[Sema] Don't allow applying address-of operator to a call to a function

with __unknown_anytype return type.

When the following code is compiled, Sema infers that the type of
__unknown_anytype is double:

extern __unknown_anytype func();
double *d = (double*)&func();

This triggers an assert in CodeGenFunction::EmitCallExprLValue because
it doesn't expect to see a call to a function with a non-reference
scalar return type.

This commit prevents the assert by making VisitUnaryAddrOf error out if
the address-of operator is applied to a call to a function with
__unknown_anytype return type.

rdar://problem/20287610

Differential revision: https://reviews.llvm.org/D26808

llvm-svn: 287410

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index fae8bf0f548..9d0d55e6876 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -14774,6 +14774,13 @@ namespace {
           << E->getSourceRange();
         return ExprError();
       }
+
+      if (isa<CallExpr>(E->getSubExpr())) {
+        S.Diag(E->getOperatorLoc(), diag::err_unknown_any_addrof_call)
+          << E->getSourceRange();
+        return ExprError();
+      }
+
       assert(E->getValueKind() == VK_RValue);
       assert(E->getObjectKind() == OK_Ordinary);
       E->setType(DestType);