Remove support for EXPORTAS in def files to maintain ABI compatibility for COFFShortExport

Author: dpaoliello

llvm/include/llvm/Object/COFFImportFile.h

@@ -104,10 +104,6 @@ struct COFFShortExport {
   /// file, this is "baz" in "EXPORTS\nfoo = bar == baz".
   std::string ImportName;
 
-  /// Specifies EXPORTAS name. In a .def file, this is "bar" in
-  /// "EXPORTS\nfoo EXPORTAS bar".
-  std::string ExportAs;
-
   uint16_t Ordinal = 0;
   bool Noname = false;
   bool Data = false;

llvm/lib/Object/COFFModuleDefinition.cpp

@@ -39,7 +39,6 @@ enum Kind {
   KwConstant,
   KwData,
   KwExports,
-  KwExportAs,
   KwHeapsize,
   KwLibrary,
   KwName,
@@ -117,7 +116,6 @@ class Lexer {
                    .Case("CONSTANT", KwConstant)
                    .Case("DATA", KwData)
                    .Case("EXPORTS", KwExports)
-                   .Case("EXPORTAS", KwExportAs)
                    .Case("HEAPSIZE", KwHeapsize)
                    .Case("LIBRARY", KwLibrary)
                    .Case("NAME", KwName)
@@ -284,16 +282,7 @@ class Parser {
         E.ImportName = std::string(Tok.Value);
         continue;
       }
-      // EXPORTAS must be at the end of export definition
-      if (Tok.K == KwExportAs) {
-        read();
-        if (Tok.K == Eof)
-          return createError(
-              "unexpected end of file, EXPORTAS identifier expected");
-        E.ExportAs = std::string(Tok.Value);
-      } else {
-        unget();
-      }
+      unget();
       Info.Exports.push_back(E);
       return Error::success();
     }