Previously, we would clone the current diagnostic consumer to produce
a new diagnostic consumer to use when building a module. The problem
here is that we end up losing diagnostics for important diagnostic
consumers, such as serialized diagnostics (where we'd end up with two
diagnostic consumers writing the same output file). With forwarding,
the diagnostics from all of the different modules being built get
forwarded to the one serialized-diagnostic consumer and are emitted in
a sane way.
Fixes <rdar://problem/13663996>.
llvm-svn: 181067
building module 'Foo' imported from..." notes (the same we we provide
"In file included from..." notes) in the diagnostic, so that we know
how this module got included in the first place. This is part of
<rdar://problem/12696425>.
llvm-svn: 169021
modules. This leaves us without an explicit syntax for importing
modules in C/C++, because such a syntax needs to be discussed
first. In Objective-C/Objective-C++, the @import syntax is used to
import modules.
Note that, under -fmodules, C/C++ programs can import modules via the
#include mechanism when a module map is in place for that header. This
allows us to work with modules in C/C++ without committing to a syntax.
llvm-svn: 147467
Douglas Gregor