[llvm] [Exegesis][RISCV] Add RISCV support for llvm-exegesis (PR #89047)

[Keeran Rothenfusser via llvm-commits]

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@@ -86,6 +86,16 @@ class ExegesisTarget {
                 ArrayRef<const char *> ValidationCounters,
                 const pid_t ProcessID = 0) const;
 
+  virtual bool checkOpcodeSupported(int Opcode,
+                                    const MCSubtargetInfo &SI) const {
+    return true;
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keeranroth wrote:

Should this default to false? If we don't know what target or opcode we are dealing with, I would assume that false is the default to go for. Similarly to returning NoRegister by default below

https://github.com/llvm/llvm-project/pull/89047