From 13f853464c99e2003b9b40d97ac0c32a05869d5f Mon Sep 17 00:00:00 2001 From: Chayim Refael Friedman Date: Sun, 6 Oct 2024 23:48:16 +0300 Subject: [PATCH] Use external stack in borrowck DFS Because damnit, it can crash r-a. Why do people make this stupid DFSes anyway (I get it, it's easier until it blows). --- crates/hir-ty/src/mir/borrowck.rs | 125 ++++++++++++++++-------------- 1 file changed, 67 insertions(+), 58 deletions(-) diff --git a/crates/hir-ty/src/mir/borrowck.rs b/crates/hir-ty/src/mir/borrowck.rs index 878d584a4e..9830fa1ca7 100644 --- a/crates/hir-ty/src/mir/borrowck.rs +++ b/crates/hir-ty/src/mir/borrowck.rs @@ -386,82 +386,91 @@ fn ever_initialized_map( fn dfs( db: &dyn HirDatabase, body: &MirBody, - b: BasicBlockId, l: LocalId, + stack: &mut Vec, result: &mut ArenaMap>, ) { - let mut is_ever_initialized = result[b][l]; // It must be filled, as we use it as mark for dfs - let block = &body.basic_blocks[b]; - for statement in &block.statements { - match &statement.kind { - StatementKind::Assign(p, _) => { - if p.projection.lookup(&body.projection_store).is_empty() && p.local == l { + while let Some(b) = stack.pop() { + let mut is_ever_initialized = result[b][l]; // It must be filled, as we use it as mark for dfs + let block = &body.basic_blocks[b]; + for statement in &block.statements { + match &statement.kind { + StatementKind::Assign(p, _) => { + if p.projection.lookup(&body.projection_store).is_empty() && p.local == l { + is_ever_initialized = true; + } + } + StatementKind::StorageDead(p) => { + if *p == l { + is_ever_initialized = false; + } + } + StatementKind::Deinit(_) + | StatementKind::FakeRead(_) + | StatementKind::Nop + | StatementKind::StorageLive(_) => (), + } + } + let Some(terminator) = &block.terminator else { + never!( + "Terminator should be none only in construction.\nThe body:\n{}", + body.pretty_print(db) + ); + return; + }; + let mut process = |target, is_ever_initialized| { + if !result[target].contains_idx(l) || !result[target][l] && is_ever_initialized { + result[target].insert(l, is_ever_initialized); + stack.push(target); + } + }; + match &terminator.kind { + TerminatorKind::Goto { target } => process(*target, is_ever_initialized), + TerminatorKind::SwitchInt { targets, .. } => { + targets.all_targets().iter().for_each(|&it| process(it, is_ever_initialized)); + } + TerminatorKind::UnwindResume + | TerminatorKind::Abort + | TerminatorKind::Return + | TerminatorKind::Unreachable => (), + TerminatorKind::Call { target, cleanup, destination, .. } => { + if destination.projection.lookup(&body.projection_store).is_empty() + && destination.local == l + { is_ever_initialized = true; } + target.iter().chain(cleanup).for_each(|&it| process(it, is_ever_initialized)); } - StatementKind::StorageDead(p) => { - if *p == l { - is_ever_initialized = false; - } + TerminatorKind::Drop { target, unwind, place: _ } => { + iter::once(target) + .chain(unwind) + .for_each(|&it| process(it, is_ever_initialized)); } - StatementKind::Deinit(_) - | StatementKind::FakeRead(_) - | StatementKind::Nop - | StatementKind::StorageLive(_) => (), - } - } - let Some(terminator) = &block.terminator else { - never!( - "Terminator should be none only in construction.\nThe body:\n{}", - body.pretty_print(db) - ); - return; - }; - let mut process = |target, is_ever_initialized| { - if !result[target].contains_idx(l) || !result[target][l] && is_ever_initialized { - result[target].insert(l, is_ever_initialized); - dfs(db, body, target, l, result); - } - }; - match &terminator.kind { - TerminatorKind::Goto { target } => process(*target, is_ever_initialized), - TerminatorKind::SwitchInt { targets, .. } => { - targets.all_targets().iter().for_each(|&it| process(it, is_ever_initialized)); - } - TerminatorKind::UnwindResume - | TerminatorKind::Abort - | TerminatorKind::Return - | TerminatorKind::Unreachable => (), - TerminatorKind::Call { target, cleanup, destination, .. } => { - if destination.projection.lookup(&body.projection_store).is_empty() - && destination.local == l - { - is_ever_initialized = true; + TerminatorKind::DropAndReplace { .. } + | TerminatorKind::Assert { .. } + | TerminatorKind::Yield { .. } + | TerminatorKind::CoroutineDrop + | TerminatorKind::FalseEdge { .. } + | TerminatorKind::FalseUnwind { .. } => { + never!("We don't emit these MIR terminators yet"); } - target.iter().chain(cleanup).for_each(|&it| process(it, is_ever_initialized)); - } - TerminatorKind::Drop { target, unwind, place: _ } => { - iter::once(target).chain(unwind).for_each(|&it| process(it, is_ever_initialized)); - } - TerminatorKind::DropAndReplace { .. } - | TerminatorKind::Assert { .. } - | TerminatorKind::Yield { .. } - | TerminatorKind::CoroutineDrop - | TerminatorKind::FalseEdge { .. } - | TerminatorKind::FalseUnwind { .. } => { - never!("We don't emit these MIR terminators yet"); } } } + let mut stack = Vec::new(); for &l in &body.param_locals { result[body.start_block].insert(l, true); - dfs(db, body, body.start_block, l, &mut result); + stack.clear(); + stack.push(body.start_block); + dfs(db, body, l, &mut stack, &mut result); } for l in body.locals.iter().map(|it| it.0) { db.unwind_if_cancelled(); if !result[body.start_block].contains_idx(l) { result[body.start_block].insert(l, false); - dfs(db, body, body.start_block, l, &mut result); + stack.clear(); + stack.push(body.start_block); + dfs(db, body, l, &mut stack, &mut result); } } result