Question

I would want to compile existing software into presentation that can later be run on different architectures (and OS).

For that I need a (byte)code that can be easily run/emulated on another arch/OS (LLVM IR? Some RISC assemby?)

Some random ideas:

• Compiling into JVM bytecode and running with java. Too restricting? C-compilers available?
• MS CIL. C-Compilers available?
• LLVM? Can Intermediate representation be run later?
• Compiling into RISC arch such as MMIX. What about system calls?

Then there is the system call mapping thing, but e.g. BSD have system call translation layers.

Are there any already working systems that compile C/C++ into something that can later be run with an interpreter on another architecture?

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Edit

Could I compile existing unix software into not-so-lowlevel binary, which could be “emulated” more easily than running full x86 emulator? Something more like JVM than XEN HVM.

Answer 1

There are several C to JVM compilers listed on Wikipedia’s JVM page. I’ve never tried any of them, but they sound like an interesting exercise to build.

Because of its close association with the Java language, the JVM performs the strict runtime checks mandated by the Java specification. That requires C to bytecode compilers to provide their own “lax machine abstraction”, for instance producing compiled code that uses a Java array to represent main memory (so pointers can be compiled to integers), and linking the C library to a centralized Java class that emulates system calls. Most or all of the compilers listed below use a similar approach.