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fixed sierra gen revcation of const aliases #8526

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fixed sierra gen revcation of const aliases #8526

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77 changes: 58 additions & 19 deletions crates/cairo-lang-sierra-generator/src/local_variables.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -70,14 +70,13 @@ pub fn analyze_ap_changes<'db>(

let mut ctx = analysis.analyzer;
let peeled_used_after_revoke: OrderedHashSet<_> =
ctx.used_after_revoke.iter().map(|var| ctx.peel_aliases(var)).copied().collect();
ctx.used_after_revoke.iter().map(|var| ctx.peel_aliases(var).variable_id).collect();
// Any used after revoke variable that might be revoked should be a local.
let locals: OrderedHashSet<VariableId> = ctx
.used_after_revoke
.iter()
.filter(|var| ctx.might_be_revoked(&peeled_used_after_revoke, var))
.map(|var| ctx.peel_aliases(var))
.cloned()
.map(|var| ctx.peel_aliases(var).variable_id)
.collect();
let mut need_ap_alignment = OrderedHashSet::default();
if !root_info.known_ap_change {
Expand Down Expand Up @@ -115,6 +114,11 @@ struct CalledBlockInfo {
introduced_vars: Vec<VariableId>,
}

struct VarSource {
variable_id: VariableId,
allow_const: bool,
}

/// Context for the find_local_variables logic.
struct FindLocalsContext<'db, 'a> {
db: &'db dyn Database,
Expand All @@ -127,9 +131,9 @@ struct FindLocalsContext<'db, 'a> {
constants: UnorderedHashSet<VariableId>,
/// A mapping of variables which are the same in the context of finding locals.
/// I.e. if `aliases[var_id]` is local than var_id is also local.
aliases: UnorderedHashMap<VariableId, VariableId>,
aliases: UnorderedHashMap<VariableId, VarSource>,
/// A mapping from partial param variables to the containing variable.
partial_param_parents: UnorderedHashMap<VariableId, VariableId>,
partial_param_parents: UnorderedHashMap<VariableId, VarSource>,
}

pub type LoweredDemand = Demand<VariableId, ()>;
Expand Down Expand Up @@ -241,11 +245,13 @@ struct BranchInfo {

impl<'db, 'a> FindLocalsContext<'db, 'a> {
/// Given a variable that might be an alias follow aliases until we get the original variable.
pub fn peel_aliases(&'a self, mut var: &'a VariableId) -> &'a VariableId {
pub fn peel_aliases(&'a self, mut var: &'a VariableId) -> VarSource {
let mut allow_const = true;
while let Some(alias) = self.aliases.get(var) {
var = alias;
var = &alias.variable_id;
allow_const &= alias.allow_const;
}
var
VarSource { variable_id: *var, allow_const }
}

/// Return true if the variable might be revoked by ap changes.
Expand All @@ -258,19 +264,31 @@ impl<'db, 'a> FindLocalsContext<'db, 'a> {
peeled_used_after_revoke: &OrderedHashSet<VariableId>,
var: &VariableId,
) -> bool {
if self.constants.contains(var) {
let mut peeled = self.peel_aliases(var);
if self.constants.contains(&peeled.variable_id) {
return false;
}
let mut peeled = self.peel_aliases(var);
if self.non_ap_based.contains(peeled) {
if self.non_ap_based.contains(&peeled.variable_id) {
return false;
}
// In the case of partial params, we check if one of its ancestors is a local variable, or
// will be used after the revoke, and thus will be used as a local variable. If that
// is the case, then 'var' can not be revoked.
while let Some(parent) = self.partial_param_parents.get(peeled) {
peeled = self.peel_aliases(parent);
if self.non_ap_based.contains(peeled) || peeled_used_after_revoke.contains(peeled) {

let mut allow_const = peeled.allow_const;
while let Some(parent) = self.partial_param_parents.get(&peeled.variable_id) {
allow_const &= parent.allow_const;
peeled = self.peel_aliases(&parent.variable_id);
allow_const &= peeled.allow_const;
if self.non_ap_based.contains(&peeled.variable_id) {
return false;
}
// If the variable parent-peel chain ends in a const, but the allow_const flag is false
// (i.e. the chain went through a libfunc that doesn't allow consts),
// then the variable can be revoked as the saved const will be ap based.
if peeled_used_after_revoke.contains(&peeled.variable_id)
&& (!self.constants.contains(&peeled.variable_id) || allow_const)
{
return false;
}
}
Expand Down Expand Up @@ -309,10 +327,22 @@ impl<'db, 'a> FindLocalsContext<'db, 'a> {
for (var, output_info) in zip_eq(output_vars.iter(), var_output_infos.iter()) {
match output_info.ref_info {
OutputVarReferenceInfo::SameAsParam { param_idx } => {
self.aliases.insert(*var, input_vars[param_idx].var_id);
self.aliases.insert(
*var,
VarSource {
variable_id: input_vars[param_idx].var_id,
allow_const: _params_signatures[param_idx].allow_const,
},
);
}
OutputVarReferenceInfo::PartialParam { param_idx } => {
self.partial_param_parents.insert(*var, input_vars[param_idx].var_id);
self.partial_param_parents.insert(
*var,
VarSource {
variable_id: input_vars[param_idx].var_id,
allow_const: _params_signatures[param_idx].allow_const,
},
);
}
OutputVarReferenceInfo::Deferred(DeferredOutputKind::Const)
| OutputVarReferenceInfo::NewLocalVar
Expand Down Expand Up @@ -387,12 +417,21 @@ impl<'db, 'a> FindLocalsContext<'db, 'a> {
)
}
lowering::Statement::Snapshot(statement_snapshot) => {
self.aliases.insert(statement_snapshot.original(), statement_snapshot.input.var_id);
self.aliases.insert(statement_snapshot.snapshot(), statement_snapshot.input.var_id);
self.aliases.insert(
statement_snapshot.original(),
VarSource { variable_id: statement_snapshot.input.var_id, allow_const: true },
);
self.aliases.insert(
statement_snapshot.snapshot(),
VarSource { variable_id: statement_snapshot.input.var_id, allow_const: true },
);
BranchInfo { known_ap_change: true }
}
lowering::Statement::Desnap(statement_desnap) => {
self.aliases.insert(statement_desnap.output, statement_desnap.input.var_id);
self.aliases.insert(
statement_desnap.output,
VarSource { variable_id: statement_desnap.input.var_id, allow_const: true },
);
BranchInfo { known_ap_change: true }
}
};
Expand Down
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