Add alignment explanation and struct align() attribute
[ctf.git] / common-trace-format-proposal.txt
CommitLineData
5ba9f198 1
4767a9e7 2RFC: Common Trace Format (CTF) Proposal (pre-v1.7)
5ba9f198
MD
3
4Mathieu Desnoyers, EfficiOS Inc.
5
6The goal of the present document is to propose a trace format that suits the
cc089c3a 7needs of the embedded, telecom, high-performance and kernel communities. It is
5ba9f198 8based on the Common Trace Format Requirements (v1.4) document. It is designed to
cc089c3a 9allow traces to be natively generated by the Linux kernel, Linux user-space
6c7226e9
MD
10applications written in C/C++, and hardware components. One major element of
11CTF is the Trace Stream Description Language (TSDL) which flexibility
12enables description of various binary trace stream layouts.
cc089c3a
MD
13
14The latest version of this document can be found at:
15
16 git tree: git://git.efficios.com/ctf.git
17 gitweb: http://git.efficios.com/?p=ctf.git
5ba9f198
MD
18
19A reference implementation of a library to read and write this trace format is
20being implemented within the BabelTrace project, a converter between trace
21formats. The development tree is available at:
22
23 git tree: git://git.efficios.com/babeltrace.git
24 gitweb: http://git.efficios.com/?p=babeltrace.git
25
26
271. Preliminary definitions
28
3bf79539
MD
29 - Event Trace: An ordered sequence of events.
30 - Event Stream: An ordered sequence of events, containing a subset of the
31 trace event types.
32 - Event Packet: A sequence of physically contiguous events within an event
33 stream.
5ba9f198
MD
34 - Event: This is the basic entry in a trace. (aka: a trace record).
35 - An event identifier (ID) relates to the class (a type) of event within
3bf79539
MD
36 an event stream.
37 e.g. event: irq_entry.
5ba9f198
MD
38 - An event (or event record) relates to a specific instance of an event
39 class.
3bf79539
MD
40 e.g. event: irq_entry, at time X, on CPU Y
41 - Source Architecture: Architecture writing the trace.
42 - Reader Architecture: Architecture reading the trace.
5ba9f198
MD
43
44
452. High-level representation of a trace
46
3bf79539
MD
47A trace is divided into multiple event streams. Each event stream contains a
48subset of the trace event types.
5ba9f198 49
3bf79539
MD
50The final output of the trace, after its generation and optional transport over
51the network, is expected to be either on permanent or temporary storage in a
52virtual file system. Because each event stream is appended to while a trace is
53being recorded, each is associated with a separate file for output. Therefore,
54a stored trace can be represented as a directory containing one file per stream.
5ba9f198 55
6672e9e1
MD
56Meta-data description associated with the trace contains information on
57trace event types expressed in the Trace Stream Description Language
58(TSDL). This language describes:
5ba9f198
MD
59
60- Trace version.
61- Types available.
6672e9e1 62- Per-trace event header description.
3bf79539 63- Per-stream event header description.
6672e9e1 64- Per-stream event context description.
5ba9f198 65- Per-event
3bf79539 66 - Event type to stream mapping.
5ba9f198
MD
67 - Event type to name mapping.
68 - Event type to ID mapping.
6672e9e1 69 - Event context description.
5ba9f198
MD
70 - Event fields description.
71
72
3bf79539 733. Event stream
5ba9f198 74
6672e9e1
MD
75An event stream can be divided into contiguous event packets of variable
76size. These subdivisions have a variable size. An event packet can
77contain a certain amount of padding at the end. The stream header is
78repeated at the beginning of each event packet. The rationale for the
79event stream design choices is explained in Appendix B. Stream Header
80Rationale.
5ba9f198 81
3bf79539
MD
82The event stream header will therefore be referred to as the "event packet
83header" throughout the rest of this document.
5ba9f198
MD
84
85
864. Types
87
1fad7a85
MD
88Types are organized as type classes. Each type class belong to either of two
89kind of types: basic types or compound types.
90
5ba9f198
MD
914.1 Basic types
92
1fad7a85
MD
93A basic type is a scalar type, as described in this section. It includes
94integers, GNU/C bitfields, enumerations, and floating point values.
5ba9f198
MD
95
964.1.1 Type inheritance
97
80fd2569
MD
98Type specifications can be inherited to allow deriving types from a
99type class. For example, see the uint32_t named type derived from the "integer"
100type class below ("Integers" section). Types have a precise binary
101representation in the trace. A type class has methods to read and write these
102types, but must be derived into a type to be usable in an event field.
5ba9f198
MD
103
1044.1.2 Alignment
105
106We define "byte-packed" types as aligned on the byte size, namely 8-bit.
107We define "bit-packed" types as following on the next bit, as defined by the
370eae99 108"Integers" section.
5ba9f198 109
6672e9e1 110Each basic type must specify its alignment, in bits. Examples of
ec4404a7
MD
111possible alignments are: bit-packed (align = 1), byte-packed (align =
1128), or word-aligned (e.g. align = 32 or align = 64). The choice depends
113on the architecture preference and compactness vs performance trade-offs
114of the implementation. Architectures providing fast unaligned write
115byte-packed basic types to save space, aligning each type on byte
116boundaries (8-bit). Architectures with slow unaligned writes align types
117on specific alignment values. If no specific alignment is declared for a
118type, it is assumed to be bit-packed for integers with size not multiple
119of 8 bits and for gcc bitfields. All other basic types are byte-packed
120by default. It is however recommended to always specify the alignment
121explicitly. Alignment values must be power of two. Compound types are
122aligned as specified in their individual specification.
5ba9f198 123
6672e9e1 124TSDL meta-data attribute representation of a specific alignment:
5ba9f198
MD
125
126 align = value; /* value in bits */
127
1284.1.3 Byte order
129
3bf79539
MD
130By default, the native endianness of the source architecture the trace is used.
131Byte order can be overridden for a basic type by specifying a "byte_order"
132attribute. Typical use-case is to specify the network byte order (big endian:
133"be") to save data captured from the network into the trace without conversion.
134If not specified, the byte order is native.
5ba9f198 135
6672e9e1 136TSDL meta-data representation:
5ba9f198
MD
137
138 byte_order = native OR network OR be OR le; /* network and be are aliases */
139
1404.1.4 Size
141
142Type size, in bits, for integers and floats is that returned by "sizeof()" in C
143multiplied by CHAR_BIT.
144We require the size of "char" and "unsigned char" types (CHAR_BIT) to be fixed
145to 8 bits for cross-endianness compatibility.
146
6672e9e1 147TSDL meta-data representation:
5ba9f198
MD
148
149 size = value; (value is in bits)
150
1514.1.5 Integers
152
6672e9e1
MD
153Signed integers are represented in two-complement. Integer alignment,
154size, signedness and byte ordering are defined in the TSDL meta-data.
155Integers aligned on byte size (8-bit) and with length multiple of byte
156size (8-bit) correspond to the C99 standard integers. In addition,
157integers with alignment and/or size that are _not_ a multiple of the
158byte size are permitted; these correspond to the C99 standard bitfields,
159with the added specification that the CTF integer bitfields have a fixed
160binary representation. A MIT-licensed reference implementation of the
161CTF portable bitfields is available at:
5ba9f198
MD
162
163 http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h
164
165Binary representation of integers:
166
167- On little and big endian:
168 - Within a byte, high bits correspond to an integer high bits, and low bits
169 correspond to low bits.
170- On little endian:
171 - Integer across multiple bytes are placed from the less significant to the
172 most significant.
173 - Consecutive integers are placed from lower bits to higher bits (even within
174 a byte).
175- On big endian:
176 - Integer across multiple bytes are placed from the most significant to the
177 less significant.
178 - Consecutive integers are placed from higher bits to lower bits (even within
179 a byte).
180
181This binary representation is derived from the bitfield implementation in GCC
182for little and big endian. However, contrary to what GCC does, integers can
6672e9e1 183cross units boundaries (no padding is required). Padding can be explicitly
5ba9f198
MD
184added (see 4.1.6 GNU/C bitfields) to follow the GCC layout if needed.
185
6672e9e1 186TSDL meta-data representation:
5ba9f198 187
80fd2569 188 integer {
5ba9f198
MD
189 signed = true OR false; /* default false */
190 byte_order = native OR network OR be OR le; /* default native */
191 size = value; /* value in bits, no default */
192 align = value; /* value in bits */
2152348f 193 }
5ba9f198 194
80fd2569 195Example of type inheritance (creation of a uint32_t named type):
5ba9f198 196
359894ac 197typealias integer {
9e4e34e9 198 size = 32;
5ba9f198
MD
199 signed = false;
200 align = 32;
38b8da21 201} := uint32_t;
5ba9f198 202
80fd2569 203Definition of a named 5-bit signed bitfield:
5ba9f198 204
359894ac 205typealias integer {
5ba9f198
MD
206 size = 5;
207 signed = true;
208 align = 1;
38b8da21 209} := int5_t;
5ba9f198
MD
210
2114.1.6 GNU/C bitfields
212
213The GNU/C bitfields follow closely the integer representation, with a
214particularity on alignment: if a bitfield cannot fit in the current unit, the
80fd2569
MD
215unit is padded and the bitfield starts at the following unit. The unit size is
216defined by the size of the type "unit_type".
5ba9f198 217
6672e9e1 218TSDL meta-data representation:
80fd2569
MD
219
220 unit_type name:size:
221
5ba9f198
MD
222As an example, the following structure declared in C compiled by GCC:
223
224struct example {
225 short a:12;
226 short b:5;
227};
228
2152348f
MD
229The example structure is aligned on the largest element (short). The second
230bitfield would be aligned on the next unit boundary, because it would not fit in
231the current unit.
5ba9f198
MD
232
2334.1.7 Floating point
234
6672e9e1 235The floating point values byte ordering is defined in the TSDL meta-data.
5ba9f198
MD
236
237Floating point values follow the IEEE 754-2008 standard interchange formats.
238Description of the floating point values include the exponent and mantissa size
239in bits. Some requirements are imposed on the floating point values:
240
241- FLT_RADIX must be 2.
242- mant_dig is the number of digits represented in the mantissa. It is specified
243 by the ISO C99 standard, section 5.2.4, as FLT_MANT_DIG, DBL_MANT_DIG and
244 LDBL_MANT_DIG as defined by <float.h>.
245- exp_dig is the number of digits represented in the exponent. Given that
246 mant_dig is one bit more than its actual size in bits (leading 1 is not
247 needed) and also given that the sign bit always takes one bit, exp_dig can be
248 specified as:
249
250 - sizeof(float) * CHAR_BIT - FLT_MANT_DIG
251 - sizeof(double) * CHAR_BIT - DBL_MANT_DIG
252 - sizeof(long double) * CHAR_BIT - LDBL_MANT_DIG
253
6672e9e1 254TSDL meta-data representation:
5ba9f198 255
80fd2569 256floating_point {
ec4404a7
MD
257 exp_dig = value;
258 mant_dig = value;
259 byte_order = native OR network OR be OR le;
260 align = value;
2152348f 261}
5ba9f198
MD
262
263Example of type inheritance:
264
359894ac 265typealias floating_point {
5ba9f198
MD
266 exp_dig = 8; /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */
267 mant_dig = 24; /* FLT_MANT_DIG */
268 byte_order = native;
ec4404a7 269 align = 32;
38b8da21 270} := float;
5ba9f198
MD
271
272TODO: define NaN, +inf, -inf behavior.
273
ec4404a7
MD
274Bit-packed, byte-packed or larger alignments can be used for floating
275point values, similarly to integers.
276
5ba9f198
MD
2774.1.8 Enumerations
278
279Enumerations are a mapping between an integer type and a table of strings. The
280numerical representation of the enumeration follows the integer type specified
6672e9e1
MD
281by the meta-data. The enumeration mapping table is detailed in the enumeration
282description within the meta-data. The mapping table maps inclusive value
283ranges (or single values) to strings. Instead of being limited to simple
3bf79539 284"value -> string" mappings, these enumerations map
80fd2569 285"[ start_value ... end_value ] -> string", which map inclusive ranges of
3bf79539
MD
286values to strings. An enumeration from the C language can be represented in
287this format by having the same start_value and end_value for each element, which
288is in fact a range of size 1. This single-value range is supported without
4767a9e7 289repeating the start and end values with the value = string declaration.
80fd2569 290
a9b83695 291enum name : integer_type {
359894ac 292 somestring = start_value1 ... end_value1,
80fd2569
MD
293 "other string" = start_value2 ... end_value2,
294 yet_another_string, /* will be assigned to end_value2 + 1 */
295 "some other string" = value,
296 ...
297};
298
299If the values are omitted, the enumeration starts at 0 and increment of 1 for
300each entry:
301
a9b83695 302enum name : unsigned int {
80fd2569
MD
303 ZERO,
304 ONE,
305 TWO,
306 TEN = 10,
307 ELEVEN,
3bf79539 308};
5ba9f198 309
80fd2569 310Overlapping ranges within a single enumeration are implementation defined.
5ba9f198 311
2152348f
MD
312A nameless enumeration can be declared as a field type or as part of a typedef:
313
a9b83695 314enum : integer_type {
2152348f
MD
315 ...
316}
317
c2742c56
MD
318Enumerations omitting the container type ": integer_type" use the "int"
319type (for compatibility with C99). The "int" type must be previously
320declared. E.g.:
321
322typealias integer { size = 32; align = 32; signed = true } := int;
323
324enum {
325 ...
326}
327
1fad7a85 328
5ba9f198
MD
3294.2 Compound types
330
1fad7a85
MD
331Compound are aggregation of type declarations. Compound types include
332structures, variant, arrays, sequences, and strings.
