DataCount section (#2006)

* DataCount section

Read the DataCount section and verify that it agrees with the data
section. Also emit the DataCount section when bulk-memory is enabled
and there are a nonzero number of segments. Factor out some shared
unit test code.

1 files changed, 9 insertions, 1 deletions

diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index 50b78fbae..1f6222cba 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -322,7 +322,8 @@ enum Section {
   Start = 8,
   Element = 9,
   Code = 10,
-  Data = 11
+  Data = 11,
+  DataCount = 12,
 };
 
 enum SegmentFlag {
@@ -891,6 +892,7 @@ public:
   void writeFunctions();
   void writeGlobals();
   void writeExports();
+  void writeDataCount();
   void writeDataSegments();
 
   std::unordered_map<Name, Index> mappedFunctions; // name of the Function => index. first imports, then internals
@@ -1083,8 +1085,14 @@ public:
   std::map<Index, Name> mappedGlobals; // index of the Global => name. first imported globals, then internal globals
 
   Name getGlobalName(Index index);
+  void validateBinary(); // validations that cannot be performed on the Module
   void processFunctions();
+
+  size_t dataCount = 0;
+  bool hasDataCount = false;
+
   void readDataSegments();
+  void readDataCount();
 
   std::map<Index, std::vector<Index>> functionTable;