[llvm-dev] ld.lld drops relocations
David Blaikie via llvm-dev
llvm-dev at lists.llvm.org
Mon Mar 15 15:00:26 PDT 2021
+Fangrui Song <maskray at google.com>
On Mon, Mar 15, 2021 at 2:57 PM Tomasz Gajc via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi,
>
> i'm trying to dig issue with building systemd-boot EFI images with
> llvm/clang and linking with llvm/lld. In general building and linking
> process works and i get my final objects. Unfortunately these EFI images
> does not boot system. I noticed that .efi image is missing PE/COFF
> relocations.
> When i changed linker to ld.bfd, voila everything is fine and final efi
> image does boot system and have needed relocs. I tried all the ld.lld
> options related to relocations, but still no success.
> Thanks for your help.
>
> Below you can find diff between two objdumps.
>
> [root at tpg-latitude5490 /]# cat bootx.linkers.diff
> --- bootx.BFD 2021-03-14 23:33:41.687446710 +0100
> +++ bootx.LLD 2021-03-14 23:33:58.037519874 +0100
> @@ -1,11 +1,12 @@
>
> -systemd-bootx64.efi.BFD: file format pei-x86-64
> -systemd-bootx64.efi.BFD
> -architecture: i386:x86-64, flags 0x00000133:
> -HAS_RELOC, EXEC_P, HAS_SYMS, HAS_LOCALS, D_PAGED
> -start address 0x0000000000003000
> +systemd-bootx64.efi.LLD: file format pei-x86-64
> +systemd-bootx64.efi.LLD
> +architecture: i386:x86-64, flags 0x00000132:
> +EXEC_P, HAS_SYMS, HAS_LOCALS, D_PAGED
> +start address 0x0000000000004000
>
> -Characteristics 0x206
> +Characteristics 0x207
> + relocations stripped
> executable
> line numbers stripped
> debugging information removed
> @@ -14,11 +15,11 @@
> Magic 020b (PE32+)
> MajorLinkerVersion 2
> MinorLinkerVersion 36
> -SizeOfCode 0000000000010000
> -SizeOfInitializedData 0000000000006000
> +SizeOfCode 000000000000f600
> +SizeOfInitializedData 0000000000005e00
> SizeOfUninitializedData 0000000000000000
> -AddressOfEntryPoint 0000000000003000
> -BaseOfCode 0000000000003000
> +AddressOfEntryPoint 0000000000004000
> +BaseOfCode 0000000000004000
> ImageBase 0000000000000000
> SectionAlignment 00001000
> FileAlignment 00000200
> @@ -29,9 +30,9 @@
> MajorSubsystemVersion 0
> MinorSubsystemVersion 0
> Win32Version 00000000
> -SizeOfImage 0001c000
> -SizeOfHeaders 00000400
> -CheckSum 00022f3d
> +SizeOfImage 0001b000
> +SizeOfHeaders 00000370
> +CheckSum 0001b531
> Subsystem 0000000a (EFI application)
> DllCharacteristics 00000000
> SizeOfStackReserve 0000000000000000
> @@ -47,7 +48,7 @@
> Entry 2 0000000000000000 00000000 Resource Directory [.rsrc]
> Entry 3 0000000000000000 00000000 Exception Directory [.pdata]
> Entry 4 0000000000000000 00000000 Security Directory
> -Entry 5 0000000000013000 0000000a Base Relocation Directory [.reloc]
> +Entry 5 0000000000000000 00000000 Base Relocation Directory [.reloc]
> Entry 6 0000000000000000 00000000 Debug Directory
> Entry 7 0000000000000000 00000000 Description Directory
> Entry 8 0000000000000000 00000000 Special Directory
> @@ -59,367 +60,358 @@
> Entry e 0000000000000000 00000000 CLR Runtime Header
> Entry f 0000000000000000 00000000 Reserved
>
> -
> -PE File Base Relocations (interpreted .reloc section contents)
> -
> -Virtual Address: 00004770 Chunk size 10 (0xa) Number of fixups 1
> - reloc 0 offset 0 [4770] ABSOLUTE
> -
> Sections:
> Idx Name Size VMA LMA File off Algn
> - 0 .text 0000ff20 0000000000003000 0000000000003000 00000400 2**4
> - CONTENTS, ALLOC, LOAD, READONLY, CODE
> - 1 .reloc 0000000a 0000000000013000 0000000000013000 00010400 2**0
> + 0 .rela.dyn 00000fa8 0000000000000170 0000000000000170 00000370 2**3
> CONTENTS, ALLOC, LOAD, READONLY, DATA
> - 2 .data 00004460 0000000000014000 0000000000014000 00010600 2**5
> + 1 .text 0000f510 0000000000004000 0000000000004000 00001400 2**4
> + CONTENTS, ALLOC, LOAD, READONLY, CODE
> + 2 .data 00004578 0000000000014000 0000000000014000 00010a00 2**5
> CONTENTS, ALLOC, LOAD, DATA
> - 3 .dynamic 000000f0 0000000000019000 0000000000019000 00014c00 2**3
> + 3 .dynamic 000000a0 0000000000019000 0000000000019000 00015000 2**3
> CONTENTS, ALLOC, LOAD, DATA
> - 4 .rela 00000fa8 000000000001a000 000000000001a000 00014e00 2**3
> - CONTENTS, ALLOC, LOAD, READONLY, DATA
> - 5 .dynsym 000004e0 000000000001b000 000000000001b000 00015e00 2**3
> + 4 .dynsym 00000450 000000000001a000 000000000001a000 00015200 2**3
> CONTENTS, ALLOC, LOAD, READONLY, DATA
>
>
>
> 1. [systemd issue] - https://github.com/systemd/systemd/issues/19005
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210315/bd234617/attachment.html>
More information about the llvm-dev
mailing list