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Commit de1439d8 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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perf probe: Support DW_OP_plus_uconst in DW_AT_data_member_location 



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: default avatarMasami 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent dda4ab34

tools/perf/util/probe-finder.c

+32 −5
Original line number Diff line number Diff line
@@ -249,6 +249,33 @@ static int die_get_byte_size(Dwarf_Die *tp_die) 
	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 */

enum {

	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)

{

	struct kprobe_trace_arg_ref *ref = *ref_ptr;

	Dwarf_Attribute attr;

	Dwarf_Die type;

	Dwarf_Word offs;

	int ret;



	pr_debug("converting %s in %s\n", field->name, varname);

	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 */

	if (dwarf_attr(die_mem, DW_AT_data_member_location, &attr) == NULL ||

	    dwarf_formudata(&attr, &offs) != 0) {

	ret = die_get_data_member_location(die_mem, &offs);

	if (ret < 0) {

		pr_warning("Failed to get the offset of %s.\n", field->name);

		return -ENOENT;

		return ret;

	}

	ref->offset += (long)offs;