From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id aQQfHT1k1F8HAgAAWB0awg (envelope-from ) for ; Sat, 12 Dec 2020 01:33:33 -0500 Received: by simark.ca (Postfix, from userid 112) id 6C4BC1F0AA; Sat, 12 Dec 2020 01:33:33 -0500 (EST) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 7D00D1EF4B for ; Sat, 12 Dec 2020 01:33:32 -0500 (EST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id AC0C2384B00F; Sat, 12 Dec 2020 06:33:31 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org AC0C2384B00F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1607754811; bh=fWqqVS8cOCVpL5DjI+4Ci+9Nz5EDgLzmFM/dLM8FL1o=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=Pf7an/O9pkT6QmzzYKdoaFME5cWzQyLDJxt3PHWIZx6ETRoTaOMq/E8HlrO7sWhie N74QK5g/B5sX+K/gDbT5Hj40CdZHWlg/trWSK4mEti17hKzQYjeYuKjRjpS9meuHb4 lonEoW/bjvsdeWDNT020Xs91u1SfLcPIhLLtm1Ys= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id A8A723857827 for ; Sat, 12 Dec 2020 06:33:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org A8A723857827 Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 0BC6XMss028556 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 12 Dec 2020 01:33:27 -0500 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 0BC6XMss028556 Received: from [10.0.0.11] (173-246-6-90.qc.cable.ebox.net [173.246.6.90]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id 1E8081EF4B; Sat, 12 Dec 2020 01:33:22 -0500 (EST) Subject: Re: [PUSHED] gdb/fortran: Support negative array stride in one limited case To: Andrew Burgess , gdb-patches@sourceware.org References: <87eev9kn0u.fsf@redhat.com> <20200225163500.13749-1-andrew.burgess@embecosm.com> Message-ID: <62551675-7b8d-a6af-113e-d59ad6c2334f@polymtl.ca> Date: Sat, 12 Dec 2020 01:33:21 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 MIME-Version: 1.0 In-Reply-To: <20200225163500.13749-1-andrew.burgess@embecosm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Sat, 12 Dec 2020 06:33:22 +0000 X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Simon Marchi via Gdb-patches Reply-To: Simon Marchi Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" Hi Andrew, Sorry to revive this thread. I build my GDB with ASan, and I see the gdb.fortran/vla-type.exp test crashing GDB with: ptype fivedynarr(2) /home/smarchi/src/binutils-gdb/gdb/valarith.c:1171:10: runtime error: signed integer overflow: 16777216 * 140737351048816 cannot be represented in type 'long int' Commit 5bbd8269fa8d ("gdb/fortran: array stride support") is the first one where it does this. Simon On 2020-02-25 11:35 a.m., Andrew Burgess wrote: > I've pushed this fix now. The exact patch I pushed is included below. > > > Thanks, > Andrew > > > > > --- > > This commit adds support for negative Fortran array strides in one > limited case, that is the case of a single element array with a > negative array stride. > > The changes in this commit will be required in order for more general > negative array stride support to work correctly, however, right now > other problems in GDB prevent negative array strides from working in > the general case. > > The reason negative array strides don't currently work in the general > case is that when dealing with such arrays, the base address for the > objects data is actually the highest addressed element, subsequent > elements are then accessed with a negative offset from that address, > and GDB is not currently happy with this configuration. > > The changes here can be summarised as, stop treating signed values as > unsigned, specifically, the array stride, and offsets calculated using > the array stride. > > This issue was identified on the mailing list by Sergio: > > https://sourceware.org/ml/gdb-patches/2020-01/msg00360.html > > The test for this issue is a new one written by me as the copyright > status of the original test is currently unknown. > > gdb/ChangeLog: > > * gdbtypes.c (create_array_type_with_stride): Handle negative > array strides. > * valarith.c (value_subscripted_rvalue): Likewise. > > gdb/testsuite/ChangeLog: > > * gdb.fortran/derived-type-striding.exp: Add a new test. > * gdb.fortran/derived-type-striding.f90: