From patchwork Tue May 9 17:45:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Arnez X-Patchwork-Id: 20339 Received: (qmail 64225 invoked by alias); 9 May 2017 17:49:05 -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 64210 invoked by uid 89); 9 May 2017 17:49:05 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.4 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=zeroes, Composite, reaches 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; Tue, 09 May 2017 17:49:03 +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 v49HluQi127096 for ; Tue, 9 May 2017 13:49:05 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0a-001b2d01.pphosted.com with ESMTP id 2abcjksc7x-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 09 May 2017 13:49:04 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Tue, 9 May 2017 18:48:59 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v49Hmx9b38535372 for ; Tue, 9 May 2017 17:48:59 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D03B652041 for ; Tue, 9 May 2017 17:46:22 +0100 (BST) Received: from oc1027705133.ibm.com (unknown [9.152.212.109]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id ACE1F5203F for ; Tue, 9 May 2017 17:46:22 +0100 (BST) From: Andreas Arnez To: gdb-patches@sourceware.org Subject: [PATCH v2 03/19] PR gdb/21226: Take DWARF stack value pieces from LSB end Date: Tue, 9 May 2017 19:45:59 +0200 In-Reply-To: <1494352015-10465-1-git-send-email-arnez@linux.vnet.ibm.com> References: <1494352015-10465-1-git-send-email-arnez@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17050917-0012-0000-0000-00000526C561 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17050917-0013-0000-0000-00001865B1D9 Message-Id: <1494352015-10465-4-git-send-email-arnez@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-05-09_14:, , 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=8.0.1-1703280000 definitions=main-1705090097 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 | 46 +++++++++++++++++------------- gdb/testsuite/gdb.dwarf2/nonvar-access.exp | 21 ++++++++++++-- 2 files changed, 44 insertions(+), 23 deletions(-) diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index 2a45a79..061ec6d 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -1858,6 +1858,10 @@ 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; @@ -1866,26 +1870,30 @@ 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 stack_value_size_bits + = 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 > stack_value_size_bits) + 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 += stack_value_size_bits - p->size; + + copy_bitwise (contents, dest_offset_bits, + value_contents_all (p->v.value), + source_offset_bits, + this_size_bits, bits_big_endian); } break; @@ -1899,6 +1907,10 @@ 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; @@ -1915,12 +1927,6 @@ 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" " = "