fix(oxc_semantic): Handle short-circuiting operators in CFG (#2252)

Closes #2239

crates/oxc_semantic/src/builder.rs

@@ -666,6 +666,73 @@ impl<'a> Visit<'a> for SemanticBuilder<'a> {
         self.leave_node(kind);
     }
 
+    fn visit_logical_expression(&mut self, expr: &LogicalExpression<'a>) {
+        // logical expressions are short-circuiting, and therefore
+        // also represent control flow.
+        // For example, in:
+        //   foo && bar();
+        // the bar() call will only be executed if foo is truthy.
+        let kind = AstKind::LogicalExpression(self.alloc(expr));
+        self.enter_node(kind);
+
+        self.visit_expression(&expr.left);
+
+        /* cfg  */
+        let left_expr_end_ix = self.cfg.current_node_ix;
+        let right_expr_start_ix = self.cfg.new_basic_block();
+        /* cfg  */
+
+        self.visit_expression(&expr.right);
+
+        /* cfg */
+        let right_expr_end_ix = self.cfg.current_node_ix;
+        let after_logical_expr_ix = self.cfg.new_basic_block();
+
+        self.cfg.add_edge(left_expr_end_ix, right_expr_start_ix, EdgeType::Normal);
+        self.cfg.add_edge(left_expr_end_ix, after_logical_expr_ix, EdgeType::Normal);
+        self.cfg.add_edge(right_expr_end_ix, after_logical_expr_ix, EdgeType::Normal);
+        /* cfg */
+
+        self.leave_node(kind);
+    }
+
+    fn visit_assignment_expression(&mut self, expr: &AssignmentExpression<'a>) {
+        // assignment expressions can include an operator, which
+        // can be used to determine the control flow of the expression.
+        // For example, in:
+        //   foo &&= super();
+        // the super() call will only be executed if foo is truthy.
+
+        let kind = AstKind::AssignmentExpression(self.alloc(expr));
+        self.enter_node(kind);
+        self.visit_assignment_target(&expr.left);
+
+        /* cfg  */
+        let cfg_ixs = if expr.operator.is_logical() {
+            let target_end_ix = self.cfg.current_node_ix;
+            let expr_start_ix = self.cfg.new_basic_block();
+            Some((target_end_ix, expr_start_ix))
+        } else {
+            None
+        };
+        /* cfg  */
+
+        self.visit_expression(&expr.right);
+
+        /* cfg */
+        if let Some((target_end_ix, expr_start_ix)) = cfg_ixs {
+            let expr_end_ix = self.cfg.current_node_ix;
+            let after_assignment_ix = self.cfg.new_basic_block();
+
+            self.cfg.add_edge(target_end_ix, expr_start_ix, EdgeType::Normal);
+            self.cfg.add_edge(target_end_ix, after_assignment_ix, EdgeType::Normal);
+            self.cfg.add_edge(expr_end_ix, after_assignment_ix, EdgeType::Normal);
+        }
+        /* cfg */
+
+        self.leave_node(kind);
+    }
+
     fn visit_for_statement(&mut self, stmt: &ForStatement<'a>) {
         let kind = AstKind::ForStatement(self.alloc(stmt));
         let is_lexical_declaration =

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@assignment_operators.js-2.snap

@@ -5,5 +5,20 @@ input_file: crates/oxc_semantic/tests/cfg_fixtures/assignment_operators.js
 ---
 digraph {
     0 [ label = ""]
+    1 [ label = ""]
+    2 [ label = ""]
+    3 [ label = ""]
+    4 [ label = ""]
+    5 [ label = ""]
+    6 [ label = ""]
+    0 -> 1 [ ]
+    0 -> 2 [ ]
+    1 -> 2 [ ]
+    2 -> 3 [ ]
+    2 -> 4 [ ]
+    3 -> 4 [ ]
+    4 -> 5 [ ]
+    4 -> 6 [ ]
+    5 -> 6 [ ]
 }
 

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@assignment_operators.js.snap

@@ -6,3 +6,27 @@ input_file: crates/oxc_semantic/tests/cfg_fixtures/assignment_operators.js
 bb0: {
 