Add pointer variable for > new test. > --- > gdb/ChangeLog | 6 ++++++ > gdb/gdbtypes.c | 17 +++++++++++++---- > gdb/testsuite/ChangeLog | 6 ++++++ > gdb/testsuite/gdb.fortran/derived-type-striding.exp | 2 ++ > gdb/testsuite/gdb.fortran/derived-type-striding.f90 | 2 ++ > gdb/valarith.c | 4 ++-- > 6 files changed, 31 insertions(+), 6 deletions(-) > > diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c > index 85758930491..ef110b30445 100644 > --- a/gdb/gdbtypes.c > +++ b/gdb/gdbtypes.c > @@ -1223,7 +1223,7 @@ create_array_type_with_stride (struct type *result_type, > && !type_not_allocated (result_type))) > { > LONGEST low_bound, high_bound; > - unsigned int stride; > + int stride; > > /* If the array itself doesn't provide a stride value then take > whatever stride the range provides. Don't update BIT_STRIDE as > @@ -1241,9 +1241,18 @@ create_array_type_with_stride (struct type *result_type, > In such cases, the array length should be zero. */ > if (high_bound < low_bound) > TYPE_LENGTH (result_type) = 0; > - else if (stride > 0) > - TYPE_LENGTH (result_type) = > - (stride * (high_bound - low_bound + 1) + 7) / 8; > + else if (stride != 0) > + { > + /* Ensure that the type length is always positive, even in the > + case where (for example in Fortran) we have a negative > + stride. It is possible to have a single element array with a > + negative stride in Fortran (this doesn't mean anything > + special, it's still just a single element array) so do > + consider that case when touching this code. */ > + LONGEST element_count = abs (high_bound - low_bound + 1); > + TYPE_LENGTH (result_type) > + = ((abs (stride) * element_count) + 7) / 8; > + } > else > TYPE_LENGTH (result_type) = > TYPE_LENGTH (element_type) * (high_bound - low_bound + 1); > diff --git a/gdb/testsuite/gdb.fortran/derived-type-striding.exp b/gdb/testsuite/gdb.fortran/derived-type-striding.exp > index 094843ca8b1..639dc4c9528 100644 > --- a/gdb/testsuite/gdb.fortran/derived-type-striding.exp > +++ b/gdb/testsuite/gdb.fortran/derived-type-striding.exp > @@ -41,3 +41,5 @@ gdb_test "p point_dimension" "= \\\(2, 2, 2, 2, 2, 2, 2, 2, 2\\\)" > # Test mixed type derived type. > if { $gcc_with_broken_stride } { setup_kfail *-*-* gcc/92775 } > gdb_test "p point_mixed_dimension" "= \\\(3, 3, 3, 3\\\)" > + > +gdb_test "p cloud_slice" " = \\\(\\\( x = 1, y = 2, z = 3 \\\)\\\)" > diff --git a/gdb/testsuite/gdb.fortran/derived-type-striding.f90 b/gdb/testsuite/gdb.fortran/derived-type-striding.f90 > index 26829f51dc0..fb537579faa 100644 > --- a/gdb/testsuite/gdb.fortran/derived-type-striding.f90 > +++ b/gdb/testsuite/gdb.fortran/derived-type-striding.f90 > @@ -28,9 +28,11 @@ program derived_type_member_stride > type(mixed_cartesian), dimension(10), target :: mixed_cloud > integer(kind=8), dimension(:), pointer :: point_dimension => null() > integer(kind=8), dimension(:), pointer :: point_mixed_dimension => null() > + type(cartesian), dimension(:), pointer :: cloud_slice => null() > cloud(:)%x = 1 > cloud(:)%y = 2 > cloud(:)%z = 3 > + cloud_slice => cloud(3:2:-2) > point_dimension => cloud(1:9)%y > mixed_cloud(:)%x = 1 > mixed_cloud(:)%y = 2 > diff --git a/gdb/valarith.c b/gdb/valarith.c > index 79b148602bb..be0e0731bee 100644 > --- a/gdb/valarith.c > +++ b/gdb/valarith.c > @@ -187,7 +187,7 @@ value_subscripted_rvalue (struct value *array, LONGEST index, LONGEST lowerbound > { > struct type *array_type = check_typedef (value_type (array)); > struct type *elt_type = check_typedef (TYPE_TARGET_TYPE (array_type)); > - ULONGEST elt_size = type_length_units (elt_type); > + LONGEST elt_size = type_length_units (elt_type); > > /* Fetch the bit stride and convert it to a byte stride, assuming 8 bits > in a byte. */ > @@ -199,7 +199,7 @@ value_subscripted_rvalue (struct value *array, LONGEST index, LONGEST lowerbound > elt_size = stride / (unit_size * 8); > } > > - ULONGEST elt_offs = elt_size * (index - lowerbound); > + LONGEST elt_offs = elt_size * (index - lowerbound); > > if (index < lowerbound > || (!TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (array_type) >