tree 1a3f094bd85ab70e41195015f6d3264fc5480a7e
parent af183e7611cb707ec622c7deef2299fd120fd8cc
author Fangrui Song <maskray@google.com> 1560325986 +0000
committer Fangrui Song <maskray@google.com> 1560325986 +0000

[ELF][RISCV] Treat R_RISCV_{ADD,SET,SUB}* as link-time constants

R_RISCV_{ADD,SET,SUB}* are used for local label computation.
Add a new RelExpr member R_RISCV_ADD to represent them.

R_RISCV_ADD is treated as a link-time constant because otherwise
R_RISCV_{ADD,SET,SUB}* are not allowed in -pie/-shared mode.
In glibc Scrt1.o, .rela.eh_frame contains such relocations.
Because .eh_frame is not writable, we get this error:

    ld.lld: error: can't create dynamic relocation R_RISCV_ADD32 against symbol: .L0 in readonly segment; recompil object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
    >>> defined in ..../riscv64-linux-gnu/lib/Scrt1.o

With D63076 and this patch, I can run -pie/-shared programs linked against glibc.

Note llvm-mc cannot currently produce R_RISCV_SET* so they are not tested.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63183

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@363128 91177308-0d34-0410-b5e6-96231b3b80d8