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llvm-mirror/utils/TableGen/SubtargetEmitter.cpp

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//===- SubtargetEmitter.cpp - Generate subtarget enumerations -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend emits subtarget enumerations.
//
//===----------------------------------------------------------------------===//
#include "CodeGenTarget.h"
#include "CodeGenSchedule.h"
#include "PredicateExpander.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/MC/MCSchedule.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <map>
#include <string>
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "subtarget-emitter"
namespace {
class SubtargetEmitter {
// Each processor has a SchedClassDesc table with an entry for each SchedClass.
// The SchedClassDesc table indexes into a global write resource table, write
// latency table, and read advance table.
struct SchedClassTables {
std::vector<std::vector<MCSchedClassDesc>> ProcSchedClasses;
std::vector<MCWriteProcResEntry> WriteProcResources;
std::vector<MCWriteLatencyEntry> WriteLatencies;
std::vector<std::string> WriterNames;
std::vector<MCReadAdvanceEntry> ReadAdvanceEntries;
// Reserve an invalid entry at index 0
SchedClassTables() {
ProcSchedClasses.resize(1);
WriteProcResources.resize(1);
WriteLatencies.resize(1);
WriterNames.push_back("InvalidWrite");
ReadAdvanceEntries.resize(1);
}
};
struct LessWriteProcResources {
bool operator()(const MCWriteProcResEntry &LHS,
const MCWriteProcResEntry &RHS) {
return LHS.ProcResourceIdx < RHS.ProcResourceIdx;
}
};
const CodeGenTarget &TGT;
RecordKeeper &Records;
CodeGenSchedModels &SchedModels;
std::string Target;
void Enumeration(raw_ostream &OS, DenseMap<Record *, unsigned> &FeatureMap);
unsigned FeatureKeyValues(raw_ostream &OS,
const DenseMap<Record *, unsigned> &FeatureMap);
unsigned CPUKeyValues(raw_ostream &OS,
const DenseMap<Record *, unsigned> &FeatureMap);
void FormItineraryStageString(const std::string &Names,
Record *ItinData, std::string &ItinString,
unsigned &NStages);
void FormItineraryOperandCycleString(Record *ItinData, std::string &ItinString,
unsigned &NOperandCycles);
void FormItineraryBypassString(const std::string &Names,
Record *ItinData,
std::string &ItinString, unsigned NOperandCycles);
void EmitStageAndOperandCycleData(raw_ostream &OS,
std::vector<std::vector<InstrItinerary>>
&ProcItinLists);
void EmitItineraries(raw_ostream &OS,
std::vector<std::vector<InstrItinerary>>
&ProcItinLists);
unsigned EmitRegisterFileTables(const CodeGenProcModel &ProcModel,
raw_ostream &OS);
[llvm-mca][MC] Add the ability to declare which processor resources model load/store queues (PR36666). This patch adds the ability to specify via tablegen which processor resources are load/store queue resources. A new tablegen class named MemoryQueue can be optionally used to mark resources that model load/store queues. Information about the load/store queue is collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and `StoreQueueID`. Those two fields are identifiers for buffered resources used to describe the load queue and the store queue. Field `BufferSize` is interpreted as the number of entries in the queue, while the number of units is a throughput indicator (i.e. number of available pickers for loads/stores). At construction time, LSUnit in llvm-mca checks for the presence of extra processor information (i.e. MCExtraProcessorInfo) in the scheduling model. If that information is available, and fields LoadQueueID and StoreQueueID are set to a value different than zero (i.e. the invalid processor resource index), then LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value declared by the two processor resources. With this patch, we more accurately track dynamic dispatch stalls caused by the lack of LS tokens (i.e. load/store queue full). This is also shown by the differences in two BdVer2 tests. Stalls that were previously classified as generic SCHEDULER FULL stalls, are not correctly classified either as "load queue full" or "store queue full". About the differences in the -scheduler-stats view: those differences are expected, because entries in the load/store queue are not released at instruction issue stage. Instead, those are released at instruction executed stage. This is the main reason why for the modified tests, the load/store queues gets full before PdEx is full. Differential Revision: https://reviews.llvm.org/D54957 llvm-svn: 347857
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void EmitLoadStoreQueueInfo(const CodeGenProcModel &ProcModel,
raw_ostream &OS);
void EmitExtraProcessorInfo(const CodeGenProcModel &ProcModel,
raw_ostream &OS);
void EmitProcessorProp(raw_ostream &OS, const Record *R, StringRef Name,
char Separator);
void EmitProcessorResourceSubUnits(const CodeGenProcModel &ProcModel,
raw_ostream &OS);
void EmitProcessorResources(const CodeGenProcModel &ProcModel,
raw_ostream &OS);
Record *FindWriteResources(const CodeGenSchedRW &SchedWrite,
const CodeGenProcModel &ProcModel);
Record *FindReadAdvance(const CodeGenSchedRW &SchedRead,
const CodeGenProcModel &ProcModel);
void ExpandProcResources(RecVec &PRVec, std::vector<int64_t> &Cycles,
const CodeGenProcModel &ProcModel);
void GenSchedClassTables(const CodeGenProcModel &ProcModel,
SchedClassTables &SchedTables);
void EmitSchedClassTables(SchedClassTables &SchedTables, raw_ostream &OS);
void EmitProcessorModels(raw_ostream &OS);
void EmitSchedModelHelpers(const std::string &ClassName, raw_ostream &OS);
void emitSchedModelHelpersImpl(raw_ostream &OS,
bool OnlyExpandMCInstPredicates = false);
void emitGenMCSubtargetInfo(raw_ostream &OS);
[TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions. This patch adds the ability for processor models to describe dependency breaking instructions. Different processors may specify a different set of dependency-breaking instructions. That means, we cannot assume that all processors of the same target would use the same rules to classify dependency breaking instructions. The main goal of this patch is to provide the means to describe dependency breaking instructions directly via tablegen, and have the following TargetSubtargetInfo hooks redefined in overrides by tabegen'd XXXGenSubtargetInfo classes (here, XXX is a Target name). ``` virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const { return false; } virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const { return isZeroIdiom(MI); } ``` An instruction MI is a dependency-breaking instruction if a call to method isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to true. Similarly, an instruction MI is a special case of zero-idiom dependency breaking instruction if a call to STI.isZeroIdiom(MI) returns true. The extra APInt is used for those targets that may want to select which machine operands have their dependency broken (see comments in code). Note that by default, subtargets don't know about the existence of dependency-breaking. In the absence of external information, those method calls would always return false. A new tablegen class named STIPredicate has been added by this patch to let processor models classify instructions that have properties in common. The idea is that, a MCInstrPredicate definition can be used to "generate" an instruction equivalence class, with the idea that instructions of a same class all have a property in common. STIPredicate definitions are essentially a collection of instruction equivalence classes. Also, different processor models can specify a different variant of the same STIPredicate with different rules (i.e. predicates) to classify instructions. Tablegen backends (in this particular case, the SubtargetEmitter) will be able to process STIPredicate definitions, and automatically generate functions in XXXGenSubtargetInfo. This patch introduces two special kind of STIPredicate classes named IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a definition for those in the BtVer2 scheduling model only. This patch supersedes the one committed at r338372 (phabricator review: D49310). The main advantages are: - We can describe subtarget predicates via tablegen using STIPredicates. - We can describe zero-idioms / dep-breaking instructions directly via tablegen in the scheduling models. In future, the STIPredicates framework can be used for solving other problems. Examples of future developments are: - Teach how to identify optimizable register-register moves - Teach how to identify slow LEA instructions (each subtarget defining its own concept of "slow" LEA). - Teach how to identify instructions that have undocumented false dependencies on the output registers on some processors only. It is also (in my opinion) an elegant way to expose knowledge to both external tools like llvm-mca, and codegen passes. For example, machine schedulers in LLVM could reuse that information when internally constructing the data dependency graph for a code region. This new design feature is also an "opt-in" feature. Processor models don't have to use the new STIPredicates. It has all been designed to be as unintrusive as possible. Differential Revision: https://reviews.llvm.org/D52174 llvm-svn: 342555
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void EmitMCInstrAnalysisPredicateFunctions(raw_ostream &OS);
void EmitSchedModel(raw_ostream &OS);
void EmitHwModeCheck(const std::string &ClassName, raw_ostream &OS);
void ParseFeaturesFunction(raw_ostream &OS, unsigned NumFeatures,
unsigned NumProcs);
public:
SubtargetEmitter(RecordKeeper &R, CodeGenTarget &TGT)
: TGT(TGT), Records(R), SchedModels(TGT.getSchedModels()),
Target(TGT.getName()) {}
void run(raw_ostream &o);
};
} // end anonymous namespace
//
// Enumeration - Emit the specified class as an enumeration.
//
void SubtargetEmitter::Enumeration(raw_ostream &OS,
DenseMap<Record *, unsigned> &FeatureMap) {
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// Get all records of class and sort
std::vector<Record*> DefList =
Records.getAllDerivedDefinitions("SubtargetFeature");
llvm::sort(DefList, LessRecord());
unsigned N = DefList.size();
if (N == 0)
return;
if (N + 1 > MAX_SUBTARGET_FEATURES)
PrintFatalError("Too many subtarget features! Bump MAX_SUBTARGET_FEATURES.");
OS << "namespace " << Target << " {\n";
// Open enumeration.
OS << "enum {\n";
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// For each record
for (unsigned i = 0; i < N; ++i) {
// Next record
Record *Def = DefList[i];
// Get and emit name
OS << " " << Def->getName() << " = " << i << ",\n";
// Save the index for this feature.
FeatureMap[Def] = i;
}
OS << " "
<< "NumSubtargetFeatures = " << N << "\n";
// Close enumeration and namespace
OS << "};\n";
OS << "} // end namespace " << Target << "\n";
}
static void printFeatureMask(raw_ostream &OS, RecVec &FeatureList,
const DenseMap<Record *, unsigned> &FeatureMap) {
std::array<uint64_t, MAX_SUBTARGET_WORDS> Mask = {};
for (const Record *Feature : FeatureList) {
unsigned Bit = FeatureMap.lookup(Feature);
Mask[Bit / 64] |= 1ULL << (Bit % 64);
}
OS << "{ { { ";
for (unsigned i = 0; i != Mask.size(); ++i) {
OS << "0x";
OS.write_hex(Mask[i]);
OS << "ULL, ";
}
OS << "} } }";
}
//
// FeatureKeyValues - Emit data of all the subtarget features. Used by the
// command line.
//
unsigned SubtargetEmitter::FeatureKeyValues(
raw_ostream &OS, const DenseMap<Record *, unsigned> &FeatureMap) {
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// Gather and sort all the features
std::vector<Record*> FeatureList =
Records.getAllDerivedDefinitions("SubtargetFeature");
if (FeatureList.empty())
return 0;
llvm::sort(FeatureList, LessRecordFieldName());
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// Begin feature table
OS << "// Sorted (by key) array of values for CPU features.\n"
<< "extern const llvm::SubtargetFeatureKV " << Target
<< "FeatureKV[] = {\n";
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// For each feature
unsigned NumFeatures = 0;
for (const Record *Feature : FeatureList) {
// Next feature
StringRef Name = Feature->getName();
StringRef CommandLineName = Feature->getValueAsString("Name");
StringRef Desc = Feature->getValueAsString("Desc");
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if (CommandLineName.empty()) continue;
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// Emit as { "feature", "description", { featureEnum }, { i1 , i2 , ... , in } }
OS << " { "
<< "\"" << CommandLineName << "\", "
<< "\"" << Desc << "\", "
<< Target << "::" << Name << ", ";
RecVec ImpliesList = Feature->getValueAsListOfDefs("Implies");
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printFeatureMask(OS, ImpliesList, FeatureMap);
OS << " },\n";
++NumFeatures;
}
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// End feature table
OS << "};\n";
return NumFeatures;
}
//
// CPUKeyValues - Emit data of all the subtarget processors. Used by command
// line.
