From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by sourceware.org (Postfix) with ESMTPS id 2A1173857017 for ; Mon, 2 Oct 2023 12:50:48 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 2A1173857017 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 1281A1F7AB for ; Mon, 2 Oct 2023 12:50:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1696251047; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lR61ziUYxL7W1gjQX8Z4GWKXFRHxU1Ge7AdiaN1NX1c=; b=lUXOD+mVdPXgOWNkdtI3ROAlkHIAdKqVlHMghbi67YpbHJH/Z9FkFcqplwiBDgKU8XWJN4 9/3fxyvEKcYJHGkhwUkflkbHeKgLYkmpn3mszWKZ6vUII1KIr6Xj1KvwUsWrch1FYpvGaD qJlbHWzZ3FfHfHc5/lpQVpuMqG3wO1M= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1696251047; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lR61ziUYxL7W1gjQX8Z4GWKXFRHxU1Ge7AdiaN1NX1c=; b=zcJ9DHBNYpSSgTm4NduQT0giWfniktPF3iI0U2MXrInwZor0mFJLFV/bQfarASlBMXi/eB jRRe9Nd9yGxlPCBw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id F3B4F13434 for ; Mon, 2 Oct 2023 12:50:46 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id GMeLOqa8GmVZMgAAMHmgww (envelope-from ) for ; Mon, 02 Oct 2023 12:50:46 +0000 From: Tom de Vries To: gdb-patches@sourceware.org Subject: [PATCH 07/13] [gdb/symtab] Resolve deferred entries, inter-shard case Date: Mon, 2 Oct 2023 14:50:45 +0200 Message-Id: <20231002125051.29911-8-tdevries@suse.de> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20231002125051.29911-1-tdevries@suse.de> References: <20231002125051.29911-1-tdevries@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-11.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: With the test-case included in this patch, we run into: ... FAIL: gdb.dwarf2/forward-spec-inter-cu.exp: v has a parent ... due to v having the parent nullptr: ... [3] ((cooked_index_entry *) 0x7fc798005250)^M name: v^M canonical: v^M qualified: v^M DWARF tag: DW_TAG_variable^M flags: 0x2 [IS_STATIC]^M DIE offset: 0xbe^M parent: ((cooked_index_entry *) 0)^M ... while it should have the parent ns: ... [18] ((cooked_index_entry *) 0x7fc794002ed0)^M name: ns^M canonical: ns^M qualified: ns^M DWARF tag: DW_TAG_namespace^M flags: 0x0 []^M DIE offset: 0xde^M parent: ((cooked_index_entry *) 0)^M ... The corresponding dwarf is: ... Compilation Unit @ offset 0xb1: ... <0>: Abbrev Number: 2 (DW_TAG_compile_unit) DW_AT_language : 4 (C++) <1>: Abbrev Number: 3 (DW_TAG_variable) DW_AT_specification: <0xe2> DW_AT_location : (DW_OP_const1u: 23; DW_OP_stack_value) ... Compilation Unit @ offset 0xc8: ... <0>: Abbrev Number: 2 (DW_TAG_compile_unit) DW_AT_language : 4 (C++) ... <1>: Abbrev Number: 4 (DW_TAG_namespace) DW_AT_name : ns <2>: Abbrev Number: 5 (DW_TAG_variable) DW_AT_name : v DW_AT_type : <0xd5> DW_AT_declaration : 1 ... By switching on debug_handle_deferred_entries, we get: ... 0x00000000000000df 0x7f2b34007640 (0xde)^M 0x00000000000000ea 0x0^M ... So, the DIE 0xbe is not marked as deferred. And even if it would be, the incorrect value would be fetched, because m_die_range_map only has the scope of a parsing a single CU (with the exception of imported PUs, but only if the CU wins the race). [ Then there's the problem that find_parent cannot distinguish between the "no parent" and "don't know" cases, which means that getting the incorrect parent happens silently. ] We need to generically solve the case of inter-CU dependencies, and that includes inter-shard dependencies as well. On my system, the test-case exercises the inter-shard case, but that may be different on other systems, depending on number and size of CUs in the dwarf, and the number of worker threads. So we: - mark deferred entries in m_die_range_map using dummy cooked_index_entry parent_map::defered, to prevent incorrect entries for deferred dies, - defer all inter-CU dependencies (note that two subsequent patches implement optimizations to deal with this more optimally), - move m_die_range_map and m_deferred_dies to cooked_index_shard, and - move handle_deferred_dies to the cooked_index, where it is called in the constructor, and update it to handle the intra-shard case, such that we get: ... 