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5ba9f198 1
4767a9e7 2RFC: Common Trace Format (CTF) Proposal (pre-v1.7)
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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
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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.
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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
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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
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27Table of Contents
28
291. Preliminary definitions
302. High-level representation of a trace
313. Event stream
324. Types
33 4.1 Basic types
34 4.1.1 Type inheritance
35 4.1.2 Alignment
36 4.1.3 Byte order
37 4.1.4 Size
38 4.1.5 Integers
39 4.1.6 GNU/C bitfields
40 4.1.7 Floating point
41 4.1.8 Enumerations
424.2 Compound types
43 4.2.1 Structures
44 4.2.2 Variants (Discriminated/Tagged Unions)
45 4.2.3 Arrays
46 4.2.4 Sequences
47 4.2.5 Strings
485. Event Packet Header
49 5.1 Event Packet Header Description
50 5.2 Event Packet Context Description
516. Event Structure
52 6.1 Event Header
53 6.1.1 Type 1 - Few event IDs
54 6.1.2 Type 2 - Many event IDs
55 6.2 Event Context
56 6.3 Event Payload
57 6.3.1 Padding
58 6.3.2 Alignment
597. Trace Stream Description Language (TSDL)
60 7.1 Meta-data
61 7.2 Declaration vs Definition
62 7.3 TSDL Scopes
63 7.3.1 Lexical Scope
64 7.3.2 Dynamic Scope
65 7.4 TSDL Examples
66
67
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681. Preliminary definitions
69
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70 - Event Trace: An ordered sequence of events.
71 - Event Stream: An ordered sequence of events, containing a subset of the
72 trace event types.
73 - Event Packet: A sequence of physically contiguous events within an event
74 stream.
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75 - Event: This is the basic entry in a trace. (aka: a trace record).
76 - An event identifier (ID) relates to the class (a type) of event within
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77 an event stream.
78 e.g. event: irq_entry.
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79 - An event (or event record) relates to a specific instance of an event
80 class.
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81 e.g. event: irq_entry, at time X, on CPU Y
82 - Source Architecture: Architecture writing the trace.
83 - Reader Architecture: Architecture reading the trace.
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84
85
862. High-level representation of a trace
87
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88A trace is divided into multiple event streams. Each event stream contains a
89subset of the trace event types.
5ba9f198 90
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91The final output of the trace, after its generation and optional transport over
92the network, is expected to be either on permanent or temporary storage in a
93virtual file system. Because each event stream is appended to while a trace is
94being recorded, each is associated with a separate file for output. Therefore,
95a stored trace can be represented as a directory containing one file per stream.
5ba9f198 96
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97Meta-data description associated with the trace contains information on
98trace event types expressed in the Trace Stream Description Language
99(TSDL). This language describes:
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100
101- Trace version.
102- Types available.
6672e9e1 103- Per-trace event header description.
3bf79539 104- Per-stream event header description.
6672e9e1 105- Per-stream event context description.
5ba9f198 106- Per-event
3bf79539 107 - Event type to stream mapping.
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108 - Event type to name mapping.
109 - Event type to ID mapping.
6672e9e1 110 - Event context description.
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111 - Event fields description.
112
113
3bf79539 1143. Event stream
5ba9f198 115
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116An event stream can be divided into contiguous event packets of variable
117size. These subdivisions have a variable size. An event packet can
118contain a certain amount of padding at the end. The stream header is
119repeated at the beginning of each event packet. The rationale for the
120event stream design choices is explained in Appendix B. Stream Header
121Rationale.
5ba9f198 122
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123The event stream header will therefore be referred to as the "event packet
124header" throughout the rest of this document.
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125
126
1274. Types
128
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129Types are organized as type classes. Each type class belong to either of two
130kind of types: basic types or compound types.
131
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1324.1 Basic types
133
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134A basic type is a scalar type, as described in this section. It includes
135integers, GNU/C bitfields, enumerations, and floating point values.
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136
1374.1.1 Type inheritance
138
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139Type specifications can be inherited to allow deriving types from a
140type class. For example, see the uint32_t named type derived from the "integer"
141type class below ("Integers" section). Types have a precise binary
142representation in the trace. A type class has methods to read and write these
143types, but must be derived into a type to be usable in an event field.
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144
1454.1.2 Alignment
146
147We define "byte-packed" types as aligned on the byte size, namely 8-bit.
148We define "bit-packed" types as following on the next bit, as defined by the
370eae99 149"Integers" section.
5ba9f198 150
6672e9e1 151Each basic type must specify its alignment, in bits. Examples of
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152possible alignments are: bit-packed (align = 1), byte-packed (align =
1538), or word-aligned (e.g. align = 32 or align = 64). The choice depends
154on the architecture preference and compactness vs performance trade-offs
155of the implementation. Architectures providing fast unaligned write
156byte-packed basic types to save space, aligning each type on byte
157boundaries (8-bit). Architectures with slow unaligned writes align types
158on specific alignment values. If no specific alignment is declared for a
159type, it is assumed to be bit-packed for integers with size not multiple
160of 8 bits and for gcc bitfields. All other basic types are byte-packed
161by default. It is however recommended to always specify the alignment
162explicitly. Alignment values must be power of two. Compound types are
163aligned as specified in their individual specification.
5ba9f198 164
6672e9e1 165TSDL meta-data attribute representation of a specific alignment:
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166
167 align = value; /* value in bits */
168
1694.1.3 Byte order
170
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171By default, the native endianness of the source architecture the trace is used.
172Byte order can be overridden for a basic type by specifying a "byte_order"
173attribute. Typical use-case is to specify the network byte order (big endian:
174"be") to save data captured from the network into the trace without conversion.
175If not specified, the byte order is native.
5ba9f198 176
6672e9e1 177TSDL meta-data representation:
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178
179 byte_order = native OR network OR be OR le; /* network and be are aliases */
180
1814.1.4 Size
182
183Type size, in bits, for integers and floats is that returned by "sizeof()" in C
184multiplied by CHAR_BIT.
185We require the size of "char" and "unsigned char" types (CHAR_BIT) to be fixed
186to 8 bits for cross-endianness compatibility.
187
6672e9e1 188TSDL meta-data representation:
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189
190 size = value; (value is in bits)
191
1924.1.5 Integers
193
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194Signed integers are represented in two-complement. Integer alignment,
195size, signedness and byte ordering are defined in the TSDL meta-data.
196Integers aligned on byte size (8-bit) and with length multiple of byte
197size (8-bit) correspond to the C99 standard integers. In addition,
198integers with alignment and/or size that are _not_ a multiple of the
199byte size are permitted; these correspond to the C99 standard bitfields,
200with the added specification that the CTF integer bitfields have a fixed
201binary representation. A MIT-licensed reference implementation of the
202CTF portable bitfields is available at:
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203
204 http://git.efficios.com/?p=babeltrace.git;a=blob;f=include/babeltrace/bitfield.h
205
206Binary representation of integers:
207
208- On little and big endian:
209 - Within a byte, high bits correspond to an integer high bits, and low bits
210 correspond to low bits.
