[PATCH] D102862: [lld][ELF][SPARC] Support TLS GD relocations
Jessica Clarke via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu May 20 12:17:40 PDT 2021
jrtc27 added inline comments.
================
Comment at: lld/ELF/Arch/SPARCV9.cpp:212-217
+ case R_SPARC_TLS_GD_HI22:
+ relocateNoSym(loc, R_SPARC_HI22, val);
+ return;
+ case R_SPARC_TLS_GD_LO10:
+ relocateNoSym(loc, R_SPARC_LO10, val);
+ return;
----------------
R_SPARC_TLS_IE_HI22/LO10? This is wrong, but I guess this is a hack that kinda works because IE isn't actually implemented yet? Which probably should happen before landing GD support... LD is less clear, but also seemingly unimplemented, only basic LE.
================
Comment at: lld/ELF/Arch/SPARCV9.cpp:227
+ case R_SPARC_TLS_GD_ADD:
+ // add %r1, %r2, %r3 -> mov %g7, %r2, %r3
+ write32be(loc, (read32be(loc) & ~0x0007c000) | 0x0001c000);
----------------
Do you mean `add %g7, %r2, %r3`?
================
Comment at: lld/ELF/Driver.cpp:929
return m == EM_AARCH64 || m == EM_AMDGPU || m == EM_HEXAGON || m == EM_PPC ||
- m == EM_PPC64 || m == EM_RISCV || m == EM_X86_64;
+ m == EM_PPC64 || m == EM_RISCV || m == EM_X86_64 || m == EM_SPARCV9;
}
----------------
Please keep this sorted
================
Comment at: lld/ELF/Relocations.cpp:291-294
+ // These relocations are applied on call instructions like
+ // call __tls_get_addr, %rel(sym)
+ // If this relocation won't be relaxed we have to replace it with a
+ // PLT-relative one to __tls_get_addr.
----------------
Should this be more like hexagonNeedsTLSSymbol/hexagonTLSSymbolUpdate and combined with it, which has similar weirdness?
================
Comment at: lld/ELF/Relocations.cpp:298-299
+
+ if (!call_sym->isInGot())
+ addGotEntry(*call_sym);
+ if (!call_sym->isInPlt())
----------------
Why would it need a GOT entry? SPARC doesn't even use a .got.plt, it synthesises the addresses directly in the PLT entries, but even on .got.plt architectures calls don't use the real GOT other than MIPS abicalls.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D102862/new/
https://reviews.llvm.org/D102862
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