On 11/11/2015 4:19 AM, Walter Bright wrote:
I've looked into generating C code as an output format. I found the problems to
be endemic and working around them was harder than just generating native code:
1. You're at the mercy of bugs in the C compiler you cannot fix.
2. C leaves quite a lot as "implementation defined", causing endless
compatibility issues with various C compilers.
3. C's integral promotion rules.
4. Generating exception handling code for C is miserable and inefficient.
5. Your compiler is going to be slower than C.
6. You'll suffer from endless bug reports caused by a mismatch between your
compiler and the user's C compiler, whatever that might be.
7. You cannot generate symbolic debug info in a format that looks like your
language's definitions.
8. C's symbols will differ from your program's symbols, again making use of a
debugger about like debugging code with an asm debugger, only much worse.
9. The generated C code will look awful.
10. The order of evaluation of C code expressions is implementation defined.
11. Installation problems, again, because you don't control the user's C
compiler.
12. If your language supports a basic type that isn't supported by C, tough
noogies (think SIMD types).
13. C has no concept of immutability or purity, so no hope of getting the C
optimizer to take advantage of that.
... and on ...
I forgot to add:
14. Many C compilers do not emit COMDATs, which cripples flexibility in emitting
code.
15. C doesn't give access to special features in the object file, which you may
need, such as weak externs, special sections, etc.
