Clarify number of files per stream
[ctf.git] / common-trace-format-specification.txt
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4dfca05b 1Common Trace Format (CTF) Specification (pre-v1.8)
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2
3Mathieu Desnoyers, EfficiOS Inc.
4
339a7dde 5The goal of the present document is to specify a trace format that suits the
cc089c3a 6needs of the embedded, telecom, high-performance and kernel communities. It is
5ba9f198 7based on the Common Trace Format Requirements (v1.4) document. It is designed to
cc089c3a 8allow traces to be natively generated by the Linux kernel, Linux user-space
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9applications written in C/C++, and hardware components. One major element of
10CTF is the Trace Stream Description Language (TSDL) which flexibility
11enables description of various binary trace stream layouts.
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12
13The 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
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17
18A reference implementation of a library to read and write this trace format is
19being implemented within the BabelTrace project, a converter between trace
20formats. 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
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25The CE Workgroup of the Linux Foundation, Ericsson, and EfficiOS have
26sponsored this work.
27
5ba9f198 28
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29Table of Contents
30
311. Preliminary definitions
322. High-level representation of a trace
333. Event stream
344. 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
444.2 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
505. Event Packet Header
51 5.1 Event Packet Header Description
52 5.2 Event Packet Context Description
536. 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
617. 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
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701. Preliminary definitions
71
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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.
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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
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79 an event stream.
80 e.g. event: irq_entry.
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81 - An event (or event record) relates to a specific instance of an event
82 class.
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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.
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86
87
882. High-level representation of a trace
89
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90A trace is divided into multiple event streams. Each event stream contains a
91subset of the trace event types.
5ba9f198 92
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93The final output of the trace, after its generation and optional transport over
94the network, is expected to be either on permanent or temporary storage in a
95virtual file system. Because each event stream is appended to while a trace is
96being recorded, each is associated with a separate file for output. Therefore,
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97a stored trace can be represented as a directory containing zero, one or
98more files per stream.
5ba9f198 99
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100Meta-data description associated with the trace contains information on
101trace event types expressed in the Trace Stream Description Language
102(TSDL). This language describes:
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103
104- Trace version.
105- Types available.
6672e9e1 106- Per-trace event header description.
3bf79539 107- Per-stream event header description.
6672e9e1 108- Per-stream event context description.
5ba9f198 109- Per-event
3bf79539 110 - Event type to stream mapping.
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111 - Event type to name mapping.
112 - Event type to ID mapping.
6672e9e1 113 - Event context description.
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114 - Event fields description.
115
116
3bf79539 1173. Event stream
5ba9f198 118
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119An event stream can be divided into contiguous event packets of variable
120size. These subdivisions have a variable size. An event packet can
121contain a certain amount of padding at the end. The stream header is
122repeated at the beginning of each event packet. The rationale for the
123event stream design choices is explained in Appendix B. Stream Header
124Rationale.
5ba9f198 125
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126The event stream header will therefore be referred to as the "event packet
127header" throughout the rest of this document.
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128
129
1304. Types
131
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132Types are organized as type classes. Each type class belong to either of two
133kind of types: basic types or compound types.
134
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1354.1 Basic types
136
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137A basic type is a scalar type, as described in this section. It includes
138integers, GNU/C bitfields, enumerations, and floating point values.
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139
1404.1.1 Type inheritance
141
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142Type specifications can be inherited to allow deriving types from a
143type class. For example, see the uint32_t named type derived from the "integer"
144type class below ("Integers" section). Types have a precise binary
145representation in the trace. A type class has methods to read and write these
146types, but must be derived into a type to be usable in an event field.
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147
1484.1.2 Alignment
149
150We define "byte-packed" types as aligned on the byte size, namely 8-bit.
151We define "bit-packed" types as following on the next bit, as defined by the
370eae99 152"Integers" section.
5ba9f198 153
6672e9e1 154Each basic type must specify its alignment, in bits. Examples of
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155possible alignments are: bit-packed (align = 1), byte-packed (align =
1568), or word-aligned (e.g. align = 32 or align = 64). The choice depends
157on the architecture preference and compactness vs performance trade-offs
158of the implementation. Architectures providing fast unaligned write
159byte-packed basic types to save space, aligning each type on byte
160boundaries (8-bit). Architectures with slow unaligned writes align types
161on specific alignment values. If no specific alignment is declared for a
162type, it is assumed to be bit-packed for integers with size not multiple
163of 8 bits and for gcc bitfields. All other basic types are byte-packed
164by default. It is however recommended to always specify the alignment
165explicitly. Alignment values must be power of two. Compound types are
166aligned as specified in their individual specification.
5ba9f198 167
6672e9e1 168TSDL meta-data attribute representation of a specific alignment:
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169
170 align = value; /* value in bits */
171
1724.1.3 Byte order
173
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174By default, the native endianness of the source architecture the trace is used.
175Byte order can be overridden for a basic type by specifying a "byte_order"
176attribute. 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.
178If not specified, the byte order is native.
5ba9f198 179
6672e9e1 180TSDL meta-data representation:
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181
182 byte_order = native OR network OR be OR le; /* network and be are aliases */
183
1844.1.4 Size
185
186Type size, in bits, for integers and floats is that returned by "sizeof()" in C
187multiplied by CHAR_BIT.
188We require the size of "char" and "unsigned char" types (CHAR_BIT) to be fixed
189to 8 bits for cross-endianness compatibility.
190
6672e9e1 191TSDL meta-data representation:
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192
193 size = value; (value is in bits)
194
1954.1.5 Integers
196
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197Signed integers are represented in two-complement. Integer alignment,
198size, signedness and byte ordering are defined in the TSDL meta-data.
