User Config: Add option to specify wall clock CNTPCT.

src/frontend/A64/translate/impl/system.cpp

@@ -120,7 +120,7 @@ bool TranslatorVisitor::MRS(Imm<1> o0, Imm<3> op1, Imm<4> CRn, Imm<4> CRm, Imm<3
         return true;
     case SystemRegisterEncoding::CNTPCT_EL0:
         // HACK: Ensure that this is the first instruction in the block it's emitted in, so the cycle count is most up-to-date.
-        if (!ir.block.empty()) {
+        if (!ir.block.empty() && !options.wall_clock_cntpct) {
             ir.block.CycleCount()--;
             ir.SetTerm(IR::Term::LinkBlock{*ir.current_location});
             return false;

src/frontend/A64/translate/translate.h

@@ -26,6 +26,10 @@ struct TranslationOptions {
     /// If this is true, we define some behaviour for some instructions.
     bool define_unpredictable_behaviour = false;
 
+    /// This tells the translator a wall clock will be used, thus allowing it
+    /// to avoid writting certain unnecessary code only needed for cycle timers.
+    bool wall_clock_cntpct = false;
+
     /// This changes what IR we emit when we translate a hint instruction.
     /// If this is false, we treat the instruction as a NOP.
     /// If this is true, we emit an ExceptionRaised instruction.