Improve tracer output for bailouts.

lib/compiler/implementation/ssa/tracer.dart

Index: lib/compiler/implementation/ssa/tracer.dart
diff --git a/lib/compiler/implementation/ssa/tracer.dart b/lib/compiler/implementation/ssa/tracer.dart
index 971f7d874a188345fde5cf21fccea02bf58bc094..e3709e9e34a8a16f466d15ddf14a5a77bdd7a8e4 100644
--- a/lib/compiler/implementation/ssa/tracer.dart
+++ b/lib/compiler/implementation/ssa/tracer.dart
@@ -415,8 +415,15 @@ class HInstructionStringifier implements HVisitor<String> {
       case HType.UNKNOWN: type = 'unknown'; break;
       default: unreachable();
     }
-    String onString = node.isOn ? "on" : "off";
-    return "TypeGuard: ${temporaryId(node.inputs[0])} is $type ($onString)";
+    StringBuffer result = new StringBuffer();
+    result.add("TypeGuard(${node.isOn ? "on" : "off"}):");
+    result.add(" ${temporaryId(node.guarded)} is $type");
+    result.add(" env:");
+    List<HInstruction> inputs = node.inputs;
+    for (int i = 0; i < inputs.length - 1; i++) {
+      result.add(" ${temporaryId(inputs[i])}");
+    }
+    return result.toString();

[kasperl, 2012/04/19 06:45:57]

I kind of like doing this in this way:

   var on = node.isOn ? "on" : "off";
   var id = temporaryId(node.guarded);
   return "TypeGuard($on): $id is $type env: $buffer";

and get rid of the first result.add() calls. WDYT? I think it makes the format
easier to grok.

[floitsch, 2012/04/19 12:06:27]

Done.

   }
 
   String visitIs(HIs node) {