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add s pointers for strings and partial strings, put_unsafe_value calls store earlier to avoid unnecessary heap writes (#273)

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This commit is contained in:
Mark Thom
2020-02-28 23:42:40 -07:00
parent aa5f186a96
commit 2ebcd673c8
3 changed files with 77 additions and 66 deletions
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28
src/prolog/machine/machine_state.rs
View File

@@ -18,6 +18,7 @@ use std::cmp::Ordering;
use std::io::{stdout, Write};
use std::mem;
use std::ops::{Index, IndexMut};
use std::rc::Rc;
pub struct Ball {
pub(super) boundary: usize,
@@ -245,8 +246,33 @@ pub(super) enum MachineMode {
Write,
}
#[derive(Clone)]
pub(super) enum HeapPtr {
HeapCell(usize),
PStrLocation(usize, usize),
String(usize, Rc<String>),
}
impl HeapPtr {
#[inline]
pub(super)
fn as_addr(&self) -> Addr {
match self {
&HeapPtr::HeapCell(h) => Addr::HeapCell(h),
&HeapPtr::PStrLocation(h, n) => Addr::PStrLocation(h, n),
&HeapPtr::String(n, ref s) => Addr::Con(Constant::String(n, s.clone())),
}
}
}
impl Default for HeapPtr {
fn default() -> Self {
HeapPtr::HeapCell(0)
}
}
pub struct MachineState {
pub(super) s: usize,
pub(super) s: HeapPtr,
pub(super) p: CodePtr,
pub(super) b: usize,
pub(super) b0: usize,

113
src/prolog/machine/machine_state_impl.rs
View File

@@ -52,7 +52,7 @@ impl MachineState {
pub(crate)
fn new() -> Self {
MachineState {
s: 0,
s: HeapPtr::default(),
p: CodePtr::default(),
b: 0,
b0: 0,
@@ -82,7 +82,7 @@ impl MachineState {
pub(crate)
fn with_small_heap() -> Self {
MachineState {
s: 0,
s: HeapPtr::default(),
p: CodePtr::default(),
b: 0,
b0: 0,
@@ -645,6 +645,33 @@ impl MachineState {
}
}
fn increment_s_ptr(&mut self, rhs: usize) {
match &mut self.s {
HeapPtr::HeapCell(ref mut h) => {
*h += rhs;
}
HeapPtr::PStrLocation(h, n) => {
match &self.heap[*h] {
HeapCellValue::PartialString(ref pstr) => {
let s = pstr.block_as_str();
for c in s[*n ..].chars().take(rhs) {
*n += c.len_utf8();
}
}
_ => {
unreachable!()
}
}
}
HeapPtr::String(ref mut n, ref s) => {
for c in s[*n ..].chars().take(rhs) {
*n += c.len_utf8();
}
}
}
}
pub(super)
fn unwind_trail(&mut self, a1: usize, a2: usize) {
// the sequence is reversed to respect the chronology of trail
@@ -1564,45 +1591,6 @@ impl MachineState {
};
}
fn get_char_list(&mut self, offset: usize, s: Rc<String>)
{
if let Some(c) = s[offset ..].chars().next() {
let h = self.heap.h();
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::Char(c))));
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::String(
offset + c.len_utf8(),
s,
))));
self.s = h;
self.mode = MachineMode::Read;
}
}
fn get_partial_string_list(&mut self, pstr_h: usize, offset: usize)
{
let (c, pstr_tail) =
if let HeapCellValue::PartialString(ref pstr) = &self.heap[pstr_h] {
let s = pstr.block_as_str();
if let Some(c) = s[offset ..].chars().next() {
(c, Addr::PStrTail(pstr_h, offset + c.len_utf8()))
} else {
unreachable!()
}
} else {
unreachable!()
};
self.s = self.heap.h();
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::Char(c))));
self.heap.push(HeapCellValue::Addr(pstr_tail));
self.mode = MachineMode::Read;
}
pub(super)
fn execute_fact_instr(&mut self, instr: &FactInstruction) {
match instr {
@@ -1618,14 +1606,16 @@ impl MachineState {
match self.flags.double_quotes {
DoubleQuotes::Chars | DoubleQuotes::Codes
if s.len() > n => {
self.get_char_list(n, s)
self.s = HeapPtr::String(n, s);
self.mode = MachineMode::Read;
}
_ => {
self.fail = true
}
},
Addr::PStrLocation(h, n) => {
self.get_partial_string_list(h, n)
self.s = HeapPtr::PStrLocation(h, n);
self.mode = MachineMode::Read;
}
addr @ Addr::AttrVar(_)
| addr @ Addr::StackCell(..)
@@ -1639,7 +1629,7 @@ impl MachineState {
self.mode = MachineMode::Write;
}
Addr::Lis(a) => {
self.s = a;
self.s = HeapPtr::HeapCell(a);
self.mode = MachineMode::Read;
}
_ => self.fail = true,
@@ -1654,7 +1644,7 @@ impl MachineState {
if let &HeapCellValue::NamedStr(narity, ref s, _) = result {
if narity == arity && ct.name() == *s {
self.s = a + 1;
self.s = HeapPtr::HeapCell(a + 1);
self.mode = MachineMode::Read;
} else {
self.fail = true;
@@ -1685,7 +1675,7 @@ impl MachineState {
&FactInstruction::UnifyConstant(ref c) => {
match self.mode {
MachineMode::Read => {
let addr = Addr::HeapCell(self.s);
let addr = self.s.as_addr();
self.write_constant_to_var(addr, c.clone());
}
MachineMode::Write => {
@@ -1693,11 +1683,11 @@ impl MachineState {
}
};
self.s += 1;
self.increment_s_ptr(1);
}
&FactInstruction::UnifyVariable(reg) => {
match self.mode {
MachineMode::Read => self[reg] = self.heap[self.s].as_addr(self.s),
MachineMode::Read => self[reg] = self.s.as_addr(),
MachineMode::Write => {
let h = self.heap.h();
@@ -1706,15 +1696,13 @@ impl MachineState {
}
};
self.s += 1;
self.increment_s_ptr(1);
}
&FactInstruction::UnifyLocalValue(reg) => {
let s = self.s;
match self.mode {
MachineMode::Read => {
let reg_addr = self[reg].clone();
self.unify(reg_addr, Addr::HeapCell(s));
self.unify(reg_addr, self.s.as_addr());
}
MachineMode::Write => {
let addr = self.deref(self[reg].clone());
@@ -1725,7 +1713,7 @@ impl MachineState {
let val = self.heap[hc].clone();
self.heap.push(val);
self.s += 1;
self.increment_s_ptr(1);
return;
}
@@ -1736,15 +1724,13 @@ impl MachineState {
}
};
self.s += 1;
self.increment_s_ptr(1);
}
&FactInstruction::UnifyValue(reg) => {
let s = self.s;
match self.mode {
MachineMode::Read => {
let reg_addr = self[reg].clone();
self.unify(reg_addr, Addr::HeapCell(s));
self.unify(reg_addr, self.s.as_addr());
}
MachineMode::Write => {
let heap_val = self.store(self[reg].clone());
@@ -1752,11 +1738,11 @@ impl MachineState {
}
};
self.s += 1;
self.increment_s_ptr(1);
}
&FactInstruction::UnifyVoid(n) => {
match self.mode {
MachineMode::Read => self.s += n,
MachineMode::Read => self.increment_s_ptr(n),
MachineMode::Write => {
let h = self.heap.h();
@@ -1865,16 +1851,15 @@ impl MachineState {
&QueryInstruction::PutStructure(ref ct, arity, reg) => {
let h = self.heap.h();
self.heap
.push(HeapCellValue::NamedStr(arity, ct.name(), ct.spec()));
self.heap.push(HeapCellValue::NamedStr(arity, ct.name(), ct.spec()));
self[reg] = Addr::Str(h);
}
&QueryInstruction::PutUnsafeValue(n, arg) => {
let e = self.e;
let addr = self.deref(Addr::StackCell(e, n));
let addr = self.store(self.deref(Addr::StackCell(e, n)));
if addr.is_protected(e) {
self.registers[arg] = self.store(addr);
self.registers[arg] = addr;
} else {
let h = self.heap.h();
@@ -3454,7 +3439,7 @@ impl MachineState {
self.e = 0;
self.b = 0;
self.b0 = 0;
self.s = 0;
self.s = HeapPtr::default();
self.tr = 0;
self.p = CodePtr::default();
self.cp = LocalCodePtr::default();

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

@@ -699,7 +699,7 @@ impl Machine {
snapshot.e = self.machine_st.e;
snapshot.b = self.machine_st.b;
snapshot.b0 = self.machine_st.b0;
snapshot.s = self.machine_st.s;
snapshot.s = self.machine_st.s.clone();
snapshot.tr = self.machine_st.tr;
snapshot.num_of_args = self.machine_st.num_of_args;