Multi-file compilation?

[adrianparvino]

Is there a way to build a single output from 2 files?

[shinh]

There is no linker. However, because EIR is a very simple text-based format, just concatenating EIR files may just work. Suppose you have these two files:

$ cat main.c
void foo();
int main() {
    foo();
}
$ cat foo.c
#include <stdio.h>
void foo() {
    puts("Hello, world!");
}

and you can do

$ out/8cc -S -I. -Ilibc -Iout foo.c -o foo.eir
$ out/8cc -S -I. -Ilibc -Iout main.c -o main.eir
$ cat foo.eir main.eir > linked.eir
$ out/elc linked.eir -rb linked.eir > linked.rb
$ ruby linked.rb
Hello, world!

Note that, as cat is not a linker, it cannot raise an error for symbols defined multiple times.

[shinh]

I realized the above wouldn't work for most cases since symbols generated by the compiler (e.g., .L1 for loops) will conflict with each other. Probably, the best workaround we can do today would be just concatenating all C source code to a single C source code before using the compiler. For example, see out/8cc.c after running make test-rb-full

[adrianparvino]

@shinh I am currently working on using clang as a linker, producing LLVM, and https://github.com/JuliaComputing/llvm-cbe to output C from LLVM, then compiling with ELVM.