From patchwork Wed Jan 25 08:38:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yao Qi X-Patchwork-Id: 19018 Received: (qmail 51134 invoked by alias); 25 Jan 2017 08:38:41 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 51043 invoked by uid 89); 25 Jan 2017 08:38:41 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM, SPF_PASS autolearn=no version=3.3.2 spammy=H*RU:74.125.83.66, Hx-spam-relays-external:74.125.83.66, H*MI:sk:1484560, *myaddr X-HELO: mail-pg0-f66.google.com Received: from mail-pg0-f66.google.com (HELO mail-pg0-f66.google.com) (74.125.83.66) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 25 Jan 2017 08:38:30 +0000 Received: by mail-pg0-f66.google.com with SMTP id 194so19104230pgd.0 for ; Wed, 25 Jan 2017 00:38:29 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=dNZ/qEWPHfEBRLhPgRi/I3YD/spICf2MGZzaDa3ePtk=; b=I70QoHSvDAkeeGhxA3eCWpgd19U0pJXvBqBsK1Yw40cd6/6qkjl/UAgkKdUXbNt2+h 5f/neTKzakLGE5jfv8TtWGm4NZIKLH9wNX4GwtdkHxnJjALJ8TmM/G/N96wfH2mNVB8p 4TIa1pwK3e1ko96wQKisps04nc++RNQ6t6i5sO8GQoFmm6dL4ozht/OHxIg19Kpk0WUQ HjpAx4TP0LebN0NlC3NFN/8DJItsgixSoJ7u8MoezIESFAZYEt/ErpGDBLiCTtdt1GKL nazDEoLd2xzFRt46+xtegqw1Sa+A7K/u1rLB9iMmFEYhaQfu75hVGtcTh+8LS3yG3ZZE kZag== X-Gm-Message-State: AIkVDXLe1CtwoZzu1QtGXPMs/DkiDr5dgv2eRJJ7KTPA7P66/PzbKD6Q+gJCoUVPbTuHJg== X-Received: by 10.99.223.5 with SMTP id u5mr46402612pgg.58.1485333508417; Wed, 25 Jan 2017 00:38:28 -0800 (PST) Received: from E107787-LIN.cambridge.arm.com (gcc1-power7.osuosl.org. [140.211.15.137]) by smtp.gmail.com with ESMTPSA id x2sm50271378pfa.71.2017.01.25.00.38.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 25 Jan 2017 00:38:27 -0800 (PST) From: Yao Qi X-Google-Original-From: Yao Qi To: gdb-patches@sourceware.org Subject: [PATCH 6/6] Don't throw exception in dis_asm_memory_error Date: Wed, 25 Jan 2017 08:38:00 +0000 Message-Id: <1485333480-20515-7-git-send-email-yao.qi@linaro.org> In-Reply-To: <1485333480-20515-1-git-send-email-yao.qi@linaro.org> References: <1484560977-8693-1-git-send-email-yao.qi@linaro.org> <1485333480-20515-1-git-send-email-yao.qi@linaro.org> X-IsSubscribed: yes Hi, GDB calls some APIs from opcodes to do disassembly and provide some call backs. This model makes troubles on C++ exception unwinding, because GDB is a C++ program, and opcodes is still compiled as C. As we can see, frame #10 and #12 are C++, while #frame 11 is C, #10 0x0000000000544228 in memory_error (err=TARGET_XFER_E_IO, memaddr=) at ../../binutils-gdb/gdb/corefile.c:237 #11 0x00000000006b0a54 in print_insn_aarch64 (pc=0, info=0xffffffffeeb0) at ../../binutils-gdb/opcodes/aarch64-dis.c:3185 #12 0x0000000000553590 in gdb_pretty_print_insn (gdbarch=gdbarch@entry=0xbbceb0, uiout=uiout@entry=0xbc73d0, di=di@entry=0xffffffffeeb0, insn=0xffffffffed40, insn@entry=0xffffffffed90, flags=flags@entry=0, C++ exception unwinder can't go across frame #11 unless it has unwind table. However, C program on many architectures doesn't have it in default. As a result, GDB aborts, which is described in PR 20939. This is not the first time we see this kind of problem. We've had a commit 89525768cd086a0798a504c81fdf7ebcd4c904e1 "Propagate GDB/C++ exceptions across readline using sj/lj-based TRY/CATCH". We can fix the disassembly bug in a similar way, this is the option one. Since opcodes is built with gdb, we fix this problem in a different way as we did for the same issue with readline. Instead of throwing exception in dis_asm_memory_error, we record the failed memory address, and throw exception when GDB returns from opcodes disassemblers. gdb: 2017-01-24 Yao Qi Pedro Alves PR gdb/20939 * disasm.c (gdb_disassembler::dis_asm_memory_error): Don't call memory_error, save memaddr instead. (gdb_disassembler::print_insn): If gdbarch_print_insn returns negative, cal memory_error. * disasm.h (gdb_disassembler) : New field. gdb/testsuite: 2017-01-24 Yao Qi * gdb.base/all-architectures.exp.in (do_arch_tests): Test disassemble on address 0. --- gdb/disasm.c | 13 +++++++++++-- gdb/disasm.h | 1 + gdb/testsuite/gdb.base/all-architectures.exp.in | 5 +++++ 3 files changed, 17 insertions(+), 2 deletions(-) diff --git a/gdb/disasm.c b/gdb/disasm.c index b58da0f..897f2f1 100644 --- a/gdb/disasm.c +++ b/gdb/disasm.c @@ -135,7 +135,10 @@ void gdb_disassembler::dis_asm_memory_error (int err, bfd_vma memaddr, struct disassemble_info *info) { - memory_error (TARGET_XFER_E_IO, memaddr); + gdb_disassembler *self + = static_cast(info->application_data); + + self->m_err_memaddr = memaddr; } /* Wrapper of print_address. */ @@ -765,7 +768,8 @@ fprintf_disasm (void *stream, const char *format, ...) gdb_disassembler::gdb_disassembler (struct gdbarch *gdbarch, struct ui_file *file, di_read_memory_ftype read_memory_func) - : m_gdbarch (gdbarch) + : m_gdbarch (gdbarch), + m_err_memaddr (0) { init_disassemble_info (&m_di, file, fprintf_disasm); m_di.flavour = bfd_target_unknown_flavour; @@ -792,8 +796,13 @@ int gdb_disassembler::print_insn (CORE_ADDR memaddr, int *branch_delay_insns) { + m_err_memaddr = 0; + int length = gdbarch_print_insn (arch (), memaddr, &m_di); + if (length < 0) + memory_error (TARGET_XFER_E_IO, m_err_memaddr); + if (branch_delay_insns != NULL) { if (m_di.insn_info_valid) diff --git a/gdb/disasm.h b/gdb/disasm.h index c6cb13b..7bbfa31 100644 --- a/gdb/disasm.h +++ b/gdb/disasm.h @@ -66,6 +66,7 @@ private: /* Stores data required for disassembling instructions in opcodes. */ struct disassemble_info m_di; + CORE_ADDR m_err_memaddr; static int dis_asm_read_memory (bfd_vma memaddr, gdb_byte *myaddr, unsigned int len, diff --git a/gdb/testsuite/gdb.base/all-architectures.exp.in b/gdb/testsuite/gdb.base/all-architectures.exp.in index c7615ac..b07caf5 100644 --- a/gdb/testsuite/gdb.base/all-architectures.exp.in +++ b/gdb/testsuite/gdb.base/all-architectures.exp.in @@ -152,6 +152,11 @@ proc print_floats {} { proc do_arch_tests {} { print_floats + + # GDB can't access memory because there is no loaded executable + # nor live inferior. + gdb_test_internal "disassemble 0x0,+4" \ + "Cannot access memory at address 0x0" } # Given we can't change arch, osabi, endianness, etc. atomically, we