[clang] Fix or emit diagnostic for checked arithmetic builtins with

_ExtInt types

- Fix computed size for _ExtInt types passed to checked arithmetic
  builtins.
- Emit diagnostic when signed _ExtInt larger than 128-bits is passed
    to __builtin_mul_overflow.
- Change Sema checks for builtins to accept placeholder types.

Differential Revision: https://reviews.llvm.org/D81420

1 files changed, 31 insertions, 19 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 85126e0..22f25f9 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -283,48 +283,60 @@ static bool SemaBuiltinAlignment(Sema &S, CallExpr *TheCall, unsigned ID) {
   return false;
 }
 
-static bool SemaBuiltinOverflow(Sema &S, CallExpr *TheCall) {
+static bool SemaBuiltinOverflow(Sema &S, CallExpr *TheCall,
+                                unsigned BuiltinID) {
   if (checkArgCount(S, TheCall, 3))
     return true;
 
   // First two arguments should be integers.
   for (unsigned I = 0; I < 2; ++I) {
-    ExprResult Arg = TheCall->getArg(I);
+    ExprResult Arg = S.DefaultFunctionArrayLvalueConversion(TheCall->getArg(I));
+    if (Arg.isInvalid()) return true;
+    TheCall->setArg(I, Arg.get());
+
     QualType Ty = Arg.get()->getType();
     if (!Ty->isIntegerType()) {
       S.Diag(Arg.get()->getBeginLoc(), diag::err_overflow_builtin_must_be_int)
           << Ty << Arg.get()->getSourceRange();
       return true;
     }
-    InitializedEntity Entity = InitializedEntity::InitializeParameter(
-        S.getASTContext(), Ty, /*consume*/ false);
-    Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
-    if (Arg.isInvalid())
-      return true;
-    TheCall->setArg(I, Arg.get());
   }
 
   // Third argument should be a pointer to a non-const integer.
   // IRGen correctly handles volatile, restrict, and address spaces, and
   // the other qualifiers aren't possible.
   {
-    ExprResult Arg = TheCall->getArg(2);
+    ExprResult Arg = S.DefaultFunctionArrayLvalueConversion(TheCall->getArg(2));
+    if (Arg.isInvalid()) return true;
+    TheCall->setArg(2, Arg.get());
+
     QualType Ty = Arg.get()->getType();
     const auto *PtrTy = Ty->getAs<PointerType>();
-    if (!(PtrTy && PtrTy->getPointeeType()->isIntegerType() &&
-          !PtrTy->getPointeeType().isConstQualified())) {
+    if (!PtrTy ||
+        !PtrTy->getPointeeType()->isIntegerType() ||
+        PtrTy->getPointeeType().isConstQualified()) {
       S.Diag(Arg.get()->getBeginLoc(),
              diag::err_overflow_builtin_must_be_ptr_int)
-          << Ty << Arg.get()->getSourceRange();
+        << Ty << Arg.get()->getSourceRange();
       return true;
     }
-    InitializedEntity Entity = InitializedEntity::InitializeParameter(
-        S.getASTContext(), Ty, /*consume*/ false);
-    Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
-    if (Arg.isInvalid())
-      return true;
-    TheCall->setArg(2, Arg.get());
   }
+
+  // Disallow signed ExtIntType args larger than 128 bits to mul function until
+  // we improve backend support.
+  if (BuiltinID == Builtin::BI__builtin_mul_overflow) {
+    for (unsigned I = 0; I < 3; ++I) {
+      const auto Arg = TheCall->getArg(I);
+      // Third argument will be a pointer.
+      auto Ty = I < 2 ? Arg->getType() : Arg->getType()->getPointeeType();
+      if (Ty->isExtIntType() && Ty->isSignedIntegerType() &&
+          S.getASTContext().getIntWidth(Ty) > 128)
+        return S.Diag(Arg->getBeginLoc(),
+                      diag::err_overflow_builtin_ext_int_max_size)
+               << 128;
+    }
+  }
+
   return false;
 }
 
@@ -1728,7 +1740,7 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
   case Builtin::BI__builtin_add_overflow:
   case Builtin::BI__builtin_sub_overflow:
   case Builtin::BI__builtin_mul_overflow:
-    if (SemaBuiltinOverflow(*this, TheCall))
+    if (SemaBuiltinOverflow(*this, TheCall, BuiltinID))
       return ExprError();
     break;
   case Builtin::BI__builtin_operator_new: