Restricting Valgrind to a specific function - valgrind

I have a big program to run. Using valgrind it takes hours and hours to run. I heard that there is something where we can call valgrind for a specific function in the program. And rest of program will be executed normally(without valgrind env).
Can anybody help me with this. I tried searching it over internet , May be I am missing the term to search.

It all depends on what tool you're wanting to use. For callgrind (the profiler in valgrind) there is an option --toggle-collect=function to allow you to collect information inside a particular function and all its children.
However if the tool you're interested in is memcheck (for capturing leaks / memory errors) then there is no available command line option.

Googling "valgrind profile specific function only" and go "I feel lucky"
In addition to enabling instrumentation, you must also enable event collection for the parts
of your program you are interested in. By default, event collection is enabled everywhere.
You can limit collection to a specific function by using --toggle-collect=function. This will
toggle the collection state on entering and leaving the specified functions. When this option
is in effect, the default collection state at program start is "off". Only events happening
while running inside of the given function will be collected. Recursive calls of the given
function do not trigger any action.
More here

Related

How to build a call graph for a function module?

A while ago during documenting legacy code I found out there is a tool for displaying call graph (call stack) of any standard program. Absurdly I wasn't aware of this tool for years :D
It gives fancy list/hierarchy of calls of the program, though it is not a call graph in a full sense, it is very helpful in some cases.
The problem is this tool is linked only to SE93 so it can be used only for transactions.
I tried to search but didn't find any similar tool for reports or function modules. Yes, I can create a tcode for report, but for function module this approach doesn't work.
If I put FM call inside report and build a graph using this tool, it wraps this call as a single unit and does not analyze deeper. And that's it
Anybody knows a workaround how we can build graph for smth besides transaction?
The cynic in me thinks RS_CALL_HIERARCHY was left to rot. Sandra is right, it definitely used to work. Once OO came to abap, interfaces and dynamic/generic code became possible. So a call heirarchy based on static code analysis was pushing proverbial up hill.
IMO the best way to solve this is a FULL trace and then to extract the data from the trace.
There are even external tool that do that.
This is of course, still limited as running a trace on every execution path can be very time consuming. Did I hear someone say small Classes please ?
Trans SAT.
Make sure teh profile you use isnt aggregating, and measure the blocks you are interested.
Now wade you way through the trace.
https://help.sap.com/doc/saphelp_ewm93/9.3/en-US/4e/c3e66b6e391014adc9fffe4e204223/content.htm?no_cache=true
Have fun :)
The call hierarchy displays also works for programs and function modules.
In my S/4HANA system, for VA01, it displays:
Clicking the hierarchy of function module CJWI_INIT displays:
I get exactly the same result by calling the function module RS_CALL_HIERARCHY this way:
The parameter OBJECT_TYPE may have these values:
P : program
FF : function module
The "call graph" is not maintained anymore since at least Basis 4.6, and it doesn't work for classes and methods.
But the tool is buggy: in some cases, a function module containing a PERFORM at the first line, it may not be displayed, whatever the call graph is launched from SE93 or directly from RS_CALL_HIERARCHY.

Scripting Language with "edit and continue" or "hot swap" support? ( Maybe possible in Lua?)

