GCC Middle and Back End API Reference
gcov-io.h
Go to the documentation of this file.
1/* File format for coverage information
2 Copyright (C) 1996-2024 Free Software Foundation, Inc.
3 Contributed by Bob Manson <manson@cygnus.com>.
4 Completely remangled by Nathan Sidwell <nathan@codesourcery.com>.
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 3, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
17
18Under Section 7 of GPL version 3, you are granted additional
19permissions described in the GCC Runtime Library Exception, version
203.1, as published by the Free Software Foundation.
21
22You should have received a copy of the GNU General Public License and
23a copy of the GCC Runtime Library Exception along with this program;
24see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25<http://www.gnu.org/licenses/>. */
26
27
28/* CAVEAT: Coverage information files should not be parsed directly,
29 instead use `gcov --json-format`, which provides
30 machine-readable coverage information.
31
32 Note that the following file format documentation might be outdated.
33
34 Coverage information is held in two files. A notes file, which is
35 generated by the compiler, and a data file, which is generated by
36 the program under test. Both files use a similar structure. We do
37 not attempt to make these files backwards compatible with previous
38 versions, as you only need coverage information when developing a
39 program. We do hold version information, so that mismatches can be
40 detected, and we use a format that allows tools to skip information
41 they do not understand or are not interested in.
42
43 Numbers are recorded in the 32 bit unsigned binary form of the
44 endianness of the machine generating the file. 64 bit numbers are
45 stored as two 32 bit numbers, the low part first.
46 The number of bytes is stored, followed by the
47 string. Zero length and NULL strings are simply stored as a length
48 of zero (they have no trailing NUL).
49
50 int32: byte3 byte2 byte1 byte0 | byte0 byte1 byte2 byte3
51 int64: int32:low int32:high
52 string: int32:0 | int32:length char* char:0
53 item: int32 | int64 | string
54
55 The basic format of the notes file is
56
57 file : int32:magic int32:version int32:stamp int32:support_unexecuted_blocks record*
58
59 The basic format of the data file is
60
61 file : int32:magic int32:version int32:stamp record*
62
63 A filename header may be used to provide a filename for the data in
64 a stream of data to support gcov in freestanding environments. This
65 header is used by the merge-stream subcommand of the gcov-tool. The
66 format of the filename header is
67
68 filename-header : int32:magic int32:version string
69
70 The magic ident is different for the notes and the data files as
71 well as the filename header. The magic ident is used to determine
72 the endianness of the file, when reading. The version is the same
73 for both files and is derived from gcc's version number. The stamp
74 value is used to synchronize note and data files and to synchronize
75 merging within a data file. It need not be an absolute time stamp,
76 merely a ticker that increments fast enough and cycles slow enough
77 to distinguish different compile/run/compile cycles.
78
79 Although the ident and version are formally 32 bit numbers, they
80 are derived from 4 character ASCII strings. The version number
81 consists of a two character major version number
82 (first digit starts from 'A' letter to not to clash with the older
83 numbering scheme), the single character minor version number,
84 and a single character indicating the status of the release.
85 That will be 'e' experimental, 'p' prerelease and 'r' for release.
86 Because, by good fortune, these are in alphabetical order, string
87 collating can be used to compare version strings. Be aware that
88 the 'e' designation will (naturally) be unstable and might be
89 incompatible with itself. For gcc 17.0 experimental, it would be
90 'B70e' (0x42373065). As we currently do not release more than 5 minor
91 releases, the single character should be always fine. Major number
92 is currently changed roughly every year, which gives us space
93 for next 250 years (maximum allowed number would be 259.9).
94
95 A record has a tag, length and variable amount of data.
96
97 record: header data
98 header: int32:tag int32:length
99 data: item*
100
101 Records are not nested, but there is a record hierarchy. Tag
102 numbers reflect this hierarchy. Tags are unique across note and
103 data files. Some record types have a varying amount of data. The
104 LENGTH is the number of bytes that follow and is usually used to
105 determine how much data. The tag value is split into 4 8-bit
106 fields, one for each of four possible levels. The most significant
107 is allocated first. Unused levels are zero. Active levels are
108 odd-valued, so that the LSB of the level is one. A sub-level
109 incorporates the values of its superlevels. This formatting allows
110 you to determine the tag hierarchy, without understanding the tags
111 themselves, and is similar to the standard section numbering used
112 in technical documents. Level values [1..3f] are used for common
113 tags, values [41..9f] for the notes file and [a1..ff] for the data
114 file.
115
116 The notes file contains the following records
117 note: unit function-graph*
118 unit: header int32:checksum string:source
119 function-graph: announce_function basic_blocks {arcs | lines}*
120 announce_function: header int32:ident
121 int32:lineno_checksum int32:cfg_checksum
122 string:name string:source int32:start_lineno int32:start_column int32:end_lineno
123 basic_block: header int32:flags*
124 arcs: header int32:block_no arc*
125 arc: int32:dest_block int32:flags
126 lines: header int32:block_no line*
127 int32:0 string:NULL
128 line: int32:line_no | int32:0 string:filename
129
130 The BASIC_BLOCK record holds per-bb flags. The number of blocks
131 can be inferred from its data length. There is one ARCS record per
132 basic block. The number of arcs from a bb is implicit from the
133 data length. It enumerates the destination bb and per-arc flags.
134 There is one LINES record per basic block, it enumerates the source
135 lines which belong to that basic block. Source file names are
136 introduced by a line number of 0, following lines are from the new
137 source file. The initial source file for the function is NULL, but
138 the current source file should be remembered from one LINES record
139 to the next. The end of a block is indicated by an empty filename
140 - this does not reset the current source file. Note there is no
141 ordering of the ARCS and LINES records: they may be in any order,
142 interleaved in any manner. The current filename follows the order
143 the LINES records are stored in the file, *not* the ordering of the
144 blocks they are for.
145
146 The data file contains the following records.
147 data: {unit summary:object function-data*}*
148 unit: header int32:checksum
149 function-data: announce_function present counts
150 announce_function: header int32:ident
151 int32:lineno_checksum int32:cfg_checksum
152 present: header int32:present
153 counts: header int64:count*
154 summary: int32:checksum int32:runs int32:sum_max
155
156 The ANNOUNCE_FUNCTION record is the same as that in the note file,
157 but without the source location. The COUNTS gives the
158 counter values for instrumented features. The about the whole
159 program. The checksum is used for whole program summaries, and
160 disambiguates different programs which include the same
