1//===- MLRegAllocEvictAdvisor.cpp - ML eviction advisor -------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Function declarations of utilities related to feature extraction for unit
10// testing.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CODEGEN_MLREGALLOCEVICTIONADVISOR_H
15#define LLVM_CODEGEN_MLREGALLOCEVICTIONADVISOR_H
16
17#include "llvm/Analysis/MLModelRunner.h"
18#include "llvm/CodeGen/MachineBasicBlock.h"
19#include "llvm/CodeGen/SlotIndexes.h"
20#include "llvm/Support/Compiler.h"
21#include <map>
22
23namespace llvm {
24
25// LRStartEndInfo contains the start and end of a specific live range as
26// slot indices as well as storing the index of the physical register it
27// is assigned to (or 1 above the phys reg count if its the candidate).
28// Used when extracting per-instruction features in the context of a
29// specific eviction problem.
30struct LRStartEndInfo {
31 SlotIndex Begin;
32 SlotIndex End;
33 size_t Pos = 0;
34};
35
36// The number of instructions that a specific live range might have is variable,
37// but we're passing in a single matrix of instructions and tensorflow saved
38// models only support a fixed input size, so we have to cap the number of
39// instructions that can be passed along. The specific value was derived from
40// experimentation such that the majority of eviction problems would be
41// completely covered.
42static const int ModelMaxSupportedInstructionCount = 300;
43
44// When extracting per-instruction features, the advisor will currently create
45// a vector of size ModelMaxSupportedInstructionCount to hold the opcodes of the
46// instructions relevant to the eviction problem.
47static const std::vector<int64_t> InstructionsShape{
48 1, ModelMaxSupportedInstructionCount};
49
50// When extracting mappings between MBBs and individual instructions, we create
51// a vector of MBB frequencies, currently of size 100, which was a value
52// determined through experimentation to encompass the vast majority of eviction
53// problems. The actual mapping is the same shape as the instruction opcodes
54// vector.
55static const int64_t ModelMaxSupportedMBBCount = 100;
56static const std::vector<int64_t> MBBFrequencyShape{1,
57 ModelMaxSupportedMBBCount};
58
59} // namespace llvm
60
61#endif // LLVM_CODEGEN_MLREGALLOCEVICTIONADVISOR_H
62