[clang][bytecode][NFC] Diagnose no-constexpr memcpy/strlen versions (#118429)

Author: tbaederr

clang/lib/AST/ByteCode/InterpBuiltin.cpp

@@ -222,11 +222,25 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
   return true;
 }
 
+static void diagnoseNonConstexprBuiltin(InterpState &S, CodePtr OpPC,
+                                        unsigned ID) {
+  auto Loc = S.Current->getSource(OpPC);
+  if (S.getLangOpts().CPlusPlus11)
+    S.CCEDiag(Loc, diag::note_constexpr_invalid_function)
+        << /*isConstexpr=*/0 << /*isConstructor=*/0
+        << ("'" + S.getASTContext().BuiltinInfo.getName(ID) + "'").str();
+  else
+    S.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
+}
 static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
                                    const InterpFrame *Frame,
-                                   const CallExpr *Call) {
+                                   const Function *Func, const CallExpr *Call) {
+  unsigned ID = Func->getBuiltinID();
   const Pointer &StrPtr = getParam<Pointer>(Frame, 0);
 
+  if (ID == Builtin::BIstrlen)
+    diagnoseNonConstexprBuiltin(S, OpPC, ID);
+
   if (!CheckArray(S, OpPC, StrPtr))
     return false;
 
@@ -1781,12 +1795,16 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
                                    const InterpFrame *Frame,
                                    const Function *Func, const CallExpr *Call) {
   assert(Call->getNumArgs() == 3);
+  unsigned ID = Func->getBuiltinID();
   Pointer DestPtr = getParam<Pointer>(Frame, 0);
   const Pointer &SrcPtr = getParam<Pointer>(Frame, 1);
   const APSInt &Size =
       peekToAPSInt(S.Stk, *S.getContext().classify(Call->getArg(2)));
   assert(!Size.isSigned() && "memcpy and friends take an unsigned size");
 
+  if (ID == Builtin::BImemcpy)
+    diagnoseNonConstexprBuiltin(S, OpPC, ID);
+
   if (DestPtr.isDummy() || SrcPtr.isDummy())
     return false;
 
@@ -1830,7 +1848,8 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
       return false;
     break;
   case Builtin::BI__builtin_strlen:
-    if (!interp__builtin_strlen(S, OpPC, Frame, Call))
+  case Builtin::BIstrlen:
+    if (!interp__builtin_strlen(S, OpPC, Frame, F, Call))
       return false;
     break;
   case Builtin::BI__builtin_nan:
@@ -2271,6 +2290,7 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
     break;
 
   case Builtin::BI__builtin_memcpy:
+  case Builtin::BImemcpy:
     if (!interp__builtin_memcpy(S, OpPC, Frame, F, Call))
       return false;
     break;