Visual C++ Team Blog

My biggest problem is not so much accuracy, but performance and scalability.  On a dual processor Opteron 256 workstation with 4 gigabytes of memory (running Windows XP 64), we are still force to disable IntelliSense, because it takes minutes for it to respond.  It is not possible to use the editor, because even the displaying of tooltips brings everything to a standstill.  SP1 for VS2005 did not fix these issues for us.  

Your tests should without doubt establish baseline performance metrics.  IntelliSense was okay in VS 2003 and even worked in VS 2005 Beta 1 for the same project we are using now, but with the final VS 2005 release I have to agree with Thomas, it just does not work.

We use VS2005 with a huge C++ project. IntelliSense for the most part works ok although I'd have to concur with the views expressed above. It can slow your machine down an awful lot whilst generating the IntelliSense (although this is better since SP1 as it now runs in the background more readily). Also it does indeed stop working after a while (sorry I can't be more specific about what triggers this). I usually end up deleting my .ncb file when this happens.

Whilst we're on the topic of IntelliSense, will Orcas have decent support for XML comment blocks in unmanaged code ? The support in C# is great, but is somewhat lacking in the old, dusty world of native C++ :)

Wow. As always with C++, any post discussing Intellisense brings up performance and accuracy issues. I'm going to clarify a couple of things on behalf of my colleague James here.

The first thing to note is that the work that James is discussing is here is targeting our infrastructure for the release *following* VS2008 (indeed, in our world , beta2 equates to being ready to start working on the next version). In this release currently dubbed Orcas+1 (how ingenious), we are planning a huge overhaul of the Intellisense & Browsing system to address once and for all the performance issues that have plagued us.

In the meantime of course, we want the experience with VS2008 to be as great as possible. To this effect, I want to respond to the specific issues you have brought up. The first thing is that our Intellisense system tries very hard to understand your code in the way that it is built. The downside is that it breaks down when it doesn't understand how code is built precisely (e.g. missing a macro definition). The simplest way to diagnose this is to generate a log file by adding /acplog:<filepath> to the advanced C++ options, which we can look at for population errors.

The second and IMHO most egregious problem is performance. Intellisense, by its very nature, "overreacts" to edits because it needs to recompute the meaning of everything that may have been affected by the edit. When modifying a header file, the effects can be pretty horrible, especially on a single-proc machine. We have improved this somewhat but not significantly (we're fixing this architecture for post VS2008 as I said though).

If some of you are willing to work with us in a tight loop, we are currently profiling our existing Intellisense functionality for any possible performance gains. Please contact me directly at borisj@microsoft.com so I can include you this process.

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Boris Jabes

Visual C++ PM

For me the problem isn't speed, or failures when the code isn't well defined, but failures when the code is properly written.

Sometimes I'll write a line of code where Intellisense works, then press enter to write a  new line starting with the exact same object and find that Intellisense doesn't have any info to give me, despite the previous line working perfectly and being well-formed code!

Equally mystifying is Intellisense's complete lack of ability to work on certain areas of the codebase - it just seems unable to parse entire subsystems, meaning you can't use it at all when dealing with certain classes.

Andrew, could you try setting up the logging I mentioned and we can investigate your specific failures? Often, it's the case that we don't grok all the source due to incomplete macro context.

Thanks,

Boris

Sometimes deleting the .ncb file and letting it rebuild does help for a while, sometimes it doesn't.  I can put the mouse cursor on an identifier, right-click and choose either "go to declaration"[*] or "go to definition"[*] and it says there's no declaration or definition.  Still compiles OK.

I can right-click and choose "go to definition"[*] and it goes to the declaration in a .h file which isn't the definition in a .cpp file.  Have to find the .cpp file myself and find the definition myself.  If the definition is a function body then sometimes the combo boxes above the code can be used in jumping to the function definition, sometimes not.

I can right-click and select "browse all references to this identifier"[*] and the resulting list will be empty, no references at all, not even the instance that I just clicked on.

[* If any of these approximate quotes is too obscure to be recognized, please say, and I'll post what it actually says in Japanese.]

I am experiencing the problems listed by the above posts.  As Bubu suggested, it would be nice to make Intellisense manually updatable.  Enabling “Manual Rebuild” mode (Somewhere buried in the VS settings screen), would also prevent Intellisense from "going nuts" and rebuilding itself when you trying to do something else (like type).

Then when you go for a coffee break, you could press the "Rebuild Intellisense" button (aka. the "Hammer My Computer" button.)

Maybe a related useful feature would be a semi-manual mode where Intellisense is rebuilt at the end of a compilation.  I know you guys would like to keep Intellisense always updated (and independent of compilation), but this automatic rebuilding does not seem to work out unless you have new + powerful workstation.

VS2005 SP1 has slightly improved Intellisense Rebuilding performance, but it's not enough.

On a good recent machine, working on huge code size, intellisense can still hangs VC8 for 20 secs if you do a right click and "jump to definition".

That's simply not acceptable.

Boris,

We are a C++ house and are on a mix of VS 6.0, 2003 and 2005. Until now, I have been holding off on upgrading everyone, and every project, until VS 2008 comes out.

However, this was predicated on Intellisense not sucking.

On July 10, you stated that intellisense will not be fixed until "Orcas+1". I am seriously pissed off about this news. I have suffered with the shitty C++ support in VS2005 since it was in beta, and a big reason is the extremely crappy intellisense support. To push this off is to stab your loyal customers in the back while spitting in their faces. It is simply unnacceptable.

Since upgrade pain is costly and serious, with this news I am on the verge of cancelling the planned purchase of VS 2008 entirely.

(I don't blame you, I blame the idiot product managers and executive staff. I used to be a major Microsoft booster and apologist. In the last two years, the assholes in charge of Microsoft have almost completely alienated me and other loyal Microsoft customers. Too bad Borland/CodeGear is so messed up that they are unable to make a competitive product.

Please forward this to the boneheads in charge and tell them to get their collective heads out of their asses.)

When we are working with Visual Studio IDE, sometimes we encounter issues related to intellisense. The