[clang] 67f08bf - [Clang] [Sema] Ignore invalid multiversion function redeclarations

[Evgeny Shulgin via cfe-commits]

Author: Evgeny Shulgin
Date: 2022-09-13T20:12:09Z
New Revision: 67f08bf1bfa85fcdc1d91a3e6cce703e94611244

URL: https://github.com/llvm/llvm-project/commit/67f08bf1bfa85fcdc1d91a3e6cce703e94611244
DIFF: https://github.com/llvm/llvm-project/commit/67f08bf1bfa85fcdc1d91a3e6cce703e94611244.diff

LOG: [Clang] [Sema] Ignore invalid multiversion function redeclarations

If a redeclaration of a multiversion function is invalid,
it may be in a broken condition (for example, missing an important
attribute). We shouldn't analyze invalid redeclarations.

Fixes https://github.com/llvm/llvm-project/issues/57343

Reviewed By: tahonermann

Differential Revision: https://reviews.llvm.org/D133641

Added: 
    

Modified: 
    clang/lib/Sema/SemaDecl.cpp
    clang/test/Sema/attr-target-mv.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 58774c0fa44a3..e4bd827b38d39 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -11082,11 +11082,11 @@ static bool CheckMultiVersionAdditionalDecl(
   bool MayNeedOverloadableChecks =
       AllowOverloadingOfFunction(Previous, S.Context, NewFD);
 
-  // Next, check ALL non-overloads to see if this is a redeclaration of a
-  // previous member of the MultiVersion set.
+  // Next, check ALL non-invalid non-overloads to see if this is a redeclaration
+  // of a previous member of the MultiVersion set.
   for (NamedDecl *ND : Previous) {
     FunctionDecl *CurFD = ND->getAsFunction();
-    if (!CurFD)
+    if (!CurFD || CurFD->isInvalidDecl())
       continue;
     if (MayNeedOverloadableChecks &&
         S.IsOverload(NewFD, CurFD, UseMemberUsingDeclRules))

diff  --git a/clang/test/Sema/attr-target-mv.c b/clang/test/Sema/attr-target-mv.c
index b02b13079163b..8218771275e1b 100644
--- a/clang/test/Sema/attr-target-mv.c
+++ b/clang/test/Sema/attr-target-mv.c
@@ -52,6 +52,15 @@ int __attribute__((target("default"))) redef2(void) { return 1;}
 // expected-note at -2 {{previous definition is here}}
 int __attribute__((target("default"))) redef2(void) { return 1;}
 
+int redef3(void) { return 1; }
+// expected-warning at +4 {{attribute declaration must precede definition}}
+// expected-note at -2 {{previous definition is here}}
+// expected-error at +2 {{redefinition of 'redef3'}}
+// expected-note at -4 {{previous definition is here}}
+int __attribute__((target("default"))) redef3(void) { return 1; }
+// allow this, since we don't complain about more than one redefinition
+int __attribute__((target("sse4.2"))) redef3(void) { return 1; }
+
 int __attribute__((target("sse4.2"))) mv_after_use(void) { return 1; }
 int use3(void) {
   return mv_after_use();