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Merge commit da7b129b1 from llvm git (by James Clarke):

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[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

This is a prerequisite for building and linking hard- and soft-float
riscv worlds with clang and lld.

Requested by:	jhb
MFC after:	1 week
X-MFC-With:	r353358
This commit is contained in:
Dimitry Andric 2020-01-03 20:11:40 +00:00
parent 8f6d9a8e68
commit 5c72868c4c
1 changed files with 1 additions and 4 deletions
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5
contrib/llvm-project/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
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@ -570,10 +570,7 @@ 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) {