+ read the data count from the data section. Set size of the DataSegments

  array, if the data count section hasn't been encountered. Compare the count
  with the value from the data count section, in case the data count section
  has been encountered, and issue an error, if they differ.

compiler/ogwasm.pas

@@ -2731,6 +2731,8 @@ implementation
           end;
 
         function ReadDataSection: Boolean;
+          var
+            DataCount: uint32;
           begin
             Result:=False;
             if DataSectionRead then
@@ -2739,6 +2741,21 @@ implementation
                 exit;
               end;
             DataSectionRead:=True;
+            if not ReadUleb32(DataCount) then
+              begin
+                InputError('Error reading the data entries count from the data section');
+                exit;
+              end;
+            if DataCountSectionRead then
+              begin
+                if Length(DataSegments)<>DataCount then
+                  begin
+                    InputError('Data entries count in the data section do not match the number, specified in the data count section');
+                    exit
+                  end;
+              end
+            else
+              SetLength(DataSegments,DataCount);
           end;
 
         function ReadDataCountSection: Boolean;