mirrors/v
1
0
Fork 0
mirror of https://github.com/vlang/v.git synced 2025-09-13 14:32:26 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions 13

examples: add a brainfuck->wasm compiler example (#19492)

Browse source
This commit is contained in:
l-m 2023-10-02 11:42:02 +00:00 • committed by GitHub
parent 8d98a21ff8
commit 7ebee2ed36
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 132 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

132
examples/wasm_codegen/bf_compiler.v Normal file
View file

@ -0,0 +1,132 @@
import os
import wasm
const runtime_page = 1024 * 64 // 64 KiBs
fn generate_ciovec(mut start wasm.Function, sp wasm.LocalIndex) {
// construct struct __wasi_ciovec_t
//
// field, `const uint8_t *buf`
start.i32_const(runtime_page)
start.local_get(sp)
start.store(.i32_t, 2, 0)
// field, `__wasi_size_t buf_len`
start.i32_const(runtime_page)
start.i32_const(1) // len
start.store(.i32_t, 2, 4)
}
fn generate_code(mut start wasm.Function, bf_expr string) {
// locals are initialised to zero, by spec
sp := start.new_local_named(.i32_t, 'sp')
mut loop_labels := []wasm.LabelIndex{}
mut block_labels := []wasm.LabelIndex{}
// our page, the second one
for ch in bf_expr {
match ch {
`>` {
start.local_get(sp)
start.i32_const(1)
start.add(.i32_t)
start.local_set(sp)
}
`<` {
start.local_get(sp)
start.i32_const(1)
start.sub(.i32_t)
start.local_set(sp)
}
`+` {
start.local_get(sp)
{
start.local_get(sp)
start.load8(.i32_t, false, 0, 0)
start.i32_const(1)
start.add(.i32_t)
}
start.store8(.i32_t, 0, 0)
}
`-` {
start.local_get(sp)
{
start.local_get(sp)
start.load8(.i32_t, false, 0, 0)
start.i32_const(1)
start.sub(.i32_t)
}
start.store8(.i32_t, 0, 0)
}
`.` {
generate_ciovec(mut start, sp)
start.i32_const(1) // stdout
start.i32_const(runtime_page) // *iovs
start.i32_const(1) // iovs_len
start.i32_const(runtime_page + 1024) // *nwritten
start.call_import('wasi_unstable', 'fd_write')
start.drop() // ignore errno
}
`,` {
generate_ciovec(mut start, sp)
start.i32_const(0) // stdin
start.i32_const(runtime_page) // *iovs
start.i32_const(1) // iovs_len
start.i32_const(runtime_page + 1024) // *nwritten
start.call_import('wasi_unstable', 'fd_read')
start.drop() // ignore errno
}
`[` {
block_lbl := start.c_block([], [])
loop_lbl := start.c_loop([], [])
{
start.local_get(sp)
start.load8(.i32_t, false, 0, 0)
start.eqz(.i32_t)
start.c_br_if(block_lbl)
}
loop_labels << loop_lbl
block_labels << block_lbl
}
`]` {
loop_lbl := loop_labels.pop()
start.c_br(loop_lbl) // jump back to top
start.c_end(loop_lbl)
start.c_end(block_labels.pop())
}
else {}
}
}
}
@[noreturn]
fn usage() {
eprintln('Usage: bf <expr> <outfile>')
exit(1)
}
fn main() {
bf_expr := os.args[1] or { usage() }
outfile := os.args[2] or { usage() }
mut m := wasm.Module{}
m.enable_debug('wasm bf')
m.new_function_import('wasi_unstable', 'fd_write', [.i32_t, .i32_t, .i32_t, .i32_t],
[.i32_t])
m.new_function_import('wasi_unstable', 'fd_read', [.i32_t, .i32_t, .i32_t, .i32_t],
[.i32_t])
m.assign_memory('memory', true, 2, none)
mut start := m.new_function('_start', [], [])
{
generate_code(mut start, bf_expr)
}
m.commit(start, true)
bytes := m.compile()
os.write_file_array(outfile, bytes)!
}