Implement constant switch as JS switch.

lib/compiler/implementation/ssa/codegen.dart

 // Copyright (c) 2012, 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.
 
 class SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name() => 'SSA code generator';
@@ skipping 615 matching lines @@
         indent++;
         generateStatements(elseGraph);
         indent--;
         addIndented("}");
       }
       buffer.add("\n");
     }
     return true;
   }
 
+  bool visitSwitchInfo(HSwitchBlockInformation info) {
+    bool isExpression = isJSExpression(info.expression);
+    if (!isExpression) {
+      generateStatements(info.expression);
+    }
+    addIndentation();
+    for (LabelElement label in info.labels) {
+      if (label.isTarget) {
+        writeLabel(label);
+        buffer.add(":");
+      }
+    }
+    addIndented("switch (");
+    if (isExpression) {
+      generateExpression(info.expression);
+    } else {
+      use(info.expression.conditionExpression, JSPrecedence.EXPRESSION_PRECEDENCE);

[floitsch, 2012/06/06 11:50:26]

80chars.

[Lasse Reichstein Nielsen, 2012/06/06 13:01:21]

Done.

+    }
+    buffer.add(") {\n");
+    indent++;
+    for (int i = 0; i < info.matchExpressions.length; i++) {
+      for (Constant constant in info.matchExpressions[i]) {
+        addIndented("case ");
+        generateConstant(constant);
+        buffer.add(":\n");
+      }
+      if (i == info.matchExpressions.length - 1 && info.hasDefault) {
+        addIndented("default:\n");
+      }
+      indent++;
+      generateStatements(info.statements[i]);
+      indent--;
+    }
+    indent--;
+    addIndented("}\n");
+    return true;
+  }
+
   bool visitSequenceInfo(HStatementSequenceInformation info) {
     return false;
   }
 
   bool visitSubGraphInfo(HSubGraphBlockInformation info) {
     visitSubGraph(info.subGraph);
     return true;
   }
 
   bool visitSubExpressionInfo(HSubExpressionBlockInformation info) {
@@ skipping 914 matching lines @@
     // We can't use 'visitArguments', since our arguments start at input[0].
     List<HInstruction> inputs = node.inputs;
     for (int i = 0; i < inputs.length; i++) {
       if (i != 0) buffer.add(', ');
       use(inputs[i], JSPrecedence.ASSIGNMENT_PRECEDENCE);
     }
     buffer.add(')');
     endExpression(JSPrecedence.MEMBER_PRECEDENCE);
   }
 
-  visitConstant(HConstant node) {
-    assert(isGenerateAtUseSite(node));
+  void generateConstant(Constant constant) {
     // TODO(floitsch): the compile-time constant handler and the codegen
     // need to work together to avoid the parenthesis. See r4928 for an
     // implementation that still dealt with precedence.
     ConstantHandler handler = compiler.constantHandler;
-    String name = handler.getNameForConstant(node.constant);
+    String name = handler.getNameForConstant(constant);
     if (name === null) {
-      assert(!node.constant.isObject());
-      if (node.constant.isNum()
+      assert(!constant.isObject());
+      if (constant.isNum()
           && expectedPrecedence == JSPrecedence.MEMBER_PRECEDENCE) {
         buffer.add('(');
-        handler.writeConstant(buffer, node.constant);
+        handler.writeConstant(buffer, constant);
         buffer.add(')');
       } else {
-        handler.writeConstant(buffer, node.constant);
+        handler.writeConstant(buffer, constant);
       }
     } else {
       buffer.add(compiler.namer.CURRENT_ISOLATE);
       buffer.add(".");
       buffer.add(name);
     }
+
+  }
+
+  visitConstant(HConstant node) {
+    assert(isGenerateAtUseSite(node));
+    generateConstant(node.constant);
   }
 
   visitLoopBranch(HLoopBranch node) {
     if (subGraph !== null && node.block === subGraph.end) {
       // We are generating code for a loop condition.
       // If doing this as part of a SubGraph traversal, the
       // calling code will handle the control flow logic.
 
       // If we are generating the subgraph as an expression, the
       // condition will be generated as the expression.
@@ skipping 187 matching lines @@
     for (int i = 0; i < indent; i++) {
       buffer.add('  ');
     }
   }
 
   void addIndented(String text) {
     addIndentation();
     buffer.add(text);
   }
 
+  void visitSwitch(HSwitch node) {
+    // Switches are handled using [visitSwitchInfo].
+  }
+
   void visitStatic(HStatic node) {
     world.registerStaticUse(node.element);
     buffer.add(compiler.namer.isolateAccess(node.element));
   }
 
   void visitStaticStore(HStaticStore node) {
     world.registerStaticUse(node.element);
     beginExpression(JSPrecedence.ASSIGNMENT_PRECEDENCE);
     buffer.add(compiler.namer.isolateAccess(node.element));
     buffer.add(' = ');
@@ skipping 764 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }