raven lion
sample code:
fn number(n: u32) u32{
if(n > 10) return 0;
return n;
}
fn main() {
const x = number(11);
const y = number(9);
}
after comptime the code is following?(I guess the fn number don't use anywhere, maybe remove it)
fn main() {
const x = 0;
const y = 9;
}
any way can show the code after comptime?
mint flicker
there's no way to do this, this isn't how comptime works.
unlike macros, comptime isn't a preprocess, but tied into the analysis of zig itself.
raven lion
y, it is not macros.
but it is useful for learning zig language
mint flicker
i dont really see how
you can use @compileLog to print comptime known values if that helps
raven lion
o, i will try it
if the fn number don't use anywhere after comptime, will zig remove it?
mint flicker
it can be optimized away sure, non-exported symbols in zig are considered local
raven lion
the @compileLog is good at learning zig.
but if we want to know that what exact code for "inline or generic". it don't work
thanks your answer.
astral stream
the @compileLog is good at learning zig.
but if we want to know that what exact...
comptime does not generate code
therefor you cannot "output" the resulting code
since there is none
your comptime function is interpreted at compile time
its not a macro
raven lion
i got, its not a macro.
i mean: what exact code for "inline or generic" after build(not comptime)
astral stream
do you mean the resulting assembly? you can just disassemble the binary
easiest way to see the resulting assembly is godbolt https://godbolt.org/
raven lion
y, assemble is a way, its more difficult way
astral stream
more difficult than what?
your comptime/generic functions are compiled into an intermediate assembly and interpreted
there's no code to view
swift mica
-femit-llvm-ir is another option.
raven lion
its very difficult way to understand/learn zig lang. no "more" word (my en is not good)
swift mica
yes. You can get an idea of what's happening but it's certainly not an easy solution. On second thought I'd prefer objdump/godbolt to the IR in most cases.
mint flicker
or just learn zig, and read the source code...
have you looked at the language reference?
swift mica
what you're looking for just isn't present AFAIK. There's no "after generic" code to view because generic is just more comptime.
raven lion
got.
in blog : https://kristoff.it/blog/what-is-zig-comptime/
I see the follow :
var acc: i64 = 0;
acc +%= num;
acc *%= num;
acc -%= num;
acc -%= num;
return acc;
then I want to know , can show the code after build.
astral stream
look at godbolt
it shows the resulting assembly
there is no "code after build", only the varying levels of assembly/IRs
raven lion
got, thanks
swift mica
export fn thing(num: i64) i64 {
var acc: i64 = 0;
acc +%= num;
acc *%= num;
acc -%= num;
acc -%= num;
return acc;
}
you can do it locally:
$ zig build-obj z98.zig -OReleaseFast
$ objdump -S z98.o
z98.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <thing>:
export fn thing(num: i64) i64 {
var acc: i64 = 0;
acc +%= num;
acc *%= num;
acc -%= num;
acc -%= num;
0: 48 8d 47 fe lea -0x2(%rdi),%rax
4: 48 0f af c7 imul %rdi,%rax
return acc;
8: c3 ret