Revert "Revert "Build new IR for functions returning a constant.""

sdk/lib/_internal/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.
 
 part of ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
 
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name => 'SSA code generator';
   NativeEmitter get nativeEmitter => backend.emitter.nativeEmitter;
 
 
   js.Node attachPosition(js.Node node, Element element) {
     // TODO(sra): Attaching positions might be cleaner if the source position
     // was on a wrapping node.
     SourceFile sourceFile = sourceFileOfElement(element);
-    Node expression = element.implementation.parseNode(backend.compiler);
-    Token beginToken;
-    Token endToken;
-    if (expression == null) {
-      // Synthesized node. Use the enclosing element for the location.
-      beginToken = endToken = element.position();
+    if (compiler.irBuilder.hasIr(element)) {
+      IrFunction function = compiler.irBuilder.getIr(element);
+      node.sourcePosition = new OffsetSourceFileLocation(
+          sourceFile, function.offset, function.sourceName);
+      node.endSourcePosition = new OffsetSourceFileLocation(
+          sourceFile, function.endOffset);
     } else {
-      beginToken = expression.getBeginToken();
-      endToken = expression.getEndToken();
-    }
-    // TODO(podivilov): find the right sourceFile here and remove offset checks
-    // below.
-    if (beginToken.charOffset < sourceFile.length) {
-      node.sourcePosition = new SourceFileLocation(sourceFile, beginToken);
-    }
-    if (endToken.charOffset < sourceFile.length) {
-      node.endSourcePosition = new SourceFileLocation(sourceFile, endToken);
+      Node expression = element.implementation.parseNode(backend.compiler);
+      Token beginToken;
+      Token endToken;
+      if (expression == null) {
+        // Synthesized node. Use the enclosing element for the location.
+        beginToken = endToken = element.position();
+      } else {
+        beginToken = expression.getBeginToken();
+        endToken = expression.getEndToken();
+      }
+      // TODO(podivilov): find the right sourceFile here and remove offset
+      // checks below.
+      if (beginToken.charOffset < sourceFile.length) {
+        node.sourcePosition =
+            new TokenSourceFileLocation(sourceFile, beginToken);
+      }
+      if (endToken.charOffset < sourceFile.length) {
+        node.endSourcePosition =
+            new TokenSourceFileLocation(sourceFile, endToken);
+      }
     }
     return node;
   }
 
   SourceFile sourceFileOfElement(Element element) {
     // TODO(johnniwinther): remove the 'element.patch' hack.
     FunctionElement functionElement = element.asFunctionElement();
     if (functionElement != null && functionElement.patch != null) {
       element = functionElement.patch;
     }
@@ skipping 2509 matching lines @@
     if (left.isConstantNull() || right.isConstantNull() ||
         (left.isPrimitive(compiler) &&
          left.instructionType == right.instructionType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }