[PATCH] D148385: [RISCV] Implement KCFI operand bundle lowering for RV64

[Sami Tolvanen via Phabricator via cfe-commits]

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Similarly to the target-specific lowering added in D119296 <https://reviews.llvm.org/D119296>, implement
KCFI operand bundle lowering for RV64. Compared to the generic
lowering pass, this ensures we always emit a predictable instruction
sequence for indirect call checks, and that the checks are emitted
immediately before the call.

Note that unlike the generic pass, this patch emits an `ebreak`
instruction for error handling to match the Linux kernel's `BUG()`
implementation. Just like for X86, we also emit trap locations to a
`.kcfi_traps` section as we cannot embed additional information to the
trap instruction itself.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D148385

Files:
  clang/lib/CodeGen/BackendUtil.cpp
  llvm/lib/Target/RISCV/CMakeLists.txt
  llvm/lib/Target/RISCV/RISCV.h
  llvm/lib/Target/RISCV/RISCVAsmPrinter.cpp
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/lib/Target/RISCV/RISCVISelLowering.h
  llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
  llvm/lib/Target/RISCV/RISCVInstrInfo.h
  llvm/lib/Target/RISCV/RISCVInstrInfo.td
  llvm/lib/Target/RISCV/RISCVKCFI.cpp
  llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
  llvm/test/CodeGen/RISCV/O0-pipeline.ll
  llvm/test/CodeGen/RISCV/O3-pipeline.ll
  llvm/test/CodeGen/RISCV/kcfi-patchable-function-prefix.ll
  llvm/test/CodeGen/RISCV/kcfi.ll
  llvm/utils/gn/secondary/llvm/lib/Target/RISCV/BUILD.gn

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