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

sdk/lib/_internal/compiler/implementation/ssa/codegen.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
index 68646d9c9d8ba5f666e7307140517720efcb158d..44e35ac1ed5fc8017770125eadede7a03e08cc6c 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
@@ -19,23 +19,33 @@ class SsaCodeGeneratorTask extends CompilerTask {
     // 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;
   }