diff --git a/packages/flutter_tools/lib/src/base/build.dart b/packages/flutter_tools/lib/src/base/build.dart
index 81aacb90609..ef00578ec10 100644
--- a/packages/flutter_tools/lib/src/base/build.dart
+++ b/packages/flutter_tools/lib/src/base/build.dart
@@ -7,7 +7,7 @@ import 'dart:convert' show JSON;
 
 import 'package:crypto/crypto.dart' show md5;
 import 'package:meta/meta.dart';
-import 'package:quiver/core.dart' show hash3;
+import 'package:quiver/core.dart' show hash4;
 
 import '../artifacts.dart';
 import '../build_info.dart';
@@ -62,7 +62,7 @@ class GenSnapshot {
 /// build step. This assumes that build outputs are strictly a product of the
 /// input files.
 class Checksum {
-  Checksum.fromFiles(SnapshotType type, Set<String> inputPaths) {
+  Checksum.fromFiles(SnapshotType type, this._mainPath, Set<String> inputPaths) {
     final Iterable<File> files = inputPaths.map(fs.file);
     final Iterable<File> missingInputs = files.where((File file) => !file.existsSync());
     if (missingInputs.isNotEmpty)
@@ -99,11 +99,16 @@ class Checksum {
     if (_targetPlatform == null)
       throw new ArgumentError('Target platform unspecified in checksum JSON');
 
+    _mainPath = content['entrypoint'];
+    if (_mainPath == null)
+      throw new ArgumentError('Entrypoint unspecified in checksum JSON');
+
     _checksums = content['files'];
     if (_checksums == null)
       throw new ArgumentError('File checksums unspecified in checksum JSON');
   }
 
+  String _mainPath;
   String _buildMode;
   String _targetPlatform;
   Map<String, String> _checksums;
@@ -111,6 +116,7 @@ class Checksum {
   String toJson() => JSON.encode(<String, dynamic>{
     'version': FlutterVersion.instance.frameworkRevision,
     'buildMode': _buildMode,
+    'entrypoint': _mainPath,
     'targetPlatform': _targetPlatform,
     'files': _checksums,
   });
@@ -120,12 +126,13 @@ class Checksum {
     return other is Checksum &&
         _buildMode == other._buildMode &&
         _targetPlatform == other._targetPlatform &&
+        _mainPath == other._mainPath &&
         _checksums.length == other._checksums.length &&
         _checksums.keys.every((String key) => _checksums[key] == other._checksums[key]);
   }
 
   @override
-  int get hashCode => hash3(_buildMode, _targetPlatform, _checksums);
+  int get hashCode => hash4(_buildMode, _targetPlatform, _mainPath, _checksums);
 }
 
