Documentation: add a note that -cc1 options are not guaranteed to be stable


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173280 91177308-0d34-0410-b5e6-96231b3b80d8
[PCH] Temporarily disable the "ambiguous macro" warning that is currently bogus with a PCH
that redefined a macro without undef'ing it first.

Proper reconstruction of the macro info history from modules will properly fix this in subsequent commits.

rdar://13016031

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173281 91177308-0d34-0410-b5e6-96231b3b80d8
docs: clear up ambiguity

Anybody using clang is a "developer".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173282 91177308-0d34-0410-b5e6-96231b3b80d8
Factor the trait for lookup into the on-based hash table of
identifiers into two parts: the part that involves dealing with the
key (which can be re-used) and the ASTReader-specific part that
creates the IdentifierInfos. While I'm at it, StringRef'ify this code,
which was using pair<const char*, unsigned>. No functionality change.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173283 91177308-0d34-0410-b5e6-96231b3b80d8