161 instrumented object file. There may be several program summaries,
162 each with a unique checksum. The object summary's checksum is
163 zero. Note that the data file might contain information from
164 several runs concatenated, or the data might be merged.
165
166 This file is included by both the compiler, gcov tools and the
167 runtime support library libgcov. IN_LIBGCOV and IN_GCOV are used to
168 distinguish which case is which. If IN_LIBGCOV is nonzero,
169 libgcov is being built. If IN_GCOV is nonzero, the gcov tools are
170 being built. Otherwise the compiler is being built. IN_GCOV may be
171 positive or negative. If positive, we are compiling a tool that
172 requires additional functions (see the code for knowledge of what
173 those functions are). */
174
175#ifndef GCC_GCOV_IO_H
176#define GCC_GCOV_IO_H
177
178/* GCOV key-value pair linked list type. */
179
180struct gcov_kvp;
181
188
189#ifndef IN_LIBGCOV
190/* About the host */
191
192typedef unsigned gcov_unsigned_t;
193typedef unsigned gcov_position_t;
194/* gcov_type is typedef'd elsewhere for the compiler */
195#if IN_GCOV
196#define GCOV_LINKAGE static
197typedef int64_t gcov_type;
198typedef uint64_t gcov_type_unsigned;
199#if IN_GCOV > 0
200#include <sys/types.h>
201#endif
202#endif
203
204#if defined (HOST_HAS_F_SETLKW)
205#define GCOV_LOCKED 1
206#else
207#define GCOV_LOCKED 0
208#endif
209
210#if defined (HOST_HAS_LK_LOCK)
211#define GCOV_LOCKED_WITH_LOCKING 1
212#else
213#define GCOV_LOCKED_WITH_LOCKING 0
214#endif
215
216#define ATTRIBUTE_HIDDEN
217
218#endif /* !IN_LIBGCOV */
219
220#ifndef GCOV_LINKAGE
221#define GCOV_LINKAGE extern
222#endif
223
224#if IN_LIBGCOV
225#define gcov_nonruntime_assert(EXPR) ((void)(0 && (EXPR)))
226#else
227#define gcov_nonruntime_assert(EXPR) gcc_assert (EXPR)
228#define gcov_error(...) fatal_error (input_location, __VA_ARGS__)
229#endif
230
231/* File suffixes. */
232#define GCOV_DATA_SUFFIX ".gcda"
233#define GCOV_NOTE_SUFFIX ".gcno"
234
235/* File magic. Must not be palindromes. */
236#define GCOV_DATA_MAGIC ((gcov_unsigned_t)0x67636461) /* "gcda" */
237#define GCOV_NOTE_MAGIC ((gcov_unsigned_t)0x67636e6f) /* "gcno" */
238#define GCOV_FILENAME_MAGIC ((gcov_unsigned_t)0x6763666e) /* "gcfn" */
239
240#include "version.h"
241
242/* Convert a magic or version number to a 4 character string. */
243#define GCOV_UNSIGNED2STRING(ARRAY,VALUE) \
244 ((ARRAY)[0] = (char)((VALUE) >> 24), \
245 (ARRAY)[1] = (char)((VALUE) >> 16), \
246 (ARRAY)[2] = (char)((VALUE) >> 8), \
247 (ARRAY)[3] = (char)((VALUE) >> 0))
248
249/* The record tags. Values [1..3f] are for tags which may be in either
250 file. Values [41..9f] for those in the note file and [a1..ff] for
251 the data file. The tag value zero is used as an explicit end of
252 file marker -- it is not required to be present.
253 All length values are in bytes. */
254
255#define GCOV_WORD_SIZE 4
256
257#define GCOV_TAG_FUNCTION ((gcov_unsigned_t)0x01000000)
258#define GCOV_TAG_FUNCTION_LENGTH (3 * GCOV_WORD_SIZE)
259#define GCOV_TAG_BLOCKS ((gcov_unsigned_t)0x01410000)
260#define GCOV_TAG_BLOCKS_LENGTH(NUM) (NUM)
261#define GCOV_TAG_ARCS ((gcov_unsigned_t)0x01430000)
262#define GCOV_TAG_ARCS_LENGTH(NUM) (1 + (NUM) * 2 * GCOV_WORD_SIZE)
263#define GCOV_TAG_ARCS_NUM(LENGTH) (((LENGTH / GCOV_WORD_SIZE) - 1) / 2)