//
unsigned
SubtargetEmitter::CPUKeyValues(raw_ostream &OS,
const DenseMap<Record *, unsigned> &FeatureMap) {
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// Gather and sort processor information
std::vector<Record*> ProcessorList =
Records.getAllDerivedDefinitions("Processor");
llvm::sort(ProcessorList, LessRecordFieldName());
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// Begin processor table
OS << "// Sorted (by key) array of values for CPU subtype.\n"
<< "extern const llvm::SubtargetSubTypeKV " << Target
<< "SubTypeKV[] = {\n";
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// For each processor
for (Record *Processor : ProcessorList) {
StringRef Name = Processor->getValueAsString("Name");
RecVec FeatureList = Processor->getValueAsListOfDefs("Features");
RecVec TuneFeatureList = Processor->getValueAsListOfDefs("TuneFeatures");
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// Emit as { "cpu", "description", 0, { f1 , f2 , ... fn } },
OS << " { "
<< "\"" << Name << "\", ";
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printFeatureMask(OS, FeatureList, FeatureMap);
OS << ", ";
printFeatureMask(OS, TuneFeatureList, FeatureMap);
// Emit the scheduler model pointer.
const std::string &ProcModelName =
SchedModels.getModelForProc(Processor).ModelName;
OS << ", &" << ProcModelName << " },\n";
}
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// End processor table
OS << "};\n";
return ProcessorList.size();
}
//
// FormItineraryStageString - Compose a string containing the stage
// data initialization for the specified itinerary. N is the number
// of stages.
//
void SubtargetEmitter::FormItineraryStageString(const std::string &Name,
Record *ItinData,
std::string &ItinString,
unsigned &NStages) {
// Get states list
RecVec StageList = ItinData->getValueAsListOfDefs("Stages");
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// For each stage
unsigned N = NStages = StageList.size();
for (unsigned i = 0; i < N;) {
// Next stage
const Record *Stage = StageList[i];
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// Form string as ,{ cycles, u1 | u2 | ... | un, timeinc, kind }
int Cycles = Stage->getValueAsInt("Cycles");
ItinString += " { " + itostr(Cycles) + ", ";
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// Get unit list
RecVec UnitList = Stage->getValueAsListOfDefs("Units");
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// For each unit
for (unsigned j = 0, M = UnitList.size(); j < M;) {
// Add name and bitwise or
ItinString += Name + "FU::" + UnitList[j]->getName().str();
if (++j < M) ItinString += " | ";
}
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int TimeInc = Stage->getValueAsInt("TimeInc");
ItinString += ", " + itostr(TimeInc);
int Kind = Stage->getValueAsInt("Kind");
ItinString += ", (llvm::InstrStage::ReservationKinds)" + itostr(Kind);
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// Close off stage
ItinString += " }";
if (++i < N) ItinString += ", ";
}
}
//
// FormItineraryOperandCycleString - Compose a string containing the
// operand cycle initialization for the specified itinerary. N is the
// number of operands that has cycles specified.
//
void SubtargetEmitter::FormItineraryOperandCycleString(Record *ItinData,
std::string &ItinString, unsigned &NOperandCycles) {
// Get operand cycle list
std::vector<int64_t> OperandCycleList =
ItinData->getValueAsListOfInts("OperandCycles");
// For each operand cycle
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NOperandCycles = OperandCycleList.size();
ListSeparator LS;
for (int OCycle : OperandCycleList) {
// Next operand cycle
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ItinString += LS;
ItinString += " " + itostr(OCycle);
}
}
void SubtargetEmitter::FormItineraryBypassString(const std::string &Name,
Record *ItinData,
std::string &ItinString,
unsigned NOperandCycles) {
RecVec BypassList = ItinData->getValueAsListOfDefs("Bypasses");
unsigned N = BypassList.size();
unsigned i = 0;
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ListSeparator LS;
for (; i < N; ++i) {
ItinString += LS;
ItinString += Name + "Bypass::" + BypassList[i]->getName().str();
}
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for (; i < NOperandCycles; ++i) {
ItinString += LS;
ItinString += " 0";
}
}
//
// EmitStageAndOperandCycleData - Generate unique itinerary stages and operand
// cycle tables. Create a list of InstrItinerary objects (ProcItinLists) indexed
// by CodeGenSchedClass::Index.
//
void SubtargetEmitter::
EmitStageAndOperandCycleData(raw_ostream &OS,
std::vector<std::vector<InstrItinerary>>
&ProcItinLists) {
// Multiple processor models may share an itinerary record. Emit it once.
SmallPtrSet<Record*, 8> ItinsDefSet;
// Emit functional units for all the itineraries.
for (const CodeGenProcModel &ProcModel : SchedModels.procModels()) {
if (!ItinsDefSet.insert(ProcModel.ItinsDef).second)
continue;
RecVec FUs = ProcModel.ItinsDef->getValueAsListOfDefs("FU");
if (FUs.empty())
continue;
StringRef Name = ProcModel.ItinsDef->getName();
OS << "\n// Functional units for \"" << Name << "\"\n"
<< "namespace " << Name << "FU {\n";
for (unsigned j = 0, FUN = FUs.size(); j < FUN; ++j)
OS << " const InstrStage::FuncUnits " << FUs[j]->getName()
<< " = 1ULL << " << j << ";\n";
OS << "} // end namespace " << Name << "FU\n";
RecVec BPs = ProcModel.ItinsDef->getValueAsListOfDefs("BP");
if (!BPs.empty()) {
OS << "\n// Pipeline forwarding paths for itineraries \"" << Name
<< "\"\n" << "namespace " << Name << "Bypass {\n";
OS << " const unsigned NoBypass = 0;\n";
for (unsigned j = 0, BPN = BPs.size(); j < BPN; ++j)
OS << " const unsigned " << BPs[j]->getName()
<< " = 1 << " << j << ";\n";
OS << "} // end namespace " << Name << "Bypass\n";
}
}
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// Begin stages table
std::string StageTable = "\nextern const llvm::InstrStage " + Target +
"Stages[] = {\n";
StageTable += " { 0, 0, 0, llvm::InstrStage::Required }, // No itinerary\n";
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// Begin operand cycle table
std::string OperandCycleTable = "extern const unsigned " + Target +
"OperandCycles[] = {\n";
OperandCycleTable += " 0, // No itinerary\n";
// Begin pipeline bypass table
std::string BypassTable = "extern const unsigned " + Target +
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"ForwardingPaths[] = {\n";
BypassTable += " 0, // No itinerary\n";
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// For each Itinerary across all processors, add a unique entry to the stages,
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// operand cycles, and pipeline bypass tables. Then add the new Itinerary
// object with computed offsets to the ProcItinLists result.
unsigned StageCount = 1, OperandCycleCount = 1;
std::map<std::string, unsigned> ItinStageMap, ItinOperandMap;
for (const CodeGenProcModel &ProcModel : SchedModels.procModels()) {
// Add process itinerary to the list.
ProcItinLists.resize(ProcItinLists.size()+1);
// If this processor defines no itineraries, then leave the itinerary list
// empty.
std::vector<InstrItinerary> &ItinList = ProcItinLists.back();
if (!ProcModel.hasItineraries())
continue;
StringRef Name = ProcModel.ItinsDef->getName();
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ItinList.resize(SchedModels.numInstrSchedClasses());
assert(ProcModel.ItinDefList.size() == ItinList.size() && "bad Itins");
for (unsigned SchedClassIdx = 0, SchedClassEnd = ItinList.size();
SchedClassIdx < SchedClassEnd; ++SchedClassIdx) {
// Next itinerary data
Record *ItinData = ProcModel.ItinDefList[SchedClassIdx];
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// Get string and stage count
std::string ItinStageString;
unsigned NStages = 0;
if (ItinData)
FormItineraryStageString(std::string(Name), ItinData, ItinStageString,
NStages);
// Get string and operand cycle count
std::string ItinOperandCycleString;
unsigned NOperandCycles = 0;
std::string ItinBypassString;
if (ItinData) {
FormItineraryOperandCycleString(ItinData, ItinOperandCycleString,
NOperandCycles);
FormItineraryBypassString(std::string(Name), ItinData, ItinBypassString,
NOperandCycles);
}
// Check to see if stage already exists and create if it doesn't
uint16_t FindStage = 0;
if (NStages > 0) {
FindStage = ItinStageMap[ItinStageString];
if (FindStage == 0) {
// Emit as { cycles, u1 | u2 | ... | un, timeinc }, // indices
StageTable += ItinStageString + ", // " + itostr(StageCount);
if (NStages > 1)
StageTable += "-" + itostr(StageCount + NStages - 1);
StageTable += "\n";
// Record Itin class number.
ItinStageMap[ItinStageString] = FindStage = StageCount;
StageCount += NStages;
}
}
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// Check to see if operand cycle already exists and create if it doesn't
uint16_t FindOperandCycle = 0;
if (NOperandCycles > 0) {
std::string ItinOperandString = ItinOperandCycleString+ItinBypassString;
FindOperandCycle = ItinOperandMap[ItinOperandString];
if (FindOperandCycle == 0) {
// Emit as cycle, // index
OperandCycleTable += ItinOperandCycleString + ", // ";
std::string OperandIdxComment = itostr(OperandCycleCount);
if (NOperandCycles > 1)
OperandIdxComment += "-"
+ itostr(OperandCycleCount + NOperandCycles - 1);
OperandCycleTable += OperandIdxComment + "\n";
// Record Itin class number.
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ItinOperandMap[ItinOperandCycleString] =
FindOperandCycle = OperandCycleCount;
// Emit as bypass, // index
BypassTable += ItinBypassString + ", // " + OperandIdxComment + "\n";
OperandCycleCount += NOperandCycles;
}
}
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// Set up itinerary as location and location + stage count
int16_t NumUOps = ItinData ? ItinData->getValueAsInt("NumMicroOps") : 0;
InstrItinerary Intinerary = {
NumUOps,
FindStage,
uint16_t(FindStage + NStages),
FindOperandCycle,
uint16_t(FindOperandCycle + NOperandCycles),
};
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// Inject - empty slots will be 0, 0
ItinList[SchedClassIdx] = Intinerary;
}
}
// Closing stage
StageTable += " { 0, 0, 0, llvm::InstrStage::Required } // End stages\n";
StageTable += "};\n";
// Closing operand cycles
OperandCycleTable += " 0 // End operand cycles\n";
OperandCycleTable += "};\n";
BypassTable += " 0 // End bypass tables\n";
BypassTable += "};\n";
// Emit tables.
OS << StageTable;
OS << OperandCycleTable;
OS << BypassTable;
}
//
// EmitProcessorData - Generate data for processor itineraries that were
// computed during EmitStageAndOperandCycleData(). ProcItinLists lists all
// Itineraries for each processor. The Itinerary lists are indexed on
// CodeGenSchedClass::Index.
//
void SubtargetEmitter::
EmitItineraries(raw_ostream &OS,
std::vector<std::vector<InstrItinerary>> &ProcItinLists) {
// Multiple processor models may share an itinerary record. Emit it once.
