1 files changed, 305 insertions, 0 deletions
diff --git a/build/moz.configure/arm.configure b/build/moz.configure/arm.configure
new file mode 100644
index 0000000000..5d26f4d732
--- /dev/null
+++ b/build/moz.configure/arm.configure
@@ -0,0 +1,305 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+@depends(target.os)
+def arm_option_defaults(os):
+    if os == "Android":
+        arch = "armv7-a"
+        thumb = "yes"
+        fpu = "neon"
+        float_abi = "softfp"
+    else:
+        arch = thumb = fpu = float_abi = "toolchain-default"
+    return namespace(
+        arch=arch,
+        thumb=thumb,
+        fpu=fpu,
+        float_abi=float_abi,
+    )
+
+
+# Note: '{...|}' in the help of all options with a non-constant default to
+# make the lint happy. The first arm is always going to be used, because a
+# default is always returned. The lint is fooled by this file being
+# conditional. If it weren't conditional, the lint wouldn't ask for '{|}' to
+# be there.
+option(
+    "--with-arch",
+    nargs=1,
+    default=arm_option_defaults.arch,
+    help="{Use specific CPU features (-march=type). Resets thumb, fpu, "
+    "float-abi, etc. defaults when set|}",
+)
+
+
+@depends("--with-arch")
+def arch_option(value):
+    if value:
+        if value[0] != "toolchain-default":
+            return ["-march={}".format(value[0])]
+    return []
+
+
+option(
+    "--with-thumb",
+    choices=("yes", "no", "toolchain-default"),
+    default=arm_option_defaults.thumb,
+    nargs="?",
+    help="{Use Thumb instruction set (-mthumb)|}",
+)
+
+
+def normalize_arm_option(value):
+    if value:
+        if len(value):
+            if value[0] == "yes":
+                return True
+            elif value[0] == "no":
+                return False
+            else:
+                return value[0]
+        return True
+    return False
+
+
+@depends("--with-thumb")
+def thumb_option(value):
+    value = normalize_arm_option(value)
+    if value is True:
+        return ["-mthumb"]
+    if value is False:
+        return ["-marm"]
+    return []
+
+
+option(
+    "--with-thumb-interwork",
+    choices=("yes", "no", "toolchain-default"),
+    default="toolchain-default",
+    nargs="?",
+    help="Use Thumb/ARM instuctions interwork (-mthumb-interwork)",
+)
+
+
+@depends("--with-thumb-interwork")
+def thumb_interwork_option(value):
+    value = normalize_arm_option(value)
+    if value is True:
+        return ["-mthumb-interwork"]
+    if value is False:
+        return ["-mno-thumb-interwork"]
+    return []
+
+
+option(
+    "--with-fpu",
+    nargs=1,
+    default=arm_option_defaults.fpu,
+    help="{Use specific FPU type (-mfpu=type)|}",
+)
+
+
+@depends("--with-fpu")
+def fpu_option(value):
+    if value:
+        if value[0] != "toolchain-default":
+            return ["-mfpu={}".format(value[0])]
+    return []
+
+
+option(
+    "--with-float-abi",
+    nargs=1,
+    default=arm_option_defaults.float_abi,
+    help="{Use specific arm float ABI (-mfloat-abi=type)|}",
+)
+
+
+@depends("--with-float-abi")
+def float_abi_option(value):
+    if value:
+        if value[0] != "toolchain-default":
+            return ["-mfloat-abi={}".format(value[0])]
+    return []
+
+
+option(
+    "--with-soft-float",
+    choices=("yes", "no", "toolchain-default"),
+    default="toolchain-default",
+    nargs="?",
+    help="Use soft float library (-msoft-float)",
+)
+
+
+@depends("--with-soft-float")
+def soft_float_option(value):
+    value = normalize_arm_option(value)
+    if value is True:
+        return ["-msoft-float"]
+    if value is False:
+        return ["-mno-soft-float"]
+    return []
+
+
+check_and_add_flag(
+    "-mno-unaligned-access", when=depends(target.os)(lambda os: os == "Android")
+)
+
+
+# The set of flags that clang understands
+@depends(
+    arch_option,
+    thumb_option,
+    fpu_option,
+    float_abi_option,
+    soft_float_option,
+)
+def all_clang_arm_flags(arch, thumb, fpu, float_abi, soft_float):
+    return arch + thumb + fpu + float_abi + soft_float
+
+
+# All the flags the compiler understands. When the compiler is clang, this
+# still includes unsupported flags, but we live it to configure to fail
+# during a compiler check. These checks aren't available for clang as used
+# by bindgen, so we keep the separate set of flags for clang for bindgen.
+@depends(all_clang_arm_flags, thumb_interwork_option)
+def all_arm_flags(flags, interwork):
+    return flags + interwork
+
+
+add_old_configure_assignment("_ARM_FLAGS", all_arm_flags)
+add_old_configure_assignment("_THUMB_FLAGS", thumb_option)
+
+
+@depends(configure_cache, c_compiler, all_arm_flags)
+@checking("ARM version support in compiler", lambda x: x.arm_arch)
+@imports(_from="textwrap", _import="dedent")
+def arm_target(configure_cache, compiler, all_arm_flags):
+    # We're going to preprocess the following source to figure out some details
+    # about the arm target options we have enabled.
