perf probe: Add bitfield member support

Add bitfield member accessing support to probe arguments.

Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20110204125211.9507.60265.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ committer note: Fixed up '%lu' use for return of BYTES_TO_BITS ('%zd') ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2011-02-04 21:52:11 +09:00 committed by Arnaldo Carvalho de Melo
parent a222179625
commit 124bb83cd7

View file

@ -33,6 +33,7 @@
#include <ctype.h>
#include <dwarf-regs.h>
#include <linux/bitops.h>
#include "event.h"
#include "debug.h"
#include "util.h"
@ -333,13 +334,23 @@ static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
return vr_die;
}
static bool die_is_signed_type(Dwarf_Die *tp_die)
static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
Dwarf_Word *result)
{
Dwarf_Attribute attr;
if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
dwarf_formudata(&attr, result) != 0)
return -ENOENT;
return 0;
}
static bool die_is_signed_type(Dwarf_Die *tp_die)
{
Dwarf_Word ret;
if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
dwarf_formudata(&attr, &ret) != 0)
if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
return false;
return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
@ -348,11 +359,29 @@ static bool die_is_signed_type(Dwarf_Die *tp_die)
static int die_get_byte_size(Dwarf_Die *tp_die)
{
Dwarf_Attribute attr;
Dwarf_Word ret;
if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
dwarf_formudata(&attr, &ret) != 0)
if (die_get_attr_udata(tp_die, DW_AT_byte_size, &ret))
return 0;
return (int)ret;
}
static int die_get_bit_size(Dwarf_Die *tp_die)
{
Dwarf_Word ret;
if (die_get_attr_udata(tp_die, DW_AT_bit_size, &ret))
return 0;
return (int)ret;
}
static int die_get_bit_offset(Dwarf_Die *tp_die)
{
Dwarf_Word ret;
if (die_get_attr_udata(tp_die, DW_AT_bit_offset, &ret))
return 0;
return (int)ret;
@ -827,6 +856,8 @@ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
return 0;
}
#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
static int convert_variable_type(Dwarf_Die *vr_die,
struct probe_trace_arg *tvar,
const char *cast)
@ -843,6 +874,14 @@ static int convert_variable_type(Dwarf_Die *vr_die,
return (tvar->type == NULL) ? -ENOMEM : 0;
}
if (die_get_bit_size(vr_die) != 0) {
/* This is a bitfield */
ret = snprintf(buf, 16, "b%d@%d/%zd", die_get_bit_size(vr_die),
die_get_bit_offset(vr_die),
BYTES_TO_BITS(die_get_byte_size(vr_die)));
goto formatted;
}
if (die_get_real_type(vr_die, &type) == NULL) {
pr_warning("Failed to get a type information of %s.\n",
dwarf_diename(vr_die));
@ -887,29 +926,31 @@ static int convert_variable_type(Dwarf_Die *vr_die,
return (tvar->type == NULL) ? -ENOMEM : 0;
}
ret = die_get_byte_size(&type) * 8;
if (ret) {
/* Check the bitwidth */
if (ret > MAX_BASIC_TYPE_BITS) {
pr_info("%s exceeds max-bitwidth."
" Cut down to %d bits.\n",
dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
ret = MAX_BASIC_TYPE_BITS;
}
ret = BYTES_TO_BITS(die_get_byte_size(&type));
if (!ret)
/* No size ... try to use default type */
return 0;
ret = snprintf(buf, 16, "%c%d",
die_is_signed_type(&type) ? 's' : 'u', ret);
if (ret < 0 || ret >= 16) {
if (ret >= 16)
ret = -E2BIG;
pr_warning("Failed to convert variable type: %s\n",
strerror(-ret));
return ret;
}
tvar->type = strdup(buf);
if (tvar->type == NULL)
return -ENOMEM;
/* Check the bitwidth */
if (ret > MAX_BASIC_TYPE_BITS) {
pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
ret = MAX_BASIC_TYPE_BITS;
}
ret = snprintf(buf, 16, "%c%d",
die_is_signed_type(&type) ? 's' : 'u', ret);
formatted:
if (ret < 0 || ret >= 16) {
if (ret >= 16)
ret = -E2BIG;
pr_warning("Failed to convert variable type: %s\n",
strerror(-ret));
return ret;
}
tvar->type = strdup(buf);
if (tvar->type == NULL)
return -ENOMEM;
return 0;
}