SmallPtrSet<Record*, 8> ItinsDefSet;
// For each processor's machine model
std::vector<std::vector<InstrItinerary>>::iterator
ProcItinListsIter = ProcItinLists.begin();
for (CodeGenSchedModels::ProcIter PI = SchedModels.procModelBegin(),
PE = SchedModels.procModelEnd(); PI != PE; ++PI, ++ProcItinListsIter) {
Record *ItinsDef = PI->ItinsDef;
if (!ItinsDefSet.insert(ItinsDef).second)
continue;
// Get the itinerary list for the processor.
assert(ProcItinListsIter != ProcItinLists.end() && "bad iterator");
std::vector<InstrItinerary> &ItinList = *ProcItinListsIter;
// Empty itineraries aren't referenced anywhere in the tablegen output
// so don't emit them.
if (ItinList.empty())
continue;
OS << "\n";
OS << "static const llvm::InstrItinerary ";
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// Begin processor itinerary table
OS << ItinsDef->getName() << "[] = {\n";
// For each itinerary class in CodeGenSchedClass::Index order.
for (unsigned j = 0, M = ItinList.size(); j < M; ++j) {
InstrItinerary &Intinerary = ItinList[j];
// Emit Itinerary in the form of
// { firstStage, lastStage, firstCycle, lastCycle } // index
OS << " { " <<
Intinerary.NumMicroOps << ", " <<
Intinerary.FirstStage << ", " <<
Intinerary.LastStage << ", " <<
Intinerary.FirstOperandCycle << ", " <<
Intinerary.LastOperandCycle << " }" <<
", // " << j << " " << SchedModels.getSchedClass(j).Name << "\n";
}
// End processor itinerary table
OS << " { 0, uint16_t(~0U), uint16_t(~0U), uint16_t(~0U), uint16_t(~0U) }"
"// end marker\n";
OS << "};\n";
}
}
// Emit either the value defined in the TableGen Record, or the default
// value defined in the C++ header. The Record is null if the processor does not
// define a model.
void SubtargetEmitter::EmitProcessorProp(raw_ostream &OS, const Record *R,
StringRef Name, char Separator) {
OS << " ";
int V = R ? R->getValueAsInt(Name) : -1;
if (V >= 0)
OS << V << Separator << " // " << Name;
else
OS << "MCSchedModel::Default" << Name << Separator;
OS << '\n';
}
void SubtargetEmitter::EmitProcessorResourceSubUnits(
const CodeGenProcModel &ProcModel, raw_ostream &OS) {
OS << "\nstatic const unsigned " << ProcModel.ModelName
<< "ProcResourceSubUnits[] = {\n"
<< " 0, // Invalid\n";
for (unsigned i = 0, e = ProcModel.ProcResourceDefs.size(); i < e; ++i) {
Record *PRDef = ProcModel.ProcResourceDefs[i];
if (!PRDef->isSubClassOf("ProcResGroup"))
continue;
RecVec ResUnits = PRDef->getValueAsListOfDefs("Resources");
for (Record *RUDef : ResUnits) {
Record *const RU =
SchedModels.findProcResUnits(RUDef, ProcModel, PRDef->getLoc());
for (unsigned J = 0; J < RU->getValueAsInt("NumUnits"); ++J) {
OS << " " << ProcModel.getProcResourceIdx(RU) << ", ";
}
}
OS << " // " << PRDef->getName() << "\n";
}
OS << "};\n";
}
static void EmitRetireControlUnitInfo(const CodeGenProcModel &ProcModel,
raw_ostream &OS) {
int64_t ReorderBufferSize = 0, MaxRetirePerCycle = 0;
if (Record *RCU = ProcModel.RetireControlUnit) {
ReorderBufferSize =
std::max(ReorderBufferSize, RCU->getValueAsInt("ReorderBufferSize"));
MaxRetirePerCycle =
std::max(MaxRetirePerCycle, RCU->getValueAsInt("MaxRetirePerCycle"));
}
OS << ReorderBufferSize << ", // ReorderBufferSize\n ";
OS << MaxRetirePerCycle << ", // MaxRetirePerCycle\n ";
}
static void EmitRegisterFileInfo(const CodeGenProcModel &ProcModel,
unsigned NumRegisterFiles,
unsigned NumCostEntries, raw_ostream &OS) {
if (NumRegisterFiles)
OS << ProcModel.ModelName << "RegisterFiles,\n " << (1 + NumRegisterFiles);
else
OS << "nullptr,\n 0";
OS << ", // Number of register files.\n ";
if (NumCostEntries)
OS << ProcModel.ModelName << "RegisterCosts,\n ";
else
OS << "nullptr,\n ";
OS << NumCostEntries << ", // Number of register cost entries.\n";
}
unsigned
SubtargetEmitter::EmitRegisterFileTables(const CodeGenProcModel &ProcModel,
raw_ostream &OS) {
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
if (llvm::all_of(ProcModel.RegisterFiles, [](const CodeGenRegisterFile &RF) {
return RF.hasDefaultCosts();
}))
return 0;
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
// Print the RegisterCost table first.
[tblgen][llvm-mca] Add the ability to describe move elimination candidates via tablegen. This patch adds the ability to identify instructions that are "move elimination candidates". It also allows scheduling models to describe processor register files that allow move elimination. A move elimination candidate is an instruction that can be eliminated at register renaming stage. Each subtarget can specify which instructions are move elimination candidates with the help of tablegen class "IsOptimizableRegisterMove" (see llvm/Target/TargetInstrPredicate.td). For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated. The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this: ``` def : IsOptimizableRegisterMove<[ InstructionEquivalenceClass<[ // GPR variants. MOV32rr, MOV64rr, // MMX variants. MMX_MOVQ64rr, // SSE variants. MOVAPSrr, MOVUPSrr, MOVAPDrr, MOVUPDrr, MOVDQArr, MOVDQUrr, // AVX variants. VMOVAPSrr, VMOVUPSrr, VMOVAPDrr, VMOVUPDrr, VMOVDQArr, VMOVDQUrr ], CheckNot<CheckSameRegOperand<0, 1>> > ]>; ``` Definitions of IsOptimizableRegisterMove from processor models of a same Target are processed by the SubtargetEmitter to auto-generate a target-specific override for each of the following predicate methods: ``` bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI) const; bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned CPUID) const; ``` By default, those methods return false (i.e. conservatively assume that there are no move elimination candidates). Tablegen class RegisterFile has been extended with the following information: - The set of register classes that allow move elimination. - Maxium number of moves that can be eliminated every cycle. - Whether move elimination is restricted to moves from registers that are known to be zero. This patch is structured in three part: A first part (which is mostly boilerplate) adds the new 'isOptimizableRegisterMove' target hooks, and extends existing register file descriptors in MC by introducing new fields to describe properties related to move elimination. A second part, uses the new tablegen constructs to describe move elimination in the BtVer2 scheduling model. A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove' hook to mark instructions that are candidates for move elimination. It also teaches class RegisterFile how to describe constraints on move elimination at PRF granularity. llvm-mca tests for btver2 show differences before/after this patch. Differential Revision: https://reviews.llvm.org/D53134 llvm-svn: 344334
2018-10-12 13:23:04 +02:00
OS << "\n// {RegisterClassID, Register Cost, AllowMoveElimination }\n";
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
OS << "static const llvm::MCRegisterCostEntry " << ProcModel.ModelName
<< "RegisterCosts"
<< "[] = {\n";
for (const CodeGenRegisterFile &RF : ProcModel.RegisterFiles) {
// Skip register files with a default cost table.
if (RF.hasDefaultCosts())
continue;
// Add entries to the cost table.
for (const CodeGenRegisterCost &RC : RF.Costs) {
OS << " { ";
Record *Rec = RC.RCDef;
if (Rec->getValue("Namespace"))
OS << Rec->getValueAsString("Namespace") << "::";
[tblgen][llvm-mca] Add the ability to describe move elimination candidates via tablegen. This patch adds the ability to identify instructions that are "move elimination candidates". It also allows scheduling models to describe processor register files that allow move elimination. A move elimination candidate is an instruction that can be eliminated at register renaming stage. Each subtarget can specify which instructions are move elimination candidates with the help of tablegen class "IsOptimizableRegisterMove" (see llvm/Target/TargetInstrPredicate.td). For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated. The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this: ``` def : IsOptimizableRegisterMove<[ InstructionEquivalenceClass<[ // GPR variants. MOV32rr, MOV64rr, // MMX variants. MMX_MOVQ64rr, // SSE variants. MOVAPSrr, MOVUPSrr, MOVAPDrr, MOVUPDrr, MOVDQArr, MOVDQUrr, // AVX variants. VMOVAPSrr, VMOVUPSrr, VMOVAPDrr, VMOVUPDrr, VMOVDQArr, VMOVDQUrr ], CheckNot<CheckSameRegOperand<0, 1>> > ]>; ``` Definitions of IsOptimizableRegisterMove from processor models of a same Target are processed by the SubtargetEmitter to auto-generate a target-specific override for each of the following predicate methods: ``` bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI) const; bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned CPUID) const; ``` By default, those methods return false (i.e. conservatively assume that there are no move elimination candidates). Tablegen class RegisterFile has been extended with the following information: - The set of register classes that allow move elimination. - Maxium number of moves that can be eliminated every cycle. - Whether move elimination is restricted to moves from registers that are known to be zero. This patch is structured in three part: A first part (which is mostly boilerplate) adds the new 'isOptimizableRegisterMove' target hooks, and extends existing register file descriptors in MC by introducing new fields to describe properties related to move elimination. A second part, uses the new tablegen constructs to describe move elimination in the BtVer2 scheduling model. A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove' hook to mark instructions that are candidates for move elimination. It also teaches class RegisterFile how to describe constraints on move elimination at PRF granularity. llvm-mca tests for btver2 show differences before/after this patch. Differential Revision: https://reviews.llvm.org/D53134 llvm-svn: 344334
2018-10-12 13:23:04 +02:00
OS << Rec->getName() << "RegClassID, " << RC.Cost << ", "
<< RC.AllowMoveElimination << "},\n";
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
}
}
OS << "};\n";
// Now generate a table with register file info.