211- On little endian:
212 - Integer across multiple bytes are placed from the less significant to the
213 most significant.
214 - Consecutive integers are placed from lower bits to higher bits (even within
215 a byte).
216- On big endian:
217 - Integer across multiple bytes are placed from the most significant to the
218 less significant.
219 - Consecutive integers are placed from higher bits to lower bits (even within
220 a byte).
221
222This binary representation is derived from the bitfield implementation in GCC
223for little and big endian. However, contrary to what GCC does, integers can
6672e9e1 224cross units boundaries (no padding is required). Padding can be explicitly
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225added (see 4.1.6 GNU/C bitfields) to follow the GCC layout if needed.
226
6672e9e1 227TSDL meta-data representation:
5ba9f198 228
80fd2569 229 integer {
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230 signed = true OR false; /* default false */
231 byte_order = native OR network OR be OR le; /* default native */
232 size = value; /* value in bits, no default */
233 align = value; /* value in bits */
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234 /* based used for pretty-printing output, default: decimal. */
235 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
236 OR octal OR oct OR o OR 8 OR binary OR b OR 2;
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237 /* character encoding, default: none */
238 encoding = none or UTF8 or ASCII;
2152348f 239 }
5ba9f198 240
80fd2569 241Example of type inheritance (creation of a uint32_t named type):
5ba9f198 242
359894ac 243typealias integer {
9e4e34e9 244 size = 32;
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245 signed = false;
246 align = 32;
38b8da21 247} := uint32_t;
5ba9f198 248
80fd2569 249Definition of a named 5-bit signed bitfield:
5ba9f198 250
359894ac 251typealias integer {
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252 size = 5;
253 signed = true;
254 align = 1;
38b8da21 255} := int5_t;
5ba9f198 256
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257The character encoding field can be used to specify that the integer
258must be printed as a text character when read. e.g.:
259
260typealias integer {
261 size = 8;
262 align = 8;
263 signed = false;
264 encoding = UTF8;
265} := utf_char;
266
267
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2684.1.6 GNU/C bitfields
269
270The GNU/C bitfields follow closely the integer representation, with a
271particularity on alignment: if a bitfield cannot fit in the current unit, the
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272unit is padded and the bitfield starts at the following unit. The unit size is
273defined by the size of the type "unit_type".
5ba9f198 274
6672e9e1 275TSDL meta-data representation:
80fd2569 276
d674f4b8 277 unit_type name:size;
80fd2569 278
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279As an example, the following structure declared in C compiled by GCC:
280
281struct example {
282 short a:12;
283 short b:5;
284};
285
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286The example structure is aligned on the largest element (short). The second
287bitfield would be aligned on the next unit boundary, because it would not fit in
288the current unit.
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289
2904.1.7 Floating point
291
6672e9e1 292The floating point values byte ordering is defined in the TSDL meta-data.
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293
294Floating point values follow the IEEE 754-2008 standard interchange formats.
295Description of the floating point values include the exponent and mantissa size
296in bits. Some requirements are imposed on the floating point values:
297
298- FLT_RADIX must be 2.
299- mant_dig is the number of digits represented in the mantissa. It is specified
300 by the ISO C99 standard, section 5.2.4, as FLT_MANT_DIG, DBL_MANT_DIG and
301 LDBL_MANT_DIG as defined by <float.h>.
302- exp_dig is the number of digits represented in the exponent. Given that
303 mant_dig is one bit more than its actual size in bits (leading 1 is not
304 needed) and also given that the sign bit always takes one bit, exp_dig can be
305 specified as:
306
307 - sizeof(float) * CHAR_BIT - FLT_MANT_DIG
308 - sizeof(double) * CHAR_BIT - DBL_MANT_DIG
309 - sizeof(long double) * CHAR_BIT - LDBL_MANT_DIG
310
6672e9e1 311TSDL meta-data representation:
5ba9f198 312
80fd2569 313floating_point {
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314 exp_dig = value;
315 mant_dig = value;
316 byte_order = native OR network OR be OR le;
317 align = value;
2152348f 318}
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319
320Example of type inheritance:
321
359894ac 322typealias floating_point {
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323 exp_dig = 8; /* sizeof(float) * CHAR_BIT - FLT_MANT_DIG */
324 mant_dig = 24; /* FLT_MANT_DIG */
325 byte_order = native;
ec4404a7 326 align = 32;
38b8da21 327} := float;
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328
329TODO: define NaN, +inf, -inf behavior.
330
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331Bit-packed, byte-packed or larger alignments can be used for floating
332point values, similarly to integers.
333
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3344.1.8 Enumerations
335
336Enumerations are a mapping between an integer type and a table of strings. The
337numerical representation of the enumeration follows the integer type specified
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338by the meta-data. The enumeration mapping table is detailed in the enumeration
339description within the meta-data. The mapping table maps inclusive value
340ranges (or single values) to strings. Instead of being limited to simple
3bf79539 341"value -> string" mappings, these enumerations map
80fd2569 342"[ start_value ... end_value ] -> string", which map inclusive ranges of
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343values to strings. An enumeration from the C language can be represented in
344this format by having the same start_value and end_value for each element, which
345is in fact a range of size 1. This single-value range is supported without
4767a9e7 346repeating the start and end values with the value = string declaration.
80fd2569 347
a9b83695 348enum name : integer_type {
359894ac 349 somestring = start_value1 ... end_value1,
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350 "other string" = start_value2 ... end_value2,
351 yet_another_string, /* will be assigned to end_value2 + 1 */
352 "some other string" = value,
353 ...
354};
355
356If the values are omitted, the enumeration starts at 0 and increment of 1 for
357each entry:
358
a9b83695 359enum name : unsigned int {
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360 ZERO,
361 ONE,
362 TWO,
363 TEN = 10,
364 ELEVEN,
3bf79539 365};
5ba9f198 366
80fd2569 367Overlapping ranges within a single enumeration are implementation defined.
5ba9f198 368
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369A nameless enumeration can be declared as a field type or as part of a typedef:
370
a9b83695 371enum : integer_type {
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372 ...
373}
374
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375Enumerations omitting the container type ": integer_type" use the "int"
376type (for compatibility with C99). The "int" type must be previously
377declared. E.g.:
378
379typealias integer { size = 32; align = 32; signed = true } := int;
380
381enum {
382 ...
383}
384
1fad7a85 385
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3864.2 Compound types
387
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388Compound are aggregation of type declarations. Compound types include
389structures, variant, arrays, sequences, and strings.