0x00000000000000be 0x2934520 (deferred)^M 0x00000000000000bf 0x0^M 0x00000000000000df 0x7f4260002ee0 (0xde)^M 0x00000000000000ea 0x0^M Resolve deferred: 0xbe -> 0xe2: 0xde^M ... and consequently: ... [3] ((cooked_index_entry *) 0x7f4270002ee0)^M name: v^M canonical: v^M qualified: ns::v^M DWARF tag: DW_TAG_variable^M flags: 0x2 [IS_STATIC]^M DIE offset: 0xbe^M parent: ((cooked_index_entry *) 0x7f4260002ee0) [ns]^M ... Note that handling units from the .debug_info section alongside units from the .debug_types section requires us to extend form_addr to take is_debug_types into account. Tested on x86_64-linux. PR symtab/30846 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30846 --- gdb/dwarf2/cooked-index.c | 84 ++++++++++++++++++++++++++ gdb/dwarf2/cooked-index.h | 73 +++++++++++++++++++++- gdb/dwarf2/read.c | 124 ++++++++++++++++---------------------- 3 files changed, 207 insertions(+), 74 deletions(-) diff --git a/gdb/dwarf2/cooked-index.c b/gdb/dwarf2/cooked-index.c index 58ea541a5c9..68b5644cf23 100644 --- a/gdb/dwarf2/cooked-index.c +++ b/gdb/dwarf2/cooked-index.c @@ -228,6 +228,12 @@ cooked_index_entry::write_scope (struct obstack *storage, /* See cooked-index.h. */ +cooked_index_entry parent_map::deferred((sect_offset)0, (dwarf_tag)0, + (cooked_index_flag)0, nullptr, + nullptr, nullptr); + +/* See cooked-index.h. */ + const cooked_index_entry * cooked_index_shard::add (sect_offset die_offset, enum dwarf_tag tag, cooked_index_flag flags, const char *name, @@ -446,6 +452,8 @@ cooked_index_shard::wait (bool allow_quit) const cooked_index::cooked_index (vec_type &&vec) : m_vector (std::move (vec)) { + handle_deferred_entries (); + for (auto &idx : m_vector) idx->finalize (); @@ -649,6 +657,82 @@ cooked_index::maybe_write_index (dwarf2_per_bfd *per_bfd, global_index_cache.store (per_bfd, ctx); } +/* Set to true to debug handling of deferred entries. */ +const static bool debug_handle_deferred_entries = false; + +/* See cooked-index.h. */ + +const cooked_index_entry * +cooked_index_shard::resolve_deferred_entry + (const deferred_entry &de, const cooked_index_entry *parent_entry) +{ + if (debug_handle_deferred_entries) + { + gdb_printf (gdb_stdlog, + "Resolve deferred: 0x%" PRIx64 " -> 0x%lx: ", + to_underlying (de.die_offset), + de.spec_offset); + if (parent_entry == nullptr) + gdb_printf (gdb_stdlog, "no parent\n"); + else + gdb_printf (gdb_stdlog, "0x%" PRIx64 "\n", + to_underlying (parent_entry->die_offset)); + } + + return add (de.die_offset, de.tag, de.flags, de.name, + parent_entry, de.per_cu); +} + +/* See cooked-index.h. */ + +const cooked_index_entry * +cooked_index::find_parent_deferred_entry + (const cooked_index_shard::deferred_entry &entry) const +{ + const cooked_index_entry *parent_entry = nullptr; + for (auto &parent_map_shard : m_vector) + { + auto res = parent_map_shard->find_parent (entry.spec_offset); + if (res != nullptr) + { + /* We currently assume that no derrered entry is + dependent on another deferred entry. If that turns + out to be not the case, detect it here. */ + gdb_assert (res != &parent_map::deferred); + parent_entry = res; + break; + } + } + + return parent_entry; +} + +/* See cooked-index.h. */ + +void +cooked_index::handle_deferred_entries () +{ + if (debug_handle_deferred_entries) + for (auto &shard : m_vector) + shard->m_die_range_map->dump (); + + for (auto &shard : m_vector) + for (const auto &deferred_entry : *shard->m_deferred_entries) + { + const cooked_index_entry *parent_entry + = find_parent_deferred_entry (deferred_entry); + shard->resolve_deferred_entry (deferred_entry, parent_entry); + } + + for (auto &shard : m_vector) + { + delete shard->m_die_range_map; + shard->m_die_range_map = nullptr; + delete shard->m_deferred_entries; + shard->m_deferred_entries = nullptr; + } +} + /* Wait for all the index cache entries to be written before gdb exits. */ static void diff --git a/gdb/dwarf2/cooked-index.h b/gdb/dwarf2/cooked-index.h index 396c25b0718..3a582d187c2 100644 --- a/gdb/dwarf2/cooked-index.h +++ b/gdb/dwarf2/cooked-index.h @@ -242,6 +242,10 @@ struct cooked_index_entry : public allocate_on_obstack class parent_map { public: + /* A dummy cooked_index_entry to mark that computing the parent has been + deferred. */ + static cooked_index_entry deferred; + /* Find the parent of DIE LOOKUP. */ const cooked_index_entry *find_parent (CORE_ADDR lookup) const { @@ -276,6 +280,13 @@ class parent_map = (const cooked_index_entry *)value; if (parent_entry == nullptr) return; + + if (parent_entry == &parent_map::deferred) + { + gdb_printf (outfile, " (deferred)"); + return; + } + gdb_printf (outfile, " (0x%" PRIx64 ")", to_underlying (parent_entry->die_offset)); }; @@ -301,7 +312,11 @@ class cooked_index; class cooked_index_shard { public: - cooked_index_shard () = default; + cooked_index_shard () { + m_die_range_map = new parent_map; + m_deferred_entries = new std::vector; + } + DISABLE_COPY_AND_ASSIGN (cooked_index_shard); /* Create a new cooked_index_entry and register it with this object. @@ -345,6 +360,41 @@ class cooked_index_shard for completion, will be returned. */ range find (const std::string &name, bool completing) const; + /* Find the parent of DIE LOOKUP. */ + const cooked_index_entry * + find_parent (CORE_ADDR lookup) const + { + return m_die_range_map->find_parent (lookup); + } + + /* Set the parent of DIES in range [START, END] to PARENT_ENTRY. */ + void set_parent (CORE_ADDR start, CORE_ADDR end, + const cooked_index_entry *parent_entry) + { + m_die_range_map->set_parent (start, end, parent_entry); + } + + /* A single deferred entry. See m_deferred_entries. */ + struct deferred_entry + { + sect_offset die_offset; + const char *name; + CORE_ADDR spec_offset; + dwarf_tag tag; + cooked_index_flag flags; + dwarf2_per_cu_data *per_cu; + }; + + /* Defer creating a cooked_index_entry corresponding to DEFERRED. */ + void defer_entry (deferred_entry de) + { + m_deferred_entries->push_back (de); + } + + /* Variant of add that takes a deferred_entry as parameter. */ + const cooked_index_entry *resolve_deferred_entry + (const deferred_entry &entry, const cooked_index_entry *parent_entry); + private: /* Return the entry that is believed to represent the program's @@ -402,6 +452,20 @@ class cooked_index_shard that the 'get' method is never called on this future, only 'wait'. */ gdb::future m_future; + + /* An addrmap that maps from section offsets (see the form_addr + method) to newly-created entries. See m_deferred_entries to + understand this. */ + parent_map *m_die_range_map; + + /* The generated DWARF can sometimes have the declaration for a + method in a class (or perhaps