I am making my existing .Net Application Scriptable for non programming users. I added lua, it works like a charm. Then I added debug functionality(pause/continue/step) via debug.sethook. It works also like a charm.
Now I realize that my Application needs edit and continue feature like Visual Studio has it. You pause the execution can edit the code and then continue from your current state with changes applied. This feature is very important to me. I thought this would be easy to do for scripting languages.
Everywhere I read that scripting languages can do this. But even after spending hours of searching I haven't found an Lua implementation yet. It hasn't to be Lua but hot swapping code in Lua would be my first choice.
How can the ability for the user be offered to pause and edit the script and than continue the execution with changes applied?
NOTE: It doesn't have to be Lua every scripting language would be okay
Update
#Schollii
Here is an example:
function doOnX()
if getValue() == "200" then
value = getCalculation()
doSomething() -- many function calls, each can take about 2s
doSomething()
doSomething()
print(value)
doX(value)
end
end
doOnX()
Thank you for your suggestions. This is how it might work:
I will use https://github.com/frabert/NetLua Its a very cool, well written 100% C# Lua Interpreter. It is generating an AST tree first and then directly executing it.
The parser needs to be modified. In Parser.cs public Ast.Block ParseString(string Chunk) there is a parseTree generated first. parseTree.tokens[i].locations are containing the exact position of each token. The Irony.Parsing.ParseTree is then parsed again and is converted to a NetLua.Ast.Block but the location information is missed. I will need to change that so later I will know which Statement is in which line.
Now each Statement from the AST tree is directly executed via EvalBlock. Debug functionality (like I have in my C Binding lua Interpreter DynamicLua via debug.setHook) needs to be added. This can be done in LuaInterpreter.cs internal static LuaArguments EvalBlock(`. Pause/continue/step functions should be no problem. I also can now add current line Highlighting because each statement contains position line information.
When the execution is paused and the code was edited the current LuaContxct is saved. It contains all variables. Also the last Statement with the last execution line is saved.
Now the code String is parsed again to a new AST tree. It gets executed. But all statements are skipped until the saved statement with the line statement is reached. The saved LuaContext is restored and execution can continue with all changes applied.
New variables could be also added after the last executed line, because a new NetLua.Ast.Assignment Statement could just add a new variable to the current LuaContext and everything should just work fine.
Will this work?
I think this is quite challenging and triicky to do right.
Probably the only way you could do that is if you recompile the chunk of code completely. In a function this would mean the whole function regardless of where edit is in function. Then call the function again. Clearly the function must be re-entrant else its side effects (like having incremented a global or upvalue) would have to be undone which isn't possible. If it is not reentrant it will still work just not give expected results (for example if the function increments a global variable by 1 calling it again will result in the global variable having been increased by 2 once the function finally returns).
But finding the lines in the script where the chunknstarts and ends would be tricky if truly generic solution. For specific solution you would have to post specific examples of scripts you want to run and examples of lines you would want to edit. If the whole user script gets recompiled and rerun then this is not a problem, but the side effects is still an issue, examples could help there too.

'Watcher' program for messageboxes

I am trying to brainstorm how to go about creating a program that will be actively running alongside my application and will watch for messageboxes to be shown in the application and take all the information(text, buttons, parameters) included with that messagebox and house them as an object in a global variable available throughout my application.
Is there anyway to tell programatically in my application that a messagebox is about to appear and to take any information related to it and place it in an object? Aside from having to scan the code, which isn't what I'm looking for especially since there's many places messageboxes will appear, this would give incorrect information.
Or is there a better way to go about this? All I'm looking for is information associated with the messagebox that is about to appear(and not show the messagebox then)
Any tips or websites I could reference is greatly appreciated!!!
Create your own class that takes in the same parameters as the standard messagebox.show and then calls the messagebox.show passing the parameters on. When you are ready, you can then put some code before the standard call that will capture the information.
I always create my own messagebox.show so I can control it. It's nice to have a standard title and there maybe time that you need to do special stuff with it, like log the messages.
BTW, because of scoping, if your class is in the same project, yours will be used instead of the standard, unless you fully qualified it: system.windows.forms.messagebox.show().

Stepping through code in Google Apps Script (equivalent VBA-GAS )

