From patchwork Fri Jul 3 16:46:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Matthias_M=C3=A4nnich?= X-Patchwork-Id: 39883 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 194883844079; Fri, 3 Jul 2020 16:47:39 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 194883844079 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1593794859; bh=3xNiIhvY8a2SuyeXoHKYtTVvFs8RkQB8jbqFoOy8p20=; h=Date:In-Reply-To:References:Subject:To:List-Id:List-Unsubscribe: List-Archive:List-Help:List-Subscribe:From:Reply-To:Cc:From; b=aJ0HGijcBLVh3H5nrXhTmgCQh9QsDGMxK/HTNyOD1QyKTNEsKcofhGkl5Jqdb6Aqd /OAm2vtysLvLqhrlZbIS07cT6RrrDD4bTf+vIHEfpW5E2lLtfaLQR0oI47Zh5i0kMc GirF9lsMsbVgWlW4M15wGqJyVxg3BjGeb1iq+auI= X-Original-To: libabigail@sourceware.org Delivered-To: libabigail@sourceware.org Received: from mail-wr1-x449.google.com (mail-wr1-x449.google.com [IPv6:2a00:1450:4864:20::449]) by sourceware.org (Postfix) with ESMTPS id 1C5003844079 for ; Fri, 3 Jul 2020 16:47:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1C5003844079 Received: by mail-wr1-x449.google.com with SMTP id b14so32325983wrp.0 for ; Fri, 03 Jul 2020 09:47:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=3xNiIhvY8a2SuyeXoHKYtTVvFs8RkQB8jbqFoOy8p20=; b=ZQEqFNR919xiBIEJF/S7typxTgN+ecQjMH8e26BwagwHceGPJ0WBvXpIjK//LwoT3J FwriTPXrDVIu4b3L1Kc1D1G3R1BZKj0Q+iIrngogvFdjVILD16KXYI/4fWjU6ZxTnJ5n 6bMTgdKWv6BhmvJKjAyA8PtucPNrDHeQqMoM7VNMGKxJXj5EFVT1J2Cu5LFy5EvCcdMl A8PlhAvEDW6twHC5uvrPI7zK8EpQ+oWI5d+tZTRtK+UFMZ1Iyjc7RO2xnxFc22lP3ipG XpyFN6f0sSBnrwWaoZh+K2riRvuOcFoBioxpEZVcYW9TYdPz+8XeIj2fO/xEZEamNYs6 ECHA== X-Gm-Message-State: AOAM5300fP/tbJy5jqBq9fIdCiJQNuUS0FJEjzeOq7tv8YKzxvKV6Vr9 F8etH/S1Cb1AvuCgQF8d1GmS4PTWMxmgg2LHoNI1NRmQrut9H7KWDegerUYemy4lkVgBVPcm3DI 0W6y35OIeFXHfXRkJe8VYBPr68SHU5pRZCz1rSqCAGN0IfBN54d9sPZLJfp8OYnVaSnjzSi0= X-Google-Smtp-Source: ABdhPJyIX5XsmR+67AGpp7+aTuEhUMnkXudsrzZ8QNcLcvcfmcK/VoWe6QDwdVEin1VRFK2pmI69I1qzXiK9Jg== X-Received: by 2002:a1c:9911:: with SMTP id b17mr33546239wme.135.1593794854946; Fri, 03 Jul 2020 09:47:34 -0700 (PDT) Date: Fri, 3 Jul 2020 18:46:30 +0200 In-Reply-To: <20200619214305.562-1-maennich@google.com> Message-Id: <20200703164651.1510825-1-maennich@google.com> Mime-Version: 1.0 References: <20200619214305.562-1-maennich@google.com> X-Mailer: git-send-email 2.27.0.212.ge8ba1cc988-goog Subject: [PATCH v2 00/21] Refactor (k)symtab reader To: libabigail@sourceware.org X-Spam-Status: No, score=-18.7 required=5.0 tests=BAYES_00, DKIMWL_WL_MED, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libabigail@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Mailing list of the Libabigail project List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-Patchwork-Original-From: Matthias Maennich via Libabigail From: =?utf-8?q?Matthias_M=C3=A4nnich?= Reply-To: Matthias Maennich Cc: maennich@google.com, kernel-team@android.com Errors-To: libabigail-bounces@sourceware.org Sender: "Libabigail" The current implementation that reads the symtab and the ksymtab has grown over time from simple symtab reading to way more complex ksymtab reading including taking care of little details like position relative relocations, symbol namespaces, etc. Yet, more features are coming to the Linux kernels that make this parsing even more tricky: Further changes to the ksymtab layout and different needs to lookup symbols caused by features like LTO (causing RELA relocations in the ksymtab entries) and CFI (causing additional jump table symbols) that are highly confusing the meaning of ksymtab entries and make it increasingly challenging for a static analysis tool like libabigail to properly process the ksymtab values. This added complexity also adds more and more responsibilities to the