333
5ba9f198
MD
3344.2.1 Structures
335
336Structures are aligned on the largest alignment required by basic types
337contained within the structure. (This follows the ISO/C standard for structures)
338
6672e9e1 339TSDL meta-data representation of a named structure:
5ba9f198 340
80fd2569
MD
341struct name {
342 field_type field_name;
343 field_type field_name;
344 ...
345};
5ba9f198
MD
346
347Example:
348
80fd2569
MD
349struct example {
350 integer { /* Nameless type */
351 size = 16;
352 signed = true;
353 align = 16;
354 } first_field_name;
6672e9e1 355 uint64_t second_field_name; /* Named type declared in the meta-data */
3bf79539 356};
5ba9f198
MD
357
358The fields are placed in a sequence next to each other. They each possess a
359field name, which is a unique identifier within the structure.
360
2152348f 361A nameless structure can be declared as a field type or as part of a typedef:
80fd2569
MD
362
363struct {
364 ...
2152348f 365}
80fd2569 366
ec4404a7
MD
367Alignment for a structure compound type can be forced to a minimum value
368by adding an "align" specifier after the declaration of a structure
369body. This attribute is read as: align(value). The value is specified in
370bits. The structure will be aligned on the maximum value between this
371attribute and the alignment required by the basic types contained within
372the structure. e.g.
373
374struct {
375 ...
376} align(32)
377
77a98c82 3784.2.2 Variants (Discriminated/Tagged Unions)
fcba70d4 379
fdf2bb05
MD
380A CTF variant is a selection between different types. A CTF variant must
381always be defined within the scope of a structure or within fields
382contained within a structure (defined recursively). A "tag" enumeration
383field must appear in either the same lexical scope, prior to the variant
384field (in field declaration order), in an uppermost lexical scope (see
6c7226e9 385Section 7.3.1), or in an uppermost dynamic scope (see Section 7.3.2).
fdf2bb05
MD
386The type selection is indicated by the mapping from the enumeration
387value to the string used as variant type selector. The field to use as
388tag is specified by the "tag_field", specified between "< >" after the
389"variant" keyword for unnamed variants, and after "variant name" for
390named variants.
fcba70d4
MD
391
392The alignment of the variant is the alignment of the type as selected by the tag
393value for the specific instance of the variant. The alignment of the type
394containing the variant is independent of the variant alignment. The size of the
395variant is the size as selected by the tag value for the specific instance of
396the variant.
397
398A named variant declaration followed by its definition within a structure
399declaration:
400
401variant name {
402 field_type sel1;
403 field_type sel2;
404 field_type sel3;
405 ...
406};
407
408struct {
a9b83695 409 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
fcba70d4
MD
410 ...
411 variant name <tag_field> v;
412}
413
414An unnamed variant definition within a structure is expressed by the following
6672e9e1 415TSDL meta-data:
fcba70d4
MD
416
417struct {
a9b83695 418 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
fcba70d4
MD
419 ...
420 variant <tag_field> {
421 field_type sel1;
422 field_type sel2;
423 field_type sel3;
424 ...
425 } v;
426}
427
428Example of a named variant within a sequence that refers to a single tag field:
429
430variant example {
431 uint32_t a;
432 uint64_t b;
433 short c;
434};
435
436struct {
a9b83695 437 enum : uint2_t { a, b, c } choice;
15850440 438 variant example <choice> v[unsigned int];
fcba70d4
MD
439}
440
441Example of an unnamed variant:
442
443struct {
a9b83695 444 enum : uint2_t { a, b, c, d } choice;
fcba70d4
MD
445 /* Unrelated fields can be added between the variant and its tag */
446 int32_t somevalue;
447 variant <choice> {
448 uint32_t a;
449 uint64_t b;
450 short c;
451 struct {
452 unsigned int field1;
453 uint64_t field2;
454 } d;
455 } s;
456}
457
458Example of an unnamed variant within an array:
459
460struct {
a9b83695 461 enum : uint2_t { a, b, c } choice;
fcba70d4
MD
462 variant <choice> {
463 uint32_t a;
464 uint64_t b;
465 short c;
15850440 466 } v[10];
fcba70d4
MD
467}
468
469Example of a variant type definition within a structure, where the defined type
470is then declared within an array of structures. This variant refers to a tag
471located in an upper lexical scope. This example clearly shows that a variant
472type definition referring to the tag "x" uses the closest preceding field from
473the lexical scope of the type definition.
474
475struct {
a9b83695 476 enum : uint2_t { a, b, c, d } x;
fcba70d4
MD
477
478 typedef variant <x> { /*
479 * "x" refers to the preceding "x" enumeration in the
480 * lexical scope of the type definition.
481 */
482 uint32_t a;
483 uint64_t b;
484 short c;
485 } example_variant;
486
487 struct {
a9b83695 488 enum : int { x, y, z } x; /* This enumeration is not used by "v". */
fcba70d4 489 example_variant v; /*
a9b83695 490 * "v" uses the "enum : uint2_t { a, b, c, d }"
fcba70d4
MD
491 * tag.
492 */
493 } a[10];
494}
495
4964.2.3 Arrays
5ba9f198 497
6672e9e1
MD
498Arrays are fixed-length. Their length is declared in the type
499declaration within the meta-data. They contain an array of "inner type"
500elements, which can refer to any type not containing the type of the
501array being declared (no circular dependency). The length is the number
502of elements in an array.
5ba9f198 503
6672e9e1 504TSDL meta-data representation of a named array:
80fd2569
MD
505
506typedef elem_type name[length];
5ba9f198 507
2152348f 508A nameless array can be declared as a field type within a structure, e.g.:
5ba9f198 509
2152348f 510 uint8_t field_name[10];
80fd2569 511
ec4404a7 512Arrays are always aligned on their element alignment requirement.
5ba9f198 513
fcba70d4 5144.2.4 Sequences
5ba9f198
MD
515
516Sequences are dynamically-sized arrays. They start with an integer that specify
517the length of the sequence, followed by an array of "inner type" elements.
3bf79539 518The length is the number of elements in the sequence.
5ba9f198 519
6672e9e1 520TSDL meta-data representation for a named sequence:
80fd2569
MD
521
522typedef elem_type name[length_type];
523
524A nameless sequence can be declared as a field type, e.g.:
525
80fd2569
MD
526long field_name[int];
527
528The length type follows the integer types specifications, and the sequence
5ba9f198
MD
529elements follow the "array" specifications.
530
fcba70d4 5314.2.5 Strings
5ba9f198
MD
532
533Strings are an array of bytes of variable size and are terminated by a '\0'
6672e9e1
MD
534"NULL" character. Their encoding is described in the TSDL meta-data. In
535absence of encoding attribute information, the default encoding is
536UTF-8.
5ba9f198 537
6672e9e1 538TSDL meta-data representation of a named string type:
80fd2569 539
359894ac 540typealias string {
5ba9f198 541 encoding = UTF8 OR ASCII;
38b8da21 542} := name;
5ba9f198 543
80fd2569
MD
544A nameless string type can be declared as a field type:
545
546string field_name; /* Use default UTF8 encoding */
5ba9f198 547
ec4404a7
MD
548Strings are always aligned on byte size.
