tree 16a5602ed742d7ceabcc0a04a4ba45cabb25e551
parent a74b0d0a6dcca4e7d7561655256a8cf671d80ac1
author Akihiko Odaki <akihiko.odaki@daynix.com> 1680678030 +0900
committer Paolo Bonzini <pbonzini@redhat.com> 1681982255 +0200

configure: Avoid -Werror=maybe-uninitialized

The configure script used to compile some code which dereferences memory
with ubsan to verify the compiler can link with ubsan library which
detects dereferencing of uninitialized memory. However, as the
dereferenced memory was allocated in the same code, GCC can statically
detect the unitialized memory dereference and emit maybe-uninitialized
warning. If -Werror is set, this becomes an error, and the configure
script incorrectly thinks the error indicates the compiler cannot use
ubsan.

Fix this error by replacing the code with another function which adds
1 to a signed integer argument. This brings in ubsan to detect if it
causes signed integer overflow. As the value of the argument cannot be
statically determined, the new function is also immune to compiler
warnings.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230405070030.23148-1-akihiko.odaki@daynix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>