From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25078 invoked by alias); 31 May 2009 20:48:01 -0000 Received: (qmail 25070 invoked by uid 22791); 31 May 2009 20:48:00 -0000 X-SWARE-Spam-Status: No, hits=-2.7 required=5.0 tests=AWL,BAYES_00,SPF_PASS X-Spam-Check-By: sourceware.org Received: from e24smtp01.br.ibm.com (HELO e24smtp01.br.ibm.com) (32.104.18.85) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 31 May 2009 20:47:55 +0000 Received: from d24relay01.br.ibm.com (d24relay01.br.ibm.com [9.8.31.16]) by e24smtp01.br.ibm.com (8.13.1/8.13.1) with ESMTP id n4VL8ZVt000332 for ; Sun, 31 May 2009 18:08:35 -0300 Received: from d24av02.br.ibm.com (d24av02.br.ibm.com [9.18.232.47]) by d24relay01.br.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n4VLl4ql3563594 for ; Sun, 31 May 2009 18:47:04 -0300 Received: from d24av02.br.ibm.com (loopback [127.0.0.1]) by d24av02.br.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n4VKlofh015173 for ; Sun, 31 May 2009 17:47:50 -0300 Received: from [9.8.8.171] ([9.8.8.171]) by d24av02.br.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id n4VKloM8015022 for ; Sun, 31 May 2009 17:47:50 -0300 Subject: [RFC] Fix verification of changed values for big values. From: Thiago Jung Bauermann To: gdb-patches ml Content-Type: text/plain; charset="UTF-8" Date: Sun, 31 May 2009 20:48:00 -0000 Message-Id: <1243802866.26363.35.camel@hactar> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2009-05/txt/msg00670.txt.bz2 Hi, This is the fix that Sérgio mentioned on the thread about our progress on the BookE debug registers support. Right now, GDB calls value_equal when comparing the old and new values of a watchpoint. IMO this is not correct, since that function will call coerce_array and effectively just compare the addresses of arrays being watched. This patch introduces a new value comparison function which works in the mentioned case, and a testcase which fails without the patch and passes with it. Ok to commit? -- []'s Thiago Jung Bauermann IBM Linux Technology Center gdb/ * breakpoint.c (value_equal_watchpoint): New function. (watchpoint_check): Use value_equal_watchpoint instead of value_equal. gdb/testsuite/ * gdb.base/watchpoint.exp (test_watchpoint_in_big_blob): New function. (top level): Call test_watchpoint_in_big_blob. * gdb.base/watchpoint.c (buf): Change size to value too big for hardware watchpoints. (func3): Write to buf. Index: gdb.git/gdb/breakpoint.c =================================================================== --- gdb.git.orig/gdb/breakpoint.c 2009-05-31 17:05:44.000000000 -0300 +++ gdb.git/gdb/breakpoint.c 2009-05-31 17:19:29.000000000 -0300 @@ -2717,7 +2717,23 @@ watchpoints_triggered (struct target_wai #define BP_TEMPFLAG 1 #define BP_HARDWAREFLAG 2 -/* Check watchpoint condition. */ +/* Check watchpoint condition. We can't use value_equal because it coerces + an array to a pointer, thus comparing just the address of the array instead + of its contents. This is not what we want. */ + +static int +value_equal_watchpoint (struct value *arg1, struct value *arg2) +{ + struct type *type1, *type2; + + type1 = check_typedef (value_type (arg1)); + type2 = check_typedef (value_type (arg2)); + + return TYPE_CODE (type1) == TYPE_CODE (type2) + && TYPE_LENGTH (type1) == TYPE_LENGTH (type2) + && memcmp (value_contents (arg1), value_contents (arg2), + TYPE_LENGTH (type1)) == 0; +} static int watchpoint_check (void *p) @@ -2785,7 +2801,7 @@ watchpoint_check (void *p) fetch_watchpoint_value (b->exp, &new_val, NULL, NULL); if ((b->val != NULL) != (new_val != NULL) - || (b->val != NULL && !value_equal (b->val, new_val))) + || (b->val != NULL && !value_equal_watchpoint (b->val, new_val))) { if (new_val != NULL) { Index: gdb.git/gdb/testsuite/gdb.base/watchpoint.c =================================================================== --- gdb.git.orig/gdb/testsuite/gdb.base/watchpoint.c 2009-05-31 17:04:24.000000000 -0300 +++ gdb.git/gdb/testsuite/gdb.base/watchpoint.c 2009-05-31 17:16:35.000000000 -0300 @@ -30,7 +30,7 @@ int ival2 = -1; int ival3 = -1; int ival4 = -1; int ival5 = -1; -char buf[10]; +char buf[30]; struct foo { int val; @@ -95,6 +95,7 @@ func3 () x = 1; /* second x assignment */ y = 1; y = 2; + buf[26] = 3; } int Index: gdb.git/gdb/testsuite/gdb.base/watchpoint.exp =================================================================== --- gdb.git.orig/gdb/testsuite/gdb.base/watchpoint.exp 2009-05-31 17:04:24.000000000 -0300 +++ gdb.git/gdb/testsuite/gdb.base/watchpoint.exp 2009-05-31 17:17:04.000000000 -0300 @@ -678,6 +678,24 @@ proc test_inaccessible_watchpoint {} { } } +proc test_watchpoint_in_big_blob {} { + global gdb_prompt + + gdb_test "watch buf" ".*atchpoint \[0-9\]+: buf" + send_gdb "cont\n" + gdb_expect { + -re "Continuing.*\[Ww\]atchpoint.*buf.*Old value = .*$gdb_prompt $" { + pass "watchpoint on buf hit" + } + -re "Continuing.*$gdb_prompt $" { + fail "watchpoint on buf hit" + } + -re ".*$gdb_prompt $" { fail "watchpoint on buf hit" ; return } + timeout { fail "watchpoint on buf hit (timeout)" ; return } + eof { fail "watchpoint on buf hit (eof)" ; return } + } +} + # Start with a fresh gdb. gdb_exit @@ -842,6 +860,8 @@ if [initialize] then { } test_watchpoint_and_breakpoint + + test_watchpoint_in_big_blob } # Restore old timeout