From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 88355 invoked by alias); 29 May 2017 23:19:14 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 88339 invoked by uid 89); 29 May 2017 23:19:13 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.7 required=5.0 tests=AWL,BAYES_00,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=ham version=3.3.2 spammy=Alan X-HELO: gproxy7.mail.unifiedlayer.com Received: from gproxy7-pub.mail.unifiedlayer.com (HELO gproxy7.mail.unifiedlayer.com) (70.40.196.235) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 29 May 2017 23:19:12 +0000 Received: from CMOut01 (unknown [10.0.90.82]) by gproxy7.mail.unifiedlayer.com (Postfix) with ESMTP id 97306215D91 for ; Mon, 29 May 2017 17:19:14 -0600 (MDT) Received: from box522.bluehost.com ([74.220.219.122]) by CMOut01 with id SPKB1v00A2f2jeq01PKEjS; Mon, 29 May 2017 17:19:14 -0600 X-Authority-Analysis: v=2.2 cv=K+5SJ2eI c=1 sm=1 tr=0 a=GsOEXm/OWkKvwdLVJsfwcA==:117 a=GsOEXm/OWkKvwdLVJsfwcA==:17 a=tJ8p9aeEuA8A:10 a=zstS-IiYAAAA:8 a=NEAV23lmAAAA:8 a=7CQSdrXTAAAA:8 a=mDV3o1hIAAAA:8 a=ETNSbJok8jvZRx5IRPIA:9 a=8XN2G1YXvw_O3EXF:21 a=YdWgIixRSKmyZ0Hr:21 a=4G6NA9xxw8l3yy4pmD5M:22 a=a-qgeE7W1pNrGK8U0ZQC:22 a=_FVE-zBwftR9WsbkzFJk:22 Received: from 174-29-43-217.hlrn.qwest.net ([174.29.43.217]:54946 helo=bapiya) by box522.bluehost.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1dFTwN-0006nz-7d; Mon, 29 May 2017 17:19:11 -0600 From: Tom Tromey To: Simon Marchi Cc: Tom Tromey , gdb-patches@sourceware.org Subject: Re: [RFA] Fix size check in dwarf2_evaluate_loc_desc_full References: <20170529162544.8652-1-tom@tromey.com> Date: Mon, 29 May 2017 23:19:00 -0000 In-Reply-To: (Simon Marchi's message of "Mon, 29 May 2017 22:55:33 +0200") Message-ID: <8760gjckuq.fsf@bapiya> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-BWhitelist: no X-Exim-ID: 1dFTwN-0006nz-7d X-Source-Sender: 174-29-43-217.hlrn.qwest.net (bapiya) [174.29.43.217]:54946 X-Source-Auth: tom+tromey.com X-Email-Count: 2 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTIyLmJsdWVob3N0LmNvbQ== X-SW-Source: 2017-05/txt/msg00610.txt.bz2 Simon> Would it be possible to test the error case as well by feeding bad Simon> DWARF info in the test case? Sure, here it is. Tom commit 51762c8cfa3a0b7203032db42b97ad51c188602b Author: Tom Tromey Date: Sun May 28 08:06:54 2017 -0600 Fix size check in dwarf2_evaluate_loc_desc_full This Rust bug report: https://github.com/rust-lang/rust/issues/41970 noted an error from gdb. What is happening here (for me, the original report had a different error) is that a pieced DWARF expression is not writing to every byte in the resulting value. GDB errors in this case. However, it seems to me that it is always valid to write fewer bytes; the issue comes from writing too many -- that is, the test is reversed. The test was also checking the sub-object, but this also seems incorrect, as it's expected for the expression to write the entirety of the enclosing object. So, this patch reverses the test and applies it to the outer type, not the subobject type. Regtested on the buildbot. ChangeLog 2017-05-29 Tom Tromey * dwarf2loc.c (dwarf2_evaluate_loc_desc_full): Reverse size check and apply to outer type. testsuite/ChangeLog 