If an application†crashes,
I hit "Debug" and Visual Studio is my currently registered Just-In-Time (JIT) debugger:
Visual Studio appears, but there's no way to debug anything:
I do not see any disassembly
I do not see any registers (assuming it runs on a CPU with registers)
The call stack is empty (assuming the CPU has a stack pointer)
I do not see any symbols (assuming it had any)
I do not see reconstructed source code from reflection (assuming it was managed)
Other JIT debugger products are able to show disassembly, but they are either command-line based (Debugging Tools for Windows), or do not support symbols (OllyDbg, Delphi). Additionally, my question is about debugging using Visual Studio, since I already have it installed, and it is already my registered JIT.
How do you debug a program using Visual Studio?
Alternatively: has anyone written a graphical debugger that supports the Microsoft symbol server?
†Not, necessarily, written in Visual Studio.
Edit: Changes title to process rather than application, since the latter somehow implies "my application."
Edit: Assume the original application was written in assembly language by Steve Gibson. That is, there is no source code or debug information. Visual Studio should still be able to show me an assembly dump.
Looking at the screenshot it appears that Visual Studio is currently debugging in Run mode - you need to break execution of the process before it makes sense to look at things like the call stack, etc...
To break execution of the process you either need to hit a breakpoint, or you can break execution of the process at any time by using the Pause / Break all toolbar item (Control + Alt + Break).
Then you should be able to access the following windows under the Debug -> Windows menu:
The disassembly window
The registers window
The call stack window
The modules window shows a list of loaded modules along with where their corresponding symbols are loaded from (if loaded)
Some other useful windows:
The processes window is useful if you are debugging more than one process at a time
The Threads window
The Memory window (there are four of them)
The Locals window
Some of these might not be visible by default depending on which window configuration you selected when you first started Visual Studio - if you can't find them then right click on the toolbar and goto customise to add them.
Visual studio doesn't reconstruct soucre code from disassembly - you really need to have the original source code available to you, otherwise the symbols almost certainly won't match the source code you are debugging.
If you are debugging unmanaged modules without source code then I recommend you at least try WinDbg - its user interface is a bit clunky at times, and it does have a steep learning curve, however it is a very powerful debugger supporting many features that Visual Studio doesn't - it may be more suited to the sort of debugging you need to do.
(Visual Studio is a fantastic debugger, however it's primarily used to debug modules where the source code is available and so it lacks certain features in favour of a better user experience).
Assuming this is your application that you wrote in VS, just press F5 to run the program and either use a breakpoint, or manually break the program to start debugging.
The problem in the last screenshot is that Visual Studio did not enter break mode automatically. That seems like a bug. If you hit the 'pause' button on the toolbar, it would enter break mode, giving you disassembly, and a callstack.
According to that last screenshot you were actually attached to the program ... the output windows shows it loaded stripped symbols for OLE and the crt.
You can debug a program with Visual Studio if you have the debug information available for this program. It's the difference between compiling a Release version (normally without debug information) and compiling a Debug version.
This dialog to debug a program is handy if you are testing the debug version of your self-written program. You can attach it "on-the-fly" to your Visual Studio debugger and look for the problem.
If it is not your program or it is your program, but does not provide debugging information which Visual Studio can understand, then you are out of luck.
Use menu Debug -> Windows -> Disassembly (I think the keyboard shortcut is Alt + 8, but I am configured for VC 6.0 bindings, because that's how I roll, and it may have changed).
You can get public symbols for the operating system from http://msdl.microsoft.com/download/symbols. Add it to the list in menu Tools -> Options -> Debugging -> Symbols -> Symbol file locations.
Also, make sure you are running in the same integrity level as the application. Or always run Visual Studio as Administrator.
I guess you are already in the Debug mode. The "Run" button is disabled. Just go to Debug -> windows -> Disassembly to view disassembly.
Related
I have recently bought new laptop:Hp specter x360 i7-6500 with 8gb RAM.
I have installed Visual Studios 2015 Community in an offline mode, later I updated it.I am currently working in c# window forms.
The point is when I press the button 'Start Debugging', VS build the program in normal speed, but it takes like 10-15 sec to show the output, even for the small programs. This whole thing is for first time debugging after code editing, if I close it and run it again without changing the code, it shows the output on the spot.
And if I run the same program in my old laptop, which has lower specs and same VS, that laptop show the result much quicker.
Based on your screenshot, I see that VS tries to download PDB symbols for system assemblies, which are used by your application. Loading the debug symbols provides simplify debugging of an application but it also slows down the application loading.
You can change symbols loading settings, in the Tools-Options-Debugging-Symbols menu of Visual Studio. Here you can disable symbol loading (if you would use this option you need to load symbols manually using the Debugging-Windows-Modules interface). Or exclude system modules which usually are not necessary to debug a common application.
Check this blog post which provides a great description about how VS uses debug symbols.
I'm trying to debug a native C++ application and need to see the memory alignment in structures.
I wanted to use the debugging window "Memory", but I can't find it where it should be.
As stated here I enabled "address-level debugging", but it's still not there.
I'm using the Ultimate Edition, so this shouldn't be the problem!
You can only use the memory window while the debugger is running.
So instead of clicking "Run" try clicking "Step into", or make a breakpoint somewhere so the debugger doesn't terminate automatically. Then look under Debug -> Windows -> Memory.
I see that with the 'Attach to Process', one can debug the process by setting up break point in Visual Studio IDE.
I think it's pretty cool, and I'm curious what's the mechanism that enables it. I also found that gdb and Mac's Xcode supports the technology.
Q1 : Can anyone explain how does this work? How can the process mapped to a breakpoint in an IDE or gdb environment?
