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diff --git a/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h b/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h
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+++ b/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h
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+//===- llvm/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DBGVALUEHISTORYCALCULATOR_H
+#define LLVM_LIB_CODEGEN_ASMPRINTER_DBGVALUEHISTORYCALCULATOR_H
+
+#include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+#include <utility>
+
+namespace llvm {
+
+class DILocalVariable;
+class MachineFunction;
+class MachineInstr;
+class TargetRegisterInfo;
+
+// For each user variable, keep a list of instruction ranges where this variable
+// is accessible. The variables are listed in order of appearance.
+class DbgValueHistoryMap {
+  // Each instruction range starts with a DBG_VALUE instruction, specifying the
+  // location of a variable, which is assumed to be valid until the end of the
+  // range. If end is not specified, location is valid until the start
+  // instruction of the next instruction range, or until the end of the
+  // function.
+public:
+  using InstrRange = std::pair<const MachineInstr *, const MachineInstr *>;
+  using InstrRanges = SmallVector<InstrRange, 4>;
+  using InlinedVariable =
+      std::pair<const DILocalVariable *, const DILocation *>;
+  using InstrRangesMap = MapVector<InlinedVariable, InstrRanges>;
+
+private:
+  InstrRangesMap VarInstrRanges;
+
+public:
+  void startInstrRange(InlinedVariable Var, const MachineInstr &MI);
+  void endInstrRange(InlinedVariable Var, const MachineInstr &MI);
+
+  // Returns register currently describing @Var. If @Var is currently
+  // unaccessible or is not described by a register, returns 0.
+  unsigned getRegisterForVar(InlinedVariable Var) const;
+
+  bool empty() const { return VarInstrRanges.empty(); }
+  void clear() { VarInstrRanges.clear(); }
+  InstrRangesMap::const_iterator begin() const { return VarInstrRanges.begin(); }
+  InstrRangesMap::const_iterator end() const { return VarInstrRanges.end(); }
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  LLVM_DUMP_METHOD void dump() const;
+#endif
+};
+
+void calculateDbgValueHistory(const MachineFunction *MF,
+                              const TargetRegisterInfo *TRI,
+                              DbgValueHistoryMap &Result);
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_CODEGEN_ASMPRINTER_DBGVALUEHISTORYCALCULATOR_H