From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 86811 invoked by alias); 21 Jul 2016 16:59:45 -0000 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 Received: (qmail 86801 invoked by uid 89); 21 Jul 2016 16:59:44 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 21 Jul 2016 16:59:34 +0000 Received: from svr-orw-fem-02x.mgc.mentorg.com ([147.34.96.206] helo=SVR-ORW-FEM-02.mgc.mentorg.com) by relay1.mentorg.com with esmtp id 1bQHJs-0004Bh-6a from Don_Breazeal@mentor.com ; Thu, 21 Jul 2016 09:59:32 -0700 Received: from [172.30.3.44] (147.34.91.1) by SVR-ORW-FEM-02.mgc.mentorg.com (147.34.96.168) with Microsoft SMTP Server (TLS) id 14.3.224.2; Thu, 21 Jul 2016 09:59:32 -0700 Subject: Re: [PING] [PATCH v2] Fix -var-update for registers in frames 1 and up To: , References: <1465854882-42527-1-git-send-email-donb@codesourcery.com> <57680C62.5060807@codesourcery.com> <5783B1BE.7010206@codesourcery.com> <578FE7E6.5070507@codesourcery.com> From: Don Breazeal Message-ID: <5790FF6C.9040003@codesourcery.com> Date: Thu, 21 Jul 2016 16:59:00 -0000 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <578FE7E6.5070507@codesourcery.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-07/txt/msg00266.txt.bz2 Hi, see below, On 7/20/2016 2:06 PM, Don Breazeal wrote: > ping > > On 7/11/2016 7:48 AM, Don Breazeal wrote: >> >> ping >> >> On 6/20/2016 8:31 AM, Don Breazeal wrote: >>> On 6/13/2016 2:54 PM, Don Breazeal wrote: >>>> This is an updated version of a patch to fix access to registers >>>> for frames other than the current frame via var-update. The piece >>>> of the patch affecting GDB proper has been completely re-written. >>>> It changes the initialization of varobj->root->frame in varobj_create >>>> so that existing mechanisms (with minimal changes) select the correct >>>> frame and provide correct register values from -var-update. >>>> >>>> In addition, the new test for this functionality has been expanded >>>> to cover an analogous case using floating variable objects, and >>>> several tests have been updated to account for the fact that with >>>> the new initialization, -var-create and -var-list-children now >>>> provide a thread-id field where previously they didn't. >>>> >>>> Thanks >>>> --Don >>>> >>>> ------------ >>>> This patch fixes a problem with using the MI -var-update command >>>> to access the values of registers in frames other than the current >>>> frame. The patch includes a test that demonstrates the problem: >>>> >>>> * run so there are several frames on the stack >>>> * create a fixed varobj for $pc in each frame, #'s 1 and above >>>> * step one instruction, to modify the value of $pc >>>> * call -var-update for each of the previously created varobjs >>>> to verify that they are not reported as having changed. >>>> >>>> Without the patch, the -var-update command reported that $pc for all >>>> frames 1 and above had changed to the value of $pc in frame 0. >>>> >>>> When a varobj is created by -var-create, varobj->root->frame should >>>> be set to specified frame. Then for a subsequent -var-update, >>>> varobj.c:check_scope can use varobj->root->frame to select the >>>> right frame based on the type of varobj. >>>> >>>> The problem is that for register expressions varobj->root->frame is not >>>> set correctly. This frame tracking is done using the global >>>> 'innermost_block' which is set in the various parser files (for example >>>> c-exp.y). However, this is not set for register expressions. >>>> >>>> The fix is to change the initialization of innermost_block in >>>> varobj_create from NULL to the global block, as returned by >>>> block_global_block. Then varobj_create sets varobj->root->frame >>>> for register varobjs, and value_of_root_1 can check for the >>>> global block when determining whether the variable is in-scope >>>> and select the frame appropriately. >>>> >>>> A side-effect of this change is that for register varobjs and some >>>> global variable varobjs, the output of -var-create now includes the >>>> thread-id field. The rationale for this is as follow: if we ask for a >>>> particular expression in a particular frame, that implies a particular >>>> thread. Thus including the thread-id is correct behavior, and the >>>> test results have been updated accordingly. >>>> >>>> In addition there is a new test, gdb.mi/mi-frame-regs.exp, which >>>> performs the test described in the bullet list above as well as a >>>> similar test using a floating variable object to represent $pc. >>>> >>>> We attempted a couple alternative solutions: >>>> * a special case in varobj_update to select the frame was not ideal >>>> because it didn't use the existing mechanisms to select the frame. >>>> * setting innermost_block in write_dollar_variable had side-effects >>>> in the CLI that would have required special case code. >>>> >>>> Tested on x86_64 Linux native, no regressions. >>>> >>>> gdb/testsuite/ChangeLog: >>>> 2016-06-13 Don Breazeal >>>> >>>> * gdb.ada/mi_interface.exp: Add thread-id field to expected >>>> output of -var-create and -var-list-children. >>>> * gdb.ada/mi_var_array.exp: Add thread-id field to expected >>>> output of -var-list-children. >>>> * gdb.mi/mi-break.exp (test_error): Add thread-id field to >>>> expected output of -var-create. >>>> * gdb.mi/mi-frame-regs.exp: New test script. >>>> * gdb.mi/mi-var-cmd.exp: Add thread-id field to expected >>>> output of -var-create. >>>> * gdb.mi/mi-var-create-rtti.exp: Likewise. >>>> >>>> gdb/ChangeLog: >>>> 2016-06-13 Don Breazeal >>>> Andrew Burgess >>>> >>>> * varobj.c (varobj_create): Initialize innermost_block to >>>> the global block instead of NULL. >>>> (new_root_variable): Initialize the thread_id and next >>>> fields. >>>> (value_of_root_1): Set within_scope if the variable's >>>> valid_block field is the global block. >>>> >>>> --- >>>> gdb/testsuite/gdb.ada/mi_interface.exp | 4 +- >>>> gdb/testsuite/gdb.ada/mi_var_array.exp | 2 +- >>>> gdb/testsuite/gdb.mi/mi-break.exp | 2 +- >>>> gdb/testsuite/gdb.mi/mi-frame-regs.exp | 183 ++++++++++++++++++++++++++++ >>>> gdb/testsuite/gdb.mi/mi-var-cmd.exp | 4 +- >>>> gdb/testsuite/gdb.mi/mi-var-create-rtti.exp | 2 +- >>>> gdb/varobj.c | 8 +- >>>> 7 files changed, 196 insertions(+), 9 deletions(-) >>>> >>>> diff --git a/gdb/testsuite/gdb.ada/mi_interface.exp b/gdb/testsuite/gdb.ada/mi_interface.exp >>>> index 6000ec8..b948cd5 100644 >>>> --- a/gdb/testsuite/gdb.ada/mi_interface.exp >>>> +++ b/gdb/testsuite/gdb.ada/mi_interface.exp >>>> @@ -44,9 +44,9 @@ mi_continue_to_line \ >>>> "stop at start of main Ada procedure" >>>> >>>> mi_gdb_test "-var-create ggg1 * ggg1" \ >>>> - "\\^done,name=\"ggg1\",numchild=\"1\",value=\"{...}\",type=\" pck.gadatatype\",has_more=\"0\"" \ >>>> + "\\^done,name=\"ggg1\",numchild=\"1\",value=\"{...}\",type=\" pck.gadatatype\",thread-id=\"1\",has_more=\"0\"" \ >>>> "Create ggg1 varobj" >>>> >>>> mi_gdb_test "-var-list-children 1 ggg1" \ >>>> - "\\^done,numchild=\"1\",children=\\\[child={name=\"ggg1.i\",exp=\"i\",numchild=\"0\",value=\"42\",type=\"integer\"}\\\],has_more=\"0\"" \ >>>> + "\\^done,numchild=\"1\",children=\\\[child={name=\"ggg1.i\",exp=\"i\",numchild=\"0\",value=\"42\",type=\"integer\",thread-id=\"1\"}\\\],has_more=\"0\"" \ >>>> "list ggg1's children" >>>> diff --git a/gdb/testsuite/gdb.ada/mi_var_array.exp b/gdb/testsuite/gdb.ada/mi_var_array.exp >>>> index c648e7e..c02d4c9 100644 >>>> --- a/gdb/testsuite/gdb.ada/mi_var_array.exp >>>> +++ b/gdb/testsuite/gdb.ada/mi_var_array.exp >>>> @@ -48,5 +48,5 @@ mi_gdb_test "-var-create vta * vta" \ >>>> "Create bt varobj" >>>> >>>> mi_gdb_test "-var-list-children vta" \ >>>> - "\\^done,numchild=\"2\",children=\\\[child={name=\"vta.n\",exp=\"n\",numchild=\"0\",type=\"bar\\.int\"},child={name=\"vta.f\",exp=\"f\",numchild=\"0\",type=\"array \\(1 .. n\\) of character\"}\\\],.*" \ >>>> + "\\^done,numchild=\"2\",children=\\\[child={name=\"vta.n\",exp=\"n\",numchild=\"0\",type=\"bar\\.int\",thread-id=\"1\"},child={name=\"vta.f\",exp=\"f\",numchild=\"0\",type=\"array \\(1 .. n\\) of character\",thread-id=\"1\"}\\\],.*" \ >>>> "list vta's children" >>>> diff --git a/gdb/testsuite/gdb.mi/mi-break.exp b/gdb/testsuite/gdb.mi/mi-break.exp >>>> index 85f328d..bdd43e0 100644 >>>> --- a/gdb/testsuite/gdb.mi/mi-break.exp >>>> +++ b/gdb/testsuite/gdb.mi/mi-break.exp >>>> @@ -213,7 +213,7 @@ proc test_error {} { >>>> # containing function call, the internal breakpoint created to handle >>>> # function call would be reported, messing up MI output. >>>> mi_gdb_test "-var-create V * return_1()" \ >>>> - "\\^done,name=\"V\",numchild=\"0\",value=\"1\",type=\"int\",has_more=\"0\"" \ >>>> + "\\^done,name=\"V\",numchild=\"0\",value=\"1\",type=\"int\",thread-id=\"1\",has_more=\"0\"" \ >>>> "create varobj for function call" >>>> >>>> mi_gdb_test "-var-update *" \ >>>> diff --git a/gdb/testsuite/gdb.mi/mi-frame-regs.exp b/gdb/testsuite/gdb.mi/mi-frame-regs.exp >>>> new file mode 100644 >>>> index 0000000..45f81d6 >>>> --- /dev/null >>>> +++ b/gdb/testsuite/gdb.mi/mi-frame-regs.exp >>>> @@ -0,0 +1,183 @@ >>>> +# Copyright 1999-2016 Free Software Foundation, Inc. >>>> + >>>> +# This program is free software; you can redistribute it and/or modify >>>> +# it under the terms of the GNU General Public License as published by >>>> +# the Free Software Foundation; either version 3 of the License, or >>>> +# (at your option) any later version. >>>> +# >>>> +# This program is distributed in the hope that it will be useful, >>>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of >>>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >>>> +# GNU General Public License for more details. >>>> +# >>>> +# You should have received a copy of the GNU General Public License >>>> +# along with this program. If not, see . >>>> + >>>> +# Test essential Machine interface (MI) operations >>>> +# >>>> +# Verify that -var-update will provide the correct values for floating >>>> +# and fixed varobjs that represent the pc register. >>>> +# >>>> + >>>> +load_lib mi-support.exp >>>> +set MIFLAGS "-i=mi" >>>> + >>>> +standard_testfile basics.c >>>> + >>>> +if {[gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" \ >>>> + executable {debug}] != "" } then { >>>> + untested mi-frame-regs.exp >>>> + return -1 >>>> +} >>>> + >>>> +# Return the address of the specified breakpoint. >>>> + >>>> +proc breakpoint_address {bpnum} { >>>> + global hex >>>> + global expect_out >>>> + global mi_gdb_prompt >>>> + >>>> + send_gdb "info breakpoint $bpnum\n" >>>> + gdb_expect { >>>> + -re ".*($hex).*$mi_gdb_prompt$" { >>>> + return $expect_out(1,string) >>>> + } >>>> + -re ".*$mi_gdb_prompt$" { >>>> + return "" >>>> + } >>>> + timeout { >>>> + return "" >>>> + } >>>> + } >>>> +} >>>> + >>>> +# Test that a floating varobj representing $pc will provide the >>>> +# correct value via -var-update as the program stops at >>>> +# breakpoints in different functions. >>>> + >>>> +proc do_floating_varobj_test {} { >>>> + global srcfile >>>> + global hex >>>> + global expect_out >>>> + >>>> + gdb_exit >>>> + if {[mi_gdb_start]} then { >>>> + continue >>>> + } >>>> + >>>> + with_test_prefix "floating" { >>>> + mi_run_to_main >>>> + >>>> + # Create a floating varobj for $pc. >>>> + mi_gdb_test "-var-create --thread 1 --frame 0 - @ \$pc" \ >>>> + "\\^done,.*value=\"$hex.*" \ >>>> + "create varobj for pc in frame 0" >>>> + >>>> + set nframes 4 >>>> + for {set i 1} {$i < $nframes} {incr i} { >>>> + >>>> + # Run to a breakpoint in each callee function in succession. >>>> + # Note that we can't use mi_runto because we need the >>>> + # breakpoint to be persistent, so we can use its address. >>>> + set bpnum [expr $i + 1] >>>> + mi_create_breakpoint \ >>>> + "basics.c:callee$i" \ >>>> + "insert breakpoint at basics.c:callee$i" \ >>>> + -number $bpnum -func callee$i -file ".*basics.c" >>>> + >>>> + mi_execute_to "exec-continue" "breakpoint-hit" \ >>>> + "callee$i" ".*" ".*${srcfile}" ".*" \ >>>> + { "" "disp=\"keep\"" } "breakpoint hit" >>>> + >>>> + # Get the value of $pc from the floating varobj. >>>> + mi_gdb_test "-var-update 1 var1" \ >>>> + "\\^done,.*value=\"($hex) .*" \ >>>> + "-var-update for frame $i" >>>> + set pcval $expect_out(3,string) >>>> + >>>> + # Get the address of the current breakpoint. >>>> + set bpaddr [breakpoint_address $bpnum] >>>> + if {$bpaddr == ""} then { >>>> + unresolved "get address of breakpoint $bpnum" >>>> + return >>>> + } >>>> + >>>> + # Check that the addresses are the same. >>>> + if {[expr $bpaddr != $pcval]} then { >>>> + fail "\$pc does not equal address of breakpoint" >>>> + } else { >>>> + pass "\$pc equals address of breakpoint" >>>> + } >>>> + } >>>> + } >>>> +} >>>> + >>>> +# Create a varobj for the pc register in each of the frames other >>>> +# than frame 0. >>>> + >>>> +proc var_create_regs {nframes} { >>>> + global hex >>>> + >>>> + for {set i 1} {$i < $nframes} {incr i} { >>>> + mi_gdb_test "-var-create --thread 1 --frame $i - \* \$pc" \ >>>> + "\\^done,.*value=\"$hex.*" \ >>>> + "create varobj for pc in frame $i" >>>> + } >>>> +} >>>> + >>>> +# Check that -var-update reports that the value of the pc register >>>> +# for each of the frames 1 and above is reported as unchanged. >>>> + >>>> +proc var_update_regs {nframes} { >>>> + >>>> + for {set i 1} {$i < $nframes} {incr i} { >>>> + mi_gdb_test "-var-update 1 var$i" \ >>>> + "\\^done,(changelist=\\\[\\\])" \ >>>> + "pc unchanged in -var-update for frame $i" >>>> + } >>>> +} >>>> + >>>> +# Test that fixed varobjs representing $pc in different stack frames >>>> +# will provide the correct value via -var-update after the program >>>> +# counter changes (without substantially changing the stack). >>>> + >>>> +proc do_fixed_varobj_test {} { >>>> + global srcfile >>>> + >>>> + gdb_exit >>>> + if {[mi_gdb_start]} then { >>>> + continue >>>> + } >>>> + >>>> + with_test_prefix "fixed" { >>>> + mi_run_to_main >>>> + >>>> + # Run to the function 'callee3' so we have several frames. >>>> + mi_create_breakpoint "basics.c:callee3" \ >>>> + "insert breakpoint at basics.c:callee3" \ >>>> + -number 2 -func callee3 -file ".*basics.c" >>>> + >>>> + mi_execute_to "exec-continue" "breakpoint-hit" \ >>>> + "callee3" ".*" ".*${srcfile}" ".*" \ >>>> + { "" "disp=\"keep\"" } "breakpoint hit" >>>> + >>>> + # At the breakpoint in callee3 there are 4 frames. Create a >>>> + # varobj for the pc in each of frames 1 and above. >>>> + set nframes 4 >>>> + var_create_regs $nframes >>>> + >>>> + # Step one instruction to change the program counter. >>>> + mi_execute_to "exec-next-instruction" "end-stepping-range" \ >>>> + "callee3" ".