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properly copy attributed variables (#247)"

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This commit is contained in:
Mark Thom
2019-12-01 14:42:59 -07:00
parent e48f87fcf0
commit 9b71866b54
1 changed files with 26 additions and 63 deletions
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89
src/prolog/machine/copier.rs
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@@ -50,14 +50,6 @@ impl<T: CopierTarget> CopyTermState<T> {
&mut self.target[scan]
}
fn attr_var_redirect_tag(&self) -> impl Fn(usize) -> Addr {
if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
Addr::AttrVar
} else {
Addr::HeapCell
}
}
fn copied_list(&mut self, addr: usize) -> bool {
if let HeapCellValue::Addr(Addr::Lis(addr)) = self.target[addr].clone() {
if addr >= self.old_h {
@@ -79,62 +71,55 @@ impl<T: CopierTarget> CopyTermState<T> {
*self.value_at_scan() = HeapCellValue::Addr(Addr::Lis(threshold));
let hcv = self.target[addr].clone();
self.target.push(hcv.clone());
let ra = hcv.as_addr(threshold);
let rd = self.target.store(self.target.deref(ra));
match rd.clone() {
Addr::AttrVar(h) | Addr::HeapCell(h) if h >= self.old_h => {
self.target[threshold] = HeapCellValue::Addr(rd)
}
ra @ Addr::AttrVar(..) | ra @ Addr::HeapCell(_) | ra @ Addr::StackCell(..) => {
if ra == rd {
self.reinstantiate_var(ra, threshold);
} else {
self.target[threshold] = HeapCellValue::Addr(ra);
}
}
_ => {
self.trail
.push((Ref::HeapCell(addr), self.target[addr].clone()));
self.target[addr] = HeapCellValue::Addr(Addr::Lis(threshold))
}
};
self.target.push(hcv);
let hcv = self.target[addr + 1].clone();
self.target.push(hcv);
self.trail.push((Ref::HeapCell(addr), self.target[addr].clone()));
self.target[addr] = HeapCellValue::Addr(Addr::Lis(threshold));
self.scan += 1;
}
fn reinstantiate_var(&mut self, addr: Addr, threshold: usize) {
fn reinstantiate_var(&mut self, addr: Addr, frontier: usize) {
match addr {
Addr::HeapCell(h) => {
self.target[threshold] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.target[h] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.target[frontier] = HeapCellValue::Addr(Addr::HeapCell(frontier));
self.target[h] = HeapCellValue::Addr(Addr::HeapCell(frontier));
self.trail.push((
Ref::HeapCell(h),
HeapCellValue::Addr(Addr::HeapCell(h)),
));
}
Addr::StackCell(fr, sc) => {
self.target[threshold] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.target.stack()[fr][sc] = Addr::HeapCell(threshold);
self.target[frontier] = HeapCellValue::Addr(Addr::HeapCell(frontier));
self.target.stack()[fr][sc] = Addr::HeapCell(frontier);
self.trail.push((
Ref::StackCell(fr, sc),
HeapCellValue::Addr(Addr::StackCell(fr, sc)),
));
}
Addr::AttrVar(h) => {
let redirect_tag = self.attr_var_redirect_tag();
let threshold = if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
self.target.threshold()
} else {
frontier
};
self.target[threshold] = HeapCellValue::Addr(redirect_tag(threshold));
self.target[h] = HeapCellValue::Addr(redirect_tag(threshold));
self.target[frontier] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.target[h] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.trail.push((
Ref::AttrVar(h),
HeapCellValue::Addr(Addr::AttrVar(h)),
));
if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
self.target.push(HeapCellValue::Addr(Addr::AttrVar(threshold)));
let list_val = self.target[h + 1].clone();
self.target.push(list_val);
}
}
_ => unreachable!()
}
@@ -144,33 +129,12 @@ impl<T: CopierTarget> CopyTermState<T> {
let rd = self.target.store(self.target.deref(addr.clone()));
match rd.clone() {
Addr::AttrVar(h) if h >= self.old_h => {
let redirect_tag = self.attr_var_redirect_tag();
*self.value_at_scan() = HeapCellValue::Addr(redirect_tag(h));
self.scan += 1;
}
Addr::HeapCell(h) if h >= self.old_h => {
Addr::AttrVar(h) | Addr::HeapCell(h) if h >= self.old_h => {
*self.value_at_scan() = HeapCellValue::Addr(rd);
self.scan += 1;
}
Addr::AttrVar(h) if addr == rd => {
let redirect_tag = self.attr_var_redirect_tag();
let threshold = self.target.threshold();
self.target
.push(HeapCellValue::Addr(redirect_tag(threshold)));
if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
let list_val = self.target[h + 1].clone();
self.target.push(list_val);
}
self.reinstantiate_var(addr, threshold);
*self.value_at_scan() = HeapCellValue::Addr(redirect_tag(threshold));
}
_ if addr == rd => {
let scan = self.scan;
self.reinstantiate_var(addr, scan);
self.reinstantiate_var(addr, self.scan);
self.scan += 1;
}
_ => {
@@ -192,8 +156,7 @@ impl<T: CopierTarget> CopyTermState<T> {
HeapCellValue::NamedStr(arity, name.clone(), fixity.clone()),
));
self.target
.push(HeapCellValue::NamedStr(arity, name, fixity));
self.target.push(HeapCellValue::NamedStr(arity, name, fixity));
for i in 0..arity {
let hcv = self.target[addr + 1 + i].clone();