390
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3914.2.1 Structures
392
393Structures are aligned on the largest alignment required by basic types
394contained within the structure. (This follows the ISO/C standard for structures)
395
6672e9e1 396TSDL meta-data representation of a named structure:
5ba9f198 397
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398struct name {
399 field_type field_name;
400 field_type field_name;
401 ...
402};
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403
404Example:
405
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406struct example {
407 integer { /* Nameless type */
408 size = 16;
409 signed = true;
410 align = 16;
411 } first_field_name;
6672e9e1 412 uint64_t second_field_name; /* Named type declared in the meta-data */
3bf79539 413};
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414
415The fields are placed in a sequence next to each other. They each possess a
416field name, which is a unique identifier within the structure.
417
2152348f 418A nameless structure can be declared as a field type or as part of a typedef:
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419
420struct {
421 ...
2152348f 422}
80fd2569 423
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424Alignment for a structure compound type can be forced to a minimum value
425by adding an "align" specifier after the declaration of a structure
426body. This attribute is read as: align(value). The value is specified in
427bits. The structure will be aligned on the maximum value between this
428attribute and the alignment required by the basic types contained within
429the structure. e.g.
430
431struct {
432 ...
433} align(32)
434
77a98c82 4354.2.2 Variants (Discriminated/Tagged Unions)
fcba70d4 436
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437A CTF variant is a selection between different types. A CTF variant must
438always be defined within the scope of a structure or within fields
439contained within a structure (defined recursively). A "tag" enumeration
440field must appear in either the same lexical scope, prior to the variant
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441field (in field declaration order), in an upper lexical scope (see
442Section 7.3.1), or in an upper dynamic scope (see Section 7.3.2). The
443type selection is indicated by the mapping from the enumeration value to
444the string used as variant type selector. The field to use as tag is
445specified by the "tag_field", specified between "< >" after the
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446"variant" keyword for unnamed variants, and after "variant name" for
447named variants.
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448
449The alignment of the variant is the alignment of the type as selected by the tag
450value for the specific instance of the variant. The alignment of the type
451containing the variant is independent of the variant alignment. The size of the
452variant is the size as selected by the tag value for the specific instance of
453the variant.
454
455A named variant declaration followed by its definition within a structure
456declaration:
457
458variant name {
459 field_type sel1;
460 field_type sel2;
461 field_type sel3;
462 ...
463};
464
465struct {
a9b83695 466 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
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467 ...
468 variant name <tag_field> v;
469}
470
471An unnamed variant definition within a structure is expressed by the following
6672e9e1 472TSDL meta-data:
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473
474struct {
a9b83695 475 enum : integer_type { sel1, sel2, sel3, ... } tag_field;
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476 ...
477 variant <tag_field> {
478 field_type sel1;
479 field_type sel2;
480 field_type sel3;
481 ...
482 } v;
483}
484
485Example of a named variant within a sequence that refers to a single tag field:
486
487variant example {
488 uint32_t a;
489 uint64_t b;
490 short c;
491};
492
493struct {
a9b83695 494 enum : uint2_t { a, b, c } choice;
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495 unsigned int seqlen;
496 variant example <choice> v[seqlen];
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497}
498
499Example of an unnamed variant:
500
501struct {
a9b83695 502 enum : uint2_t { a, b, c, d } choice;
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503 /* Unrelated fields can be added between the variant and its tag */
504 int32_t somevalue;
505 variant <choice> {
506 uint32_t a;
507 uint64_t b;
508 short c;
509 struct {
510 unsigned int field1;
511 uint64_t field2;
512 } d;
513 } s;
514}
515
516Example of an unnamed variant within an array:
517
518struct {
a9b83695 519 enum : uint2_t { a, b, c } choice;
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520 variant <choice> {
521 uint32_t a;
522 uint64_t b;
523 short c;
15850440 524 } v[10];
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525}
526
527Example of a variant type definition within a structure, where the defined type
528is then declared within an array of structures. This variant refers to a tag
529located in an upper lexical scope. This example clearly shows that a variant
530type definition referring to the tag "x" uses the closest preceding field from
531the lexical scope of the type definition.
532
533struct {
a9b83695 534 enum : uint2_t { a, b, c, d } x;
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535
536 typedef variant <x> { /*
537 * "x" refers to the preceding "x" enumeration in the
538 * lexical scope of the type definition.
539 */
540 uint32_t a;
541 uint64_t b;
542 short c;
543 } example_variant;
544
545 struct {
a9b83695 546 enum : int { x, y, z } x; /* This enumeration is not used by "v". */
fcba70d4 547 example_variant v; /*
a9b83695 548 * "v" uses the "enum : uint2_t { a, b, c, d }"
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549 * tag.
550 */
551 } a[10];
552}
553
5544.2.3 Arrays
5ba9f198 555
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556Arrays are fixed-length. Their length is declared in the type
557declaration within the meta-data. They contain an array of "inner type"
558elements, which can refer to any type not containing the type of the
559array being declared (no circular dependency). The length is the number
560of elements in an array.
5ba9f198 561
6672e9e1 562TSDL meta-data representation of a named array:
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563
564typedef elem_type name[length];
5ba9f198 565
2152348f 566A nameless array can be declared as a field type within a structure, e.g.:
5ba9f198 567
2152348f 568 uint8_t field_name[10];
80fd2569 569
ec4404a7 570Arrays are always aligned on their element alignment requirement.
5ba9f198 571
fcba70d4 5724.2.4 Sequences
5ba9f198 573
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574Sequences are dynamically-sized arrays. They refer to a a "length"
575unsigned integer field, which must appear in either the same lexical scope,
576prior to the sequence field (in field declaration order), in an upper
577lexical scope (see Section 7.3.1), or in an upper dynamic scope (see
578Section 7.3.2). This length field represents the number of elements in
579the sequence. The sequence per se is an array of "inner type" elements.
5ba9f198 580
1ab22b2a 581TSDL meta-data representation for a sequence type definition:
80fd2569 582
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583struct {
584 unsigned int length_field;
585 typedef elem_type typename[length_field];
586 typename seq_field_name;
587}
588
589A sequence can also be declared as a field type, e.g.:
80fd2569 590
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591struct {
592 unsigned int length_field;
593 long seq_field_name[length_field];
594}
80fd2569 595
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596Multiple sequences can refer to the same length field, and these length
597fields can be in a different upper dynamic scope:
598
599e.g., assuming the stream.event.header defines:
600
601stream {
602 ...
603 id = 1;
604 event.header := struct {
605 uint16_t seq_len;
606 };
607};
608
609event {
610 ...
611 stream_id = 1;
612 fields := struct {
613 long seq_a[stream.event.header.seq_len];
614 char seq_b[stream.event.header.seq_len];
615 };
616};
80fd2569 617
1ab22b2a 618The sequence elements follow the "array" specifications.