199Integers aligned on byte size (8-bit) and with length multiple of byte
200size (8-bit) correspond to the C99 standard integers. In addition,
201integers with alignment and/or size that are _not_ a multiple of the
202byte size are permitted; these correspond to the C99 standard bitfields,
203with the added specification that the CTF integer bitfields have a fixed
204binary representation. A MIT-licensed reference implementation of the
205CTF portable bitfields is available at:
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206
207 http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h
208
209Binary 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
225This binary representation is derived from the bitfield implementation in GCC
226for little and big endian. However, contrary to what GCC does, integers can
6672e9e1 227cross units boundaries (no padding is required). Padding can be explicitly
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228added (see 4.1.6 GNU/C bitfields) to follow the GCC layout if needed.
229
6672e9e1 230TSDL meta-data representation:
5ba9f198 231
80fd2569 232 integer {
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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 */
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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;
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240 /* character encoding, default: none */
241 encoding = none or UTF8 or ASCII;
2152348f 242 }
5ba9f198 243
80fd2569 244Example of type inheritance (creation of a uint32_t named type):
5ba9f198 245
359894ac 246typealias integer {
9e4e34e9 247 size = 32;
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248 signed = false;
249 align = 32;
38b8da21 250} := uint32_t;
5ba9f198 251
80fd2569 252Definition of a named 5-bit signed bitfield:
5ba9f198 253
359894ac 254typealias integer {
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255 size = 5;
256 signed = true;
257 align = 1;
38b8da21 258} := int5_t;
5ba9f198 259
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260The character encoding field can be used to specify that the integer
261must be printed as a text character when read. e.g.:
262
263typealias integer {
264 size = 8;
265 align = 8;
266 signed = false;
267 encoding = UTF8;
268} := utf_char;
269
270
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2714.1.6 GNU/C bitfields
272
273The GNU/C bitfields follow closely the integer representation, with a
274particularity on alignment: if a bitfield cannot fit in the current unit, the
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275unit is padded and the bitfield starts at the following unit. The unit size is
276defined by the size of the type "unit_type".
5ba9f198 277
6672e9e1 278TSDL meta-data representation:
80fd2569 279
d674f4b8 280 unit_type name:size;
80fd2569 281
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282As an example, the following structure declared in C compiled by GCC:
283
284struct example {
285 short a:12;
286 short b:5;
287};
288
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289The example structure is aligned on the largest element (short). The second
290bitfield would be aligned on the next unit boundary, because it would not fit in
291the current unit.
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292
2934.1.7 Floating point
294
6672e9e1 295The floating point values byte ordering is defined in the TSDL meta-data.
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296
297Floating point values follow the IEEE 754-2008 standard interchange formats.
298Description of the floating point values include the exponent and mantissa size
299in 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
6672e9e1 314TSDL meta-data representation:
5ba9f198 315
80fd2569 316floating_point {
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317 exp_dig = value;
318 mant_dig = value;
319 byte_order = native OR network OR be OR le;
320 align = value;
2152348f 321}
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322
323Example of type inheritance:
324
359894ac 325typealias floating_point {
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326 exp_dig = 8; /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */
327 mant_dig = 24; /* FLT_MANT_DIG */
328 byte_order = native;
ec4404a7 329 align = 32;
38b8da21 330} := float;
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331
332TODO: define NaN, +inf, -inf behavior.
333
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334Bit-packed, byte-packed or larger alignments can be used for floating
335point values, similarly to integers.
336
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3374.1.8 Enumerations
338
339Enumerations are a mapping between an integer type and a table of strings. The
340numerical representation of the enumeration follows the integer type specified
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341by the meta-data. The enumeration mapping table is detailed in the enumeration
342description within the meta-data. The mapping table maps inclusive value
343ranges (or single values) to strings. Instead of being limited to simple
3bf79539 344"value -> string" mappings, these enumerations map
80fd2569 345"[ start_value ... end_value ] -> string", which map inclusive ranges of
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346values to strings. An enumeration from the C language can be represented in
347this format by having the same start_value and end_value for each element, which
348is in fact a range of size 1. This single-value range is supported without
4767a9e7 349repeating the start and end values with the value = string declaration.
80fd2569 350
a9b83695 351enum name : integer_type {
359894ac 352 somestring = start_value1 ... end_value1,
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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
359If the values are omitted, the enumeration starts at 0 and increment of 1 for
360each entry:
361
a9b83695 362enum name : unsigned int {
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363 ZERO,
364 ONE,
365 TWO,
366 TEN = 10,
367 ELEVEN,
3bf79539 368};
5ba9f198 369
80fd2569 370Overlapping ranges within a single enumeration are implementation defined.
5ba9f198 371
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372A nameless enumeration can be declared as a field type or as part of a typedef:
373
a9b83695 374enum : integer_type {
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375 ...
376}
377
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378Enumerations omitting the container type ": integer_type" use the "int"
379type (for compatibility with C99). The "int" type must be previously
380declared. E.g.:
381
382typealias integer { size = 32; align = 32; signed = true } := int;
383
384enum {
385 ...
386}
387
1fad7a85 388
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3894.2 Compound types
390
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391Compound are aggregation of type declarations. Compound types include
392structures, variant, arrays, sequences, and strings.
393
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3944.2.1 Structures
395
396Structures are aligned on the largest alignment required by basic types
397contained within the structure. (This follows the ISO/C standard for structures)
398
6672e9e1 399TSDL meta-data representation of a named structure:
5ba9f198 400
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401struct name {
402 field_type field_name;
403 field_type field_name;
404 ...
405};
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406
407Example:
408
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409struct example {
410 integer { /* Nameless type */
411 size = 16;
412 signed = true;
413 align = 16;
414 } first_field_name;
6672e9e1 415 uint64_t second_field_name; /* Named type declared in the meta-data */
3bf79539 416};
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417
418The fields are placed in a sequence next to each other. They each possess a
419field name, which is a unique identifier within the structure.
420
2152348f 421A nameless structure can be declared as a field type or as part of a typedef:
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422
423struct {
424 ...
2152348f 425}
80fd2569 426
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427Alignment for a structure compound type can be forced to a minimum value
428by adding an "align" specifier after the declaration of a structure
429body. This attribute is read as: align(value). The value is specified in
430bits. The structure will be aligned on the maximum value between this
431attribute and the alignment required by the basic types contained within
432the structure. e.g.
433
434struct {
435 ...
436} align(32)
437
77a98c82 4384.2.2 Variants (Discriminated/Tagged Unions)
fcba70d4 439
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440A CTF variant is a selection between different types. A CTF variant must
441always be defined within the scope of a structure or within fields
442contained within a structure (defined recursively). A "tag" enumeration
443field must appear in either the same lexical scope, prior to the variant
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444field (in field declaration order), in an upper lexical scope (see
445Section 7.3.1), or in an upper dynamic scope (see Section 7.3.2). The
446type selection is indicated by the mapping from the enumeration value to
447the string used as variant type selector. The field to use as tag is
448specified by the "tag_field", specified between "< >" after the
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449"variant" keyword for unnamed variants, and after "variant name" for
450named variants.
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451
452The alignment of the variant is the alignment of the type as selected by the tag
453value for the specific instance of the variant. The alignment of the type
454containing the variant is independent of the variant alignment. The size of the
455variant is the size as selected by the tag value for the specific instance of
456the variant.
457
458A named variant declaration followed by its definition within a structure
459declaration:
460
461variant name {
462 field_type sel1;
463 field_type sel2;
464 field_type sel3;
465 ...
466};
467
468struct {
a9b83695 469 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
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470 ...
471 variant name <tag_field> v;
472}
473
474An unnamed variant definition within a structure is expressed by the following
6672e9e1 475TSDL meta-data:
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476
477struct {
a9b83695 478 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
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479 ...
480 variant <tag_field> {
481 field_type sel1;
482 field_type sel2;
483 field_type sel3;
484 ...
485 } v;
486}
487
488Example of a named variant within a sequence that refers to a single tag field:
489
490variant example {
491 uint32_t a;
492 uint64_t b;
493 short c;
494};
495
496struct {
a9b83695 497 enum : uint2_t { a, b, c } choice;
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498 unsigned int seqlen;
499 variant example <choice> v[seqlen];
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500}
501
502Example of an unnamed variant:
503
504struct {
a9b83695 505 enum : uint2_t { a, b, c, d } choice;
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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
519Example of an unnamed variant within an array:
520
521struct {
a9b83695 522 enum : uint2_t { a, b, c } choice;
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523 variant <choice> {
524 uint32_t a;
525 uint64_t b;
526 short c;
15850440 527 } v[10];
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528}
529
530Example of a variant type definition within a structure, where the defined type
531is then declared within an array of structures. This variant refers to a tag
532located in an upper lexical scope. This example clearly shows that a variant
533type definition referring to the tag "x" uses the closest preceding field from
534the lexical scope of the type definition.
535
536struct {
a9b83695 537 enum : uint2_t { a, b, c, d } x;
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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 {
a9b83695 549 enum : int { x, y, z } x; /* This enumeration is not used by "v". */
fcba70d4 550 example_variant v; /*
a9b83695 551 * "v" uses the "enum : uint2_t { a, b, c, d }"
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552 * tag.
553 */
554 } a[10];
555}
556
5574.2.3 Arrays
5ba9f198 558
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559Arrays are fixed-length. Their length is declared in the type
560declaration within the meta-data. They contain an array of "inner type"
561elements, which can refer to any type not containing the type of the
562array being declared (no circular dependency). The length is the number
563of elements in an array.
5ba9f198 564
6672e9e1 565TSDL meta-data representation of a named array:
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566
567typedef elem_type name[length];
5ba9f198 568
2152348f 569A nameless array can be declared as a field type within a structure, e.g.:
5ba9f198 570
2152348f 571 uint8_t field_name[10];
80fd2569 572
ec4404a7 573Arrays are always aligned on their element alignment requirement.
5ba9f198 574
fcba70d4 5754.2.4 Sequences
5ba9f198 576
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577Sequences are dynamically-sized arrays. They refer to a a "length"
578unsigned integer field, which must appear in either the same lexical scope,
579prior to the sequence field (in field declaration order), in an upper
580lexical scope (see Section 7.3.1), or in an upper dynamic scope (see
581Section 7.3.2). This length field represents the number of elements in
582the sequence. The sequence per se is an array of "inner type" elements.
5ba9f198 583
1ab22b2a 584TSDL meta-data representation for a sequence type definition:
80fd2569 585
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586struct {
587 unsigned int length_field;
588 typedef elem_type typename[length_field];
589 typename seq_field_name;
590}
591
592A sequence can also be declared as a field type, e.g.:
80fd2569 593
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594struct {
595 unsigned int length_field;
596 long seq_field_name[length_field];
597}
80fd2569 598
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599Multiple sequences can refer to the same length field, and these length
600fields can be in a different upper dynamic scope:
601
602e.g., assuming the stream.event.header defines:
603
604stream {
605 ...
606 id = 1;
607 event.header := struct {
608 uint16_t seq_len;
609 };
610};
611
612event {
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};
80fd2569 620
1ab22b2a 621The sequence elements follow the "array" specifications.
5ba9f198 622
fcba70d4 6234.2.5 Strings
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624
625Strings are an array of bytes of variable size and are terminated by a '\0'
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626"NULL" character. Their encoding is described in the TSDL meta-data. In
627absence of encoding attribute information, the default encoding is
628UTF-8.
5ba9f198 629
6672e9e1 630TSDL meta-data representation of a named string type:
80fd2569 631
359894ac 632typealias string {
5ba9f198 633 encoding = UTF8 OR ASCII;
38b8da21 634} := name;
5ba9f198 635
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636A nameless string type can be declared as a field type:
637
638string field_name; /* Use default UTF8 encoding */
5ba9f198 639
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640Strings are always aligned on byte size.
641
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6425. Event Packet Header
643
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644The event packet header consists of two parts: the "event packet header"
645is the same for all streams of a trace. The second part, the "event
646packet context", is described on a per-stream basis. Both are described
647in the TSDL meta-data. The packets are aligned on architecture-page-sized
648addresses.
3bf79539 649
6672e9e1 650Event packet header (all fields are optional, specified by TSDL meta-data):
3bf79539 651
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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.
3bf79539 663
6672e9e1 664Event packet context (all fields are optional, specified by TSDL meta-data):
3bf79539 665
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666- Event packet content size (in bits).
667- Event packet size (in bits, includes padding).
cda89682 668- Event packet content checksum. Checksum excludes the event packet
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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
b11853af 672 wrap-arounds are dealt with correctly.
6672e9e1 673- Time-stamp at the beginning and time-stamp at the end of the event packet.
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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.
5ba9f198 678- Events discarded count
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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.
5ba9f198 682 * Note: producer-consumer buffer full condition should fill the current
3bf79539 683 event packet with padding so we know exactly where events have been
5ba9f198 684 discarded.
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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.
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688 0: no compression scheme
689 1: bzip2
690 2: gzip
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691 3: xz
692- Cypher used for the event packet content. Applied after compression.
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693 0: no encryption
694 1: AES
3bf79539 695- Checksum scheme used for the event packet content. Applied after encryption.
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696 0: no checksum
697 1: md5
698 2: sha1
699 3: crc32
700
6672e9e1 7015.1 Event Packet Header Description
3bf79539 702
fc5425db 703The event packet header layout is indicated by the trace packet.header
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704field. Here is a recommended structure type for the packet header with
705the fields typically expected (although these fields are each optional):
fc5425db 706
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707struct event_packet_header {
708 uint32_t magic;
3fde5da1 709 uint8_t uuid[16];
3bf79539 710 uint32_t stream_id;
80fd2569 711};
5ba9f198 712
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713trace {
714 ...
715 packet.header := struct event_packet_header;
716};
717
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718If the magic number is not present, tools such as "file" will have no
719mean to discover the file type.
720
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721If the uuid is not present, no validation that the meta-data actually
722corresponds to the stream is performed.
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723
724If the stream_id packet header field is missing, the trace can only
725contain a single stream. Its "id" field can be left out, and its events
726don't need to declare a "stream_id" field.
727
728
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7295.2 Event Packet Context Description
730
731Event packet context example. These are declared within the stream declaration
6672e9e1 732in the meta-data. All these fields are optional. If the packet size field is
6a7c61df 733missing, the whole stream only contains a single packet. If the content
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734size field is missing, the packet is filled (no padding). The content
735and packet sizes include all headers.
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736
737An example event packet context type:
738
80fd2569 739struct event_packet_context {
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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;
3b0f8e4d 751 uint8_t checksum_scheme;
3bf79539 752};
5ba9f198 753
fcba70d4 754
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7556. Event Structure
756
757The overall structure of an event is:
758
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7591 - 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)
5ba9f198 764
fdf2bb05 765This structure defines an implicit dynamic scoping, where variants
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766located in inner structures (those with a higher number in the listing
767above) can refer to the fields of outer structures (with lower number in
6c7226e9 768the listing above). See Section 7.3 TSDL Scopes for more detail.
5ba9f198 769
fdf2bb05 7706.1 Event Header
fcba70d4 771
6672e9e1 772Event headers can be described within the meta-data. We hereby propose, as an
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773example, two types of events headers. Type 1 accommodates streams with less than
77431 event IDs. Type 2 accommodates streams with 31 or more event IDs.
5ba9f198 775
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776One major factor can vary between streams: the number of event IDs assigned to
777a stream. Luckily, this information tends to stay relatively constant (modulo
5ba9f198 778event registration while trace is being recorded), so we can specify different
3bf79539 779representations for streams containing few event IDs and streams containing
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780many event IDs, so we end up representing the event ID and time-stamp as
781densely as possible in each case.
5ba9f198 782
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783The header is extended in the rare occasions where the information cannot be
784represented in the ranges available in the standard event header. They are also
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785used in the rare occasions where the data required for a field could not be
786collected: the flag corresponding to the missing field within the missing_fields
787array is then set to 1.
5ba9f198 788
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789Types uintX_t represent an X-bit unsigned integer, as declared with
790either:
5ba9f198 791
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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;
5ba9f198 797
fdf2bb05 7986.1.1 Type 1 - Few event IDs
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799
800 - Aligned on 32-bit (or 8-bit if byte-packed, depending on the architecture
801 preference).
5ba9f198 802 - Native architecture byte ordering.
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803 - For "compact" selection
804 - Fixed size: 32 bits.
805 - For "extended" selection
806 - Size depends on the architecture and variant alignment.
5ba9f198 807
80fd2569 808struct event_header_1 {
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809 /*
810 * id: range: 0 - 30.
811 * id 31 is reserved to indicate an extended header.
812 */
a9b83695 813 enum : uint5_t { compact = 0 ... 30, extended = 31 } id;
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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;
cb108fea 823} align(32); /* or align(8) */
5ba9f198 824
5ba9f198 825
fdf2bb05 8266.1.2 Type 2 - Many event IDs
5ba9f198 827
fcba70d4 828 - Aligned on 16-bit (or 8-bit if byte-packed, depending on the architecture
5ba9f198 829 preference).
5ba9f198 830 - Native architecture byte ordering.
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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.
5ba9f198 835
80fd2569 836struct event_header_2 {
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837 /*
838 * id: range: 0 - 65534.
839 * id 65535 is reserved to indicate an extended header.
840 */
a9b83695 841 enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;
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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;
cb108fea 851} align(16); /* or align(8) */
5ba9f198 852
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853
8546.2 Event Context
855
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856The event context contains information relative to the current event.
857The choice and meaning of this information is specified by the TSDL
858stream and event meta-data descriptions. The stream context is applied
859to all events within the stream. The stream context structure follows
860the event header. The event context is applied to specific events. Its
861structure follows the stream context structure.
5ba9f198 862
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863An example of stream-level event context is to save the event payload size with
864each event, or to save the current PID with each event. These are declared
6672e9e1 865within the stream declaration within the meta-data:
5ba9f198 866
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867 stream {
868 ...
6672e9e1 869 event.context := struct {
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870 uint pid;
871 uint16_t payload_size;
6672e9e1 872 };
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873 };
874
875An example of event-specific event context is to declare a bitmap of missing
876fields, only appended after the stream event context if the extended event
877header is selected. NR_FIELDS is the number of fields within the event (a
878numeric value).
5ba9f198 879
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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 }
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891
8926.3 Event Payload
893
894An event payload contains fields specific to a given event type. The fields
6672e9e1 895belonging to an event type are described in the event-specific meta-data
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896within a structure type.
897
8986.3.1 Padding
899
900No padding at the end of the event payload. This differs from the ISO/C standard
901for structures, but follows the CTF standard for structures. In a trace, even
902though it makes sense to align the beginning of a structure, it really makes no
903sense to add padding at the end of the structure, because structures are usually
904not followed by a structure of the same type.
905
906This trick can be done by adding a zero-length "end" field at the end of the C
907structures, and by using the offset of this field rather than using sizeof()
3bf79539 908when calculating the size of a structure (see Appendix "A. Helper macros").
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909
9106.3.2 Alignment
911
912The event payload is aligned on the largest alignment required by types
913contained within the payload. (This follows the ISO/C standard for structures)
914
915
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9167. Trace Stream Description Language (TSDL)
917
918The Trace Stream Description Language (TSDL) allows expression of the
919binary trace streams layout in a C99-like Domain Specific Language
920(DSL).
921
922
6672e9e1 9237.1 Meta-data
6c7226e9
MD
924
925The trace stream layout description is located in the trace meta-data.
926The meta-data is itself located in a stream identified by its name:
927"metadata".
5ba9f198 928
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929The meta-data description can be expressed in two different formats:
930text-only and packet-based. The text-only description facilitates
931generation of meta-data and provides a convenient way to enter the
932meta-data information by hand. The packet-based meta-data provides the
933CTF stream packet facilities (checksumming, compression, encryption,
934network-readiness) for meta-data stream generated and transported by a
935tracer.
936
937The text-only meta-data file is a plain text TSDL description.
938
939The packet-based meta-data is made of "meta-data packets", which each
940start with a meta-data packet header. The packet-based meta-data
941description is detected by reading the magic number "0x75D11D57" at the
942beginning of the file. This magic number is also used to detect the
943endianness of the architecture by trying to read the CTF magic number
944and its counterpart in reversed endianness. The events within the
945meta-data stream have no event header nor event context. Each event only
5ae2352d 946contains a "sequence" payload, which is a sequence of bits using the
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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
949sequence of bits is a plain-text representation of the TSDL description.
950Each meta-data packet start with a special packet header, specific to
951the meta-data stream, which contains, exactly:
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952
953struct metadata_packet_header {
2daeaa3a 954 uint32_t magic; /* 0x75D11D57 */
3fde5da1 955 uint8_t uuid[16]; /* Unique Universal Identifier */
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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
964The packet-based meta-data can be converted to a text-only meta-data by
965concatenating all the strings in contains.
4fafe1ad 966
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967In the textual representation of the meta-data, the text contained
968within "/*" and "*/", as well as within "//" and end of line, are
969treated as comments. Boolean values can be represented as true, TRUE,
970or 1 for true, and false, FALSE, or 0 for false. Within the string-based
971meta-data description, the trace UUID is represented as a string of
972hexadecimal digits and dashes "-". In the event packet header, the trace
973UUID is represented as an array of bytes.
fcba70d4 974
fdf2bb05 975
6c7226e9 9767.2 Declaration vs Definition
fdf2bb05
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977
978A declaration associates a layout to a type, without specifying where
979this type is located in the event structure hierarchy (see Section 6).
980This therefore includes typedef, typealias, as well as all type
981specifiers. In certain circumstances (typedef, structure field and
982variant field), a declaration is followed by a declarator, which specify
983the newly defined type name (for typedef), or the field name (for
984declarations located within structure and variants). Array and sequence,
985declared with square brackets ("[" "]"), are part of the declarator,
a9b83695 986similarly to C99. The enumeration base type is specified by
6c7226e9 987": enum_base", which is part of the type specifier. The variant tag
a9b83695 988name, specified between "<" ">", is also part of the type specifier.
fdf2bb05
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989
990A definition associates a type to a location in the event structure
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991hierarchy (see Section 6). This association is denoted by ":=", as shown
992in Section 7.3.
fdf2bb05
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993
994
6c7226e9 9957.3 TSDL Scopes
fdf2bb05 996
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997TSDL uses two different types of scoping: a lexical scope is used for
998declarations and type definitions, and a dynamic scope is used for
2e7d7fcb
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999variants references to tag fields and for sequence references to length
1000fields.
fdf2bb05 1001
6c7226e9 10027.3.1 Lexical Scope
fdf2bb05 1003
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1004Each of "trace", "stream", "event", "struct" and "variant" have their own
1005nestable declaration scope, within which types can be declared using "typedef"
fdf2bb05 1006and "typealias". A root declaration scope also contains all declarations
7d9d7e92 1007located outside of any of the aforementioned declarations. An inner
fdf2bb05 1008declaration scope can refer to type declared within its container
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1009lexical scope prior to the inner declaration scope. Redefinition of a
1010typedef or typealias is not valid, although hiding an upper scope
fdf2bb05
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1011typedef or typealias is allowed within a sub-scope.