549
3bf79539
MD
5505. Event Packet Header
551
6672e9e1
MD
552The event packet header consists of two parts: the "event packet header"
553is the same for all streams of a trace. The second part, the "event
554packet context", is described on a per-stream basis. Both are described
555in the TSDL meta-data. The packets are aligned on architecture-page-sized
556addresses.
3bf79539 557
6672e9e1 558Event packet header (all fields are optional, specified by TSDL meta-data):
3bf79539 559
6672e9e1
MD
560- Magic number (CTF magic number: 0xC1FC1FC1) specifies that this is a
561 CTF packet. This magic number is optional, but when present, it should
562 come at the very beginning of the packet.
563- Trace UUID, used to ensure the event packet match the meta-data used.
564 (note: we cannot use a meta-data checksum in every cases instead of a
565 UUID because meta-data can be appended to while tracing is active)
566 This field is optional.
567- Stream ID, used as reference to stream description in meta-data.
568 This field is optional if there is only one stream description in the
569 meta-data, but becomes required if there are more than one stream in
570 the TSDL meta-data description.
3bf79539 571
6672e9e1 572Event packet context (all fields are optional, specified by TSDL meta-data):
3bf79539
MD
573
574- Event packet content size (in bytes).
575- Event packet size (in bytes, includes padding).
576- Event packet content checksum (optional). Checksum excludes the event packet
577 header.
578- Per-stream event packet sequence count (to deal with UDP packet loss). The
579 number of significant sequence counter bits should also be present, so
b11853af 580 wrap-arounds are dealt with correctly.
6672e9e1 581- Time-stamp at the beginning and time-stamp at the end of the event packet.
3bf79539
MD
582 Both timestamps are written in the packet header, but sampled respectively
583 while (or before) writing the first event and while (or after) writing the
584 last event in the packet. The inclusive range between these timestamps should
585 include all event timestamps assigned to events contained within the packet.
5ba9f198 586- Events discarded count
3bf79539
MD
587 - Snapshot of a per-stream free-running counter, counting the number of
588 events discarded that were supposed to be written in the stream prior to
589 the first event in the event packet.
5ba9f198 590 * Note: producer-consumer buffer full condition should fill the current
3bf79539 591 event packet with padding so we know exactly where events have been
5ba9f198 592 discarded.
3bf79539
MD
593- Lossless compression scheme used for the event packet content. Applied
594 directly to raw data. New types of compression can be added in following
595 versions of the format.
5ba9f198
MD
596 0: no compression scheme
597 1: bzip2
598 2: gzip
3bf79539
MD
599 3: xz
600- Cypher used for the event packet content. Applied after compression.
5ba9f198
MD
601 0: no encryption
602 1: AES
3bf79539 603- Checksum scheme used for the event packet content. Applied after encryption.
5ba9f198
MD
604 0: no checksum
605 1: md5
606 2: sha1
607 3: crc32
608
6672e9e1 6095.1 Event Packet Header Description
3bf79539 610
fc5425db 611The event packet header layout is indicated by the trace packet.header
6672e9e1
MD
612field. Here is a recommended structure type for the packet header with
613the fields typically expected (although these fields are each optional):
fc5425db 614
80fd2569
MD
615struct event_packet_header {
616 uint32_t magic;
617 uint8_t trace_uuid[16];
3bf79539 618 uint32_t stream_id;
80fd2569 619};
5ba9f198 620
fc5425db
MD
621trace {
622 ...
623 packet.header := struct event_packet_header;
624};
625
6672e9e1
MD
626If the magic number is not present, tools such as "file" will have no
627mean to discover the file type.
628
629If the trace_uuid is not present, no validation that the meta-data
37b39e47
MD
630actually corresponds to the stream is performed.
631
632If the stream_id packet header field is missing, the trace can only
633contain a single stream. Its "id" field can be left out, and its events
634don't need to declare a "stream_id" field.
635
636
3bf79539
MD
6375.2 Event Packet Context Description
638
639Event packet context example. These are declared within the stream declaration
6672e9e1 640in the meta-data. All these fields are optional. If the packet size field is
6a7c61df 641missing, the whole stream only contains a single packet. If the content
f6b81726
MD
642size field is missing, the packet is filled (no padding). The content
643and packet sizes include all headers.
3bf79539
MD
644
645An example event packet context type:
646
80fd2569 647struct event_packet_context {
3bf79539
MD
648 uint64_t timestamp_begin;
649 uint64_t timestamp_end;
650 uint32_t checksum;
651 uint32_t stream_packet_count;
652 uint32_t events_discarded;
653 uint32_t cpu_id;
654 uint32_t/uint16_t content_size;
655 uint32_t/uint16_t packet_size;
656 uint8_t stream_packet_count_bits; /* Significant counter bits */
657 uint8_t compression_scheme;
658 uint8_t encryption_scheme;
3b0f8e4d 659 uint8_t checksum_scheme;
3bf79539 660};
5ba9f198 661
fcba70d4 662
5ba9f198
MD
6636. Event Structure
664
665The overall structure of an event is:
666
6672e9e1
MD
6671 - Stream Packet Context (as specified by the stream meta-data)
668 2 - Event Header (as specified by the stream meta-data)
669 3 - Stream Event Context (as specified by the stream meta-data)
670 4 - Event Context (as specified by the event meta-data)
671 5 - Event Payload (as specified by the event meta-data)
5ba9f198 672
fdf2bb05 673This structure defines an implicit dynamic scoping, where variants
7d9d7e92
MD
674located in inner structures (those with a higher number in the listing
675above) can refer to the fields of outer structures (with lower number in
6c7226e9 676the listing above). See Section 7.3 TSDL Scopes for more detail.
5ba9f198 677
fdf2bb05 6786.1 Event Header
fcba70d4 679
6672e9e1 680Event headers can be described within the meta-data. We hereby propose, as an
fcba70d4
MD
681example, two types of events headers. Type 1 accommodates streams with less than
68231 event IDs. Type 2 accommodates streams with 31 or more event IDs.
5ba9f198 683
3bf79539
MD
684One major factor can vary between streams: the number of event IDs assigned to
685a stream. Luckily, this information tends to stay relatively constant (modulo
5ba9f198 686event registration while trace is being recorded), so we can specify different
3bf79539 687representations for streams containing few event IDs and streams containing
6672e9e1
MD
688many event IDs, so we end up representing the event ID and time-stamp as
689densely as possible in each case.
5ba9f198 690
fcba70d4
MD
691The header is extended in the rare occasions where the information cannot be
692represented in the ranges available in the standard event header. They are also
3bf79539
MD
693used in the rare occasions where the data required for a field could not be
694collected: the flag corresponding to the missing field within the missing_fields
695array is then set to 1.
