diff --git a/lldb/include/lldb/Utility/ArchSpec.h b/lldb/include/lldb/Utility/ArchSpec.h
--- a/lldb/include/lldb/Utility/ArchSpec.h
+++ b/lldb/include/lldb/Utility/ArchSpec.h
@@ -99,6 +99,12 @@
     eRISCV_abi_d = 0x00000020
   };
 
+  enum RISCVSubType {
+    eRISCVSubType_unknown,
+    eRISCVSubType_riscv32,
+    eRISCVSubType_riscv64,
+  };
+
   enum Core {
     eCore_arm_generic,
     eCore_arm_armv4,
diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -296,9 +296,23 @@
   return arch_variant;
 }
 
+static uint32_t riscvVariantFromElfFlags(const elf::ELFHeader &header) {
+  uint32_t fileclass = header.e_ident[EI_CLASS];
+  switch (fileclass) {
+  case llvm::ELF::ELFCLASS32:
+    return ArchSpec::eRISCVSubType_riscv32;
+  case llvm::ELF::ELFCLASS64:
+    return ArchSpec::eRISCVSubType_riscv64;
+  default:
+    return ArchSpec::eRISCVSubType_unknown;
+  }
+}
+
 static uint32_t subTypeFromElfHeader(const elf::ELFHeader &header) {
   if (header.e_machine == llvm::ELF::EM_MIPS)
     return mipsVariantFromElfFlags(header);
+  else if (header.e_machine == llvm::ELF::EM_RISCV)
+    return riscvVariantFromElfFlags(header);
 
   return LLDB_INVALID_CPUTYPE;
 }
diff --git a/lldb/source/Utility/ArchSpec.cpp b/lldb/source/Utility/ArchSpec.cpp
--- a/lldb/source/Utility/ArchSpec.cpp
+++ b/lldb/source/Utility/ArchSpec.cpp
@@ -457,10 +457,10 @@
      0xFFFFFFFFu, 0xFFFFFFFFu}, // ARC
     {ArchSpec::eCore_avr, llvm::ELF::EM_AVR, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // AVR
-    {ArchSpec::eCore_riscv32, llvm::ELF::EM_RISCV, LLDB_INVALID_CPUTYPE,
-     0xFFFFFFFFu, 0xFFFFFFFFu}, // riscv32
-    {ArchSpec::eCore_riscv64, llvm::ELF::EM_RISCV, LLDB_INVALID_CPUTYPE,
-     0xFFFFFFFFu, 0xFFFFFFFFu}, // riscv64
+    {ArchSpec::eCore_riscv32, llvm::ELF::EM_RISCV,
+     ArchSpec::eRISCVSubType_riscv32, 0xFFFFFFFFu, 0xFFFFFFFFu}, // riscv32
+    {ArchSpec::eCore_riscv64, llvm::ELF::EM_RISCV,
+     ArchSpec::eRISCVSubType_riscv64, 0xFFFFFFFFu, 0xFFFFFFFFu}, // riscv64
 };
 
 static const ArchDefinition g_elf_arch_def = {
diff --git a/lldb/test/Shell/ObjectFile/ELF/riscv64-arch.yaml b/lldb/test/Shell/ObjectFile/ELF/riscv64-arch.yaml
new file mode 100644
--- /dev/null
+++ b/lldb/test/Shell/ObjectFile/ELF/riscv64-arch.yaml
@@ -0,0 +1,11 @@
+# RUN: yaml2obj %s > %t
+# RUN: lldb-test object-file %t | FileCheck %s
+
+# CHECK: Architecture: riscv64--
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_RISCV