Noratrieb/brainfuck
1
0
Fork 0
mirror of https://github.com/Noratrieb/brainfuck.git synced 2026-01-14 21:35:02 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

docs

Browse source
This commit is contained in:
nora 2022-04-17 18:39:06 +02:00
parent f88c486088
commit 039b5ea9c7
7 changed files with 156 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

26
rust2/src/mir/mod.rs
View file

@ -1,4 +1,18 @@
//! an experimental MIR (mid-level-ir)
//!
//! The MIR consists of two parts. First, there are instructions (`Stmt`). These instructions
//! can be seen as an extended version of the default brainfuck instruction set `+-<>,.[]`.
//! These instructions modify the classic tape. What MIR does is that it attaches an abstract
//! `MemoryState` to *each* statement. This state contains all facts known about the state of the
//! tape at the point of execution of the statement.
//!
//! For example, for the code `++.`, the `MemoryState` for the `.` instruction contains a single
//! fact: "The current cell was written to, by the instruction before and with the value 2". MIR
//! tracks as much of the reads/writes to determine their dependencies and eliminate as many
//! of them as possible.
//!
//! Note that MIR is always pessimized, so if it can't determine for sure that something is true,
//! it will not act on it.
#![allow(dead_code)]
mod opts;
@ -10,7 +24,7 @@ use bumpalo::Bump;
use crate::{
hir::{Hir, StmtKind as HirStmtKind},
mir::state::{MemoryState, Store, StoreInner},
mir::state::{Load, MemoryState, Store},
parse::Span,
BumpVec,
};
@ -48,8 +62,8 @@ enum StmtKind<'mir> {
},
/// Left or Right pointer move (`<>`)
PointerMove(i32),
Loop(Mir<'mir>),
Out,
Loop(Mir<'mir>, Load),
Out(Load),
In(Store),
SetN(u8, Store),
}
@ -77,9 +91,9 @@ fn hir_to_mir<'mir>(alloc: &'mir Bump, hir: &Hir<'_>) -> Mir<'mir> {
},
HirStmtKind::Right(n) => StmtKind::PointerMove(i32::try_from(n).unwrap()),
HirStmtKind::Left(n) => StmtKind::PointerMove(-i32::try_from(n).unwrap()),
HirStmtKind::Loop(ref body) => StmtKind::Loop(hir_to_mir(alloc, body)),
HirStmtKind::Out => StmtKind::Out,
HirStmtKind::In => StmtKind::In(StoreInner::Unknown.into()),
HirStmtKind::Loop(ref body) => StmtKind::Loop(hir_to_mir(alloc, body), Load::Unknown),
HirStmtKind::Out => StmtKind::Out(Load::Unknown),
HirStmtKind::In => StmtKind::In(Store::unknown()),
HirStmtKind::SetN(n) => StmtKind::SetN(n, Store::unknown()),
};
Stmt {