5ba9f198 696
6672e9e1
MD
697Types uintX_t represent an X-bit unsigned integer, as declared with
698either:
5ba9f198 699
6672e9e1
MD
700 typealias integer { size = X; align = X; signed = false } := uintX_t;
701
702 or
703
704 typealias integer { size = X; align = 1; signed = false } := uintX_t;
5ba9f198 705
fdf2bb05 7066.1.1 Type 1 - Few event IDs
5ba9f198
MD
707
708 - Aligned on 32-bit (or 8-bit if byte-packed, depending on the architecture
709 preference).
5ba9f198 710 - Native architecture byte ordering.
fcba70d4
MD
711 - For "compact" selection
712 - Fixed size: 32 bits.
713 - For "extended" selection
714 - Size depends on the architecture and variant alignment.
5ba9f198 715
80fd2569 716struct event_header_1 {
fcba70d4
MD
717 /*
718 * id: range: 0 - 30.
719 * id 31 is reserved to indicate an extended header.
720 */
a9b83695 721 enum : uint5_t { compact = 0 ... 30, extended = 31 } id;
fcba70d4
MD
722 variant <id> {
723 struct {
724 uint27_t timestamp;
725 } compact;
726 struct {
727 uint32_t id; /* 32-bit event IDs */
728 uint64_t timestamp; /* 64-bit timestamps */
729 } extended;
730 } v;
5ba9f198
MD
731};
732
5ba9f198 733
fdf2bb05 7346.1.2 Type 2 - Many event IDs
5ba9f198 735
fcba70d4 736 - Aligned on 16-bit (or 8-bit if byte-packed, depending on the architecture
5ba9f198 737 preference).
5ba9f198 738 - Native architecture byte ordering.
fcba70d4
MD
739 - For "compact" selection
740 - Size depends on the architecture and variant alignment.
741 - For "extended" selection
742 - Size depends on the architecture and variant alignment.
5ba9f198 743
80fd2569 744struct event_header_2 {
fcba70d4
MD
745 /*
746 * id: range: 0 - 65534.
747 * id 65535 is reserved to indicate an extended header.
748 */
a9b83695 749 enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;
fcba70d4
MD
750 variant <id> {
751 struct {
752 uint32_t timestamp;
753 } compact;
754 struct {
755 uint32_t id; /* 32-bit event IDs */
756 uint64_t timestamp; /* 64-bit timestamps */
757 } extended;
758 } v;
5ba9f198
MD
759};
760
5ba9f198
MD
761
7626.2 Event Context
763
6672e9e1
MD
764The event context contains information relative to the current event.
765The choice and meaning of this information is specified by the TSDL
766stream and event meta-data descriptions. The stream context is applied
767to all events within the stream. The stream context structure follows
768the event header. The event context is applied to specific events. Its
769structure follows the stream context structure.
5ba9f198 770
fcba70d4
MD
771An example of stream-level event context is to save the event payload size with
772each event, or to save the current PID with each event. These are declared
6672e9e1 773within the stream declaration within the meta-data:
5ba9f198 774
fcba70d4
MD
775 stream {
776 ...
6672e9e1 777 event.context := struct {
80fd2569
MD
778 uint pid;
779 uint16_t payload_size;
6672e9e1 780 };
fcba70d4
MD
781 };
782
783An example of event-specific event context is to declare a bitmap of missing
784fields, only appended after the stream event context if the extended event
785header is selected. NR_FIELDS is the number of fields within the event (a
786numeric value).
5ba9f198 787
fcba70d4
MD
788 event {
789 context = struct {
790 variant <id> {
791 struct { } compact;
792 struct {
793 uint1_t missing_fields[NR_FIELDS]; /* missing event fields bitmap */
794 } extended;
795 } v;
796 };
797 ...
798 }
5ba9f198
MD
799
8006.3 Event Payload
801
802An event payload contains fields specific to a given event type. The fields
6672e9e1 803belonging to an event type are described in the event-specific meta-data
5ba9f198
MD
804within a structure type.
805
8066.3.1 Padding
807
808No padding at the end of the event payload. This differs from the ISO/C standard
809for structures, but follows the CTF standard for structures. In a trace, even
810though it makes sense to align the beginning of a structure, it really makes no
811sense to add padding at the end of the structure, because structures are usually
812not followed by a structure of the same type.
813
814This trick can be done by adding a zero-length "end" field at the end of the C
815structures, and by using the offset of this field rather than using sizeof()
3bf79539 816when calculating the size of a structure (see Appendix "A. Helper macros").
5ba9f198
MD
817
8186.3.2 Alignment
819
820The event payload is aligned on the largest alignment required by types
821contained within the payload. (This follows the ISO/C standard for structures)
822
823
6c7226e9
MD
8247. Trace Stream Description Language (TSDL)
825
826The Trace Stream Description Language (TSDL) allows expression of the
827binary trace streams layout in a C99-like Domain Specific Language
828(DSL).
829
830
6672e9e1 8317.1 Meta-data
6c7226e9
MD
832
833The trace stream layout description is located in the trace meta-data.
834The meta-data is itself located in a stream identified by its name:
835"metadata".
5ba9f198 836
6672e9e1
MD
837The meta-data description can be expressed in two different formats:
838text-only and packet-based. The text-only description facilitates
839generation of meta-data and provides a convenient way to enter the
840meta-data information by hand. The packet-based meta-data provides the
841CTF stream packet facilities (checksumming, compression, encryption,
842network-readiness) for meta-data stream generated and transported by a
843tracer.
844
845The text-only meta-data file is a plain text TSDL description.
846
847The packet-based meta-data is made of "meta-data packets", which each
848start with a meta-data packet header. The packet-based meta-data
849description is detected by reading the magic number "0x75D11D57" at the
850beginning of the file. This magic number is also used to detect the
851endianness of the architecture by trying to read the CTF magic number
852and its counterpart in reversed endianness. The events within the
853meta-data stream have no event header nor event context. Each event only
854contains a "string" payload. Each meta-data packet start with a special
855packet header, specific to the meta-data stream, which contains,
856exactly:
857
858struct metadata_packet_header {
2daeaa3a 859 uint32_t magic; /* 0x75D11D57 */
6672e9e1
MD
860 uint8_t trace_uuid[16]; /* Unique Universal Identifier */
861 uint32_t checksum; /* 0 if unused */
862 uint32_t content_size; /* in bits */
863 uint32_t packet_size; /* in bits */
864 uint8_t compression_scheme; /* 0 if unused */
865 uint8_t encryption_scheme; /* 0 if unused */
866 uint8_t checksum_scheme; /* 0 if unused */
867};
868
869The packet-based meta-data can be converted to a text-only meta-data by
870concatenating all the strings in contains.
4fafe1ad 871
6672e9e1
MD
872In the textual representation of the meta-data, the text contained
873within "/*" and "*/", as well as within "//" and end of line, are
874treated as comments. Boolean values can be represented as true, TRUE,
875or 1 for true, and false, FALSE, or 0 for false. Within the string-based
876meta-data description, the trace UUID is represented as a string of
877hexadecimal digits and dashes "-". In the event packet header, the trace
878UUID is represented as an array of bytes.
fcba70d4 879
fdf2bb05 880
6c7226e9 8817.2 Declaration vs Definition
fdf2bb05
MD
882
883A declaration associates a layout to a type, without specifying where
884this type is located in the event structure hierarchy (see Section 6).
885This therefore includes typedef, typealias, as well as all type
886specifiers. In certain circumstances (typedef, structure field and
887variant field), a declaration is followed by a declarator, which specify
888the newly defined type name (for typedef), or the field name (for
889declarations located within structure and variants). Array and sequence,
890declared with square brackets ("[" "]"), are part of the declarator,
a9b83695 891similarly to C99. The enumeration base type is specified by
6c7226e9 892": enum_base", which is part of the type specifier. The variant tag
a9b83695 893name, specified between "<" ">", is also part of the type specifier.
fdf2bb05
MD
894
895A definition associates a type to a location in the event structure
b9606a77
MD
896hierarchy (see Section 6). This association is denoted by ":=", as shown
897in Section 7.3.
fdf2bb05
MD
898
899
6c7226e9 9007.3 TSDL Scopes
fdf2bb05 901
6c7226e9
MD
902TSDL uses two different types of scoping: a lexical scope is used for
903declarations and type definitions, and a dynamic scope is used for
904variants references to tag fields.
fdf2bb05 905
6c7226e9 9067.3.1 Lexical Scope
fdf2bb05 907
d285084f
MD
908Each of "trace", "stream", "event", "struct" and "variant" have their own
909nestable declaration scope, within which types can be declared using "typedef"
fdf2bb05 910and "typealias". A root declaration scope also contains all declarations
7d9d7e92 911located outside of any of the aforementioned declarations. An inner
fdf2bb05 912declaration scope can refer to type declared within its container
7d9d7e92
MD
913lexical scope prior to the inner declaration scope. Redefinition of a
914typedef or typealias is not valid, although hiding an upper scope
fdf2bb05
MD
915typedef or typealias is allowed within a sub-scope.
916
6c7226e9 9177.3.2 Dynamic Scope
fdf2bb05 918
7d9d7e92
MD
919A dynamic scope consists in the lexical scope augmented with the
920implicit event structure definition hierarchy presented at Section 6.
921The dynamic scope is only used for variant tag definitions. It is used
922at definition time to look up the location of the tag field associated
923with a variant.
924
925Therefore, variants in lower levels in the dynamic scope (e.g. event
926context) can refer to a tag field located in upper levels (e.g. in the
927event header) by specifying, in this case, the associated tag with
928<header.field_name>. This allows, for instance, the event context to
929define a variant referring to the "id" field of the event header as
930selector.
fdf2bb05
MD
931
932The target dynamic scope must be specified explicitly when referring to
933a field outside of the local static scope. The dynamic scope prefixes
934are thus:
935
e0d9e2c7 936 - Trace Packet Header: <trace.packet.header. >,
7d9d7e92
MD
937 - Stream Packet Context: <stream.packet.context. >,
938 - Event Header: <stream.event.header. >,
939 - Stream Event Context: <stream.event.context. >,
940 - Event Context: <event.context. >,
941 - Event Payload: <event.fields. >.
fdf2bb05
MD
942
943Multiple declarations of the same field name within a single scope is
944not valid. It is however valid to re-use the same field name in
945different scopes. There is no possible conflict, because the dynamic
946scope must be specified when a variant refers to a tag field located in
947a different dynamic scope.
948
457d8b0a
MD
949The information available in the dynamic scopes can be thought of as the
950current tracing context. At trace production, information about the
951current context is saved into the specified scope field levels. At trace
952consumption, for each event, the current trace context is therefore
953readable by accessing the upper dynamic scopes.
954
fdf2bb05 955
6c7226e9 9567.4 TSDL Examples
d285084f 957
6672e9e1 958The grammar representing the TSDL meta-data is presented in Appendix C.
7df6b93a 959TSDL Grammar. This section presents a rather lighter reading that
6672e9e1 960consists in examples of TSDL meta-data, with template values.
969f30c0 961
350bb633
MD
962The stream "id" can be left out if there is only one stream in the
963trace. The event "id" field can be left out if there is only one event
964in a stream.
965
5ba9f198 966trace {
fdf2bb05 967 major = value; /* Trace format version */
5ba9f198 968 minor = value;
fdf2bb05 969 uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"; /* Trace UUID */
58997e9e 970 byte_order = be OR le; /* Endianness (required) */
fc5425db
MD
971 packet.header := struct {
972 uint32_t magic;
973 uint8_t trace_uuid[16];
974 uint32_t stream_id;
975 };
3bf79539 976};
5ba9f198 977
3bf79539
MD
978stream {
979 id = stream_id;
fdf2bb05 980 /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */
4fa992a5
MD
981 event.header := event_header_1 OR event_header_2;
982 event.context := struct {
77a98c82 983 ...
3bf79539 984 };
4fa992a5 985 packet.context := struct {
77a98c82 986 ...
3bf79539
MD
987 };
988};
5ba9f198
MD
989
990event {
3d13ef1a 991 name = event_name;
3bf79539 992 id = value; /* Numeric identifier within the stream */
67f02e24 993 stream_id = stream_id;
4fa992a5 994 context := struct {
fcba70d4
MD
995 ...
996 };
4fa992a5 997 fields := struct {
80fd2569
MD
998 ...
999 };
3bf79539 1000};
5ba9f198
MD
1001
1002/* More detail on types in section 4. Types */
1003
3d13ef1a
MD
1004/*
1005 * Named types:
1006 *
4fa992a5 1007 * Type declarations behave similarly to the C standard.
3d13ef1a
MD
1008 */
1009
80af8ac6 1010typedef aliased_type_specifiers new_type_declarators;
2152348f 1011
3d13ef1a 1012/* e.g.: typedef struct example new_type_name[10]; */
80fd2569 1013
4fa992a5
MD
1014/*
1015 * typealias
1016 *
1017 * The "typealias" declaration can be used to give a name (including
80af8ac6
MD
1018 * pointer declarator specifier) to a type. It should also be used to
1019 * map basic C types (float, int, unsigned long, ...) to a CTF type.
1020 * Typealias is a superset of "typedef": it also allows assignment of a
38b8da21 1021 * simple variable identifier to a type.
4fa992a5
MD
1022 */
1023
1024typealias type_class {
80fd2569 1025 ...
38b8da21 1026} := type_specifiers type_declarator;
2152348f 1027
3d13ef1a
MD
1028/*
1029 * e.g.:
4fa992a5 1030 * typealias integer {
3d13ef1a
MD
1031 * size = 32;
1032 * align = 32;
1033 * signed = false;
38b8da21 1034 * } := struct page *;
359894ac
MD
1035 *
1036 * typealias integer {
1037 * size = 32;
1038 * align = 32;
1039 * signed = true;
38b8da21 1040 * } := int;
3d13ef1a 1041 */
80fd2569
MD
1042
1043struct name {
3bf79539
MD
1044 ...
