[kernel] Delete most of the AST

pkg/kernel/lib/binary/ast_from_binary.dart

Index: pkg/kernel/lib/binary/ast_from_binary.dart
diff --git a/pkg/kernel/lib/binary/ast_from_binary.dart b/pkg/kernel/lib/binary/ast_from_binary.dart
index f0c34cd1dab49c9515f8e8d54d17baa8b22fc2a0..3f4d454bea920b509248031006af78cd77553f1f 100644
--- a/pkg/kernel/lib/binary/ast_from_binary.dart
+++ b/pkg/kernel/lib/binary/ast_from_binary.dart
@@ -68,7 +68,7 @@ class BinaryBuilder {
     }
   }
 
-  int readMagicWord() {
+  int readUint32() {
     return (readByte() << 24) |
         (readByte() << 16) |
         (readByte() << 8) |
@@ -237,7 +237,7 @@ class BinaryBuilder {
     _readOneProgram(program);
     if (_byteIndex < _bytes.length) {
       if (_byteIndex + 3 < _bytes.length) {
-        int magic = readMagicWord();
+        int magic = readUint32();
         if (magic == Tag.ProgramFile) {
           throw 'Concatenated program file given when a single program '
               'was expected.';
@@ -248,7 +248,7 @@ class BinaryBuilder {
   }
 
   void _readOneProgram(Program program) {
-    int magic = readMagicWord();
+    int magic = readUint32();
     if (magic != Tag.ProgramFile) {
       throw fail('This is not a binary dart file. '
           'Magic number was: ${magic.toRadixString(16)}');
@@ -264,6 +264,16 @@ class BinaryBuilder {
     }
     var mainMethod = readMemberReference(allowNull: true);
     program.mainMethodName ??= mainMethod;
+    readUint32(); // binary offset for source table.
+    readUint32(); // binary offset for link table.
+    readUint32(); // main
+    for (int i = 0; i < numberOfLibraries; i++) {
+      readUint32(); // binary offset for library #i.
+    }
+    int numberOfLibrariesCheck = readUint32();
+    if (numberOfLibraries != numberOfLibrariesCheck) {
+      throw "Expected number of libraries to match!";

[Kevin Millikin (Google), 2017/06/29 12:27:36]

Even if you're just throwing a string and not some structured exception, make it
informative.  Something like:

'Malformed binary: the table of contents indicates there are
$numberOfLibrariesCheck libraries but the binary contains $numberOfLibraries.'

Perhaps we can also throw if there is anything else (add a method to the reader
that reports if it is at the end of the stream).

[jensj, 2017/06/30 05:51:17]

I'm not sure about throwing if we're not at the end --- readProgram indicates
that we can have several programs in the same dill file, though I'm not sure
when that's applicable?

+    }
   }
 
   Map<String, Source> readUriToSource() {