Handle EOL preprocessor comments for ELFAsmParser symbol attr directives

[tejohnson]

Summary

There is already handling in the MCAsmParser for end-of-line comments
starting with "#". This is handled in MCAsmParser::parseOptionalToken,
which is invoked by MCAsmParser::parseMany which parses comma-separated
lists. However, the ELFAsmParser was not invoking this handling.

I found this issue when adding .global/.globl to the set of directives
handled by the ELFAsmParser for a different change, which caused the
test/MC/AsmParser/AArch64/directive-parse-err.s to fail to parse:

.global a2                   # EOL COMMENT

This is because the ELFAsmParser was then invoked to handle parsing
of this directive, instead of falling through to the invocation of
AsmParser::parseDirectiveSymbolAttribute (which invokes parseMany) in
AsmParser::parseStatement.

In this patch I add a test case to show the failure for a symbol
directive already processed by ELFAsmParser (.hidden), and modify
the parser to invoke parseMany.

lib/MC/MCParser/ELFAsmParser.cpp

bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
   MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
     .Case(".weak", MCSA_Weak)
     .Case(".local", MCSA_Local)
     .Case(".hidden", MCSA_Hidden)
     .Case(".internal", MCSA_Internal)
     .Case(".protected", MCSA_Protected)
     .Default(MCSA_Invalid);
   assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
-  if (getLexer().isNot(AsmToken::EndOfStatement)) {
-    while (true) {
-      StringRef Name;
-
-      if (getParser().parseIdentifier(Name))
-        return TokError("expected identifier in directive");
-
-      MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
-
-      getStreamer().EmitSymbolAttribute(Sym, Attr);
+  auto parseOp = [&]() -> bool {
+      return true;
+    return false;
+  };
 
-      if (getLexer().is(AsmToken::EndOfStatement))
-        break;
-
-      if (getLexer().isNot(AsmToken::Comma))
-        return TokError("unexpected token in directive");
-      Lex();
-    }
-  }
+  if (parseMany(parseOp))
+    return addErrorSuffix(" in '" + Twine(Directive) + "' directive");
 
-  Lex();
   return false;
 }
 
 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
                                       unsigned Flags, SectionKind Kind) {
   const MCExpr *Subsection = nullptr;
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     if (getParser().parseExpression(Subsection))

test/MC/AsmParser/AArch64/directive-parse-err.s

 // RUN: not llvm-mc -triple aarch64-unknown-unknown %s 2>&1 | FileCheck %s
-// RUN: not llvm-mc -triple aarch64-unknown-unknown %s 2>&1 | grep "error:" | count 60
+// RUN: not llvm-mc -triple aarch64-unknown-unknown %s 2>&1 | grep "error:" | count 61
 
   // CHECK: [[@LINE+1]]:19: error: unexpected token in '.equ' directive
   .equ   ident1, 0 $
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   .equ   ident1, 0 # EOL COMMENT
   // CHECK: [[@LINE+1]]:19: error: unexpected token in '.equiv' directive
   .equiv ident2, 0 $
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
// RUN: not llvm-mc -triple aarch64-unknown-unknown %s 2>&1 | grep "error:" | count 61
   // CHECK: [[@LINE+1]]:31: error: unexpected token
   .globl a1                    $
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   .globl a1                    # EOL COMMENT
   // CHECK: [[@LINE+1]]:31: error: unexpected token in directive
   .global a2                   $
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   .global a2                   # EOL COMMENT
+  // CHECK: [[@LINE+1]]:31: error: unexpected token
+  .hidden a1                   $
+  // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
+  .hidden a1                   # EOL COMMENT
   // CHECK: [[@LINE+1]]:31: error: unexpected token in directive
   .lazy_reference a3           $
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   .lazy_reference a3           # EOL COMMENT
   // CHECK: [[@LINE+1]]:31: error: unexpected token in directive
   .symbol_resolver a4          $
   // CHECK-NOT: [[@LINE+1]]:{{[0-9]+}}: error:
   .symbol_resolver a4          # EOL COMMENT