VM support for running Kernel binaries.

runtime/bin/dartutils.h

Index: runtime/bin/dartutils.h
diff --git a/runtime/bin/dartutils.h b/runtime/bin/dartutils.h
index b9fe476e0acf9dac2f1c2604fa7aac61e1b8f44c..8815a1cf165a3ea82ea512ec553ac1df3908ed8a 100644
--- a/runtime/bin/dartutils.h
+++ b/runtime/bin/dartutils.h
@@ -33,6 +33,15 @@ static inline Dart_Handle ThrowIfError(Dart_Handle handle) {
   return handle;
 }
 
+// Tries to read [script_uri] as a Kernel IR file.  If successful this function
+// returns `true` and sets [dil_file] and [dil_length] to be the memory
+// contents.
+//
+// The caller is responsible for free()ing [dil_file] if `true` was returned.
+bool TryReadKernel(const char* script_uri,

[rmacnak, 2016/10/13 00:56:39]

General question: Why does the embedder code call this "Kernel" but the vm code
calls this "DIL"?

[Kevin Millikin (Google), 2016/10/13 04:29:40]

It mostly historical.  We called it DIL (Dart Intermediate Language) until we
came up with the name Kernel which is better.

At one point I started changing references to DIL but mkustermann@ argued
against doing it at that time.  This is probably the time.  We do like the
namespace name dil because it's so short.  (We've toyed with the ides that we
could have a name for the IR's tree representation (Kernel) and another name for
its binary format (DIL), but I don't really think that's an important
distinction.)

[Vyacheslav Egorov (Google), 2016/10/13 14:37:57]

Renamed all DIL to Kernel.

+                   const uint8_t** dil_file,
+                   intptr_t* dil_length);
+
 class CommandLineOptions {
  public:
   explicit CommandLineOptions(int max_count)
@@ -200,14 +209,21 @@ class DartUtils {
   static Dart_Handle ResolveUriInWorkingDirectory(Dart_Handle script_uri);
   static Dart_Handle ResolveScript(Dart_Handle url);
 
+  enum MagicNumber {
+    kSnapshotMagicNumber,
+    kKernelMagicNumber,
+    kUnknownMagicNumber
+  };
+
+  // static const uint8_t* GetMagicNumber(MagicNumber number);
+
   // Sniffs the specified text_buffer to see if it contains the magic number
   // representing a script snapshot. If the text_buffer is a script snapshot
   // the return value is an updated pointer to the text_buffer pointing past
   // the magic number value. The 'buffer_len' parameter is also appropriately
   // adjusted.
-  static const uint8_t* SniffForMagicNumber(const uint8_t* text_buffer,
-                                            intptr_t* buffer_len,
-                                            bool* is_snapshot);
+  static MagicNumber SniffForMagicNumber(const uint8_t** text_buffer,
+                                         intptr_t* buffer_len);
 
   // Write a magic number to indicate a script snapshot file.
   static void WriteMagicNumber(File* file);
@@ -231,8 +247,6 @@ class DartUtils {
   static const char* const kHttpScheme;
   static const char* const kVMServiceLibURL;
 
-  static const uint8_t magic_number[];
-
   static Dart_Handle LibraryFilePath(Dart_Handle library_uri);
 
  private: