# -*- mode: python -*-

Import("env")
Import("has_option")
Import("debugBuild")

# https://www.nongnu.org/libunwind/man/libunwind(3).html#section_1
# For local unwinding (introspection, which is all we want), include
# libunwind.h and link with '-lunwind'. We only need to build enough
# for that to work.
#
# Supported:
#      linux_x86_64
#      linux_aarch64

env = env.Clone(
    # Libunwind wants to interpose (for better or for worse) on the
    # libc `backtrace`. Building with hidden visibility probably
    # breaks that. It also seems to interfere with building with the
    # sanitizers, which use linker maps that reference backtrace. This
    # may be an ld.gold bug.
    DISALLOW_VISHIDDEN=True, )

unwind_root = env.Dir(".").srcnode()
unwind_platform = unwind_root.Dir("platform/${TARGET_OS}_${TARGET_ARCH}")
unwind_src_dir = env.Dir("dist/src")

if env['TARGET_ARCH'] == 'ppc64le':
    env['UNWIND_TARGET_ARCH'] = 'ppc64'
    env['UNWIND_TARGET_ARCH_ALT'] = 'ppc'
else:
    env['UNWIND_TARGET_ARCH'] = env['TARGET_ARCH']
    env['UNWIND_TARGET_ARCH_ALT'] = env['TARGET_ARCH']

# Generated by a manual process:
#     - Run "scripts/host_config.sh |tee host_config.out".
#     - Gather .o dependencies of the libunwind.a target.
#     - Some .o are from prereq libraries, they have .lax paths.
#       Replace the `*.lax/$PREREQ/*.o` dependencies with the
#       corresponding .o from that $PREREQ library.
#     - Replace each .o with the source file (.c or .S) that generated it.
#     - Ensure the the ${CC} arguments are preserved by SCons.
#       Note you can skip NDEBUG defines as those should be inherited.
unwind_common_sources = [
    'dwarf/global.c',
    'dwarf/Lexpr.c',
    'dwarf/Lfde.c',
    'dwarf/Lfind_proc_info-lsb.c',
    'dwarf/Lfind_unwind_table.c',
    'dwarf/Lparser.c',
    'dwarf/Lpe.c',
    "dl-iterate-phdr.c",
    'elf64.c',
    'mi/backtrace.c',
    'mi/dyn-cancel.c',
    'mi/dyn-info-list.c',
    'mi/dyn-register.c',
    'mi/flush_cache.c',
    'mi/init.c',
    'mi/Ldestroy_addr_space.c',
    'mi/Ldyn-extract.c',
    'mi/Lfind_dynamic_proc_info.c',
    'mi/Lget_accessors.c',
    'mi/Lget_fpreg.c',
    'mi/Lget_proc_info_by_ip.c',
    'mi/Lget_proc_name.c',
    'mi/Lget_reg.c',
    'mi/Lput_dynamic_unwind_info.c',
    'mi/Lset_cache_size.c',
    'mi/Lset_caching_policy.c',
    'mi/Lset_fpreg.c',
    'mi/Lset_reg.c',
    'mi/mempool.c',
    'mi/strerror.c',
    'os-${TARGET_OS}.c',
]

unwind_platform_sources = [
    '${UNWIND_TARGET_ARCH}/is_fpreg.c',
    '${UNWIND_TARGET_ARCH}/Lapply_reg_state.c',
    '${UNWIND_TARGET_ARCH}/Lcreate_addr_space.c',
    '${UNWIND_TARGET_ARCH_ALT}/Lget_proc_info.c',
    '${UNWIND_TARGET_ARCH_ALT}/Lget_save_loc.c',
    '${UNWIND_TARGET_ARCH}/Lglobal.c',
    '${UNWIND_TARGET_ARCH}/Linit.c',
    '${UNWIND_TARGET_ARCH_ALT}/Linit_local.c',
    '${UNWIND_TARGET_ARCH_ALT}/Linit_remote.c',
    '${UNWIND_TARGET_ARCH}/Lregs.c',
    '${UNWIND_TARGET_ARCH}/Lreg_states_iterate.c',
    '${UNWIND_TARGET_ARCH}/Lresume.c',
    '${UNWIND_TARGET_ARCH}/Lstep.c',
    '${UNWIND_TARGET_ARCH}/regname.c',
]

if env['TARGET_ARCH'] == 'x86_64':
    unwind_platform_sources += [
        "${UNWIND_TARGET_ARCH}/Los-${TARGET_OS}.c",
        '${UNWIND_TARGET_ARCH}/Lstash_frame.c',
        '${UNWIND_TARGET_ARCH}/Ltrace.c',
        "${UNWIND_TARGET_ARCH}/getcontext.S",
        "${UNWIND_TARGET_ARCH}/setcontext.S",
    ]
elif env['TARGET_ARCH'] == 'aarch64':
    unwind_platform_sources += [
        "${UNWIND_TARGET_ARCH}/Lis_signal_frame.c",
        "${UNWIND_TARGET_ARCH}/Lstash_frame.c",
        "${UNWIND_TARGET_ARCH}/Ltrace.c",
        "${UNWIND_TARGET_ARCH}/getcontext.S",
    ]
elif env['TARGET_ARCH'] == 'ppc64le':
    unwind_platform_sources += [
        "${UNWIND_TARGET_ARCH}/get_func_addr.c",
        "${UNWIND_TARGET_ARCH_ALT}/Lis_signal_frame.c",
    ]
elif env['TARGET_ARCH'] == 's390x':
    unwind_platform_sources += [
        "${UNWIND_TARGET_ARCH}/Lis_signal_frame.c",
        "${UNWIND_TARGET_ARCH}/getcontext.S",
        "${UNWIND_TARGET_ARCH}/setcontext.S",
    ]
else:
    env.FatalError(f"{env['TARGET_ARCH']} unsupported by libunwind.")

env.Append(CCFLAGS=[
    '-fexceptions',
    '-Wno-unused-result',
    '-Wno-pointer-sign',
    '-Wno-incompatible-pointer-types',
    '-Wno-unused-variable',
])

if env.ToolchainIs('gcc'):
    env.Append(CCFLAGS=[
        '-Wno-uninitialized',
    ])

if env['TARGET_ARCH'] == 'ppc64le':
    env.Append(CCFLAGS=[
        '-Wno-unused-value',
    ])

if env.ToolchainIs('clang'):
    env.Append(CCFLAGS=['-Wno-header-guard'])
    if env['TARGET_ARCH'] == 'aarch64':
        env.Append(CCFLAGS=['-Wno-absolute-value'])

env.Append(CPPPATH=[
    unwind_platform.Dir("build/include"),
    unwind_root.Dir("dist/src"),
    unwind_root.Dir("dist/include"),
    unwind_root.Dir("dist/include/tdep-${UNWIND_TARGET_ARCH}"),
])

# propagates to consumers that inject (depend on) unwind.
env.RegisterConsumerModifications(
    CPPPATH=[unwind_platform.Dir("install/include")],
    SYSLIBDEPS_PRIVATE=[env['LIBDEPS_LZMA_SYSLIBDEP']],
)

env.Append(SYSLIBDEPS_PRIVATE=[env['LIBDEPS_LZMA_SYSLIBDEP']])

env.Append(CPPDEFINES=[
    'HAVE_CONFIG_H',
    '_GNU_SOURCE',
])

unwind_sources = unwind_common_sources + unwind_platform_sources

env.Library(
    target='unwind',
    source=env.File(unwind_sources, unwind_src_dir),
)