[llvm-nm][RISCV] Recognize mapping symbols

[MaskRay]

special-syms-riscv.test should be better:)

[jobnoorman]

Rename test

llvm/test/tools/llvm-nm/RISCV/special-syms.test

+## Test --special-syms flag.
+# RUN: yaml2obj %s -o %t
+
+# RUN: llvm-nm %t | count 0
+# RUN: llvm-nm %t --special-syms | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_RISCV
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x1000
+  - Name:            .data
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_WRITE ]
+    Address:         0x2000
+Symbols:
+  - Name:     $x.1
+    Section:  .text
+  - Name:     $d.1
+    Section:  .data
+
+# CHECK:      2000 d $d.1
+# CHECK-NEXT: 1000 t $x.1

llvm/tools/llvm-nm/llvm-nm.cpp

for (BasicSymbolRef Sym : Symbols) {
         return false;
       }
 
       // Don't drop format specifc symbols for ARM and AArch64 ELF targets, they
       // are used to repesent mapping symbols and needed to honor the
       // --special-syms option.
       auto *ELFObj = dyn_cast<ELFObjectFileBase>(&Obj);
       bool HasMappingSymbol =
-          ELFObj &&
-          llvm::is_contained({ELF::EM_ARM, ELF::EM_AARCH64, ELF::EM_CSKY},
+          ELFObj && llvm::is_contained({ELF::EM_ARM, ELF::EM_AARCH64,
+                                        ELF::EM_CSKY, ELF::EM_RISCV},
                                        ELFObj->getEMachine());
       if (!HasMappingSymbol && !DebugSyms &&
           (*SymFlagsOrErr & SymbolRef::SF_FormatSpecific))
         continue;
       if (WithoutAliases && (*SymFlagsOrErr & SymbolRef::SF_Indirect))
         continue;
       // If a "-s segname sectname" option was specified and this is a Mach-O
       // file and this section appears in this file, Nsect will be non-zero then
       // see if this symbol is a symbol from that section and if not skip it.