[tblgen][llvm-mca] Add the ability to describe move elimination candidates via tablegen. This patch adds the ability to identify instructions that are "move elimination candidates". It also allows scheduling models to describe processor register files that allow move elimination. A move elimination candidate is an instruction that can be eliminated at register renaming stage. Each subtarget can specify which instructions are move elimination candidates with the help of tablegen class "IsOptimizableRegisterMove" (see llvm/Target/TargetInstrPredicate.td). For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated. The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this: ``` def : IsOptimizableRegisterMove<[ InstructionEquivalenceClass<[ // GPR variants. MOV32rr, MOV64rr, // MMX variants. MMX_MOVQ64rr, // SSE variants. MOVAPSrr, MOVUPSrr, MOVAPDrr, MOVUPDrr, MOVDQArr, MOVDQUrr, // AVX variants. VMOVAPSrr, VMOVUPSrr, VMOVAPDrr, VMOVUPDrr, VMOVDQArr, VMOVDQUrr ], CheckNot<CheckSameRegOperand<0, 1>> > ]>; ``` Definitions of IsOptimizableRegisterMove from processor models of a same Target are processed by the SubtargetEmitter to auto-generate a target-specific override for each of the following predicate methods: ``` bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI) const; bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned CPUID) const; ``` By default, those methods return false (i.e. conservatively assume that there are no move elimination candidates). Tablegen class RegisterFile has been extended with the following information: - The set of register classes that allow move elimination. - Maxium number of moves that can be eliminated every cycle. - Whether move elimination is restricted to moves from registers that are known to be zero. This patch is structured in three part: A first part (which is mostly boilerplate) adds the new 'isOptimizableRegisterMove' target hooks, and extends existing register file descriptors in MC by introducing new fields to describe properties related to move elimination. A second part, uses the new tablegen constructs to describe move elimination in the BtVer2 scheduling model. A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove' hook to mark instructions that are candidates for move elimination. It also teaches class RegisterFile how to describe constraints on move elimination at PRF granularity. llvm-mca tests for btver2 show differences before/after this patch. Differential Revision: https://reviews.llvm.org/D53134 llvm-svn: 344334
2018-10-12 13:23:04 +02:00
OS << "\n // {Name, #PhysRegs, #CostEntries, IndexToCostTbl, "
<< "MaxMovesEliminatedPerCycle, AllowZeroMoveEliminationOnly }\n";
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
OS << "static const llvm::MCRegisterFileDesc " << ProcModel.ModelName
<< "RegisterFiles"
<< "[] = {\n"
[tblgen][llvm-mca] Add the ability to describe move elimination candidates via tablegen. This patch adds the ability to identify instructions that are "move elimination candidates". It also allows scheduling models to describe processor register files that allow move elimination. A move elimination candidate is an instruction that can be eliminated at register renaming stage. Each subtarget can specify which instructions are move elimination candidates with the help of tablegen class "IsOptimizableRegisterMove" (see llvm/Target/TargetInstrPredicate.td). For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated. The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this: ``` def : IsOptimizableRegisterMove<[ InstructionEquivalenceClass<[ // GPR variants. MOV32rr, MOV64rr, // MMX variants. MMX_MOVQ64rr, // SSE variants. MOVAPSrr, MOVUPSrr, MOVAPDrr, MOVUPDrr, MOVDQArr, MOVDQUrr, // AVX variants. VMOVAPSrr, VMOVUPSrr, VMOVAPDrr, VMOVUPDrr, VMOVDQArr, VMOVDQUrr ], CheckNot<CheckSameRegOperand<0, 1>> > ]>; ``` Definitions of IsOptimizableRegisterMove from processor models of a same Target are processed by the SubtargetEmitter to auto-generate a target-specific override for each of the following predicate methods: ``` bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI) const; bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned CPUID) const; ``` By default, those methods return false (i.e. conservatively assume that there are no move elimination candidates). Tablegen class RegisterFile has been extended with the following information: - The set of register classes that allow move elimination. - Maxium number of moves that can be eliminated every cycle. - Whether move elimination is restricted to moves from registers that are known to be zero. This patch is structured in three part: A first part (which is mostly boilerplate) adds the new 'isOptimizableRegisterMove' target hooks, and extends existing register file descriptors in MC by introducing new fields to describe properties related to move elimination. A second part, uses the new tablegen constructs to describe move elimination in the BtVer2 scheduling model. A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove' hook to mark instructions that are candidates for move elimination. It also teaches class RegisterFile how to describe constraints on move elimination at PRF granularity. llvm-mca tests for btver2 show differences before/after this patch. Differential Revision: https://reviews.llvm.org/D53134 llvm-svn: 344334
2018-10-12 13:23:04 +02:00
<< " { \"InvalidRegisterFile\", 0, 0, 0, 0, 0 },\n";
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
unsigned CostTblIndex = 0;
for (const CodeGenRegisterFile &RD : ProcModel.RegisterFiles) {
OS << " { ";
OS << '"' << RD.Name << '"' << ", " << RD.NumPhysRegs << ", ";
unsigned NumCostEntries = RD.Costs.size();
[tblgen][llvm-mca] Add the ability to describe move elimination candidates via tablegen. This patch adds the ability to identify instructions that are "move elimination candidates". It also allows scheduling models to describe processor register files that allow move elimination. A move elimination candidate is an instruction that can be eliminated at register renaming stage. Each subtarget can specify which instructions are move elimination candidates with the help of tablegen class "IsOptimizableRegisterMove" (see llvm/Target/TargetInstrPredicate.td). For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated. The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this: ``` def : IsOptimizableRegisterMove<[ InstructionEquivalenceClass<[ // GPR variants. MOV32rr, MOV64rr, // MMX variants. MMX_MOVQ64rr, // SSE variants. MOVAPSrr, MOVUPSrr, MOVAPDrr, MOVUPDrr, MOVDQArr, MOVDQUrr, // AVX variants. VMOVAPSrr, VMOVUPSrr, VMOVAPDrr, VMOVUPDrr, VMOVDQArr, VMOVDQUrr ], CheckNot<CheckSameRegOperand<0, 1>> > ]>; ``` Definitions of IsOptimizableRegisterMove from processor models of a same Target are processed by the SubtargetEmitter to auto-generate a target-specific override for each of the following predicate methods: ``` bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI) const; bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned CPUID) const; ``` By default, those methods return false (i.e. conservatively assume that there are no move elimination candidates). Tablegen class RegisterFile has been extended with the following information: - The set of register classes that allow move elimination. - Maxium number of moves that can be eliminated every cycle. - Whether move elimination is restricted to moves from registers that are known to be zero. This patch is structured in three part: A first part (which is mostly boilerplate) adds the new 'isOptimizableRegisterMove' target hooks, and extends existing register file descriptors in MC by introducing new fields to describe properties related to move elimination. A second part, uses the new tablegen constructs to describe move elimination in the BtVer2 scheduling model. A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove' hook to mark instructions that are candidates for move elimination. It also teaches class RegisterFile how to describe constraints on move elimination at PRF granularity. llvm-mca tests for btver2 show differences before/after this patch. Differential Revision: https://reviews.llvm.org/D53134 llvm-svn: 344334
2018-10-12 13:23:04 +02:00
OS << NumCostEntries << ", " << CostTblIndex << ", "
<< RD.MaxMovesEliminatedPerCycle << ", "
<< RD.AllowZeroMoveEliminationOnly << "},\n";
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
CostTblIndex += NumCostEntries;
}
OS << "};\n";
return CostTblIndex;
}
[llvm-mca][MC] Add the ability to declare which processor resources model load/store queues (PR36666). This patch adds the ability to specify via tablegen which processor resources are load/store queue resources. A new tablegen class named MemoryQueue can be optionally used to mark resources that model load/store queues. Information about the load/store queue is collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and `StoreQueueID`. Those two fields are identifiers for buffered resources used to describe the load queue and the store queue. Field `BufferSize` is interpreted as the number of entries in the queue, while the number of units is a throughput indicator (i.e. number of available pickers for loads/stores). At construction time, LSUnit in llvm-mca checks for the presence of extra processor information (i.e. MCExtraProcessorInfo) in the scheduling model. If that information is available, and fields LoadQueueID and StoreQueueID are set to a value different than zero (i.e. the invalid processor resource index), then LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value declared by the two processor resources. With this patch, we more accurately track dynamic dispatch stalls caused by the lack of LS tokens (i.e. load/store queue full). This is also shown by the differences in two BdVer2 tests. Stalls that were previously classified as generic SCHEDULER FULL stalls, are not correctly classified either as "load queue full" or "store queue full". About the differences in the -scheduler-stats view: those differences are expected, because entries in the load/store queue are not released at instruction issue stage. Instead, those are released at instruction executed stage. This is the main reason why for the modified tests, the load/store queues gets full before PdEx is full. Differential Revision: https://reviews.llvm.org/D54957 llvm-svn: 347857
2018-11-29 13:15:56 +01:00
void SubtargetEmitter::EmitLoadStoreQueueInfo(const CodeGenProcModel &ProcModel,
raw_ostream &OS) {
unsigned QueueID = 0;
if (ProcModel.LoadQueue) {
const Record *Queue = ProcModel.LoadQueue->getValueAsDef("QueueDescriptor");
2021-01-20 05:19:14 +01:00
QueueID = 1 + std::distance(ProcModel.ProcResourceDefs.begin(),
find(ProcModel.ProcResourceDefs, Queue));
[llvm-mca][MC] Add the ability to declare which processor resources model load/store queues (PR36666). This patch adds the ability to specify via tablegen which processor resources are load/store queue resources. A new tablegen class named MemoryQueue can be optionally used to mark resources that model load/store queues. Information about the load/store queue is collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and `StoreQueueID`. Those two fields are identifiers for buffered resources used to describe the load queue and the store queue. Field `BufferSize` is interpreted as the number of entries in the queue, while the number of units is a throughput indicator (i.e. number of available pickers for loads/stores). At construction time, LSUnit in llvm-mca checks for the presence of extra processor information (i.e. MCExtraProcessorInfo) in the scheduling model. If that information is available, and fields LoadQueueID and StoreQueueID are set to a value different than zero (i.e. the invalid processor resource index), then LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value declared by the two processor resources. With this patch, we more accurately track dynamic dispatch stalls caused by the lack of LS tokens (i.e. load/store queue full). This is also shown by the differences in two BdVer2 tests. Stalls that were previously classified as generic SCHEDULER FULL stalls, are not correctly classified either as "load queue full" or "store queue full". About the differences in the -scheduler-stats view: those differences are expected, because entries in the load/store queue are not released at instruction issue stage. Instead, those are released at instruction executed stage. This is the main reason why for the modified tests, the load/store queues gets full before PdEx is full. Differential Revision: https://reviews.llvm.org/D54957 llvm-svn: 347857
2018-11-29 13:15:56 +01:00
}
OS << " " << QueueID << ", // Resource Descriptor for the Load Queue\n";
QueueID = 0;
if (ProcModel.StoreQueue) {
const Record *Queue =
ProcModel.StoreQueue->getValueAsDef("QueueDescriptor");
2021-01-20 05:19:14 +01:00
QueueID = 1 + std::distance(ProcModel.ProcResourceDefs.begin(),
find(ProcModel.ProcResourceDefs, Queue));
[llvm-mca][MC] Add the ability to declare which processor resources model load/store queues (PR36666). This patch adds the ability to specify via tablegen which processor resources are load/store queue resources. A new tablegen class named MemoryQueue can be optionally used to mark resources that model load/store queues. Information about the load/store queue is collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and `StoreQueueID`. Those two fields are identifiers for buffered resources used to describe the load queue and the store queue. Field `BufferSize` is interpreted as the number of entries in the queue, while the number of units is a throughput indicator (i.e. number of available pickers for loads/stores). At construction time, LSUnit in llvm-mca checks for the presence of extra processor information (i.e. MCExtraProcessorInfo) in the scheduling model. If that information is available, and fields LoadQueueID and StoreQueueID are set to a value different than zero (i.e. the invalid processor resource index), then LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value declared by the two processor resources. With this patch, we more accurately track dynamic dispatch stalls caused by the lack of LS tokens (i.e. load/store queue full). This is also shown by the differences in two BdVer2 tests. Stalls that were previously classified as generic SCHEDULER FULL stalls, are not correctly classified either as "load queue full" or "store queue full". About the differences in the -scheduler-stats view: those differences are expected, because entries in the load/store queue are not released at instruction issue stage. Instead, those are released at instruction executed stage. This is the main reason why for the modified tests, the load/store queues gets full before PdEx is full. Differential Revision: https://reviews.llvm.org/D54957 llvm-svn: 347857
2018-11-29 13:15:56 +01:00
}
OS << " " << QueueID << ", // Resource Descriptor for the Store Queue\n";
}
void SubtargetEmitter::EmitExtraProcessorInfo(const CodeGenProcModel &ProcModel,
raw_ostream &OS) {
// Generate a table of register file descriptors (one entry per each user
// defined register file), and a table of register costs.
unsigned NumCostEntries = EmitRegisterFileTables(ProcModel, OS);
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
// Now generate a table for the extra processor info.
OS << "\nstatic const llvm::MCExtraProcessorInfo " << ProcModel.ModelName
<< "ExtraInfo = {\n ";
// Add information related to the retire control unit.
EmitRetireControlUnitInfo(ProcModel, OS);
// Add information related to the register files (i.e. where to find register
// file descriptors and register costs).
