Allow AsmLabel with -fno-gnu-inline-asm

Summary:
AsmLabel is heavily used in system level and firmware to redirect
function and access platform specific labels. They are also extensively
used in system headers which makes this option unusable for many
users. Since AsmLabel doesn't introduce any assembly code into the
output binary, it shouldn't be considered as inline-asm.

Reviewers: bob.wilson, rnk

Reviewed By: rnk

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D9679

llvm-svn: 237048

Author: cachemeifyoucan

clang/lib/Parse/Parser.cpp

@@ -669,6 +669,11 @@ Parser::ParseExternalDeclaration(ParsedAttributesWithRange &attrs,
 
     SourceLocation StartLoc = Tok.getLocation();
     SourceLocation EndLoc;
+
+    // Check if GNU-style InlineAsm is disabled.
+    if (!getLangOpts().GNUAsm)
+      Diag(StartLoc, diag::err_gnu_inline_asm_disabled);
+
     ExprResult Result(ParseSimpleAsm(&EndLoc));
 
     ExpectAndConsume(tok::semi, diag::err_expected_after,
@@ -1253,10 +1258,6 @@ ExprResult Parser::ParseSimpleAsm(SourceLocation *EndLoc) {
   assert(Tok.is(tok::kw_asm) && "Not an asm!");
   SourceLocation Loc = ConsumeToken();
 
-  // Check if GNU-style InlineAsm is disabled.
-  if (!getLangOpts().GNUAsm)
-    Diag(Loc, diag::err_gnu_inline_asm_disabled);
-
   if (Tok.is(tok::kw_volatile)) {
     // Remove from the end of 'asm' to the end of 'volatile'.
     SourceRange RemovalRange(PP.getLocForEndOfToken(Loc),

clang/test/Parser/no-gnu-inline-asm.c

@@ -1,6 +1,10 @@
 // RUN: %clang_cc1 %s -triple i686-apple-darwin -verify -fsyntax-only -fno-gnu-inline-asm
 
 asm ("INST r1, 0"); // expected-error {{GNU-style inline assembly is disabled}}
+
+void foo() __asm("__foo_func"); // AsmLabel is OK
+int foo1 asm("bar1") = 0; // OK
+
 void f (void) {
   long long foo = 0, bar;
   asm volatile("INST %0, %1" : "=r"(foo) : "r"(bar)); // expected-error {{GNU-style inline assembly is disabled}}