Refactor handling of source map information.

pkg/compiler/lib/src/ssa/builder.dart

Index: pkg/compiler/lib/src/ssa/builder.dart
diff --git a/pkg/compiler/lib/src/ssa/builder.dart b/pkg/compiler/lib/src/ssa/builder.dart
index 43798cd7243067a82a320d3321048a8e36a8730b..6ef2b70b3b168b1441924aa16faf95f76e3e3c8c 100644
--- a/pkg/compiler/lib/src/ssa/builder.dart
+++ b/pkg/compiler/lib/src/ssa/builder.dart
@@ -2446,11 +2446,21 @@ class SsaBuilder extends ResolvedVisitor {
 
   HInstruction attachPosition(HInstruction target, ast.Node node) {
     if (generateSourceMap && node != null) {
-      target.sourcePosition = sourceFileLocationForBeginToken(node);
+      target.sourceInformation = sourceInformationForBeginToken(node);
     }
     return target;
   }
 
+  SourceInformation sourceInformationForBeginToken(ast.Node node) {
+    return new StartEndSourceInformation(sourceFileLocationForBeginToken(node));
+  }
+
+  SourceInformation sourceInformationForBeginEndToken(ast.Node node) {
+    return new StartEndSourceInformation(
+        sourceFileLocationForBeginToken(node),
+        sourceFileLocationForEndToken(node));
+  }
+
   SourceFileLocation sourceFileLocationForBeginToken(ast.Node node) =>
       sourceFileLocationForToken(node, node.getBeginToken());
 
@@ -2734,8 +2744,7 @@ class SsaBuilder extends ResolvedVisitor {
               wrapExpressionGraph(updateGraph),
               conditionBlock.loopInformation.target,
               conditionBlock.loopInformation.labels,
-              sourceFileLocationForBeginToken(loop),
-              sourceFileLocationForEndToken(loop));
+              sourceInformationForBeginEndToken(loop));
 
       startBlock.setBlockFlow(info, current);
       loopInfo.loopBlockInformation = info;
@@ -2952,8 +2961,7 @@ class SsaBuilder extends ResolvedVisitor {
               null,
               loopEntryBlock.loopInformation.target,
               loopEntryBlock.loopInformation.labels,
-              sourceFileLocationForBeginToken(node),
-              sourceFileLocationForEndToken(node));
+              sourceInformationForBeginEndToken(node));
       loopEntryBlock.setBlockFlow(loopBlockInfo, current);
       loopInfo.loopBlockInformation = loopBlockInfo;
     } else {