package/webrtc-audio-processing/0001-configure.ac-fix-architecture-detection.patch

   1 From 233413841882608c6d5b98b6ce89fcb8a292db82 Mon Sep 17 00:00:00 2001
   2 From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   3 Date: Sat, 6 Aug 2016 10:22:34 +0200
   4 Subject: [PATCH] configure.ac: fix architecture detection
   5
   6 The current architecture detection, based on the "host_cpu" part of the
   7 tuple does not work properly for a number of reason:
   8
   9  - The code assumes that if host_cpu starts with "arm" then ARM
  10    instructions are available, which is incorrect. Indeed, Cortex-M
  11    platforms can run Linux, they are ARM platforms (so host_cpu = arm),
  12    but they don't support ARM instructions: they support only the
  13    Thumb-2 instruction set.
  14
  15  - The armv7 case is also not very useful, as it is not standard at all
  16    to pass armv7 as host_cpu even if the host system is actually ARMv7
  17    based.
  18
  19  - For the same reason, the armv8 case is not very useful: armv8 is
  20    never used as the host_cpu part of a tuple.
  21
  22 So, this commit moves away from a host_cpu based logic, and instead
  23 tests using AC_CHECK_DECLS() the built-in definitions of the compiler:
  24
  25  - If we have __ARM_ARCH_ISA_ARM defined, then it's an ARM processor
  26    that supports the ARM instruction set (this allows to exclude Thumb-2
  27    only processors).
  28
  29  - If we have __ARM_ARCH_7A__, then we have an ARMv7-A processor, and
  30    we can enable the corresponding optimizations
  31
  32  - Same for __i386__ and __x86_64__.
  33
  34 Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  35 ---
  36 Submitted upstream, under a slightly different form so that it applies
  37 on master:
  38
  39   https://lists.freedesktop.org/archives/pulseaudio-discuss/2016-August/026600.html
  40 ---
  41  configure.ac | 27 +++++++++------------------
  42  1 file changed, 9 insertions(+), 18 deletions(-)
  43
  44 diff --git a/configure.ac b/configure.ac
  45 index 6f9553b..836c6ad 100644
  46 --- a/configure.ac
  47 +++ b/configure.ac
  48 @@ -55,24 +55,15 @@ AS_CASE(["${host}"],
  49  )
  50  AC_SUBST(PLATFORM_CFLAGS)
  51
  52 -AS_CASE(["${host_cpu}"],
  53 -    [i?86|x86_64],
  54 -        [
  55 -         HAVE_X86=1
  56 -        ],
  57 -    [armv7*|armv8*],
  58 -        [
  59 -         HAVE_ARM=1
  60 -         HAVE_ARMV7=1
  61 -         ARCH_CFLAGS="-DWEBRTC_ARCH_ARM -DWEBRTC_ARCH_ARM_V7"
  62 -        ],
  63 -    [arm*],
  64 -        [
  65 -         HAVE_ARM=1
  66 -         ARCH_CFLAGS="-DWEBRTC_ARCH_ARM"
  67 -        ]
  68 -    # FIXME: Add MIPS support, see webrtc/BUILD.gn for defines
  69 -)
  70 +# Testing __ARM_ARCH_ISA_ARM since the code contains ARM instructions,
  71 +# which don't work on Thumb-2 only platforms (ARMv7-M).
  72 +AC_CHECK_DECLS([__ARM_ARCH_ISA_ARM],
  73 +       [HAVE_ARM=1; ARCH_CFLAGS="${ARCH_CFLAGS} -DWEBRTC_ARCH_ARM"])
  74 +AC_CHECK_DECLS([__ARM_ARCH_7A__],
  75 +       [HAVE_ARMV7=1; ARCH_CFLAGS="${ARCH_CFLAGS} -DWEBRTC_ARCH_ARM_V7"])
  76 +AC_CHECK_DECLS([__i386__], [HAVE_X86=1])
  77 +AC_CHECK_DECLS([__x86_64__], [HAVE_X86=1])
  78 +
  79  AM_CONDITIONAL(HAVE_X86, [test "x${HAVE_X86}" = "x1"])
  80  AM_CONDITIONAL(HAVE_ARM, [test "x${HAVE_ARM}" = "x1"])
  81  AM_CONDITIONAL(HAVE_ARMV7, [test "x${HAVE_ARMV7}" = "x1"])
  82 --
  83 2.7.4
  84