Compile Time Constants cycle check

compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantResolver.java

Index: compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantResolver.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantResolver.java b/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantResolver.java
new file mode 100644
index 0000000000000000000000000000000000000000..00a042801867503bca8259a9921143eb84e85daf
--- /dev/null
+++ b/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantResolver.java
@@ -0,0 +1,200 @@
+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.google.dart.compiler.resolver;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.dart.compiler.DartCompilerContext;
+import com.google.dart.compiler.ast.DartClass;
+import com.google.dart.compiler.ast.DartExpression;
+import com.google.dart.compiler.ast.DartField;
+import com.google.dart.compiler.ast.DartFunction;
+import com.google.dart.compiler.ast.DartIdentifier;
+import com.google.dart.compiler.ast.DartMethodDefinition;
+import com.google.dart.compiler.ast.DartNewExpression;
+import com.google.dart.compiler.ast.DartNode;
+import com.google.dart.compiler.ast.DartNodeTraverser;
+import com.google.dart.compiler.ast.DartParameter;
+import com.google.dart.compiler.ast.DartPropertyAccess;
+import com.google.dart.compiler.ast.DartUnit;
+import com.google.dart.compiler.ast.DartVariable;
+import com.google.dart.compiler.ast.DartVariableStatement;
+import com.google.dart.compiler.ast.Modifiers;
+
+import java.util.List;
+
+
+/**
+ * Compile-time constants need to infer types, not just in the current units to be resolved, but
+ * in all units.  This pass resolves the right hand side of compile-time constants for the later
+ * type analysis and cycle detection done in {@link CompileTimeConstantAnalysis}.

[mmendez, 2011/11/17 15:32:10]

CompileTimeConstantAnalysis -> CompileTimeConstantAnalyzer?

[zundel, 2011/11/17 16:26:42]

Done.

+ */
+public class CompileTimeConstantResolver {
+
+  private class ConstResolveVisitor extends ResolveVisitor {
+    private class ConstExpressionVisitor extends DartNodeTraverser<Void> {
+
+      @Override
+      public Void visitPropertyAccess(DartPropertyAccess x) {
+        DartNode qualifierNode = x.getQualifier();
+        Element qualifier = null;
+        if (qualifierNode instanceof DartIdentifier) {
+          DartIdentifier qualifierIdent = (DartIdentifier) qualifierNode;
+          qualifier = getContext().getScope().findElement(libraryElement,
+                                                          qualifierIdent
+                                                              .getTargetName());
+          qualifierNode.setSymbol(qualifier);
+        }
+
+        if (qualifier != null) {
+          Element element = null;
+
+          switch (ElementKind.of(qualifier)) {
+            case CLASS:
+              // Must be a static field.
+              element = Elements.findElement(((ClassElement) qualifier), x
+                  .getPropertyName());
+              break;
+
+            case LIBRARY:
+              // Library prefix, lookup the element in the reference library.
+              Scope scope = ((LibraryElement) qualifier).getScope();
+              element = scope
+                  .findElement(scope.getLibrary(), x.getPropertyName());
+              break;
+
+            default:
+              break;
+          }
+          if (element != null) {
+            recordElement(x, element);
+          }
+        }
+        return null;
+      }
+
+      @Override
+      public Void visitIdentifier(DartIdentifier x) {
+        x.visitChildren(this);
+
+        Element element = getContext().getScope()
+            .findElement(libraryElement, x.getTargetName());
+        if (element != null) {
+          recordElement(x, element);
+        }
+        return null;
+      }
+    }
+
+    private final LibraryElement libraryElement;
+    private EnclosingElement currentHolder;
+    private final ResolutionContext topLevelContext;
+    private ResolutionContext context;
+    private boolean isStatic = true;

[mmendez, 2011/11/17 15:32:10]

Nit: should this be a static final or simply inline the constant into
isStaticContext?

[zundel, 2011/11/17 16:26:42]

Done.

+
+    private ConstResolveVisitor(DartUnit unit,
+        DartCompilerContext compilerContext, Scope scope,
+        CoreTypeProvider typeProvider) {
+      super(typeProvider);
+      this.libraryElement = unit.getLibrary() == null ? null : unit
+          .getLibrary().getElement();
+      this.topLevelContext = this.context = new ResolutionContext(scope,
+          compilerContext, typeProvider);
+      this.currentHolder = libraryElement;
+    }
+
+    private void beginClassContext(final DartClass node) {
+      assert !ElementKind.of(currentHolder).equals(ElementKind.CLASS) : "nested class?";
+      currentHolder = node.getSymbol();
+      context = context.extend((ClassElement) currentHolder);
+    }
+
+    private void endClassContext() {
+      currentHolder = libraryElement;
+      context = topLevelContext;
+    }
+
+    @Override
+    ResolutionContext getContext() {
+      return context;
+    }
+
+    @Override
+    boolean isStaticContext() {
+      return isStatic;
+    }
+
+    private void resolveConstantExpression(DartExpression expression) {
+      if (expression != null) {
+        expression.accept(new ConstExpressionVisitor());
+      }
+    }
+
+    @Override
+    public Element visitClass(DartClass node) {
+      assert !ElementKind.of(currentHolder).equals(ElementKind.CLASS) : "nested class?";
+      beginClassContext(node);
+      this.visit(node.getMembers());
+      endClassContext();
+      return null;
+    }
+
+    @Override
+    public Element visitField(DartField node) {
+      resolveConstantExpression(node.getValue());
+      return null;
+    }
+
+    @Override
+    public Element visitMethodDefinition(DartMethodDefinition node) {
+      DartFunction functionNode = node.getFunction();
+      List<DartParameter> parameters = functionNode.getParams();
+      for (DartParameter parameter : parameters) {
+        // Then resolve the default values.
+        resolveConstantExpression(parameter.getDefaultExpr());
+      }
+      return null;
+    }
+
+    @Override
+    public Element visitNewExpression(DartNewExpression node) {
+      if (node.isConst()) {
+        for (DartExpression arg : node.getArgs()) {
+          resolveConstantExpression(arg);
+        }
+      }
+      return null;
+    }
+
+    @Override
+    public Element visitParameter(DartParameter node) {
+      resolveConstantExpression(node.getDefaultExpr());
+      return null;
+    }
+
+    @Override
+    public Element visitVariableStatement(DartVariableStatement node) {
+      for (DartVariable variable : node.getVariables()) {
+        Modifiers modifiers = node.getModifiers();
+        if (modifiers.isStatic() && modifiers.isFinal()
+            && variable.getValue() != null) {
+          resolveConstantExpression(variable.getValue());
+        }
+      }
+      return null;
+    }
+  }
+
+  public void exec(DartUnit unit,
+              DartCompilerContext compilerContext, CoreTypeProvider typeProvider) {
+    exec(unit, compilerContext, unit.getLibrary().getElement().getScope(), typeProvider);
+  }
+
+  @VisibleForTesting
+  public void exec(DartUnit unit, DartCompilerContext compilerContext,
+                   Scope scope, CoreTypeProvider typeProvider) {
+    unit.accept(new ConstResolveVisitor(unit, compilerContext, scope,
+        typeProvider));
+  }
+}