[cfe-commits] please review: adding module-level metadata for ThreadSanitizer

[Eric Christopher]

On Aug 22, 2012, at 12:20 AM, Kostya Serebryany <kcc at google.com> wrote:

> Hello, 
> 
> I'd like to resurrect an old discussion: how to selectively disable ThreadSanitizer (or AddressSanitizer, etc) instrumentation 
> for particular functions. 
> For AddressSanitizer we currently use a function attribute "AddressSafety" (if it is not set, instrumentation does not happen), 
> but Chris doesn't like this idea (attributes are a scarce resource) and he suggested to use module-level metadata instead of an attribute. 
> 
> The attached clang patch adds such metadata node for all functions when -fthread-sanitizer is given. 
> If that is what we want, I'll gradually change AddressSanitizer to use similar approach and will kill the "AddressSafety" attribute.
> 
> BTW, the code looks like this:
>   llvm::Value *Fn[] = { F }; ...
>   llvm::MDNode::get(VMContext, Fn);
> Do we want this code to look like 
>   llvm::MDNode::get(VMContext, F);  
> (i.e. to add more llvm::MDNode::get() methods)?

Bill has been working on something similar for command line options and LTO. There's still been some chatting about it, but Bill's planning on updating the list in the next few days with what's going on if waiting a bit is ok?

-eric