JS: Emit variables for 'this'

javascript/downgrades/26a123164be893893e2aa0374d820785decf55af/upgrade.properties

@@ -0,0 +1,2 @@
+description: Add variable bindings for 'this'
+compatibility: partial

javascript/extractor/src/com/semmle/js/extractor/ASTExtractor.java

@@ -819,6 +819,7 @@ public Label visit(Program nd, Context c) {
       // add all declared global (or module-scoped) names, both non-lexical and lexical
       scopeManager.addNames(scopeManager.collectDeclaredNames(nd, isStrict, false, DeclKind.none));
       scopeManager.addNames(scopeManager.collectDeclaredNames(nd, isStrict, true, DeclKind.none));
+      scopeManager.addVariables("this");
 
       visitAll(nd.getBody(), toplevelLabel);
 
@@ -1070,6 +1071,9 @@ private void extractFunction(IFunction nd, Label key) {
 
       scopeManager.enterScope((Node) nd);
       scopeManager.addNames(locals);
+      if (!(nd instanceof ArrowFunctionExpression)) {
+        scopeManager.addVariables("this");
+      }
 
       // The name of a function expression binds to its own scope.
       if (nd.getId() != null && nd instanceof AFunctionExpression) {
@@ -1541,8 +1545,9 @@ private Label visit(AClass ac, Label key, Node scopeNode, boolean isClassExpress
       if (!isClassExpression) {
         visit(ac.getId(), key, 0, IdContext.VAR_AND_TYPE_DECL);
       }
+      scopeManager.enterScope(scopeNode);
+      scopeManager.addVariables("this"); // 'this' in static field initialiers refers to the class
       if (ac.hasId() || ac.hasTypeParameters()) {
-        scopeManager.enterScope(scopeNode);
         if (isClassExpression && ac.hasId()) {
           scopeManager.addVariables(ac.getId().getName());
           scopeManager.addTypeName(ac.getId().getName());
@@ -1565,9 +1570,7 @@ private Label visit(AClass ac, Label key, Node scopeNode, boolean isClassExpress
         addDefaultConstructor(ac);
       }
       visit(ac.getBody(), key, 2);
-      if (ac.hasId() || ac.hasTypeParameters()) {
-        scopeManager.leaveScope();
-      }
+      scopeManager.leaveScope();
       emitNodeSymbol(ac, key);
       return key;
     }
@@ -1893,6 +1896,15 @@ public Label visit(JSXThisExpr nd, Context c) {
       return visit((ThisExpression) nd, c);
     }
 
+    @Override
+    public Label visit(ThisExpression nd, Context c) {
+      Label key = super.visit(nd, c);
+      if (c.idcontext == IdContext.VAR_BIND || c.idcontext == IdContext.VAR_IN_TYPE_BIND) {
+        addVariableBinding("bind", key, "this");
+      }
+      return key;
+    }
+
     @Override
     public Label visit(JSXMemberExpression nd, Context c) {
       Label key = super.visit(nd, c);

