c - How to write your own code generator backend for gcc?

Question

I have created my very own (very simple) byte code language, and a virtual machine to execute it. It works fine, but now I'd like to use gcc (or any other freely available compiler) to generate byte code for this machine from a normal c program. So the question is, how do I modify or extend gcc so that it can output my own byte code? Note that I do NOT want to compile my byte code to machine code, I want to "compile" c-code to (my own) byte code.

I realize that this is a potentially large question, and it is possible that the best answer is "go look at the gcc source code". I just need some help with how to get started with this. I figure that there must be some articles or books on this subject that could describe the process to add a custom generator to gcc, but I haven't found anything by googling.

question from:https://stackoverflow.com/questions/10617215/how-to-write-your-own-code-generator-backend-for-gcc

Answer 1

It is hard work.

For example I also design my own "architecture" with my own byte code and wanted to generate C/C++ code with GCC for it. This is the way how I make it:

1. At first you should read everything about porting in the manual of GCC.
2. Also not forget too read GCC Internals.
3. Read many things about Compilers.
4. Also look at this question and the answers here.
5. Google for more information.
6. Ask yourself if you are really ready.
7. Be sure to have a very good cafe machine... you will need it.
8. Start to add machine dependet files to gcc.
9. Compile gcc in a cross host-target way.
10. Check the code results in the Hex-Editor.
11. Do more tests.
12. Now have fun with your own architecture :D

When you are finished you can use c or c++ only without os-dependet libraries (you have currently no running OS on your architecture) and you should now (if you need it) compile many other libraries with your cross compiler to have a good framework.

PS: LLVM (Clang) is easier to port... maybe you want to start there?