1 files changed, 85 insertions, 75 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 1290c615c00..dfa5647e9df 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9670,10 +9670,13 @@ static bool HasNonMultiVersionAttributes(const FunctionDecl *FD,
   return false;
 }
 
-static bool CheckMultiVersionAdditionalRules(Sema &S, const FunctionDecl *OldFD,
-                                             const FunctionDecl *NewFD,
-                                             bool CausesMV,
-                                             MultiVersionKind MVType) {
+bool Sema::areMultiversionVariantFunctionsCompatible(
+    const FunctionDecl *OldFD, const FunctionDecl *NewFD,
+    const PartialDiagnostic &NoProtoDiagID,
+    const PartialDiagnosticAt &NoteCausedDiagIDAt,
+    const PartialDiagnosticAt &NoSupportDiagIDAt,
+    const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
+    bool ConstexprSupported) {
   enum DoesntSupport {
     FuncTemplates = 0,
     VirtFuncs = 1,
@@ -9691,123 +9694,85 @@ static bool CheckMultiVersionAdditionalRules(Sema &S, const FunctionDecl *OldFD,
     ConstexprSpec = 2,
     InlineSpec = 3,
     StorageClass = 4,
-    Linkage = 5
+    Linkage = 5,
   };
 
-  bool IsCPUSpecificCPUDispatchMVType =
-      MVType == MultiVersionKind::CPUDispatch ||
-      MVType == MultiVersionKind::CPUSpecific;
-
   if (OldFD && !OldFD->getType()->getAs<FunctionProtoType>()) {
-    S.Diag(OldFD->getLocation(), diag::err_multiversion_noproto);
-    S.Diag(NewFD->getLocation(), diag::note_multiversioning_caused_here);
+    Diag(OldFD->getLocation(), NoProtoDiagID);
+    Diag(NoteCausedDiagIDAt.first, NoteCausedDiagIDAt.second);
     return true;
   }
 
   if (!NewFD->getType()->getAs<FunctionProtoType>())
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_noproto);
-
-  if (!S.getASTContext().getTargetInfo().supportsMultiVersioning()) {
-    S.Diag(NewFD->getLocation(), diag::err_multiversion_not_supported);
-    if (OldFD)
-      S.Diag(OldFD->getLocation(), diag::note_previous_declaration);
-    return true;
-  }
-
-  // For now, disallow all other attributes.  These should be opt-in, but
-  // an analysis of all of them is a future FIXME.
-  if (CausesMV && OldFD && HasNonMultiVersionAttributes(OldFD, MVType)) {
-    S.Diag(OldFD->getLocation(), diag::err_multiversion_no_other_attrs)
-        << IsCPUSpecificCPUDispatchMVType;
-    S.Diag(NewFD->getLocation(), diag::note_multiversioning_caused_here);
-    return true;
-  }
+    return Diag(NewFD->getLocation(), NoProtoDiagID);
 
-  if (HasNonMultiVersionAttributes(NewFD, MVType))
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_no_other_attrs)
-           << IsCPUSpecificCPUDispatchMVType;
-
-  if (NewFD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_doesnt_support)
-           << IsCPUSpecificCPUDispatchMVType << FuncTemplates;
+  if (!TemplatesSupported &&
+      NewFD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
+    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+           << FuncTemplates;
 
   if (const auto *NewCXXFD = dyn_cast<CXXMethodDecl>(NewFD)) {
     if (NewCXXFD->isVirtual())
-      return S.Diag(NewCXXFD->getLocation(),
-                    diag::err_multiversion_doesnt_support)
-             << IsCPUSpecificCPUDispatchMVType << VirtFuncs;
+      return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+             << VirtFuncs;
 
-    if (const auto *NewCXXCtor = dyn_cast<CXXConstructorDecl>(NewFD))
-      return S.Diag(NewCXXCtor->getLocation(),
-                    diag::err_multiversion_doesnt_support)
-             << IsCPUSpecificCPUDispatchMVType << Constructors;
+    if (isa<CXXConstructorDecl>(NewCXXFD))
+      return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+             << Constructors;
 
-    if (const auto *NewCXXDtor = dyn_cast<CXXDestructorDecl>(NewFD))
-      return S.Diag(NewCXXDtor->getLocation(),
-                    diag::err_multiversion_doesnt_support)
-             << IsCPUSpecificCPUDispatchMVType << Destructors;
+    if (isa<CXXDestructorDecl>(NewCXXFD))
+      return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+             << Destructors;
   }
 
   if (NewFD->isDeleted())
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_doesnt_support)
-           << IsCPUSpecificCPUDispatchMVType << DeletedFuncs;
+    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+           << DeletedFuncs;
 
   if (NewFD->isDefaulted())
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_doesnt_support)
-           << IsCPUSpecificCPUDispatchMVType << DefaultedFuncs;
+    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+           << DefaultedFuncs;
 
-  if (NewFD->isConstexpr() && (MVType == MultiVersionKind::CPUDispatch ||
-                               MVType == MultiVersionKind::CPUSpecific))
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_doesnt_support)
-           << IsCPUSpecificCPUDispatchMVType
+  if (!ConstexprSupported && NewFD->isConstexpr())
+    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
            << (NewFD->isConsteval() ? ConstevalFuncs : ConstexprFuncs);
 
