Hi Vladimir,
Dragonegg does not work with -flto. It generates assembler code on which gas complaints (a lot of non-assembler code like target data-layout which are not in comments).
actually it does work with -flto, in an awkward way. When you use -flto it spits out LLVM IR. You need to use -S, otherwise the system assembler tries (and fails) to compile this. You need to then use llvm-as to turn this into LLVM bitcode. You can then link and optimize the bitcode either by hand (using llvm-ld) or using the gold plugin, as described in http://llvm.org/docs/GoldPlugin.html It is annoying that gcc insists on running the system assembler when passed -c. Not running the assembler isn't only good for avoiding the -S + llvm-as rigmarole mentioned above. LLVM is now capable of writing out object files directly, i.e. without having to pass via an assembler at all. It would be neat if I could have the plugin immediately write out the final object file if -c is passed. I didn't work out how to do this yet. It probably requires some gcc modifications, so maybe something can be done for gcc-4.6. For transparent LTO another possibility is to encode LLVM bitcode in the assembler in the same way as gcc does for gimple when passed -flto. I didn't investigate this yet. Ciao, Duncan.
