-opt | |
4fa992a5 MD |
1713 | |
1714 | struct-or-variant-declaration-list: | |
1715 | struct-or-variant-declaration | |
1716 | struct-or-variant-declaration-list struct-or-variant-declaration | |
1717 | ||
1718 | struct-or-variant-declaration: | |
1719 | specifier-qualifier-list struct-or-variant-declarator-list ; | |
eacb16d1 | 1720 | declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt declarator-list ; |
6143bab7 MD |
1721 | typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list ; |
1722 | typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list ; | |
4fa992a5 MD |
1723 | |
1724 | specifier-qualifier-list: | |
1725 | type-specifier specifier-qualifier-list-opt | |
1726 | type-qualifier specifier-qualifier-list-opt | |
1727 | ||
1728 | struct-or-variant-declarator-list: | |
1729 | struct-or-variant-declarator | |
1730 | struct-or-variant-declarator-list , struct-or-variant-declarator | |
1731 | ||
1732 | struct-or-variant-declarator: | |
1733 | declarator | |
73d61ac3 | 1734 | declarator-opt : unary-expression |
4fa992a5 MD |
1735 | |
1736 | variant-specifier: | |
1737 | variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list } | |
1738 | variant identifier variant-tag | |
1739 | ||
1740 | variant-tag: | |
37ab95c3 | 1741 | < unary-expression > |
4fa992a5 MD |
1742 | |
1743 | enum-specifier: | |
1744 | enum identifier-opt { enumerator-list } | |
1745 | enum identifier-opt { enumerator-list , } | |
1746 | enum identifier | |
a9b83695 MD |
1747 | enum identifier-opt : declaration-specifiers { enumerator-list } |
1748 | enum identifier-opt : declaration-specifiers { enumerator-list , } | |
4fa992a5 MD |
1749 | |
1750 | enumerator-list: | |
1751 | enumerator | |
1752 | enumerator-list , enumerator | |
1753 | ||
1754 | enumerator: | |
1755 | enumeration-constant | |
8d2d41f7 MD |
1756 | enumeration-constant assignment-operator unary-expression |
1757 | enumeration-constant assignment-operator constant-expression-range | |
4fa992a5 MD |
1758 | |
1759 | type-qualifier: | |
1760 | const | |
1761 | ||
1762 | declarator: | |
1763 | pointer-opt direct-declarator | |
1764 | ||
1765 | direct-declarator: | |
1766 | identifier | |
1767 | ( declarator ) | |
1ab22b2a | 1768 | direct-declarator [ unary-expression ] |
4fa992a5 | 1769 | |
d285084f MD |
1770 | abstract-declarator: |
1771 | pointer-opt direct-abstract-declarator | |
1772 | ||
1773 | direct-abstract-declarator: | |
1774 | identifier-opt | |
1775 | ( abstract-declarator ) | |
1ab22b2a | 1776 | direct-abstract-declarator [ unary-expression ] |
d285084f MD |
1777 | direct-abstract-declarator [ ] |
1778 | ||
4fa992a5 | 1779 | pointer: |
3b0f8e4d MD |
1780 | * type-qualifier-list-opt |
1781 | * type-qualifier-list-opt pointer | |
4fa992a5 MD |
1782 | |
1783 | type-qualifier-list: | |
1784 | type-qualifier | |
1785 | type-qualifier-list type-qualifier | |
1786 | ||
4fa992a5 MD |
1787 | typedef-name: |
1788 | identifier | |
1789 | ||
1790 | 2.3) CTF-specific declarations | |
1791 | ||
1792 | ctf-specifier: | |
662baf84 | 1793 | clock { ctf-assignment-expression-list-opt } |
4fa992a5 MD |
1794 | event { ctf-assignment-expression-list-opt } |
1795 | stream { ctf-assignment-expression-list-opt } | |
570ecabe | 1796 | env { ctf-assignment-expression-list-opt } |
4fa992a5 | 1797 | trace { ctf-assignment-expression-list-opt } |
555f54e6 | 1798 | callsite { ctf-assignment-expression-list-opt } |
b12919a5 MD |
1799 | typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list |
1800 | typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list | |
4fa992a5 MD |
1801 | |
1802 | ctf-type-specifier: | |
1803 | floating_point { ctf-assignment-expression-list-opt } | |
1804 | integer { ctf-assignment-expression-list-opt } | |
1805 | string { ctf-assignment-expression-list-opt } | |
7609d3c7 | 1806 | string |
4fa992a5 MD |
1807 | |
1808 | ctf-assignment-expression-list: | |
13441bf5 MD |
1809 | ctf-assignment-expression ; |
1810 | ctf-assignment-expression-list ctf-assignment-expression ; | |
4fa992a5 MD |
1811 | |
1812 | ctf-assignment-expression: | |
1813 | unary-expression assignment-operator unary-expression | |
1814 | unary-expression type-assignment-operator type-specifier | |
eacb16d1 | 1815 | declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt declarator-list |
6143bab7 MD |
1816 | typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list |
1817 | typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list |