makia wrote:I'm doing small lisp like compiler (to x86 asm) and what is bothering me is "runtime compilation", it's simple enough to do simple static C-like compiler with basic Lisp stuff (C runtime/gc and Lisp compiler emiting x86 asm) but i'm not sure how to do runtime compilation and all the problems that goes with it.
I assume that I can start extern gcc assembler each time from Lisp REPL and use C lib dynamic linker/loader (not pretty ?),
findinglisp wrote:Yup, take a look at ECL. When you call COMPILE-FILE in ECL, it effectively spits out a temporary .c file, invokes GCC on it, and then when you LOAD it, it dynamically loads the resulting dynamic lib.
Most other Lisp compilers don't work this way, BTW. Others, like SBCL, have their own compiler/assembler internal to the Lisp image and can generate assembly code directly into memory or to a file without the need of gcc.
makia wrote:I'm more interested in SBCL/CCL way, to assemble things directly into heap but i'm not sure how to implement this, obvious compiler need to have runtime support to push code into heap ... so it looks like that i dont know how to connect runtime and compiler to have working environment
Ramarren wrote:I played only a little with assembly, but as far as I know you just mark a heap region as executable if necessary, depending on your operating system (see NX bit on Wikipedia, mprotect syscall on Linux) and jump to it. Of course you need an assembler to generate the machine code which can be placed in memory directly. Other than that you don't need "runtime support to push code into heap" other than normal memory manipulation tools.
makia wrote:yes, i know that, but for example in ECL when you type function in REPL i doubt that you get compiled function (it does not invoke GCC)
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