With 8e466dd09246 and 23ef50ae2d0c, we disable function pointer
sanitization in CI because the qemu code base does not support it.
We must disable this for normal usage of --enable-ubsan as well,
so move it there.

Append options rather than prepend, since all of this requires
proper ordering of options.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 .gitlab-ci.d/buildtest.yml | 10 ++++------
 meson.build                | 11 +++++++++--
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/.gitlab-ci.d/buildtest.yml b/.gitlab-ci.d/buildtest.yml
index aa32782405..fc5d516557 100644
--- a/.gitlab-ci.d/buildtest.yml
+++ b/.gitlab-ci.d/buildtest.yml
@@ -428,9 +428,8 @@ clang-system:
     job: amd64-fedora-container
   variables:
     IMAGE: fedora
-    CONFIGURE_ARGS: --cc=clang --cxx=clang++
-      --extra-cflags=-fsanitize=undefined --extra-cflags=-fno-sanitize-recover=undefined
-      --extra-cflags=-fno-sanitize=function
+    CONFIGURE_ARGS: --cc=clang --cxx=clang++ --enable-ubsan
+      --extra-cflags=-fno-sanitize-recover=undefined
     TARGETS: alpha-softmmu arm-softmmu m68k-softmmu mips64-softmmu s390x-softmmu
     MAKE_CHECK_ARGS: check-qtest check-tcg
 
@@ -441,10 +440,9 @@ clang-user:
   timeout: 70m
   variables:
     IMAGE: debian-all-test-cross
-    CONFIGURE_ARGS: --cc=clang --cxx=clang++ --disable-system
+    CONFIGURE_ARGS: --cc=clang --cxx=clang++ --disable-system --enable-ubsan
       --target-list-exclude=alpha-linux-user,microblazeel-linux-user,aarch64_be-linux-user,i386-linux-user,m68k-linux-user,mipsn32el-linux-user,xtensaeb-linux-user
-      --extra-cflags=-fsanitize=undefined --extra-cflags=-fno-sanitize-recover=undefined
-      --extra-cflags=-fno-sanitize=function
+      --extra-cflags=-fno-sanitize-recover=undefined
     MAKE_CHECK_ARGS: check-unit check-tcg
 
 # Set LD_JOBS=1 because this requires LTO and ld consumes a large amount of memory.
diff --git a/meson.build b/meson.build
index 19b18b4a8a..5b9ac6c6c5 100644
--- a/meson.build
+++ b/meson.build
@@ -488,8 +488,15 @@ if get_option('ubsan')
   # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84285
   if cc.links('int main(int argc, char **argv) { return argc + 1; }',
               args: [qemu_ldflags, '-fsanitize=undefined'])
-    qemu_cflags = ['-fsanitize=undefined'] + qemu_cflags
-    qemu_ldflags = ['-fsanitize=undefined'] + qemu_ldflags
+    qemu_cflags += ['-fsanitize=undefined']
+    qemu_ldflags += ['-fsanitize=undefined']
+
+    # Suppress undefined behaviour from function call to mismatched type.
+    # In addition, tcg prologue does not emit function type prefix
+    # required by function call sanitizer.
+    if cc.has_argument('-fno-sanitize=function')
+      qemu_cflags += ['-fno-sanitize=function']
+    endif
   else
     error('Your compiler does not support -fsanitize=undefined')
   endif
-- 
2.43.0