From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id OftgNNDjdWpp8RAAWB0awg (envelope-from ) for ; Fri, 07 Aug 2026 09:55:28 -0400 Received: by simark.ca (Postfix, from userid 112) id D25D51E167; Fri, 07 Aug 2026 09:55:28 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-25) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-5.3 required=5.0 tests=ARC_SIGNED,ARC_VALID,BAYES_00, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham autolearn_force=no version=4.0.1 Received: from vm01.sourceware.org (vm01.sourceware.org [38.145.34.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 073F71E09B for ; Fri, 07 Aug 2026 09:55:28 -0400 (EDT) Received: from vm01.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 21B164BB5883 for ; Fri, 7 Aug 2026 13:55:27 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 21B164BB5883 Received: from simark.ca (simark.ca [158.69.221.121]) by sourceware.org (Postfix) with ESMTPS id 9CEBD4BA9021 for ; Fri, 7 Aug 2026 13:55:03 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9CEBD4BA9021 Authentication-Results: sourceware.org; dmarc=fail (p=none dis=none) header.from=efficios.com Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=efficios.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 9CEBD4BA9021 Authentication-Results: sourceware.org; arc=none smtp.remote-ip=158.69.221.121 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1786110903; cv=none; b=orfYV5tczNy6ruE01Sjtgp5EMFAVxh/PlohgLycvc2xF9tZv6U63VYzm8EIrnJnuuUMdVnxTS/Bd7ne/xnYhqR9K7DVICfGQT6iSAnQo07jjC28ifu4PrufJEmt14MGa8KIKeYoRPCr9LSREBk+Oedj1HGYHsnwih22Y3g46RsA= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1786110903; c=relaxed/simple; bh=WVId7aG4ojqcNjzE5PvpvX2X2A6X/UZHs+KJ17ioFGA=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=q6IyKKBLdSzpgMsSGbZ8GvF8qdBbues/zTiChDertCgS/kqrCW8LYb42HPbLbY83d+0zPYSdkG1zJwIx08W3knXbDZ7xWfyJs0591USyIVBPWiVaQI2W7QF8qMPOlCpPLvkL1PhbN93vgLh/AWfs7ELqQVzwV/a8PaYzWtXQxwQ= ARC-Authentication-Results: i=1; sourceware.org DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9CEBD4BA9021 Received: by simark.ca (Postfix) id DA7791E09B; Fri, 07 Aug 2026 09:55:02 -0400 (EDT) From: Simon Marchi To: gdb-patches@sourceware.org Cc: Simon Marchi Subject: [PATCH v4 08/10] gdb: add objfile -> solib backlink Date: Fri, 7 Aug 2026 09:52:26 -0400 Message-ID: <20260807135259.111194-9-simon.marchi@efficios.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807135259.111194-1-simon.marchi@efficios.com> References: <20260807135259.111194-1-simon.marchi@efficios.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces~public-inbox=simark.ca@sourceware.org From: Simon Marchi The following "multiple solib_ops" patch will require accessing the solib(s) related to an objfile fairly often. To make that easier, add an objfile to solib backlink. However, I learned that there may be more than one solib linked to one objfile. The only case I am aware of is the dynamic linker itself (ld-linux.so), where the same instance (same load address) appears in all namespaces. We get one solib per "view" of that library, but they all point to the same objfile. So this backlink is actually a vector. Rename find_solib_for_objfile to find_one_solib_for_objfile to reflect that this function returns just one of possible multiple solibs for the given objfile (if that ever matters). To be clear, this doesn't change its behavior, this is what it was doing before this patch. Change-Id: I427d19407fdbc274b1790e0cae3004ee5fdbea72 --- gdb/objfiles.h | 25 +++++++++++++++++++++++++ gdb/solib-svr4.c | 16 ++++++---------- gdb/solib.c | 13 +++++++++---- 3 files changed, 40 insertions(+), 14 deletions(-) diff --git a/gdb/objfiles.h b/gdb/objfiles.h index 406ab36b39d6..fa265f83b792 100644 --- a/gdb/objfiles.h +++ b/gdb/objfiles.h @@ -450,6 +450,27 @@ struct objfile : intrusive_list_node /* Return the program space associated with this objfile. */ program_space *pspace () { return m_pspace; } + /* Return the first