diff options
author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-02-22 10:42:55 -0300 |
---|---|---|
committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-02-23 08:50:00 -0300 |
commit | f4c142bb9fe6b02c0af8cfca8a920091e2dba44b (patch) | |
tree | 2b4b576da6835eb847026dad5c1a89c3abf52985 /sysdeps/arm | |
parent | e2a65ecc4b30a797df7dc6529f09b712aa256029 (diff) | |
download | glibc-f4c142bb9fe6b02c0af8cfca8a920091e2dba44b.tar glibc-f4c142bb9fe6b02c0af8cfca8a920091e2dba44b.tar.gz glibc-f4c142bb9fe6b02c0af8cfca8a920091e2dba44b.tar.bz2 glibc-f4c142bb9fe6b02c0af8cfca8a920091e2dba44b.zip |
arm: Use _dl_find_object on __gnu_Unwind_Find_exidx (BZ 31405)
Instead of __dl_iterate_phdr. On ARM dlfo_eh_frame/dlfo_eh_count
maps to PT_ARM_EXIDX vaddr start / length.
On a Neoverse N1 machine with 160 cores, the following program:
$ cat test.c
#include <stdlib.h>
#include <pthread.h>
#include <assert.h>
enum {
niter = 1024,
ntimes = 128,
};
static void *
tf (void *arg)
{
int a = (int) arg;
for (int i = 0; i < niter; i++)
{
void *p[ntimes];
for (int j = 0; j < ntimes; j++)
p[j] = malloc (a * 128);
for (int j = 0; j < ntimes; j++)
free (p[j]);
}
return NULL;
}
int main (int argc, char *argv[])
{
enum { nthreads = 16 };
pthread_t t[nthreads];
for (int i = 0; i < nthreads; i ++)
assert (pthread_create (&t[i], NULL, tf, (void *) i) == 0);
for (int i = 0; i < nthreads; i++)
{
void *r;
assert (pthread_join (t[i], &r) == 0);
assert (r == NULL);
}
return 0;
}
$ arm-linux-gnueabihf-gcc -fsanitize=address test.c -o test
Improves from ~15s to 0.5s.
Checked on arm-linux-gnueabihf.
Diffstat (limited to 'sysdeps/arm')
-rw-r--r-- | sysdeps/arm/find_exidx.c | 57 |
1 files changed, 4 insertions, 53 deletions
diff --git a/sysdeps/arm/find_exidx.c b/sysdeps/arm/find_exidx.c index d647865e5a..a924d59b9f 100644 --- a/sysdeps/arm/find_exidx.c +++ b/sysdeps/arm/find_exidx.c @@ -16,64 +16,15 @@ <https://www.gnu.org/licenses/>. */ #include <link.h> -#include <unwind.h> - -struct unw_eh_callback_data -{ - _Unwind_Ptr pc; - _Unwind_Ptr exidx_start; - int exidx_len; -}; - - -/* Callback to determines if the PC lies within an object, and remember the - location of the exception index table if it does. */ - -static int -find_exidx_callback (struct dl_phdr_info * info, size_t size, void * ptr) -{ - struct unw_eh_callback_data * data; - const ElfW(Phdr) *phdr; - int i; - int match; - _Unwind_Ptr load_base; - - data = (struct unw_eh_callback_data *) ptr; - load_base = info->dlpi_addr; - phdr = info->dlpi_phdr; - - match = 0; - for (i = info->dlpi_phnum; i > 0; i--, phdr++) - { - if (phdr->p_type == PT_LOAD) - { - _Unwind_Ptr vaddr = phdr->p_vaddr + load_base; - if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz) - match = 1; - } - else if (phdr->p_type == PT_ARM_EXIDX) - { - data->exidx_start = (_Unwind_Ptr) (phdr->p_vaddr + load_base); - data->exidx_len = phdr->p_memsz; - } - } - - return match; -} - /* Find the exception index table containing PC. */ _Unwind_Ptr __gnu_Unwind_Find_exidx (_Unwind_Ptr pc, int * pcount) { - struct unw_eh_callback_data data; - - data.pc = pc; - data.exidx_start = 0; - if (__dl_iterate_phdr (find_exidx_callback, &data) <= 0) + struct dl_find_object data; + if (__dl_find_object ((void *) pc, &data) < 0) return 0; - - *pcount = data.exidx_len / 8; - return data.exidx_start; + *pcount = data.dlfo_eh_count; + return (_Unwind_Ptr) data.dlfo_eh_frame; } |