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sd-boot: Let the compiler invoke the linker for us

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For LTO to work, the linker has to be called with some magic sauce arguments.
And the easiest way to get those is to just let the compiler to the job for us.
This commit is contained in:
Jan Janssen 2021-11-08 13:43:55 +01:00
parent 8fb444011e
commit fe330f02df
2 changed files with 42 additions and 22 deletions
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4
meson_options.txt
View file

@ -411,7 +411,9 @@ option('gnu-efi', type : 'combo', choices : ['auto', 'true', 'false'],
description : 'gnu-efi support for sd-boot')
option('efi-cc', type : 'array',
description : 'the compiler to use for EFI modules')
option('efi-ld', type : 'string', value : 'ld',
# Note that LLD does not support PE/COFF relocations
# https://lists.llvm.org/pipermail/llvm-dev/2021-March/149234.html
option('efi-ld', type : 'combo', choices : ['bfd', 'gold'],
description : 'the linker to use for EFI modules')
option('efi-libdir', type : 'string',
description : 'path to the EFI lib directory')

60
src/boot/efi/meson.build
View file

@ -48,14 +48,6 @@ if efi_cc.length() == 0
efi_cc = cc.cmd_array()
endif
efi_ld = find_program(get_option('efi-ld'))
efi_ld_name = efi_ld.path().split('/')[-1]
if efi_ld_name == 'lld' or efi_ld_name == 'ld.lld'
# LLVM/LLD does not support PE/COFF relocations
# https://lists.llvm.org/pipermail/llvm-dev/2021-March/149234.html
error('LLVM/lld does not support PE/COFF relocations. Use different linker for EFI image.')
endif
efi_libdir = ''
foreach dir : [get_option('efi-libdir'),
'/usr/lib/gnuefi' / efi_arch[0],
@ -260,26 +252,52 @@ foreach arg : get_option('c_args')
endif
endforeach
efi_ldflags = ['-T', efi_lds,
'-shared',
'-Bsymbolic',
'-nostdlib',
'--no-undefined',
'--warn-common',
'--fatal-warnings',
'-znocombreloc',
'--build-id=sha1',
'-L', efi_libdir,
efi_crt0]
efi_ldflags = [
'-fuse-ld=' + get_option('efi-ld'),
'-L', efi_libdir,
'-nostdlib',
'-shared',
'-T', efi_lds,
'-Wl,--build-id=sha1',
'-Wl,--fatal-warnings',
'-Wl,--no-undefined',
'-Wl,--warn-common',
'-Wl,-Bsymbolic',
'-z', 'nocombreloc',
efi_crt0,
]
if efi_arch[1] in ['aarch64', 'arm', 'riscv64']
# Aarch64, ARM32 and 64bit RISC-V don't have an EFI capable objcopy.
# Use 'binary' instead, and add required symbols manually.
efi_ldflags += ['--defsym=EFI_SUBSYSTEM=0xa']
efi_ldflags += ['-Wl,--defsym=EFI_SUBSYSTEM=0xa']
efi_format = ['-O', 'binary']
else
efi_format = ['--target=efi-app-@0@'.format(efi_arch[1])]
endif
if run_command('grep', '-q', '__CTOR_LIST__', efi_lds).returncode() == 0
# fedora has a patched gnu-efi that adds support for ELF constructors.
# If ld is called by gcc something about these symbols breaks, resulting
# in sd-boot freezing when gnu-efi runs the constructors. Force defining
# them seems to work around this.
efi_ldflags += [
'-Wl,--defsym=_init_array=0',
'-Wl,--defsym=_init_array_end=0',
'-Wl,--defsym=_fini_array=0',
'-Wl,--defsym=_fini_array_end=0',
'-Wl,--defsym=__CTOR_LIST__=0',
'-Wl,--defsym=__CTOR_END__=0',
'-Wl,--defsym=__DTOR_LIST__=0',
'-Wl,--defsym=__DTOR_END__=0',
]
endif
efi_cc_version = run_command(efi_cc, '--version').stdout().split('\n')[0]
if efi_cc_version.contains('clang') and efi_cc_version.split('.')[0].split(' ')[-1].to_int() <= 10
# clang <= 10 doesn't pass -T to the linker and then even complains about it being unused
efi_ldflags += ['-Wl,-T,' + efi_lds, '-Wno-unused-command-line-argument']
endif
systemd_boot_objects = []
stub_objects = []
foreach file : fundamental_source_paths + common_sources + systemd_boot_sources + stub_sources
@ -308,7 +326,7 @@ foreach tuple : [['systemd_boot.so', systemd_boot_efi_name, systemd_boot_objects
tuple[0],
input : tuple[2],
output : tuple[0],
command : [efi_ld, '-o', '@OUTPUT@', efi_ldflags, tuple[2], '-lefi', '-lgnuefi', libgcc_file_name],
command : [efi_cc, '-o', '@OUTPUT@', efi_ldflags, tuple[2], '-lefi', '-lgnuefi', libgcc_file_name],
install : tuple[3],
install_dir : bootlibdir)