solib associated to this objfile, or nullptr if there are + none. */ + solib *first_solib () + { return !m_solibs.empty () ? m_solibs[0] : nullptr; } + + /* Add SOLIB to the list of solibs associated to this objfile. */ + void add_solib (solib &solib) + { + gdb_assert (std::find (m_solibs.begin (), m_solibs.end (), &solib) + == m_solibs.end ()); + m_solibs.emplace_back (&solib); + } + + /* Remove SOLIB from the list of solibs associated to this objfile. */ + void remove_solib (solib &solib) + { + auto it = std::find (m_solibs.begin (), m_solibs.end (), &solib); + gdb_assert (it != m_solibs.end ()); + m_solibs.erase (it); + } + using compunit_symtab_iterator = owning_intrusive_list::iterator; using compunit_symtab_range = iterator_range; @@ -702,6 +723,10 @@ struct objfile : intrusive_list_node program_space *m_pspace; + /* The solibs associated to this objfile. This is a 1 objfile to N solibs + relationship (see solib.c for details). */ + std::vector m_solibs; + public: /* The object file's BFD. Can be null if the objfile contains only minimal symbols (e.g. the run time common symbols for SunOS4) or diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index 35c81000b10a..8b61517c326f 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -3592,10 +3592,10 @@ lp64_svr4_solib_ops::fetch_link_map_offsets () const } -/* Return the DSO matching OBJFILE or nullptr if none can be found. */ +/* Return one solib matching OBJFILE or nullptr if none can be found. */ -static const solib * -find_solib_for_objfile (struct objfile *objfile) +static solib * +find_one_solib_for_objfile (struct objfile *objfile) { if (objfile == nullptr) return nullptr; @@ -3605,11 +3605,7 @@ find_solib_for_objfile (struct objfile *objfile) if (objfile->separate_debug_objfile_backlink != nullptr) objfile = objfile->separate_debug_objfile_backlink; - for (const solib &so : current_program_space->solibs ()) - if (so.objfile == objfile) - return &so; - - return nullptr; + return objfile->first_solib (); } /* Return the address of the r_debug object for the namespace containing @@ -3676,7 +3672,7 @@ svr4_solib_ops::iterate_over_objfiles_in_search_order r_debug object, defaulting to the initial namespace. */ svr4_info *info = get_svr4_info (current_program_space); CORE_ADDR default_debug_base = this->default_debug_base (info); - const solib *curr_solib = find_solib_for_objfile (current_objfile); + const solib *curr_solib = find_one_solib_for_objfile (current_objfile); CORE_ADDR debug_base = find_debug_base_for_solib (curr_solib); if (debug_base == 0) debug_base = default_debug_base; @@ -3691,7 +3687,7 @@ svr4_solib_ops::iterate_over_objfiles_in_search_order If we fail, e.g. for manually added symbol files or for the main executable, we assume that they were added to the initial namespace. */ - const solib *solib = find_solib_for_objfile (&objfile); + const solib *solib = find_one_solib_for_objfile (&objfile); CORE_ADDR solib_base = find_debug_base_for_solib (solib); if (solib_base == 0) solib_base = default_debug_base; diff --git a/gdb/solib.c b/gdb/solib.c index 6afa97e1aed5..b9b0f11cb477 100644 --- a/gdb/solib.c +++ b/gdb/solib.c @@ -650,6 +650,7 @@ solib_read_symbols (solib &so, symfile_add_flags flags) so.objfile->addr_low = so.addr_low; } + so.objfile->add_solib (so); so.symbols_loaded = true; } catch (const gdb_exception_error &e) @@ -715,10 +716,14 @@ remove_solib (program_space *pspace, notify_solib_unloaded (pspace, *solib_it, still_in_use, false); /* Unless the user loaded it explicitly, free SO's objfile. */ - if (solib_it->objfile != nullptr - && !(solib_it->objfile->flags & OBJF_USERLOADED) - && !still_in_use) - solib_it->objfile->unlink (); + if (solib_it->objfile != nullptr) + { + /* Remove the objfile -> solib backlink. */ + solib_it->objfile->remove_solib (*solib_it); + + if (!(solib_it->objfile->flags & OBJF_USERLOADED) && !still_in_use) + solib_it->objfile->unlink (); + } pspace->deleted_solibs.push_back (solib_it->name); -- 2.55.0