Typical slowdown introduced by AddressSanitizer is 2x.
UBSan shouldn't have much impact on runtime cost.
Enable it by default when --enable-debug, unless --disable-sanitizers.
Backports commit 247724cb302af5d70c8853154b640dfabf2bbb56 from qemu
GCC 4.9 and newer stopped warning for missing braces around the
"universal" C zero initializer {0}. One such initializer sneaked
into scsi/qemu-pr-helper.c and is breaking the build with such
older GCC versions.
Detect the lack of support for the idiom, and disable the warning
in that case.
Backports commit 20bc94a2b8449b7700b6bfa25a87ce2320a1c649 from qemu
Nobody has mentioned AIX host support on the mailing list for years,
and we have no test systems for it so it is most likely broken.
We've advertised in configure for two releases now that we plan
to drop support for this host OS, and have had no complaints.
Drop the AIX host support code.
We can also drop the now-unused AIX version of sys_cache_info().
Note that the _CALL_AIX define used in the PPC tcg backend is
also used for Linux PPC64, and so that code should not be removed.
Backports commit 7872375219c03682bda3f6191fa5f6a58238ed36 from qemu
This warning is included in -Wall by clang, but not by GCC (which only
enables it for -Wextra). Include it in the list of warnings we enable
to minimize the differences between the compilers:
Backports commit b98fcfd8840f290c406c32301340e96f00238a93 from qemu
This lets you build without TCG (hardware accelerationor qtest only). When
this flag is passed to configure, it will automatically filter out the target
list to only those that support KVM or Xen or HAX.
Backports commit b3f6ea7e55e8228d6f84d5cee7cb11cae917ba95 from qemu
The Cygwin target is really compiling for native Win32 with -mno-cygwin.
Except, GCC 4.7.0 has finally removed the long deprecated -mno-cygwin
option, and that happened about five years ago.
Let it rest in peace.
Backports commit c8645752ce31cc044ecc5f969a986fdcb6aab590 from qemu
This enables the multi-threaded system emulation by default for ARMv7
and ARMv8 guests using the x86_64 TCG backend. This is because on the
guest side:
- The ARM translate.c/translate-64.c have been converted to
- use MTTCG safe atomic primitives
- emit the appropriate barrier ops
- The ARM machine has been updated to
- hold the BQL when modifying shared cross-vCPU state
- defer powerctl changes to async safe work
All the host backends support the barrier and atomic primitives but
need to provide same-or-better support for normal load/store
operations.
Backports commit ca759f9e387db87e1719911f019bc60c74be9ed8 from qemu
Allow qemu to build on 32-bit hosts without 64-bit atomic ops.
Even if we only allow 32-bit hosts to multi-thread emulate 32-bit
guests, we still need some way to handle the 32-bit guest using a
64-bit atomic operation. Do so by dropping back to single-step.
Backports commit df79b996a7b21c6ea7847f7927a2e1a294b86c72 from qemu
Force the use of cmpxchg16b on x86_64.
Wikipedia suggests that only very old AMD64 (circa 2004) did not have
this instruction. Further, it's required by Windows 8 so no new cpus
will ever omit it.
If we truely care about these, then we could check this at startup time
and then avoid executing paths that use it.
Backports commit 7ebee43ee3e2fcd7b5063058b7ef74bc43216733 from qemu
QEMU's code relies on left shifts of signed integers always
being defined behaviour with the obvious 2s-complement
semantics. The only way to tell the compiler (and any
associated undefined-behaviour sanitizer) that we require a
C dialect with these semantics is to use the -fwrapv option.
This is a bit of a heavy hammer for the job as it also gives
us guaranteed semantics on integer arithmetic overflow which
in theory we don't require.
In an ideal world this would allow us to drop the warning
flag -Wno-shift-negative-value, but we must retain this to
avoid spurious warnings on clang versions predating the
fix to https://llvm.org/bugs/show_bug.cgi?id=25552.
Backports commit 2d31515bc0880a1cea86ce638d2a109f4f4e6f7d from qemu
MinGW seems to compile currently without warnings, so it should
be safe to enable -Werror now for this environment, too.
Backports commit e4650c81b3d15ba67236815defbb475c4bdf8690 from qemu
This fixes these warnings from shellcheck:
^-- SC2006: Use $(..) instead of deprecated `..`
Backports commit 89138857619b2a023c32200e9af780792ccaa8c3 from qemu