2017-05-29 Tom Tromey * gdb.dwarf2/shortpiece.exp: New file. diff --git a/gdb/ChangeLog b/gdb/ChangeLog index fd52229..e331f4a 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2017-05-29 Tom Tromey + + * dwarf2loc.c (dwarf2_evaluate_loc_desc_full): Reverse size + check and apply to outer type. + 2017-05-26 Alan Hayward * defs.h (copy_integer_to_size): New declaration. diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index 127167d..9ffe197 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -2407,7 +2407,9 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame, for (i = 0; i < ctx.num_pieces; ++i) bit_size += ctx.pieces[i].size; - if (8 * (subobj_byte_offset + TYPE_LENGTH (subobj_type)) > bit_size) + /* Complain if the expression is larger than the size of the + outer type. */ + if (bit_size > 8 * TYPE_LENGTH (type)) invalid_synthetic_pointer (); c = allocate_piece_closure (per_cu, ctx.num_pieces, ctx.pieces, diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index c16f201..d31679a 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2017-05-29 Tom Tromey + + * gdb.dwarf2/shortpiece.exp: New file. + 2017-05-21 Tom Tromey PR rust/21466: diff --git a/gdb/testsuite/gdb.dwarf2/shortpiece.exp b/gdb/testsuite/gdb.dwarf2/shortpiece.exp new file mode 100644 index 0000000..8526a70 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/shortpiece.exp @@ -0,0 +1,100 @@ +# Copyright 2017 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +load_lib dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +if {![dwarf2_support]} { + return 0 +} + +standard_testfile main.c shortpiece-dw.S + +# Make some DWARF for the test. +set asm_file [standard_output_file $srcfile2] +Dwarf::assemble $asm_file { + global pair + + cu { addr_size 4 } { + compile_unit {} { + declare_labels int_label ushort_label struct_label + + int_label: DW_TAG_base_type { + {DW_AT_byte_size 4 DW_FORM_udata} + {DW_AT_encoding @DW_ATE_unsigned} + {DW_AT_name "myint"} + } + ushort_label: DW_TAG_base_type { + {DW_AT_byte_size 2 DW_FORM_udata} + {DW_AT_encoding @DW_ATE_unsigned} + {DW_AT_name "myushort"} + } + + struct_label: DW_TAG_structure_type { + {DW_AT_name "S"} + {DW_AT_byte_size 8 DW_FORM_udata} + } { + DW_TAG_member { + {DW_AT_name "a"} + {DW_AT_type :${int_label}} + {DW_AT_data_member_location 0 DW_FORM_udata} + } + + DW_TAG_member { + {DW_AT_name "b"} + {DW_AT_type :${ushort_label}} + {DW_AT_data_member_location 4 DW_FORM_udata} + } + } + + DW_TAG_variable { + {DW_AT_name "s1"} + {DW_AT_type :${struct_label}} + {DW_AT_external 1 DW_FORM_flag} + {DW_AT_location { + DW_OP_constu 1 + DW_OP_stack_value + DW_OP_piece 4 + DW_OP_constu 0 + DW_OP_stack_value + DW_OP_piece 2 + } SPECIAL_expr} + } + + DW_TAG_variable { + {DW_AT_name "s2"} + {DW_AT_type :${struct_label}} + {DW_AT_external 1 DW_FORM_flag} + {DW_AT_location { + DW_OP_constu 1 + DW_OP_stack_value + DW_OP_piece 4 + DW_OP_constu 0 + DW_OP_stack_value + DW_OP_piece 8 + } SPECIAL_expr} + } + } + } +} + +if { [prepare_for_testing "failed to prepare" ${testfile} \ + [list $srcfile $asm_file] {nodebug}] } { + return -1 +} + +gdb_test "p s1" " = {a = 1, b = 0}" +gdb_test "p s2" \ + "access outside bounds of object referenced via synthetic pointer"