Use the new getRegAllocationHints() hook from AllocationOrder.

This simplifies the hinting code quite a bit while making the targets
easier to write at the same time.

llvm-svn: 169173

lib/CodeGen/AllocationOrder.cpp

@@ -14,10 +14,15 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define DEBUG_TYPE "regalloc"
 #include "AllocationOrder.h"
+#include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterClassInfo.h"
 #include "llvm/CodeGen/VirtRegMap.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
@@ -25,56 +30,36 @@ using namespace llvm;
 AllocationOrder::AllocationOrder(unsigned VirtReg,
                                  const VirtRegMap &VRM,
                                  const RegisterClassInfo &RegClassInfo)
-  : Begin(0), End(0), Pos(0), RCI(RegClassInfo), OwnedBegin(false) {
-  const TargetRegisterClass *RC = VRM.getRegInfo().getRegClass(VirtReg);
-  std::pair<unsigned, unsigned> HintPair =
-    VRM.getRegInfo().getRegAllocationHint(VirtReg);
-  const MachineRegisterInfo &MRI = VRM.getRegInfo();
+  : Pos(0) {
+  const MachineFunction &MF = VRM.getMachineFunction();
+  const TargetRegisterInfo *TRI = &VRM.getTargetRegInfo();
+  Order = RegClassInfo.getOrder(MF.getRegInfo().getRegClass(VirtReg));
+  TRI->getRegAllocationHints(VirtReg, Order, Hints, MF, &VRM);
 
-  // HintPair.second is a register, phys or virt.
-  Hint = HintPair.second;
-
-  // Translate to physreg, or 0 if not assigned yet.
-  if (TargetRegisterInfo::isVirtualRegister(Hint))
-    Hint = VRM.getPhys(Hint);
-
-  // The first hint pair component indicates a target-specific hint.
-  if (HintPair.first) {
-    const TargetRegisterInfo &TRI = VRM.getTargetRegInfo();
-    // The remaining allocation order may depend on the hint.
-    ArrayRef<MCPhysReg> Order =
-      TRI.getRawAllocationOrder(RC, HintPair.first, Hint,
-                                VRM.getMachineFunction());
-    if (Order.empty())
-      return;
-
-    // Copy the allocation order with reserved registers removed.
-    OwnedBegin = true;
-    MCPhysReg *P = new MCPhysReg[Order.size()];
-    Begin = P;
-    for (unsigned i = 0; i != Order.size(); ++i)
-      if (!MRI.isReserved(Order[i]))
-        *P++ = Order[i];
-    End = P;
-
-    // Target-dependent hints require resolution.
-    Hint = TRI.ResolveRegAllocHint(HintPair.first, Hint,
-                                   VRM.getMachineFunction());
-  } else {
-    // If there is no hint or just a normal hint, use the cached allocation
-    // order from RegisterClassInfo.
-    ArrayRef<MCPhysReg> O = RCI.getOrder(RC);
-    Begin = O.begin();
-    End = O.end();
+  DEBUG({
+    if (!Hints.empty()) {
+      dbgs() << "hints:";
+      for (unsigned I = 0, E = Hints.size(); I != E; ++I)
+        dbgs() << ' ' << PrintReg(Hints[I], TRI);
+      dbgs() << '\n';
+    }
+  });
 }
 
-  // The hint must be a valid physreg for allocation.
-  if (Hint && (!TargetRegisterInfo::isPhysicalRegister(Hint) ||
-               !RC->contains(Hint) || MRI.isReserved(Hint)))
-    Hint = 0;
+bool AllocationOrder::isHint(unsigned PhysReg) const {
+  return std::find(Hints.begin(), Hints.end(), PhysReg) != Hints.end();
 }
 
-AllocationOrder::~AllocationOrder() {
-  if (OwnedBegin)
-    delete [] Begin;
+unsigned AllocationOrder::next() {
+  if (Pos < Hints.size())
+    return Hints[Pos++];
+  ArrayRef<MCPhysReg>::iterator I = Order.begin() + (Pos - Hints.size());
+  ArrayRef<MCPhysReg>::iterator E = Order.end();
+  while (I != E) {
+    unsigned Reg = *I++;
+    ++Pos;
+    if (!isHint(Reg))
+      return Reg;
+  }
+  return 0;
 }

lib/CodeGen/AllocationOrder.h

@@ -18,6 +18,7 @@
 #define LLVM_CODEGEN_ALLOCATIONORDER_H
 
 #include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/ADT/ArrayRef.h"
 
 namespace llvm {
 
@@ -25,15 +26,12 @@ class RegisterClassInfo;
 class VirtRegMap;
 
 class AllocationOrder {
-  const MCPhysReg *Begin;
-  const MCPhysReg *End;
-  const MCPhysReg *Pos;
-  const RegisterClassInfo &RCI;
-  unsigned Hint;
-  bool OwnedBegin;
-public:
+  SmallVector<MCPhysReg, 16> Hints;
+  ArrayRef<MCPhysReg> Order;
+  unsigned Pos;
 
-  /// AllocationOrder - Create a new AllocationOrder for VirtReg.
+public:
+  /// Create a new AllocationOrder for VirtReg.
   /// @param VirtReg      Virtual register to allocate for.
   /// @param VRM          Virtual register map for function.
   /// @param RegClassInfo Information about reserved and allocatable registers.
@@ -41,32 +39,19 @@ public:
                   const VirtRegMap &VRM,
                   const RegisterClassInfo &RegClassInfo);
 
-  ~AllocationOrder();
+  /// Return the next physical register in the allocation order, or 0.
+  /// It is safe to call next() again after it returned 0, it will keep
+  /// returning 0 until rewind() is called.
+  unsigned next();
 
-  /// next - Return the next physical register in the allocation order, or 0.
-  /// It is safe to call next again after it returned 0.
-  /// It will keep returning 0 until rewind() is called.
-  unsigned next() {
-    // First take the hint.
-    if (!Pos) {
-      Pos = Begin;
-      if (Hint)
-        return Hint;
-    }
-    // Then look at the order from TRI.
-    while (Pos != End) {
-      unsigned Reg = *Pos++;
-      if (Reg != Hint)
-        return Reg;
-    }
-    return 0;
-  }
-
-  /// rewind - Start over from the beginning.
+  /// Start over from the beginning.
   void rewind() { Pos = 0; }
 
-  /// isHint - Return true if PhysReg is a preferred register.
-  bool isHint(unsigned PhysReg) const { return PhysReg == Hint; }
+  /// Return true if the last register returned from next() was a preferred register.
+  bool isHint() const { return Pos <= Hints.size(); }
+
+  /// Return true if PhysReg is a preferred register.
+  bool isHint(unsigned PhysReg) const;
 };
 
 } // end namespace llvm