jrtc27 added a comment.
I am still of the view that we should support rewriting the instruction stream
in the linker when necessary like BFD does. We need to do this to be able to
link in GCC-compiled code, including libraries. It is a very simple thing to do
with a patch available that provides consistency between the GNU world and the
LLVM world.
================
Comment at: llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp:680
+ if (MF->getTarget().isPositionIndependent() ||
+ MF->getTarget().getCodeModel() != CodeModel::Small) {
const auto &STI = MF->getSubtarget<RISCVSubtarget>();
----------------
This is confusing and differs from when you invoke the assembler manually, even
via the Clang driver with the right code model specified. Any `la`s there will
be assembled as `AUIPC`/`ADDI`. I am of the view it was a mistake to make
`la`'s behaviour conditional on PICness and it should have always used the GOT,
but this is what we have.
================
Comment at: llvm/lib/Target/TargetMachine.cpp:192
return false;
+ // RISC-V non-small code models prefer avoiding copy relocations.
+ if (TT.isRISCV() && getCodeModel() != CodeModel::Small)
----------------
Are we sure we want to do this and take the performance hit over GCC due to the
extra level of indirection on every single extern global access? If this is the
solution to take for extern weak, I think we should limit it to just that and
have a separate discussion about non-extern-weak.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D72056/new/
https://reviews.llvm.org/D72056
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