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reconcile latest changes against stack changes

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This commit is contained in:
Mark Thom
2019-12-07 18:59:03 -07:00
parent 3d2c4f0801 5ccd334555
commit d6e75110a5
14 changed files with 302 additions and 143 deletions
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143
src/prolog/machine/copier.rs
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@@ -5,6 +5,12 @@ use std::ops::IndexMut;
type Trail = Vec<(Ref, HeapCellValue)>;
#[derive(Clone, Copy)]
pub enum AttrVarPolicy {
DeepCopy,
StripAttributes
}
pub(crate) trait CopierTarget: IndexMut<usize, Output = HeapCellValue> {
fn threshold(&self) -> usize;
fn push(&mut self, _: HeapCellValue);
@@ -13,9 +19,10 @@ pub(crate) trait CopierTarget: IndexMut<usize, Output = HeapCellValue> {
fn stack(&mut self) -> &mut Stack;
}
pub(crate) fn copy_term<T: CopierTarget>(target: T, addr: Addr) {
let mut copy_term_state = CopyTermState::new(target);
copy_term_state.copy_term_impl(addr);
pub(crate)
fn copy_term<T: CopierTarget>(target: T, addr: Addr, attr_var_policy: AttrVarPolicy) {
let mut copy_term_state = CopyTermState::new(target, attr_var_policy);
copy_term_state.copy_term_impl(addr);
}
struct CopyTermState<T: CopierTarget> {
@@ -23,15 +30,17 @@ struct CopyTermState<T: CopierTarget> {
scan: usize,
old_h: usize,
target: T,
attr_var_policy: AttrVarPolicy
}
impl<T: CopierTarget> CopyTermState<T> {
fn new(target: T) -> Self {
fn new(target: T, attr_var_policy: AttrVarPolicy) -> Self {
CopyTermState {
trail: vec![],
scan: 0,
old_h: target.threshold(),
target,
attr_var_policy
}
}
@@ -41,40 +50,17 @@ impl<T: CopierTarget> CopyTermState<T> {
&mut self.target[scan]
}
fn reinstantiate_var(&mut self, addr: Addr, threshold: usize) {
match addr {
Addr::HeapCell(h) => {
self.target[threshold] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.target[h] = HeapCellValue::Addr(Addr::HeapCell(threshold));
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().index_and_frame_mut(fr)[sc] = Addr::HeapCell(threshold);
self.trail.push((
Ref::StackCell(fr, sc),
HeapCellValue::Addr(Addr::StackCell(fr, sc)),
));
}
Addr::AttrVar(h) => {
self.target[threshold] = HeapCellValue::Addr(Addr::AttrVar(threshold));
self.target[h] = HeapCellValue::Addr(Addr::AttrVar(threshold));
self.trail
.push((Ref::AttrVar(h), HeapCellValue::Addr(Addr::AttrVar(h))));
fn copied_list(&mut self, addr: usize) -> bool {
match self.target[addr].clone() {
HeapCellValue::Addr(Addr::Lis(addr)) | HeapCellValue::Addr(Addr::HeapCell(addr)) => {
if addr >= self.old_h {
*self.value_at_scan() = HeapCellValue::Addr(Addr::Lis(addr));
self.scan += 1;
return true;
}
}
_ => {}
}
}
fn copied_list(&mut self, addr: usize) -> bool {
if let HeapCellValue::Addr(Addr::Lis(addr)) = self.target[addr].clone() {
if addr >= self.old_h {
*self.value_at_scan() = HeapCellValue::Addr(Addr::Lis(addr));
self.scan += 1;
return true;
}
}
};
false
}
@@ -88,11 +74,15 @@ 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));
self.target.push(hcv);
let hcv = self.target[addr + 1].clone();
self.target.push(hcv);
match rd.clone() {
Addr::AttrVar(h) | Addr::HeapCell(h) if h >= self.old_h => {
self.target[threshold] = HeapCellValue::Addr(rd)
@@ -100,23 +90,67 @@ impl<T: CopierTarget> CopyTermState<T> {
ra @ Addr::AttrVar(_) | ra @ Addr::HeapCell(..) | ra @ Addr::StackCell(..) => {
if ra == rd {
self.reinstantiate_var(ra, threshold);
if let AttrVarPolicy::StripAttributes = self.attr_var_policy {
self.trail.push((Ref::HeapCell(addr), self.target[addr].clone()));
self.target[addr] = HeapCellValue::Addr(Addr::HeapCell(threshold));
}
} else {
self.target[threshold] = HeapCellValue::Addr(ra);
}
}
_ => {
self.trail
.push((Ref::HeapCell(addr), self.target[addr].clone()));
self.trail.push((Ref::HeapCell(addr), self.target[addr].clone()));
self.target[addr] = HeapCellValue::Addr(Addr::Lis(threshold))
}
};
let hcv = self.target[addr + 1].clone();
self.target.push(hcv);
self.scan += 1;
}
fn reinstantiate_var(&mut self, addr: Addr, frontier: usize) {
match addr {
Addr::HeapCell(h) => {
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[frontier] = HeapCellValue::Addr(Addr::HeapCell(frontier));
self.target.stack().index_and_frame_mut(fr)[sc] = Addr::HeapCell(frontier);
self.trail.push((
Ref::StackCell(fr, sc),
HeapCellValue::Addr(Addr::StackCell(fr, sc)),
));
}
Addr::AttrVar(h) => {
let threshold = if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
self.target.threshold()
} else {
frontier
};
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!()
}
}
fn copy_var(&mut self, addr: Addr) {
let rd = self.target.store(self.target.deref(addr.clone()));
@@ -125,23 +159,13 @@ impl<T: CopierTarget> CopyTermState<T> {
*self.value_at_scan() = HeapCellValue::Addr(rd);
self.scan += 1;
}
Addr::AttrVar(h) if addr == rd => {
let threshold = self.target.threshold();
self.target
.push(HeapCellValue::Addr(Addr::AttrVar(threshold)));
let list_val = self.target[h + 1].clone();
self.target.push(list_val);
self.reinstantiate_var(addr, threshold);
*self.value_at_scan() = HeapCellValue::Addr(Addr::AttrVar(threshold));
}
_ if addr == rd => {
let scan = self.scan;
self.reinstantiate_var(addr, scan);
self.reinstantiate_var(addr, self.scan);
self.scan += 1;
}
_ => *self.value_at_scan() = HeapCellValue::Addr(rd),
_ => {
*self.value_at_scan() = HeapCellValue::Addr(rd);
}
}
}
@@ -158,8 +182,7 @@ 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();
@@ -185,8 +208,8 @@ impl<T: CopierTarget> CopyTermState<T> {
HeapCellValue::Addr(addr) => match addr {
Addr::Lis(addr) => self.copy_list(addr),
addr @ Addr::AttrVar(_)
| addr @ Addr::HeapCell(_)
| addr @ Addr::StackCell(..) => self.copy_var(addr),
| addr @ Addr::HeapCell(_)
| addr @ Addr::StackCell(..) => self.copy_var(addr),
Addr::Str(addr) => self.copy_structure(addr),
Addr::Con(_) | Addr::DBRef(_) => self.scan += 1,
},