 }
+
+bb1: {
+
+}
+
+bb2: {
+
+}
+
+bb3: {
+
+}
+
+bb4: {
+
+}
+
+bb5: {
+
+}
+
+bb6: {
+
+}

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@function_as_expression.js-2.snap

@@ -27,6 +27,10 @@ digraph {
     20 [ label = ""]
     21 [ label = ""]
     22 [ label = ""]
+    23 [ label = ""]
+    24 [ label = ""]
+    25 [ label = ""]
+    26 [ label = ""]
     0 -> 1 [ ]
     0 -> 2 [ ]
     2 -> 3 [ ]
@@ -45,9 +49,15 @@ digraph {
     14 -> 16 [ ]
     16 -> 17 [ ]
     16 -> 18 [ ]
+    17 -> 18 [ ]
     18 -> 19 [ ]
     18 -> 20 [ ]
     20 -> 21 [ ]
     20 -> 22 [ ]
+    21 -> 22 [ ]
+    22 -> 23 [ ]
+    22 -> 24 [ ]
+    24 -> 25 [ ]
+    24 -> 26 [ ]
 }
 

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@function_as_expression.js.snap

@@ -94,3 +94,19 @@ bb21: {
 bb22: {
 
 }
+
+bb23: {
+
+}
+
+bb24: {
+
+}
+
+bb25: {
+
+}
+
+bb26: {
+
+}

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@if_else.js-2.snap

@@ -6,26 +6,31 @@ input_file: crates/oxc_semantic/tests/cfg_fixtures/if_else.js
 digraph {
     0 [ label = ""]
     1 [ label = ""]
-    2 [ label = "$return = <value>"]
+    2 [ label = ""]
     3 [ label = ""]
-    4 [ label = "Unreachable()"]
+    4 [ label = "$return = <value>"]
-    5 [ label = "$return = <value>"]
+    5 [ label = ""]
-    6 [ label = ""]
+    6 [ label = "Unreachable()"]
-    7 [ label = "Unreachable()"]
+    7 [ label = "$return = <value>"]
     8 [ label = ""]
-    9 [ label = "Unreachable()\n$return = <value>"]
+    9 [ label = "Unreachable()"]
     10 [ label = ""]
-    11 [ label = "Unreachable()"]
+    11 [ label = "Unreachable()\n$return = <value>"]
     12 [ label = ""]
+    13 [ label = "Unreachable()"]
+    14 [ label = ""]
     0 -> 1 [ ]
-    3 -> 4 [ ]
-    6 -> 7 [ ]
-    8 -> 9 [ ]
-    4 -> 8 [ ]
     1 -> 2 [ ]
-    1 -> 5 [ ]
+    1 -> 3 [ ]
-    7 -> 8 [ ]
+    2 -> 3 [ ]
+    5 -> 6 [ ]
+    8 -> 9 [ ]
     10 -> 11 [ ]
-    0 -> 12 [ ]
+    6 -> 10 [ ]
+    3 -> 4 [ ]
+    3 -> 7 [ ]
+    9 -> 10 [ ]
+    12 -> 13 [ ]
+    0 -> 14 [ ]
 }
 

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@if_else.js.snap

@@ -12,7 +12,7 @@ bb1: {
 }
 
 bb2: {
-	$return = <value>
+
 }
 
 bb3: {
@@ -20,28 +20,27 @@ bb3: {
 }
 
 bb4: {
-	Unreachable()
-}
-
-bb5: {
 	$return = <value>
 }
 
-bb6: {
+bb5: {
 
 }
 
-bb7: {
+bb6: {
 	Unreachable()
 }
 
+bb7: {
+	$return = <value>
+}
+
 bb8: {
 
 }
 
 bb9: {
 	Unreachable()
-	$return = <value>
 }
 
 bb10: {
@@ -50,8 +49,17 @@ bb10: {
 
 bb11: {
 	Unreachable()
+	$return = <value>
 }
 
 bb12: {
 
 }
+
+bb13: {
+	Unreachable()
+}
+
+bb14: {
+
+}

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@infix_operators.js-2.snap

@@ -5,5 +5,10 @@ input_file: crates/oxc_semantic/tests/cfg_fixtures/infix_operators.js
 ---
 digraph {
     0 [ label = ""]
+    1 [ label = ""]
+    2 [ label = ""]
+    0 -> 1 [ ]
+    0 -> 2 [ ]
+    1 -> 2 [ ]
 }
 

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@infix_operators.js.snap

@@ -6,3 +6,11 @@ input_file: crates/oxc_semantic/tests/cfg_fixtures/infix_operators.js
 bb0: {
 
 }
+
+bb1: {
+
+}
+
+bb2: {
+
+}

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@logical_expressions_short_circuit.js-2.snap

@@ -11,14 +11,29 @@ digraph {
     4 [ label = ""]
     5 [ label = ""]
     6 [ label = ""]
-    1 -> 2 [ ]
+    7 [ label = ""]
+    8 [ label = ""]
+    9 [ label = ""]
+    10 [ label = ""]
+    11 [ label = ""]
+    12 [ label = ""]
     0 -> 1 [ ]
     0 -> 2 [ ]
+    1 -> 2 [ ]
     3 -> 4 [ ]
     2 -> 3 [ ]
     2 -> 4 [ ]
-    5 -> 6 [ ]
     4 -> 5 [ ]
     4 -> 6 [ ]
+    5 -> 6 [ ]
+    7 -> 8 [ ]
+    6 -> 7 [ ]
+    6 -> 8 [ ]
+    8 -> 9 [ ]
+    8 -> 10 [ ]
+    9 -> 10 [ ]
+    11 -> 12 [ ]
+    10 -> 11 [ ]
+    10 -> 12 [ ]
 }
 

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@logical_expressions_short_circuit.js.snap

@@ -30,3 +30,27 @@ bb5: {
 bb6: {
 
 }
+
+bb7: {
+
+}
+
+bb8: {
+
+}
+
+bb9: {
+
+}
+
+bb10: {
+
+}
+
+bb11: {
+
+}
+
+bb12: {
+
+}

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@while.js-2.snap

@@ -7,21 +7,26 @@ digraph {
     0 [ label = ""]
     1 [ label = ""]
     2 [ label = ""]
-    3 [ label = "$return = <value>"]
+    3 [ label = ""]
     4 [ label = ""]
-    5 [ label = "Unreachable()"]
+    5 [ label = "$return = <value>"]
-    6 [ label = "$return = <value>"]
+    6 [ label = ""]
-    7 [ label = ""]
+    7 [ label = "Unreachable()"]
-    8 [ label = "Unreachable()"]
+    8 [ label = "$return = <value>"]
     9 [ label = ""]
+    10 [ label = "Unreachable()"]
+    11 [ label = ""]
     0 -> 1 [ ]
-    4 -> 5 [ ]
-    1 -> 2 [ ]
     2 -> 3 [ ]
-    3 -> 6 [ ]
+    2 -> 4 [ ]
-    3 -> 2 [ ]
+    3 -> 4 [ ]
-    2 -> 6 [ ]
+    6 -> 7 [ ]
-    7 -> 8 [ ]
+    1 -> 2 [ ]
-    0 -> 9 [ ]
+    2 -> 5 [ ]
+    5 -> 8 [ ]
+    5 -> 2 [ ]
+    2 -> 8 [ ]
+    9 -> 10 [ ]
+    0 -> 11 [ ]
 }
 

crates/oxc_semantic/tests/snapshots/cfg__cfg_files@while.js.snap

@@ -16,7 +16,7 @@ bb2: {
 }
 
 bb3: {
-	$return = <value>
+
 }
 
 bb4: {
@@ -24,21 +24,29 @@ bb4: {
 }
 
 bb5: {
-	Unreachable()
-}
-
-bb6: {
 	$return = <value>
 }
 
-bb7: {
+bb6: {
 
 }
 
-bb8: {
+bb7: {
 	Unreachable()
 }
 
+bb8: {
+	$return = <value>
+}
+
 bb9: {
 
 }
+
+bb10: {
+	Unreachable()
+}
+
+bb11: {
+
+}