C++ frontend only compiler (convert C++ to C).

Question

I'm currently managing some C++ code that runs on multiple platforms from a single source tree (Win32, Linux, Verifone CC terminals, MBED and even the Nintendo GBA/DS). However I need to build an app targetted at an embedded platform for which there is no C++ compiler (C only). I remmber that many of the early C++ compilers were only front-ends stitting on existing C compilers (Glockenspiel for example used MSC). Are there any such 'frontend' C++ compilers in use today that will generate C code.

                      Tools            Platform
                      -----------      ------------

                ______Visual C++ _____ WIN32
               /
              /_______MBED (ARM)_______MBED (ARM dev board).
             /
            /_________GCC (x86)________Linux
           /
Source____/___________GCC (ARM)________GBA/DS
          \
           \__________SDA______________Verifone Verix CC Terminals
            \
             \________ARM SDT__________Verifine VerixV CC terminals
              \
               \______????_____________Renases M8/16/32.
                \
                 \____????_____________Z8 family.

The last two platforms I have good C compilers for but no C++.

As you can see I'm supporting a large variety of platforms and I share a large body of library code (and some app code).

Answer 1

Comeau C++ does this.

Answer 2

Out of date, but maybe you want to try cfront?

I'll leave this for information - cfront doesn't have exception support.

Answer 3

Comeau C++ generates C as its output, and they seem to be quite happy to port it to work with different back-end compilers, though I'm not sure about the exact pricing for that.

If you want a bit more of a "roll your own" approach, you could buy a license to the EDG C++ compiler. It's normally used as a front-end (e.g. by Comeau and Intel) but I believe as it's shipped, it includes a code generator that produces C as its output. Its licensing is oriented more toward compiler vendors, though, so a license gives you a lot of rights, but is pretty expensive.

Answer 4

If you use LLVM, llvm-g++ will compile your C++ code to LLVM bitcode, and llc has a backend which converts bitcode to C.

You could write commands like this:

llvm-g++ -emit-llvm -c foo.cpp -o foo.o
llc -march=c <foo.o >foo.c

Answer 5

Can't help with the Z8, but the Renesas M16C/M32C family has GCC these days - see http://www.kpitgnutools.com/ for prebuilt cross toolchain hosted on Windows. Haven't used it myself yet but may be a better option than a 3rd party C++ frontend, especially as your code already targets GCC on other platforms.

Answer 6

Of what I have understood, the c++ support in gcc for r8c/m16c/r32c isn't quite mature and good enough for production code. But for r8c/m16c/m32c/r32c there is at least one compiler supporting embedded C++ and that is IAR, I think Tasking also supports embedded C++ on m16c.