[lldb-dev] issue with lldb-mi -var-update with pointers

[Abid, Hafiz via lldb-dev]

I see 2 problems here. CMICmdCmdVarUpdate::ExamineSBValueForChange seems to ignore the changes in in children
for pointer and references. It is easy enough to fix. The other issue is that we dont not print the changed child value.
For example, with the first issue fixed, I get 

-var-update 1 var0
^done,changelist=[{name="var0",value="0x00007fffffffed30",in_scope="true",type_changed="false",has_more="0"}]

This problem exist for aggregate types too. 

I think I can put the fix for the first problem if it will help you. Please let me know. 

Thanks,
Abid
________________________________________
From: lldb-dev <lldb-dev-bounces at lists.llvm.org> on behalf of Ted Woodward via lldb-dev <lldb-dev at lists.llvm.org>
Sent: Tuesday, May 30, 2017 9:50 PM
To: 'LLDB'
Subject: [lldb-dev] issue with lldb-mi -var-update with pointers

I have a simple testcase that modifies the value pointed to by an int *.
I've created a variable with -var-create, and then after the value has been
updated, check it with -var-update. -var-update returns no changes, but the
value has changed.

test.c:
#include <stdlib.h>

int main(void)
{
  int vec[] = {1, 2, 3, 4};
  int foo = 0;
  int *bar = &foo;
  int i = 0;

  for (i = 0; i < 4; i++)
    *bar += vec[i];

  return foo;
}

Commands:
-break-insert -t -f test.c:10
-break-insert -t -f test.c:13
-exec-run
-var-create --thread 1 --frame 0 - * bar
-var-list-children var0
-var-evaluate-expression var0.*bar
-exec-continue
 1 var0
-var-evaluate-expression var0.*bar


Output:
(gdb)
-var-create --thread 1 --frame 0 - * bar
^done,name="var0",numchild="1",value="0x00007fffffffed30",type="int
*",thread-id="1",has_more="0"
(gdb)
-var-list-children var0
^done,numchild="1",children=[child={name="var0.*bar",exp="*bar",numchild="0"
,type="int",thread-id="1",has_more="0"}],has_more="0"
(gdb)
-var-evaluate-expression var0.*bar
^done,value="0"

***Value is 0

(gdb)
-exec-continue
^running
(gdb)
=thread-exited,id="1",group-id="i1"
(gdb)
*running,thread-id="all"
(gdb)
=thread-created,id="1",group-id="i1"
(gdb)
*stopped,reason="breakpoint-hit",disp="del",bkptno="2",frame={level="0",addr
="0x0000000000400530",func="main",args=[],file="test.c",fullname="/local/scr
atch/ted/tip/newfull/test.c",line="13"},thread-id="1",stopped-threads="all"
(gdb)
-var-update 1 var0
^done,changelist=[]

***No changes

(gdb)
-var-evaluate-expression var0.*bar
^done,value="10"

***Value is 10, even though we reported no changes.

The child shows an update:
(gdb)
-var-update 1 var0.*bar
^done,changelist=[{name="var0.*bar",value="10",in_scope="true",type_changed=
"false",has_more="0"}]


--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project


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