[AArch64] Unconditionally use DW_EH_PE_indirect|DW_EH_PE_pcrel personality/lsda/ttype...
authorFangrui Song <i@maskray.me>
Sun, 5 Feb 2023 18:46:43 +0000 (10:46 -0800)
committerFangrui Song <i@maskray.me>
Sun, 5 Feb 2023 18:46:43 +0000 (10:46 -0800)
commitca65969c3ea0ad3db31e8b3646b960c75ef5f6c8
tree7d6873708fb40422e4abafe5e67a64343a758ea5
parent90094ab8850ec435574fbd393d886a54a6dd2531
[AArch64] Unconditionally use DW_EH_PE_indirect|DW_EH_PE_pcrel personality/lsda/ttype encodings

For -fno-pic, without DW_EH_PE_indirect, the personality routine pointer in a
CIE needs an R_AARCH64_ABS64 relocation. In common configurations that
`__gcc_personality_v0` is defined in a shared object, this will lead to a
discouraged canonical PLT entry, or, if `ld.lld -z notext` (betwen D122459 and
D143136), a dynamic R_AARCH64_ABS64 relocation with an incorrect offset:
https://github.com/llvm/llvm-project/issues/60392

Since GCC uses DW_EH_PE_indirect for -fno-pic code (the behavior hasn't changed
since the initial port in 2012), let's follow suit by simplifying the code.
(
For tiny and small code models, we use DW_EH_PE_sdata8 instead of GCC's
DW_EH_PE_sdata4. This is a deliberate choice to support personality-.eh_frame
offset > 2GiB. This is unneeded for small code model since "Max text segment
size < 2GiB" but making `-fno-pic -mcmodel={tiny,small}` different seems
unnecessary: the scenarios that uses both -fno-pic and C++ exceptions have been
increasingly rare now, so there is little advantage optimizing for the little
size saving with code complexity.
)

---

Two clang/test/Interpreter tests would fail without 6747fc07d1aa94e22622e278e5a02ba70675ac9b
([ORC] Use JITLink as the default linker for LLJIT on Linux/arm64.)

Reviewed By: MatzeB

Differential Revision: https://reviews.llvm.org/D143039
llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
llvm/test/CodeGen/AArch64/arm64-big-endian-eh.ll
llvm/test/CodeGen/AArch64/pic-eh-stubs.ll
llvm/test/DebugInfo/AArch64/eh_frame_personality.ll
llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll