1//===--------------------- InstructionTables.cpp ----------------*- C++ -*-===//
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/// \file
9///
10/// This file implements the method InstructionTables::execute().
11/// Method execute() prints a theoretical resource pressure distribution based
12/// on the information available in the scheduling model, and without running
13/// the pipeline.
14///
15//===----------------------------------------------------------------------===//
16
17#include "llvm/MCA/Stages/InstructionTables.h"
18
19namespace llvm {
20namespace mca {
21
22Error InstructionTables::execute(InstRef &IR) {
23 const InstrDesc &Desc = IR.getInstruction()->getDesc();
24 UsedResources.clear();
25
26 // Identify the resources consumed by this instruction.
27 for (const std::pair<uint64_t, ResourceUsage> &Resource :
28 Desc.Resources) {
29 // Skip zero-cycle resources (i.e., unused resources).
30 if (!Resource.second.size())
31 continue;
32 unsigned Cycles = Resource.second.size();
33 unsigned Index = std::distance(first: Masks.begin(), last: find(Range&: Masks, Val: Resource.first));
34 const MCProcResourceDesc &ProcResource = *SM.getProcResource(ProcResourceIdx: Index);
35 unsigned NumUnits = ProcResource.NumUnits;
36 if (!ProcResource.SubUnitsIdxBegin) {
37 // The number of cycles consumed by each unit.
38 for (unsigned I = 0, E = NumUnits; I < E; ++I) {
39 ResourceRef ResourceUnit = std::make_pair(x&: Index, y: 1U << I);
40 UsedResources.emplace_back(
41 Args: std::make_pair(x&: ResourceUnit, y: ReleaseAtCycles(Cycles, NumUnits)));
42 }
43 continue;
44 }
45
46 // This is a group. Obtain the set of resources contained in this
47 // group. Some of these resources may implement multiple units.
48 // Uniformly distribute Cycles across all of the units.
49 for (unsigned I1 = 0; I1 < NumUnits; ++I1) {
50 unsigned SubUnitIdx = ProcResource.SubUnitsIdxBegin[I1];
51 const MCProcResourceDesc &SubUnit = *SM.getProcResource(ProcResourceIdx: SubUnitIdx);
52 // Compute the number of cycles consumed by each resource unit.
53 for (unsigned I2 = 0, E2 = SubUnit.NumUnits; I2 < E2; ++I2) {
54 ResourceRef ResourceUnit = std::make_pair(x&: SubUnitIdx, y: 1U << I2);
55 UsedResources.emplace_back(Args: std::make_pair(
56 x&: ResourceUnit,
57 y: ReleaseAtCycles(Cycles, NumUnits * SubUnit.NumUnits)));
58 }
59 }
60 }
61
62 // Send a fake instruction issued event to all the views.
63 HWInstructionIssuedEvent Event(IR, UsedResources);
64 notifyEvent<HWInstructionIssuedEvent>(Event);
65 return ErrorSuccess();
66}
67
68} // namespace mca
69} // namespace llvm
70