 final RegExp _separatorExpr = new RegExp(r'([^\\]) ');
@@ -238,7 +245,7 @@ class Snapshotter {
         final Checksum oldChecksum = new Checksum.fromJson(await checksumFile.readAsString());
         final Set<String> checksumPaths = await readDepfile(depfilePath)
           ..addAll(<String>[outputSnapshotPath, mainPath]);
-        final Checksum newChecksum = new Checksum.fromFiles(type, checksumPaths);
+        final Checksum newChecksum = new Checksum.fromFiles(type, mainPath, checksumPaths);
         return oldChecksum != newChecksum;
       }
     } catch (e, s) {
@@ -252,7 +259,7 @@ class Snapshotter {
     try {
       final Set<String> checksumPaths = await readDepfile(depfilePath)
         ..addAll(<String>[outputSnapshotPath, mainPath]);
-      final Checksum checksum = new Checksum.fromFiles(type, checksumPaths);
+      final Checksum checksum = new Checksum.fromFiles(type, mainPath, checksumPaths);
       await fs.file(checksumsPath).writeAsString(checksum.toJson());
     } catch (e, s) {
       // Log exception and continue, this step is a performance improvement only.
diff --git a/packages/flutter_tools/lib/src/commands/build_aot.dart b/packages/flutter_tools/lib/src/commands/build_aot.dart
index 4409374dfb9..215d4d58d36 100644
--- a/packages/flutter_tools/lib/src/commands/build_aot.dart
+++ b/packages/flutter_tools/lib/src/commands/build_aot.dart
@@ -297,7 +297,7 @@ Future<String> _buildAotSnapshot(
       final Set<String> snapshotInputPaths = await readDepfile(dependencies)
         ..add(mainPath)
         ..addAll(outputPaths);
-      final Checksum newChecksum = new Checksum.fromFiles(snapshotType, snapshotInputPaths);
+      final Checksum newChecksum = new Checksum.fromFiles(snapshotType, mainPath, snapshotInputPaths);
       if (oldChecksum == newChecksum) {
         printStatus('Skipping AOT snapshot build. Checksums match.');
         return outputPath;
@@ -375,7 +375,7 @@ Future<String> _buildAotSnapshot(
     final Set<String> snapshotInputPaths = await readDepfile(dependencies)
       ..add(mainPath)
       ..addAll(outputPaths);
-    final Checksum checksum = new Checksum.fromFiles(snapshotType, snapshotInputPaths);
+    final Checksum checksum = new Checksum.fromFiles(snapshotType, mainPath, snapshotInputPaths);
     await checksumFile.writeAsString(checksum.toJson());
   } catch (e, s) {
     // Log exception and continue, this step is a performance improvement only.
diff --git a/packages/flutter_tools/test/base/build_test.dart b/packages/flutter_tools/test/base/build_test.dart
index de3e28ce342..e8788784ebb 100644
--- a/packages/flutter_tools/test/base/build_test.dart
+++ b/packages/flutter_tools/test/base/build_test.dart
@@ -75,7 +75,7 @@ void main() {
         await fs.file('a.dart').create();
         const SnapshotType snapshotType = const SnapshotType(TargetPlatform.ios, BuildMode.debug);
         expect(
-          () => new Checksum.fromFiles(snapshotType, <String>['a.dart', 'b.dart'].toSet()),
+          () => new Checksum.fromFiles(snapshotType, 'a.dart', <String>['a.dart', 'b.dart'].toSet()),
           throwsA(anything),
         );
       }, overrides: <Type, Generator>{ FileSystem: () => fs });
@@ -84,7 +84,7 @@ void main() {
         await fs.file('a.dart').create();
         const SnapshotType snapshotType = const SnapshotType(TargetPlatform.ios, null);
         expect(
-          () => new Checksum.fromFiles(snapshotType, <String>['a.dart', 'b.dart'].toSet()),
+          () => new Checksum.fromFiles(snapshotType, 'a.dart', <String>['a.dart', 'b.dart'].toSet()),
           throwsA(anything),
         );
       }, overrides: <Type, Generator>{ FileSystem: () => fs });
@@ -93,7 +93,7 @@ void main() {
         await fs.file('a.dart').create();
         const SnapshotType snapshotType = const SnapshotType(null, BuildMode.debug);
         expect(
-          new Checksum.fromFiles(snapshotType, <String>['a.dart'].toSet()),
+          new Checksum.fromFiles(snapshotType, 'a.dart', <String>['a.dart'].toSet()),
           isNotNull,
         );
       }, overrides: <Type, Generator>{ FileSystem: () => fs });
@@ -102,13 +102,14 @@ void main() {
         await fs.file('a.dart').writeAsString('This is a');
         await fs.file('b.dart').writeAsString('This is b');
         const SnapshotType snapshotType = const SnapshotType(TargetPlatform.ios, BuildMode.debug);
-        final Checksum checksum = new Checksum.fromFiles(snapshotType, <String>['a.dart', 'b.dart'].toSet());
+        final Checksum checksum = new Checksum.fromFiles(snapshotType, 'a.dart', <String>['a.dart', 'b.dart'].toSet());
 
         final Map<String, dynamic> json = JSON.decode(checksum.toJson());
-        expect(json, hasLength(4));
+        expect(json, hasLength(5));
         expect(json['version'], mockVersion.frameworkRevision);
         expect(json['buildMode'], BuildMode.debug.toString());
         expect(json['targetPlatform'], TargetPlatform.ios.toString());
+        expect(json['entrypoint'], 'a.dart');
         expect(json['files'], hasLength(2));
         expect(json['files']['a.dart'], '8a21a15fad560b799f6731d436c1b698');
         expect(json['files']['b.dart'], '6f144e08b58cd0925328610fad7ac07c');
@@ -130,6 +131,7 @@ void main() {
           'version': kVersion,
           'buildMode': BuildMode.release.toString(),
           'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -138,10 +140,11 @@ void main() {
         final Checksum checksum = new Checksum.fromJson(json);
 
         final Map<String, dynamic> content = JSON.decode(checksum.toJson());
-        expect(content, hasLength(4));
+        expect(content, hasLength(5));
         expect(content['version'], mockVersion.frameworkRevision);
         expect(content['buildMode'], BuildMode.release.toString());
         expect(content['targetPlatform'], TargetPlatform.ios.toString());
+        expect(content['entrypoint'], 'a.dart');
         expect(content['files']['a.dart'], '8a21a15fad560b799f6731d436c1b698');
         expect(content['files']['b.dart'], '6f144e08b58cd0925328610fad7ac07c');
       }, overrides: <Type, Generator>{
@@ -152,6 +155,8 @@ void main() {
         final String json = JSON.encode(<String, dynamic>{
           'version': 'bad',
           'buildMode': BuildMode.release.toString(),
+          'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -169,6 +174,7 @@ void main() {
           'version': kVersion,
           'buildMode': BuildMode.debug.toString(),
           'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -186,6 +192,7 @@ void main() {
           'version': kVersion,
           'buildMode': BuildMode.debug.toString(),
           'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -198,11 +205,30 @@ void main() {
         FlutterVersion: () => mockVersion,
       });
 
