Revert "[SDK] Adds an SDK hash to kernels and the VM."

This reverts commit edde575dcd.

Reason for revert: Breaks the Dart to Flutter roll and golem

Original change's description:
> [SDK] Adds an SDK hash to kernels and the VM.
>
> Adds a new SDK hash to kernels and the VM which is optionally checked
> to verify kernels are built for the same SDK as the VM.
> This helps catch incompatibilities that are currently causing
> subtle bugs and (not so subtle) crashes.
>
> The SDK hash is encoded in kernels as a new field in components.
> The hash is derived from the 10 byte git short hash.
>
> This new check can be disabled via:
>   tools/gn.py ... --no-verify-sdk-hash
>
> This CL bumps the min. (and max.) supported kernel format version,
> making the VM backwards incompatible from this point back.
>
> Bug: https://github.com/dart-lang/sdk/issues/41802
> Change-Id: I3cbb2d481239ee64dafdaa0e4aac36c80281931b
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/150343
> Commit-Queue: Clement Skau <cskau@google.com>
> Reviewed-by: Jens Johansen <jensj@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>

TBR=kustermann@google.com,jensj@google.com,cskau@google.com

Change-Id: I34cc7d378e2babdaaca4d932d19c19d0f35422fc
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: https://github.com/dart-lang/sdk/issues/41802
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152703
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>

DEPS

@@ -512,7 +512,7 @@ deps = {
     "packages": [
       {
         "package": "dart/cfe/dart2js_dills",
-        "version": "binary_version:43_2",
+        "version": "binary_version:42",
       }
     ],
     "dep_type": "cipd",

pkg/front_end/test/binary_md_dill_reader.dart

@@ -473,33 +473,31 @@ class BinaryMdDillReader {
         type = type.substring(0, type.indexOf("["));
         type = _lookupGenericType(typeNames, type, types);
 
-        int intCount = int.tryParse(count) ?? -1;
+        int intCount = -1;
-        if (intCount == -1) {
+        if (vars[count] != null && vars[count] is int) {
-          if (vars[count] != null && vars[count] is int) {
+          intCount = vars[count];
-            intCount = vars[count];
+        } else if (count.contains(".")) {
-          } else if (count.contains(".")) {
+          List<String> countData =
-            List<String> countData =
+              count.split(regExpSplit).map((s) => s.trim()).toList();
-                count.split(regExpSplit).map((s) => s.trim()).toList();
+          if (vars[countData[0]] != null) {
-            if (vars[countData[0]] != null) {
+            dynamic v = vars[countData[0]];
-              dynamic v = vars[countData[0]];
+            if (v is Map &&
-              if (v is Map &&
+                countData[1] == "last" &&
-                  countData[1] == "last" &&
+                v["items"] is List &&
-                  v["items"] is List &&
+                v["items"].last is int) {
-                  v["items"].last is int) {
+              intCount = v["items"].last;
-                intCount = v["items"].last;
+            } else if (v is Map && v[countData[1]] != null) {
-              } else if (v is Map && v[countData[1]] != null) {
+              v = v[countData[1]];
-                v = v[countData[1]];
+              if (v is Map && v[countData[2]] != null) {
-                if (v is Map && v[countData[2]] != null) {
+                v = v[countData[2]];
-                  v = v[countData[2]];
+                if (v is int) intCount = v;
-                  if (v is int) intCount = v;
+              } else if (v is int &&
-                } else if (v is int &&
+                  countData.length == 4 &&
-                    countData.length == 4 &&
+                  countData[2] == "+") {
-                    countData[2] == "+") {
+                intCount = v + int.parse(countData[3]);
-                  intCount = v + int.parse(countData[3]);
-                }
-              } else {
-                throw "Unknown dot to int ($count)";
               }
+            } else {
+              throw "Unknown dot to int ($count)";
             }
           }
         }

pkg/front_end/test/spell_checking_list_code.txt

@@ -313,7 +313,6 @@ disallow
 disambiguator
 disjoint
 dispatched
-distribute
 divided
 dmitryas
 doc
@@ -326,7 +325,6 @@ downloaded
 downloading
 dq
 dquote
-dsdk
 dst
 dummy
 dupdate
@@ -437,14 +435,12 @@ futured
 futureor
 g
 gardening
-gen
 generation
 gets
 getter1a
 getter1b
 getting
 gft
-git
 github
 glb
 glob

pkg/kernel/binary.md

@@ -143,8 +143,7 @@ type CanonicalName {
 
 type ComponentFile {
   UInt32 magic = 0x90ABCDEF;
-  UInt32 formatVersion = 43;
+  UInt32 formatVersion = 42;
-  Byte[10] shortSdkHash;
   List<String> problemsAsJson; // Described in problems.md.
   Library[] libraries;
   UriSource sourceMap;

pkg/kernel/lib/binary/ast_from_binary.dart

@@ -5,7 +5,6 @@ library kernel.ast_from_binary;
 
 import 'dart:core' hide MapEntry;
 import 'dart:developer';
-import 'dart:convert';
 import 'dart:typed_data';
 
 import '../ast.dart';
@@ -29,22 +28,11 @@ class InvalidKernelVersionError {
   InvalidKernelVersionError(this.version);
 
   String toString() {
-    return 'Unexpected Kernel Format Version ${version} '
+    return 'Unexpected Kernel version ${version} '
         '(expected ${Tag.BinaryFormatVersion}).';
   }
 }
 
