[clang] ef3800e - Return false from __has_declspec_attribute() if not explicitly enabled

[Aaron Ballman via cfe-commits]

Author: Timm Bäder
Date: 2021-01-12T13:20:08-05:00
New Revision: ef3800e82169c674219501d9ac09ef12b28e6359

URL: https://github.com/llvm/llvm-project/commit/ef3800e82169c674219501d9ac09ef12b28e6359
DIFF: https://github.com/llvm/llvm-project/commit/ef3800e82169c674219501d9ac09ef12b28e6359.diff

LOG: Return false from __has_declspec_attribute() if not explicitly enabled

Currently, projects can check for __has_declspec_attribute() and use
it accordingly, but the check for __has_declspec_attribute will return
true even if declspec attributes are not enabled for the target.

This changes Clang to instead return false when declspec attributes are
not supported for the target.

Added: 
    

Modified: 
    clang/lib/Lex/PPMacroExpansion.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 3969630f2002..43d31d6c5732 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -1693,8 +1693,14 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
       [this](Token &Tok, bool &HasLexedNextToken) -> int {
         IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
                                            diag::err_feature_check_malformed);
-        return II ? hasAttribute(AttrSyntax::Declspec, nullptr, II,
-                                 getTargetInfo(), getLangOpts()) : 0;
+        if (II) {
+          const LangOptions &LangOpts = getLangOpts();
+          return LangOpts.DeclSpecKeyword &&
+                 hasAttribute(AttrSyntax::Declspec, nullptr, II,
+                              getTargetInfo(), LangOpts);
+        }
+
+        return false;
       });
   } else if (II == Ident__has_cpp_attribute ||
              II == Ident__has_c_attribute) {