Implement EmitJMP case in RiscV64Emitter (#111273)

Author: am11

src/coreclr/tools/Common/Compiler/DependencyAnalysis/ObjectDataBuilder.cs

@@ -301,6 +301,7 @@ public void EmitReloc(ISymbolNode symbol, RelocType relocType, int delta = 0)
                 case RelocType.IMAGE_REL_BASED_LOONGARCH64_JIR:
 
                 case RelocType.IMAGE_REL_BASED_RISCV64_PC:
+                case RelocType.IMAGE_REL_BASED_RISCV64_JALR:
                     Debug.Assert(delta == 0);
                     // Do not vacate space for this kind of relocation, because
                     // the space is embedded in the instruction.

src/coreclr/tools/Common/Compiler/DependencyAnalysis/Target_RiscV64/RiscV64Emitter.cs

@@ -98,21 +98,22 @@ public void EmitJMP(ISymbolNode symbol)
         {
             if (symbol.RepresentsIndirectionCell)
             {
-                //auipc x29, 0
+                // auipc x29, 0
                 EmitPC(Register.X29);
-                //ld x29,16(x29)
+                // ld x29,16(x29)
                 EmitLD(Register.X29, Register.X29, 16);
-                //ld x29,0(x29)
+                // ld x29,0(x29)
                 EmitLD(Register.X29, Register.X29, 0);
-                //jalr x0,0(x29)
+                // jalr x0,0(x29)
                 EmitJALR(Register.X0, Register.X29, 0);
 
                 Builder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_DIR64);
             }
             else
             {
-                Builder.EmitUInt(0x00000000); // bad code.
-                throw new NotImplementedException();
+                Builder.EmitReloc(symbol, RelocType.IMAGE_REL_BASED_RISCV64_JALR);
+                EmitPC(Register.X29); // auipc x29, 0
+                EmitJALR(Register.X0, Register.X29, 0); // jalr x0, 0(x29)
             }
         }