[xen staging] kconfig/randconfig: enable UBSAN for randconfig

[patchbot@xxxxxxx]

commit 6a804ff8b469a6f992e95eab720c99fe00622ab0
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Wed Mar 12 18:51:43 2025 +0100
Commit:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
CommitDate: Thu Mar 20 17:16:18 2025 +0100

    kconfig/randconfig: enable UBSAN for randconfig
    
    Introduce an additional Kconfig check to only offer the option if the
    compiler supports -fsanitize=undefined.
    
    We no longer use Travis CI, so the original motivation for not enabling
    UBSAN might no longer present.  Regardless, the option won't be present in
    the first place if the compiler doesn't support -fsanitize=undefined.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/Kconfig                        | 4 ++++
 xen/Kconfig.debug                  | 2 +-
 xen/tools/kconfig/allrandom.config | 1 -
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/Kconfig b/xen/Kconfig
index 72fdb83760..2128f0ccfc 100644
--- a/xen/Kconfig
+++ b/xen/Kconfig
@@ -37,6 +37,10 @@ config CC_HAS_VISIBILITY_ATTRIBUTE
 config CC_SPLIT_SECTIONS
        bool
 
+# Compiler supports -fsanitize=undefined
+config CC_HAS_UBSAN
+       def_bool $(cc-option,-fsanitize=undefined)
+
 # Set code alignment.
 #
 # Allow setting on a boolean basis, and then convert such selection to an
diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug
index c4a8d86912..f7cc5ffaab 100644
--- a/xen/Kconfig.debug
+++ b/xen/Kconfig.debug
@@ -98,7 +98,7 @@ config SCRUB_DEBUG
 
 config UBSAN
        bool "Undefined behaviour sanitizer"
-       depends on HAS_UBSAN
+       depends on HAS_UBSAN && CC_HAS_UBSAN
        help
          Enable undefined behaviour sanitizer. It uses compiler to insert code
          snippets so that undefined behaviours in C are detected during 
runtime.
diff --git a/xen/tools/kconfig/allrandom.config 
b/xen/tools/kconfig/allrandom.config
index 76f74320b5..c7753ac4ad 100644
--- a/xen/tools/kconfig/allrandom.config
+++ b/xen/tools/kconfig/allrandom.config
@@ -1,4 +1,3 @@
 # Explicit option choices not subject to regular RANDCONFIG
 
 CONFIG_GCOV_FORMAT_AUTODETECT=y
-CONFIG_UBSAN=n
--
generated by git-patchbot for /home/xen/git/xen.git#staging