[llvm] [llvm-exegesis] [AArch64] Resolving "not all operands are initialized by snippet generator" (PR #142529)

[Sjoerd Meijer via llvm-commits]

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@@ -229,6 +233,41 @@ class ExegesisAArch64Target : public ExegesisTarget {
   }
 };
 
+Error ExegesisAArch64Target::randomizeTargetMCOperand(
+    const Instruction &Instr, const Variable &Var, MCOperand &AssignedValue,
+    const BitVector &ForbiddenRegs) const {
+  const Operand &Op = Instr.getPrimaryOperand(Var);
+  const auto OperandType = Op.getExplicitOperandInfo().OperandType;
+  // TODO: Look into immediate values to be opcode specific for
+  // MRS, MSR, MSRpstatesvcrImm1, SYSLxt, SYSxt, UDF (illegal instruction)
+  switch (OperandType) {
+  case MCOI::OperandType::OPERAND_UNKNOWN: {
+    unsigned Opcode = Instr.getOpcode();
+    switch (Opcode) {
+    case AArch64::MOVIv2s_msl:
+    case AArch64::MOVIv4s_msl:
+    case AArch64::MVNIv2s_msl:
+    case AArch64::MVNIv4s_msl:
+      AssignedValue = MCOperand::createImm(8); // or 16
+      return Error::success();
+    default:
+      AssignedValue = MCOperand::createImm(0);
+      return Error::success();
+    }
+  }
+  case MCOI::OperandType::OPERAND_PCREL:
+  case MCOI::OperandType::OPERAND_FIRST_TARGET:
+    AssignedValue = MCOperand::createImm(0);
+    return Error::success();
+  default:
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sjoerdmeijer wrote:

I was wondering what we want to do for the default case. Does this mean we silently ignore OperandType that we might want to support in the future? Do we want to emit a warning?

https://github.com/llvm/llvm-project/pull/142529