From: Andrii Nakryiko <andriin@xxxxxx>
pahole --reorganize heavily depends on member's bit_hole and hole fields
to denote bit/byte holes *after* member. Previous commit
"dwarves: use bit sizes and bit/byte hole info in __class__fprintf"
changed its meaning to bit/byte hole *before* member to accomodate
possible bit/byte holes at the beginning of a struct. This change broke
reorganization algorithm, though, which is quite involved and isn't
trivially modifiable to accomodate new semantics.
This patch reverts the meaning of bit_hole and hole, but also introduces
per class pre_bit_hole/pre_hole to record initial bit/byte hole of
a struct. This allows to fix reorg code more easily and still handle
initial holes cases, if at the expense of being not as elegant.
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
dwarves.c | 9 ++++--
dwarves.h | 2 ++
dwarves_fprintf.c | 72 +++++++++++++++++++++++++++++++----------------
3 files changed, 57 insertions(+), 26 deletions(-)
diff --git a/dwarves.c b/dwarves.c
index 619dcb3..efa58a9 100644
--- a/dwarves.c
+++ b/dwarves.c
@@ -1260,8 +1260,13 @@ void class__find_holes(struct class *class)
cur_bitfield_end = bit_end;
}
- pos->hole = byte_holes;
- pos->bit_hole = bit_holes;
+ if (last) {
+ last->hole = byte_holes;
+ last->bit_hole = bit_holes;
+ } else {
+ class->pre_hole = byte_holes;
+ class->pre_bit_hole = bit_holes;
+ }
if (bit_holes)
class->nr_bit_holes++;
if (byte_holes)
diff --git a/dwarves.h b/dwarves.h
index e39871f..46083da 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -1026,7 +1026,9 @@ struct class {
uint16_t nr_vtable_entries;
uint8_t nr_holes;
uint8_t nr_bit_holes;
+ uint16_t pre_hole;
uint16_t padding;
+ uint8_t pre_bit_hole;
uint8_t bit_padding;
bool holes_searched;
void *priv;
diff --git a/dwarves_fprintf.c b/dwarves_fprintf.c
index faae3ba..ef53e2b 100644
--- a/dwarves_fprintf.c
+++ b/dwarves_fprintf.c
@@ -1292,6 +1292,30 @@ static size_t __class__fprintf(struct class *class, const struct cu *cu,
printed += fprintf(fp, " {\n");
+ if (class->pre_bit_hole > 0 && !cconf.suppress_comments) {
+ if (!newline++) {
+ fputc('\n', fp);
+ ++printed;
+ }
+ printed += fprintf(fp, "%.*s/* XXX %d bit%s hole, "
+ "try to pack */\n", cconf.indent, tabs,
+ class->pre_bit_hole,
+ class->pre_bit_hole != 1 ? "s" : "");
+ sum_bit_holes += class->pre_bit_hole;
+ }
+
+ if (class->pre_hole > 0 && !cconf.suppress_comments) {
+ if (!newline++) {
+ fputc('\n', fp);
+ ++printed;
+ }
+ printed += fprintf(fp, "%.*s/* XXX %d byte%s hole, "
+ "try to pack */\n",
+ cconf.indent, tabs, class->pre_hole,
+ class->pre_hole != 1 ? "s" : "");
+ sum_holes += class->pre_hole;
+ }
+
type__for_each_tag(type, tag_pos) {
struct tag *type;
const char *accessibility = tag__accessibility(tag_pos);
@@ -1361,30 +1385,6 @@ static size_t __class__fprintf(struct class *class, const struct cu *cu,
}
}
- if (pos->bit_hole != 0 && !cconf.suppress_comments) {
- if (!newline++) {
- fputc('\n', fp);
- ++printed;
- }
- printed += fprintf(fp, "%.*s/* XXX %d bit%s hole, "
- "try to pack */\n", cconf.indent, tabs,
- pos->bit_hole,
- pos->bit_hole != 1 ? "s" : "");
- sum_bit_holes += pos->bit_hole;
- }
-
- if (pos->hole > 0 && !cconf.suppress_comments) {
- if (!newline++) {
- fputc('\n', fp);
- ++printed;
- }
- printed += fprintf(fp, "%.*s/* XXX %d byte%s hole, "
- "try to pack */\n",
- cconf.indent, tabs, pos->hole,
- pos->hole != 1 ? "s" : "");
- sum_holes += pos->hole;
- }
-
if (newline) {
fputc('\n', fp);
newline = 0;
@@ -1428,6 +1428,30 @@ static size_t __class__fprintf(struct class *class, const struct cu *cu,
}
}
+ if (pos->bit_hole != 0 && !cconf.suppress_comments) {
+ if (!newline++) {
+ fputc('\n', fp);
+ ++printed;
+ }
+ printed += fprintf(fp, "\n%.*s/* XXX %d bit%s hole, "
+ "try to pack */", cconf.indent, tabs,
+ pos->bit_hole,
+ pos->bit_hole != 1 ? "s" : "");
+ sum_bit_holes += pos->bit_hole;
+ }
+
+ if (pos->hole > 0 && !cconf.suppress_comments) {
+ if (!newline++) {
+ fputc('\n', fp);
+ ++printed;
+ }
+ printed += fprintf(fp, "\n%.*s/* XXX %d byte%s hole, "
+ "try to pack */",
+ cconf.indent, tabs, pos->hole,
+ pos->hole != 1 ? "s" : "");
+ sum_holes += pos->hole;
+ }
+
fputc('\n', fp);
++printed;
--
2.17.1
