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refactor(minifier): clean up has_no_side_effect_for_evaluation_same_target (#8675)

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Boshen 2025-01-23 12:52:48 +00:00 committed by Boshen
parent 3fa87ff6a6
commit 75a579b619
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2 changed files with 23 additions and 25 deletions
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2
crates/oxc_minifier/src/peephole/fold_constants.rs
View file

@ -673,6 +673,7 @@ impl<'a, 'b> PeepholeOptimizations {
| "undefined" | "undefined"
| "object" | "object"
| "function" | "function"
| "unknown" // IE
) { ) {
return Some(ctx.ast.expression_boolean_literal( return Some(ctx.ast.expression_boolean_literal(
bin_expr.span, bin_expr.span,
@ -1032,6 +1033,7 @@ mod test {
test("'a' == 'a'", "!0"); test("'a' == 'a'", "!0");
test("'b' != 'a'", "!0"); test("'b' != 'a'", "!0");
test_same("typeof a != 'number'"); test_same("typeof a != 'number'");
test_same("typeof a != 'unknown'"); // IE
test("'a' === 'a'", "!0"); test("'a' === 'a'", "!0");
test("'b' !== 'a'", "!0"); test("'b' !== 'a'", "!0");
test_same("'' + x <= '' + y"); test_same("'' + x <= '' + y");

46
crates/oxc_minifier/src/peephole/minimize_conditions.rs
View file

@ -1075,16 +1075,13 @@ impl<'a> PeepholeOptimizations {
if self.target < ESTarget::ES2020 { if self.target < ESTarget::ES2020 {
return None; return None;
} }
let Expression::AssignmentExpression(assignment_expr) = &mut expr.right else { let Expression::AssignmentExpression(assignment_expr) = &mut expr.right else {
return None; return None;
}; };
if assignment_expr.operator != AssignmentOperator::Assign { if assignment_expr.operator != AssignmentOperator::Assign {
return None; return None;
} }
let new_op = expr.operator.to_assignment_operator(); let new_op = expr.operator.to_assignment_operator();
if !Self::has_no_side_effect_for_evaluation_same_target( if !Self::has_no_side_effect_for_evaluation_same_target(
&assignment_expr.left, &assignment_expr.left,
&expr.left, &expr.left,
@ -1092,7 +1089,6 @@ impl<'a> PeepholeOptimizations {
) { ) {
return None; return None;
} }
assignment_expr.span = expr.span; assignment_expr.span = expr.span;
assignment_expr.operator = new_op; assignment_expr.operator = new_op;
Some(ctx.ast.move_expression(&mut expr.right)) Some(ctx.ast.move_expression(&mut expr.right))
@ -1129,37 +1125,36 @@ impl<'a> PeepholeOptimizations {
/// ///
/// - `a`, `a` /// - `a`, `a`
/// - `a.b`, `a.b` /// - `a.b`, `a.b`
/// - `a.#b`, `a.#b` /// - `a["b"]`, `a["b"]`
fn has_no_side_effect_for_evaluation_same_target( fn has_no_side_effect_for_evaluation_same_target(
assignment_target: &AssignmentTarget, assignment_target: &AssignmentTarget,
expr: &Expression, expr: &Expression,
ctx: &mut TraverseCtx<'a>, ctx: &mut TraverseCtx<'a>,
) -> bool { ) -> bool {
match (&assignment_target, &expr) { if let (
( AssignmentTarget::AssignmentTargetIdentifier(write_id_ref),
AssignmentTarget::AssignmentTargetIdentifier(write_id_ref), Expression::Identifier(read_id_ref),
Expression::Identifier(read_id_ref), ) = (assignment_target, expr)
) => write_id_ref.name == read_id_ref.name, {
( return write_id_ref.name == read_id_ref.name;
AssignmentTarget::StaticMemberExpression(_), }
Expression::StaticMemberExpression(_), if let Some(write_expr) = assignment_target.as_member_expression() {
) if let MemberExpression::ComputedMemberExpression(e) = write_expr {
| ( if !matches!(e.expression, Expression::StringLiteral(_)) {
AssignmentTarget::PrivateFieldExpression(_),
Expression::PrivateFieldExpression(_),
) => {
let write_expr = assignment_target.to_member_expression();
let read_expr = expr.to_member_expression();
let Expression::Identifier(write_expr_object_id) = &write_expr.object() else {
return false; return false;
}; }
}
let Expression::Identifier(write_expr_object_id) = &write_expr.object() else {
return false;
};
if let Some(read_expr) = expr.as_member_expression() {
// It should also return false when the reference might refer to a reference value created by a with statement // It should also return false when the reference might refer to a reference value created by a with statement
// when the minifier supports with statements // when the minifier supports with statements
!Ctx(ctx).is_global_reference(write_expr_object_id) return !Ctx(ctx).is_global_reference(write_expr_object_id)
&& write_expr.content_eq(read_expr) && write_expr.content_eq(read_expr);
} }
_ => false,
} }
false
} }
/// Compress `a = a + b` to `a += b` /// Compress `a = a + b` to `a += b`
@ -2475,6 +2470,7 @@ mod test {
// GetValue(x) has no sideeffect when x is a resolved identifier // GetValue(x) has no sideeffect when x is a resolved identifier
test("var x; x.y || (x.y = 3)", "var x; x.y ||= 3"); test("var x; x.y || (x.y = 3)", "var x; x.y ||= 3");
test("var x; x['y'] || (x['y'] = 3)", "var x; x.y ||= 3");
test("var x; x.#y || (x.#y = 3)", "var x; x.#y ||= 3"); test("var x; x.#y || (x.#y = 3)", "var x; x.#y ||= 3");
test_same("x.y || (x.y = 3)"); test_same("x.y || (x.y = 3)");
// this can be compressed if `y` does not have side effect // this can be compressed if `y` does not have side effect