EmitRegisterFileInfo(ProcModel, ProcModel.RegisterFiles.size(),
NumCostEntries, OS);
[llvm-mca][MC] Add the ability to declare which processor resources model load/store queues (PR36666). This patch adds the ability to specify via tablegen which processor resources are load/store queue resources. A new tablegen class named MemoryQueue can be optionally used to mark resources that model load/store queues. Information about the load/store queue is collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and `StoreQueueID`. Those two fields are identifiers for buffered resources used to describe the load queue and the store queue. Field `BufferSize` is interpreted as the number of entries in the queue, while the number of units is a throughput indicator (i.e. number of available pickers for loads/stores). At construction time, LSUnit in llvm-mca checks for the presence of extra processor information (i.e. MCExtraProcessorInfo) in the scheduling model. If that information is available, and fields LoadQueueID and StoreQueueID are set to a value different than zero (i.e. the invalid processor resource index), then LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value declared by the two processor resources. With this patch, we more accurately track dynamic dispatch stalls caused by the lack of LS tokens (i.e. load/store queue full). This is also shown by the differences in two BdVer2 tests. Stalls that were previously classified as generic SCHEDULER FULL stalls, are not correctly classified either as "load queue full" or "store queue full". About the differences in the -scheduler-stats view: those differences are expected, because entries in the load/store queue are not released at instruction issue stage. Instead, those are released at instruction executed stage. This is the main reason why for the modified tests, the load/store queues gets full before PdEx is full. Differential Revision: https://reviews.llvm.org/D54957 llvm-svn: 347857
2018-11-29 13:15:56 +01:00
// Add information about load/store queues.
EmitLoadStoreQueueInfo(ProcModel, OS);
OS << "};\n";
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
}
void SubtargetEmitter::EmitProcessorResources(const CodeGenProcModel &ProcModel,
raw_ostream &OS) {
EmitProcessorResourceSubUnits(ProcModel, OS);
OS << "\n// {Name, NumUnits, SuperIdx, BufferSize, SubUnitsIdxBegin}\n";
OS << "static const llvm::MCProcResourceDesc " << ProcModel.ModelName
<< "ProcResources"
<< "[] = {\n"
<< " {\"InvalidUnit\", 0, 0, 0, 0},\n";
unsigned SubUnitsOffset = 1;
for (unsigned i = 0, e = ProcModel.ProcResourceDefs.size(); i < e; ++i) {
Record *PRDef = ProcModel.ProcResourceDefs[i];
Record *SuperDef = nullptr;
unsigned SuperIdx = 0;
unsigned NumUnits = 0;
const unsigned SubUnitsBeginOffset = SubUnitsOffset;
int BufferSize = PRDef->getValueAsInt("BufferSize");
if (PRDef->isSubClassOf("ProcResGroup")) {
RecVec ResUnits = PRDef->getValueAsListOfDefs("Resources");
for (Record *RU : ResUnits) {
NumUnits += RU->getValueAsInt("NumUnits");
SubUnitsOffset += RU->getValueAsInt("NumUnits");
}
}
else {
// Find the SuperIdx
if (PRDef->getValueInit("Super")->isComplete()) {
SuperDef =
SchedModels.findProcResUnits(PRDef->getValueAsDef("Super"),
ProcModel, PRDef->getLoc());
SuperIdx = ProcModel.getProcResourceIdx(SuperDef);
}
NumUnits = PRDef->getValueAsInt("NumUnits");
}
// Emit the ProcResourceDesc
OS << " {\"" << PRDef->getName() << "\", ";
if (PRDef->getName().size() < 15)
OS.indent(15 - PRDef->getName().size());
OS << NumUnits << ", " << SuperIdx << ", " << BufferSize << ", ";
if (SubUnitsBeginOffset != SubUnitsOffset) {
OS << ProcModel.ModelName << "ProcResourceSubUnits + "
<< SubUnitsBeginOffset;
} else {
OS << "nullptr";
}
OS << "}, // #" << i+1;
if (SuperDef)
OS << ", Super=" << SuperDef->getName();
OS << "\n";
}
OS << "};\n";
}
// Find the WriteRes Record that defines processor resources for this
// SchedWrite.
Record *SubtargetEmitter::FindWriteResources(
const CodeGenSchedRW &SchedWrite, const CodeGenProcModel &ProcModel) {
// Check if the SchedWrite is already subtarget-specific and directly
// specifies a set of processor resources.
if (SchedWrite.TheDef->isSubClassOf("SchedWriteRes"))
return SchedWrite.TheDef;
Record *AliasDef = nullptr;
for (Record *A : SchedWrite.Aliases) {
const CodeGenSchedRW &AliasRW =
SchedModels.getSchedRW(A->getValueAsDef("AliasRW"));
if (AliasRW.TheDef->getValueInit("SchedModel")->isComplete()) {
Record *ModelDef = AliasRW.TheDef->getValueAsDef("SchedModel");
if (&SchedModels.getProcModel(ModelDef) != &ProcModel)
continue;
}
if (AliasDef)
PrintFatalError(AliasRW.TheDef->getLoc(), "Multiple aliases "
"defined for processor " + ProcModel.ModelName +
" Ensure only one SchedAlias exists per RW.");
AliasDef = AliasRW.TheDef;
}
if (AliasDef && AliasDef->isSubClassOf("SchedWriteRes"))
return AliasDef;
// Check this processor's list of write resources.
Record *ResDef = nullptr;
for (Record *WR : ProcModel.WriteResDefs) {
if (!WR->isSubClassOf("WriteRes"))
continue;
if (AliasDef == WR->getValueAsDef("WriteType")
|| SchedWrite.TheDef == WR->getValueAsDef("WriteType")) {
if (ResDef) {
PrintFatalError(WR->getLoc(), "Resources are defined for both "
"SchedWrite and its alias on processor " +
ProcModel.ModelName);
}
ResDef = WR;
}
}
// TODO: If ProcModel has a base model (previous generation processor),
// then call FindWriteResources recursively with that model here.
if (!ResDef) {
PrintFatalError(ProcModel.ModelDef->getLoc(),
Twine("Processor does not define resources for ") +
SchedWrite.TheDef->getName());
}
return ResDef;
}
/// Find the ReadAdvance record for the given SchedRead on this processor or
/// return NULL.
Record *SubtargetEmitter::FindReadAdvance(const CodeGenSchedRW &SchedRead,
const CodeGenProcModel &ProcModel) {
// Check for SchedReads that directly specify a ReadAdvance.
if (SchedRead.TheDef->isSubClassOf("SchedReadAdvance"))
return SchedRead.TheDef;
// Check this processor's list of aliases for SchedRead.
Record *AliasDef = nullptr;
for (Record *A : SchedRead.Aliases) {
const CodeGenSchedRW &AliasRW =
SchedModels.getSchedRW(A->getValueAsDef("AliasRW"));
if (AliasRW.TheDef->getValueInit("SchedModel")->isComplete()) {
Record *ModelDef = AliasRW.TheDef->getValueAsDef("SchedModel");
if (&SchedModels.getProcModel(ModelDef) != &ProcModel)
continue;
}
if (AliasDef)
PrintFatalError(AliasRW.TheDef->getLoc(), "Multiple aliases "
"defined for processor " + ProcModel.ModelName +
" Ensure only one SchedAlias exists per RW.");
AliasDef = AliasRW.TheDef;
}
if (AliasDef && AliasDef->isSubClassOf("SchedReadAdvance"))
return AliasDef;
// Check this processor's ReadAdvanceList.
Record *ResDef = nullptr;
for (Record *RA : ProcModel.ReadAdvanceDefs) {
if (!RA->isSubClassOf("ReadAdvance"))
continue;
if (AliasDef == RA->getValueAsDef("ReadType")
|| SchedRead.TheDef == RA->getValueAsDef("ReadType")) {
if (ResDef) {
PrintFatalError(RA->getLoc(), "Resources are defined for both "
"SchedRead and its alias on processor " +
ProcModel.ModelName);
}
ResDef = RA;
}
}
// TODO: If ProcModel has a base model (previous generation processor),
// then call FindReadAdvance recursively with that model here.
if (!ResDef && SchedRead.TheDef->getName() != "ReadDefault") {
PrintFatalError(ProcModel.ModelDef->getLoc(),
Twine("Processor does not define resources for ") +
SchedRead.TheDef->getName());
}
return ResDef;
}
// Expand an explicit list of processor resources into a full list of implied
// resource groups and super resources that cover them.
void SubtargetEmitter::ExpandProcResources(RecVec &PRVec,
std::vector<int64_t> &Cycles,
const CodeGenProcModel &PM) {
assert(PRVec.size() == Cycles.size() && "failed precondition");
for (unsigned i = 0, e = PRVec.size(); i != e; ++i) {
Record *PRDef = PRVec[i];
RecVec SubResources;
if (PRDef->isSubClassOf("ProcResGroup"))
SubResources = PRDef->getValueAsListOfDefs("Resources");
else {
SubResources.push_back(PRDef);
PRDef = SchedModels.findProcResUnits(PRDef, PM, PRDef->getLoc());
for (Record *SubDef = PRDef;
SubDef->getValueInit("Super")->isComplete();) {
if (SubDef->isSubClassOf("ProcResGroup")) {
// Disallow this for simplicitly.
PrintFatalError(SubDef->getLoc(), "Processor resource group "
" cannot be a super resources.");
}
Record *SuperDef =
SchedModels.findProcResUnits(SubDef->getValueAsDef("Super"), PM,
SubDef->getLoc());
PRVec.push_back(SuperDef);
Cycles.push_back(Cycles[i]);
SubDef = SuperDef;
}
}
for (Record *PR : PM.ProcResourceDefs) {
if (PR == PRDef || !PR->isSubClassOf("ProcResGroup"))
continue;
RecVec SuperResources = PR->getValueAsListOfDefs("Resources");
RecIter SubI = SubResources.begin(), SubE = SubResources.end();
for( ; SubI != SubE; ++SubI) {
if (!is_contained(SuperResources, *SubI)) {
break;
}
}
if (SubI == SubE) {
PRVec.push_back(PR);
Cycles.push_back(Cycles[i]);
}
}
}
}
// Generate the SchedClass table for this processor and update global
// tables. Must be called for each processor in order.
void SubtargetEmitter::GenSchedClassTables(const CodeGenProcModel &ProcModel,
SchedClassTables &SchedTables) {
SchedTables.ProcSchedClasses.resize(SchedTables.ProcSchedClasses.size() + 1);
if (!ProcModel.hasInstrSchedModel())
return;
std::vector<MCSchedClassDesc> &SCTab = SchedTables.ProcSchedClasses.back();
LLVM_DEBUG(dbgs() << "\n+++ SCHED CLASSES (GenSchedClassTables) +++\n");
for (const CodeGenSchedClass &SC : SchedModels.schedClasses()) {
LLVM_DEBUG(SC.dump(&SchedModels));
SCTab.resize(SCTab.size() + 1);
MCSchedClassDesc &SCDesc = SCTab.back();
// SCDesc.Name is guarded by NDEBUG
SCDesc.NumMicroOps = 0;
SCDesc.BeginGroup = false;
SCDesc.EndGroup = false;
SCDesc.RetireOOO = false;
SCDesc.WriteProcResIdx = 0;
SCDesc.WriteLatencyIdx = 0;
SCDesc.ReadAdvanceIdx = 0;
// A Variant SchedClass has no resources of its own.
bool HasVariants = false;
for (const CodeGenSchedTransition &CGT :
make_range(SC.Transitions.begin(), SC.Transitions.end())) {
if (CGT.ProcIndex == ProcModel.Index) {
HasVariants = true;
break;
}
}
if (HasVariants) {
SCDesc.NumMicroOps = MCSchedClassDesc::VariantNumMicroOps;
continue;
}
// Determine if the SchedClass is actually reachable on this processor. If
// not don't try to locate the processor resources, it will fail.