1012
6c7226e9 10137.3.2 Dynamic Scope
fdf2bb05 1014
7d9d7e92
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1015A dynamic scope consists in the lexical scope augmented with the
1016implicit event structure definition hierarchy presented at Section 6.
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1017The dynamic scope is used for variant tag and sequence length
1018definitions. It is used at definition time to look up the location of
1019the tag field associated with a variant, and to lookup up the location
1020of the length field associated with a sequence.
1021
1022Therefore, 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
1024upper levels (e.g. in the event header) by specifying, in this case, the
1025associated tag with <header.field_name>. This allows, for instance, the
1026event context to define a variant referring to the "id" field of the
1027event header as selector.
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1028
1029The target dynamic scope must be specified explicitly when referring to
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1030a field outside of the local static scope (a local static scope contains
1031all fields present within the same scope, at the same nesting level).
1032The dynamic scope prefixes are thus:
fdf2bb05 1033
e0d9e2c7 1034 - Trace Packet Header: <trace.packet.header. >,
7d9d7e92
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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. >.
fdf2bb05
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1040
1041Multiple declarations of the same field name within a single scope is
1042not valid. It is however valid to re-use the same field name in
1043different scopes. There is no possible conflict, because the dynamic
1044scope must be specified when a variant refers to a tag field located in
1045a different dynamic scope.
1046
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1047The information available in the dynamic scopes can be thought of as the
1048current tracing context. At trace production, information about the
1049current context is saved into the specified scope field levels. At trace
1050consumption, for each event, the current trace context is therefore
1051readable by accessing the upper dynamic scopes.
1052
fdf2bb05 1053
6c7226e9 10547.4 TSDL Examples
d285084f 1055
6672e9e1 1056The grammar representing the TSDL meta-data is presented in Appendix C.
7df6b93a 1057TSDL Grammar. This section presents a rather lighter reading that
6672e9e1 1058consists in examples of TSDL meta-data, with template values.
969f30c0 1059
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1060The stream "id" can be left out if there is only one stream in the
1061trace. The event "id" field can be left out if there is only one event
1062in a stream.
1063
5ba9f198 1064trace {
fdf2bb05 1065 major = value; /* Trace format version */
5ba9f198 1066 minor = value;
fdf2bb05 1067 uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"; /* Trace UUID */
58997e9e 1068 byte_order = be OR le; /* Endianness (required) */
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1069 packet.header := struct {
1070 uint32_t magic;
3fde5da1 1071 uint8_t uuid[16];
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1072 uint32_t stream_id;
1073 };
3bf79539 1074};
5ba9f198 1075
3bf79539
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1076stream {
1077 id = stream_id;
fdf2bb05 1078 /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */
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1079 event.header := event_header_1 OR event_header_2;
1080 event.context := struct {
77a98c82 1081 ...
3bf79539 1082 };
4fa992a5 1083 packet.context := struct {
77a98c82 1084 ...
3bf79539
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1085 };
1086};
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1087
1088event {
3d13ef1a 1089 name = event_name;
3bf79539 1090 id = value; /* Numeric identifier within the stream */
67f02e24 1091 stream_id = stream_id;
4fa992a5 1092 context := struct {
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1093 ...
1094 };
4fa992a5 1095 fields := struct {
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1096 ...
1097 };
3bf79539 1098};
5ba9f198
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1099
1100/* More detail on types in section 4. Types */
1101
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1102/*
1103 * Named types:
1104 *
4fa992a5 1105 * Type declarations behave similarly to the C standard.
3d13ef1a
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1106 */
1107
80af8ac6 1108typedef aliased_type_specifiers new_type_declarators;
2152348f 1109
3d13ef1a 1110/* e.g.: typedef struct example new_type_name[10]; */
80fd2569 1111
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1112/*
1113 * typealias
1114 *
1115 * The "typealias" declaration can be used to give a name (including
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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
38b8da21 1119 * simple variable identifier to a type.
4fa992a5
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1120 */
1121
1122typealias type_class {
80fd2569 1123 ...
38b8da21 1124} := type_specifiers type_declarator;
2152348f 1125
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1126/*
1127 * e.g.:
4fa992a5 1128 * typealias integer {
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MD
1129 * size = 32;
1130 * align = 32;
1131 * signed = false;
38b8da21 1132 * } := struct page *;
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1133 *
1134 * typealias integer {
1135 * size = 32;
1136 * align = 32;
1137 * signed = true;
38b8da21 1138 * } := int;
3d13ef1a 1139 */
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1140
1141struct name {
3bf79539
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1142 ...
1143};
5ba9f198 1144
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1145variant name {
1146 ...
1147};
1148
a9b83695 1149enum name : integer_type {
3bf79539
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1150 ...
1151};
1152
2152348f 1153
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1154/*
1155 * Unnamed types, contained within compound type fields, typedef or typealias.
1156 */
2152348f 1157
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1158struct {
1159 ...
2152348f 1160}
5ba9f198 1161
ec4404a7
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1162struct {
1163 ...