javascript/extractor/tests/cfg/output/trap/classexpr1.js.trap

@@ -47,74 +47,84 @@ locations_default(#20015,#10000,1,11,1,10)
 hasLocation(#20014,#20015)
 toplevels(#20001,0)
 hasLocation(#20001,#20003)
-#20016=*
-stmts(#20016,2,#20001,0,"!class {};")
-hasLocation(#20016,#20003)
-stmt_containers(#20016,#20001)
+#20016=@"var;{this};{#20000}"
+variables(#20016,"this",#20000)
 #20017=*
-exprs(#20017,18,#20016,0,"!class {}")
-#20018=@"loc,{#10000},1,1,1,9"
-locations_default(#20018,#10000,1,1,1,9)
-hasLocation(#20017,#20018)
-enclosing_stmt(#20017,#20016)
-expr_containers(#20017,#20001)
-#20019=*
-exprs(#20019,80,#20017,0,"class {}")
-#20020=@"loc,{#10000},1,2,1,9"
-locations_default(#20020,#10000,1,2,1,9)
-hasLocation(#20019,#20020)
-enclosing_stmt(#20019,#20016)
-expr_containers(#20019,#20001)
-#20021=*
-properties(#20021,#20019,2,0,"constructor() {}")
-#20022=@"loc,{#10000},1,8,1,7"
-locations_default(#20022,#10000,1,8,1,7)
-hasLocation(#20021,#20022)
-#20023=*
-exprs(#20023,0,#20021,0,"constructor")
-hasLocation(#20023,#20022)
-enclosing_stmt(#20023,#20016)
-expr_containers(#20023,#20001)
-literals("constructor","constructor",#20023)
+stmts(#20017,2,#20001,0,"!class {};")
+hasLocation(#20017,#20003)
+stmt_containers(#20017,#20001)
+#20018=*
+exprs(#20018,18,#20017,0,"!class {}")
+#20019=@"loc,{#10000},1,1,1,9"
+locations_default(#20019,#10000,1,1,1,9)
+hasLocation(#20018,#20019)
+enclosing_stmt(#20018,#20017)
+expr_containers(#20018,#20001)
+#20020=*
+exprs(#20020,80,#20018,0,"class {}")
+#20021=@"loc,{#10000},1,2,1,9"
+locations_default(#20021,#10000,1,2,1,9)
+hasLocation(#20020,#20021)
+enclosing_stmt(#20020,#20017)
+expr_containers(#20020,#20001)
+#20022=*
+scopes(#20022,8)
+scopenodes(#20020,#20022)
+scopenesting(#20022,#20000)
+#20023=@"var;{this};{#20022}"
+variables(#20023,"this",#20022)
 #20024=*
-exprs(#20024,9,#20021,1,"() {}")
-hasLocation(#20024,#20022)
-enclosing_stmt(#20024,#20016)
-expr_containers(#20024,#20001)
-#20025=*
-scopes(#20025,1)
-scopenodes(#20024,#20025)
-scopenesting(#20025,#20000)
-#20026=@"var;{arguments};{#20025}"
-variables(#20026,"arguments",#20025)
-is_arguments_object(#20026)
+properties(#20024,#20020,2,0,"constructor() {}")
+#20025=@"loc,{#10000},1,8,1,7"
+locations_default(#20025,#10000,1,8,1,7)
+hasLocation(#20024,#20025)
+#20026=*
+exprs(#20026,0,#20024,0,"constructor")
+hasLocation(#20026,#20025)
+enclosing_stmt(#20026,#20017)
+expr_containers(#20026,#20001)
+literals("constructor","constructor",#20026)
 #20027=*
-stmts(#20027,1,#20024,-2,"{}")
-hasLocation(#20027,#20022)
-stmt_containers(#20027,#20024)
-is_method(#20021)
+exprs(#20027,9,#20024,1,"() {}")
+hasLocation(#20027,#20025)
+enclosing_stmt(#20027,#20017)
+expr_containers(#20027,#20001)
 #20028=*
-entry_cfg_node(#20028,#20001)
-#20029=@"loc,{#10000},1,1,1,0"
-locations_default(#20029,#10000,1,1,1,0)
-hasLocation(#20028,#20029)
-#20030=*
-exit_cfg_node(#20030,#20001)
-hasLocation(#20030,#20015)
-successor(#20016,#20023)
-successor(#20024,#20021)
+scopes(#20028,1)
+scopenodes(#20027,#20028)
+scopenesting(#20028,#20022)
+#20029=@"var;{this};{#20028}"
+variables(#20029,"this",#20028)
+#20030=@"var;{arguments};{#20028}"
+variables(#20030,"arguments",#20028)
+is_arguments_object(#20030)
 #20031=*
-entry_cfg_node(#20031,#20024)
-hasLocation(#20031,#20022)
+stmts(#20031,1,#20027,-2,"{}")
+hasLocation(#20031,#20025)
+stmt_containers(#20031,#20027)
+is_method(#20024)
 #20032=*
-exit_cfg_node(#20032,#20024)
-hasLocation(#20032,#20022)
-successor(#20027,#20032)
-successor(#20031,#20027)
-successor(#20023,#20024)
-successor(#20021,#20019)
-successor(#20019,#20017)
-successor(#20017,#20030)
-successor(#20028,#20016)
+entry_cfg_node(#20032,#20001)
+#20033=@"loc,{#10000},1,1,1,0"
+locations_default(#20033,#10000,1,1,1,0)
+hasLocation(#20032,#20033)
+#20034=*
+exit_cfg_node(#20034,#20001)
+hasLocation(#20034,#20015)
+successor(#20017,#20026)
+successor(#20027,#20024)
+#20035=*
+entry_cfg_node(#20035,#20027)
+hasLocation(#20035,#20025)
+#20036=*
+exit_cfg_node(#20036,#20027)
+hasLocation(#20036,#20025)
+successor(#20031,#20036)
+successor(#20035,#20031)
+successor(#20026,#20027)
+successor(#20024,#20020)
+successor(#20020,#20018)
+successor(#20018,#20034)
+successor(#20032,#20017)
 numlines(#10000,1,1,0)
 filetype(#10000,"javascript")