-class InvalidKernelSdkVersionError {
-  final String version;
-
-  InvalidKernelSdkVersionError(this.version);
-
-  String toString() {
-    return 'Unexpected Kernel SDK Version ${version} '
-        '(expected ${expectedSdkHash}).';
-  }
-}
-
 class CompilationModeError {
   final String message;
 
@@ -496,13 +484,6 @@ class BinaryBuilder {
     if (_bytes.length == 0) throw new StateError("Empty input given.");
   }
 
-  void _readAndVerifySdkHash() {
-    final sdkHash = ascii.decode(readBytes(sdkHashLength));
-    if (!isValidSdkHash(sdkHash)) {
-      throw InvalidKernelSdkVersionError(sdkHash);
-    }
-  }
-
   /// Deserializes a kernel component and stores it in [component].
   ///
   /// When linking with a non-empty component, canonical names must have been
@@ -530,9 +511,6 @@ class BinaryBuilder {
       if (version != Tag.BinaryFormatVersion) {
         throw InvalidKernelVersionError(version);
       }
-
-      _readAndVerifySdkHash();
-
       _byteOffset = offset;
       List<int> componentFileSizes = _indexComponents();
       if (componentFileSizes.length > 1) {
@@ -716,8 +694,6 @@ class BinaryBuilder {
       throw InvalidKernelVersionError(formatVersion);
     }
 
-    _readAndVerifySdkHash();
-
     // Read component index from the end of this ComponentFiles serialized data.
     _ComponentIndex index = _readComponentIndex(componentFileSize);
 
@@ -742,8 +718,6 @@ class BinaryBuilder {
       throw InvalidKernelVersionError(formatVersion);
     }
 
-    _readAndVerifySdkHash();
-
     List<String> problemsAsJson = readListOfStrings();
     if (problemsAsJson != null) {
       component.problemsAsJson ??= <String>[];

pkg/kernel/lib/binary/ast_to_binary.dart

@@ -4,7 +4,6 @@
 library kernel.ast_to_binary;
 
 import 'dart:core' hide MapEntry;
-import 'dart:convert';
 import 'dart:developer';
 import 'dart:io' show BytesBuilder;
 import 'dart:typed_data';
@@ -538,7 +537,6 @@ class BinaryPrinter implements Visitor<void>, BinarySink {
       final componentOffset = getBufferOffset();
       writeUInt32(Tag.ComponentFile);
       writeUInt32(Tag.BinaryFormatVersion);
-      writeBytes(ascii.encode(expectedSdkHash));
       writeListOfStrings(component.problemsAsJson);
       indexLinkTable(component);
       _collectMetadata(component);

pkg/kernel/lib/binary/tag.dart

@@ -149,7 +149,7 @@ class Tag {
   /// Internal version of kernel binary format.
   /// Bump it when making incompatible changes in kernel binaries.
   /// Keep in sync with runtime/vm/kernel_binary.h, pkg/kernel/binary.md.
-  static const int BinaryFormatVersion = 43;
+  static const int BinaryFormatVersion = 42;
 }
 
 abstract class ConstantTag {
@@ -169,27 +169,3 @@ abstract class ConstantTag {
   static const int UnevaluatedConstant = 12;
   // 13 is occupied by [SetConstant]
 }
-
-const int sdkHashLength = 10; // Bytes, a Git "short hash".
-
-const String sdkHashNull = '0000000000';
-
-// Will be correct hash for Flutter SDK / Dart SDK we distribute.
-// If non-null we will validate when consuming kernel, will use when producing
-// kernel.
-// If null, local development setting (e.g. run gen_kernel.dart from source),
-// we put 0x00..00 into when producing, do not validate when consuming.
-String get expectedSdkHash {
-  final sdkHash =
-      const String.fromEnvironment('sdk_hash', defaultValue: sdkHashNull);
-  if (sdkHash.length != 10) {
-    throw '-Dsdk_hash=<hash> must be a 10 byte string!';
-  }
-  return sdkHash;
-}
-
-bool isValidSdkHash(String sdkHash) {
-  return (sdkHash == sdkHashNull ||
-      expectedSdkHash == sdkHashNull ||
-      sdkHash == expectedSdkHash);
-}

runtime/bin/BUILD.gn

@@ -964,11 +964,9 @@ prebuilt_dart_action("gen_kernel_bytecode_dill") {
 
   abs_depfile = rebase_path(depfile)
   rebased_output = rebase_path(output, root_build_dir)
-
   vm_args = [
     "--depfile=$abs_depfile",
     "--depfile_output_filename=$rebased_output",
-    "-Dsdk_hash=$sdk_hash",
   ]
 
