# GN host architecture helpers.
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#
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# BUILD_ARCH's value corresponds to what uname returns as the machine name.
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# The mapping in gn_host_arch_name() tries to match several possible values
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# returned by the Linux kernel in uname(2) into the corresponding values GN
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# understands.
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def gn_host_arch_name(d):
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"""Returns a GN architecture name corresponding to the build host's machine
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architecture."""
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import re
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arch_translations = {
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r'aarch64.*': 'arm64',
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r'arm.*': 'arm',
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r'i[3456]86$': 'x86',
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r'x86_64$': 'x64',
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}
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build_arch = d.getVar("BUILD_ARCH")
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for arch_regexp, gn_arch_name in arch_translations.items():
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if re.match(arch_regexp, build_arch):
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return gn_arch_name
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bb.fatal('Unsuported BUILD_ARCH value: "%s"' % build_arch)
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# GN target architecture helpers.
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#
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# Determining the target architecture is more difficult, as there are many
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# different values we can use on the Yocto side (e.g. TUNE_ARCH, TARGET_ARCH,
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# MACHINEOVERRIDES etc). What we do is define the mapping with regular,
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# non-Python variables with overrides that are generic enough (i.e. "x86"
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# instead of "i586") and then use gn_target_arch_name() to return the right
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# value with some validation.
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GN_TARGET_ARCH_NAME:aarch64 = "arm64"
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GN_TARGET_ARCH_NAME:arm = "arm"
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GN_TARGET_ARCH_NAME:x86 = "x86"
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GN_TARGET_ARCH_NAME:x86-64 = "x64"
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def clang_install_path(d):
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"""Return clang compiler install path."""
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return d.getVar("STAGING_BINDIR_NATIVE")
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def gn_target_arch_name(d):
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"""Returns a GN architecture name corresponding to the target machine's
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architecture."""
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name = d.getVar("GN_TARGET_ARCH_NAME")
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if name is None:
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bb.fatal('Unsupported target architecture. A valid override for the '
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'GN_TARGET_ARCH_NAME variable could not be found.')
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return name
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def write_toolchain_file(d, file_path):
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"""Creates a complete GN toolchain file in |file_path|."""
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import string
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# Even though we always use clang, the "clang_toolchain" GN template is too
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# restrictive in the way it sets variables such as |cxx|. Since it is just
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# a wrapper on top of the "gcc_toolchain" template, we keep using the
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# latter directly to accommodate our cross-compilation needs.
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toolchain_tmpl = string.Template(
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'gcc_toolchain("${toolchain_name}") {\n'
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' cc = "${cc}"\n'
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' cxx = "${cxx}"\n'
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' ar = "${ar}"\n'
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' ld = cxx # GN expects a compiler, not a linker.\n'
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' nm = "${nm}"\n'
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' readelf = "${readelf}"\n'
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' extra_cflags = "${extra_cflags}"\n'
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' extra_cppflags = "${extra_cppflags}"\n'
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' extra_cxxflags = "${extra_cxxflags}"\n'
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' extra_ldflags = "${extra_ldflags}"\n'
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' toolchain_args = {\n'
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' current_cpu = "${current_cpu}"\n'
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' current_os = "linux"\n'
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' is_clang = true\n'
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' }\n'
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'}\n'
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)
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native_toolchain = {
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'toolchain_name': 'yocto_native',
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'current_cpu': gn_host_arch_name(d),
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'cc': d.expand('${BUILD_CC}'),
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'cxx': d.expand('${BUILD_CXX}'),
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'ar': d.expand('${BUILD_AR}'),
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'nm': d.expand('${BUILD_NM}'),
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'readelf': d.expand('${BUILD_PREFIX}readelf'),
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'extra_cflags': d.expand('${BUILD_CFLAGS}'),
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'extra_cppflags': d.expand('${BUILD_CPPFLAGS}'),
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'extra_cxxflags': d.expand('${BUILD_CXXFLAGS}'),
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'extra_ldflags': d.expand('${BUILD_LDFLAGS}'),
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}
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target_toolchain = {
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'toolchain_name': 'yocto_target',
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'current_cpu': gn_target_arch_name(d),
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'cc': d.expand('${CC}'),
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'cxx': d.expand('${CXX}'),
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'ar': d.expand('${AR}'),
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'nm': d.expand('${NM}'),
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'readelf': d.expand('${READELF}'),
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'extra_cflags': d.expand('${CFLAGS}'),
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'extra_cppflags': d.expand('${CPPFLAGS}'),
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'extra_cxxflags': d.expand('${CXXFLAGS}'),
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'extra_ldflags': d.expand('${LDFLAGS}'),
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}
|
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with open(file_path, 'w') as toolchain_file:
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toolchain_file.write(
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'# This file has been generated automatically.\n'
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'\n'
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'import("//build/toolchain/gcc_toolchain.gni")\n'
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'\n'
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)
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toolchain_file.write(toolchain_tmpl.substitute(native_toolchain))
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toolchain_file.write(toolchain_tmpl.substitute(target_toolchain))
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