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gcov: support GCC 12.1 and newer compilers
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Starting with GCC 12.1, the created .gcda format can't be read by gcov
tool.  There are 2 significant changes to the .gcda file format that
need to be supported:

a) [gcov: Use system IO buffering]
   (23eb66d1d46a34cb28c4acbdf8a1deb80a7c5a05) changed that all sizes in
   the format are in bytes and not in words (4B)

b) [gcov: make profile merging smarter]
   (72e0c742bd01f8e7e6dcca64042b9ad7e75979de) add a new checksum to the
   file header.

Tested with GCC 7.5, 10.4, 12.2 and the current master.

Link: https://lkml.kernel.org/r/624bda92-f307-30e9-9aaa-8cc678b2dfb2@suse.cz
Signed-off-by: Martin Liska <mliska@suse.cz>
Tested-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Martin Liska authored and Andrew Morton committed Oct 21, 2022
1 parent 4249a05 commit 977ef30
Showing 1 changed file with 16 additions and 2 deletions.
18 changes: 16 additions & 2 deletions kernel/gcov/gcc_4_7.c
Original file line number Diff line number Diff line change
@@ -30,6 +30,13 @@

#define GCOV_TAG_FUNCTION_LENGTH 3

/* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
#if (__GNUC__ >= 12)
#define GCOV_UNIT_SIZE 4
#else
#define GCOV_UNIT_SIZE 1
#endif

static struct gcov_info *gcov_info_head;

/**
@@ -383,12 +390,18 @@ size_t convert_to_gcda(char *buffer, struct gcov_info *info)
pos += store_gcov_u32(buffer, pos, info->version);
pos += store_gcov_u32(buffer, pos, info->stamp);

#if (__GNUC__ >= 12)
/* Use zero as checksum of the compilation unit. */
pos += store_gcov_u32(buffer, pos, 0);
#endif

for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
fi_ptr = info->functions[fi_idx];

/* Function record. */
pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH);
pos += store_gcov_u32(buffer, pos,
GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
@@ -402,7 +415,8 @@ size_t convert_to_gcda(char *buffer, struct gcov_info *info)
/* Counter record. */
pos += store_gcov_u32(buffer, pos,
GCOV_TAG_FOR_COUNTER(ct_idx));
pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2);
pos += store_gcov_u32(buffer, pos,
ci_ptr->num * 2 * GCOV_UNIT_SIZE);

for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
pos += store_gcov_u64(buffer, pos,

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