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[rust][sema] Bubble unresolved references (for hoisting)

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This is a precursor to adding support for hoisting in semantic analysis. 
Previously when we encountered an unknown reference we immediately reported an 
error. But hoisted variables may be referenced before they're defined, so we 
don't know for sure when we see an unknown variable if its actually unbound or 
not. 

This PR adds the first part of hoistingn support: rather than immediately report 
an error when encountering an unbound variable we store it in a list of 
unresolved references on the current scope. As we close each scope we recheck 
and see if the variable can now be resolved. If yes we record that, otherwise we 
bubble up the unresolved reference to the parent scope (and try again there). 

The next PR(s) will handle hoisting of `var` and other syntax to the apropriate 
nearest scope boundary (function/module).
This commit is contained in:
Joe Savona
2023-08-14 10:08:02 -07:00
parent 57f648009c
commit 011570a078
4 changed files with 221 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
compiler/forget/crates/forget_semantic_analysis/src/analyzer.rs
+48 -11
View File
@@ -86,10 +86,9 @@ impl Analyzer {
where
F: FnMut(&mut Self) -> (),
{
let scope = self.manager.add_scope(self.current, kind);
let previous = std::mem::replace(&mut self.current, scope);
let scope = self.enter_scope(kind);
f(self);
let scope = std::mem::replace(&mut self.current, previous);
self.close_scope(scope);
scope
}
@@ -101,8 +100,26 @@ impl Analyzer {
fn close_scope(&mut self, id: ScopeId) {
assert_eq!(self.current, id, "Mismatched enter_scope/close_scope");
let scope = self.manager.scope(self.current);
self.current = scope.parent.unwrap();
let scope = self.manager.mut_scope(self.current);
let parent = scope.parent.unwrap();
let unresolved = std::mem::take(&mut scope.unresolved);
drop(scope);
self.current = parent;
// Lookup unresolved nodes from the child scope in the (now-current) parent scope
for reference in unresolved {
if let Some(declaration) = self
.manager
.lookup_declaration(reference.scope, &reference.name)
{
let id =
self.manager
.add_reference(reference.scope, reference.kind, declaration.id);
self.manager.node_references.insert(reference.ast, id);
} else {
self.manager.push_unresolved_reference(parent, reference);
}
}
}
fn visit_function<T: IntoFunction>(&mut self, node: &T) {
@@ -157,10 +174,8 @@ impl Analyzer {
.add_reference(self.current, kind, declaration.id);
self.manager.node_references.insert(ast, id);
} else {
// Oops, undefined variable
self.manager
.diagnostics
.push(Diagnostic::invalid_syntax("Undefined variable", range));
.add_unresolved_reference(self.current, ast, name.to_string(), kind, range);
}
}
@@ -201,9 +216,13 @@ impl Analyzer {
.node_references
.insert(AstNode::from(ast), reference);
} else {
self.manager
.diagnostics
.push(Diagnostic::invalid_syntax("Undefined variable", ast.range));
self.manager.add_unresolved_reference(
self.current,
AstNode::from(ast),
ast.name.clone(),
ReferenceKind::ReadWrite,
ast.range,
);
}
}
}
@@ -616,6 +635,24 @@ impl Visitor for Analyzer {
self.visit_module_item(item);
}
}
let scope = self.manager.mut_scope(self.current);
let unresolved = std::mem::take(&mut scope.unresolved);
for reference in unresolved {
if let Some(declaration) = self
.manager
.lookup_declaration(reference.scope, &reference.name)
{
let id =
self.manager
.add_reference(reference.scope, reference.kind, declaration.id);
self.manager.node_references.insert(reference.ast, id);
} else {
self.manager.diagnostics.push(Diagnostic::invalid_syntax(
"Undefined variable",
reference.range,
));
}
}
}
fn visit_property(&mut self, ast: &forget_estree::Property) {