   args = [

runtime/tests/vm/dart/sdk_hash_test.dart

@@ -1,88 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import 'dart:async';
-import 'dart:convert';
-import 'dart:io';
-import 'dart:typed_data';
-
-import 'package:path/path.dart' as path;
-import 'package:expect/expect.dart';
-
-import 'snapshot_test_helper.dart';
-
-// Keep in sync with pkg/kernel/lib/binary/tag.dart:
-const tagComponentFile = [0x90, 0xAB, 0xCD, 0xEF];
-const tagBinaryFormatVersion = [0x00, 0x00, 0x00, 43];
-
-Future<void> main(List<String> args) async {
-  if (args.length == 1 && args[0] == '--child') {
-    print('Hello, SDK Hash!');
-    return;
-  }
-
-  final String sourcePath =
-      path.join('runtime', 'tests', 'vm', 'dart_2', 'sdk_hash_test.dart');
-
-  await withTempDir((String tmp) async {
-    final String dillPath = path.join(tmp, 'test.dill');
-
-    {
-      final result = await Process.run(dart, [
-        genKernel,
-        '--platform',
-        platformDill,
-        '-o',
-        dillPath,
-        sourcePath,
-      ]);
-      Expect.equals('', result.stderr);
-      Expect.equals(0, result.exitCode);
-      Expect.equals('', result.stdout);
-    }
-
-    {
-      final result = await Process.run(dart, [dillPath, '--child']);
-      Expect.equals('', result.stderr);
-      Expect.equals(0, result.exitCode);
-      Expect.equals('Hello, SDK Hash!', result.stdout.trim());
-    }
-
-    // Invalidate the SDK hash in the kernel dill:
-    {
-      final myFile = File(dillPath);
-      Uint8List bytes = myFile.readAsBytesSync();
-      // The SDK Hash is located after the ComponentFile and BinaryFormatVersion
-      // tags (both UInt32).
-      Expect.listEquals(tagComponentFile, bytes.sublist(0, 4));
-      Expect.listEquals(tagBinaryFormatVersion, bytes.sublist(4, 8));
-      // Flip the first byte in the hash:
-      bytes[8] ^= bytes[8];
-      myFile.writeAsBytesSync(bytes);
-    }
-
-    {
-      final result = await Process.run(dart, [dillPath, '--child']);
-      Expect.equals(
-          'Can\'t load Kernel binary: Invalid SDK hash.', result.stderr.trim());
-      Expect.equals(253, result.exitCode);
-      Expect.equals('', result.stdout);
-    }
-
-    // Zero out the SDK hash in the kernel dill to disable the check:
-    {
-      final myFile = File(dillPath);
-      Uint8List bytes = myFile.readAsBytesSync();
-      bytes.setRange(8, 18, ascii.encode('0000000000'));
-      myFile.writeAsBytesSync(bytes);
-    }
-
-    {
-      final result = await Process.run(dart, [dillPath, '--child']);
-      Expect.equals('', result.stderr);
-      Expect.equals(0, result.exitCode);
-      Expect.equals('Hello, SDK Hash!', result.stdout.trim());
-    }
-  });
-}

runtime/tests/vm/dart/snapshot_test_helper.dart

@@ -48,7 +48,6 @@ final String executableSuffix = Platform.isWindows ? ".exe" : "";
 final String buildDir = p.dirname(Platform.executable);
 final String platformDill = p.join(buildDir, "vm_platform_strong.dill");
 final String genSnapshot = p.join(buildDir, "gen_snapshot${executableSuffix}");
-final String dart = p.join(buildDir, "dart${executableSuffix}");
 final String dartPrecompiledRuntime =
     p.join(buildDir, "dart_precompiled_runtime${executableSuffix}");
 final String genKernel = p.join("pkg", "vm", "bin", "gen_kernel.dart");

runtime/tests/vm/dart_2/sdk_hash_test.dart

@@ -1,88 +0,0 @@
-// Copyright (c) 2020, 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.
-
-import 'dart:async';
-import 'dart:convert';
-import 'dart:io';
-import 'dart:typed_data';
-
-import 'package:path/path.dart' as path;
-import 'package:expect/expect.dart';
-
-import 'snapshot_test_helper.dart';
-
-// Keep in sync with pkg/kernel/lib/binary/tag.dart:
-const tagComponentFile = [0x90, 0xAB, 0xCD, 0xEF];
-const tagBinaryFormatVersion = [0x00, 0x00, 0x00, 43];
-
-Future<void> main(List<String> args) async {
-  if (args.length == 1 && args[0] == '--child') {
-    print('Hello, SDK Hash!');
-    return;
-  }
-
-  final String sourcePath =
-      path.join('runtime', 'tests', 'vm', 'dart_2', 'sdk_hash_test.dart');
-
-  await withTempDir((String tmp) async {
-    final String dillPath = path.join(tmp, 'test.dill');
-
-    {
-      final result = await Process.run(dart, [
-        genKernel,
-        '--platform',
-        platformDill,
-        '-o',
-        dillPath,
-        sourcePath,
-      ]);
-      Expect.equals('', result.stderr);
-      Expect.equals(0, result.exitCode);
-      Expect.equals('', result.stdout);
-    }
-
-    {
-      final result = await Process.run(dart, [dillPath, '--child']);
-      Expect.equals('', result.stderr);
-      Expect.equals(0, result.exitCode);
-      Expect.equals('Hello, SDK Hash!', result.stdout.trim());
-    }
-
-    // Invalidate the SDK hash in the kernel dill:
-    {
-      final myFile = File(dillPath);
-      Uint8List bytes = myFile.readAsBytesSync();
-      // The SDK Hash is located after the ComponentFile and BinaryFormatVersion
-      // tags (both UInt32).
-      Expect.listEquals(tagComponentFile, bytes.sublist(0, 4));
-      Expect.listEquals(tagBinaryFormatVersion, bytes.sublist(4, 8));
-      // Flip the first byte in the hash:
-      bytes[8] ^= bytes[8];
-      myFile.writeAsBytesSync(bytes);
-    }
-
-    {
-      final result = await Process.run(dart, [dillPath, '--child']);
-      Expect.equals(
-          'Can\'t load Kernel binary: Invalid SDK hash.', result.stderr.trim());
-      Expect.equals(253, result.exitCode);
-      Expect.equals('', result.stdout);
-    }
-
-    // Zero out the SDK hash in the kernel dill to disable the check:
-    {
-      final myFile = File(dillPath);
-      Uint8List bytes = myFile.readAsBytesSync();
-      bytes.setRange(8, 18, ascii.encode('0000000000'));
-      myFile.writeAsBytesSync(bytes);
-    }
-
-    {
-      final result = await Process.run(dart, [dillPath, '--child']);
-      Expect.equals('', result.stderr);
-      Expect.equals(0, result.exitCode);
-      Expect.equals('Hello, SDK Hash!', result.stdout.trim());
-    }
-  });
-}

