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backtrack attributed variable bindings after failure (#242)

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This commit is contained in:
Mark Thom
2019-11-29 13:47:22 -04:00
parent 2d719ab6b7
commit 3e49db1a29
7 changed files with 90 additions and 74 deletions
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2
src/prolog/machine/attributed_variables.pl
View File

@@ -28,7 +28,7 @@ call_verify_attributes(Attrs, _, _, []) :-
call_verify_attributes([], _, _, []).
call_verify_attributes([Attr|Attrs], Var, Value, ListOfGoalLists) :-
gather_modules([Attr|Attrs], Modules0),
sort(Modules0, Modules),
sort(Modules0, Modules),
verify_attrs(Modules, Var, Value, ListOfGoalLists).
call_goals([ListOfGoalLists | ListsCubed]) :-

12
src/prolog/machine/attributed_variables.rs
View File

@@ -36,19 +36,25 @@ impl AttrVarInitializer {
self.attr_var_queue.clear();
self.bindings.clear();
}
#[inline]
pub(super) fn backtrack(&mut self, queue_b: usize, bindings_b: usize) {
self.attr_var_queue.truncate(queue_b);
self.bindings.truncate(bindings_b);
}
}
impl MachineState {
pub(super) fn push_attr_var_binding(&mut self, h: usize, addr: Addr) {
if self.attr_var_init.bindings.is_empty() {
self.attr_var_init.instigating_p = self.p.local();
if self.last_call {
self.attr_var_init.cp = self.cp;
} else {
self.attr_var_init.cp = self.p.local() + 1;
}
self.p = CodePtr::VerifyAttrInterrupt(self.attr_var_init.verify_attrs_loc);
}
@@ -61,6 +67,7 @@ impl MachineState {
.bindings
.iter()
.map(|(ref h, _)| Addr::AttrVar(*h));
let var_list_addr = Addr::HeapCell(self.heap.to_list(iter));
let iter = self
@@ -68,6 +75,7 @@ impl MachineState {
.bindings
.iter()
.map(|(_, ref addr)| addr.clone());
let value_list_addr = Addr::HeapCell(self.heap.to_list(iter));
(var_list_addr, value_list_addr)

82
src/prolog/machine/copier.rs
View File

@@ -58,34 +58,6 @@ impl<T: CopierTarget> CopyTermState<T> {
}
}
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()[fr][sc] = Addr::HeapCell(threshold);
self.trail.push((
Ref::StackCell(fr, sc),
HeapCellValue::Addr(Addr::StackCell(fr, sc)),
));
}
Addr::AttrVar(h) => {
let redirect_tag = self.attr_var_redirect_tag();
self.target[threshold] = HeapCellValue::Addr(redirect_tag(threshold));
self.target[h] = HeapCellValue::Addr(redirect_tag(threshold));
self.trail
.push((Ref::AttrVar(h), HeapCellValue::Addr(Addr::AttrVar(h))));
}
_ => {}
}
}
fn copied_list(&mut self, addr: usize) -> bool {
if let HeapCellValue::Addr(Addr::Lis(addr)) = self.target[addr].clone() {
if addr >= self.old_h {
@@ -113,22 +85,10 @@ impl<T: CopierTarget> CopyTermState<T> {
let rd = self.target.store(self.target.deref(ra));
match rd.clone() {
Addr::AttrVar(h) if h >= self.old_h => {
let redirect_tag = self.attr_var_redirect_tag();
self.target[threshold] = HeapCellValue::Addr(redirect_tag(h));
}
Addr::HeapCell(h) if h >= self.old_h => {
Addr::AttrVar(h) | Addr::HeapCell(h) if h >= self.old_h => {
self.target[threshold] = HeapCellValue::Addr(rd)
}
Addr::AttrVar(h) => {
if Addr::AttrVar(h) == rd {
self.reinstantiate_var(Addr::AttrVar(h), threshold);
} else {
let redirect_tag = self.attr_var_redirect_tag();
self.target[threshold] = HeapCellValue::Addr(redirect_tag(h));
}
}
ra @ Addr::HeapCell(..) | ra @ Addr::StackCell(..) => {
ra @ Addr::AttrVar(..) | ra @ Addr::HeapCell(_) | ra @ Addr::StackCell(..) => {
if ra == rd {
self.reinstantiate_var(ra, threshold);
} else {
@@ -148,6 +108,38 @@ impl<T: CopierTarget> CopyTermState<T> {
self.scan += 1;
}
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()[fr][sc] = Addr::HeapCell(threshold);
self.trail.push((
Ref::StackCell(fr, sc),
HeapCellValue::Addr(Addr::StackCell(fr, sc)),
));
}
Addr::AttrVar(h) => {
let redirect_tag = self.attr_var_redirect_tag();
self.target[threshold] = HeapCellValue::Addr(redirect_tag(threshold));
self.target[h] = HeapCellValue::Addr(redirect_tag(threshold));
self.trail.push((
Ref::AttrVar(h),
HeapCellValue::Addr(Addr::AttrVar(h)),
));
}
_ => unreachable!()
}
}
fn copy_var(&mut self, addr: Addr) {
let rd = self.target.store(self.target.deref(addr.clone()));
@@ -168,7 +160,7 @@ impl<T: CopierTarget> CopyTermState<T> {
self.target
.push(HeapCellValue::Addr(redirect_tag(threshold)));
if let Addr::AttrVar(_) = redirect_tag(threshold) {
if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
let list_val = self.target[h + 1].clone();
self.target.push(list_val);
}
@@ -181,7 +173,9 @@ impl<T: CopierTarget> CopyTermState<T> {
self.reinstantiate_var(addr, scan);
self.scan += 1;
}
_ => *self.value_at_scan() = HeapCellValue::Addr(rd),
_ => {
*self.value_at_scan() = HeapCellValue::Addr(rd);
}
}
}

48
src/prolog/machine/machine_state.rs
View File

@@ -445,11 +445,13 @@ pub(crate) trait CallPolicy: Any {
machine_st.heap.truncate(machine_st.or_stack[b].h);
let attr_var_init_b = machine_st.or_stack[b].attr_var_init_b;
machine_st
.attr_var_init
.attr_var_queue
.truncate(attr_var_init_b);
let attr_var_init_queue_b = machine_st.or_stack[b].attr_var_init_queue_b;
let attr_var_init_bindings_b = machine_st.or_stack[b].attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.hb = machine_st.heap.h;
machine_st.p += 1;
@@ -491,11 +493,13 @@ pub(crate) trait CallPolicy: Any {
machine_st.heap.truncate(machine_st.or_stack[b].h);
let attr_var_init_b = machine_st.or_stack[b].attr_var_init_b;
machine_st
.attr_var_init
.attr_var_queue
.truncate(attr_var_init_b);
let attr_var_init_queue_b = machine_st.or_stack[b].attr_var_init_queue_b;
let attr_var_init_bindings_b = machine_st.or_stack[b].attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.hb = machine_st.heap.h;
machine_st.p += offset;
@@ -533,11 +537,13 @@ pub(crate) trait CallPolicy: Any {
machine_st.heap.truncate(machine_st.or_stack[b].h);
let attr_var_init_b = machine_st.or_stack[b].attr_var_init_b;
machine_st
.attr_var_init
.attr_var_queue
.truncate(attr_var_init_b);
let attr_var_init_queue_b = machine_st.or_stack[b].attr_var_init_queue_b;
let attr_var_init_bindings_b = machine_st.or_stack[b].attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.b = machine_st.or_stack[b].b;
machine_st.or_stack.truncate(machine_st.b);
@@ -580,12 +586,14 @@ pub(crate) trait CallPolicy: Any {
machine_st.heap.truncate(machine_st.or_stack[b].h);
let attr_var_init_b = machine_st.or_stack[b].attr_var_init_b;
machine_st
.attr_var_init
.attr_var_queue
.truncate(attr_var_init_b);
let attr_var_init_queue_b = machine_st.or_stack[b].attr_var_init_queue_b;
let attr_var_init_bindings_b = machine_st.or_stack[b].attr_var_init_bindings_b;
machine_st.attr_var_init.backtrack(
attr_var_init_queue_b,
attr_var_init_bindings_b,
);
machine_st.b = machine_st.or_stack[b].b;
machine_st.or_stack.truncate(machine_st.b);

2
src/prolog/machine/machine_state_impl.rs
View File

@@ -3300,6 +3300,7 @@ impl MachineState {
self.e,
self.cp.clone(),
self.attr_var_init.attr_var_queue.len(),
self.attr_var_init.bindings.len(),
self.b,
self.p.clone() + 1,
self.tr,
@@ -3339,6 +3340,7 @@ impl MachineState {
self.e,
self.cp.clone(),
self.attr_var_init.attr_var_queue.len(),
self.attr_var_init.bindings.len(),
self.b,
self.p.clone() + offset,
self.tr,

15
src/prolog/machine/or_stack.rs
View File

@@ -8,7 +8,8 @@ pub struct Frame {
pub global_index: usize,
pub e: usize,
pub cp: LocalCodePtr,
pub attr_var_init_b: usize,
pub attr_var_init_queue_b: usize,
pub attr_var_init_bindings_b: usize,
pub b: usize,
pub bp: CodePtr,
pub tr: usize,
@@ -23,7 +24,8 @@ impl Frame {
global_index: usize,
e: usize,
cp: LocalCodePtr,
attr_var_init_b: usize,
attr_var_init_queue_b: usize,
attr_var_init_bindings_b: usize,
b: usize,
bp: CodePtr,
tr: usize,
@@ -36,7 +38,8 @@ impl Frame {
global_index,
e,
cp,
attr_var_init_b,
attr_var_init_queue_b,
attr_var_init_bindings_b,
b,
bp,
tr,
@@ -64,7 +67,8 @@ impl OrStack {
global_index: usize,
e: usize,
cp: LocalCodePtr,
attr_var_init_b: usize,
attr_var_init_queue_b: usize,
attr_var_init_bindings_b: usize,
b: usize,
bp: CodePtr,
tr: usize,
@@ -77,7 +81,8 @@ impl OrStack {
global_index,
e,
cp,
attr_var_init_b,
attr_var_init_queue_b,
attr_var_init_bindings_b,
b,
bp,
tr,

3
src/prolog/toplevel.pl
View File

@@ -44,8 +44,7 @@
),
( '$get_b_value'(B), call(Term), '$write_eqs_and_read_input'(B, VarList), !
; write('false.'), nl
),
'$reset_attr_var_state'.
).
'$needs_bracketing'(Value, Op) :-
catch((functor(Value, F, _),