On Sat, 6 Aug 2016, at 02:32 PM, Thomas Petazzoni wrote: > The current architecture detection, based on the "host_cpu" part of the > tuple does not work properly for a number of reason: > > - The code assumes that if host_cpu starts with "arm" then ARM > instructions are available, which is incorrect. Indeed, Cortex-M > platforms can run Linux, they are ARM platforms (so host_cpu = arm), > but they don't support ARM instructions: they support only the > Thumb-2 instruction set. > > - The armv7 case is also not very useful, as it is not standard at all > to pass armv7 as host_cpu even if the host system is actually ARMv7 > based. > > - For the same reason, the armv8 case is not very useful: ARMv8 is > AArch64, and there is already a separate case to handle this > architecture. > > So, this commit moves away from a host_cpu based logic, and instead > tests using AC_CHECK_DECLS() the built-in definitions of the compiler: > > - If we have __ARM_ARCH_ISA_ARM defined, then it's an ARM processor > that supports the ARM instruction set (this allows to exclude Thumb-2 > only processors). > > - If we have __ARM_ARCH_7A__, then we have an ARMv7-A processor, and > we can enable the corresponding optimizations > > - Same for __aarch64__, __i386__ and __x86_64__. > > In addition, we remove the AC_MSG_ERROR() that makes the build fail for > all architectures but the ones that are explicitly supported. Indeed, > webrtc-audio-processing builds just fine for other architectures (tested > on MIPS), it's just that none of the architecture-specific optimizations > will be used. > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com> > --- Looks good, will push shortly, thanks. -- Arun
