[COFF] Support ordinals in def files with space between @ and the number

[mstorsjo]

Summary

Both GNU ld and MS link.exe support declaring ordinals this way.

A test will be added in lld.

[rnk]

lib/Object/COFFModuleDefinition.cpp

253 ↗

(On Diff #120381)

Please add a comment describing the three alternatives:

foo@10
foo @ 10
foo\n@bar

Otherwise, looks good.

llvm/trunk/lib/Object/COFFModuleDefinition.cpp

if (Machine == IMAGE_FILE_MACHINE_I386) {
         E.Name = (std::string("_").append(E.Name));
       if (!E.ExtName.empty() && !isDecorated(E.ExtName, MingwDef))
         E.ExtName = (std::string("_").append(E.ExtName));
     }
 
     for (;;) {
       read();
       if (Tok.K == Identifier && Tok.Value[0] == '@') {
-        if (Tok.Value.drop_front().getAsInteger(10, E.Ordinal)) {
-          // Not an ordinal modifier at all, but the next export (fastcall
-          // decorated) - complete the current one.
+        if (Tok.Value == "@") {
+          // "foo @ 10"
+          read();
+          Tok.Value.getAsInteger(10, E.Ordinal);
+        } else if (Tok.Value.drop_front().getAsInteger(10, E.Ordinal)) {
+          // "foo \n @bar" - Not an ordinal modifier at all, but the next
+          // export (fastcall decorated) - complete the current one.
           unget();
           Info.Exports.push_back(E);
           return Error::success();
         }
+        // "foo @10"
         read();
         if (Tok.K == KwNoname) {
           E.Noname = true;
         } else {
           unget();
         }
         continue;
       }