runtime/tests/vm/dart_2/snapshot_test_helper.dart

@@ -48,7 +48,6 @@ final String executableSuffix = Platform.isWindows ? ".exe" : "";
 final String buildDir = p.dirname(Platform.executable);
 final String platformDill = p.join(buildDir, "vm_platform_strong.dill");
 final String genSnapshot = p.join(buildDir, "gen_snapshot${executableSuffix}");
-final String dart = p.join(buildDir, "dart${executableSuffix}");
 final String dartPrecompiledRuntime =
     p.join(buildDir, "dart_precompiled_runtime${executableSuffix}");
 final String genKernel = p.join("pkg", "vm", "bin", "gen_kernel.dart");

runtime/vm/compiler/frontend/kernel_translation_helper.cc

@@ -2654,7 +2654,18 @@ TokenPosition KernelReaderHelper::ReadPosition() {
 }
 
 intptr_t KernelReaderHelper::SourceTableFieldCountFromFirstLibraryOffset() {
-  return SourceTableFieldCountFromFirstLibraryOffset41Plus;
+  // translation_helper_.info() might not be initialized at this point so we
+  // can't use translation_helper_.info().kernel_binary_version().
+  SetOffset(KernelFormatVersionOffset);
+  uint32_t formatVersion = reader_.ReadUInt32();
+  intptr_t count_from_first_library_offset =
+      SourceTableFieldCountFromFirstLibraryOffsetPre41;
+  static_assert(kMinSupportedKernelFormatVersion < 41, "cleanup this code");
+  if (formatVersion >= 41) {
+    count_from_first_library_offset =
+        SourceTableFieldCountFromFirstLibraryOffset41Plus;
+  }
+  return count_from_first_library_offset;
 }
 
 intptr_t KernelReaderHelper::SourceTableSize() {

runtime/vm/kernel_binary.cc

@@ -15,7 +15,6 @@
 #include "vm/kernel.h"
 #include "vm/object.h"
 #include "vm/os.h"
-#include "vm/version.h"
 
 namespace dart {
 
@@ -85,14 +84,12 @@ const char* kKernelInvalidBinaryFormatVersion =
     "Invalid kernel binary format version";
 const char* kKernelInvalidSizeIndicated =
     "Invalid kernel binary: Indicated size is invalid";
-const char* kKernelInvalidSdkHash = "Invalid SDK hash";
 
 std::unique_ptr<Program> Program::ReadFrom(Reader* reader, const char** error) {
-  if (reader->size() < 70) {
+  if (reader->size() < 60) {
-    // A kernel file (v43) currently contains at least the following:
+    // A kernel file (v41) currently contains at least the following:
     //   * Magic number (32)
     //   * Kernel version (32)
-    //   * SDK Hash (10 * 8)
     //   * List of problems (8)
     //   * Length of source map (32)
     //   * Length of canonical name table (8)
@@ -101,7 +98,7 @@ std::unique_ptr<Program> Program::ReadFrom(Reader* reader, const char** error) {
     //   * Length of constant table (8)
     //   * Component index (11 * 32)
     //
-    // so is at least 74 bytes.
+    // so is at least 64 bytes.
     // (Technically it will also contain an empty entry in both source map and
     // string table, taking up another 8 bytes.)
     if (error != nullptr) {
@@ -127,18 +124,6 @@ std::unique_ptr<Program> Program::ReadFrom(Reader* reader, const char** error) {
     return nullptr;
   }
 
-  uint8_t sdkHash[11];
-  reader->ReadBytes(sdkHash, 10);
-  sdkHash[10] = 0;  // Null terminate.
-  if (strcmp(Version::SdkHash(), "0000000000") != 0 &&
-      strcmp((const char*)sdkHash, "0000000000") != 0 &&
-      strcmp((const char*)sdkHash, Version::SdkHash()) != 0) {
-    if (error != nullptr) {
-      *error = kKernelInvalidSdkHash;
-    }
-    return nullptr;
-  }
-
   std::unique_ptr<Program> program(new Program());
   program->binary_version_ = formatVersion;
   program->typed_data_ = reader->typed_data();
@@ -167,8 +152,13 @@ std::unique_ptr<Program> Program::ReadFrom(Reader* reader, const char** error) {
   // Read backwards at the end.
   program->library_count_ = reader->ReadFromIndexNoReset(
       reader->size_, LibraryCountFieldCountFromEnd, 1, 0);
+  static_assert(kMinSupportedKernelFormatVersion < 41, "cleanup this code");
   intptr_t count_from_first_library_offset =
-      SourceTableFieldCountFromFirstLibraryOffset41Plus;
+      SourceTableFieldCountFromFirstLibraryOffsetPre41;
+  if (formatVersion >= 41) {
+    count_from_first_library_offset =
+        SourceTableFieldCountFromFirstLibraryOffset41Plus;
+  }
   program->source_table_offset_ = reader->ReadFromIndexNoReset(
       reader->size_,
       LibraryCountFieldCountFromEnd + 1 + program->library_count_ + 1 +
@@ -181,9 +171,13 @@ std::unique_ptr<Program> Program::ReadFrom(Reader* reader, const char** error) {
   program->constant_table_offset_ = reader->ReadUInt32();
 
