[CHERIoT] Teach LLDB to read CHERI & CHERIoT features from ELF files.

Author: resistor

lldb/include/lldb/Utility/ArchSpec.h

@@ -99,6 +99,9 @@ class ArchSpec {
     eRISCV_float_abi_mask   = 0x00000006,
     eRISCV_rve              = 0x00000008, /// RVE, +e
     eRISCV_tso              = 0x00000010, /// RVTSO (total store ordering)
+    eRISCV_cheri_abi        = 0x10000000,
+    eRISCV_cap_mode         = 0x20000000,
+    eRISCV_cheriot          = 0x40000000,
   };
 
   enum RISCVSubType {

lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp

@@ -1577,6 +1577,12 @@ DisassemblerLLVMC::DisassemblerLLVMC(const ArchSpec &arch,
     if ((arch_flags & ArchSpec::eRISCV_float_abi_quad) ==
         ArchSpec::eRISCV_float_abi_quad)
       features_str += "+f,+d,+q,";
+    if ((arch_flags & ArchSpec::eRISCV_cheri_abi) == ArchSpec::eRISCV_cheri_abi)
+      features_str += "+xcheri,";
+    if ((arch_flags & ArchSpec::eRISCV_cap_mode) == ArchSpec::eRISCV_cap_mode)
+      features_str += "+cap-mode,";
+    if ((arch_flags & ArchSpec::eRISCV_cheriot) == ArchSpec::eRISCV_cheriot)
+      features_str += "+xcheriot,";
     // FIXME: how do we detect features such as `+a`, `+m`?
     // Turn them on by default now, since everyone seems to use them
     features_str += "+a,+m,";

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

@@ -1433,6 +1433,16 @@ size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
              llvm::ELF::EF_RISCV_FLOAT_ABI_QUAD)
       flags |= ArchSpec::eRISCV_float_abi_quad;
 
+    if ((header.e_flags & llvm::ELF::EF_RISCV_CHERIABI) ==
+        llvm::ELF::EF_RISCV_CHERIABI)
+      flags |= ArchSpec::eRISCV_cheri_abi;
+    if ((header.e_flags & llvm::ELF::EF_RISCV_CAP_MODE) ==
+        llvm::ELF::EF_RISCV_CAP_MODE)
+      flags |= ArchSpec::eRISCV_cap_mode;
+    if ((header.e_flags & llvm::ELF::EF_RISCV_CHERIOT) ==
+        llvm::ELF::EF_RISCV_CHERIOT)
+      flags |= ArchSpec::eRISCV_cheriot;
+
     arch_spec.SetFlags(flags);
   }