1 files changed, 109 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/RegAllocBase.h b/contrib/llvm/lib/CodeGen/RegAllocBase.h
new file mode 100644
index 000000000000..c17a8d96ef6a
--- /dev/null
+++ b/contrib/llvm/lib/CodeGen/RegAllocBase.h
@@ -0,0 +1,109 @@
+//===-- RegAllocBase.h - basic regalloc interface and driver --*- C++ -*---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the RegAllocBase class, which is the skeleton of a basic
+// register allocation algorithm and interface for extending it. It provides the
+// building blocks on which to construct other experimental allocators and test
+// the validity of two principles:
+//
+// - If virtual and physical register liveness is modeled using intervals, then
+// on-the-fly interference checking is cheap. Furthermore, interferences can be
+// lazily cached and reused.
+//
+// - Register allocation complexity, and generated code performance is
+// determined by the effectiveness of live range splitting rather than optimal
+// coloring.
+//
+// Following the first principle, interfering checking revolves around the
+// LiveIntervalUnion data structure.
+//
+// To fulfill the second principle, the basic allocator provides a driver for
+// incremental splitting. It essentially punts on the problem of register
+// coloring, instead driving the assignment of virtual to physical registers by
+// the cost of splitting. The basic allocator allows for heuristic reassignment
+// of registers, if a more sophisticated allocator chooses to do that.
+//
+// This framework provides a way to engineer the compile time vs. code
+// quality trade-off without relying on a particular theoretical solver.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_REGALLOCBASE
+#define LLVM_CODEGEN_REGALLOCBASE
+
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/CodeGen/LiveInterval.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
+
+namespace llvm {
+
+template<typename T> class SmallVectorImpl;
+class TargetRegisterInfo;
+class VirtRegMap;
+class LiveIntervals;
+class LiveRegMatrix;
+class Spiller;
+
+/// RegAllocBase provides the register allocation driver and interface that can
+/// be extended to add interesting heuristics.
+///
+/// Register allocators must override the selectOrSplit() method to implement
+/// live range splitting. They must also override enqueue/dequeue to provide an
+/// assignment order.
+class RegAllocBase {
+  virtual void anchor();
+protected:
+  const TargetRegisterInfo *TRI;
+  MachineRegisterInfo *MRI;
+  VirtRegMap *VRM;
+  LiveIntervals *LIS;
+  LiveRegMatrix *Matrix;
+  RegisterClassInfo RegClassInfo;
+
+  RegAllocBase(): TRI(0), MRI(0), VRM(0), LIS(0), Matrix(0) {}
+
+  virtual ~RegAllocBase() {}
+
+  // A RegAlloc pass should call this before allocatePhysRegs.
+  void init(VirtRegMap &vrm, LiveIntervals &lis, LiveRegMatrix &mat);
+
+  // The top-level driver. The output is a VirtRegMap that us updated with
+  // physical register assignments.
+  void allocatePhysRegs();
+
+  // Get a temporary reference to a Spiller instance.
+  virtual Spiller &spiller() = 0;
+
+  /// enqueue - Add VirtReg to the priority queue of unassigned registers.
+  virtual void enqueue(LiveInterval *LI) = 0;
+
+  /// dequeue - Return the next unassigned register, or NULL.
+  virtual LiveInterval *dequeue() = 0;
+
+  // A RegAlloc pass should override this to provide the allocation heuristics.
+  // Each call must guarantee forward progess by returning an available PhysReg
+  // or new set of split live virtual registers. It is up to the splitter to
+  // converge quickly toward fully spilled live ranges.
+  virtual unsigned selectOrSplit(LiveInterval &VirtReg,
+                                 SmallVectorImpl<unsigned> &splitLVRs) = 0;
+
+  // Use this group name for NamedRegionTimer.
+  static const char TimerGroupName[];
+
+public:
+  /// VerifyEnabled - True when -verify-regalloc is given.
+  static bool VerifyEnabled;
+
+private:
+  void seedLiveRegs();
+};
+
+} // end namespace llvm
+
+#endif // !defined(LLVM_CODEGEN_REGALLOCBASE)