read_context that already has a lot of different tasks to juggle. It gets increasingly difficult to ensure, further development in the dwarf reader can be done without subtly regressing existing functionality. Hence, attempt a refactoring (one could argue: rewrite, but a lot of functionality is just migrated out) of the symtab reading code. The first 2 commits set up some prerequisites, like a partial backport of std::optional and enabling std::bind and friends. Commit 3 and 4 modify abg-ir's elf_symbol to be able to carry 'is_suppressed' and 'is_in_ksymtab'. Commit 5 and 6 implement the new symtab reader. The abg-symtab-reader has been introduced as an instance decoupled from dwarf readers' read_context. This reduces the responsibilities of the dwarf reader and separates the functionality into a new compilation unit. It contains several components to make the main component 'symtab' easy to access and to query. Refer to the extensive commit message there for details. The actual core of the symtab reading has been taken as a base, but refactored where useful. The ksymtab reading could be simplified by processing the corresponding __ksymtab_* entries directly from symtab without the need to interpret the binary ksymtab sections. That also resolves issues with wrong ksymtab reading: Mapping from the ksymtab symbol address to the symtab entry might leave us with a non-main symbol and hence leads to incorrect results. E.g. symbols like strlen are implemented as __pi_strlen and are aliases to strlen in the kernel. Only by reading the ksymtab entries we can decide which symbol to keep. Otherwise we get indeterministic results. Furthermore, symbol whitelists might list one or the other leading to issues of suppressed symbols for which we might just see the wrong symbol and therefore suppress both from analysis. In addition, detecting the format of the ksymtab, requires the first entry to be a valid elf_symbol, which is not the case if filtered out via whitelist or suppression. Finally, features like CFI require name based lookup into the ksymtab and LTO with clang on aarch64 might make the ksymtab contain relocatable entries. This is additional complexity hitting the dwarf reader. Those are subtle issues that motivated this series. Conceptionally, the new reader works quite similar. Except for the way suppressions are applied: Instead of discarding symbols while reading, we flag symbols as suppressed and keep them around for lookup purposes. That resolves issues when dealing with symbol aliases. Commit 7 integrates the new symtab reader into the existing code - side by side with the current implementation. Commits 8 - 12 migrate more and more symtab users over to the new symtab reader, including the ksymtab functionality in commit 12 where the old implementation could be obsoleted. Commits 13 and 14 re-add the ppc64 support for ELFv1 binaries. Commits 15 and 16 remove now obsolete functionality and remove the now old implementation. Commit 17 adds additional tests for whitelisted symbols. Commit 18 and 19 address some flaws with aliasing in combination with suppressions (e.g. triggered from whitelists). Those are issues I was seeing in the current implementation as well, but could solve a bit easier with the new symtab reader. Commit 20 adds support for MODVERSIONS in the Linux kernel (CRC values). Commit 21 addresses a bug that leads to an assertion hit when reading XML with whitelisting that hides an aliased symbol. Performance testing has been done with an 'allmodconfig' kernel config. That is the worst case for kernels and representing the 'distribution kernel' use case. During those tests, no significant performance impact could be measured. In addition, various