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perf probe: Support DW_OP_plus_uconst in DW_AT_data_member_location

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DW_OP_plus_uconst can be used for DW_AT_data_member_location.
This patch adds DW_OP_plus_uconst support when getting
structure member offset.

Commiter note:

Fixed up the size_t format specifier in one case:

cc1: warnings being treated as errors
util/probe-finder.c: In function ‘die_get_data_member_location’:
util/probe-finder.c:270: error: format ‘%d’ expects type ‘int’, but argument 4 has type ‘size_t’
make: *** [/home/acme/git/build/perf/util/probe-finder.o] Error 1

LKML-Reference: <20100414223958.14630.5230.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2010-04-14 17:44:00 -03:00 committed by Arnaldo Carvalho de Melo
parent dda4ab34fe
commit de1439d8a5
1 changed files with 32 additions and 5 deletions
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35
tools/perf/util/probe-finder.c
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@ -249,6 +249,33 @@ static int die_get_byte_size(Dwarf_Die *tp_die)
return (int)ret; return (int)ret;
} }
/* Get data_member_location offset */
static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
{
Dwarf_Attribute attr;
Dwarf_Op *expr;
size_t nexpr;
int ret;
if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
return -ENOENT;
if (dwarf_formudata(&attr, offs) != 0) {
/* DW_AT_data_member_location should be DW_OP_plus_uconst */
ret = dwarf_getlocation(&attr, &expr, &nexpr);
if (ret < 0 || nexpr == 0)
return -ENOENT;
if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
expr[0].atom, nexpr);
return -ENOTSUP;
}
*offs = (Dwarf_Word)expr[0].number;
}
return 0;
}
/* Return values for die_find callbacks */ /* Return values for die_find callbacks */
enum { enum {
DIE_FIND_CB_FOUND = 0, /* End of Search */ DIE_FIND_CB_FOUND = 0, /* End of Search */
@ -482,9 +509,9 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
Dwarf_Die *die_mem) Dwarf_Die *die_mem)
{ {
struct kprobe_trace_arg_ref *ref = *ref_ptr; struct kprobe_trace_arg_ref *ref = *ref_ptr;
Dwarf_Attribute attr;
Dwarf_Die type; Dwarf_Die type;
Dwarf_Word offs; Dwarf_Word offs;
int ret;
pr_debug("converting %s in %s\n", field->name, varname); pr_debug("converting %s in %s\n", field->name, varname);
if (die_get_real_type(vr_die, &type) == NULL) { if (die_get_real_type(vr_die, &type) == NULL) {
@ -542,10 +569,10 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
} }
/* Get the offset of the field */ /* Get the offset of the field */
if (dwarf_attr(die_mem, DW_AT_data_member_location, &attr) == NULL || ret = die_get_data_member_location(die_mem, &offs);
dwarf_formudata(&attr, &offs) != 0) { if (ret < 0) {
pr_warning("Failed to get the offset of %s.\n", field->name); pr_warning("Failed to get the offset of %s.\n", field->name);
return -ENOENT; return ret;
} }
ref->offset += (long)offs; ref->offset += (long)offs;