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llvm-mirror/tools/llvm-mca/Support.h
Andrea Di Biagio cf05a35161 [llvm-mca] Move the routine that computes processor resource masks to its own file.
Function computeProcResourceMasks is used by the ResourceManager (owned by the
Scheduler) to compute resource masks for processor resources.  Before this
refactoring, there was an implicit dependency between the Scheduler and the
InstrBuilder. That is because InstrBuilder has to know about resource masks when
computing the set of processor resources consumed by a new instruction.

With this patch, the functionality that computes resource masks has been
extracted from the ResourceManager, and moved to a separate file (Support.h). 
This helps removing the dependency between the Scheduler and the InstrBuilder.

No functional change intended.

llvm-svn: 327973
2018-03-20 12:25:54 +00:00

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1.8 KiB
C++

//===--------------------- 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