When writing my VBA macros I often used "F8" so as to debug the macro line by line. Is there a similar feature in Google Apps Script?
Similar, but not the same.
Google Apps Script is developed in a dedicated IDE1 called the Script Editor, which provides support for single-step execution and breakpoints, among other things.
For a quick introduction to debugging using the IDE, see this video. The Troubleshooting section of the online documentation includes a quick overview of the basics.
Debugging Functions with parameters
In the IDE you can select any function in your script for execution, and then select the "run" or "Debug" icons to start. Unfortunately, there is no way to pass parameters to a function this way, so here are a few ways you can deal with that.
Set defaults. There are numerous ways to define defaults in javascript, here is a picture of the debugger operating on a function using the simplest of them. The function toText() from this answer accepts a number as a parameter, so for this example we are forcing the default value to 21. The picture shows the debugger paused at line 40; if we continue stepping through the function we expect to end up with a result s == 'Twenty-one'.
Write a test function. This is a better approach than setting defaults, because it allows you to write multiple test cases, and it avoids polluting your target function with debug code. As an example, the target function flipFlopAndFly() and its test function test_flipFlopAndFly() were provided in this answer. The test function accesses the spreadsheet to provide appropriate data for testing the target, so we can easily modify the data for different tests. Note also, this function includes error checking, so it would not be appropriate to test by forcing default values.
There are many variations on these basic patterns, so feel free to adapt them to your own situation. It will help your debugging capability to think while you are writing about how you would step through your code:
Is each important object and value stored in a var, so you can see it?
Is your function result (return value) in a var?
Custom Functions
When developing or debugging custom functions that will be called from a spreadsheet, remember that you cannot "jump" into the IDE. If you need to step through the script, you will need to work entirely within the IDE to observe execution of your code. You can use the techniques described above to debug custom functions.
1 Integrated Development Environment

Track all ObjC method calls?

Sometimes when looking at someone else's large Objective-C program, it is hard to know where to begin.
In such situations, I think it would be helpful to log every call to every non-Apple method.
Is there a way to do that? Basically, make one change in some central place, and log every method that is called. Preferably limited to non-Apple methods.
You can set the environment variable NSObjCMessageLoggingEnabled to YES. This will write a log of all message sends in the folder /tmp/msgSends-xxx.
You could add a symbolic breakpoint to objc_msgSend(), and have it log the second parameter without stopping.
How to do it for your own methods only though is a toucher task. Maybe if you could inspect the class name being called and do some magic to have a conditional breakpoint for only calls where the class' prefix matches your own?
I don't think logging every single call is practical enough to be useful, but here's a suggestion in that direction.
On a side note, if it's a large program, it better have some kind of documentation or an intro comment for people to get started with the code.
In any case, every Cocoa application has an applicationDidFinishLaunching... method. It's a good place to start from. Some apps also have their principal (or 'main window') class defined in the Info.plist file. Both these things might give you a hint as to what classes (specifically, view controllers) are the most prominent ones and what methods are likely to have long stack-traces while the program is running. Like a game-loop in a game engine, or some other frequently called method. By placing a breakpoint inside such a method and looking at the stack-trace in the debugger, you can get a general idea of what's going on.
If it's a UI-heavy app, looking at its NIB files and classes used in them may also help identify parts of app's functionality you might be looking for.
Another option is to fire up the Time Profiler instrument and check both Hide missing symbols and Hide system libraries checkboxes. This will give you not only a bird's eye view on the methods being called inside the program, but also will pin-point the most often called ones.
By interacting with your program with the Time Profiler recording on, you could also identify different parts of the program's functionality and correlate them with your actions pretty easily.
Instruments allows you to build your own "instruments", which are really just DTrace scripts in disguise. Use the menu option Instrument >> Build New Instrument and select options like which library you'd like to trace, what you'd like to record when you hit particular functions, etc. Go wild!
That's an interesting question. The answer would be more interesting if the solution supported multiple execution threads and there were some sort of call timeline that could report the activity over time (maybe especially with user events plotted in somehow).
I usually fire up the debugger, set a breakpoint at the main entry point (e.g. - applicationDidFinishLaunching:withOptions:) and walk it in the debugger.
On OSX, there are also some command-line tools (e.g. sample and heap) that can provide some insight.
It seems like some kind of integration with instruments could be really cool, but I am not aware of something that does exactly what you're wanting (and I want it now too after thinking about it).
If one were to log a thread number, and call address, and some frame details, it seems like the pieces would be there to plot the call timeline. The logic for figuring out the appropriate library (Apple-provided or third party) should exist in Apple's symbolicatecrash script.