Pull PhysRegTracker out of RegAllocLinearScan as it can be used by other allocators as well
llvm-svn: 11720
diff --git a/llvm/lib/CodeGen/PhysRegTracker.h b/llvm/lib/CodeGen/PhysRegTracker.h
new file mode 100644
index 0000000..36128c6
--- /dev/null
+++ b/llvm/lib/CodeGen/PhysRegTracker.h
@@ -0,0 +1,79 @@
+//===-- llvm/CodeGen/LiveInterval.h - Live Interval Analysis ----*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a physical register tracker. The tracker
+// tracks physical register usage through addPhysRegUse and
+// delPhysRegUse functions while abstracting away register aliases.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_PHYSREGTRACKER_H
+#define LLVM_CODEGEN_PHYSREGTRACKER_H
+
+#include "llvm/CodeGen/MachineFunction.h"
+#include <vector>
+
+namespace llvm {
+
+ class PhysRegTracker {
+ private:
+ const MRegisterInfo* mri_;
+ std::vector<unsigned> regUse_;
+
+ public:
+ PhysRegTracker(MachineFunction* mf)
+ : mri_(mf ? mf->getTarget().getRegisterInfo() : NULL) {
+ if (mri_) {
+ regUse_.assign(mri_->getNumRegs(), 0);
+ }
+ }
+
+ PhysRegTracker(const PhysRegTracker& rhs)
+ : mri_(rhs.mri_),
+ regUse_(rhs.regUse_) {
+ }
+
+ const PhysRegTracker& operator=(const PhysRegTracker& rhs) {
+ mri_ = rhs.mri_;
+ regUse_ = rhs.regUse_;
+ return *this;
+ }
+
+ void addRegUse(unsigned physReg) {
+ assert(MRegisterInfo::isPhysicalRegister(physReg) &&
+ "should be physical register!");
+ ++regUse_[physReg];
+ for (const unsigned* as = mri_->getAliasSet(physReg); *as; ++as) {
+ physReg = *as;
+ ++regUse_[physReg];
+ }
+ }
+
+ void delRegUse(unsigned physReg) {
+ assert(MRegisterInfo::isPhysicalRegister(physReg) &&
+ "should be physical register!");
+ assert(regUse_[physReg] != 0);
+ --regUse_[physReg];
+ for (const unsigned* as = mri_->getAliasSet(physReg); *as; ++as) {
+ physReg = *as;
+ assert(regUse_[physReg] != 0);
+ --regUse_[physReg];
+ }
+ }
+
+ bool isPhysRegAvail(unsigned physReg) const {
+ assert(MRegisterInfo::isPhysicalRegister(physReg) &&
+ "should be physical register!");
+ return regUse_[physReg] == 0;
+ }
+ };
+
+} // End llvm namespace
+
+#endif