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begin to mark registers as safe from built-in predicates like is/2 (#1545)

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This commit is contained in:
Mark Thom
2022-11-13 21:43:14 -07:00
parent c90dd80ece
commit d19a8d6b98
1 changed files with 38 additions and 18 deletions
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56
src/fixtures.rs
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@@ -257,6 +257,7 @@ pub(crate) struct UnsafeVarMarker {
pub(crate) unsafe_temp_vars: IndexSet<usize>, pub(crate) unsafe_temp_vars: IndexSet<usize>,
pub(crate) safe_perm_vars: IndexSet<usize>, pub(crate) safe_perm_vars: IndexSet<usize>,
pub(crate) safe_temp_vars: IndexSet<usize>, pub(crate) safe_temp_vars: IndexSet<usize>,
pub(crate) temp_vars_to_perm_vars: IndexMap<usize, usize>,
} }
impl UnsafeVarMarker { impl UnsafeVarMarker {
@@ -266,6 +267,7 @@ impl UnsafeVarMarker {
unsafe_temp_vars: IndexSet::new(), unsafe_temp_vars: IndexSet::new(),
safe_perm_vars: IndexSet::new(), safe_perm_vars: IndexSet::new(),
safe_temp_vars: IndexSet::new(), safe_temp_vars: IndexSet::new(),
temp_vars_to_perm_vars: IndexMap::new(),
} }
} }
@@ -301,6 +303,8 @@ impl UnsafeVarMarker {
} }
} }
// returns true if the instruction at *query_instr cannot be
// changed by mark_unsafe_vars.
fn mark_safe_vars(&mut self, query_instr: &Instruction) -> bool { fn mark_safe_vars(&mut self, query_instr: &Instruction) -> bool {
match query_instr { match query_instr {
&Instruction::PutVariable(r @ RegType::Temp(_), _) | &Instruction::PutVariable(r @ RegType::Temp(_), _) |
@@ -308,6 +312,17 @@ impl UnsafeVarMarker {
self.mark_var_as_safe(r); self.mark_var_as_safe(r);
true true
} }
&Instruction::PutVariable(RegType::Perm(p), t) => {
self.temp_vars_to_perm_vars.insert(t, p);
true
}
&Instruction::CallIs(RegType::Temp(t), ..) => {
if let Some(p) = self.temp_vars_to_perm_vars.get(&t) {
self.mark_var_as_safe(RegType::Perm(*p));
}
true
}
_ => false, _ => false,
} }
} }
@@ -324,34 +339,37 @@ impl UnsafeVarMarker {
fn mark_unsafe_perm_vars(&mut self, query_instr: &mut Instruction, phase: usize) { fn mark_unsafe_perm_vars(&mut self, query_instr: &mut Instruction, phase: usize) {
match query_instr { match query_instr {
&mut Instruction::PutValue(RegType::Perm(p), arg) => { &mut Instruction::PutValue(RegType::Perm(p), arg)
if let Some(ph) = self.unsafe_perm_vars.swap_remove(&p) { if !self.safe_perm_vars.contains(&p) => {
if ph == phase { if let Some(ph) = self.unsafe_perm_vars.swap_remove(&p) {
*query_instr = Instruction::PutUnsafeValue(p, arg); if ph == phase {
self.safe_perm_vars.insert(p); *query_instr = Instruction::PutUnsafeValue(p, arg);
} else { self.safe_perm_vars.insert(p);
self.unsafe_perm_vars.insert(p, ph); } else {
self.unsafe_perm_vars.insert(p, ph);
}
} }
} }
} &mut Instruction::SetValue(r @ RegType::Perm(p))
&mut Instruction::SetValue(r @ RegType::Perm(p)) if !self.safe_perm_vars.contains(&p) => { if !self.safe_perm_vars.contains(&p) => {
*query_instr = Instruction::SetLocalValue(r); *query_instr = Instruction::SetLocalValue(r);
self.safe_perm_vars.insert(p); self.safe_perm_vars.insert(p);
self.unsafe_perm_vars.remove(&p); self.unsafe_perm_vars.remove(&p);
} }
_ => {} _ => {}
} }
} }
fn mark_unsafe_temp_vars(&mut self, query_instr: &mut Instruction) { fn mark_unsafe_temp_vars(&mut self, query_instr: &mut Instruction) {
match query_instr { match query_instr {
&mut Instruction::SetValue(r @ RegType::Temp(t)) if !self.safe_temp_vars.contains(&t) => { &mut Instruction::SetValue(r @ RegType::Temp(t))
*query_instr = Instruction::SetLocalValue(r); if !self.safe_temp_vars.contains(&t) => {
*query_instr = Instruction::SetLocalValue(r);
self.safe_temp_vars.insert(t); self.safe_temp_vars.insert(t);
self.unsafe_temp_vars.remove(&t); self.unsafe_temp_vars.remove(&t);
} }
_ => { _ => {
} }
} }
@@ -360,6 +378,7 @@ impl UnsafeVarMarker {
fn clear_temp_vars(&mut self) { fn clear_temp_vars(&mut self) {
self.safe_temp_vars.clear(); self.safe_temp_vars.clear();
self.unsafe_temp_vars.clear(); self.unsafe_temp_vars.clear();
self.temp_vars_to_perm_vars.clear();
} }
pub(crate) fn mark_unsafe_instrs(&mut self, code: &mut Code) { pub(crate) fn mark_unsafe_instrs(&mut self, code: &mut Code) {
@@ -382,6 +401,7 @@ impl UnsafeVarMarker {
} }
while code_index < code.len() && !code[code_index].is_query_instr() { while code_index < code.len() && !code[code_index].is_query_instr() {
self.mark_safe_vars(&code[code_index]);
code_index += 1; code_index += 1;
} }