compiler/forget/crates/forget_semantic_analysis/src/scope_manager.rs
+43 -1
View File
@@ -1,6 +1,7 @@
use forget_diagnostics::Diagnostic;
use forget_estree::{
BreakStatement, ContinueStatement, ESTreeNode, LabeledStatement, VariableDeclarationKind,
BreakStatement, ContinueStatement, ESTreeNode, LabeledStatement, SourceRange,
VariableDeclarationKind,
};
use forget_utils::PointerAddress;
use indexmap::IndexMap;
@@ -43,6 +44,7 @@ impl ScopeManager {
declarations: Default::default(),
references: Default::default(),
children: Default::default(),
unresolved: Default::default(),
}],
labels: Default::default(),
declarations: Default::default(),
@@ -75,6 +77,10 @@ impl ScopeManager {
&self.scopes[id.0]
}
pub fn mut_scope(&mut self, id: ScopeId) -> &mut Scope {
&mut self.scopes[id.0]
}
pub fn is_descendant_of(&self, maybe_descendant: ScopeId, maybe_ancestor: ScopeId) -> bool {
let mut current = maybe_descendant;
loop {
@@ -192,6 +198,7 @@ impl ScopeManager {
declarations: Default::default(),
references: Default::default(),
children: Default::default(),
unresolved: Default::default(),
});
self.scopes[parent.0].children.push(id);
id
@@ -252,6 +259,31 @@ impl ScopeManager {
self.scopes[scope.0].references.push(id);
id
}
pub(crate) fn push_unresolved_reference(
&mut self,
scope: ScopeId,
reference: UnresolvedReference,
) {
self.scopes[scope.0].unresolved.push(reference);
}
pub(crate) fn add_unresolved_reference(
&mut self,
scope: ScopeId,
ast: AstNode,
name: String,
kind: ReferenceKind,
range: Option<SourceRange>,
) {
self.scopes[scope.0].unresolved.push(UnresolvedReference {
ast,
scope,
name,
kind,
range,
});
}
}
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Clone)]
@@ -286,6 +318,16 @@ pub struct Scope {
pub declarations: IndexMap<String, DeclarationId>,
pub references: Vec<ReferenceId>,
pub children: Vec<ScopeId>,
pub unresolved: Vec<UnresolvedReference>,
}
#[derive(Debug, Clone)]
pub struct UnresolvedReference {
pub scope: ScopeId,
pub ast: AstNode,
pub name: String,
pub kind: ReferenceKind,
pub range: Option<SourceRange>,
}
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Clone)]
compiler/forget/crates/forget_semantic_analysis/tests/fixtures/let-const-hoisting.js
Vendored
+8
View File
@@ -0,0 +1,8 @@
function Component() {
function foo() {
a;
b;
}
let a;
const b = true;
}
compiler/forget/crates/forget_semantic_analysis/tests/snapshots/analysis_test__fixtures@let-const-hoisting.js.snap
+122
View File
@@ -0,0 +1,122 @@
---
source: crates/forget_semantic_analysis/tests/analysis_test.rs
expression: "format!(\"Input:\\n{input}\\n\\nAnalysis:\\n{output}\")"
input_file: crates/forget_semantic_analysis/tests/fixtures/let-const-hoisting.js
---
Input:
function Component() {
function foo() {
a;
b;
}
let a;
const b = true;
}
Analysis:
Scope {
id: ScopeId(
0,
),
kind: Global,
declarations: {},
references: [],
children: [
Scope {
id: ScopeId(
1,
),
kind: Module,
declarations: {
"Component": Declaration {
id: DeclarationId(
0,
),
kind: FunctionDeclaration,
scope: ScopeId(
1,
),
},
},
references: [],
children: [
Scope {
id: ScopeId(
2,
),
kind: Function,
declarations: {
"foo": Declaration {
id: DeclarationId(
1,
),
kind: FunctionDeclaration,
scope: ScopeId(
2,
),
},
"a": Declaration {
id: DeclarationId(
2,
),
kind: Let,
scope: ScopeId(
2,
),
},
"b": Declaration {
id: DeclarationId(
3,
),
kind: Const,
scope: ScopeId(
2,
),
},
},
references: [],
children: [
Scope {
id: ScopeId(
3,
),
kind: Function,
declarations: {},
references: [
Reference {
id: ReferenceId(
0,
),
kind: Read,
declaration: DeclarationId(
2,
),
declaration (name): "a",
scope: ScopeId(
3,
),
},
Reference {
id: ReferenceId(
1,
),
kind: Read,
declaration: DeclarationId(
3,
),
declaration (name): "b",
scope: ScopeId(
3,
),
},
],
children: [],
},
],
},
],
},
],
}