From da7b129b1b52bdc52b02b546b75f90fad07f6d3a Mon Sep 17 00:00:00 2001 From: James Clarke Date: Tue, 3 Dec 2019 22:04:24 +0000 Subject: [RISCV] Don't force Local Exec TLS for non-PIC Summary: Forcing Local Exec TLS requires the use of copy relocations. Copy relocations need special handling in the runtime linker when being used against TLS symbols, which is present in glibc, but not in FreeBSD nor musl, and so cannot be relied upon. Moreover, copy relocations are a hack that embed the size of an object in the ABI when it otherwise wouldn't be, and break protected symbols (which are expected to be DSO local), whilst also wasting space, thus they should be avoided whenever possible. As discussed in D70398, RISC-V should move away from forcing Local Exec, and instead use Initial Exec like other targets, with possible linker relaxation to follow. The RISC-V GCC maintainers also intend to adopt this more-conventional behaviour (see https://github.com/riscv/riscv-elf-psabi-doc/issues/122). Reviewers: asb, MaskRay Reviewed By: MaskRay Subscribers: emaste, krytarowski, hiraditya, rbar, johnrusso, simoncook, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, llvm-commits, bsdjhb Tags: #llvm Differential Revision: https://reviews.llvm.org/D70649 --- llvm/lib/Target/RISCV/RISCVISelLowering.cpp | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'llvm/lib/Target/RISCV') diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp index b9aa5cf32b5..1e562f3f54b 100644 --- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp +++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp @@ -581,10 +581,7 @@ SDValue RISCVTargetLowering::lowerGlobalTLSAddress(SDValue Op, int64_t Offset = N->getOffset(); MVT XLenVT = Subtarget.getXLenVT(); - // Non-PIC TLS lowering should always use the LocalExec model. - TLSModel::Model Model = isPositionIndependent() - ? getTargetMachine().getTLSModel(N->getGlobal()) - : TLSModel::LocalExec; + TLSModel::Model Model = getTargetMachine().getTLSModel(N->getGlobal()); SDValue Addr; switch (Model) { -- cgit v1.2.3