Android Kernels in various configurations have been tested with this. The earlier added tests for reading symtab and ksymtab oviously pass. v1 -> v2: - Commit 16 now also drops the obsolete ksymtab enums. - Commit 17+ are new (alias improvements, modversions) - rebased on top of current master Cheers, Matthias Matthias Maennich (21): abg-cxx-compat: add simplified version of std::optional abg-cxx-compat: more support: std::bind and friends abg-ir: elf_symbol: add is_in_ksymtab field abg-ir: elf_symbol: add is_suppressed field dwarf-reader split: create abg-symtab-reader.{h,cc} and test case Refactor ELF symbol table reading by adding a new symtab reader Integrate new symtab reader into corpus and read_context corpus: make get_(undefined_)?_(var|fun)_symbols use the new symtab corpus: make get_unreferenced_(function|variable)_symbols use the new symtab abg-reader: avoid using the (var|function)_symbol_map dwarf-reader: read_context: use new symtab in *_symbols_is_exported Switch kernel stuff over to new symtab and drop unused code abg-elf-helpers: migrate ppc64 specific helpers symtab_reader: add support for ppc64 ELFv1 binaries abg-corpus: remove symbol maps and their setters dwarf reader: drop now-unused code related to symbol table reading test-symtab: add tests for whitelisted functions symtab/dwarf-reader: allow hinting of main symbols for aliases dwarf-reader/writer: consider aliases when dealing with suppressions symtab: Add support for MODVERSIONS (CRC checksums) reader/symtab: Improve handling for suppressed aliases include/Makefile.am | 3 +- include/abg-corpus.h | 24 +- include/abg-cxx-compat.h | 100 + include/abg-dwarf-reader.h | 6 - include/abg-fwd.h | 8 + include/abg-ir.h | 53 +- include/abg-symtab-reader.h | 429 +++ src/Makefile.am | 1 + src/abg-corpus-priv.h | 57 +- src/abg-corpus.cc | 645 ++--- src/abg-dwarf-reader.cc | 2437 ++--------------- src/abg-elf-helpers.cc | 186 ++ src/abg-elf-helpers.h | 8 + src/abg-ir.cc | 194 +- src/abg-reader.cc | 58 +- src/abg-reporter-priv.cc | 18 +- src/abg-symtab-reader.cc | 494 ++++ src/abg-tools-utils.cc | 13 - src/abg-writer.cc | 55 +- tests/Makefile.am | 4 + tests/data/Makefile.am | 31 +- .../test-missing-alias-report.txt | 0 .../test-abidiff-exit/test-missing-alias.abi | 12 + .../test-missing-alias.suppr | 4 + ...ibtirpc.so.report.txt => empty-report.txt} | 0 .../test-abidiff/test-PR24552-report0.txt | 3 - tests/data/test-abidiff/test-crc-0.xml | 1601 +++++++++++ tests/data/test-abidiff/test-crc-1.xml | 1601 +++++++++++ tests/data/test-abidiff/test-crc-2.xml | 1601 +++++++++++ tests/data/test-abidiff/test-crc-report.txt | 9 + .../test-abidiff/test-empty-corpus-report.txt | 3 - .../data/test-annotate/test15-pr18892.so.abi | 918 +++---- ...19-pr19023-libtcmalloc_and_profiler.so.abi | 60 +- tests/data/test-annotate/test2.so.abi | 12 +- tests/data/test-annotate/test3.so.abi | 6 +- tests/data/test-diff-dwarf/test12-report.txt | 7 + .../test42-PR21296-clanggcc-report0.txt | 4 +- ...bb-4.3-3.20141204.fc23.x86_64-report-0.txt | 6 +- ...bb-4.3-3.20141204.fc23.x86_64-report-1.txt | 6 +- .../test23-alias-filter-4.suppr | 4 +- .../test23-alias-filter-report-0.txt | 4 +- .../test23-alias-filter-report-2.txt | 4 +- .../PR22015-libboost_iostreams.so.abi | 48 +- .../test-read-dwarf/PR22122-libftdc.so.abi | 6 +- .../data/test-read-dwarf/PR25007-sdhci.ko.abi | 77 +- .../test-read-dwarf/test10-pr18818-gcc.so.abi | 192 +- .../test-read-dwarf/test11-pr18828.so.abi | 516 ++-- .../test-read-dwarf/test12-pr18844.so.abi | 60 +- .../test-read-dwarf/test15-pr18892.so.abi | 918 +++---- .../test-read-dwarf/test16-pr18904.so.abi | 964 +++---- ...19-pr19023-libtcmalloc_and_profiler.so.abi | 60 +- tests/data/test-read-dwarf/test2.so.abi | 12 +- tests/data/test-read-dwarf/test2.so.hash.abi | 12 +- .../test22-pr19097-libstdc++.so.6.0.17.so.abi | 878 +++--- .../test-read-dwarf/test3-alias-1.so.hash.abi | 14 + .../data/test-read-dwarf/test3-alias-1.suppr | 3 + .../test-read-dwarf/test3-alias-2.so.hash.abi | 18 + .../data/test-read-dwarf/test3-alias-2.suppr | 3 + .../test-read-dwarf/test3-alias-3.so.hash.abi | 14 + .../data/test-read-dwarf/test3-alias-3.suppr | 3 + .../test-read-dwarf/test3-alias-4.so.hash.abi | 8 + .../data/test-read-dwarf/test3-alias-4.suppr | 3 + tests/data/test-read-dwarf/test3.so.abi | 6 +- tests/data/test-read-dwarf/test3.so.hash.abi | 6 +- tests/data/test-read-write/test-crc.xml | 10 + tests/data/test-symtab/basic/aliases.c | 13 + tests/data/test-symtab/basic/aliases.so | Bin 0 -> 17176 bytes tests/data/test-symtab/basic/no_debug_info.c | 2 +- tests/data/test-symtab/basic/no_debug_info.so | Bin 15360 -> 15544 bytes .../one_function_one_variable_all.whitelist | 3 + ...e_function_one_variable_function.whitelist | 2 + ...function_one_variable_irrelevant.whitelist | 2 + ...e_function_one_variable_variable.whitelist | 2 + .../test-symtab/kernel-modversions/Makefile | 19 + .../kernel-modversions/one_of_each.c | 1 + .../kernel-modversions/one_of_each.ko | Bin 0 -> 131760 bytes tests/test-abidiff-exit.cc | 9 + tests/test-abidiff.cc | 34 +- tests/test-cxx-compat.cc | 51 + tests/test-read-dwarf.cc | 32 + tests/test-read-write.cc | 6 + tests/test-symtab-reader.cc | 53 + tests/test-symtab.cc | 195 +- tools/abidw.cc | 2 - 84 files changed, 9724 insertions(+), 5222 deletions(-) create mode 100644 include/abg-symtab-reader.h create mode 100644 src/abg-symtab-reader.cc create mode 100644 tests/data/test-abidiff-exit/test-missing-alias-report.txt create mode 100644 tests/data/test-abidiff-exit/test-missing-alias.abi create mode 100644 tests/data/test-abidiff-exit/test-missing-alias.suppr rename tests/data/test-abidiff/{test-PR18166-libtirpc.so.report.txt => empty-report.txt} (100%) delete mode 100644 tests/data/test-abidiff/test-PR24552-report0.txt create mode 100644 tests/data/test-abidiff/test-crc-0.xml create mode 100644 tests/data/test-abidiff/test-crc-1.xml create mode 100644 tests/data/test-abidiff/test-crc-2.xml create mode 100644 tests/data/test-abidiff/test-crc-report.txt delete mode 100644 tests/data/test-abidiff/test-empty-corpus-report.txt create mode 100644 tests/data/test-read-dwarf/test3-alias-1.so.hash.abi create mode 100644 tests/data/test-read-dwarf/test3-alias-1.suppr create mode 100644 tests/data/test-read-dwarf/test3-alias-2.so.hash.abi create mode 100644 tests/data/test-read-dwarf/test3-alias-2.suppr create mode 100644 tests/data/test-read-dwarf/test3-alias-3.so.hash.abi create mode 100644 tests/data/test-read-dwarf/test3-alias-3.suppr create mode 100644 tests/data/test-read-dwarf/test3-alias-4.so.hash.abi create mode 100644 tests/data/test-read-dwarf/test3-alias-4.suppr create mode 100644 tests/data/test-read-write/test-crc.xml create mode 100644 tests/data/test-symtab/basic/aliases.c create mode 100755 tests/data/test-symtab/basic/aliases.so create mode 100644 tests/data/test-symtab/basic/one_function_one_variable_all.whitelist create mode 100644 tests/data/test-symtab/basic/one_function_one_variable_function.whitelist create mode 100644 tests/data/test-symtab/basic/one_function_one_variable_irrelevant.whitelist create mode 100644 tests/data/test-symtab/basic/one_function_one_variable_variable.whitelist create mode 100644 tests/data/test-symtab/kernel-modversions/Makefile create mode 120000 tests/data/test-symtab/kernel-modversions/one_of_each.c create mode 100644 tests/data/test-symtab/kernel-modversions/one_of_each.ko create mode 100644 tests/test-symtab-reader.cc