Q2 : Are there other compiler/debugger options than /Zi or -g (adding debug info)?
Q3 : Is this the way to debug dll (dynamic library)?
ADDED
I found this one with MSDN - http://msdn.microsoft.com/en-us/library/c6wf8e4z.aspx
The most common scenario I know of is using a browser to debug web code. In these cases, you start Visual Studio in debug mode and then attach to the browser and call the page in question. When the page is called it starts running the code in the debugger. Essentially, the debugger watches the process and when it hits code in VS, it starts debugging.
The same is true with other applications that are calling code you are running in Visual Studio. When you cross the boundary to the code, the debugger catches the call and starts running code in VS.
I use it fairly frequently when developing plugins for existing applications (Maya, Reaper, etc). As a general rule, plugins can't be run independently, so in order to debug them I have to run the host program and use "Attach to Process" to run the debugger on my plugin, at which point I can set breakpoints and all that other debugging goodness. You need to have debugging symbols and al that for the plugin, but you don't need to have them for the host application.
I am using Visual Studio 2008. I don't need to debug some DLLs in my project, so can I disable symbol loading when debugging a Visual C++ program? Does it help to make startup time faster when debugging?
The symbols are all local, so I don't have those slow loading problem, just want to make debugging faster and faster.
For example I am using Qt libraries, when I hit "Starting Debugging", the Output window shows that the symbols for Qt libraries are loaded. If VS can stop loading those symbols, the debugging startup time should be faster. Of course, I still want VS to load symbol for my executable.
Just found out that Visual Studio 2010 actually do what I want.
To load only the symbol for your executable file, without loading other symbols (eg: DLLs):
Go to Tools->Options->Debugging->Symbols
Click "Only specified modules"
Clear "Always load symbols located next to modules"
Click "Specify modules"
Click the new icon
Enter your executable filename (eg: my-awesome-app.exe)
Also found out that Visual Studio 2010 seems to perform better than Visual Studio 2008 when debugging. At least the IDE layout switches back faster when the debugging is stopped.
I am not sure what you mean by 'startup'. I assume you are talking about the launching of the actual application. The time to launch the target application is expensive regardless of mode you launch it. It may be less in Release but that will be negligible.
Turning off all symbol paths as mentioned in the other solution is a viable option. However, I am not sure why you are debugging if you do not want symbols for your launched application. Without the applications symbols you will not be able to see where you are in the source code when you are debugging.
If you are looking for a faster debugging experience you can use WinDbg. It comes with the Windows SDK but can also be downloaded seperately. If is a faster UI than Visual Studio, but it is much more cumbersome to use if you are more comfortable with a GUI. WinDbg uses commands to perform almost all tasks, but you can do some great debugging and it is faster in many cases compared to Visual Studio. In the event you want to debug C++\CLI or any managed application (e.g. C#), I would stick with Visual Studio. There is an extension in WinDbg called SOS, but it requires some advanced debugging experience to use correctly.
My C# code is calling an unmanaged third-party library function via P/Invoke, and the unmanaged function is having some strange side effects. I want to debug into it and see what it's doing.
If I debug my C# code, and try to "Step Into" the P/Invoke call, it steps over instead. No surprise there -- I expected that; it doesn't have the source for this DLL, and I didn't tell it I was okay with seeing the disassembly view.
So I switch the debugger to disassembly view (Debug > Windows > Disassembly). Now I see the individual x86 instructions in my JITted code. Again I try to step into the P/Invoke call. Again, it steps over instead -- even though I clearly told it to Step Into an x86 CALL instruction. How hard is it to step into an x86 CALL?
My Googling thus far has shown me a couple of options that can affect this, and I've already set them:
In Tools > Options > Debugging > General, "Enable Just My Code" is unchecked.
In Project > Properties > Debug tab, "Enable unmanaged code debugging" is checked.
No good. Visual Studio still refuses to step in.
I don't have a PDB for the third-party DLL, but that shouldn't matter. I don't care about source code or symbol information. (Well, actually they'd be really nice, but I already know I'm not going to get them.) Visual Studio can do x86 debugging (that's what the Disassembly view is for), and all I want to do is step into the x86 code.
What else do I need to do to get VS to allow me to step into the x86 instructions inside a P/Invoke call?
This may help you solve the problem:
(by Graviton)
CallingConvention = CallingConvention.Cdecl
Also this mentions that you need to detach managed debugger and re-attach unmanaged when crossing the boundaries. You might need to check the capabilities of mixed debugger and it's preferences from MSDN.
And finally, using Ed Dore' answer:
Under Tools.Options dialog, select the
Debugging category, and make sure the
"Enable Just My Code" setting is
unchecked. From the Project
properties, select the Debug tab, and
then ensure that "Enable unmanaged
code debugging" is checked.
Once you've got these squared away,
you should get the mixed mode
debugging support working.
Also, if you use "Debug.Attach To
Process" , be sure to hit the
"Select..." button in the "Attach To
Process" dialog, and select both
Managed and Native debugging support.
One thing I would try is going from C# to C++/CLI code, and then from C++ to the third-party code. Once you're in C++ (and free of the P/Invoke infrastructure), you might have better luck with the disassembly view.
In your C# project properties, in the Debug tab, check Enable native code debugging. Worked for me in VS 2012.
Credit goes to billb.
Also, since it's a third party library, ensure Enable Just My Code is unchecked in Options > Debugging.
I had a similar issue where I was debugging a C# exe that called my own C++ dll via PInvoke, all part of the same solution. Enabling native code debugging in my c# project allowed me to debug my C++ code.
Had same issue today.
What helped in my case was to run Visual Studio as administrator.
My setup:
Visual Studio 2019
Windows 10