// If ProcIndices contains 0, this class applies to all processors.
assert(!SC.ProcIndices.empty() && "expect at least one procidx");
if (SC.ProcIndices[0] != 0) {
if (!is_contained(SC.ProcIndices, ProcModel.Index))
continue;
}
IdxVec Writes = SC.Writes;
IdxVec Reads = SC.Reads;
if (!SC.InstRWs.empty()) {
// This class has a default ReadWrite list which can be overridden by
// InstRW definitions.
Record *RWDef = nullptr;
for (Record *RW : SC.InstRWs) {
Record *RWModelDef = RW->getValueAsDef("SchedModel");
if (&ProcModel == &SchedModels.getProcModel(RWModelDef)) {
RWDef = RW;
break;
}
}
if (RWDef) {
Writes.clear();
Reads.clear();
SchedModels.findRWs(RWDef->getValueAsListOfDefs("OperandReadWrites"),
Writes, Reads);
}
}
if (Writes.empty()) {
// Check this processor's itinerary class resources.
for (Record *I : ProcModel.ItinRWDefs) {
RecVec Matched = I->getValueAsListOfDefs("MatchedItinClasses");
if (is_contained(Matched, SC.ItinClassDef)) {
SchedModels.findRWs(I->getValueAsListOfDefs("OperandReadWrites"),
Writes, Reads);
break;
}
}
if (Writes.empty()) {
LLVM_DEBUG(dbgs() << ProcModel.ModelName
<< " does not have resources for class " << SC.Name
<< '\n');
SCDesc.NumMicroOps = MCSchedClassDesc::InvalidNumMicroOps;
}
}
// Sum resources across all operand writes.
std::vector<MCWriteProcResEntry> WriteProcResources;
std::vector<MCWriteLatencyEntry> WriteLatencies;
std::vector<std::string> WriterNames;
std::vector<MCReadAdvanceEntry> ReadAdvanceEntries;
for (unsigned W : Writes) {
IdxVec WriteSeq;
SchedModels.expandRWSeqForProc(W, WriteSeq, /*IsRead=*/false,
ProcModel);
// For each operand, create a latency entry.
MCWriteLatencyEntry WLEntry;
WLEntry.Cycles = 0;
unsigned WriteID = WriteSeq.back();
WriterNames.push_back(SchedModels.getSchedWrite(WriteID).Name);
// If this Write is not referenced by a ReadAdvance, don't distinguish it
// from other WriteLatency entries.
if (!SchedModels.hasReadOfWrite(
SchedModels.getSchedWrite(WriteID).TheDef)) {
WriteID = 0;
}
WLEntry.WriteResourceID = WriteID;
for (unsigned WS : WriteSeq) {
Record *WriteRes =
FindWriteResources(SchedModels.getSchedWrite(WS), ProcModel);
// Mark the parent class as invalid for unsupported write types.
if (WriteRes->getValueAsBit("Unsupported")) {
SCDesc.NumMicroOps = MCSchedClassDesc::InvalidNumMicroOps;
break;
}
WLEntry.Cycles += WriteRes->getValueAsInt("Latency");
SCDesc.NumMicroOps += WriteRes->getValueAsInt("NumMicroOps");
SCDesc.BeginGroup |= WriteRes->getValueAsBit("BeginGroup");
SCDesc.EndGroup |= WriteRes->getValueAsBit("EndGroup");
SCDesc.BeginGroup |= WriteRes->getValueAsBit("SingleIssue");
SCDesc.EndGroup |= WriteRes->getValueAsBit("SingleIssue");
SCDesc.RetireOOO |= WriteRes->getValueAsBit("RetireOOO");
// Create an entry for each ProcResource listed in WriteRes.
RecVec PRVec = WriteRes->getValueAsListOfDefs("ProcResources");
std::vector<int64_t> Cycles =
WriteRes->getValueAsListOfInts("ResourceCycles");
if (Cycles.empty()) {
// If ResourceCycles is not provided, default to one cycle per
// resource.
Cycles.resize(PRVec.size(), 1);
} else if (Cycles.size() != PRVec.size()) {
// If ResourceCycles is provided, check consistency.
PrintFatalError(
WriteRes->getLoc(),
Twine("Inconsistent resource cycles: !size(ResourceCycles) != "
"!size(ProcResources): ")
.concat(Twine(PRVec.size()))
.concat(" vs ")
.concat(Twine(Cycles.size())));
}
ExpandProcResources(PRVec, Cycles, ProcModel);
for (unsigned PRIdx = 0, PREnd = PRVec.size();
PRIdx != PREnd; ++PRIdx) {
MCWriteProcResEntry WPREntry;
WPREntry.ProcResourceIdx = ProcModel.getProcResourceIdx(PRVec[PRIdx]);
assert(WPREntry.ProcResourceIdx && "Bad ProcResourceIdx");
WPREntry.Cycles = Cycles[PRIdx];
// If this resource is already used in this sequence, add the current
// entry's cycles so that the same resource appears to be used
// serially, rather than multiple parallel uses. This is important for
// in-order machine where the resource consumption is a hazard.
unsigned WPRIdx = 0, WPREnd = WriteProcResources.size();
for( ; WPRIdx != WPREnd; ++WPRIdx) {
if (WriteProcResources[WPRIdx].ProcResourceIdx
== WPREntry.ProcResourceIdx) {
WriteProcResources[WPRIdx].Cycles += WPREntry.Cycles;
break;
}
}
if (WPRIdx == WPREnd)
WriteProcResources.push_back(WPREntry);
}
}
WriteLatencies.push_back(WLEntry);
}
// Create an entry for each operand Read in this SchedClass.
// Entries must be sorted first by UseIdx then by WriteResourceID.
for (unsigned UseIdx = 0, EndIdx = Reads.size();
UseIdx != EndIdx; ++UseIdx) {
Record *ReadAdvance =
FindReadAdvance(SchedModels.getSchedRead(Reads[UseIdx]), ProcModel);
if (!ReadAdvance)
continue;
// Mark the parent class as invalid for unsupported write types.
if (ReadAdvance->getValueAsBit("Unsupported")) {
SCDesc.NumMicroOps = MCSchedClassDesc::InvalidNumMicroOps;
break;
}
RecVec ValidWrites = ReadAdvance->getValueAsListOfDefs("ValidWrites");
IdxVec WriteIDs;
if (ValidWrites.empty())
WriteIDs.push_back(0);
else {
for (Record *VW : ValidWrites) {
WriteIDs.push_back(SchedModels.getSchedRWIdx(VW, /*IsRead=*/false));
}
}
llvm::sort(WriteIDs);
for(unsigned W : WriteIDs) {
MCReadAdvanceEntry RAEntry;
RAEntry.UseIdx = UseIdx;
RAEntry.WriteResourceID = W;
RAEntry.Cycles = ReadAdvance->getValueAsInt("Cycles");
ReadAdvanceEntries.push_back(RAEntry);
}
}
if (SCDesc.NumMicroOps == MCSchedClassDesc::InvalidNumMicroOps) {
WriteProcResources.clear();
WriteLatencies.clear();
ReadAdvanceEntries.clear();
}
// Add the information for this SchedClass to the global tables using basic
// compression.
//
// WritePrecRes entries are sorted by ProcResIdx.
llvm::sort(WriteProcResources, LessWriteProcResources());
SCDesc.NumWriteProcResEntries = WriteProcResources.size();
std::vector<MCWriteProcResEntry>::iterator WPRPos =
std::search(SchedTables.WriteProcResources.begin(),
SchedTables.WriteProcResources.end(),
WriteProcResources.begin(), WriteProcResources.end());
if (WPRPos != SchedTables.WriteProcResources.end())
SCDesc.WriteProcResIdx = WPRPos - SchedTables.WriteProcResources.begin();
else {
SCDesc.WriteProcResIdx = SchedTables.WriteProcResources.size();
SchedTables.WriteProcResources.insert(WPRPos, WriteProcResources.begin(),
WriteProcResources.end());
}
// Latency entries must remain in operand order.
SCDesc.NumWriteLatencyEntries = WriteLatencies.size();
std::vector<MCWriteLatencyEntry>::iterator WLPos =
std::search(SchedTables.WriteLatencies.begin(),
SchedTables.WriteLatencies.end(),
WriteLatencies.begin(), WriteLatencies.end());
if (WLPos != SchedTables.WriteLatencies.end()) {
unsigned idx = WLPos - SchedTables.WriteLatencies.begin();
SCDesc.WriteLatencyIdx = idx;
for (unsigned i = 0, e = WriteLatencies.size(); i < e; ++i)
if (SchedTables.WriterNames[idx + i].find(WriterNames[i]) ==
std::string::npos) {
SchedTables.WriterNames[idx + i] += std::string("_") + WriterNames[i];
}
}
else {
SCDesc.WriteLatencyIdx = SchedTables.WriteLatencies.size();
llvm::append_range(SchedTables.WriteLatencies, WriteLatencies);
llvm::append_range(SchedTables.WriterNames, WriterNames);
}
// ReadAdvanceEntries must remain in operand order.
SCDesc.NumReadAdvanceEntries = ReadAdvanceEntries.size();
std::vector<MCReadAdvanceEntry>::iterator RAPos =
std::search(SchedTables.ReadAdvanceEntries.begin(),
SchedTables.ReadAdvanceEntries.end(),
ReadAdvanceEntries.begin(), ReadAdvanceEntries.end());
if (RAPos != SchedTables.ReadAdvanceEntries.end())
SCDesc.ReadAdvanceIdx = RAPos - SchedTables.ReadAdvanceEntries.begin();
else {
SCDesc.ReadAdvanceIdx = SchedTables.ReadAdvanceEntries.size();
llvm::append_range(SchedTables.ReadAdvanceEntries, ReadAdvanceEntries);
}
}
}
// Emit SchedClass tables for all processors and associated global tables.
void SubtargetEmitter::EmitSchedClassTables(SchedClassTables &SchedTables,
raw_ostream &OS) {
// Emit global WriteProcResTable.
OS << "\n// {ProcResourceIdx, Cycles}\n"
<< "extern const llvm::MCWriteProcResEntry "
<< Target << "WriteProcResTable[] = {\n"
<< " { 0, 0}, // Invalid\n";
for (unsigned WPRIdx = 1, WPREnd = SchedTables.WriteProcResources.size();
WPRIdx != WPREnd; ++WPRIdx) {
MCWriteProcResEntry &WPREntry = SchedTables.WriteProcResources[WPRIdx];
OS << " {" << format("%2d", WPREntry.ProcResourceIdx) << ", "
<< format("%2d", WPREntry.Cycles) << "}";
if (WPRIdx + 1 < WPREnd)
OS << ',';
OS << " // #" << WPRIdx << '\n';
}
OS << "}; // " << Target << "WriteProcResTable\n";
// Emit global WriteLatencyTable.
OS << "\n// {Cycles, WriteResourceID}\n"
<< "extern const llvm::MCWriteLatencyEntry "
<< Target << "WriteLatencyTable[] = {\n"
<< " { 0, 0}, // Invalid\n";
for (unsigned WLIdx = 1, WLEnd = SchedTables.WriteLatencies.size();
WLIdx != WLEnd; ++WLIdx) {
MCWriteLatencyEntry &WLEntry = SchedTables.WriteLatencies[WLIdx];
OS << " {" << format("%2d", WLEntry.Cycles) << ", "
<< format("%2d", WLEntry.WriteResourceID) << "}";
if (WLIdx + 1 < WLEnd)
OS << ',';
OS << " // #" << WLIdx << " " << SchedTables.WriterNames[WLIdx] << '\n';
}
OS << "}; // " << Target << "WriteLatencyTable\n";
// Emit global ReadAdvanceTable.
