further simplify the scope translation

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/PythonTreeTranslator.java

@@ -1855,11 +1855,11 @@ private StatementNode createGeneratorExpression(Python3Parser.Comp_forContext co
         // TODO: async
         ScopeInfo old = null;
         if (iteratorInParentScope) {
-            old = environment.pushCurentScope();
+            old = environment.leaveScope();
         }
         ExpressionNode iterator = (ExpressionNode) comp_for.or_test().accept(this);
         if (iteratorInParentScope) {
-            environment.popCurrentScope(old);
+            environment.enterScope(old);
         }
 
         StatementNode targets = assigns.translate(comp_for.exprlist());

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/ScopeInfo.java

@@ -81,8 +81,6 @@ public enum ScopeKind {
     private List<ExpressionNode> defaultArgumentNodes;
     private ReadDefaultArgumentNode[] defaultArgumentReads;
 
-    private int loopCount = 0;
-
     public ScopeInfo(String scopeId, ScopeKind kind, FrameDescriptor frameDescriptor, ScopeInfo parent) {
         this.scopeId = scopeId;
         this.scopeKind = kind;
@@ -96,18 +94,6 @@ public ScopeInfo(String scopeId, ScopeKind kind, FrameDescriptor frameDescriptor
         }
     }
 
-    public void incLoopCount() {
-        loopCount++;
-    }
-
-    public int getLoopCount() {
-        return loopCount;
-    }
-
-    public void resetLoopCount() {
-        this.loopCount = 0;
-    }
-
     public ScopeInfo getFirstChildScope() {
         return firstChildScope;
     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/ScopeTranslator.java

@@ -28,7 +28,6 @@
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Stack;
 import java.util.function.Function;
 
 import org.antlr.v4.runtime.ParserRuleContext;
@@ -347,13 +346,12 @@ public T visitComp_for(Python3Parser.Comp_forContext ctx) {
         declareNames(ctx.exprlist());
         visitExprlist(ctx.exprlist());
 
-        ScopeInfo currentGeneratorScope = environment.getCurrentScope();
-        currentGeneratorScope.incLoopCount();
-        if (currentGeneratorScope.getLoopCount() == 1) {
-            // the first iterator is eagerly evaluated in the outside scope
-            environment.pushCurentScope();
+        if (!(ctx.getParent() instanceof Python3Parser.Comp_iterContext)) {
+            // the first iterator is eagerly evaluated in the outside scope, but any iterator under
+            // the comp_iter is not
+            ScopeInfo currentGeneratorScope = environment.leaveScope();
             visitOr_test(ctx.or_test());
-            environment.popCurrentScope(currentGeneratorScope);
+            environment.enterScope(currentGeneratorScope);
         } else {
             visitOr_test(ctx.or_test());
         }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/TranslationEnvironment.java

@@ -64,7 +64,6 @@ public TranslationEnvironment(PythonLanguage language) {
     public static TranslationEnvironment createFromScope(ScopeInfo scope) {
         TranslationEnvironment environment = new TranslationEnvironment(PythonLanguage.getCurrent());
         environment.currentScope = scope;
-        scope.resetLoopCount();
         ScopeInfo global = scope;
         while (global.getParent() != null) {
             global = global.getParent();
@@ -88,11 +87,12 @@ public ScopeInfo createScope(ParserRuleContext ctx, ScopeInfo.ScopeKind kind, Fr
     public void enterScope(ScopeInfo scope) {
         assert scope != null;
         currentScope = scope;
-        scope.resetLoopCount();
     }
 
-    public void leaveScope() {
+    public ScopeInfo leaveScope() {
+        ScopeInfo old = currentScope;
         currentScope = currentScope.getParent();
+        return old;
     }
 
     public ScopeInfo pushCurentScope() {
@@ -101,15 +101,10 @@ public ScopeInfo pushCurentScope() {
             currentScope = currentScope.getParent();
             return old;
         }
+        assert false;
         return null;
     }
 
-    public void popCurrentScope(ScopeInfo oldScope) {
-        if (oldScope != null) {
-            currentScope = oldScope;
-        }
-    }
-
     public boolean atModuleLevel() {
         assert currentScope != null;
         return currentScope == globalScope;