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
llvm-svn: 173281
Previously we would serialize the macro redefinitions as a list, part of
the identifier, and try to chain them together across modules individually
without having the info that they were already chained at definition time.
Change this by serializing the macro redefinition chain and then try
to synthesize the chain parts across modules. This allows us to correctly
pinpoint when 2 different definitions are ambiguous because they came from
unrelated modules.
Fixes bogus "ambiguous expansion of macro" warning when a macro in a PCH
is redefined without undef'ing it first.
rdar://13016031
llvm-svn: 172620
Argyrios Kyrtzidis