[clang][Parse] properly parse asm-qualifiers, asm inline

Summary:
The parsing of GNU C extended asm statements was a little brittle and
had a few issues:
- It was using Parse::ParseTypeQualifierListOpt to parse the `volatile`
  qualifier.  That parser is really meant for TypeQualifiers; an asm
  statement doesn't really have a type qualifier. This is still maybe
  nice to have, but not necessary. We now can check for the `volatile`
  token by properly expanding the grammer, rather than abusing
  Parse::ParseTypeQualifierListOpt.
- The parsing of `goto` was position dependent, so `asm goto volatile`
  wouldn't parse. The qualifiers should be position independent to one
  another. Now they are.
- We would warn on duplicate `volatile`, but the parse error for
  duplicate `goto` was a generic parse error and wasn't clear.
- We need to add support for the recent GNU C extension `asm inline`.
  Adding support to the parser with the above issues highlighted the
  need for this refactoring.

Link: https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html

Reviewers: aaron.ballman

Reviewed By: aaron.ballman

Subscribers: aheejin, jfb, nathanchance, cfe-commits, echristo, efriedma, rsmith, chandlerc, craig.topper, erichkeane, jyu2, void, srhines

Tags: #clang

Differential Revision: https://reviews.llvm.org/D75563

1 files changed, 5 insertions, 5 deletions

diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index ffe31f8..27cb8a2 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -1529,13 +1529,13 @@ ExprResult Parser::ParseSimpleAsm(bool ForAsmLabel, SourceLocation *EndLoc) {
   assert(Tok.is(tok::kw_asm) && "Not an asm!");
   SourceLocation Loc = ConsumeToken();
 
-  if (Tok.is(tok::kw_volatile)) {
-    // Remove from the end of 'asm' to the end of 'volatile'.
+  if (isGNUAsmQualifier(Tok)) {
+    // Remove from the end of 'asm' to the end of the asm qualifier.
     SourceRange RemovalRange(PP.getLocForEndOfToken(Loc),
                              PP.getLocForEndOfToken(Tok.getLocation()));
-
-    Diag(Tok, diag::warn_file_asm_volatile)
-      << FixItHint::CreateRemoval(RemovalRange);
+    Diag(Tok, diag::err_global_asm_qualifier_ignored)
+        << GNUAsmQualifiers::getQualifierName(getGNUAsmQualifier(Tok))
+        << FixItHint::CreateRemoval(RemovalRange);
     ConsumeToken();
   }