[cheriot] Enable RVE elf flag for cheriot ABIs

This must match other objects that have `EF_RISCV_RVE` set in their ELF
header. CHERIoT targets use XLEN=16 (E).

Author: jwnrt

llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp

@@ -109,8 +109,6 @@ void RISCVTargetELFStreamer::finish() {
     break;
   case RISCVABI::ABI_IL32PC64:
   case RISCVABI::ABI_L64PC128:
-  case RISCVABI::ABI_CHERIOT:
-  case RISCVABI::ABI_CHERIOT_BAREMETAL:
     EFlags |= ELF::EF_RISCV_CHERIABI;
     break;
   case RISCVABI::ABI_ILP32F:
@@ -136,6 +134,8 @@ void RISCVTargetELFStreamer::finish() {
     EFlags |= ELF::EF_RISCV_RVE;
     break;
   case RISCVABI::ABI_IL32PC64E:
+  case RISCVABI::ABI_CHERIOT:
+  case RISCVABI::ABI_CHERIOT_BAREMETAL:
     EFlags |= ELF::EF_RISCV_RVE;
     EFlags |= ELF::EF_RISCV_CHERIABI;
     break;

llvm/test/Object/RISCV/cheriot-elf-flags.ll

@@ -0,0 +1,4 @@
+; RUN: llc --filetype=obj -mtriple=riscv32-unknown-unknown -mcpu=cheriot -target-abi cheriot %s -o - | llvm-readelf --file-header - | FileCheck %s
+
+; Ensure CHERIoT targets have the correct ELF flags.
+; CHECK: Flags: 0x30009, RVC, RVE, cheriabi, capability mode