5ba9f198 619
fcba70d4 6204.2.5 Strings
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621
622Strings are an array of bytes of variable size and are terminated by a '\0'
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623"NULL" character. Their encoding is described in the TSDL meta-data. In
624absence of encoding attribute information, the default encoding is
625UTF-8.
5ba9f198 626
6672e9e1 627TSDL meta-data representation of a named string type:
80fd2569 628
359894ac 629typealias string {
5ba9f198 630 encoding = UTF8 OR ASCII;
38b8da21 631} := name;
5ba9f198 632
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633A nameless string type can be declared as a field type:
634
635string field_name; /* Use default UTF8 encoding */
5ba9f198 636
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637Strings are always aligned on byte size.
638
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6395. Event Packet Header
640
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641The event packet header consists of two parts: the "event packet header"
642is the same for all streams of a trace. The second part, the "event
643packet context", is described on a per-stream basis. Both are described
644in the TSDL meta-data. The packets are aligned on architecture-page-sized
645addresses.
3bf79539 646
6672e9e1 647Event packet header (all fields are optional, specified by TSDL meta-data):
3bf79539 648
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649- Magic number (CTF magic number: 0xC1FC1FC1) specifies that this is a
650 CTF packet. This magic number is optional, but when present, it should
651 come at the very beginning of the packet.
652- Trace UUID, used to ensure the event packet match the meta-data used.
653 (note: we cannot use a meta-data checksum in every cases instead of a
654 UUID because meta-data can be appended to while tracing is active)
655 This field is optional.
656- Stream ID, used as reference to stream description in meta-data.
657 This field is optional if there is only one stream description in the
658 meta-data, but becomes required if there are more than one stream in
659 the TSDL meta-data description.
3bf79539 660
6672e9e1 661Event packet context (all fields are optional, specified by TSDL meta-data):
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662
663- Event packet content size (in bytes).
664- Event packet size (in bytes, includes padding).
665- Event packet content checksum (optional). Checksum excludes the event packet
666 header.
667- Per-stream event packet sequence count (to deal with UDP packet loss). The
668 number of significant sequence counter bits should also be present, so
b11853af 669 wrap-arounds are dealt with correctly.
6672e9e1 670- Time-stamp at the beginning and time-stamp at the end of the event packet.
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671 Both timestamps are written in the packet header, but sampled respectively
672 while (or before) writing the first event and while (or after) writing the
673 last event in the packet. The inclusive range between these timestamps should
674 include all event timestamps assigned to events contained within the packet.
5ba9f198 675- Events discarded count
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676 - Snapshot of a per-stream free-running counter, counting the number of
677 events discarded that were supposed to be written in the stream prior to
678 the first event in the event packet.
5ba9f198 679 * Note: producer-consumer buffer full condition should fill the current
3bf79539 680 event packet with padding so we know exactly where events have been
5ba9f198 681 discarded.
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682- Lossless compression scheme used for the event packet content. Applied
683 directly to raw data. New types of compression can be added in following
684 versions of the format.
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685 0: no compression scheme
686 1: bzip2
687 2: gzip
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688 3: xz
689- Cypher used for the event packet content. Applied after compression.
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690 0: no encryption
691 1: AES
3bf79539 692- Checksum scheme used for the event packet content. Applied after encryption.
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693 0: no checksum
694 1: md5
695 2: sha1
696 3: crc32
697
6672e9e1 6985.1 Event Packet Header Description
3bf79539 699
fc5425db 700The event packet header layout is indicated by the trace packet.header
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701field. Here is a recommended structure type for the packet header with
702the fields typically expected (although these fields are each optional):
fc5425db 703
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704struct event_packet_header {
705 uint32_t magic;
3fde5da1 706 uint8_t uuid[16];
3bf79539 707 uint32_t stream_id;
80fd2569 708};
5ba9f198 709
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710trace {
711 ...
712 packet.header := struct event_packet_header;
713};
714
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715If the magic number is not present, tools such as "file" will have no
716mean to discover the file type.
717
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718If the uuid is not present, no validation that the meta-data actually
719corresponds to the stream is performed.
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720
721If the stream_id packet header field is missing, the trace can only
722contain a single stream. Its "id" field can be left out, and its events
723don't need to declare a "stream_id" field.
724
725
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7265.2 Event Packet Context Description
727
728Event packet context example. These are declared within the stream declaration
6672e9e1 729in the meta-data. All these fields are optional. If the packet size field is
6a7c61df 730missing, the whole stream only contains a single packet. If the content
f6b81726
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731size field is missing, the packet is filled (no padding). The content
732and packet sizes include all headers.
3bf79539
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733
734An example event packet context type:
735
80fd2569 736struct event_packet_context {
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737 uint64_t timestamp_begin;
738 uint64_t timestamp_end;
739 uint32_t checksum;
740 uint32_t stream_packet_count;
741 uint32_t events_discarded;
742 uint32_t cpu_id;
743 uint32_t/uint16_t content_size;
744 uint32_t/uint16_t packet_size;
745 uint8_t stream_packet_count_bits; /* Significant counter bits */
746 uint8_t compression_scheme;
747 uint8_t encryption_scheme;
3b0f8e4d 748 uint8_t checksum_scheme;
3bf79539 749};
5ba9f198 750
fcba70d4 751
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7526. Event Structure
753
754The overall structure of an event is:
755
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7561 - Stream Packet Context (as specified by the stream meta-data)
757 2 - Event Header (as specified by the stream meta-data)
758 3 - Stream Event Context (as specified by the stream meta-data)
759 4 - Event Context (as specified by the event meta-data)
760 5 - Event Payload (as specified by the event meta-data)
5ba9f198 761
fdf2bb05 762This structure defines an implicit dynamic scoping, where variants
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763located in inner structures (those with a higher number in the listing
764above) can refer to the fields of outer structures (with lower number in
6c7226e9 765the listing above). See Section 7.3 TSDL Scopes for more detail.
5ba9f198 766
fdf2bb05 7676.1 Event Header
fcba70d4 768
6672e9e1 769Event headers can be described within the meta-data. We hereby propose, as an
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770example, two types of events headers. Type 1 accommodates streams with less than
77131 event IDs. Type 2 accommodates streams with 31 or more event IDs.
5ba9f198 772
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773One major factor can vary between streams: the number of event IDs assigned to
774a stream. Luckily, this information tends to stay relatively constant (modulo
5ba9f198 775event registration while trace is being recorded), so we can specify different
3bf79539 776representations for streams containing few event IDs and streams containing
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777many event IDs, so we end up representing the event ID and time-stamp as
778densely as possible in each case.
5ba9f198 779
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780The header is extended in the rare occasions where the information cannot be
781represented in the ranges available in the standard event header. They are also
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782used in the rare occasions where the data required for a field could not be
783collected: the flag corresponding to the missing field within the missing_fields
784array is then set to 1.