1164} align(value)
1165
fcba70d4
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1166variant {
1167 ...
1168}
1169
a9b83695 1170enum : integer_type {
80fd2569 1171 ...
2152348f
MD
1172}
1173
1174typedef type new_type[length];
3bf79539 1175
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1176struct {
1177 type field_name[length];
1178}
1179
1180typedef type new_type[length_type];
1181
1182struct {
1183 type field_name[length_type];
1184}
1185
1186integer {
80fd2569 1187 ...
2152348f 1188}
3bf79539 1189
2152348f 1190floating_point {
80fd2569 1191 ...
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MD
1192}
1193
1194struct {
1195 integer_type field_name:size; /* GNU/C bitfield */
1196}
1197
1198struct {
1199 string field_name;
1200}
3bf79539 1201
fcba70d4 1202
3bf79539 1203A. Helper macros
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1204
1205The two following macros keep track of the size of a GNU/C structure without
1206padding at the end by placing HEADER_END as the last field. A one byte end field
1207is used for C90 compatibility (C99 flexible arrays could be used here). Note
1208that this does not affect the effective structure size, which should always be
1209calculated with the header_sizeof() helper.
1210
1211#define HEADER_END char end_field
1212#define header_sizeof(type) offsetof(typeof(type), end_field)
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1213
1214
1215B. Stream Header Rationale
1216
1217An event stream is divided in contiguous event packets of variable size. These
1218subdivisions allow the trace analyzer to perform a fast binary search by time
1219within the stream (typically requiring to index only the event packet headers)
1220without reading the whole stream. These subdivisions have a variable size to
1221eliminate the need to transfer the event packet padding when partially filled
1222event packets must be sent when streaming a trace for live viewing/analysis.
1223An event packet can contain a certain amount of padding at the end. Dividing
1224streams into event packets is also useful for network streaming over UDP and
1225flight recorder mode tracing (a whole event packet can be swapped out of the
1226buffer atomically for reading).
1227
1228The stream header is repeated at the beginning of each event packet to allow
1229flexibility 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
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1239
1240C. TSDL Grammar
fcba70d4 1241
4fa992a5 1242/*
6c7226e9 1243 * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar.
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1244 *
1245 * Inspired from the C99 grammar:
1246 * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A)
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1247 * and c++1x grammar (draft)
1248 * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A)
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1249 *
1250 * Specialized for CTF needs by including only constant and declarations from
1251 * C99 (excluding function declarations), and by adding support for variants,
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1252 * sequences and CTF-specific specifiers. Enumeration container types
1253 * semantic is inspired from c++1x enum-base.
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1254 */
1255
12561) Lexical grammar
1257
12581.1) Lexical elements
1259
1260token:
1261 keyword
1262 identifier
1263 constant
1264 string-literal
1265 punctuator
1266
12671.2) Keywords
1268
1269keyword: is one of
1270
ec4404a7 1271align
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1272const
1273char
1274double
1275enum
1276event
1277floating_point
1278float
1279integer
1280int
1281long
1282short
1283signed
1284stream
1285string
1286struct
1287trace
3e1e1a78 1288typealias
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1289typedef
1290unsigned
1291variant
1292void
1293_Bool
1294_Complex
1295_Imaginary
1296
1297
12981.3) Identifiers
1299
1300identifier:
1301 identifier-nondigit
1302 identifier identifier-nondigit
1303 identifier digit
1304
1305identifier-nondigit:
1306 nondigit
1307 universal-character-name
1308 any other implementation-defined characters
1309
1310nondigit:
1311 _
1312 [a-zA-Z] /* regular expression */
1313
1314digit:
1315 [0-9] /* regular expression */
1316
13171.4) Universal character names
1318
1319universal-character-name:
1320 \u hex-quad
1321 \U hex-quad hex-quad
1322
1323hex-quad:
1324 hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit
1325
13261.5) Constants
1327
1328constant:
1329 integer-constant
1330 enumeration-constant
1331 character-constant
1332
1333integer-constant:
1334 decimal-constant integer-suffix-opt
1335 octal-constant integer-suffix-opt
1336 hexadecimal-constant integer-suffix-opt
1337
1338decimal-constant:
1339 nonzero-digit
1340 decimal-constant digit
1341
1342octal-constant:
1343 0
1344 octal-constant octal-digit
1345
1346hexadecimal-constant:
1347 hexadecimal-prefix hexadecimal-digit
1348 hexadecimal-constant hexadecimal-digit
1349
1350hexadecimal-prefix:
1351 0x
1352 0X
1353
1354nonzero-digit:
1355 [1-9]
1356
1357integer-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
1363unsigned-suffix:
1364 u
1365 U
1366
1367long-suffix:
1368 l
1369 L
1370
1371long-long-suffix:
1372 ll
1373 LL
1374
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1375enumeration-constant:
1376 identifier
1377 string-literal
1378
1379character-constant:
1380 ' c-char-sequence '
1381 L' c-char-sequence '
1382
1383c-char-sequence:
1384 c-char
1385 c-char-sequence c-char
1386
1387c-char:
1388 any member of source charset except single-quote ('), backslash
1389 (\), or new-line character.
1390 escape-sequence
1391
1392escape-sequence:
1393 simple-escape-sequence
1394 octal-escape-sequence
1395 hexadecimal-escape-sequence
1396 universal-character-name
1397
1398simple-escape-sequence: one of
1399 \' \" \? \\ \a \b \f \n \r \t \v
1400
1401octal-escape-sequence:
1402 \ octal-digit
1403 \ octal-digit octal-digit
1404 \ octal-digit octal-digit octal-digit
1405
1406hexadecimal-escape-sequence:
1407 \x hexadecimal-digit
1408 hexadecimal-escape-sequence hexadecimal-digit
1409
14101.6) String literals
1411
1412string-literal:
1413 " s-char-sequence-opt "
1414 L" s-char-sequence-opt "
1415
1416s-char-sequence:
1417 s-char
1418 s-char-sequence s-char
1419
1420s-char:
1421 any member of source charset except double-quote ("), backslash
1422 (\), or new-line character.
