[LLVMdev] Source code annotations on loops

[Trevor Harmon]

Hi,

I'm writing an analysis pass that needs to know an upper bound on all  
loops. LLVM can determine loop bounds in some situations  
(Loop::getTripCount), but in other cases the developer of the analyzed  
code will need to supply them. One way this is accomplished is with  
commented annotations like:

// @loopBound=10
while (i < j) { ... }

I could use LLVM's debug info metadata to locate the source file and  
line number associated with this loop, then read the file and extract  
the comment, but I'm wondering if there's a better, more structured  
way. For example, there's the standard __attribute__ annotation  
facility in C:

http://clang-analyzer.llvm.org/annotations.html

But it can only annotate functions, not loops.

Is there another approach? Thanks,

Trevor