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fprintf: Show the number of forced alignments in a class 

For instance, for task_struct:

  $ pahole -C task_struct | tail

	/* --- cacheline 104 boundary (6656 bytes) --- */
	struct thread_struct       thread __attribute__((__aligned__(64)); /*  6656  4352 */

	/* size: 11008, cachelines: 172, members: 207 */
	/* sum members: 10902, holes: 16, sum holes: 98 */
	/* sum bitfield members: 10 bits, bit holes: 2, sum bit holes: 54 bits */
	/* paddings: 3, sum paddings: 14 */
	/* forced alignments: 6 */
  };
  $

Cc: Alexei Starovoitov <ast@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Wielaard <mark@klomp.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2019-04-03 13:22:37 -03:00
parent 52d1c75ea4
commit ec772f21f6
1 changed files with 8 additions and 0 deletions
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8
dwarves_fprintf.c
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@ -1231,6 +1231,7 @@ static size_t __class__fprintf(struct class *class, const struct cu *cu,
size_t last_size = 0, size;
uint8_t newline = 0;
uint16_t nr_paddings = 0;
uint16_t nr_forced_alignments = 0;
uint32_t sum_bytes = 0, sum_bits = 0;
uint32_t sum_holes = 0;
uint32_t sum_paddings = 0;
@ -1340,6 +1341,9 @@ static size_t __class__fprintf(struct class *class, const struct cu *cu,
continue;
}
pos = tag__class_member(tag_pos);
if (!cconf.suppress_aligned_attribute && pos->alignment != 0)
++nr_forced_alignments;
/*
* These paranoid checks doesn't make much sense on
* DW_TAG_inheritance, have to understand why virtual public
@ -1550,6 +1554,10 @@ static size_t __class__fprintf(struct class *class, const struct cu *cu,
printed += fprintf(fp, "%.*s/* bit_padding: %u bits */\n",
cconf.indent, tabs,
class->bit_padding);
if (!cconf.suppress_aligned_attribute && nr_forced_alignments != 0)
printed += fprintf(fp, "%.*s/* forced alignments: %u */\n",
cconf.indent, tabs,
nr_forced_alignments);
cacheline = (cconf.base_offset + type->size) % cacheline_size;
if (cacheline != 0)
printed += fprintf(fp, "%.*s/* last cacheline: %u bytes */\n",