Add a proper algorithm to compute accurate source ranges for diagnostics with
caret locations and source ranges in macros.  Makes ranges more accurate
in some cases, and fixes an assertion failure.

Fixes <rdar://problem/12472249>.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167353 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed