[VLIWMachineScheduler] Disable default copy ctor and copy assignment operator for VLIWSchedBoundary

[yubing]

Summary

class VLIWSchedBoundary manages resources such as dynamically allocated memory, it's generally a good practice to either implement a custom copy constructor or disable the default one.

[JamesNagurne]

llvm/include/llvm/CodeGen/VLIWMachineScheduler.h

155

What is the reasoning here? It's not obvious to me.

[yubing]

llvm/include/llvm/CodeGen/VLIWMachineScheduler.h

155

class VLIWSchedBoundary manages resources such as dynamically allocated memory, it's generally a good practice to either implement a custom copy constructor or disable the default one.

[JamesNagurne]

llvm/include/llvm/CodeGen/VLIWMachineScheduler.h

155

Understood! Was just curious if there was any other motive. LGTM

llvm/include/llvm/CodeGen/VLIWMachineScheduler.h

struct VLIWSchedBoundary {
 
     /// Pending queues extend the ready queues with the same ID and the
     /// PendingFlag set.
     VLIWSchedBoundary(unsigned ID, const Twine &Name)
         : Available(ID, Name + ".A"),
           Pending(ID << ConvergingVLIWScheduler::LogMaxQID, Name + ".P") {}
 
     ~VLIWSchedBoundary();
+    VLIWSchedBoundary &operator=(const VLIWSchedBoundary &other) = delete;
+    VLIWSchedBoundary(const VLIWSchedBoundary &other) = delete;
 
     void init(VLIWMachineScheduler *dag, const TargetSchedModel *smodel) {
       DAG = dag;
       SchedModel = smodel;
       CurrCycle = 0;
       IssueCount = 0;
       // Initialize the critical path length limit, which used by the scheduling
       // cost model to determine the value for scheduling an instruction. We use