Fix <rdar://problem/6786597> varargs not supported for Blocks under clang.

Teach Sema::SemaBuiltinVAStart() about blocks.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69201 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/variadic-block.c b/test/Sema/variadic-block.c
new file mode 100644
index 0000000..29f597b
--- /dev/null
+++ b/test/Sema/variadic-block.c
@@ -0,0 +1,41 @@
+// RUN: clang-cc %s -verify -fsyntax-only -fblocks
+
+#include <stdarg.h>
+
+int main(int argc, char *argv[]) {
+    
+    long (^addthem)(const char *, ...) = ^long (const char *format, ...){
+        va_list argp;
+        const char *p;
+        int i;
+        char c;
+        double d;
+        long result = 0;
+        va_start(argp, format);
+        for (p = format; *p; p++) switch (*p) {
+            case 'i':
+                i = va_arg(argp, int);
+                result += i;
+                break;
+            case 'd':
+                d = va_arg(argp, double);
+                result += (int)d;
+                break;
+            case 'c':
+                c = va_arg(argp, int);
+                result += c;
+                break;
+        }
+        return result;
+    };
+    long testresult = addthem("ii", 10, 20);
+    if (testresult != 30) {
+        return 1;
+    }
+    testresult = addthem("idc", 30, 40.0, 'a');
+    if (testresult != (70+'a')) {
+        return 1;
+    }
+    return 0;
+}
+