Vscode-cpptools: Hex/Binary display of debug variables in C++

[nilanjan]

OS - Linux and Mac

Hex (Octal, Binary etc.) display of variables in watch or variable window in debug is not available. This is absolutely imperative for the C++ developers.

Please provide support.

[pieandcakes]

@nilanjan I'll add it to the backlog but in the meantime you can use the gdb-mi command: -var-set-format in the debugConsole by typing -exec -var-set-format <name of variable> <format>. The difficulty we have is offering context menu options to allow the change of the format, which would require VSCode changes. You can also add the variable specifiers in the watch window to change the format.

This is the same request as #319

[nilanjan]

Does it work for lldb too?

[pieandcakes]

@nilanjan I don't have my MacBook with me but I can try it tomorrow and let you know.

[thecoder138]

Tried this on MacBook, but this does not work. Got following message.

Driver. Received command '45-exec -var-set-format hex'. It was not handled. Command 'exec' not in Command Factory (from exec -var-set-format hex)_

[nilanjan]

Any update on this? This is significantly affecting productivity. Can you point where to add this feature?

[Numinel]

How do I specify the variable name with the below command in the debug console?
-exec -var-set-format

If I use the above command while on a breakpoint (using gbg) I always get the error "msg: Variable object not found" but adding the variable name to the watch window works.

[pieandcakes]

@Numinel Are you doing this on Mac or Linux?

So the format of -var-set-format seems to be -var-set-format <NAME> <FORMAT> where name is the automatic variable name assigned by gdb/lldb.

I enabled "logging": { "engineLogging": true } and I looked for the lines where -var-create was called for Variables and the response will have the that you need to specify.

1: (918) <-1023-var-create - * "a"
1: (928) ->1023^done,name="var1",numchild="0",value="0",type="int",thread-id="1",has_more="0"

So for instance, my variable here is a and it is expecting to be "var1".

[Numinel]

I use Linux. The log show that my variable is mapped to the internal name "var29" and when using the command '-exec -var-set-format "var29" hex' the output will be shown as hexadecimal.
It was unclear to me that I had to use a different name that the variable name.

Adding a variable to the watch window with ",h" is way better though.

[nilanjan]

Is there any timeline for this feature implementation?

[pieandcakes]

@nilanjan Not at this time. If you feel like it is something you would like to contribute we welcome community support. You can find source code at: https://github.com/Microsoft/MIEngine.

[EmbeddedBacon]

This feature has been on the backlog for a while now, any plans to resurrect this feature request from the dead?

[EmbeddedBacon]

When I enabled the logging to decipher the transposed variable name the out on the Debug Console shows me the value in hex, but the Variable in the Debug tab still remains as decimal

-exec -var-set-format var158.param1 hexadecimal
1: (1205572) <-1599-var-set-format var158.param1 hexadecimal
1: (1205573) ->1599^done,format="hexadecimal",value="0xffffff01"
1: (1205573) ->(gdb)
1: (1205573) 1599: elapsed time 1
result-class: done
format: hexadecimal
value: 0xffffff01

From this particular experiment this is not a viable long term work around

[pieandcakes]

@EmbeddedBacon That is the expected behavior. If you change the var-set-format, it will change it for all future calls but existing data is not updated as the UI hasn't requested to refresh yet.

We don't have a gesture in the UI to change the value and I haven't had time to investigate if VS Code's extensibility contains the ability to add this feature.

[EmbeddedBacon]

@pieandcakes Thanks for the info, but I still couldn't get it to work. This will not work with Locals under Variables since I don't control those. I did try this in the Watch panel, but this doesn't seem to work correctly. I also noticed the translated variable is always changing. In one case the varible "pFsaCmd" was initially var39, then var40, then var42, then var43, then etc. If I didn't have pFasCmd in the Watch panel, then after trying to set its format. I tried setting the format to pFasCmd and pFasCmd.param1, but unfortunately neither worked for me. I am not sure what I am doing wrong.

Here is the output from the Debug Console. If I were to look into this, what area of the code base would I look at?

MI Log

1: (1213357) ->(gdb)
1: (1213357) 1296: elapsed time 1
1: (1213357) <-1297-var-create - * "pFsaCmd"
1: (1213363) ->1297^done,name="var39",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1213363) ->(gdb)
1: (1213363) 1297: elapsed time 5
1: (1213637) <-1298-stack-list-variables 0
1: (1213637) ->1298^done,variables=[{name="pFsaCmd"},{name="status"}]
1: (1213638) ->(gdb)
1: (1213638) 1298: elapsed time 0
1: (1213638) <-1299-var-create - * "pFsaCmd"
1: (1213643) ->1299^done,name="var40",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1213643) ->(gdb)
1: (1213643) 1299: elapsed time 4
1: (1213643) <-1300-var-create - * "status"
1: (1213644) ->1300^done,name="var41",numchild="0",value="VS_STAT_COMMAND_SUCCESS",type="VsProtocolStatusCode_t",thread-id="137",has_more="0"
1: (1213644) ->(gdb)
1: (1213644) 1300: elapsed time 1
1: (1213728) <-1301-var-list-children --simple-values "var40" 0 1000
1: (1213734) ->1301^done,numchild="5",children=[child={name="var40.task",exp="task",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var40.param1",exp="param1",numchild="0",value="4294967041",type="uint32_t",thread-id="137"},child={name="var40.param2",exp="param2",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var40.param3",exp="param3",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var40.data",exp="data",numchild="0",type="uint8_t []",thread-id="137"}],has_more="0"
1: (1213734) ->(gdb)
1: (1213735) 1301: elapsed time 6
-exec -var-set-format var40.param1 hexadecimal
1: (1242036) <-1302-var-set-format var40.param1 hexadecimal
1: (1242037) ->1302^done,format="hexadecimal",value="0xffffff01"
1: (1242037) ->(gdb)
1: (1242037) 1302: elapsed time 0

