- We actually pretend that we have two separate types for LLVM assembly/bitcode because we need to use the standard suffixes with LTO ('clang -O4 -c t.c' should generate 't.o').
It is now possible to do something like:
$ clang -emit-llvm -S t.c -o t.ll ... assorted other compile flags ...
$ clang -c t.ll -o t.o ... assorted other compile flags ...
and expect that the output will be almost* identical to:
$ clang -c t.c -o t.o ... assorted other compile flags ...
because all the target settings (default CPU, target features, etc.) will all be initialized properly by the driver/frontend.
*: This isn't perfect yet, because in practice we will end up running the optimization passes twice. It's possible to get something equivalent out with a well placed -mllvm -disable-llvm-optzns, but I'm still thinking about the cleanest way to solve this problem more generally.
llvm-svn: 105584
- -emit-llvm no longer changes what compilation steps are done.
- -emit-llvm and -emit-llvm -S write output files with .o and .s
suffixes, respectively.
- <rdar://problem/6714125> clang-driver should support -O4 and -flto,
like llvm-gcc
llvm-svn: 67645
Daniel Dunbar