From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05AE0335C7; Sat, 30 Aug 2025 01:22:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756516956; cv=none; b=Lvte3qjnHw8ntD8OapJO7yL8oXT6gAe0a9sfg8i7WF0zA0LbF0UcOW3JWQtx2oNYIcAActACNp0Ngl5xpCo26EF2E4DeZGKGb2QNUuFyYXkz3RpExweZn4bS+ouXUBITPVHT5D1+RlGH182hekIoz/YpjkI/oR9+eVrp2k5HIzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756516956; c=relaxed/simple; bh=qOurC+VJB+2ixWBbyJM/u92wS1KcJxbfjFpqm3Cc684=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I2bf1JlVhby3aSuMwnXuei0/JHrixpjtIEbV2sDCyqXVllqHNaJ0Kld31a16zNQtMkaEMcQHd2y+++K6a+mBrF7R+lboQKYt6RRebJlxgIdDwuUdae8PJFwWrgxWmUQ2LVckbePwePIUpJpE3PR7Of/l+ro4AS5t+/y19r6Ies0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YNJQ2H3R; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YNJQ2H3R" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5C35C4CEF0; Sat, 30 Aug 2025 01:22:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756516955; bh=qOurC+VJB+2ixWBbyJM/u92wS1KcJxbfjFpqm3Cc684=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YNJQ2H3R3QrjSLAOUimiwD/yquKQrJ4yqY4Zj/axKpRUHhtDtpNTdxNZADyV6jMf0 atSLurelIpS6rRfjmaUSfR12FyJPJX/1rw6Qb3/QhiVHpU/VliDrhle3EHg83Cv60G w3KRtgUq+O97/L3b1j9vfFgfbetdnMG36Ii92F1BZiyJBNUQjS/dWkB6VjMpgSKWzu edVuM/jHpiCqFsyMcznjZ8drBtDX6CC70BWergPKMRpY/KgmRWR01YbAntc37W/DLK 7KnozHrBaKYrHIJ5nhH3wuzh97psDgCWQbCmkzlar+et+H6Ucj7UoJYv89E09yjqzk iO/N58XzvJDEw== Date: Fri, 29 Aug 2025 18:22:33 -0700 From: Namhyung Kim To: Zecheng Li Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Masami Hiramatsu , Xu Liu , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 03/10] perf dwarf-aux: Better variable collection for insn tracking Message-ID: References: <20250825195412.223077-1-zecheng@google.com> <20250825195412.223077-4-zecheng@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250825195412.223077-4-zecheng@google.com> On Mon, Aug 25, 2025 at 07:54:05PM +0000, Zecheng Li wrote: > Utilizes the previous is_breg_access_indirect function to determine if > the register + offset stores the variable itself or the struct it points > to, save the information in die_var_type.is_reg_var_addr. > > Since we are storing the real types in the stack state, we need to do a > type dereference when is_reg_var_addr is set to false for stack/frame > registers. > > For other gp registers, skip the variable when the register is a pointer > to the type. If we want to accept these variables, we might also utilize > is_reg_var_addr in a different way, we need to mark that register as a > pointer to the type. > > Signed-off-by: Zecheng Li Reviewed-by: Namhyung Kim Thanks, Namhyung > --- > tools/perf/util/annotate-data.c | 9 +++++++++ > tools/perf/util/dwarf-aux.c | 11 ++++++++++- > tools/perf/util/dwarf-aux.h | 2 ++ > 3 files changed, 21 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c > index 1ef2edbc71d9..258157cc43c2 100644 > --- a/tools/perf/util/annotate-data.c > +++ b/tools/perf/util/annotate-data.c > @@ -868,6 +868,11 @@ static void update_var_state(struct type_state *state, struct data_loc_info *dlo > int offset = var->offset; > struct type_state_stack *stack; > > + /* If the reg location holds the pointer value, dereference the type */ > + if (!var->is_reg_var_addr && is_pointer_type(&mem_die) && > + __die_get_real_type(&mem_die, &mem_die) == NULL) > + continue; > + > if (var->reg != DWARF_REG_FB) > offset -= fb_offset; > > @@ -893,6 +898,10 @@ static void update_var_state(struct type_state *state, struct data_loc_info *dlo > > reg = &state->regs[var->reg]; > > + /* For gp registers, skip the address registers for now */ > + if (var->is_reg_var_addr) > + continue; > + > if (reg->ok && reg->kind == TSR_KIND_TYPE && > !is_better_type(®->type, &mem_die)) > continue; > diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c > index 449bc9ad7aff..6fd2db5d9381 100644 > --- a/tools/perf/util/dwarf-aux.c > +++ b/tools/perf/util/dwarf-aux.c > @@ -1627,13 +1627,22 @@ static int __die_collect_vars_cb(Dwarf_Die *die_mem, void *arg) > if (!check_allowed_ops(ops, nops)) > return DIE_FIND_CB_SIBLING; > > - if (die_get_real_type(die_mem, &type_die) == NULL) > + if (__die_get_real_type(die_mem, &type_die) == NULL) > return DIE_FIND_CB_SIBLING; > > vt = malloc(sizeof(*vt)); > if (vt == NULL) > return DIE_FIND_CB_END; > > + /* Usually a register holds the value of a variable */ > + vt->is_reg_var_addr = false; > + > + if (((ops->atom >= DW_OP_breg0 && ops->atom <= DW_OP_breg31) || > + ops->atom == DW_OP_bregx || ops->atom == DW_OP_fbreg) && > + !is_breg_access_indirect(ops, nops)) > + /* The register contains an address of the variable. */ > + vt->is_reg_var_addr = true; > + > vt->die_off = dwarf_dieoffset(&type_die); > vt->addr = start; > vt->reg = reg_from_dwarf_op(ops); > diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h > index 892c8c5c23fc..cd481ec9c5a1 100644 > --- a/tools/perf/util/dwarf-aux.h > +++ b/tools/perf/util/dwarf-aux.h > @@ -148,6 +148,8 @@ struct die_var_type { > u64 addr; > int reg; > int offset; > + /* Whether the register holds a address to the type */ > + bool is_reg_var_addr; > }; > > /* Return type info of a member at offset */ > -- > 2.51.0.261.g7ce5a0a67e-goog >