[llvm] [feature][riscv] handle target address calculation in llvm-objdump disassembly for riscv (PR #109914)

[Craig Topper via llvm-commits]

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@@ -230,6 +246,97 @@ class RISCVMCInstrAnalysis : public MCInstrAnalysis {
     return false;
   }
 
+  bool evaluateInstruction(const MCInst &Inst, uint64_t Addr, uint64_t Size,
+                           uint64_t &Target) const override {
+    switch(Inst.getOpcode()) {
+      default:
+        return false;
+      case RISCV::ADDI: {
+        if (auto TargetRegState = getGPRState(Inst.getOperand(1).getReg())) {
+          // TODO: Figure out ways to find the actual value of XLEN during analysis
+          int XLEN = 32;
+          uint64_t Mask = ~((uint64_t)0) >> (64 - XLEN);
+          Target = *TargetRegState + SignExtend64<12>(Inst.getOperand(2).getImm());
+          Target &= Mask;
+          return true;
+        }
+        break;
+      }
+      case RISCV::ADDIW: {
+        if (auto TargetRegState = getGPRState(Inst.getOperand(1).getReg())) {
+          uint64_t Mask = ~((uint64_t)0) >> 32;
+          Target  = *TargetRegState + SignExtend64<12>(Inst.getOperand(2).getImm());
+          Target &= Mask;
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topperc wrote:

Why is this `&=` line needed?

https://github.com/llvm/llvm-project/pull/109914