264#define GCOV_TAG_CONDS ((gcov_unsigned_t)0x01470000)
265#define GCOV_TAG_CONDS_LENGTH(NUM) ((NUM) * 2 * GCOV_WORD_SIZE)
266#define GCOV_TAG_CONDS_NUM(LENGTH) (((LENGTH) / GCOV_WORD_SIZE) / 2)
267#define GCOV_TAG_LINES ((gcov_unsigned_t)0x01450000)
268#define GCOV_TAG_COUNTER_BASE ((gcov_unsigned_t)0x01a10000)
269#define GCOV_TAG_COUNTER_LENGTH(NUM) ((NUM) * 2 * GCOV_WORD_SIZE)
270#define GCOV_TAG_COUNTER_NUM(LENGTH) ((LENGTH / GCOV_WORD_SIZE) / 2)
271#define GCOV_TAG_OBJECT_SUMMARY ((gcov_unsigned_t)0xa1000000)
272#define GCOV_TAG_OBJECT_SUMMARY_LENGTH (2 * GCOV_WORD_SIZE)
273#define GCOV_TAG_PROGRAM_SUMMARY ((gcov_unsigned_t)0xa3000000) /* Obsolete */
274#define GCOV_TAG_AFDO_FILE_NAMES ((gcov_unsigned_t)0xaa000000)
275#define GCOV_TAG_AFDO_FUNCTION ((gcov_unsigned_t)0xac000000)
276#define GCOV_TAG_AFDO_WORKING_SET ((gcov_unsigned_t)0xaf000000)
277
278
279/* Counters that are collected. */
280
281#define DEF_GCOV_COUNTER(COUNTER, NAME, MERGE_FN) COUNTER,
282enum {
283#include "gcov-counter.def"
286#undef DEF_GCOV_COUNTER
287
288/* The first of counters used for value profiling. They must form a
289 consecutive interval and their order must match the order of
290 HIST_TYPEs in value-prof.h. */
291#define GCOV_FIRST_VALUE_COUNTER GCOV_COUNTER_V_INTERVAL
292
293/* The last of counters used for value profiling. */
294#define GCOV_LAST_VALUE_COUNTER (GCOV_COUNTERS - 1)
295
296/* Number of counters used for value profiling. */
297#define GCOV_N_VALUE_COUNTERS \
298 (GCOV_LAST_VALUE_COUNTER - GCOV_FIRST_VALUE_COUNTER + 1)
299
300/* Number of top N counters when being in memory. */
301#define GCOV_TOPN_MEM_COUNTERS 3
302
303/* Number of top N counters in disk representation. */
304#define GCOV_TOPN_DISK_COUNTERS 2
305
306/* Maximum number of tracked TOP N value profiles. */
307#define GCOV_TOPN_MAXIMUM_TRACKED_VALUES 32
308
309/* Convert a counter index to a tag. */
310#define GCOV_TAG_FOR_COUNTER(COUNT) \
311 (GCOV_TAG_COUNTER_BASE + ((gcov_unsigned_t)(COUNT) << 17))
312/* Convert a tag to a counter. */
313#define GCOV_COUNTER_FOR_TAG(TAG) \
314 ((unsigned)(((TAG) - GCOV_TAG_COUNTER_BASE) >> 17))
315/* Check whether a tag is a counter tag. */
316#define GCOV_TAG_IS_COUNTER(TAG) \
317 (!((TAG) & 0xFFFF) && GCOV_COUNTER_FOR_TAG (TAG) < GCOV_COUNTERS)
318
319/* The tag level mask has 1's in the position of the inner levels, &
320 the lsb of the current level, and zero on the current and outer
321 levels. */
322#define GCOV_TAG_MASK(TAG) (((TAG) - 1) ^ (TAG))
323
324/* Return nonzero if SUB is an immediate subtag of TAG. */
325#define GCOV_TAG_IS_SUBTAG(TAG,SUB) \
326 (GCOV_TAG_MASK (TAG) >> 8 == GCOV_TAG_MASK (SUB) \
327 && !(((SUB) ^ (TAG)) & ~GCOV_TAG_MASK (TAG)))
328
329/* Return nonzero if SUB is at a sublevel to TAG. */
330#define GCOV_TAG_IS_SUBLEVEL(TAG,SUB) \
331 (GCOV_TAG_MASK (TAG) > GCOV_TAG_MASK (SUB))
332
333/* Basic block flags. */
334#define GCOV_BLOCK_UNEXPECTED (1 << 1)
335
336/* Arc flags. */
337#define GCOV_ARC_ON_TREE (1 << 0)
338#define GCOV_ARC_FAKE (1 << 1)
339#define GCOV_ARC_FALLTHROUGH (1 << 2)
340#define GCOV_ARC_TRUE (1 << 3)
341#define GCOV_ARC_FALSE (1 << 4)
342
343/* Object & program summary record. */
344
346{
347 gcov_unsigned_t runs; /* Number of program runs. */
348 gcov_type sum_max; /* Sum of individual run max values. */
349};
350
351#if !defined(inhibit_libc)
