[MC] - Stop ignoring invalid meta data symbols.

[grimar]

Summary

Previously llvm-mc would silently accept code from testcase,
that contains invalid metadata symbol in section declaration.

Patch fixes the issue.

[grimar]

Accepted by Rafael in mail list.

lib/MC/MCParser/ELFAsmParser.cpp

 
 bool ELFAsmParser::parseMetadataSym(MCSymbolELF *&Associated) {
   MCAsmLexer &L = getLexer();
   if (L.isNot(AsmToken::Comma))
     return TokError("expected metadata symbol");
   Lex();
   StringRef Name;
   if (getParser().parseIdentifier(Name))
-    return true;
+    return TokError("invalid metadata symbol");
   Associated = dyn_cast_or_null<MCSymbolELF>(getContext().lookupSymbol(Name));
   if (!Associated || !Associated->isInSection())
     return TokError("symbol is not in a section: " + Name);
   return false;
 }
 
 bool ELFAsmParser::maybeParseUniqueID(int64_t &UniqueID) {
   MCAsmLexer &L = getLexer();

test/MC/ELF/metadata-declaration-errors.s

+// RUN: not llvm-mc -triple x86_64-pc-linux-gnu %s \
+// RUN:   -filetype=obj -o %t.o 2>&1 | FileCheck %s
+
+// Check we do not silently ignore invalid metadata symbol (123).
+// CHECK: error: invalid metadata symbol
+
+.section .foo,"a"
+.quad 0
+
+.section bar,"ao",@progbits,123