From 233413841882608c6d5b98b6ce89fcb8a292db82 Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Sat, 6 Aug 2016 10:22:34 +0200 Subject: [PATCH] configure.ac: fix architecture detection 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 never used as the host_cpu part of a tuple. 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 __i386__ and __x86_64__. Signed-off-by: Thomas Petazzoni --- Submitted upstream, under a slightly different form so that it applies on master: https://lists.freedesktop.org/archives/pulseaudio-discuss/2016-August/026600.html --- configure.ac | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/configure.ac b/configure.ac index 6f9553b..836c6ad 100644 --- a/configure.ac +++ b/configure.ac @@ -55,24 +55,15 @@ AS_CASE(["${host}"], ) AC_SUBST(PLATFORM_CFLAGS) -AS_CASE(["${host_cpu}"], - [i?86|x86_64], - [ - HAVE_X86=1 - ], - [armv7*|armv8*], - [ - HAVE_ARM=1 - HAVE_ARMV7=1 - ARCH_CFLAGS="-DWEBRTC_ARCH_ARM -DWEBRTC_ARCH_ARM_V7" - ], - [arm*], - [ - HAVE_ARM=1 - ARCH_CFLAGS="-DWEBRTC_ARCH_ARM" - ] - # FIXME: Add MIPS support, see webrtc/BUILD.gn for defines -) +# Testing __ARM_ARCH_ISA_ARM since the code contains ARM instructions, +# which don't work on Thumb-2 only platforms (ARMv7-M). +AC_CHECK_DECLS([__ARM_ARCH_ISA_ARM], + [HAVE_ARM=1; ARCH_CFLAGS="${ARCH_CFLAGS} -DWEBRTC_ARCH_ARM"]) +AC_CHECK_DECLS([__ARM_ARCH_7A__], + [HAVE_ARMV7=1; ARCH_CFLAGS="${ARCH_CFLAGS} -DWEBRTC_ARCH_ARM_V7"]) +AC_CHECK_DECLS([__i386__], [HAVE_X86=1]) +AC_CHECK_DECLS([__x86_64__], [HAVE_X86=1]) + AM_CONDITIONAL(HAVE_X86, [test "x${HAVE_X86}" = "x1"]) AM_CONDITIONAL(HAVE_ARM, [test "x${HAVE_ARM}" = "x1"]) AM_CONDITIONAL(HAVE_ARMV7, [test "x${HAVE_ARMV7}" = "x1"]) -- 2.7.4