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diff --git a/llvm/tools/llvm-mca/Support.h b/llvm/tools/llvm-mca/Support.h
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+//===--------------------- Support.h ----------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// Helper functions used by various backend components.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_MCA_SUPPORT_H
+#define LLVM_TOOLS_LLVM_MCA_SUPPORT_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/MC/MCSchedule.h"
+
+namespace mca {
+
+/// Populates vector Masks with processor resource masks.
+///
+/// The number of bits set in a mask depends on the processor resource type.
+/// Each processor resource mask has at least one bit set. For groups, the
+/// number of bits set in the mask is equal to the cardinality of the group plus
+/// one. Excluding the most significant bit, the remaining bits in the mask
+/// identify processor resources that are part of the group.
+///
+/// Example:
+///
+///  ResourceA  -- Mask: 0b001
+///  ResourceB  -- Mask: 0b010
+///  ResourceAB -- Mask: 0b100 U (ResourceA::Mask | ResourceB::Mask) == 0b111
+///
+/// ResourceAB is a processor resource group containing ResourceA and ResourceB.
+/// Each resource mask uniquely identifies a resource; both ResourceA and
+/// ResourceB only have one bit set.
+/// ResourceAB is a group; excluding the most significant bit in the mask, the
+/// remaining bits identify the composition of the group.
+///
+/// Resource masks are used by the ResourceManager to solve set membership
+/// problems with simple bit manipulation operations.
+void computeProcResourceMasks(const llvm::MCSchedModel &SM,
+                              llvm::SmallVectorImpl<uint64_t> &Masks);
+} // namespace mca
+
+#endif