[kernel] Read constant table before deserializing metadata in BinaryBuilder.

Change-Id: Icf5d22e32eefb371c4b60d4039ab0455181450b5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/421360
Reviewed-by: Jens Johansen <[email protected]>
Commit-Queue: Nate Biggs <[email protected]>

Author: natebiggs

pkg/kernel/lib/binary/ast_from_binary.dart

@@ -890,12 +890,6 @@ class BinaryBuilder {
     _byteOffset = index.binaryOffsetForCanonicalNames;
     readLinkTable(component.root);
 
-    // TODO(alexmarkov): reverse metadata mappings and read forwards
-    _byteOffset = index.binaryOffsetForStringTable; // Read backwards.
-    _readMetadataMappings(component, index.binaryOffsetForMetadataPayloads);
-
-    _associateMetadata(component, _componentStartOffset);
-
     _byteOffset = index.binaryOffsetForSourceTable;
     Map<Uri, Source> uriToSource = readUriToSource(readCoverage: true);
     _mergeUriToSource(component.uriToSource, uriToSource);
@@ -904,6 +898,14 @@ class BinaryBuilder {
     readConstantTable();
     // We don't need the constant table index on the dart side.
 
+    // TODO(alexmarkov): reverse metadata mappings and read forwards
+    // Ensure constant table is loaded before metadata is read as it may contain
+    // references to the constant table.
+    _byteOffset = index.binaryOffsetForStringTable; // Read backwards.
+    _readMetadataMappings(component, index.binaryOffsetForMetadataPayloads);
+
+    _associateMetadata(component, _componentStartOffset);
+
     int numberOfLibraries = index.libraryCount;
 
     SubComponentView? result;