[clang] [compiler-rt] [llvm] [XRay][RISCV] RISCV support for XRay (PR #117368)

[Craig Topper via llvm-commits]

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@@ -1575,6 +1575,26 @@ unsigned RISCVInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
     // No patch bytes means at most a PseudoCall is emitted
     return std::max(NumBytes, 8U);
   }
+  case TargetOpcode::PATCHABLE_FUNCTION_ENTER:
+  case TargetOpcode::PATCHABLE_FUNCTION_EXIT:
+  case TargetOpcode::PATCHABLE_TAIL_CALL: {
+    const MachineFunction &MF = *MI.getParent()->getParent();
+    const Function &F = MF.getFunction();
+    if (Opcode == TargetOpcode::PATCHABLE_FUNCTION_ENTER &&
+        F.hasFnAttribute("patchable-function-entry")) {
+      unsigned Num;
+      if (F.getFnAttribute("patchable-function-entry")
+              .getValueAsString()
+              .getAsInteger(10, Num))
+        return get(Opcode).getSize();
+
+      // Number of C.NOP or NOP
+      return (STI.hasStdExtCOrZca() ? 2 : 4) * Num;
+    }
+    // XRay uses C.JAL + 25 or 33 C.NOP for each sled in RV32 and RV64,
+    // respectively.
+    return STI.is64Bit() ? 68 : 52;
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topperc wrote:

should 52 be 44?

https://github.com/llvm/llvm-project/pull/117368