-  QualType NewQType = S.getASTContext().getCanonicalType(NewFD->getType());
+  QualType NewQType = Context.getCanonicalType(NewFD->getType());
   const auto *NewType = cast<FunctionType>(NewQType);
   QualType NewReturnType = NewType->getReturnType();
 
   if (NewReturnType->isUndeducedType())
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_doesnt_support)
-           << IsCPUSpecificCPUDispatchMVType << DeducedReturn;
-
-  // Only allow transition to MultiVersion if it hasn't been used.
-  if (OldFD && CausesMV && OldFD->isUsed(false))
-    return S.Diag(NewFD->getLocation(), diag::err_multiversion_after_used);
+    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
+           << DeducedReturn;
 
   // Ensure the return type is identical.
   if (OldFD) {
-    QualType OldQType = S.getASTContext().getCanonicalType(OldFD->getType());
+    QualType OldQType = Context.getCanonicalType(OldFD->getType());
     const auto *OldType = cast<FunctionType>(OldQType);
     FunctionType::ExtInfo OldTypeInfo = OldType->getExtInfo();
     FunctionType::ExtInfo NewTypeInfo = NewType->getExtInfo();
 
     if (OldTypeInfo.getCC() != NewTypeInfo.getCC())
-      return S.Diag(NewFD->getLocation(), diag::err_multiversion_diff)
-             << CallingConv;
+      return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << CallingConv;
 
     QualType OldReturnType = OldType->getReturnType();
 
     if (OldReturnType != NewReturnType)
-      return S.Diag(NewFD->getLocation(), diag::err_multiversion_diff)
-             << ReturnType;
+      return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << ReturnType;
 
     if (OldFD->getConstexprKind() != NewFD->getConstexprKind())
-      return S.Diag(NewFD->getLocation(), diag::err_multiversion_diff)
-             << ConstexprSpec;
+      return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << ConstexprSpec;
 
     if (OldFD->isInlineSpecified() != NewFD->isInlineSpecified())
-      return S.Diag(NewFD->getLocation(), diag::err_multiversion_diff)
-             << InlineSpec;
+      return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << InlineSpec;
 
     if (OldFD->getStorageClass() != NewFD->getStorageClass())
-      return S.Diag(NewFD->getLocation(), diag::err_multiversion_diff)
-             << StorageClass;
+      return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << StorageClass;
 
     if (OldFD->isExternC() != NewFD->isExternC())
-      return S.Diag(NewFD->getLocation(), diag::err_multiversion_diff)
-             << Linkage;
+      return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << Linkage;
 
-    if (S.CheckEquivalentExceptionSpec(
+    if (CheckEquivalentExceptionSpec(
             OldFD->getType()->getAs<FunctionProtoType>(), OldFD->getLocation(),
             NewFD->getType()->getAs<FunctionProtoType>(), NewFD->getLocation()))
       return true;
@@ -9815,6 +9780,51 @@ static bool CheckMultiVersionAdditionalRules(Sema &S, const FunctionDecl *OldFD,
   return false;
 }
 
+static bool CheckMultiVersionAdditionalRules(Sema &S, const FunctionDecl *OldFD,
+                                             const FunctionDecl *NewFD,
+                                             bool CausesMV,
+                                             MultiVersionKind MVType) {
+  if (!S.getASTContext().getTargetInfo().supportsMultiVersioning()) {
+    S.Diag(NewFD->getLocation(), diag::err_multiversion_not_supported);
+    if (OldFD)
+      S.Diag(OldFD->getLocation(), diag::note_previous_declaration);
+    return true;
+  }
+
+  bool IsCPUSpecificCPUDispatchMVType =
+      MVType == MultiVersionKind::CPUDispatch ||
+      MVType == MultiVersionKind::CPUSpecific;
+
+  // For now, disallow all other attributes.  These should be opt-in, but
+  // an analysis of all of them is a future FIXME.
+  if (CausesMV && OldFD && HasNonMultiVersionAttributes(OldFD, MVType)) {
+    S.Diag(OldFD->getLocation(), diag::err_multiversion_no_other_attrs)
+        << IsCPUSpecificCPUDispatchMVType;
+    S.Diag(NewFD->getLocation(), diag::note_multiversioning_caused_here);
+    return true;
+  }
+
+  if (HasNonMultiVersionAttributes(NewFD, MVType))
+    return S.Diag(NewFD->getLocation(), diag::err_multiversion_no_other_attrs)
+           << IsCPUSpecificCPUDispatchMVType;
+
+  // Only allow transition to MultiVersion if it hasn't been used.
+  if (OldFD && CausesMV && OldFD->isUsed(false))
+    return S.Diag(NewFD->getLocation(), diag::err_multiversion_after_used);
+
+  return S.areMultiversionVariantFunctionsCompatible(
+      OldFD, NewFD, S.PDiag(diag::err_multiversion_noproto),
+      PartialDiagnosticAt(NewFD->getLocation(),
+                          S.PDiag(diag::note_multiversioning_caused_here)),
+      PartialDiagnosticAt(NewFD->getLocation(),
+                          S.PDiag(diag::err_multiversion_doesnt_support)
+                              << IsCPUSpecificCPUDispatchMVType),
+      PartialDiagnosticAt(NewFD->getLocation(),
+                          S.PDiag(diag::err_multiversion_diff)),
+      /*TemplatesSupported=*/false,
+      /*ConstexprSupported=*/!IsCPUSpecificCPUDispatchMVType);
+}
+
 /// Check the validity of a multiversion function declaration that is the
 /// first of its kind. Also sets the multiversion'ness' of the function itself.
 ///