OS << "\n// {UseIdx, WriteResourceID, Cycles}\n"
<< "extern const llvm::MCReadAdvanceEntry "
<< Target << "ReadAdvanceTable[] = {\n"
<< " {0, 0, 0}, // Invalid\n";
for (unsigned RAIdx = 1, RAEnd = SchedTables.ReadAdvanceEntries.size();
RAIdx != RAEnd; ++RAIdx) {
MCReadAdvanceEntry &RAEntry = SchedTables.ReadAdvanceEntries[RAIdx];
OS << " {" << RAEntry.UseIdx << ", "
<< format("%2d", RAEntry.WriteResourceID) << ", "
<< format("%2d", RAEntry.Cycles) << "}";
if (RAIdx + 1 < RAEnd)
OS << ',';
OS << " // #" << RAIdx << '\n';
}
OS << "}; // " << Target << "ReadAdvanceTable\n";
// Emit a SchedClass table for each processor.
for (CodeGenSchedModels::ProcIter PI = SchedModels.procModelBegin(),
PE = SchedModels.procModelEnd(); PI != PE; ++PI) {
if (!PI->hasInstrSchedModel())
continue;
std::vector<MCSchedClassDesc> &SCTab =
SchedTables.ProcSchedClasses[1 + (PI - SchedModels.procModelBegin())];
OS << "\n// {Name, NumMicroOps, BeginGroup, EndGroup, RetireOOO,"
<< " WriteProcResIdx,#, WriteLatencyIdx,#, ReadAdvanceIdx,#}\n";
OS << "static const llvm::MCSchedClassDesc "
<< PI->ModelName << "SchedClasses[] = {\n";
// The first class is always invalid. We no way to distinguish it except by
// name and position.
assert(SchedModels.getSchedClass(0).Name == "NoInstrModel"
&& "invalid class not first");
OS << " {DBGFIELD(\"InvalidSchedClass\") "
<< MCSchedClassDesc::InvalidNumMicroOps
<< ", false, false, false, 0, 0, 0, 0, 0, 0},\n";
for (unsigned SCIdx = 1, SCEnd = SCTab.size(); SCIdx != SCEnd; ++SCIdx) {
MCSchedClassDesc &MCDesc = SCTab[SCIdx];
const CodeGenSchedClass &SchedClass = SchedModels.getSchedClass(SCIdx);
OS << " {DBGFIELD(\"" << SchedClass.Name << "\") ";
if (SchedClass.Name.size() < 18)
OS.indent(18 - SchedClass.Name.size());
OS << MCDesc.NumMicroOps
<< ", " << ( MCDesc.BeginGroup ? "true" : "false" )
<< ", " << ( MCDesc.EndGroup ? "true" : "false" )
<< ", " << ( MCDesc.RetireOOO ? "true" : "false" )
<< ", " << format("%2d", MCDesc.WriteProcResIdx)
<< ", " << MCDesc.NumWriteProcResEntries
<< ", " << format("%2d", MCDesc.WriteLatencyIdx)
<< ", " << MCDesc.NumWriteLatencyEntries
<< ", " << format("%2d", MCDesc.ReadAdvanceIdx)
<< ", " << MCDesc.NumReadAdvanceEntries
<< "}, // #" << SCIdx << '\n';
}
OS << "}; // " << PI->ModelName << "SchedClasses\n";
}
}
void SubtargetEmitter::EmitProcessorModels(raw_ostream &OS) {
// For each processor model.
for (const CodeGenProcModel &PM : SchedModels.procModels()) {
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
// Emit extra processor info if available.
if (PM.hasExtraProcessorInfo())
EmitExtraProcessorInfo(PM, OS);
// Emit processor resource table.
if (PM.hasInstrSchedModel())
EmitProcessorResources(PM, OS);
else if(!PM.ProcResourceDefs.empty())
PrintFatalError(PM.ModelDef->getLoc(), "SchedMachineModel defines "
"ProcResources without defining WriteRes SchedWriteRes");
// Begin processor itinerary properties
OS << "\n";
OS << "static const llvm::MCSchedModel " << PM.ModelName << " = {\n";
EmitProcessorProp(OS, PM.ModelDef, "IssueWidth", ',');
EmitProcessorProp(OS, PM.ModelDef, "MicroOpBufferSize", ',');
EmitProcessorProp(OS, PM.ModelDef, "LoopMicroOpBufferSize", ',');
EmitProcessorProp(OS, PM.ModelDef, "LoadLatency", ',');
EmitProcessorProp(OS, PM.ModelDef, "HighLatency", ',');
EmitProcessorProp(OS, PM.ModelDef, "MispredictPenalty", ',');
bool PostRAScheduler =
(PM.ModelDef ? PM.ModelDef->getValueAsBit("PostRAScheduler") : false);
OS << " " << (PostRAScheduler ? "true" : "false") << ", // "
<< "PostRAScheduler\n";
bool CompleteModel =
(PM.ModelDef ? PM.ModelDef->getValueAsBit("CompleteModel") : false);
OS << " " << (CompleteModel ? "true" : "false") << ", // "
<< "CompleteModel\n";
OS << " " << PM.Index << ", // Processor ID\n";
if (PM.hasInstrSchedModel())
OS << " " << PM.ModelName << "ProcResources" << ",\n"
<< " " << PM.ModelName << "SchedClasses" << ",\n"
<< " " << PM.ProcResourceDefs.size()+1 << ",\n"
<< " " << (SchedModels.schedClassEnd()
- SchedModels.schedClassBegin()) << ",\n";
else
OS << " nullptr, nullptr, 0, 0,"
<< " // No instruction-level machine model.\n";
if (PM.hasItineraries())
[MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca This patch allows the description of register files in processor scheduling models. This addresses PR36662. A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td. Targets can optionally describe register files for their processors using that class. In particular, class RegisterFile allows to specify: - The total number of physical registers. - Which target registers are accessible through the register file. - The cost of allocating a register at register renaming stage. Example (from this patch - see file X86/X86ScheduleBtVer2.td) def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]> Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar (btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM register definitions only cost 1 physical register. The syntax allows to specify an empty set of register classes. An empty set of register classes means: this register file models all the registers specified by the Target. For each register class, users can specify an optional register cost. By default, register costs default to 1. A value of 0 for the number of physical registers means: "this register file has an unbounded number of physical registers". This patch is structured in two parts. * Part 1 - MC/Tablegen * A first part adds the tablegen definition of RegisterFile, and teaches the SubtargetEmitter how to emit information related to register files. Information about register files is accessible through an instance of MCExtraProcessorInfo. The idea behind this design is to logically partition the processor description which is only used by external tools (like llvm-mca) from the processor information used by the llvm machine schedulers. I think that this design would make easier for targets to get rid of the extra processor information if they don't want it. * Part 2 - llvm-mca related * The second part of this patch is related to changes to llvm-mca. The main differences are: 1) class RegisterFile now needs to take into account the "cost of a register" when allocating physical registers at register renaming stage. 2) Point 1. triggered a minor refactoring which lef to the removal of the "maximum 32 register files" restriction. 3) The BackendStatistics view has been updated so that we can print out extra details related to each register file implemented by the processor. The effect of point 3. is also visible in tests register-files-[1..5].s. Differential Revision: https://reviews.llvm.org/D44980 llvm-svn: 329067
2018-04-03 15:36:24 +02:00
OS << " " << PM.ItinsDef->getName() << ",\n";
else
OS << " nullptr, // No Itinerary\n";
if (PM.hasExtraProcessorInfo())
OS << " &" << PM.ModelName << "ExtraInfo,\n";
else
OS << " nullptr // No extra processor descriptor\n";
OS << "};\n";
}
}
//
// EmitSchedModel - Emits all scheduling model tables, folding common patterns.
//
void SubtargetEmitter::EmitSchedModel(raw_ostream &OS) {
OS << "#ifdef DBGFIELD\n"
<< "#error \"<target>GenSubtargetInfo.inc requires a DBGFIELD macro\"\n"
<< "#endif\n"
<< "#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)\n"
<< "#define DBGFIELD(x) x,\n"
<< "#else\n"
<< "#define DBGFIELD(x)\n"
<< "#endif\n";
if (SchedModels.hasItineraries()) {
std::vector<std::vector<InstrItinerary>> ProcItinLists;
// Emit the stage data
EmitStageAndOperandCycleData(OS, ProcItinLists);
EmitItineraries(OS, ProcItinLists);
}
OS << "\n// ===============================================================\n"
<< "// Data tables for the new per-operand machine model.\n";
SchedClassTables SchedTables;
for (const CodeGenProcModel &ProcModel : SchedModels.procModels()) {
GenSchedClassTables(ProcModel, SchedTables);
}
EmitSchedClassTables(SchedTables, OS);
OS << "\n#undef DBGFIELD\n";
// Emit the processor machine model
EmitProcessorModels(OS);
}
static void emitPredicateProlog(const RecordKeeper &Records, raw_ostream &OS) {
std::string Buffer;
raw_string_ostream Stream(Buffer);
// Collect all the PredicateProlog records and print them to the output
// stream.
std::vector<Record *> Prologs =
Records.getAllDerivedDefinitions("PredicateProlog");
llvm::sort(Prologs, LessRecord());
for (Record *P : Prologs)
Stream << P->getValueAsString("Code") << '\n';
Stream.flush();
OS << Buffer;
}
static bool isTruePredicate(const Record *Rec) {
return Rec->isSubClassOf("MCSchedPredicate") &&
Rec->getValueAsDef("Pred")->isSubClassOf("MCTrue");
}
static void emitPredicates(const CodeGenSchedTransition &T,
const CodeGenSchedClass &SC, PredicateExpander &PE,
raw_ostream &OS) {
std::string Buffer;
raw_string_ostream SS(Buffer);
// If not all predicates are MCTrue, then we need an if-stmt.
unsigned NumNonTruePreds =
T.PredTerm.size() - count_if(T.PredTerm, isTruePredicate);
SS.indent(PE.getIndentLevel() * 2);
if (NumNonTruePreds) {
bool FirstNonTruePredicate = true;
SS << "if (";
PE.setIndentLevel(PE.getIndentLevel() + 2);
for (const Record *Rec : T.PredTerm) {
// Skip predicates that evaluate to "true".
if (isTruePredicate(Rec))
continue;
if (FirstNonTruePredicate) {
FirstNonTruePredicate = false;
} else {
SS << "\n";
SS.indent(PE.getIndentLevel() * 2);
SS << "&& ";
}
if (Rec->isSubClassOf("MCSchedPredicate")) {
PE.expandPredicate(SS, Rec->getValueAsDef("Pred"));
continue;
}
// Expand this legacy predicate and wrap it around braces if there is more
// than one predicate to expand.
