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perf probe: Support "string" type

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Support string type casting to event argument. If perf-probe finds an argument
casted as string, it ensures the target variable is "(unsigned/signed) char
*(or []). perf-probe also adds dereference if the target is a pointer.

So, both of 'char buf[10];' and 'char *buf;' can be accessed by 'buf:string'

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100519195734.2885.1666.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu
2010-05-19 15:57:35 -04:00
committed by Arnaldo Carvalho de Melo
parent e09c8614b3
commit 73317b9540
2 changed files with 49 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
tools/perf/util/probe-finder.c
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@@ -464,18 +464,61 @@ static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
}
static int convert_variable_type(Dwarf_Die *vr_die,
struct kprobe_trace_arg *targ)
struct kprobe_trace_arg *tvar,
const char *cast)
{
struct kprobe_trace_arg_ref **ref_ptr = &tvar->ref;
Dwarf_Die type;
char buf[16];
int ret;
/* TODO: check all types */
if (cast && strcmp(cast, "string") != 0) {
/* Non string type is OK */
tvar->type = strdup(cast);
return (tvar->type == NULL) ? -ENOMEM : 0;
}
if (die_get_real_type(vr_die, &type) == NULL) {
pr_warning("Failed to get a type information of %s.\n",
dwarf_diename(vr_die));
return -ENOENT;
}
if (cast && strcmp(cast, "string") == 0) { /* String type */
ret = dwarf_tag(&type);
if (ret != DW_TAG_pointer_type &&
ret != DW_TAG_array_type) {
pr_warning("Failed to cast into string: "
"%s(%s) is not a pointer nor array.",
dwarf_diename(vr_die), dwarf_diename(&type));
return -EINVAL;
}
if (ret == DW_TAG_pointer_type) {
if (die_get_real_type(&type, &type) == NULL) {
pr_warning("Failed to get a type information.");
return -ENOENT;
}
while (*ref_ptr)
ref_ptr = &(*ref_ptr)->next;
/* Add new reference with offset +0 */
*ref_ptr = zalloc(sizeof(struct kprobe_trace_arg_ref));
if (*ref_ptr == NULL) {
pr_warning("Out of memory error\n");
return -ENOMEM;
}
}
if (die_compare_name(&type, "char") != 0 &&
die_compare_name(&type, "unsigned char") != 0) {
pr_warning("Failed to cast into string: "
"%s is not (unsigned) char *.",
dwarf_diename(vr_die));
return -EINVAL;
}
tvar->type = strdup(cast);
return (tvar->type == NULL) ? -ENOMEM : 0;
}
ret = die_get_byte_size(&type) * 8;
if (ret) {
/* Check the bitwidth */
@@ -495,8 +538,8 @@ static int convert_variable_type(Dwarf_Die *vr_die,
strerror(-ret));
return ret;
}
targ->type = strdup(buf);
if (targ->type == NULL)
tvar->type = strdup(buf);
if (tvar->type == NULL)
return -ENOMEM;
}
return 0;
@@ -606,14 +649,8 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
&die_mem);
vr_die = &die_mem;
}
if (ret == 0) {
if (pf->pvar->type) {
pf->tvar->type = strdup(pf->pvar->type);
if (pf->tvar->type == NULL)
ret = -ENOMEM;
} else
ret = convert_variable_type(vr_die, pf->tvar);
}
if (ret == 0)
ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
/* *expr will be cached in libdw. Don't free it. */
return ret;
error: