From patchwork Fri Apr 7 17:38:10 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Arnez X-Patchwork-Id: 19897 Received: (qmail 59641 invoked by alias); 7 Apr 2017 17:41:08 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 59597 invoked by uid 89); 7 Apr 2017 17:41:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.2 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_LAZY_DOMAIN_SECURITY, RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.2 spammy= X-HELO: mx0a-001b2d01.pphosted.com Received: from mx0a-001b2d01.pphosted.com (HELO mx0a-001b2d01.pphosted.com) (148.163.156.1) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 07 Apr 2017 17:41:06 +0000 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v37HcfDW061114 for ; Fri, 7 Apr 2017 13:41:07 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 29nsrbpfn7-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 07 Apr 2017 13:41:06 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 7 Apr 2017 18:41:01 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v37Hf0XV38928604 for ; Fri, 7 Apr 2017 17:41:00 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 012E111C050 for ; Fri, 7 Apr 2017 18:40:22 +0100 (BST) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DABB611C04C for ; Fri, 7 Apr 2017 18:40:21 +0100 (BST) Received: from oc1027705133.ibm.com (unknown [9.152.212.162]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP for ; Fri, 7 Apr 2017 18:40:21 +0100 (BST) From: Andreas Arnez To: gdb-patches@sourceware.org Subject: [PATCH 3/9] PR gdb/21226: Take DWARF stack value pieces from LSB end Date: Fri, 7 Apr 2017 19:38:10 +0200 In-Reply-To: <1491586736-21296-1-git-send-email-arnez@linux.vnet.ibm.com> References: <1491586736-21296-1-git-send-email-arnez@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17040717-0040-0000-0000-00000380A887 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17040717-0041-0000-0000-00001F9C8A29 Message-Id: <1491586736-21296-4-git-send-email-arnez@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-04-07_15:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1704070144 X-IsSubscribed: yes When taking a DW_OP_piece or DW_OP_bit_piece from a DW_OP_stack_value, the existing logic always takes the piece from the lowest-addressed end, which is wrong on big-endian targets. The DWARF standard states that the "DW_OP_bit_piece operation describes a sequence of bits using the least significant bits of that value", and this also matches the current logic in GCC. For instance, the GCC guality test case pr54970.c fails on s390x because of this. This fix adjusts the piece accordingly on big-endian targets. It is assumed that: * DW_OP_piece shall take the piece from the LSB end as well; * pieces reaching outside the stack value bits are considered undefined, and a zero value can be used instead. gdb/ChangeLog: PR gdb/21226 * dwarf2loc.c (read_pieced_value): Anchor stack value pieces at the LSB end, independent of endianness. gdb/testsuite/ChangeLog: PR gdb/21226 * gdb.dwarf2/nonvar-access.exp: Add checks for verifying that stack value pieces are taken from the LSB end. --- gdb/dwarf2loc.c | 43 ++++++++++++++++-------------- gdb/testsuite/gdb.dwarf2/nonvar-access.exp | 21 ++++++++++++--- 2 files changed, 41 insertions(+), 23 deletions(-) diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index 496400a..09938c4 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -1857,6 +1857,10 @@ read_pieced_value (struct value *v) if (unavail) mark_value_bits_unavailable (v, offset, this_size_bits); } + + copy_bitwise (contents, dest_offset_bits, + intermediate_buffer, source_offset_bits % 8, + this_size_bits, bits_big_endian); } break; @@ -1865,26 +1869,28 @@ read_pieced_value (struct value *v) p->v.mem.in_stack_memory, p->v.mem.addr + source_offset, buffer.data (), this_size); + copy_bitwise (contents, dest_offset_bits, + intermediate_buffer, source_offset_bits % 8, + this_size_bits, bits_big_endian); break; case DWARF_VALUE_STACK: { - size_t n = this_size; + struct objfile *objfile = dwarf2_per_cu_objfile (c->per_cu); + struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile); + ULONGEST obj_size = 8 * TYPE_LENGTH (value_type (p->v.value)); - if (n > c->addr_size - source_offset) - n = (c->addr_size >= source_offset - ? c->addr_size - source_offset - : 0); - if (n == 0) - { - /* Nothing. */ - } - else - { - const gdb_byte *val_bytes = value_contents_all (p->v.value); + /* Use zeroes if piece reaches beyond stack value. */ + if (p->size > obj_size) + break; - intermediate_buffer = val_bytes + source_offset; - } + /* Piece is anchored at least significant bit end. */ + if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG) + source_offset_bits += obj_size - p->size; + copy_bitwise (contents, dest_offset_bits, + value_contents_all (p->v.value), + source_offset_bits, + this_size_bits, bits_big_endian); } break; @@ -1898,6 +1904,9 @@ read_pieced_value (struct value *v) : 0); if (n != 0) intermediate_buffer = p->v.literal.data + source_offset; + copy_bitwise (contents, dest_offset_bits, + intermediate_buffer, source_offset_bits % 8, + this_size_bits, bits_big_endian); } break; @@ -1914,12 +1923,6 @@ read_pieced_value (struct value *v) internal_error (__FILE__, __LINE__, _("invalid location type")); } - if (p->location != DWARF_VALUE_OPTIMIZED_OUT - && p->location != DWARF_VALUE_IMPLICIT_POINTER) - copy_bitwise (contents, dest_offset_bits, - intermediate_buffer, source_offset_bits % 8, - this_size_bits, bits_big_endian); - offset += this_size_bits; } } diff --git a/gdb/testsuite/gdb.dwarf2/nonvar-access.exp b/gdb/testsuite/gdb.dwarf2/nonvar-access.exp index 99f63cc..5406029 100644 --- a/gdb/testsuite/gdb.dwarf2/nonvar-access.exp +++ b/gdb/testsuite/gdb.dwarf2/nonvar-access.exp @@ -128,14 +128,26 @@ Dwarf::assemble $asm_file { {name def_t} {type :$struct_t_label} {location { - const1u 0 + const2s -184 stack_value bit_piece 9 0 - const1s -1 + const4u 1752286 stack_value bit_piece 23 0 } SPECIAL_expr} } + # Composite location with some empty pieces. + DW_TAG_variable { + {name part_def_a} + {type :$array_a9_label} + {location { + piece 3 + const4u 0xf1927314 + stack_value + piece 4 + piece 2 + } SPECIAL_expr} + } # Implicit location: immediate value. DW_TAG_variable { {name def_implicit_s} @@ -221,9 +233,12 @@ gdb_test "print/x *implicit_b_ptr" " = $val" # Byte-aligned fields, pieced together from DWARF stack values. gdb_test "print def_s" " = \\{a = 0, b = -1\\}" +switch $endian { big {set val 0x92} little {set val 0x73} } +gdb_test "print/x part_def_a\[4\]" " = $val" +gdb_test "print/x part_def_a\[8\]" " = " # Non-byte-aligned fields, pieced together from DWARF stack values. -gdb_test "print def_t" " = \\{a = 0, b = -1\\}" +gdb_test "print def_t" " = \\{a = -184, b = 1752286\\}" # Simple variable without location. gdb_test "print undef_int" " = "