namespace) scope, with the + definition appearing outside this scope... just one of the many + bad things about DWARF. In order to handle this situation, we + defer certain entries until the end of scanning, at which point + we'll know the containing context of all the DIEs that we might + have scanned. This vector stores these deferred entries. */ + std::vector *m_deferred_entries; }; /* The main index of DIEs. The parallel DIE indexers create @@ -485,6 +549,13 @@ class cooked_index : public dwarf_scanner_base private: + /* Find the parent corresponding to deferred entry ENTRY. */ + const cooked_index_entry *find_parent_deferred_entry + (const cooked_index_shard::deferred_entry &entry) const; + + /* Create cooked_index_entries for the deferred entries. */ + void handle_deferred_entries (); + /* Maybe write the index to the index cache. */ void maybe_write_index (dwarf2_per_bfd *per_bfd, const index_cache_store_context &); diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index 23de6714268..87955d1d2e1 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -4670,6 +4670,25 @@ class cooked_index_storage return &m_addrmap; } + /* Find the parent of DIE LOOKUP. */ + const cooked_index_entry *find_parent (CORE_ADDR lookup) + { + return m_index->find_parent (lookup); + } + + /* Set the parent of DIES in range [START, END] to PARENT_ENTRY. */ + void set_parent (CORE_ADDR start, CORE_ADDR end, + const cooked_index_entry *parent_entry) + { + m_index->set_parent (start, end, parent_entry); + } + + /* Defer creating a cooked_index_entry corresponding to deferred_entry DE. */ + void defer_entry (cooked_index_shard::deferred_entry de) + { + m_index->defer_entry (de); + } + private: /* Hash function for a cutu_reader. */ @@ -4722,11 +4741,13 @@ class cooked_indexer /* A helper function to turn a section offset into an address that can be used in an addrmap. */ - CORE_ADDR form_addr (sect_offset offset, bool is_dwz) + CORE_ADDR form_addr (sect_offset offset, bool is_dwz, bool is_debug_types) { CORE_ADDR value = to_underlying (offset); if (is_dwz) value |= ((CORE_ADDR) 1) << (8 * sizeof (CORE_ADDR) - 1); + if (is_debug_types) + value |= ((CORE_ADDR) 1) << (8 * sizeof (CORE_ADDR) - 2); return value; } @@ -4802,77 +4823,20 @@ class cooked_indexer /* Find the parent of DIE LOOKUP. */ const cooked_index_entry *find_parent (CORE_ADDR lookup) const { - return m_die_range_map.find_parent (lookup); + return m_index_storage->find_parent (lookup); } /* Set the parent of DIES in range [START, END] to PARENT_ENTRY. */ void set_parent (CORE_ADDR start, CORE_ADDR end, const cooked_index_entry *parent_entry) { - m_die_range_map.set_parent (start, end, parent_entry); + m_index_storage->set_parent (start, end, parent_entry); } - /* A single deferred entry. */ - struct deferred_entry - { - sect_offset die_offset; - const char *name; - CORE_ADDR spec_offset; - dwarf_tag tag; - cooked_index_flag flags; - }; - - /* The generated DWARF can sometimes have the declaration for a - method in a class (or perhaps namespace) scope, with the - definition appearing outside this scope... just one of the many - bad things about DWARF. In order to handle this situation, we - defer certain entries until the end of scanning, at which point - we'll know the containing context of all the DIEs that we might - have scanned. This vector stores these deferred entries. */ - std::vector m_deferred_entries; - /* Defer creating a cooked_index_entry corresponding to deferred_entry DE. */ - void defer_entry (const deferred_entry &de) + void defer_entry (const cooked_index_shard::deferred_entry &de) { - m_deferred_entries.push_back (de); - } - - /* Set to true to debug handling of deferred entries. */ - const bool debug_handle_deferred_entries = false; - - /* Create a cooked_index_entry corresponding to deferred_entry DE with - parent PARENT_ENTRY. */ - const cooked_index_entry *resolve_deferred_entry - (const deferred_entry &de, const cooked_index_entry *parent_entry) - { - if (debug_handle_deferred_entries) - { - gdb_printf (gdb_stdlog, - "Resolve deferred: 0x%" PRIx64 " -> 0x%lx: ", - to_underlying (de.die_offset), - de.spec_offset); - if (parent_entry == nullptr) - gdb_printf (gdb_stdlog, "no parent\n"); - else - gdb_printf (gdb_stdlog, "0x%" PRIx64 "\n", - to_underlying (parent_entry->die_offset)); - } - return m_index_storage->add (de.die_offset, de.tag, de.flags, de.name, - parent_entry, m_per_cu); - } - - /* Create cooked_index_entries for the deferred entries. */ - void handle_deferred_entries () - { - if (debug_handle_deferred_entries) - m_die_range_map.dump (); - - for (const auto &entry : m_deferred_entries) - { - const cooked_index_entry *parent_entry - = find_parent (entry.spec_offset); - resolve_deferred_entry (entry, parent_entry); - } + m_index_storage->defer_entry (de); } }; @@ -16406,13 +16370,22 @@ cooked_indexer::scan_attributes (dwarf2_per_cu_data *scanning_per_cu, const gdb_byte *new_info_ptr = (new_reader->buffer + to_underlying (origin_offset)); - if (new_reader->cu == reader->cu - && new_info_ptr > watermark_ptr + if ((new_reader->cu != reader->cu + || (new_reader->cu == reader->cu + && new_info_ptr > watermark_ptr)) && *parent_entry == nullptr) - *maybe_defer = form_addr (origin_offset, origin_is_dwz); + { + gdb_assert (reader->cu->per_cu->is_debug_types + == new_reader->cu->per_cu->is_debug_types); + *maybe_defer = form_addr (origin_offset, origin_is_dwz, + reader->cu->per_cu->is_debug_types); + } else if (*parent_entry == nullptr) { - CORE_ADDR lookup = form_addr (origin_offset, origin_is_dwz); + gdb_assert (reader->cu->per_cu->is_debug_types + == new_reader->cu->per_cu->is_debug_types); + CORE_ADDR lookup = form_addr (origin_offset, origin_is_dwz, + reader->cu->per_cu->is_debug_types); *parent_entry = find_parent (lookup); } @@ -16532,9 +16505,11 @@ cooked_indexer::recurse (cutu_reader *reader, /* Both start and end are inclusive, so use both "+ 1" and "- 1" to limit the range to the children of parent_entry. */ CORE_ADDR start = form_addr (parent_entry->die_offset + 1, - reader->cu->per_cu->is_dwz); + reader->cu->per_cu->is_dwz, + reader->cu->per_cu->is_debug_types); CORE_ADDR end = form_addr (sect_offset (info_ptr - 1 - reader->buffer), - reader->cu->per_cu->is_dwz); + reader->cu->per_cu->is_dwz, + reader->cu->per_cu->is_debug_types); set_parent (start, end, parent_entry); } @@ -16601,9 +16576,14 @@ cooked_indexer::index_dies (cutu_reader *reader, if (name != nullptr) { if (defer != 0) - defer_entry ({ - this_die, name, defer, abbrev->tag, flags - }); + { + CORE_ADDR addr = form_addr (this_die, reader->cu->per_cu->is_dwz, + reader->cu->per_cu->is_debug_types); + set_parent (addr, addr, &parent_map::deferred); + defer_entry ({ + this_die, name, defer, abbrev->tag, flags, m_per_cu + }); + } else this_entry = m_index_storage->add (this_die, abbrev->tag, flags, name, this_parent_entry, @@ -16705,8 +16685,6 @@ cooked_indexer::make_index (cutu_reader *reader) if (!reader->comp_unit_die->has_children) return; index_dies (reader, reader->info_ptr, nullptr, false); - - handle_deferred_entries (); } /* An implementation of quick_symbol_functions for the cooked DWARF -- 2.35.3