+    source = dedent(
+        """\
+        %ARM_ARCH __ARM_ARCH
+        #if __thumb2__
+        %THUMB2 yes
+        #else
+        %THUMB2 no
+        #endif
+        // Confusingly, the __SOFTFP__ preprocessor variable indicates the
+        // "softfloat" ABI, not the "softfp" ABI.
+        #if __SOFTFP__
+        %FLOAT_ABI soft
+        #elif __ARM_PCS_VFP
+        %FLOAT_ABI hard
+        #else
+        %FLOAT_ABI softfp
+        #endif
+        // There is more subtlety to it than this preprocessor test, but MOZ_FPU doesn't
+        // need to be too fine-grained.
+        #if __ARM_NEON
+        %FPU neon
+        #elif __ARM_VFPV2__ || __ARM_FP == 12
+        %FPU vfpv2
+        #elif __ARM_VFPV3__
+        %FPU vfpv3
+        #elif __ARM_VFPV4__ || __ARM_FP == 14
+        %FPU vfpv4
+        #elif __ARM_FPV5__
+        %FPU fp-armv8
+        #endif
+    """
+    )
+    result = try_invoke_compiler(
+        configure_cache,
+        [compiler.compiler] + compiler.flags,
+        compiler.language,
+        source,
+        ["-E"] + all_arm_flags,
+        wrapper=compiler.wrapper,
+    )
+    # Metadata emitted by preprocessors such as GCC with LANG=ja_JP.utf-8 may
+    # have non-ASCII characters. Treat the output as bytearray.
+    data = {"fpu": None}  # fpu may not get a value from the preprocessor.
+    for line in result.splitlines():
+        if line.startswith("%"):
+            k, _, v = line.partition(" ")
+            k = k.lstrip("%").lower()
+            if k == "arm_arch":
+                data[k] = int(v)
+            else:
+                data[k] = {
+                    "yes": True,
+                    "no": False,
+                }.get(v, v)
+            log.debug("%s = %s", k, data[k])
+
+    return namespace(**data)
+
+
+@depends(arm_target.arm_arch, when=depends(target.os)(lambda os: os == "Android"))
+def armv7(arch):
+    if arch < 7:
+        die("Android/armv6 and earlier are not supported")
+
+
+set_config("MOZ_THUMB2", True, when=arm_target.thumb2)
+set_define("MOZ_THUMB2", True, when=arm_target.thumb2)
+
+
+have_arm_simd = c_compiler.try_compile(
+    body='asm("uqadd8 r1, r1, r2");', check_msg="for ARM SIMD support in compiler"
+)
+
+set_config("HAVE_ARM_SIMD", have_arm_simd)
+set_define("HAVE_ARM_SIMD", have_arm_simd)
+
+have_arm_neon = c_compiler.try_compile(
+    body='asm(".fpu neon\\n vadd.i8 d0, d0, d0");',
+    check_msg="for ARM NEON support in compiler",
+)
+
+set_config("HAVE_ARM_NEON", have_arm_neon)
+set_define("HAVE_ARM_NEON", have_arm_neon)
+
+
+# We don't need to build NEON support if we're targetting a non-NEON device.
+# This matches media/webrtc/trunk/webrtc/build/common.gypi.
+@depends(arm_target.arm_arch, when=have_arm_neon)
+def build_arm_neon(arm_arch):
+    return arm_arch >= 7
+
+
+set_config("BUILD_ARM_NEON", True, when=build_arm_neon)
+set_define("BUILD_ARM_NEON", True, when=build_arm_neon)
+
+
+set_config("ARM_ARCH", depends(arm_target.arm_arch)(lambda x: str(x)))
+set_config("MOZ_FPU", arm_target.fpu)
+
+
+@depends(arm_target)
+def neon_flags(arm_target):
+    # Building with -mfpu=neon requires either the "softfp" or the
+    # "hardfp" ABI. Depending on the compiler's default target, and the
+    # CFLAGS, the default ABI might be neither, in which case it is the
+    # "softfloat" ABI.
+    # The "softfloat" ABI is binary-compatible with the "softfp" ABI, so
+    # we can safely mix code built with both ABIs. So, if we detect
+    # that compiling uses the "softfloat" ABI, force the use of the
+    # "softfp" ABI instead.
+    flags = ["-mfpu=neon"]
+    if arm_target.float_abi == "soft":
+        flags.append("-mfloat-abi=softfp")
+    if arm_target.arm_arch < 7:
+        # clang needs to be forced to at least armv7 for -mfpu=neon to do
+        # something.
+        flags.append("-march=armv7-a")
+    return tuple(flags)
+
+
+set_config("NEON_FLAGS", neon_flags)