Don't claim that va_start has special semantic checks

We don't have special checks for BI_va_start in
Sema::CheckBuiltinFunctionCall, so setting the 't' flag for va_start in
Builtins.def disables semantic checking for it. That's not desired, and
IRGen crashes when it tries to generate a call to va_start that doesn't
have at least one argument.

Follow-up to r322573

Fixes PR36565

llvm-svn: 326622

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/test/Sema/varargs.c b/clang/test/Sema/varargs.c
index 0ade0cf0aaf..3fa429163ff 100644
--- a/clang/test/Sema/varargs.c
+++ b/clang/test/Sema/varargs.c
@@ -112,3 +112,12 @@ void f13(enum E1 e, ...) {
 #endif
   __builtin_va_end(va);
 }
+
+void f14(int e, ...) {
+  // expected-warning@+3 {{implicitly declaring library function 'va_start'}}
+  // expected-note@+2 {{include the header <stdarg.h>}}
+  // expected-error@+1 {{too few arguments to function call}}
+  va_start();
+  __builtin_va_list va;
+  va_start(va, e);
+}