1045};
5ba9f198 1046
fcba70d4
MD
1047variant name {
1048 ...
1049};
1050
a9b83695 1051enum name : integer_type {
3bf79539
MD
1052 ...
1053};
1054
2152348f 1055
4fa992a5
MD
1056/*
1057 * Unnamed types, contained within compound type fields, typedef or typealias.
1058 */
2152348f 1059
80fd2569
MD
1060struct {
1061 ...
2152348f 1062}
5ba9f198 1063
ec4404a7
MD
1064struct {
1065 ...
1066} align(value)
1067
fcba70d4
MD
1068variant {
1069 ...
1070}
1071
a9b83695 1072enum : integer_type {
80fd2569 1073 ...
2152348f
MD
1074}
1075
1076typedef type new_type[length];
3bf79539 1077
2152348f
MD
1078struct {
1079 type field_name[length];
1080}
1081
1082typedef type new_type[length_type];
1083
1084struct {
1085 type field_name[length_type];
1086}
1087
1088integer {
80fd2569 1089 ...
2152348f 1090}
3bf79539 1091
2152348f 1092floating_point {
80fd2569 1093 ...
2152348f
MD
1094}
1095
1096struct {
1097 integer_type field_name:size; /* GNU/C bitfield */
1098}
1099
1100struct {
1101 string field_name;
1102}
3bf79539 1103
fcba70d4 1104
3bf79539 1105A. Helper macros
5ba9f198
MD
1106
1107The two following macros keep track of the size of a GNU/C structure without
1108padding at the end by placing HEADER_END as the last field. A one byte end field
1109is used for C90 compatibility (C99 flexible arrays could be used here). Note
1110that this does not affect the effective structure size, which should always be
1111calculated with the header_sizeof() helper.
1112
1113#define HEADER_END char end_field
1114#define header_sizeof(type) offsetof(typeof(type), end_field)
3bf79539
MD
1115
1116
1117B. Stream Header Rationale
1118
1119An event stream is divided in contiguous event packets of variable size. These
1120subdivisions allow the trace analyzer to perform a fast binary search by time
1121within the stream (typically requiring to index only the event packet headers)
1122without reading the whole stream. These subdivisions have a variable size to
1123eliminate the need to transfer the event packet padding when partially filled
1124event packets must be sent when streaming a trace for live viewing/analysis.
1125An event packet can contain a certain amount of padding at the end. Dividing
1126streams into event packets is also useful for network streaming over UDP and
1127flight recorder mode tracing (a whole event packet can be swapped out of the
1128buffer atomically for reading).
1129
1130The stream header is repeated at the beginning of each event packet to allow
1131flexibility in terms of:
1132
1133 - streaming support,
1134 - allowing arbitrary buffers to be discarded without making the trace
1135 unreadable,
1136 - allow UDP packet loss handling by either dealing with missing event packet
1137 or asking for re-transmission.
1138 - transparently support flight recorder mode,
1139 - transparently support crash dump.
1140
6c7226e9
MD
1141
1142C. TSDL Grammar
fcba70d4 1143
4fa992a5 1144/*
6c7226e9 1145 * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar.
4fa992a5
MD
1146 *
1147 * Inspired from the C99 grammar:
1148 * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A)
6c7226e9
MD
1149 * and c++1x grammar (draft)
1150 * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A)
4fa992a5
MD
1151 *
1152 * Specialized for CTF needs by including only constant and declarations from
1153 * C99 (excluding function declarations), and by adding support for variants,
6c7226e9
MD
1154 * sequences and CTF-specific specifiers. Enumeration container types
1155 * semantic is inspired from c++1x enum-base.
4fa992a5
MD
1156 */
1157
11581) Lexical grammar
1159
11601.1) Lexical elements
1161
1162token:
1163 keyword
1164 identifier
1165 constant
1166 string-literal
1167 punctuator
1168
11691.2) Keywords
1170
1171keyword: is one of
1172
ec4404a7 1173align
4fa992a5
MD
1174const
1175char
1176double
1177enum
1178event
1179floating_point
1180float
1181integer
1182int
1183long
1184short
1185signed
1186stream
1187string
1188struct
1189trace
3e1e1a78 1190typealias
4fa992a5
MD
1191typedef
1192unsigned
1193variant
1194void
1195_Bool
1196_Complex
1197_Imaginary
1198
1199
12001.3) Identifiers
1201
1202identifier:
1203 identifier-nondigit
1204 identifier identifier-nondigit
1205 identifier digit
1206
1207identifier-nondigit:
1208 nondigit
1209 universal-character-name
1210 any other implementation-defined characters
1211
1212nondigit:
1213 _
1214 [a-zA-Z] /* regular expression */
1215
1216digit:
1217 [0-9] /* regular expression */
1218
12191.4) Universal character names
1220
1221universal-character-name:
1222 \u hex-quad
1223 \U hex-quad hex-quad
1224
1225hex-quad:
1226 hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit
1227
12281.5) Constants
1229
1230constant:
1231 integer-constant
1232 enumeration-constant
1233 character-constant
1234
1235integer-constant:
1236 decimal-constant integer-suffix-opt
1237 octal-constant integer-suffix-opt
1238 hexadecimal-constant integer-suffix-opt
1239
1240decimal-constant:
1241 nonzero-digit
1242 decimal-constant digit
1243
1244octal-constant:
1245 0
1246 octal-constant octal-digit
1247
1248hexadecimal-constant:
1249 hexadecimal-prefix hexadecimal-digit
1250 hexadecimal-constant hexadecimal-digit
1251
1252hexadecimal-prefix:
1253 0x
1254 0X
1255
1256nonzero-digit:
1257 [1-9]
1258
1259integer-suffix:
1260 unsigned-suffix long-suffix-opt
1261 unsigned-suffix long-long-suffix
1262 long-suffix unsigned-suffix-opt
1263 long-long-suffix unsigned-suffix-opt
1264
1265unsigned-suffix:
1266 u
1267 U
1268
1269long-suffix:
1270 l
1271 L
1272
1273long-long-suffix:
1274 ll
1275 LL
1276
4fa992a5
MD
1277enumeration-constant:
1278 identifier
1279 string-literal
1280
1281character-constant:
1282 ' c-char-sequence '
1283 L' c-char-sequence '
1284
1285c-char-sequence:
1286 c-char
1287 c-char-sequence c-char
1288
1289c-char:
1290 any member of source charset except single-quote ('), backslash
1291 (\), or new-line character.
1292 escape-sequence
1293
1294escape-sequence:
1295 simple-escape-sequence
1296 octal-escape-sequence
1297 hexadecimal-escape-sequence
1298 universal-character-name
1299
1300simple-escape-sequence: one of
1301 \' \" \? \\ \a \b \f \n \r \t \v
1302
1303octal-escape-sequence:
1304 \ octal-digit
1305 \ octal-digit octal-digit
1306 \ octal-digit octal-digit octal-digit
1307
1308hexadecimal-escape-sequence:
1309 \x hexadecimal-digit
1310 hexadecimal-escape-sequence hexadecimal-digit
1311
13121.6) String literals
1313
1314string-literal:
1315 " s-char-sequence-opt "
1316 L" s-char-sequence-opt "
1317
1318s-char-sequence:
1319 s-char
1320 s-char-sequence s-char
1321
1322s-char:
1323 any member of source charset except double-quote ("), backslash
1324 (\), or new-line character.
1325 escape-sequence
1326
13271.7) Punctuators
1328
1329punctuator: one of
1330 [ ] ( ) { } . -> * + - < > : ; ... = ,
1331
1332
13332) Phrase structure grammar
1334
1335primary-expression:
1336 identifier
1337 constant
1338 string-literal
1339 ( unary-expression )
1340
1341postfix-expression:
1342 primary-expression
1343 postfix-expression [ unary-expression ]
1344 postfix-expression . identifier
1345 postfix-expressoin -> identifier
1346
1347unary-expression:
1348 postfix-expression
1349 unary-operator postfix-expression
1350
1351unary-operator: one of
1352 + -
1353
4fa992a5
MD
1354assignment-operator:
1355 =
1356
b9606a77
MD
1357type-assignment-operator:
1358 :=
1359
4fa992a5
MD
1360constant-expression:
1361 unary-expression
1362
1363constant-expression-range:
1364 constant-expression ... constant-expression
1365
13662.2) Declarations:
1367
1368declaration:
689e04b4 1369 declaration-specifiers declarator-list-opt ;
4fa992a5
MD
1370 ctf-specifier ;
1371
1372declaration-specifiers:
689e04b4 1373 storage-class-specifier declaration-specifiers-opt
4fa992a5
MD
1374 type-specifier declaration-specifiers-opt
1375 type-qualifier declaration-specifiers-opt
1376
1377declarator-list:
1378 declarator
1379 declarator-list , declarator
1380
d285084f
MD
1381abstract-declarator-list:
1382 abstract-declarator
1383 abstract-declarator-list , abstract-declarator
1384
4fa992a5
MD
1385storage-class-specifier:
1386 typedef
1387
1388type-specifier:
1389 void
1390 char
1391 short
1392 int
1393 long
1394 float
1395 double
1396 signed
1397 unsigned
1398 _Bool
1399 _Complex
cfdd51ec 1400 _Imaginary
9dfcfc0f
MD
1401 struct-specifier
1402 variant-specifier
4fa992a5
MD
1403 enum-specifier
1404 typedef-name
1405 ctf-type-specifier
1406
ec4404a7
MD
1407align-attribute:
1408 align ( constant-expression )
1409
4fa992a5 1410struct-specifier:
ec4404a7
MD
1411 struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
1412 struct identifier align-attribute-opt
4fa992a5
MD
1413
1414struct-or-variant-declaration-list:
1415 struct-or-variant-declaration
1416 struct-or-variant-declaration-list struct-or-variant-declaration
1417
1418struct-or-variant-declaration:
1419 specifier-qualifier-list struct-or-variant-declarator-list ;
550aca33 1420 declaration-specifiers storage-class-specifier declaration-specifiers declarator-list ;
38b8da21
MD
1421 typealias declaration-specifiers abstract-declarator-list := declaration-specifiers abstract-declarator-list ;
1422 typealias declaration-specifiers abstract-declarator-list := declarator-list ;
4fa992a5
MD
1423
1424specifier-qualifier-list:
1425 type-specifier specifier-qualifier-list-opt
1426 type-qualifier specifier-qualifier-list-opt
1427
1428struct-or-variant-declarator-list:
1429 struct-or-variant-declarator
1430 struct-or-variant-declarator-list , struct-or-variant-declarator
1431
1432struct-or-variant-declarator:
1433 declarator
1434 declarator-opt : constant-expression
1435
1436variant-specifier:
1437 variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
1438 variant identifier variant-tag
1439
1440variant-tag:
1441 < identifier >
1442
1443enum-specifier:
1444 enum identifier-opt { enumerator-list }
1445 enum identifier-opt { enumerator-list , }
1446 enum identifier
a9b83695
MD
1447 enum identifier-opt : declaration-specifiers { enumerator-list }
1448 enum identifier-opt : declaration-specifiers { enumerator-list , }
4fa992a5
MD
1449
1450enumerator-list:
1451 enumerator
1452 enumerator-list , enumerator
1453
1454enumerator:
1455 enumeration-constant
1456 enumeration-constant = constant-expression
1457 enumeration-constant = constant-expression-range
1458
1459type-qualifier:
1460 const
1461
1462declarator:
1463 pointer-opt direct-declarator
1464
1465direct-declarator:
1466 identifier
1467 ( declarator )
1468 direct-declarator [ type-specifier ]
1469 direct-declarator [ constant-expression ]
1470
d285084f
MD
1471abstract-declarator:
1472 pointer-opt direct-abstract-declarator
1473
1474direct-abstract-declarator:
1475 identifier-opt
1476 ( abstract-declarator )
1477 direct-abstract-declarator [ type-specifier ]
1478 direct-abstract-declarator [ constant-expression ]
1479 direct-abstract-declarator [ ]
1480
4fa992a5 1481pointer:
3b0f8e4d
MD
1482 * type-qualifier-list-opt
1483 * type-qualifier-list-opt pointer
4fa992a5
MD
1484
1485type-qualifier-list:
1486 type-qualifier
1487 type-qualifier-list type-qualifier
1488
4fa992a5
MD
1489typedef-name:
1490 identifier
1491
14922.3) CTF-specific declarations
1493
1494ctf-specifier:
1495 event { ctf-assignment-expression-list-opt }
1496 stream { ctf-assignment-expression-list-opt }
1497 trace { ctf-assignment-expression-list-opt }
38b8da21
MD
1498 typealias declaration-specifiers abstract-declarator-list := declaration-specifiers abstract-declarator-list ;
1499 typealias declaration-specifiers abstract-declarator-list := declarator-list ;
4fa992a5
MD
1500
1501ctf-type-specifier:
1502 floating_point { ctf-assignment-expression-list-opt }
1503 integer { ctf-assignment-expression-list-opt }
1504 string { ctf-assignment-expression-list-opt }
1505
1506ctf-assignment-expression-list:
1507 ctf-assignment-expression
1508 ctf-assignment-expression-list ; ctf-assignment-expression
1509
1510ctf-assignment-expression:
1511 unary-expression assignment-operator unary-expression
1512 unary-expression type-assignment-operator type-specifier
550aca33 1513 declaration-specifiers storage-class-specifier declaration-specifiers declarator-list
38b8da21
MD
1514 typealias declaration-specifiers abstract-declarator-list := declaration-specifiers abstract-declarator-list
1515 typealias declaration-specifiers abstract-declarator-list := declarator-list
This page took 0.165363 seconds and 4 git commands to generate.