5ba9f198 785
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786Types uintX_t represent an X-bit unsigned integer, as declared with
787either:
5ba9f198 788
6672e9e1
MD
789 typealias integer { size = X; align = X; signed = false } := uintX_t;
790
791 or
792
793 typealias integer { size = X; align = 1; signed = false } := uintX_t;
5ba9f198 794
fdf2bb05 7956.1.1 Type 1 - Few event IDs
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796
797 - Aligned on 32-bit (or 8-bit if byte-packed, depending on the architecture
798 preference).
5ba9f198 799 - Native architecture byte ordering.
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800 - For "compact" selection
801 - Fixed size: 32 bits.
802 - For "extended" selection
803 - Size depends on the architecture and variant alignment.
5ba9f198 804
80fd2569 805struct event_header_1 {
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806 /*
807 * id: range: 0 - 30.
808 * id 31 is reserved to indicate an extended header.
809 */
a9b83695 810 enum : uint5_t { compact = 0 ... 30, extended = 31 } id;
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811 variant <id> {
812 struct {
813 uint27_t timestamp;
814 } compact;
815 struct {
816 uint32_t id; /* 32-bit event IDs */
817 uint64_t timestamp; /* 64-bit timestamps */
818 } extended;
819 } v;
cb108fea 820} align(32); /* or align(8) */
5ba9f198 821
5ba9f198 822
fdf2bb05 8236.1.2 Type 2 - Many event IDs
5ba9f198 824
fcba70d4 825 - Aligned on 16-bit (or 8-bit if byte-packed, depending on the architecture
5ba9f198 826 preference).
5ba9f198 827 - Native architecture byte ordering.
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828 - For "compact" selection
829 - Size depends on the architecture and variant alignment.
830 - For "extended" selection
831 - Size depends on the architecture and variant alignment.
5ba9f198 832
80fd2569 833struct event_header_2 {
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834 /*
835 * id: range: 0 - 65534.
836 * id 65535 is reserved to indicate an extended header.
837 */
a9b83695 838 enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;
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839 variant <id> {
840 struct {
841 uint32_t timestamp;
842 } compact;
843 struct {
844 uint32_t id; /* 32-bit event IDs */
845 uint64_t timestamp; /* 64-bit timestamps */
846 } extended;
847 } v;
cb108fea 848} align(16); /* or align(8) */
5ba9f198 849
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850
8516.2 Event Context
852
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853The event context contains information relative to the current event.
854The choice and meaning of this information is specified by the TSDL
855stream and event meta-data descriptions. The stream context is applied
856to all events within the stream. The stream context structure follows
857the event header. The event context is applied to specific events. Its
858structure follows the stream context structure.
5ba9f198 859
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860An example of stream-level event context is to save the event payload size with
861each event, or to save the current PID with each event. These are declared
6672e9e1 862within the stream declaration within the meta-data:
5ba9f198 863
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864 stream {
865 ...
6672e9e1 866 event.context := struct {
80fd2569
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867 uint pid;
868 uint16_t payload_size;
6672e9e1 869 };
fcba70d4
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870 };
871
872An example of event-specific event context is to declare a bitmap of missing
873fields, only appended after the stream event context if the extended event
874header is selected. NR_FIELDS is the number of fields within the event (a
875numeric value).
5ba9f198 876
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877 event {
878 context = struct {
879 variant <id> {
880 struct { } compact;
881 struct {
882 uint1_t missing_fields[NR_FIELDS]; /* missing event fields bitmap */
883 } extended;
884 } v;
885 };
886 ...
887 }
5ba9f198
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888
8896.3 Event Payload
890
891An event payload contains fields specific to a given event type. The fields
6672e9e1 892belonging to an event type are described in the event-specific meta-data
5ba9f198
MD
893within a structure type.
894
8956.3.1 Padding
896
897No padding at the end of the event payload. This differs from the ISO/C standard
898for structures, but follows the CTF standard for structures. In a trace, even
899though it makes sense to align the beginning of a structure, it really makes no
900sense to add padding at the end of the structure, because structures are usually
901not followed by a structure of the same type.
902
903This trick can be done by adding a zero-length "end" field at the end of the C
904structures, and by using the offset of this field rather than using sizeof()
3bf79539 905when calculating the size of a structure (see Appendix "A. Helper macros").
5ba9f198
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906
9076.3.2 Alignment
908
909The event payload is aligned on the largest alignment required by types
910contained within the payload. (This follows the ISO/C standard for structures)
911
912
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MD
9137. Trace Stream Description Language (TSDL)
914
915The Trace Stream Description Language (TSDL) allows expression of the
916binary trace streams layout in a C99-like Domain Specific Language
917(DSL).
918
919
6672e9e1 9207.1 Meta-data
6c7226e9
MD
921
922The trace stream layout description is located in the trace meta-data.
923The meta-data is itself located in a stream identified by its name:
924"metadata".
5ba9f198 925
6672e9e1
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926The meta-data description can be expressed in two different formats:
927text-only and packet-based. The text-only description facilitates
928generation of meta-data and provides a convenient way to enter the
929meta-data information by hand. The packet-based meta-data provides the
930CTF stream packet facilities (checksumming, compression, encryption,
931network-readiness) for meta-data stream generated and transported by a
932tracer.
933
934The text-only meta-data file is a plain text TSDL description.
935
936The packet-based meta-data is made of "meta-data packets", which each
937start with a meta-data packet header. The packet-based meta-data
938description is detected by reading the magic number "0x75D11D57" at the
939beginning of the file. This magic number is also used to detect the
940endianness of the architecture by trying to read the CTF magic number
941and its counterpart in reversed endianness. The events within the
942meta-data stream have no event header nor event context. Each event only
5ae2352d 943contains a "sequence" payload, which is a sequence of bits using the
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944"trace.packet.header.content_size" field as a placeholder for its length
945(the packet header size should be substracted). The formatting of this
946sequence of bits is a plain-text representation of the TSDL description.
947Each meta-data packet start with a special packet header, specific to
948the meta-data stream, which contains, exactly:
6672e9e1
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949
950struct metadata_packet_header {
2daeaa3a 951 uint32_t magic; /* 0x75D11D57 */
3fde5da1 952 uint8_t uuid[16]; /* Unique Universal Identifier */
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953 uint32_t checksum; /* 0 if unused */
954 uint32_t content_size; /* in bits */
955 uint32_t packet_size; /* in bits */
956 uint8_t compression_scheme; /* 0 if unused */
957 uint8_t encryption_scheme; /* 0 if unused */
958 uint8_t checksum_scheme; /* 0 if unused */
959};
960
961The packet-based meta-data can be converted to a text-only meta-data by
962concatenating all the strings in contains.