1423 escape-sequence
1424
14251.7) Punctuators
1426
1427punctuator: one of
1428 [ ] ( ) { } . -> * + - < > : ; ... = ,
1429
1430
14312) Phrase structure grammar
1432
1433primary-expression:
1434 identifier
1435 constant
1436 string-literal
1437 ( unary-expression )
1438
1439postfix-expression:
1440 primary-expression
1441 postfix-expression [ unary-expression ]
1442 postfix-expression . identifier
1443 postfix-expressoin -> identifier
1444
1445unary-expression:
1446 postfix-expression
1447 unary-operator postfix-expression
1448
1449unary-operator: one of
1450 + -
1451
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1452assignment-operator:
1453 =
1454
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1455type-assignment-operator:
1456 :=
1457
4fa992a5 1458constant-expression-range:
73d61ac3 1459 unary-expression ... unary-expression
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1460
14612.2) Declarations:
1462
1463declaration:
689e04b4 1464 declaration-specifiers declarator-list-opt ;
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1465 ctf-specifier ;
1466
1467declaration-specifiers:
689e04b4 1468 storage-class-specifier declaration-specifiers-opt
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1469 type-specifier declaration-specifiers-opt
1470 type-qualifier declaration-specifiers-opt
1471
1472declarator-list:
1473 declarator
1474 declarator-list , declarator
1475
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1476abstract-declarator-list:
1477 abstract-declarator
1478 abstract-declarator-list , abstract-declarator
1479
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1480storage-class-specifier:
1481 typedef
1482
1483type-specifier:
1484 void
1485 char
1486 short
1487 int
1488 long
1489 float
1490 double
1491 signed
1492 unsigned
1493 _Bool
1494 _Complex
cfdd51ec 1495 _Imaginary
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1496 struct-specifier
1497 variant-specifier
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1498 enum-specifier
1499 typedef-name
1500 ctf-type-specifier
1501
ec4404a7 1502align-attribute:
73d61ac3 1503 align ( unary-expression )
ec4404a7 1504
4fa992a5 1505struct-specifier:
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1506 struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
1507 struct identifier align-attribute-opt
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1508
1509struct-or-variant-declaration-list:
1510 struct-or-variant-declaration
1511 struct-or-variant-declaration-list struct-or-variant-declaration
1512
1513struct-or-variant-declaration:
1514 specifier-qualifier-list struct-or-variant-declarator-list ;
eacb16d1 1515 declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt declarator-list ;
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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 ;
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1518
1519specifier-qualifier-list:
1520 type-specifier specifier-qualifier-list-opt
1521 type-qualifier specifier-qualifier-list-opt
1522
1523struct-or-variant-declarator-list:
1524 struct-or-variant-declarator
1525 struct-or-variant-declarator-list , struct-or-variant-declarator
1526
1527struct-or-variant-declarator:
1528 declarator
73d61ac3 1529 declarator-opt : unary-expression
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1530
1531variant-specifier:
1532 variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
1533 variant identifier variant-tag
1534
1535variant-tag:
1536 < identifier >
1537
1538enum-specifier:
1539 enum identifier-opt { enumerator-list }
1540 enum identifier-opt { enumerator-list , }
1541 enum identifier
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1542 enum identifier-opt : declaration-specifiers { enumerator-list }
1543 enum identifier-opt : declaration-specifiers { enumerator-list , }
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1544
1545enumerator-list:
1546 enumerator
1547 enumerator-list , enumerator
1548
1549enumerator:
1550 enumeration-constant
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1551 enumeration-constant assignment-operator unary-expression
1552 enumeration-constant assignment-operator constant-expression-range
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1553
1554type-qualifier:
1555 const
1556
1557declarator:
1558 pointer-opt direct-declarator
1559
1560direct-declarator:
1561 identifier
1562 ( declarator )
1ab22b2a 1563 direct-declarator [ unary-expression ]
4fa992a5 1564
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1565abstract-declarator:
1566 pointer-opt direct-abstract-declarator
1567
1568direct-abstract-declarator:
1569 identifier-opt
1570 ( abstract-declarator )
1ab22b2a 1571 direct-abstract-declarator [ unary-expression ]
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1572 direct-abstract-declarator [ ]
1573
4fa992a5 1574pointer:
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1575 * type-qualifier-list-opt
1576 * type-qualifier-list-opt pointer
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1577
1578type-qualifier-list:
1579 type-qualifier
1580 type-qualifier-list type-qualifier
1581
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1582typedef-name:
1583 identifier
1584
15852.3) CTF-specific declarations
1586
1587ctf-specifier:
1588 event { ctf-assignment-expression-list-opt }
1589 stream { ctf-assignment-expression-list-opt }
1590 trace { ctf-assignment-expression-list-opt }
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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
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1593
1594ctf-type-specifier:
1595 floating_point { ctf-assignment-expression-list-opt }
1596 integer { ctf-assignment-expression-list-opt }
1597 string { ctf-assignment-expression-list-opt }
7609d3c7 1598 string
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1599
1600ctf-assignment-expression-list:
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1601 ctf-assignment-expression ;
1602 ctf-assignment-expression-list ctf-assignment-expression ;
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1603
1604ctf-assignment-expression:
1605 unary-expression assignment-operator unary-expression
1606 unary-expression type-assignment-operator type-specifier
eacb16d1 1607 declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt declarator-list
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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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