+      testUsingContext('reports not equal if entrypoints do not match', () async {
+        final Map<String, dynamic> a = <String, dynamic>{
+          'version': kVersion,
+          'buildMode': BuildMode.debug.toString(),
+          'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
+          'files': <String, dynamic>{
+            'a.dart': '8a21a15fad560b799f6731d436c1b698',
+            'b.dart': '6f144e08b58cd0925328610fad7ac07c',
+          },
+        };
+        final Map<String, dynamic> b = new Map<String, dynamic>.from(a);
+        b['entrypoint'] = 'b.dart';
+        expect(new Checksum.fromJson(JSON.encode(a)) == new Checksum.fromJson(JSON.encode(b)), isFalse);
+      }, overrides: <Type, Generator>{
+        FlutterVersion: () => mockVersion,
+      });
+
       testUsingContext('reports not equal if checksums do not match', () async {
         final Map<String, dynamic> a = <String, dynamic>{
           'version': kVersion,
           'buildMode': BuildMode.debug.toString(),
           'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -223,6 +249,7 @@ void main() {
           'version': kVersion,
           'buildMode': BuildMode.debug.toString(),
           'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -243,6 +270,7 @@ void main() {
           'version': kVersion,
           'buildMode': BuildMode.debug.toString(),
           'targetPlatform': TargetPlatform.ios.toString(),
+          'entrypoint': 'a.dart',
           'files': <String, dynamic>{
             'a.dart': '8a21a15fad560b799f6731d436c1b698',
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
@@ -398,12 +426,12 @@ void main() {
       final _FakeGenSnapshot genSnapshot = new _FakeGenSnapshot(
         snapshotPath: 'output.snapshot',
         depfilePath: 'output.snapshot.d',
-        depfileContent: 'output.snapshot : other.dart',
+        depfileContent: 'output.snapshot : main.dart other.dart',
       );
       context.setVariable(GenSnapshot, genSnapshot);
 
-      await fs.file('main.dart').writeAsString('void main() {}');
-      await fs.file('other.dart').writeAsString('void main() { print("Kanpai ima kimi wa jinsei no ookina ookina butai ni tachi"); }');
+      await fs.file('main.dart').writeAsString('import "other.dart";\nvoid main() {}');
+      await fs.file('other.dart').writeAsString('import "main.dart";\nvoid main() {}');
       await fs.file('output.snapshot').create();
       await fs.file('output.snapshot.d').writeAsString('output.snapshot : main.dart');
       await fs.file('output.snapshot.d.checksums').writeAsString(JSON.encode(<String, dynamic>{
@@ -411,7 +439,8 @@ void main() {
         'buildMode': BuildMode.debug.toString(),
         'targetPlatform': '',
         'files': <String, dynamic>{
-          'main.dart': '27f5ebf0f8c559b2af9419d190299a5e',
+          'main.dart': 'bc096b33f14dde5e0ffaf93a1d03395c',
+          'other.dart': 'e0c35f083f0ad76b2d87100ec678b516',
           'output.snapshot': 'd41d8cd98f00b204e9800998ecf8427e',
         },
       }));
@@ -424,8 +453,9 @@ void main() {
 
       expect(genSnapshot.callCount, 1);
       final Map<String, dynamic> json = JSON.decode(await fs.file('output.snapshot.d.checksums').readAsString());
-      expect(json['files'], hasLength(2));
-      expect(json['files']['other.dart'], '3238d0ae341339b1731d3c2e195ad177');
+      expect(json['files'], hasLength(3));
+      expect(json['files']['main.dart'], 'bc096b33f14dde5e0ffaf93a1d03395c');
+      expect(json['files']['other.dart'], 'e0c35f083f0ad76b2d87100ec678b516');
       expect(json['files']['output.snapshot'], 'd41d8cd98f00b204e9800998ecf8427e');
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
@@ -440,6 +470,7 @@ void main() {
         'version': '$kVersion',
         'buildMode': BuildMode.debug.toString(),
         'targetPlatform': '',
+        'entrypoint': 'main.dart',
         'files': <String, dynamic>{
           'main.dart': '27f5ebf0f8c559b2af9419d190299a5e',
           'output.snapshot': 'd41d8cd98f00b204e9800998ecf8427e',