From 3bf10012e0a8e327b94cc1af4bccf6cc32f95786 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Tue, 26 Jul 2022 11:00:11 +0300
Subject: [PATCH] MDEV-28762: Fixup for clang

Unlike GCC, clang could optimize away alloca() and thus the
ALLOCATE_MEM_ON_STACK() instrumentation. To make it harder, let us
invoke a non-inline function on the entire allocated buffer.
---
 sql/item_jsonfunc.cc | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sql/item_jsonfunc.cc b/sql/item_jsonfunc.cc
index 2fa6b19d95f..c0f063639bc 100644
--- a/sql/item_jsonfunc.cc
+++ b/sql/item_jsonfunc.cc
@@ -31,9 +31,8 @@
 #define ALLOCATE_MEM_ON_STACK(A) do \
                               { \
                                 uchar *array= (uchar*)alloca(A); \
-                                array[0]= 1; \
-                                array[0]++; \
-                                array[0] ? array[0]++ : array[0]--; \
+                                bzero(array, A); \
+                                my_checksum(0, array, A); \
                               } while(0)
 
 /*