   program->main_method_reference_ = NameIndex(reader->ReadUInt32() - 1);
-  NNBDCompiledMode compilation_mode =
+  if (formatVersion >= 41) {
-      static_cast<NNBDCompiledMode>(reader->ReadUInt32());
+    NNBDCompiledMode compilation_mode =
-  program->compilation_mode_ = compilation_mode;
+        static_cast<NNBDCompiledMode>(reader->ReadUInt32());
+    program->compilation_mode_ = compilation_mode;
+  } else {
+    program->compilation_mode_ = NNBDCompiledMode::kDisabled;
+  }
 
   return program;
 }

runtime/vm/kernel_binary.h

@@ -20,8 +20,8 @@ namespace kernel {
 static const uint32_t kMagicProgramFile = 0x90ABCDEFu;
 
 // Both version numbers are inclusive.
-static const uint32_t kMinSupportedKernelFormatVersion = 43;
+static const uint32_t kMinSupportedKernelFormatVersion = 29;
-static const uint32_t kMaxSupportedKernelFormatVersion = 43;
+static const uint32_t kMaxSupportedKernelFormatVersion = 42;
 
 // Keep in sync with package:kernel/lib/binary/tag.dart
 #define KERNEL_TAG_LIST(V)                                                     \
@@ -326,12 +326,6 @@ class Reader : public ValueObject {
 
   uint8_t PeekByte() { return buffer()[offset_]; }
 
-  void ReadBytes(uint8_t* buffer, uint8_t size) {
-    for (int i = 0; i < size; i++) {
-      buffer[i] = ReadByte();
-    }
-  }
-
   bool ReadBool() { return (ReadByte() & 1) == 1; }
 
   uint8_t ReadFlags() { return ReadByte(); }

runtime/vm/kernel_loader.cc

@@ -297,11 +297,7 @@ Object& KernelLoader::LoadEntireProgram(Program* program,
     reader.set_raw_buffer(program->kernel_data() + subprogram_start);
     reader.set_size(subprogram_end - subprogram_start);
     reader.set_offset(0);
-    const char* error = nullptr;
+    std::unique_ptr<Program> subprogram = Program::ReadFrom(&reader);
-    std::unique_ptr<Program> subprogram = Program::ReadFrom(&reader, &error);
-    if (subprogram == nullptr) {
-      FATAL1("Failed to load kernel file: %s", error);
-    }
     ASSERT(subprogram->is_single_program());
     KernelLoader loader(subprogram.get(), &uri_to_source_table);
     Object& load_result = Object::Handle(loader.LoadProgram(false));
@@ -853,8 +849,7 @@ void KernelLoader::FindModifiedLibraries(Program* program,
                                          intptr_t* p_num_classes,
                                          intptr_t* p_num_procedures) {
   LongJumpScope jump;
-  Thread* thread = Thread::Current();
+  Zone* zone = Thread::Current()->zone();
-  Zone* zone = thread->zone();
   if (setjmp(*jump.Set()) == 0) {
     if (force_reload) {
       // If a reload is being forced we mark all libraries as having
@@ -899,11 +894,7 @@ void KernelLoader::FindModifiedLibraries(Program* program,
       reader.set_raw_buffer(program->kernel_data() + subprogram_start);
       reader.set_size(subprogram_end - subprogram_start);
       reader.set_offset(0);
-      const char* error = nullptr;
+      std::unique_ptr<Program> subprogram = Program::ReadFrom(&reader);
-      std::unique_ptr<Program> subprogram = Program::ReadFrom(&reader, &error);
-      if (subprogram == nullptr) {
-        FATAL1("Failed to load kernel file: %s", error);
-      }
       ASSERT(subprogram->is_single_program());
       KernelLoader loader(subprogram.get(), /*uri_to_source_table=*/nullptr);
       loader.walk_incremental_kernel(modified_libs, is_empty_program,

runtime/vm/version.h

@@ -16,13 +16,11 @@ class Version : public AllStatic {
   static const char* CommitString();
   static int CurrentAbiVersion();
   static int OldestSupportedAbiVersion();
-  static const char* SdkHash();
 
  private:
   static const char* str_;
   static const char* snapshot_hash_;
   static const char* commit_;
-  static const char* git_short_hash_;
 };
 
 }  // namespace dart

runtime/vm/version_in.cc

@@ -38,13 +38,8 @@ int Version::OldestSupportedAbiVersion() {
   return {{OLDEST_SUPPORTED_ABI_VERSION}};
 }
 
-const char* Version::SdkHash() {
-  return git_short_hash_;
-}
-
 const char* Version::snapshot_hash_ = "{{SNAPSHOT_HASH}}";
 const char* Version::str_ = "{{VERSION_STR}} ({{CHANNEL}}) ({{COMMIT_TIME}})";
 const char* Version::commit_ = "{{VERSION_STR}}";
-const char* Version::git_short_hash_ = "{{GIT_HASH}}";
 
