From patchwork Thu Oct 16 12:07:46 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Gang X-Patchwork-Id: 3245 Received: (qmail 27200 invoked by alias); 16 Oct 2014 12:02:09 -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 27141 invoked by uid 89); 16 Oct 2014 12:02:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-pd0-f175.google.com Received: from mail-pd0-f175.google.com (HELO mail-pd0-f175.google.com) (209.85.192.175) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Thu, 16 Oct 2014 12:02:06 +0000 Received: by mail-pd0-f175.google.com with SMTP id v10so3133347pde.20 for ; Thu, 16 Oct 2014 05:02:05 -0700 (PDT) X-Received: by 10.68.220.133 with SMTP id pw5mr729132pbc.129.1413460923946; Thu, 16 Oct 2014 05:02:03 -0700 (PDT) Received: from ShengShiZhuChengdeMacBook-Pro.local ([124.126.239.21]) by mx.google.com with ESMTPSA id c2sm975448pdl.14.2014.10.16.05.01.55 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Oct 2014 05:02:02 -0700 (PDT) Message-ID: <543FB512.60607@gmail.com> Date: Thu, 16 Oct 2014 20:07:46 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: palves@redhat.com, mark.kettenis@xs4all.nl, Iain Buclaw , Joel Brobecker , gdb-patches@sourceware.org Subject: [PATCH v3] gdb/i387-tdep.c: Avoid warning for "-Werror=strict-overflow" gdb requires "-Werror", and I387_ST0_REGNUM (tdep) is 'variable', then compiler can think that I387_ST0_REGNUM (tdep) may be a large number to add a constant value, which may cause issue, so report warning. Need fix this warning, and still keep the code clear enough for readers (I387_NUM_REGS is much clearer than I387_XMM0_REGNUM). The related warning under Darwin with gnu built gcc: gcc -g -O2 -I. -I../../binutils-gdb/gdb -I../../binutils-gdb/gdb/common -I../../binutils-gdb/gdb/config -DLOCALEDIR="\"/usr/local/share/locale\"" -DHAVE_CONFIG_H -I../../binutils-gdb/gdb/../include/opcode -I../../binutils-gdb/gdb/../opcodes/.. -I../../binutils-gdb/gdb/../readline/.. -I../bfd -I../../binutils-gdb/gdb/../bfd -I../../binutils-gdb/gdb/../include -I../libdecnumber -I../../binutils-gdb/gdb/../libdecnumber -I../../binutils-gdb/gdb/gnulib/import -Ibuild-gnulib/import -DTUI=1 -D_THREAD_SAFE -I/usr/local/Cellar/guile/2.0.11/include/guile/2.0 -I/usr/local/Cellar/gmp/6.0.0a/include -I/usr/local/Cellar/readline/6.3.5/include -I/usr/local/Cellar/bdw-gc/7.2e/include -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -Wall -Wdeclaration-after-statement -Wpointer-arith -Wpointer-sign -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wmissing-protot ypes -Wdeclaration-after-statement -Wempty-body -Wmissing-parameter-type -Wold-style-declaration -Wold-style-definition -Wformat-nonliteral -Werror -c -o i387-tdep.o -MT i387-tdep.o -MMD -MP -MF .deps/i387-tdep.Tpo ../../binutils-gdb/gdb/i387-tdep.c ../../binutils-gdb/gdb/i387-tdep.c: In function 'i387_supply_fsave': ../../binutils-gdb/gdb/i387-tdep.c:447:1: error: assuming signed overflow does not occur when assuming that (X + c) >= X is always true [-Werror=strict-overflow] i387_supply_fsave (struct regcache *regcache, int regnum, const void *fsave) ^ ../../binutils-gdb/gdb/i387-tdep.c: In function 'i387_collect_fsave': ../../binutils-gdb/gdb/i387-tdep.c:502:1: error: assuming signed overflow does not occur when assuming that (X + c) >= X is always true [-Werror=strict-overflow] i387_collect_fsave (const struct regcache *regcache, int regnum, void *fsave) ^ cc1: all warnings being treated as errors Also give related comment for it, or other code readers may doubt why need 'end'. 2014-10-13 Chen Gang * i387-tdep.c (i387_supply_fsave): Avoid warning for "-Werror=strict-overflow" --- gdb/i387-tdep.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/gdb/i387-tdep.c b/gdb/i387-tdep.c index d66ac6a..f39c090 100644 --- a/gdb/i387-tdep.c +++ b/gdb/i387-tdep.c @@ -450,11 +450,13 @@ i387_supply_fsave (struct regcache *regcache, int regnum, const void *fsave) struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); const gdb_byte *regs = fsave; - int i; + int i, end; gdb_assert (tdep->st0_regnum >= I386_ST0_REGNUM); - for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++) + /* Avoid -Werror=strict-overflow for (X + c) >= X, so use 'end' */ + end = I387_ST0_REGNUM (tdep) + I387_NUM_REGS; + for (i = I387_ST0_REGNUM (tdep); i < end; i++) if (regnum == -1 || regnum == i) { if (fsave == NULL) @@ -503,11 +505,13 @@ i387_collect_fsave (const struct regcache *regcache, int regnum, void *fsave) { struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache)); gdb_byte *regs = fsave; - int i; + int i, end; gdb_assert (tdep->st0_regnum >= I386_ST0_REGNUM); - for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++) + /* Avoid -Werror=strict-overflow for (X + c) >= X, so use 'end' */ + end = I387_ST0_REGNUM (tdep) + I387_NUM_REGS; + for (i = I387_ST0_REGNUM (tdep); i < end; i++) if (regnum == -1 || regnum == i) { /* Most of the FPU control registers occupy only 16 bits in