4fafe1ad 963
6672e9e1
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964In the textual representation of the meta-data, the text contained
965within "/*" and "*/", as well as within "//" and end of line, are
966treated as comments. Boolean values can be represented as true, TRUE,
967or 1 for true, and false, FALSE, or 0 for false. Within the string-based
968meta-data description, the trace UUID is represented as a string of
969hexadecimal digits and dashes "-". In the event packet header, the trace
970UUID is represented as an array of bytes.
fcba70d4 971
fdf2bb05 972
6c7226e9 9737.2 Declaration vs Definition
fdf2bb05
MD
974
975A declaration associates a layout to a type, without specifying where
976this type is located in the event structure hierarchy (see Section 6).
977This therefore includes typedef, typealias, as well as all type
978specifiers. In certain circumstances (typedef, structure field and
979variant field), a declaration is followed by a declarator, which specify
980the newly defined type name (for typedef), or the field name (for
981declarations located within structure and variants). Array and sequence,
982declared with square brackets ("[" "]"), are part of the declarator,
a9b83695 983similarly to C99. The enumeration base type is specified by
6c7226e9 984": enum_base", which is part of the type specifier. The variant tag
a9b83695 985name, specified between "<" ">", is also part of the type specifier.
fdf2bb05
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986
987A definition associates a type to a location in the event structure
b9606a77
MD
988hierarchy (see Section 6). This association is denoted by ":=", as shown
989in Section 7.3.
fdf2bb05
MD
990
991
6c7226e9 9927.3 TSDL Scopes
fdf2bb05 993
6c7226e9
MD
994TSDL uses two different types of scoping: a lexical scope is used for
995declarations and type definitions, and a dynamic scope is used for
2e7d7fcb
MD
996variants references to tag fields and for sequence references to length
997fields.
fdf2bb05 998
6c7226e9 9997.3.1 Lexical Scope
fdf2bb05 1000
d285084f
MD
1001Each of "trace", "stream", "event", "struct" and "variant" have their own
1002nestable declaration scope, within which types can be declared using "typedef"
fdf2bb05 1003and "typealias". A root declaration scope also contains all declarations
7d9d7e92 1004located outside of any of the aforementioned declarations. An inner
fdf2bb05 1005declaration scope can refer to type declared within its container
7d9d7e92
MD
1006lexical scope prior to the inner declaration scope. Redefinition of a
1007typedef or typealias is not valid, although hiding an upper scope
fdf2bb05
MD
1008typedef or typealias is allowed within a sub-scope.
1009
6c7226e9 10107.3.2 Dynamic Scope
fdf2bb05 1011
7d9d7e92
MD
1012A dynamic scope consists in the lexical scope augmented with the
1013implicit event structure definition hierarchy presented at Section 6.
2e7d7fcb
MD
1014The dynamic scope is used for variant tag and sequence length
1015definitions. It is used at definition time to look up the location of
1016the tag field associated with a variant, and to lookup up the location
1017of the length field associated with a sequence.
1018
1019Therefore, variants (or sequences) in lower levels in the dynamic scope
1020(e.g. event context) can refer to a tag (or length) field located in
1021upper levels (e.g. in the event header) by specifying, in this case, the
1022associated tag with <header.field_name>. This allows, for instance, the
1023event context to define a variant referring to the "id" field of the
1024event header as selector.
fdf2bb05
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1025
1026The target dynamic scope must be specified explicitly when referring to
1027a field outside of the local static scope. The dynamic scope prefixes
1028are thus:
1029
e0d9e2c7 1030 - Trace Packet Header: <trace.packet.header. >,
7d9d7e92
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1031 - Stream Packet Context: <stream.packet.context. >,
1032 - Event Header: <stream.event.header. >,
1033 - Stream Event Context: <stream.event.context. >,
1034 - Event Context: <event.context. >,
1035 - Event Payload: <event.fields. >.
fdf2bb05
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1036
1037Multiple declarations of the same field name within a single scope is
1038not valid. It is however valid to re-use the same field name in
1039different scopes. There is no possible conflict, because the dynamic
1040scope must be specified when a variant refers to a tag field located in
1041a different dynamic scope.
1042
457d8b0a
MD
1043The information available in the dynamic scopes can be thought of as the
1044current tracing context. At trace production, information about the
1045current context is saved into the specified scope field levels. At trace
1046consumption, for each event, the current trace context is therefore
1047readable by accessing the upper dynamic scopes.
1048
fdf2bb05 1049
6c7226e9 10507.4 TSDL Examples
d285084f 1051
6672e9e1 1052The grammar representing the TSDL meta-data is presented in Appendix C.
7df6b93a 1053TSDL Grammar. This section presents a rather lighter reading that
6672e9e1 1054consists in examples of TSDL meta-data, with template values.
969f30c0 1055
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1056The stream "id" can be left out if there is only one stream in the
1057trace. The event "id" field can be left out if there is only one event
1058in a stream.
1059
5ba9f198 1060trace {
fdf2bb05 1061 major = value; /* Trace format version */
5ba9f198 1062 minor = value;
fdf2bb05 1063 uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"; /* Trace UUID */
58997e9e 1064 byte_order = be OR le; /* Endianness (required) */
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1065 packet.header := struct {
1066 uint32_t magic;
3fde5da1 1067 uint8_t uuid[16];
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1068 uint32_t stream_id;
1069 };
3bf79539 1070};
5ba9f198 1071
3bf79539
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1072stream {
1073 id = stream_id;
fdf2bb05 1074 /* Type 1 - Few event IDs; Type 2 - Many event IDs. See section 6.1. */
4fa992a5
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1075 event.header := event_header_1 OR event_header_2;
1076 event.context := struct {
77a98c82 1077 ...
3bf79539 1078 };
4fa992a5 1079 packet.context := struct {
77a98c82 1080 ...
3bf79539
MD
1081 };
1082};
5ba9f198
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1083
1084event {
3d13ef1a 1085 name = event_name;
3bf79539 1086 id = value; /* Numeric identifier within the stream */
67f02e24 1087 stream_id = stream_id;
4fa992a5 1088 context := struct {
fcba70d4
MD
1089 ...
1090 };
4fa992a5 1091 fields := struct {
80fd2569
MD
1092 ...
1093 };
3bf79539 1094};
5ba9f198
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1095
1096/* More detail on types in section 4. Types */
1097
3d13ef1a
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1098/*
1099 * Named types:
1100 *
4fa992a5 1101 * Type declarations behave similarly to the C standard.
3d13ef1a
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1102 */
1103
80af8ac6 1104typedef aliased_type_specifiers new_type_declarators;
2152348f 1105
3d13ef1a 1106/* e.g.: typedef struct example new_type_name[10]; */
80fd2569 1107
4fa992a5
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1108/*
1109 * typealias
1110 *
1111 * The "typealias" declaration can be used to give a name (including
80af8ac6
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1112 * pointer declarator specifier) to a type. It should also be used to
1113 * map basic C types (float, int, unsigned long, ...) to a CTF type.
1114 * Typealias is a superset of "typedef": it also allows assignment of a
38b8da21 1115 * simple variable identifier to a type.
