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