diff options
author | Masami Hiramatsu <mhiramat@kernel.org> | 2018-03-17 21:52:25 +0900 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-03-19 13:51:53 -0300 |
commit | d0461794a1dcaf552b507e23788777f718b736a1 (patch) | |
tree | 3b11b356462ccadfc2b64b974f2af8cb6bb93ed0 /tools/perf/util | |
parent | 4c9cb2c2b4b5530717f74b2252f8cc4c45b2a918 (diff) | |
download | op-kernel-dev-d0461794a1dcaf552b507e23788777f718b736a1.zip op-kernel-dev-d0461794a1dcaf552b507e23788777f718b736a1.tar.gz |
perf probe: Use right type to access array elements
Current 'perf probe' converts the type of array-elements incorrectly. It
always converts the types as a pointer of array. This passes the "array"
type DIE to the type converter so that it can get correct "element of
array" type DIE from it.
E.g.
====
$ cat hello.c
#include <stdio.h>
void foo(int a[])
{
printf("%d\n", a[1]);
}
void main()
{
int a[3] = {4, 5, 6};
printf("%d\n", a[0]);
foo(a);
}
$ gcc -g hello.c -o hello
$ perf probe -x ./hello -D "foo a[1]"
====
Without this fix, above outputs
====
p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):u64
====
The "u64" means "int *", but a[1] is "int".
With this,
====
p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):s32
====
So, "int" correctly converted to "s32"
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: linux-kselftest@vger.kernel.org
Cc: linux-trace-users@vger.kernel.org
Fixes: b2a3c12b7442 ("perf probe: Support tracing an entry of array")
Link: http://lkml.kernel.org/r/152129114502.31874.2474068470011496356.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util')
-rw-r--r-- | tools/perf/util/probe-finder.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index a5731de..c37fbef 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -423,20 +423,20 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } - pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type)); + pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type), + (unsigned)dwarf_dieoffset(&type)); tag = dwarf_tag(&type); if (field->name[0] == '[' && (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) { - if (field->next) - /* Save original type for next field */ - memcpy(die_mem, &type, sizeof(*die_mem)); + /* Save original type for next field or type */ + memcpy(die_mem, &type, sizeof(*die_mem)); /* Get the type of this array */ if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } - pr_debug2("Array real type: (%x)\n", + pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type), (unsigned)dwarf_dieoffset(&type)); if (tag == DW_TAG_pointer_type) { ref = zalloc(sizeof(struct probe_trace_arg_ref)); @@ -448,9 +448,6 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, *ref_ptr = ref; } ref->offset += dwarf_bytesize(&type) * field->index; - if (!field->next) - /* Save vr_die for converting types */ - memcpy(die_mem, vr_die, sizeof(*die_mem)); goto next; } else if (tag == DW_TAG_pointer_type) { /* Check the pointer and dereference */ |