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Eliminate one heap allocation in dwarf_find_debug_frame()

Allocate `tab' from stack in dwarf_find_debug_frame(), as it's only a
few members and we only need it locally in the function.
This commit is contained in:
Tommi Rantala 2012-08-27 13:24:22 +03:00
parent 90d7baea35
commit fce25d74c9

View file

@ -332,18 +332,6 @@ struct debug_frame_tab
uint32_t size;
};
static struct debug_frame_tab *
debug_frame_tab_new (unsigned int base_size)
{
struct debug_frame_tab *tab = malloc (sizeof (struct debug_frame_tab));
tab->tab = calloc (base_size, sizeof (struct table_entry));
tab->length = 0;
tab->size = base_size;
return tab;
}
static void
debug_frame_tab_append (struct debug_frame_tab *tab,
unw_word_t fde_offset, unw_word_t start_ip)
@ -412,7 +400,7 @@ dwarf_find_debug_frame (int found, unw_dyn_info_t *di_debug, unw_word_t ip,
unw_word_t item_start, item_end = 0;
uint32_t u32val = 0;
uint64_t cie_id = 0;
struct debug_frame_tab *tab;
struct debug_frame_tab tab;
Debug (15, "loaded .debug_frame\n");
@ -435,7 +423,9 @@ dwarf_find_debug_frame (int found, unw_dyn_info_t *di_debug, unw_word_t ip,
/* Find all FDE entries in debug_frame, and make into a sorted
index. */
tab = debug_frame_tab_new (16);
tab.length = 0;
tab.size = 16;
tab.tab = calloc (tab.size, sizeof (struct table_entry));
while (addr < (unw_word_t) (uintptr_t) (buf + bufsize))
{
@ -488,7 +478,7 @@ dwarf_find_debug_frame (int found, unw_dyn_info_t *di_debug, unw_word_t ip,
{
Debug (15, "start_ip = %lx, end_ip = %lx\n",
(long) this_pi.start_ip, (long) this_pi.end_ip);
debug_frame_tab_append (tab,
debug_frame_tab_append (&tab,
item_start - (unw_word_t) (uintptr_t) buf,
this_pi.start_ip);
}
@ -499,18 +489,17 @@ dwarf_find_debug_frame (int found, unw_dyn_info_t *di_debug, unw_word_t ip,
addr = item_end;
}
debug_frame_tab_shrink (tab);
qsort (tab->tab, tab->length, sizeof (struct table_entry),
debug_frame_tab_shrink (&tab);
qsort (tab.tab, tab.length, sizeof (struct table_entry),
debug_frame_tab_compare);
/* for (i = 0; i < tab->length; i++)
/* for (i = 0; i < tab.length; i++)
{
fprintf (stderr, "ip %x, fde offset %x\n",
(int) tab->tab[i].start_ip_offset,
(int) tab->tab[i].fde_offset);
(int) tab.tab[i].start_ip_offset,
(int) tab.tab[i].fde_offset);
}*/
fdesc->index = tab->tab;
fdesc->index_size = tab->length;
free (tab);
fdesc->index = tab.tab;
fdesc->index_size = tab.length;
}
di->format = UNW_INFO_FORMAT_TABLE;