4fa992a5
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1116 */
1117
1118typealias type_class {
80fd2569 1119 ...
38b8da21 1120} := type_specifiers type_declarator;
2152348f 1121
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1122/*
1123 * e.g.:
4fa992a5 1124 * typealias integer {
3d13ef1a
MD
1125 * size = 32;
1126 * align = 32;
1127 * signed = false;
38b8da21 1128 * } := struct page *;
359894ac
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1129 *
1130 * typealias integer {
1131 * size = 32;
1132 * align = 32;
1133 * signed = true;
38b8da21 1134 * } := int;
3d13ef1a 1135 */
80fd2569
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1136
1137struct name {
3bf79539
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1138 ...
1139};
5ba9f198 1140
fcba70d4
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1141variant name {
1142 ...
1143};
1144
a9b83695 1145enum name : integer_type {
3bf79539
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1146 ...
1147};
1148
2152348f 1149
4fa992a5
MD
1150/*
1151 * Unnamed types, contained within compound type fields, typedef or typealias.
1152 */
2152348f 1153
80fd2569
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1154struct {
1155 ...
2152348f 1156}
5ba9f198 1157
ec4404a7
MD
1158struct {
1159 ...
1160} align(value)
1161
fcba70d4
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1162variant {
1163 ...
1164}
1165
a9b83695 1166enum : integer_type {
80fd2569 1167 ...
2152348f
MD
1168}
1169
1170typedef type new_type[length];
3bf79539 1171
2152348f
MD
1172struct {
1173 type field_name[length];
1174}
1175
1176typedef type new_type[length_type];
1177
1178struct {
1179 type field_name[length_type];
1180}
1181
1182integer {
80fd2569 1183 ...
2152348f 1184}
3bf79539 1185
2152348f 1186floating_point {
80fd2569 1187 ...
2152348f
MD
1188}
1189
1190struct {
1191 integer_type field_name:size; /* GNU/C bitfield */
1192}
1193
1194struct {
1195 string field_name;
1196}
3bf79539 1197
fcba70d4 1198
3bf79539 1199A. Helper macros
5ba9f198
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1200
1201The two following macros keep track of the size of a GNU/C structure without
1202padding at the end by placing HEADER_END as the last field. A one byte end field
1203is used for C90 compatibility (C99 flexible arrays could be used here). Note
1204that this does not affect the effective structure size, which should always be
1205calculated with the header_sizeof() helper.
1206
1207#define HEADER_END char end_field
1208#define header_sizeof(type) offsetof(typeof(type), end_field)
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1209
1210
1211B. Stream Header Rationale
1212
1213An event stream is divided in contiguous event packets of variable size. These
1214subdivisions allow the trace analyzer to perform a fast binary search by time
1215within the stream (typically requiring to index only the event packet headers)
1216without reading the whole stream. These subdivisions have a variable size to
1217eliminate the need to transfer the event packet padding when partially filled
1218event packets must be sent when streaming a trace for live viewing/analysis.
1219An event packet can contain a certain amount of padding at the end. Dividing
1220streams into event packets is also useful for network streaming over UDP and
1221flight recorder mode tracing (a whole event packet can be swapped out of the
1222buffer atomically for reading).
1223
1224The stream header is repeated at the beginning of each event packet to allow
1225flexibility in terms of:
1226
1227 - streaming support,
1228 - allowing arbitrary buffers to be discarded without making the trace
1229 unreadable,
1230 - allow UDP packet loss handling by either dealing with missing event packet
1231 or asking for re-transmission.
1232 - transparently support flight recorder mode,
1233 - transparently support crash dump.
1234
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1235
1236C. TSDL Grammar
fcba70d4 1237
4fa992a5 1238/*
6c7226e9 1239 * Common Trace Format (CTF) Trace Stream Description Language (TSDL) Grammar.
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1240 *
1241 * Inspired from the C99 grammar:
1242 * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf (Annex A)
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1243 * and c++1x grammar (draft)
1244 * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3291.pdf (Annex A)
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1245 *
1246 * Specialized for CTF needs by including only constant and declarations from
1247 * C99 (excluding function declarations), and by adding support for variants,
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1248 * sequences and CTF-specific specifiers. Enumeration container types
1249 * semantic is inspired from c++1x enum-base.
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1250 */
1251
12521) Lexical grammar
1253
12541.1) Lexical elements
1255
1256token:
1257 keyword
1258 identifier
1259 constant
1260 string-literal
1261 punctuator
1262
12631.2) Keywords
1264
1265keyword: is one of
1266
ec4404a7 1267align
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1268const
1269char
1270double
1271enum
1272event
1273floating_point
1274float
1275integer
1276int
1277long
1278short
1279signed
1280stream
1281string
1282struct
1283trace
3e1e1a78 1284typealias
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1285typedef
1286unsigned
1287variant
1288void
1289_Bool
1290_Complex
1291_Imaginary
1292
1293
12941.3) Identifiers
1295
1296identifier:
1297 identifier-nondigit
1298 identifier identifier-nondigit
1299 identifier digit
1300
1301identifier-nondigit:
1302 nondigit
1303 universal-character-name
1304 any other implementation-defined characters
1305
1306nondigit:
1307 _
1308 [a-zA-Z] /* regular expression */
1309
1310digit:
1311 [0-9] /* regular expression */
1312
13131.4) Universal character names
1314
1315universal-character-name:
1316 \u hex-quad
1317 \U hex-quad hex-quad
1318
1319hex-quad:
1320 hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit
1321
13221.5) Constants
1323
1324constant:
1325 integer-constant
1326 enumeration-constant
1327 character-constant
1328
1329integer-constant:
1330 decimal-constant integer-suffix-opt
1331 octal-constant integer-suffix-opt
1332 hexadecimal-constant integer-suffix-opt
1333
1334decimal-constant:
1335 nonzero-digit
1336 decimal-constant digit
1337
1338octal-constant:
1339 0
1340 octal-constant octal-digit
1341
1342hexadecimal-constant:
1343 hexadecimal-prefix hexadecimal-digit
1344 hexadecimal-constant hexadecimal-digit
1345
1346hexadecimal-prefix:
1347 0x
1348 0X
1349
1350nonzero-digit:
1351 [1-9]
1352
1353integer-suffix:
1354 unsigned-suffix long-suffix-opt
1355 unsigned-suffix long-long-suffix
1356 long-suffix unsigned-suffix-opt
1357 long-long-suffix unsigned-suffix-opt
1358
1359unsigned-suffix:
1360 u
1361 U
1362
1363long-suffix:
1364 l
1365 L
1366
1367long-long-suffix:
1368 ll
1369 LL
1370
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1371enumeration-constant:
1372 identifier
1373 string-literal
1374
1375character-constant:
1376 ' c-char-sequence '
1377 L' c-char-sequence '
1378
1379c-char-sequence:
1380 c-char
1381 c-char-sequence c-char
1382
1383c-char:
1384 any member of source charset except single-quote ('), backslash
1385 (\), or new-line character.
