r350398 - Prevent unreachable when checking invalid multiversion decls.

[Erich Keane via cfe-commits]

Author: erichkeane
Date: Fri Jan  4 07:24:06 2019
New Revision: 350398

URL: http://llvm.org/viewvc/llvm-project?rev=350398&view=rev
Log:
Prevent unreachable when checking invalid multiversion decls.

CPUSpecifc/CPUDispatch call resolution assumed that all declarations
that would be passed are valid, however this was an invalid assumption.
This patch deals with those situations by making the valid version take
priority.  Note that the checked ordering is arbitrary, since both are
replaced by calls to the resolver later.

Change-Id: I7ff2ec88c55a721d51bc1f39ea1a1fe242b4e45f

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

Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=350398&r1=350397&r2=350398&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
+++ cfe/trunk/lib/Sema/SemaOverload.cpp Fri Jan  4 07:24:06 2019
@@ -9023,6 +9023,11 @@ static bool isBetterMultiversionCandidat
       !Cand2.Function->isMultiVersion())
     return false;
 
+  // If Cand1 is invalid, it cannot be a better match, if Cand2 is invalid, this
+  // is obviously better.
+  if (Cand1.Function->isInvalidDecl()) return false;
+  if (Cand2.Function->isInvalidDecl()) return true;
+
   // If this is a cpu_dispatch/cpu_specific multiversion situation, prefer
   // cpu_dispatch, else arbitrarily based on the identifiers.
   bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>();

Modified: cfe/trunk/test/Sema/attr-cpuspecific.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/attr-cpuspecific.c?rev=350398&r1=350397&r2=350398&view=diff
==============================================================================
--- cfe/trunk/test/Sema/attr-cpuspecific.c (original)
+++ cfe/trunk/test/Sema/attr-cpuspecific.c Fri Jan  4 07:24:06 2019
@@ -92,3 +92,15 @@ __vectorcall int __attribute__((cpu_spec
 int __attribute__((cpu_dispatch(atom))) disp_with_body(void) {
   return 5;
 }
+
+// expected-error at +1 {{invalid option 'INVALID'}}
+int __attribute__((cpu_specific(INVALID))) called_invalid_value(void){ return 1;}
+// expected-warning at +3 {{attribute declaration must precede definition}}
+// expected-note at -2 2 {{previous definition is here}}
+// expected-error at +1 {{redefinition of}}
+int __attribute__((cpu_specific(pentium_iii))) called_invalid_value(void){ return 2;}
+int __attribute__((cpu_specific(pentium_4))) called_invalid_value(void){ return 3;}
+
+int use3(void) {
+  return called_invalid_value();
+}