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remove bounds check

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This commit is contained in:
nora 2022-04-15 18:57:39 +02:00
parent 2df17352d1
commit 1e1a2a277b
3 changed files with 29 additions and 6 deletions
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15
rust2/src/codegen_interpreter.rs
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@ -30,13 +30,22 @@ where
mem: [Wrapping(0u8); MEM_SIZE],
};
interpreter.execute();
// SAFETY: `Code` can only be produced by the `crate::codegen` module, which is trusted to not
// produce out of bounds jumps and put the `End` at the end
unsafe {
interpreter.execute();
}
}
impl<'c, W: Write, R: Read> Interpreter<'c, W, R> {
fn execute(&mut self) {
unsafe fn execute(&mut self) {
let stmts = self.code.stmts();
loop {
let instr = self.code.stmts[self.ip];
// SAFETY: If the code ends with an `End` and there are no out of bounds jumps,
// `self.ip` will never be out of bounds
// Removing this bounds check speeds up execution by about 40%
debug_assert!(self.ip < stmts.len());
let instr = unsafe { *stmts.get_unchecked(self.ip) };
self.ip += 1;
match instr {
Stmt::Add(n) => {