 }  // namespace dart

sdk_args.gni

@@ -19,22 +19,4 @@ declare_args() {
   # to out/ReleaseX64/args.gn. The path above can be extracted from the `.git`
   # file under the git worktree folder.
   default_git_folder = "$_dart_root/.git"
-
-  # Whether to enable the SDK hash check that will prevent loading a kernel
-  # into a VM which was built with a different SDK.
-  verify_sdk_hash = true
-}
-
-# The SDK hash to build into VM and kernels.
-# The value 0000000000 signifies no hash is set, which will disable the check.
-if (verify_sdk_hash) {
-  sdk_hash = exec_script("$_dart_root/tools/make_version.py",
-                         [ "--format={{GIT_HASH}}" ],
-                         "trim string",
-                         [
-                           "$_dart_root/tools/VERSION",
-                           "$_dart_root/tools/utils.py",
-                         ])
-} else {
-  sdk_hash = "0000000000"
 }

tools/gn.py

@@ -136,7 +136,7 @@ def UseSysroot(args, gn_args):
     return True
 
 
-def ToGnArgs(args, mode, arch, target_os, sanitizer, verify_sdk_hash):
+def ToGnArgs(args, mode, arch, target_os, sanitizer):
     gn_args = {}
 
     host_os = HostOsForGn(HOST_OS)
@@ -258,8 +258,6 @@ def ToGnArgs(args, mode, arch, target_os, sanitizer, verify_sdk_hash):
         gn_args['dart_debug_optimization_level'] = args.debug_opt_level
         gn_args['debug_optimization_level'] = args.debug_opt_level
 
-    gn_args['verify_sdk_hash'] = verify_sdk_hash
-
     return gn_args
 
 
@@ -468,10 +466,6 @@ def parse_args(args):
         default=False,
         dest='use_qemu',
         action='store_true')
-    other_group.add_argument('--no-verify-sdk-hash',
-                             help='Disable SDK hash checks.',
-                             default=False,
-                             action='store_true')
 
     options = parser.parse_args(args)
     if not ProcessOptions(options):
@@ -512,8 +506,7 @@ def Main(argv):
                     # See dartbug.com/32364
                     command = [gn, 'gen', out_dir]
                     gn_args = ToCommandLine(
-                        ToGnArgs(args, mode, arch, target_os, sanitizer,
+                        ToGnArgs(args, mode, arch, target_os, sanitizer))
-                                 not args.no_verify_sdk_hash))
                     gn_args += GetGNArgs(args)
                     if args.verbose:
                         print("gn gen --check in %s" % out_dir)

tools/make_version.py

@@ -7,13 +7,19 @@
 
 from __future__ import print_function
 
-import argparse
 import hashlib
 import os
 import sys
 import time
+from optparse import OptionParser
 import utils
 
+
+def debugLog(message):
+    print(message, file=sys.stderr)
+    sys.stderr.flush()
+
+
 # When these files change, snapshots created by the VM are potentially no longer
 # backwards-compatible.
 VM_SNAPSHOT_FILES = [
@@ -39,141 +45,142 @@ VM_SNAPSHOT_FILES = [
 ]
 
 
+def MakeVersionString(quiet, no_git_hash, custom_for_pub=None):
+    channel = utils.GetChannel()
+
+    if custom_for_pub and channel == 'be':
+        latest = utils.GetLatestDevTag()
+        if not latest:
+            # If grabbing the dev tag fails, then fall back on the VERSION file.
+            latest = utils.GetSemanticSDKVersion(no_git_hash=True)
+        if no_git_hash:
+            version_string = ("%s.%s" % (latest, custom_for_pub))
+        else:
+            git_hash = utils.GetShortGitHash()
+            version_string = ("%s.%s-%s" % (latest, custom_for_pub, git_hash))
+    else:
+        version_string = utils.GetSemanticSDKVersion(no_git_hash=no_git_hash)
+    if not quiet:
+        debugLog("Returning version string: %s " % version_string)
+    return version_string
+
+
 def MakeSnapshotHashString():
     vmhash = hashlib.md5()
     for vmfilename in VM_SNAPSHOT_FILES:
         vmfilepath = os.path.join(utils.DART_DIR, 'runtime', 'vm', vmfilename)
-        with open(vmfilepath, 'rb') as vmfile:
+        with open(vmfilepath) as vmfile:
-            vmhash.update(vmfile.read())
+            vmhash.update(vmfile.read().encode('utf-8'))
     return vmhash.hexdigest()
 
 
-def GetSemanticVersionFormat(no_git_hash, custom_for_pub):
+def MakeFile(quiet,
-    version_format = '{{SEMANTIC_SDK_VERSION}}'
+             output_file,
-
+             input_file,
-    if custom_for_pub and utils.GetChannel() == 'be':
+             no_git_hash,
-        if no_git_hash:
+             custom_for_pub,
-            version_format = '{{LATEST}}.{{PUB_CUSTOM}}'
+             version_file=None):
-        else:
+    if version_file:
-            version_format = '{{LATEST}}.{{PUB_CUSTOM}}-{{GIT_HASH}}'
+        version_string = utils.GetVersion(no_git_hash, version_file)
-
+    else:
-    return version_format
+        version_string = MakeVersionString(quiet, no_git_hash, custom_for_pub)
-
-
-def FormatVersionString(version,
-                        no_git_hash,
-                        custom_for_pub,
-                        version_file=None,
-                        git_revision_file=None):
-    semantic_sdk_version = utils.GetSemanticSDKVersion(no_git_hash,
-                                                       version_file,
-                                                       git_revision_file)
-    semantic_version_format = GetSemanticVersionFormat(no_git_hash,
-                                                       custom_for_pub)
-    version_str = (semantic_sdk_version
-                   if version_file else semantic_version_format)
-
-    version = version.replace('{{VERSION_STR}}', version_str)
-
-    version = version.replace('{{SEMANTIC_SDK_VERSION}}', semantic_sdk_version)
-
-    # If grabbing the dev tag fails, then fall back on the default VERSION file.
-    latest = utils.GetLatestDevTag()
-    if not latest:
-        utils.GetSemanticSDKVersion(no_git_hash=True)
-    version = version.replace('{{LATEST}}', latest)
-
-    if custom_for_pub:
-        version = version.replace('{{PUB_CUSTOM}}', custom_for_pub)
-
-    git_hash = utils.GetShortGitHash()
-    if git_hash is None or len(git_hash) != 10:
-        git_hash = '0000000000'
-    version = version.replace('{{GIT_HASH}}', git_hash)
 
+    version_cc_text = open(input_file).read()
+    version_cc_text = version_cc_text.replace("{{VERSION_STR}}", version_string)
     channel = utils.GetChannel()
-    version = version.replace('{{CHANNEL}}', channel)
+    version_cc_text = version_cc_text.replace("{{CHANNEL}}", channel)
-
     version_time = utils.GetGitTimestamp()
     if no_git_hash or version_time == None:
-        version_time = 'Unknown timestamp'
+        version_time = "Unknown timestamp"
-    version = version.replace('{{COMMIT_TIME}}', version_time.decode('utf-8'))
+    version_cc_text = version_cc_text.replace("{{COMMIT_TIME}}",
-
+                                              version_time.decode("utf-8"))
     abi_version = utils.GetAbiVersion(version_file)
-    version = version.replace('{{ABI_VERSION}}', abi_version)
+    version_cc_text = version_cc_text.replace("{{ABI_VERSION}}", abi_version)
-
     oldest_supported_abi_version = utils.GetOldestSupportedAbiVersion(
         version_file)
-    version = version.replace('{{OLDEST_SUPPORTED_ABI_VERSION}}',
+    version_cc_text = version_cc_text.replace(
-                              oldest_supported_abi_version)
+        "{{OLDEST_SUPPORTED_ABI_VERSION}}", oldest_supported_abi_version)
-
     snapshot_hash = MakeSnapshotHashString()
-    version = version.replace('{{SNAPSHOT_HASH}}', snapshot_hash)
+    version_cc_text = version_cc_text.replace("{{SNAPSHOT_HASH}}",
-
+                                              snapshot_hash)
-    return version
+    open(output_file, 'w').write(version_cc_text)
+    return True
 
 
-def main():
+def main(args):
     try:
         # Parse input.
-        parser = argparse.ArgumentParser()
+        parser = OptionParser()
-        parser.add_argument(
+        parser.add_option(
-            '--custom_for_pub',
+            "--custom_for_pub",
-            help=('Generates a version string that works with pub that '
+            action="store",
-                  'includes the given string. This is silently ignored on '
+            type="string",
-                  'channels other than be.'))
+            help=("Generates a version string that works with pub that includes"
-        parser.add_argument('--input', help='Input template file.')
+                  "the given string. This is silently ignored on channels other"
-        parser.add_argument('--no_git_hash',
+                  "than be"))
-                            action='store_true',
+        parser.add_option(
-                            default=False,
+            "--input",
-                            help='Don\'t try to determine VCS revision.')
+            action="store",
-        parser.add_argument('--output', help='output file name')
+            type="string",
-        parser.add_argument('-q',
+            help="input template file.")
-                            '--quiet',
+        parser.add_option(
-                            action='store_true',
+            "--no_git_hash",
-                            default=False,
+            action="store_true",
-                            help='DEPRECATED: Does nothing!')
+            default=False,
-        parser.add_argument('--version-file', help='Path to the VERSION file.')
+            help="Don't try to determine svn revision")
-        parser.add_argument('--git-revision-file',
+        parser.add_option(
-                            help='Path to the GIT_REVISION file.')
+            "--output", action="store", type="string", help="output file name")
-        parser.add_argument(
+        parser.add_option(
-            '--format',
+            "-q",
-            default='{{VERSION_STR}}',
+            "--quiet",
-            help='Version format used if no input template is given.')
+            action="store_true",
+            default=False,
+            help="disable console output")
+        parser.add_option(
+            "--version-file",
+            action="store",
+            type="string",
+            default=None,
+            help="Version file")
 
-        args = parser.parse_args()
+        (options, args) = parser.parse_args()
 
         # If there is no input template, then write the bare version string to
-        # args.output. If there is no args.output, then write the version
+        # options.output. If there is no options.output, then write the version
         # string to stdout.
+        if not options.input:
+            version_string = MakeVersionString(
+                options.quiet, options.no_git_hash, options.custom_for_pub)
+            if options.output:
+                open(options.output, 'w').write(version_string)
+            else:
+                print(version_string)
+            return 0
 
-        version_template = ''
+        if not options.output:
-        if args.input:
+            sys.stderr.write('--output not specified\n')
-            version_template = open(args.input).read()
+            return -1
-        elif not args.format is None:
+        if not options.input:
-            version_template = args.format
+            sys.stderr.write('--input not specified\n')
-        else:
+            return -1
-            raise 'No version template given! Set either --input or --format.'
 