1: (1242043) <-1303-var-create - * "pFsaCmd"
1: (1242045) ->1303^done,name="var42",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1242045) ->(gdb)
1: (1242045) 1303: elapsed time 1
1: (1248577) <-1304-var-list-children --simple-values "var42" 0 1000
1: (1248584) ->1304^done,numchild="5",children=[child={name="var42.task",exp="task",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var42.param1",exp="param1",numchild="0",value="4294967041",type="uint32_t",thread-id="137"},child={name="var42.param2",exp="param2",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var42.param3",exp="param3",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var42.data",exp="data",numchild="0",type="uint8_t []",thread-id="137"}],has_more="0"
1: (1248584) ->(gdb)
1: (1248584) 1304: elapsed time 7
1: (1258554) <-1305-var-create - * "pFsaCmd"
1: (1258558) ->1305^done,name="var43",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1258558) ->(gdb)
1: (1258558) 1305: elapsed time 4
1: (1258567) <-1306-var-create - * "pFsaCmd"
1: (1258571) ->1306^done,name="var44",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1258572) ->(gdb)
1: (1258572) 1306: elapsed time 4
1: (1261053) <-1307-var-list-children --simple-values "var44" 0 1000
1: (1261060) ->1307^done,numchild="5",children=[child={name="var44.task",exp="task",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var44.param1",exp="param1",numchild="0",value="4294967041",type="uint32_t",thread-id="137"},child={name="var44.param2",exp="param2",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var44.param3",exp="param3",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var44.data",exp="data",numchild="0",type="uint8_t []",thread-id="137"}],has_more="0"
1: (1261060) ->(gdb)
1: (1261060) 1307: elapsed time 7
1: (1268111) <-1308-var-create - * "part"
1: (1268126) ->1308^error,msg="-var-create: unable to create variable object"
1: (1268126) ->(gdb)
1: (1268126) 1308: elapsed time 14
-exec -var-set-format var40 hexadecimal
1: (1390499) <-1309-var-set-format var40 hexadecimal
1: (1390500) ->1309^done,format="hexadecimal",value="0xaa57d4c"
1: (1390500) ->(gdb)
1: (1390500) 1309: elapsed time 0

1: (1402256) <-1310-var-create - * "pFsaCmd"
1: (1402260) ->1310^done,name="var46",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1402260) ->(gdb)
1: (1402260) 1310: elapsed time 4
1: (1402270) <-1311-var-create - * "pFsaCmd"
1: (1402271) ->1311^done,name="var47",numchild="5",value="0xaa57d4c <ddrMemory+18033228>",type="VsFsaOperateReq_t *",thread-id="137",has_more="0"
1: (1402271) ->(gdb)
1: (1402271) 1311: elapsed time 1
1: (1404271) <-1312-var-list-children --simple-values "var47" 0 1000
1: (1404278) ->1312^done,numchild="5",children=[child={name="var47.task",exp="task",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var47.param1",exp="param1",numchild="0",value="4294967041",type="uint32_t",thread-id="137"},child={name="var47.param2",exp="param2",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var47.param3",exp="param3",numchild="0",value="0",type="uint32_t",thread-id="137"},child={name="var47.data",exp="data",numchild="0",type="uint8_t []",thread-id="137"}],has_more="0"
1: (1404278) ->(gdb)
1: (1404278) 1312: elapsed time 7

[pieandcakes]

@EmbeddedBacon if you are trying to view just a few items as hex for gdb, you can add to the watch window as <variable>,x where x is the hex format and it should give you the value correctly.

Every time a -var-create is issued, the name assigned to it is new. When you step and a stackwalk is performed, this causes all the variables to be refreshed and in that instance the variable names are also refreshed.

As a reference, here is the documentation for variables through mi commands`. The problem is unless we have a way for the user to ask for it in the UI, we don't have a way to know to change the value. VS Code has an open issue https://github.com/Microsoft/vscode/issues/28025 which should be upvoted so they can add the gesture in the UI.

Depending if they make it a global or per variable flag, we would need to do work to let the Eval call know that we want something other than the gdb default.

[Trass3r]

For watch variables and natvis you can use format specifiers. See microsoft/MIEngine#1031.

[heartacker]

https://github.com/microsoft/vscode/issues/70377
https://code.visualstudio.com/api/references/contribution-points#contributes.menus
seem that vscode has add something to invest debugging view. it's time to pick it up

[heartacker]

https://code.visualstudio.com/updates/v1_49#_contributable-context-menu-for-variables-view
looks like delicious on 1.49.0

[heartacker]

FYI

[Trass3r]

You should link to it instead of posting a screenshot: https://github.com/microsoft/vscode/issues/28025#issuecomment-722687806