*" ".*${srcfile}" ".*" "" \ >>>> + "next instruction in callee3" >>>> + >>>> + # Check that -var-update reports that the values are unchanged. >>>> + var_update_regs $nframes >>>> + } >>>> +} >>>> + >>>> +do_fixed_varobj_test >>>> +do_floating_varobj_test >>>> + >>>> +mi_gdb_exit >>>> +return 0 >>>> diff --git a/gdb/testsuite/gdb.mi/mi-var-cmd.exp b/gdb/testsuite/gdb.mi/mi-var-cmd.exp >>>> index 558cd6c..68e3cf8 100644 >>>> --- a/gdb/testsuite/gdb.mi/mi-var-cmd.exp >>>> +++ b/gdb/testsuite/gdb.mi/mi-var-cmd.exp >>>> @@ -381,7 +381,7 @@ mi_gdb_test "-var-update *" \ >>>> "assign same value to func (update)" >>>> >>>> mi_gdb_test "-var-create array_ptr * array_ptr" \ >>>> - "\\^done,name=\"array_ptr\",numchild=\"1\",value=\"$hex \",type=\"int \\*\",has_more=\"0\"" \ >>>> + "\\^done,name=\"array_ptr\",numchild=\"1\",value=\"$hex \",type=\"int \\*\",thread-id=\"1\",has_more=\"0\"" \ >>>> "create global variable array_ptr" >>>> >>>> mi_gdb_test "-var-assign array_ptr array2" \ >>>> @@ -608,7 +608,7 @@ mi_check_varobj_value F 7 "check F inside callee" >>>> # A varobj we fail to read during -var-update should be considered >>>> # out of scope. >>>> mi_gdb_test "-var-create null_ptr * **0" \ >>>> - {\^done,name="null_ptr",numchild="0",value=".*",type="int",has_more="0"} \ >>>> + {\^done,name="null_ptr",numchild="0",value=".*",type="int",thread-id="1"has_more="0"} \ >>>> "create null_ptr" >>>> >>>> # Allow this to succeed, if address zero is readable, although it >>>> diff --git a/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp b/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp >>>> index 3bcb36c..a8cc76f 100644 >>>> --- a/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp >>>> +++ b/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp >>>> @@ -49,6 +49,6 @@ mi_gdb_test "-gdb-set print object on" ".*" >>>> # We use a explicit cast to (void *) as that is the >>>> # type that caused the bug this testcase is testing for. >>>> mi_gdb_test "-var-create sp1 * ((void*)\$sp)" \ >>>> - "\\^done,name=\"sp1\",numchild=\"0\",value=\"$hex\",type=\"void \\*\",has_more=\"0\"" \ >>>> + "\\^done,name=\"sp1\",numchild=\"0\",value=\"$hex\",type=\"void \\*\",thread-id=\"1\",has_more=\"0\"" \ >>>> "-var-create sp1 * \$sp" >>>> gdb_exit >>>> diff --git a/gdb/varobj.c b/gdb/varobj.c >>>> index 6f56cba..1e3f192 100644 >>>> --- a/gdb/varobj.c >>>> +++ b/gdb/varobj.c >>>> @@ -323,7 +323,7 @@ varobj_create (char *objname, >>>> } >>>> >>>> p = expression; >>>> - innermost_block = NULL; >>>> + innermost_block = block_global_block (block); >>>> /* Wrap the call to parse expression, so we can >>>> return a sensible error. */ >>>> TRY >>>> @@ -2103,6 +2103,8 @@ new_root_variable (void) >>>> var->root->floating = 0; >>>> var->root->rootvar = NULL; >>>> var->root->is_valid = 1; >>>> + var->root->thread_id = 0; >>>> + var->root->next = NULL; >>>> >>>> return var; >>>> } >>>> @@ -2268,7 +2270,9 @@ value_of_root_1 (struct varobj **var_handle) >>>> back_to = make_cleanup_restore_current_thread (); >>>> >>>> /* Determine whether the variable is still around. */ >>>> - if (var->root->valid_block == NULL || var->root->floating) >>>> + if (var->root->valid_block == NULL >>>> + || BLOCK_SUPERBLOCK (var->root->valid_block) == NULL >>>> + || var->root->floating) >>>> within_scope = 1; >>>> else if (var->root->thread_id == 0) >>>> { >>>> >>> >> > I've created PR mi/20395 for this issue and marked it with the Target Milestone 7.12. Since it's an issue of returning incorrect data I'm proposing that it's a blocker. thanks --Don