-        version = FormatVersionString(version_template, args.no_git_hash,
+        files = []
-                                      args.custom_for_pub, args.version_file,
+        for arg in args:
-                                      args.git_revision_file)
+            files.append(arg)
 
-        if args.output:
+        if not MakeFile(options.quiet, options.output, options.input,
-            with open(args.output, 'w') as fh:
+                        options.no_git_hash, options.custom_for_pub,
-                fh.write(version)
+                        options.version_file):
-        else:
+            return -1
-            sys.stdout.write(version)
 
         return 0
-
     except Exception as inst:
         sys.stderr.write('make_version.py exception\n')
         sys.stderr.write(str(inst))
         sys.stderr.write('\n')
-
         return -1
 
 
 if __name__ == '__main__':
-    sys.exit(main())
+    exit_code = main(sys.argv)
+    sys.exit(exit_code)

tools/utils.py

@@ -350,16 +350,13 @@ def GetShortVersion():
                                 version.prerelease, version.prerelease_patch))
 
 
-def GetSemanticSDKVersion(no_git_hash=False,
+def GetSemanticSDKVersion(no_git_hash=False, version_file=None):
-                          version_file=None,
-                          git_revision_file=None):
     version = ReadVersionFile(version_file)
     if not version:
         return None
 
     if version.channel == 'be':
-        postfix = '-edge' if no_git_hash else '-edge.%s' % GetGitRevision(
+        postfix = '-edge' if no_git_hash else '-edge.%s' % GetGitRevision()
-            git_revision_file)
     elif version.channel in ('beta', 'dev'):
         postfix = '-%s.%s.%s' % (version.prerelease, version.prerelease_patch,
                                  version.channel)
@@ -370,8 +367,8 @@ def GetSemanticSDKVersion(no_git_hash=False,
     return '%s.%s.%s%s' % (version.major, version.minor, version.patch, postfix)
 
 
-def GetVersion(no_git_hash=False, version_file=None, git_revision_file=None):
+def GetVersion(no_git_hash=False, version_file=None):
-    return GetSemanticSDKVersion(no_git_hash, version_file, git_revision_file)
+    return GetSemanticSDKVersion(no_git_hash, version_file)
 
 
 # The editor used to produce the VERSION file put on gcs. We now produce this
@@ -470,13 +467,12 @@ def GetArchiveVersion():
     return GetSemanticSDKVersion()
 
 
-def GetGitRevision(git_revision_file=None):
+def GetGitRevision():
     # When building from tarball use tools/GIT_REVISION
-    if git_revision_file is None:
+    git_revision_file = os.path.join(DART_DIR, 'tools', 'GIT_REVISION')
-        git_revision_file = os.path.join(DART_DIR, 'tools', 'GIT_REVISION')
     try:
         with open(git_revision_file) as fd:
-            return fd.read().strip()
+            return fd.read()
     except:
         pass
     p = subprocess.Popen(['git', 'rev-parse', 'HEAD'],

utils/application_snapshot.gni

@@ -98,11 +98,9 @@ template("_application_snapshot") {
     depfile = "$output.d"
     abs_depfile = rebase_path(depfile)
     rebased_output = rebase_path(output, root_build_dir)
-
     vm_args = [
       "--depfile=$abs_depfile",
       "--depfile_output_filename=$rebased_output",
-      "-Dsdk_hash=$sdk_hash",
     ]
 
     script = gen_kernel_script

utils/compile_platform.gni

@@ -3,7 +3,6 @@
 # BSD-style license that can be found in the LICENSE file.
 
 import("../build/dart/dart_action.gni")
-import("../sdk_args.gni")
 
 _dart_root = get_path_info("..", "abspath")
 
@@ -47,8 +46,6 @@ template("compile_platform") {
 
     outputs = invoker.outputs
 
-    vm_args = [ "-Dsdk_hash=$sdk_hash" ]
-
     inputs = []
     deps = []
     args = []

utils/dartanalyzer/BUILD.gn

@@ -44,7 +44,6 @@ prebuilt_dart_action("generate_summary_strong") {
   inputs = sdk_lib_files + analyzer_files
   output = "$root_gen_dir/strong.sum"
   outputs = [ output ]
-  vm_args = [ "-Dsdk_hash=$sdk_hash" ]
   args = [
     "build",
     rebase_path(output),

utils/dartdevc/BUILD.gn

@@ -82,8 +82,6 @@ template("dart2js_compile") {
 
     packages = "../../.packages"
 
-    vm_args = [ "-Dsdk_hash=$sdk_hash" ]
-
     args = [
       "$abs_main",
       "-m",
@@ -120,8 +118,6 @@ prebuilt_dart_action("dartdevc_patch_sdk") {
   # TODO(rnystrom): List the outputs more precisely?
   outputs = [ "$patched_sdk_dir/version" ]
 
-  vm_args = [ "-Dsdk_hash=$sdk_hash" ]
-
   args = [
     "--libraries",
     rebase_path("$sdk_root/lib/libraries.json"),
@@ -234,8 +230,6 @@ template("dartdevc_kernel_compile") {
       "$js_gen_dir/$module.js",
     ]
 
-    vm_args = [ "-Dsdk_hash=$sdk_hash" ]
-
     args = [
       "-k",
       "--dart-sdk-summary=$sdk_path",
@@ -390,8 +384,6 @@ template("dartdevc_sdk_js") {
       "$js_gen_dir/legacy/dart_sdk.js.map",
     ]
 
-    vm_args = [ "-Dsdk_hash=$sdk_hash" ]
-
     script = "../../pkg/dev_compiler/bin/dartdevc.dart"
 
     args = [

utils/kernel-service/BUILD.gn

@@ -85,11 +85,9 @@ template("kernel_service_dill") {
     depfile = "$root_gen_dir/kernel_service" + invoker.target_name + "_dill.d"
     abs_depfile = rebase_path(depfile)
     rebased_output = rebase_path(output, root_build_dir)
-
     vm_args = [
       "--depfile=$abs_depfile",
       "--depfile_output_filename=$rebased_output",
-      "-Dsdk_hash=$sdk_hash",
     ]
 
     script = gen_kernel_script