r351212 - Fix cpu-dispatch MV regression caused by r347812

[Erich Keane via cfe-commits]

Author: erichkeane
Date: Tue Jan 15 09:51:09 2019
New Revision: 351212

URL: http://llvm.org/viewvc/llvm-project?rev=351212&view=rev
Log:
Fix cpu-dispatch MV regression caused by r347812

r347812 permitted forward declarations for cpu-dispatch functions, which
are occassionally useful as exposition in  header files.  However, this inadvertently
permitted this function to become multiversioned after a usage.  This
patch ensures that the "CausesMV" checks are still run in the
forward-declaration case.

Change-Id: Icb6f975a2d068f088b89e3bbe26cf1d24f5a972c

Modified:
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/Sema/attr-cpuspecific.c

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=351212&r1=351211&r2=351212&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Tue Jan 15 09:51:09 2019
@@ -9816,7 +9816,8 @@ static bool CheckMultiVersionAdditionalD
     return true;
   }
 
-  if (CheckMultiVersionAdditionalRules(S, OldFD, NewFD, false, NewMVType)) {
+  if (CheckMultiVersionAdditionalRules(S, OldFD, NewFD,
+                                       !OldFD->isMultiVersion(), NewMVType)) {
     NewFD->setInvalidDecl();
     return true;
   }

Modified: cfe/trunk/test/Sema/attr-cpuspecific.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/attr-cpuspecific.c?rev=351212&r1=351211&r2=351212&view=diff
==============================================================================
--- cfe/trunk/test/Sema/attr-cpuspecific.c (original)
+++ cfe/trunk/test/Sema/attr-cpuspecific.c Tue Jan 15 09:51:09 2019
@@ -40,6 +40,14 @@ int __attribute__((cpu_dispatch(atom)))
 int allow_fwd_decl(void);
 int __attribute__((cpu_dispatch(atom))) allow_fwd_decl(void) {}
 
+int allow_fwd_decl2(void);
+void use_fwd_decl(void) {
+  allow_fwd_decl2();
+}
+// expected-error at +1 {{function declaration cannot become a multiversioned function after first usage}}
+int __attribute__((cpu_dispatch(atom))) allow_fwd_decl2(void) {}
+
+
 int __attribute__((cpu_specific(atom))) redecl4(void);
 // expected-error at +1 {{function declaration is missing 'cpu_specific' or 'cpu_dispatch' attribute in a multiversioned function}}
 int redecl4(void);