352
353/* Functions for reading and writing gcov files. In libgcov you can
354 open the file for reading then writing. Elsewhere you can open the
355 file either for reading or for writing. When reading a file you may
356 use the gcov_read_* functions, gcov_sync, gcov_position, and
357 gcov_error. When writing a file you may use the gcov_write*
358 functions and gcov_error. When a file is to be rewritten
359 you use the functions for reading, then gcov_rewrite then the
360 functions for writing. Your file may become corrupted if you break
361 these invariants. */
362
363#if !IN_LIBGCOV || defined (IN_GCOV_TOOL)
365#endif
366
367/* Available everywhere. */
368GCOV_LINKAGE int gcov_open (const char *, int) ATTRIBUTE_HIDDEN;
373GCOV_LINKAGE const char *gcov_read_string (void);
375 gcov_unsigned_t /*length */);
376char *mangle_path (char const *base);
377
378#if !IN_GCOV
379/* Available outside gcov */
380GCOV_LINKAGE void gcov_write (const void *, unsigned) ATTRIBUTE_HIDDEN;
382#endif
383
384#if !IN_GCOV && !IN_LIBGCOV
385/* Available only in compiler */
386GCOV_LINKAGE void gcov_write_string (const char *);
387GCOV_LINKAGE void gcov_write_filename (const char *);
390#endif
391
392#if IN_GCOV > 0
393/* Available in gcov */
394GCOV_LINKAGE time_t gcov_time (void);
395#endif
396
397#endif /* !inhibit_libc */
398
399#endif /* GCC_GCOV_IO_H */
uint64_t gcov_type_unsigned
Definition coretypes.h:47
int64_t gcov_type
Definition coretypes.h:46
unsigned gcov_unsigned_t
Definition gcov-io.h:192
char * mangle_path(char const *base)
Definition gcov-io.cc:463
GCOV_LINKAGE void gcov_write_filename(const char *)
Definition gcov-io.cc:309
GCOV_LINKAGE gcov_position_t gcov_write_tag(gcov_unsigned_t)
Definition gcov-io.cc:347
#define GCOV_LINKAGE
Definition gcov-io.h:221
GCOV_LINKAGE void gcov_write_unsigned(gcov_unsigned_t) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:275
GCOV_LINKAGE void gcov_read_summary(struct gcov_summary *) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:529
GCOV_LINKAGE gcov_type gcov_read_counter(void) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:442
@ GCOV_COUNTERS
Definition gcov-io.h:284
GCOV_LINKAGE int gcov_close(void) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:223
#define ATTRIBUTE_HIDDEN
Definition gcov-io.h:216
GCOV_LINKAGE void gcov_write_string(const char *)
Definition gcov-io.cc:287
GCOV_LINKAGE gcov_unsigned_t gcov_read_unsigned(void) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:425
unsigned gcov_position_t
Definition gcov-io.h:193
GCOV_LINKAGE void gcov_sync(gcov_position_t, gcov_unsigned_t)
Definition gcov-io.cc:542
GCOV_LINKAGE int gcov_open(const char *, int) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:114
GCOV_LINKAGE void gcov_write(const void *, unsigned) ATTRIBUTE_HIDDEN
Definition gcov-io.cc:265
GCOV_LINKAGE void gcov_write_length(gcov_position_t)
Definition gcov-io.cc:362
GCOV_LINKAGE int gcov_magic(gcov_unsigned_t, gcov_unsigned_t)
Definition gcov-io.cc:247
GCOV_LINKAGE const char * gcov_read_string(void)
Definition gcov-io.cc:516
Definition gcov-io.h:183
struct gcov_kvp * next
Definition gcov-io.h:186
gcov_type value
Definition gcov-io.h:184
gcov_type count
Definition gcov-io.h:185
Definition gcov-io.h:346
gcov_type sum_max
Definition gcov-io.h:348
gcov_unsigned_t runs
Definition gcov-io.h:347