[PATCH] Analyzer: Refactor callstring to work with pairs of supernodes.

[Ankur Saini via Gcc-patches]

The patch generalises how analyzer's call_string tracks function calls, 
including the calls that doesn’t have an underlying call graph edge, making it 
possible to work with function calls which are not discovered by GCC's middle 
end.

Successfully bootstrapped and completed regress tests on x86_64-linux-gnu.

call_string.patch
Description: Binary data

Thanks 
- Ankur