Track fields which are known to be always set to integer constants

lib/compiler/implementation/ssa/optimize.dart

 // 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.
 
 interface OptimizationPhase {
   String get name();
   void visitGraph(HGraph graph);
 }
 
 class SsaOptimizerTask extends CompilerTask {
@@ skipping 455 matching lines @@
           node.block.addBefore(node, target);
           HEquals result = new HEquals(target, node.left, node.right);
           if (onlyUsedInBoolify) {
             result.usesBoolifiedInterceptor = true;
             result.propagatedType = HType.BOOLEAN;
           }
           return result;
         }
       }
     }
 

[ngeoffray, 2012/06/14 13:01:21]

Add a comment on why we're interested in recompiling the method.

[Søren Gjesse, 2012/06/15 13:19:59]

Done.

+    if (node.left is HFieldGet && node.right is HConstant) {

[ngeoffray, 2012/06/14 13:01:21]

check node.right.isInteger()

[Søren Gjesse, 2012/06/15 13:19:59]

Done.

+      HFieldGet left = node.left;
+      HConstant right = node.right;
+      Type type = left.receiver.propagatedType.computeType(compiler);
+      if (left.element != null &&
+          compiler.codegenWorld.hasFieldOnlyIntegerSetters(
+              type, left.element.name)) {
+        switch (compiler.pass) {
+          case 1:
+            compiler.enqueuer.codegen.registerRecompilationCandidate(
+                work.element);
+            break;
+          case 2:
+            // Codegen will generate the faster code now.
+            break;
+        }
+        return node;

[ngeoffray, 2012/06/14 13:01:21]

This code does not really belong here. I would create a separate pass that tries
to find things that would be really valuable that would deserve having the
method a recompilation candidate.

[Søren Gjesse, 2012/06/15 13:19:59]

Moved all this to a new SSA pass.

+      }
+    }
+
     // All other cases are dealt with by the [visitRelational] and
     // [visitInvokeBinary], which are visited by invoking the [super]'s
     // visit method.
     return super.visitEquals(node);
   }
 
   HInstruction visitTypeGuard(HTypeGuard node) {
     HInstruction value = node.guarded;
     // If the intersection of the types is still the incoming type then
     // the incoming type was a subtype of the guarded type, and no check
@@ skipping 675 matching lines @@
         // the if block terminates. So any use of the instruction
         // after the join block should be changed to the new
         // instruction.
         changeUsesDominatedBy(ifUser.joinBlock, input, convertedType);
       }
       // TODO(ngeoffray): Also change uses for the then block on a HType
       // that knows it is not of a specific Type.
     }
   }
 }