javascript/extractor/tests/cfg/output/trap/classexpr2.js.trap

@@ -52,91 +52,97 @@ locations_default(#20017,#10000,1,13,1,12)
 hasLocation(#20016,#20017)
 toplevels(#20001,0)
 hasLocation(#20001,#20003)
-#20018=*
-stmts(#20018,2,#20001,0,"!class A {};")
-hasLocation(#20018,#20003)
-stmt_containers(#20018,#20001)
+#20018=@"var;{this};{#20000}"
+variables(#20018,"this",#20000)
 #20019=*
-exprs(#20019,18,#20018,0,"!class A {}")
-#20020=@"loc,{#10000},1,1,1,11"
-locations_default(#20020,#10000,1,1,1,11)
-hasLocation(#20019,#20020)
-enclosing_stmt(#20019,#20018)
-expr_containers(#20019,#20001)
-#20021=*
-exprs(#20021,80,#20019,0,"class A {}")
-#20022=@"loc,{#10000},1,2,1,11"
-locations_default(#20022,#10000,1,2,1,11)
-hasLocation(#20021,#20022)
-enclosing_stmt(#20021,#20018)
-expr_containers(#20021,#20001)
-#20023=*
-scopes(#20023,8)
-scopenodes(#20021,#20023)
-scopenesting(#20023,#20000)
-#20024=@"var;{A};{#20023}"
-variables(#20024,"A",#20023)
-#20025=@"local_type_name;{A};{#20023}"
-local_type_names(#20025,"A",#20023)
-#20026=*
-exprs(#20026,78,#20021,0,"A")
-hasLocation(#20026,#20009)
-enclosing_stmt(#20026,#20018)
-expr_containers(#20026,#20001)
-literals("A","A",#20026)
-decl(#20026,#20024)
-typedecl(#20026,#20025)
-#20027=*
-properties(#20027,#20021,2,0,"constructor() {}")
-#20028=@"loc,{#10000},1,10,1,9"
-locations_default(#20028,#10000,1,10,1,9)
-hasLocation(#20027,#20028)
+stmts(#20019,2,#20001,0,"!class A {};")
+hasLocation(#20019,#20003)
+stmt_containers(#20019,#20001)
+#20020=*
+exprs(#20020,18,#20019,0,"!class A {}")
+#20021=@"loc,{#10000},1,1,1,11"
+locations_default(#20021,#10000,1,1,1,11)
+hasLocation(#20020,#20021)
+enclosing_stmt(#20020,#20019)
+expr_containers(#20020,#20001)
+#20022=*
+exprs(#20022,80,#20020,0,"class A {}")
+#20023=@"loc,{#10000},1,2,1,11"
+locations_default(#20023,#10000,1,2,1,11)
+hasLocation(#20022,#20023)
+enclosing_stmt(#20022,#20019)
+expr_containers(#20022,#20001)
+#20024=*
+scopes(#20024,8)
+scopenodes(#20022,#20024)
+scopenesting(#20024,#20000)
+#20025=@"var;{this};{#20024}"
+variables(#20025,"this",#20024)
+#20026=@"var;{A};{#20024}"
+variables(#20026,"A",#20024)
+#20027=@"local_type_name;{A};{#20024}"
+local_type_names(#20027,"A",#20024)
+#20028=*
+exprs(#20028,78,#20022,0,"A")
+hasLocation(#20028,#20009)
+enclosing_stmt(#20028,#20019)
+expr_containers(#20028,#20001)
+literals("A","A",#20028)
+decl(#20028,#20026)
+typedecl(#20028,#20027)
 #20029=*
-exprs(#20029,0,#20027,0,"constructor")
-hasLocation(#20029,#20028)
-enclosing_stmt(#20029,#20018)
-expr_containers(#20029,#20001)
