improvement(semantic/cfg): better control flow for switch statements.

Author: rzvxa

crates/oxc_semantic/src/builder.rs

@@ -1069,12 +1069,13 @@ impl<'a> Visit<'a> for SemanticBuilder<'a> {
             );
         }
 
-        if let Some(last) = switch_case_conditions.last() {
-            self.cfg.add_edge(*last, self.cfg.current_node_ix, EdgeType::Normal);
+        let end_of_switch_case_statement = self.cfg.new_basic_block_normal();
+
+        if let Some(last) = ends_of_switch_cases.last() {
+            self.cfg.add_edge(*last, end_of_switch_case_statement, EdgeType::Normal);
         }
 
-        let current_node_ix = self.cfg.current_node_ix;
-        self.cfg.ctx(None).mark_break(current_node_ix).resolve();
+        self.cfg.ctx(None).mark_break(end_of_switch_case_statement).resolve();
         /* cfg */
 
         self.leave_scope();

crates/oxc_semantic/tests/integration/snapshots/integration__cfg__cfg_files@switch_in_while.js-2.snap

@@ -14,6 +14,7 @@ digraph {
     7 [ label = "" ]
     8 [ label = "ExpressionStatement" ]
     9 [ label = "" ]
+    10 [ label = "" ]
     1 -> 0 [ label = "Error(Implicit)" ]
     2 -> 0 [ label = "Error(Implicit)" ]
     3 -> 0 [ label = "Error(Implicit)" ]
@@ -29,8 +30,9 @@ digraph {
     6 -> 7 [ label = "Normal" ]
     3 -> 4 [ label = "Normal" ]
     3 -> 7 [ label = "Normal" ]
-    7 -> 8 [ label = "Normal" ]
     9 -> 0 [ label = "Error(Implicit)" ]
+    8 -> 9 [ label = "Normal" ]
+    10 -> 0 [ label = "Error(Implicit)" ]
     1 -> 2 [ label = "Normal" ]
     2 -> 3 [ label = "Normal" ]
     8 -> 2 [ label = "Backedge" ]

crates/oxc_semantic/tests/integration/snapshots/integration__cfg__cfg_files@switch_in_while.js.snap

@@ -44,3 +44,7 @@ bb8: {
 bb9: {
 
 }
+
+bb10: {
+
+}

crates/oxc_semantic/tests/integration/snapshots/integration__cfg__cfg_files@switch_statement.js-2.snap

@@ -23,9 +23,10 @@ digraph {
     16 [ label = "ExpressionStatement\nExpressionStatement\nExpressionStatement" ]
     17 [ label = "" ]
     18 [ label = "ExpressionStatement\nreturn <value>" ]
-    19 [ label = "unreachable\nExpressionStatement\nreturn <value>" ]
-    20 [ label = "unreachable" ]
-    21 [ label = "" ]
+    19 [ label = "unreachable" ]
+    20 [ label = "ExpressionStatement\nreturn <value>" ]
+    21 [ label = "unreachable" ]
+    22 [ label = "" ]
     1 -> 0 [ label = "Error(Implicit)" ]
     3 -> 2 [ label = "Error(Implicit)" ]
     1 -> 3 [ label = "NewFunction" ]
@@ -81,11 +82,12 @@ digraph {
     16 -> 17 [ label = "Normal" ]
     3 -> 15 [ label = "Normal" ]
     3 -> 17 [ label = "Normal" ]
-    17 -> 19 [ label = "Normal" ]
-    5 -> 19 [ label = "Jump" ]
-    10 -> 19 [ label = "Jump" ]
     20 -> 2 [ label = "Error(Implicit)" ]
-    19 -> 20 [ label = "Unreachable" , style = "dotted" ]
-    21 -> 0 [ label = "Error(Implicit)" ]
-    1 -> 21 [ label = "Normal" ]
+    19 -> 20 [ label = "Normal" ]
+    5 -> 20 [ label = "Jump" ]
+    10 -> 20 [ label = "Jump" ]
+    21 -> 2 [ label = "Error(Implicit)" ]
+    20 -> 21 [ label = "Unreachable" , style = "dotted" ]
+    22 -> 0 [ label = "Error(Implicit)" ]
+    1 -> 22 [ label = "Normal" ]
 }

crates/oxc_semantic/tests/integration/snapshots/integration__cfg__cfg_files@switch_statement.js.snap

@@ -90,14 +90,17 @@ bb18: {
 
 bb19: {
 	unreachable
+}
+
+bb20: {
 	statement
 	return <value>
 }
 
-bb20: {
+bb21: {
 	unreachable
 }
 
-bb21: {
+bb22: {
 
 }