From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 436C43857831; Fri, 6 Aug 2021 16:02:33 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 436C43857831 From: "cvs-commit at gcc dot gnu.org" To: gdb-prs@sourceware.org Subject: [Bug gdb/28004] DW_AT_ranges with form DW_FORM_sec_offset problem Date: Fri, 06 Aug 2021 16:02:33 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gdb X-Bugzilla-Component: gdb X-Bugzilla-Version: HEAD X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: cvs-commit at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: 11.1 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gdb-prs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-prs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Aug 2021 16:02:33 -0000 https://sourceware.org/bugzilla/show_bug.cgi?id=3D28004 --- Comment #13 from cvs-commit at gcc dot gnu.org --- The gdb-11-branch branch has been updated by Tom de Vries : https://sourceware.org/git/gitweb.cgi?p=3Dbinutils-gdb.git;h=3Da656ee0831be= a07e57876aa933ce4fe2063c2355 commit a656ee0831bea07e57876aa933ce4fe2063c2355 Author: Tom de Vries Date: Fri Aug 6 18:02:28 2021 +0200 [gdb/symtab] Fix zero address complaint for shlib In PR28004 the following warning / Internal error is reported: ... $ gdb -q -batch \ -iex "set sysroot $(pwd -P)/repro" \ ./repro/gdb \ ./repro/core \ -ex bt ... Program terminated with signal SIGABRT, Aborted. #0 0x00007ff8fe8e5d22 in raise () from repro/usr/lib/libc.so.6 [Current thread is 1 (LWP 1762498)] #1 0x00007ff8fe8cf862 in abort () from repro/usr/lib/libc.so.6 warning: (Internal error: pc 0x7ff8feb2c21d in read in psymtab, \ but not in symtab.) warning: (Internal error: pc 0x7ff8feb2c218 in read in psymtab, \ but not in symtab.) ... #2 0x00007ff8feb2c21e in __gnu_debug::_Error_formatter::_M_error() co= nst \ [clone .cold] (warning: (Internal error: pc 0x7ff8feb2c21d in read i= n \ psymtab, but not in symtab.) ) from repro/usr/lib/libstdc++.so.6 ... The warning is about the following: - in find_pc_sect_compunit_symtab we try to find the address (0x7ff8feb2c218 / 0x7ff8feb2c21d) in the symtabs. - that fails, so we try again in the partial symtabs. - we find a matching partial symtab - however, the partial symtab has a full symtab, so we should have found a matching symtab in the first step. The addresses are: ... (gdb) info sym 0x7ff8feb2c218 __gnu_debug::_Error_formatter::_M_error() const [clone .cold] in \ section .text of repro/usr/lib/libstdc++.so.6 (gdb) info sym 0x7ff8feb2c21d __gnu_debug::_Error_formatter::_M_error() const [clone .cold] + 5 in \ section .text of repro/usr/lib/libstdc++.so.6 ... which correspond to unrelocated addresses 0x9c218 and 0x9c21d: ... $ nm -C repro/usr/lib/libstdc++.so.6.0.29 | grep 000000000009c218 000000000009c218 t __gnu_debug::_Error_formatter::_M_error() const \ [clone .cold] ... which belong to function __gnu_debug::_Error_formatter::_M_error() in /build/gcc/src/gcc/libstdc++-v3/src/c++11/debug.cc. The partial symtab that is found for the addresses is instead the one f= or /build/gcc/src/gcc/libstdc++-v3/src/c++98/bitmap_allocator.cc, which is incorrect. This happens as follows. The bitmap_allocator.cc CU has DW_AT_ranges at .debug_rnglist offset 0x4b50: ... 00004b50 0000000000000000 0000000000000056 00004b5a 00000000000a4790 00000000000a479c 00004b64 00000000000a47a0 00000000000a47ac ... When reading the first range 0x0..0x56, it doesn't trigger the "start address of zero" complaint here: ... /* A not-uncommon case of bad debug info. Don't pollute the addrmap with bad data. */ if (range_beginning + baseaddr =3D=3D 0 && !per_objfile->per_bfd->has_section_at_zero) { complaint (_(".debug_rnglists entry has start address of zero" " [in module %s]"), objfile_name (objfile)); continue; } ... because baseaddr !=3D 0, which seems incorrect given that when loading = the shared library individually in gdb (and consequently baseaddr =3D=3D 0)= , we do see the complaint. Consequently, we run into this case in dwarf2_get_pc_bounds: ... if (low =3D=3D 0 && !per_objfile->per_bfd->has_section_at_zero) return PC_BOUNDS_INVALID; ... which then results in this code in process_psymtab_comp_unit_reader bei= ng called with cu_bounds_kind =3D=3D PC_BOUNDS_INVALID, which sets the set= _addrmap argument to 1: ... scan_partial_symbols (first_die, &lowpc, &highpc, cu_bounds_kind <=3D PC_BOUNDS_INVALID, cu); ... and consequently, the CU addrmap gets build using address info from the functions. During that process, addrmap_set_empty is called with a range that incl= udes 0x9c218 and 0x9c21d: ... (gdb) p /x start $7 =3D 0x9989c (gdb) p /x end_inclusive $8 =3D 0xb200d ... but it's called for a function at DIE 0x54153 with DW_AT_ranges at 0x40= ae: ... 000040ae 00000000000b1ee0 00000000000b200e 000040b9 000000000009989c 00000000000998c4 000040c3 ... and neither range includes 0x9c218 and 0x9c21d. This is caused by this code in partial_die_info::read: ... if (dwarf2_ranges_read (ranges_offset, &lowpc, &highpc, cu, nullptr, tag)) has_pc_info =3D 1; ... which pretends that the function is located at addresses 0x9989c..0xb20= 0d, which is indeed not the case. This patch fixes the first problem encountered: fix the "start address = of zero" complaint warning by removing the baseaddr part from the conditio= n. Same for dwarf2_ranges_process. The effect is that: - the complaint is triggered, and - the warning / Internal error is no longer triggered. This does not fix the observed problem in partial_die_info::read, which= is filed as PR28200. Tested on x86_64-linux. Co-Authored-By: Simon Marchi gdb/ChangeLog: 2021-08-06 Simon Marchi Tom de Vries PR symtab/28004 * dwarf2/read.c (dwarf2_rnglists_process, dwarf2_ranges_process= ): Fix zero address complaint. gdb/testsuite/ChangeLog: 2021-08-06 Simon Marchi Tom de Vries PR symtab/28004 * gdb.dwarf2/dw2-zero-range-shlib.c: New test. * gdb.dwarf2/dw2-zero-range.c: New test. * gdb.dwarf2/dw2-zero-range.exp: New file. --=20 You are receiving this mail because: You are on the CC list for the bug.=