1386 escape-sequence
1387
1388escape-sequence:
1389 simple-escape-sequence
1390 octal-escape-sequence
1391 hexadecimal-escape-sequence
1392 universal-character-name
1393
1394simple-escape-sequence: one of
1395 \' \" \? \\ \a \b \f \n \r \t \v
1396
1397octal-escape-sequence:
1398 \ octal-digit
1399 \ octal-digit octal-digit
1400 \ octal-digit octal-digit octal-digit
1401
1402hexadecimal-escape-sequence:
1403 \x hexadecimal-digit
1404 hexadecimal-escape-sequence hexadecimal-digit
1405
14061.6) String literals
1407
1408string-literal:
1409 " s-char-sequence-opt "
1410 L" s-char-sequence-opt "
1411
1412s-char-sequence:
1413 s-char
1414 s-char-sequence s-char
1415
1416s-char:
1417 any member of source charset except double-quote ("), backslash
1418 (\), or new-line character.
1419 escape-sequence
1420
14211.7) Punctuators
1422
1423punctuator: one of
1424 [ ] ( ) { } . -> * + - < > : ; ... = ,
1425
1426
14272) Phrase structure grammar
1428
1429primary-expression:
1430 identifier
1431 constant
1432 string-literal
1433 ( unary-expression )
1434
1435postfix-expression:
1436 primary-expression
1437 postfix-expression [ unary-expression ]
1438 postfix-expression . identifier
1439 postfix-expressoin -> identifier
1440
1441unary-expression:
1442 postfix-expression
1443 unary-operator postfix-expression
1444
1445unary-operator: one of
1446 + -
1447
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1448assignment-operator:
1449 =
1450
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1451type-assignment-operator:
1452 :=
1453
4fa992a5 1454constant-expression-range:
73d61ac3 1455 unary-expression ... unary-expression
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1456
14572.2) Declarations:
1458
1459declaration:
689e04b4 1460 declaration-specifiers declarator-list-opt ;
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1461 ctf-specifier ;
1462
1463declaration-specifiers:
689e04b4 1464 storage-class-specifier declaration-specifiers-opt
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1465 type-specifier declaration-specifiers-opt
1466 type-qualifier declaration-specifiers-opt
1467
1468declarator-list:
1469 declarator
1470 declarator-list , declarator
1471
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1472abstract-declarator-list:
1473 abstract-declarator
1474 abstract-declarator-list , abstract-declarator
1475
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1476storage-class-specifier:
1477 typedef
1478
1479type-specifier:
1480 void
1481 char
1482 short
1483 int
1484 long
1485 float
1486 double
1487 signed
1488 unsigned
1489 _Bool
1490 _Complex
cfdd51ec 1491 _Imaginary
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1492 struct-specifier
1493 variant-specifier
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1494 enum-specifier
1495 typedef-name
1496 ctf-type-specifier
1497
ec4404a7 1498align-attribute:
73d61ac3 1499 align ( unary-expression )
ec4404a7 1500
4fa992a5 1501struct-specifier:
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1502 struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
1503 struct identifier align-attribute-opt
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1504
1505struct-or-variant-declaration-list:
1506 struct-or-variant-declaration
1507 struct-or-variant-declaration-list struct-or-variant-declaration
1508
1509struct-or-variant-declaration:
1510 specifier-qualifier-list struct-or-variant-declarator-list ;
eacb16d1 1511 declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt declarator-list ;
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1512 typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list ;
1513 typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list ;
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1514
1515specifier-qualifier-list:
1516 type-specifier specifier-qualifier-list-opt
1517 type-qualifier specifier-qualifier-list-opt
1518
1519struct-or-variant-declarator-list:
1520 struct-or-variant-declarator
1521 struct-or-variant-declarator-list , struct-or-variant-declarator
1522
1523struct-or-variant-declarator:
1524 declarator
73d61ac3 1525 declarator-opt : unary-expression
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1526
1527variant-specifier:
1528 variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
1529 variant identifier variant-tag
1530
1531variant-tag:
1532 < identifier >
1533
1534enum-specifier:
1535 enum identifier-opt { enumerator-list }
1536 enum identifier-opt { enumerator-list , }
1537 enum identifier
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1538 enum identifier-opt : declaration-specifiers { enumerator-list }
1539 enum identifier-opt : declaration-specifiers { enumerator-list , }
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1540
1541enumerator-list:
1542 enumerator
1543 enumerator-list , enumerator
1544
1545enumerator:
1546 enumeration-constant
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1547 enumeration-constant assignment-operator unary-expression
1548 enumeration-constant assignment-operator constant-expression-range
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1549
1550type-qualifier:
1551 const
1552
1553declarator:
1554 pointer-opt direct-declarator
1555
1556direct-declarator:
1557 identifier
1558 ( declarator )
1ab22b2a 1559 direct-declarator [ unary-expression ]
4fa992a5 1560
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1561abstract-declarator:
1562 pointer-opt direct-abstract-declarator
1563
1564direct-abstract-declarator:
1565 identifier-opt
1566 ( abstract-declarator )
1ab22b2a 1567 direct-abstract-declarator [ unary-expression ]
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1568 direct-abstract-declarator [ ]
1569
4fa992a5 1570pointer:
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1571 * type-qualifier-list-opt
1572 * type-qualifier-list-opt pointer
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1573
1574type-qualifier-list:
1575 type-qualifier
1576 type-qualifier-list type-qualifier
1577
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1578typedef-name:
1579 identifier
1580
15812.3) CTF-specific declarations
1582
1583ctf-specifier:
1584 event { ctf-assignment-expression-list-opt }
1585 stream { ctf-assignment-expression-list-opt }
1586 trace { ctf-assignment-expression-list-opt }
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1587 typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list
1588 typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list
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1589
1590ctf-type-specifier:
1591 floating_point { ctf-assignment-expression-list-opt }
1592 integer { ctf-assignment-expression-list-opt }
1593 string { ctf-assignment-expression-list-opt }
7609d3c7 1594 string
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1595
1596ctf-assignment-expression-list:
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1597 ctf-assignment-expression ;
1598 ctf-assignment-expression-list ctf-assignment-expression ;
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1599
1600ctf-assignment-expression:
1601 unary-expression assignment-operator unary-expression
1602 unary-expression type-assignment-operator type-specifier
eacb16d1 1603 declaration-specifiers-opt storage-class-specifier declaration-specifiers-opt declarator-list
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1604 typealias declaration-specifiers abstract-declarator-list type-assignment-operator declaration-specifiers abstract-declarator-list
1605 typealias declaration-specifiers abstract-declarator-list type-assignment-operator declarator-list
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