Any posibility to modify the sub and function bodies created via VBA IDE - excel

Question

I am willing to add some code to the begining and end of each sub or function for enabling flow tracing / debugging.
Now I copy this (almost standard code manually into the beginig of each sub / function, and also before each exit sub/function and end sub / function statement.
Something like this
public sub a()
...
**logging_successful = pushCallIntoStack("sub a")**
...
On Error Goto errorOccured
...
**logging_successful = popCallFromStack("sub a")**
Exit Sub
...
errorOccured:
...
**logging_successful = popCallFromStack("sub a")**
...
End Sub
Being able to insert these standart codes via VBIDE as default - at least in the standard entry and exit points - will save me sometime.

Answer 1

What you want to do is technically doable but are you sure you want to add boilerplate code with hard-coded strings to all of your procedures? That is lot of maintenance which also makes it much harder to refactor your code. I've seen lot of error messages saying it came from "Foo" but they came from "Bar" because at one point the code was in Foo but then it got moved or renamed to Bar, but they forgot to update the string constant. There is no such guarantees that the string constants are in sync with the actual procedure names.
Before sinking potentially hours into this solution, I would encourage you to first consider third-party addins that can do a much better job of helping you getting the detailed error output you need. One such solution would be vbWatchDog which provides you not only the stack tracing but also much extended diagnostics... without any changes to your source code. Precisely because it can do without any embedding constants, it won't be liable to give you outdated information.
I should note that there are also other third-party addin such as MZ-Tools which provides a one click button for adding an error template that could conceivably be used to provide what you want. However, the operation is not reversible, which adds to your maintenance burden; changing a procedure would mean you'd have to strip away the old error template, then re-add, and if there's any customization, to re-add it.
If in spite of all, you insist on continuing doing it by your own hand, you can do something like the following:
Public Sub AddBoilerPlate(TargetComponent As VBIDE.VBComponent)
Dim m As VBIDE.CodeModule
Dim i As Long
Set m = TargetComponent.CodeModule
For i = m.CountOfDeclarationLines + 1 To m.CountOfLines
Dim ProcName As String
Dim ProcKind As VBIDE.vbext_ProcKind
ProcName = m.ProcOfLine(i, ProcKind)
Dim s As Long
s = m.ProcBodyLine(ProcName, ProcKind) + 1
m.InsertLines s, <your push code>
'Loop the lines within the procedure to find the End *** line then insert the pop code
Next
End Sub
This is an incomplete sample, does not perform checks for pre-existing template. A more complete sample would probably delete any previous template before inserting.

Answer 2

You may need to amend the codes for your own needs but below's the general idea (e.g. change "Module2" to the name of your module and include more checks to determine where to add in new codes)
Public Sub sub_test()
Dim i As Long
With ThisWorkbook.VBProject.VBComponents("Module2").CodeModule
For i = 1 To .Countoflines
If InStr(.Lines(i, 1), "End Sub") > 0 Then
.Insertlines i, "**logging_successful = popCallFromStack(""sub a"")**"
End If
Next i
End With
End Sub