From de1439d8a521d22c3219fc007a570fcf944ac789 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 14 Apr 2010 17:44:00 -0300 Subject: [PATCH] perf probe: Support DW_OP_plus_uconst in DW_AT_data_member_location MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Frederic Weisbecker Cc: Ingo Molnar Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-finder.c | 37 +++++++++++++++++++++++++++++----- 1 file changed, 32 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index b4c93659929a..03b469197a03 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -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) { @@ -542,17 +569,17 @@ 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; /* Converting next field */ if (field->next) return convert_variable_fields(die_mem, field->name, - field->next, &ref, die_mem); + field->next, &ref, die_mem); else return 0; }