53 lines
1.6 KiB
Rust
53 lines
1.6 KiB
Rust
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use crate::mir::{BasicBlockId, MirFunction, MirInstruction, ValueId};
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use std::cell::RefCell;
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thread_local! {
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static THROW_CTX: RefCell<Option<ThrowCtx>> = RefCell::new(None);
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}
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#[derive(Clone, Debug)]
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pub(super) struct ThrowCtx {
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pub(super) catch_bb: BasicBlockId,
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pub(super) incoming: Vec<(BasicBlockId, ValueId)>,
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}
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impl ThrowCtx {
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fn new(catch_bb: BasicBlockId) -> Self {
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Self { catch_bb, incoming: Vec::new() }
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}
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}
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pub(super) fn set(catch_bb: BasicBlockId) {
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THROW_CTX.with(|slot| {
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*slot.borrow_mut() = Some(ThrowCtx::new(catch_bb));
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});
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}
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pub(super) fn take() -> Option<ThrowCtx> {
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THROW_CTX.with(|slot| slot.borrow_mut().take())
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}
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pub(super) fn is_active() -> bool {
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THROW_CTX.with(|slot| slot.borrow().is_some())
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}
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/// Record a throw from `from_bb` with value `exc_val`. Sets terminator Jump to catch and
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/// appends predecessor+value to the incoming list. Returns the catch block id if active.
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pub(super) fn record_throw(f: &mut MirFunction, from_bb: BasicBlockId, exc_val: ValueId) -> Option<BasicBlockId> {
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THROW_CTX.with(|slot| {
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if let Some(ctx) = slot.borrow_mut().as_mut() {
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let target = ctx.catch_bb;
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if let Some(bb) = f.get_block_mut(from_bb) {
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bb.set_terminator(MirInstruction::Jump { target });
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}
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if let Some(succ) = f.get_block_mut(target) {
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succ.add_predecessor(from_bb);
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}
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ctx.incoming.push((from_bb, exc_val));
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Some(target)
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} else {
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None
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}
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})
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}
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