-literals("constructor","constructor",#20029)
-#20030=*
-exprs(#20030,9,#20027,1,"() {}")
-hasLocation(#20030,#20028)
-enclosing_stmt(#20030,#20018)
-expr_containers(#20030,#20001)
+properties(#20029,#20022,2,0,"constructor() {}")
+#20030=@"loc,{#10000},1,10,1,9"
+locations_default(#20030,#10000,1,10,1,9)
+hasLocation(#20029,#20030)
 #20031=*
-scopes(#20031,1)
-scopenodes(#20030,#20031)
-scopenesting(#20031,#20023)
-#20032=@"var;{arguments};{#20031}"
-variables(#20032,"arguments",#20031)
-is_arguments_object(#20032)
+exprs(#20031,0,#20029,0,"constructor")
+hasLocation(#20031,#20030)
+enclosing_stmt(#20031,#20019)
+expr_containers(#20031,#20001)
+literals("constructor","constructor",#20031)
+#20032=*
+exprs(#20032,9,#20029,1,"() {}")
+hasLocation(#20032,#20030)
+enclosing_stmt(#20032,#20019)
+expr_containers(#20032,#20001)
 #20033=*
-stmts(#20033,1,#20030,-2,"{}")
-hasLocation(#20033,#20028)
-stmt_containers(#20033,#20030)
-is_method(#20027)
-#20034=*
-entry_cfg_node(#20034,#20001)
-#20035=@"loc,{#10000},1,1,1,0"
-locations_default(#20035,#10000,1,1,1,0)
-hasLocation(#20034,#20035)
+scopes(#20033,1)
+scopenodes(#20032,#20033)
+scopenesting(#20033,#20024)
+#20034=@"var;{this};{#20033}"
+variables(#20034,"this",#20033)
+#20035=@"var;{arguments};{#20033}"
+variables(#20035,"arguments",#20033)
+is_arguments_object(#20035)
 #20036=*
-exit_cfg_node(#20036,#20001)
-hasLocation(#20036,#20017)
-successor(#20018,#20026)
-successor(#20030,#20027)
+stmts(#20036,1,#20032,-2,"{}")
+hasLocation(#20036,#20030)
+stmt_containers(#20036,#20032)
+is_method(#20029)
 #20037=*
-entry_cfg_node(#20037,#20030)
-hasLocation(#20037,#20028)
-#20038=*
-exit_cfg_node(#20038,#20030)
-hasLocation(#20038,#20028)
-successor(#20033,#20038)
-successor(#20037,#20033)
-successor(#20029,#20030)
-successor(#20027,#20021)
-successor(#20026,#20029)
-successor(#20021,#20019)
-successor(#20019,#20036)
-successor(#20034,#20018)
+entry_cfg_node(#20037,#20001)
+#20038=@"loc,{#10000},1,1,1,0"
+locations_default(#20038,#10000,1,1,1,0)
+hasLocation(#20037,#20038)
+#20039=*
+exit_cfg_node(#20039,#20001)
+hasLocation(#20039,#20017)
+successor(#20019,#20028)
+successor(#20032,#20029)
+#20040=*
+entry_cfg_node(#20040,#20032)
+hasLocation(#20040,#20030)
+#20041=*
+exit_cfg_node(#20041,#20032)
+hasLocation(#20041,#20030)
+successor(#20036,#20041)
+successor(#20040,#20036)
+successor(#20031,#20032)
+successor(#20029,#20022)
+successor(#20028,#20031)
+successor(#20022,#20020)
+successor(#20020,#20039)
+successor(#20037,#20019)
 numlines(#10000,1,1,0)
 filetype(#10000,"javascript")