SS << ((NumNonTruePreds > 1) ? "(" : "")
<< Rec->getValueAsString("Predicate")
<< ((NumNonTruePreds > 1) ? ")" : "");
}
SS << ")\n"; // end of if-stmt
PE.decreaseIndentLevel();
SS.indent(PE.getIndentLevel() * 2);
PE.decreaseIndentLevel();
}
SS << "return " << T.ToClassIdx << "; // " << SC.Name << '\n';
SS.flush();
OS << Buffer;
}
// Used by method `SubtargetEmitter::emitSchedModelHelpersImpl()` to generate
// epilogue code for the auto-generated helper.
static void emitSchedModelHelperEpilogue(raw_ostream &OS,
bool ShouldReturnZero) {
if (ShouldReturnZero) {
OS << " // Don't know how to resolve this scheduling class.\n"
<< " return 0;\n";
return;
}
OS << " report_fatal_error(\"Expected a variant SchedClass\");\n";
}
static bool hasMCSchedPredicates(const CodeGenSchedTransition &T) {
return all_of(T.PredTerm, [](const Record *Rec) {
return Rec->isSubClassOf("MCSchedPredicate");
});
}
static void collectVariantClasses(const CodeGenSchedModels &SchedModels,
IdxVec &VariantClasses,
bool OnlyExpandMCInstPredicates) {
for (const CodeGenSchedClass &SC : SchedModels.schedClasses()) {
// Ignore non-variant scheduling classes.
if (SC.Transitions.empty())
continue;
if (OnlyExpandMCInstPredicates) {
// Ignore this variant scheduling class no transitions use any meaningful
// MCSchedPredicate definitions.
if (!any_of(SC.Transitions, [](const CodeGenSchedTransition &T) {
return hasMCSchedPredicates(T);
}))
continue;
}
VariantClasses.push_back(SC.Index);
}
}
static void collectProcessorIndices(const CodeGenSchedClass &SC,
IdxVec &ProcIndices) {
// A variant scheduling class may define transitions for multiple
// processors. This function identifies wich processors are associated with
// transition rules specified by variant class `SC`.
for (const CodeGenSchedTransition &T : SC.Transitions) {
IdxVec PI;
std::set_union(&T.ProcIndex, &T.ProcIndex + 1, ProcIndices.begin(),
ProcIndices.end(), std::back_inserter(PI));
ProcIndices.swap(PI);
}
}
static bool isAlwaysTrue(const CodeGenSchedTransition &T) {
return llvm::all_of(T.PredTerm,
[](const Record *R) { return isTruePredicate(R); });
}
void SubtargetEmitter::emitSchedModelHelpersImpl(
raw_ostream &OS, bool OnlyExpandMCInstPredicates) {
IdxVec VariantClasses;
collectVariantClasses(SchedModels, VariantClasses,
OnlyExpandMCInstPredicates);
if (VariantClasses.empty()) {
emitSchedModelHelperEpilogue(OS, OnlyExpandMCInstPredicates);
return;
}
// Construct a switch statement where the condition is a check on the
// scheduling class identifier. There is a `case` for every variant class
// defined by the processor models of this target.
// Each `case` implements a number of rules to resolve (i.e. to transition from)
// a variant scheduling class to another scheduling class. Rules are
// described by instances of CodeGenSchedTransition. Note that transitions may
// not be valid for all processors.
OS << " switch (SchedClass) {\n";
for (unsigned VC : VariantClasses) {
IdxVec ProcIndices;
const CodeGenSchedClass &SC = SchedModels.getSchedClass(VC);
collectProcessorIndices(SC, ProcIndices);
OS << " case " << VC << ": // " << SC.Name << '\n';
PredicateExpander PE(Target);
PE.setByRef(false);
PE.setExpandForMC(OnlyExpandMCInstPredicates);
for (unsigned PI : ProcIndices) {
OS << " ";
// Emit a guard on the processor ID.
if (PI != 0) {
OS << (OnlyExpandMCInstPredicates
? "if (CPUID == "
: "if (SchedModel->getProcessorID() == ");
OS << PI << ") ";
OS << "{ // " << (SchedModels.procModelBegin() + PI)->ModelName << '\n';
}
// Now emit transitions associated with processor PI.
const CodeGenSchedTransition *FinalT = nullptr;
for (const CodeGenSchedTransition &T : SC.Transitions) {
if (PI != 0 && T.ProcIndex != PI)
continue;
// Emit only transitions based on MCSchedPredicate, if it's the case.
// At least the transition specified by NoSchedPred is emitted,
// which becomes the default transition for those variants otherwise
// not based on MCSchedPredicate.
// FIXME: preferably, llvm-mca should instead assume a reasonable
// default when a variant transition is not based on MCSchedPredicate
// for a given processor.
if (OnlyExpandMCInstPredicates && !hasMCSchedPredicates(T))
continue;
// If transition is folded to 'return X' it should be the last one.
if (isAlwaysTrue(T)) {
FinalT = &T;
continue;
}
PE.setIndentLevel(3);
emitPredicates(T, SchedModels.getSchedClass(T.ToClassIdx), PE, OS);
}
if (FinalT)
emitPredicates(*FinalT, SchedModels.getSchedClass(FinalT->ToClassIdx),
PE, OS);
OS << " }\n";
if (PI == 0)
break;
}
if (SC.isInferred())
OS << " return " << SC.Index << ";\n";
OS << " break;\n";
}
OS << " };\n";
emitSchedModelHelperEpilogue(OS, OnlyExpandMCInstPredicates);
}
void SubtargetEmitter::EmitSchedModelHelpers(const std::string &ClassName,
raw_ostream &OS) {
OS << "unsigned " << ClassName
<< "\n::resolveSchedClass(unsigned SchedClass, const MachineInstr *MI,"
<< " const TargetSchedModel *SchedModel) const {\n";
// Emit the predicate prolog code.
emitPredicateProlog(Records, OS);
// Emit target predicates.
emitSchedModelHelpersImpl(OS);
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
OS << "} // " << ClassName << "::resolveSchedClass\n\n";
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
OS << "unsigned " << ClassName
<< "\n::resolveVariantSchedClass(unsigned SchedClass, const MCInst *MI,"
<< " const MCInstrInfo *MCII, unsigned CPUID) const {\n"
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
<< " return " << Target << "_MC"
<< "::resolveVariantSchedClassImpl(SchedClass, MI, MCII, CPUID);\n"
[TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions. This patch adds the ability for processor models to describe dependency breaking instructions. Different processors may specify a different set of dependency-breaking instructions. That means, we cannot assume that all processors of the same target would use the same rules to classify dependency breaking instructions. The main goal of this patch is to provide the means to describe dependency breaking instructions directly via tablegen, and have the following TargetSubtargetInfo hooks redefined in overrides by tabegen'd XXXGenSubtargetInfo classes (here, XXX is a Target name). ``` virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const { return false; } virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const { return isZeroIdiom(MI); } ``` An instruction MI is a dependency-breaking instruction if a call to method isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to true. Similarly, an instruction MI is a special case of zero-idiom dependency breaking instruction if a call to STI.isZeroIdiom(MI) returns true. The extra APInt is used for those targets that may want to select which machine operands have their dependency broken (see comments in code). Note that by default, subtargets don't know about the existence of dependency-breaking. In the absence of external information, those method calls would always return false. A new tablegen class named STIPredicate has been added by this patch to let processor models classify instructions that have properties in common. The idea is that, a MCInstrPredicate definition can be used to "generate" an instruction equivalence class, with the idea that instructions of a same class all have a property in common. STIPredicate definitions are essentially a collection of instruction equivalence classes. Also, different processor models can specify a different variant of the same STIPredicate with different rules (i.e. predicates) to classify instructions. Tablegen backends (in this particular case, the SubtargetEmitter) will be able to process STIPredicate definitions, and automatically generate functions in XXXGenSubtargetInfo. This patch introduces two special kind of STIPredicate classes named IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a definition for those in the BtVer2 scheduling model only. This patch supersedes the one committed at r338372 (phabricator review: D49310). The main advantages are: - We can describe subtarget predicates via tablegen using STIPredicates. - We can describe zero-idioms / dep-breaking instructions directly via tablegen in the scheduling models. In future, the STIPredicates framework can be used for solving other problems. Examples of future developments are: - Teach how to identify optimizable register-register moves - Teach how to identify slow LEA instructions (each subtarget defining its own concept of "slow" LEA). - Teach how to identify instructions that have undocumented false dependencies on the output registers on some processors only. It is also (in my opinion) an elegant way to expose knowledge to both external tools like llvm-mca, and codegen passes. For example, machine schedulers in LLVM could reuse that information when internally constructing the data dependency graph for a code region. This new design feature is also an "opt-in" feature. Processor models don't have to use the new STIPredicates. It has all been designed to be as unintrusive as possible. Differential Revision: https://reviews.llvm.org/D52174 llvm-svn: 342555
2018-09-19 17:57:45 +02:00
<< "} // " << ClassName << "::resolveVariantSchedClass\n\n";
STIPredicateExpander PE(Target);
PE.setClassPrefix(ClassName);
PE.setExpandDefinition(true);
PE.setByRef(false);
PE.setIndentLevel(0);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);
}
void SubtargetEmitter::EmitHwModeCheck(const std::string &ClassName,
raw_ostream &OS) {
const CodeGenHwModes &CGH = TGT.getHwModes();
assert(CGH.getNumModeIds() > 0);
if (CGH.getNumModeIds() == 1)
return;
OS << "unsigned " << ClassName << "::getHwMode() const {\n";
for (unsigned M = 1, NumModes = CGH.getNumModeIds(); M != NumModes; ++M) {
const HwMode &HM = CGH.getMode(M);
OS << " if (checkFeatures(\"" << HM.Features
<< "\")) return " << M << ";\n";
}
OS << " return 0;\n}\n";
}
//
// ParseFeaturesFunction - Produces a subtarget specific function for parsing
// the subtarget features string.
//
void SubtargetEmitter::ParseFeaturesFunction(raw_ostream &OS,
unsigned NumFeatures,
unsigned NumProcs) {
std::vector<Record*> Features =
Records.getAllDerivedDefinitions("SubtargetFeature");
llvm::sort(Features, LessRecord());
2011-04-01 03:56:55 +02:00
OS << "// ParseSubtargetFeatures - Parses features string setting specified\n"
<< "// subtarget options.\n"
<< "void llvm::";
OS << Target;
OS << "Subtarget::ParseSubtargetFeatures(StringRef CPU, StringRef TuneCPU, "
<< "StringRef FS) {\n"
<< " LLVM_DEBUG(dbgs() << \"\\nFeatures:\" << FS);\n"
<< " LLVM_DEBUG(dbgs() << \"\\nCPU:\" << CPU);\n"
<< " LLVM_DEBUG(dbgs() << \"\\nTuneCPU:\" << TuneCPU << \"\\n\\n\");\n";
if (Features.empty()) {
OS << "}\n";
return;
}
OS << " InitMCProcessorInfo(CPU, TuneCPU, FS);\n"
<< " const FeatureBitset &Bits = getFeatureBits();\n";
for (Record *R : Features) {
// Next record
StringRef Instance = R->getName();
StringRef Value = R->getValueAsString("Value");
StringRef Attribute = R->getValueAsString("Attribute");
if (Value=="true" || Value=="false")
OS << " if (Bits[" << Target << "::"
<< Instance << "]) "
<< Attribute << " = " << Value << ";\n";
else
OS << " if (Bits[" << Target << "::"
<< Instance << "] && "
<< Attribute << " < " << Value << ") "
<< Attribute << " = " << Value << ";\n";
}
OS << "}\n";
}
void SubtargetEmitter::emitGenMCSubtargetInfo(raw_ostream &OS) {
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
OS << "namespace " << Target << "_MC {\n"
<< "unsigned resolveVariantSchedClassImpl(unsigned SchedClass,\n"
<< " const MCInst *MI, const MCInstrInfo *MCII, unsigned CPUID) {\n";
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
emitSchedModelHelpersImpl(OS, /* OnlyExpandMCPredicates */ true);
OS << "}\n";
OS << "} // end namespace " << Target << "_MC\n\n";
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
OS << "struct " << Target
<< "GenMCSubtargetInfo : public MCSubtargetInfo {\n";
OS << " " << Target << "GenMCSubtargetInfo(const Triple &TT,\n"
<< " StringRef CPU, StringRef TuneCPU, StringRef FS,\n"
<< " ArrayRef<SubtargetFeatureKV> PF,\n"
<< " ArrayRef<SubtargetSubTypeKV> PD,\n"
<< " const MCWriteProcResEntry *WPR,\n"
<< " const MCWriteLatencyEntry *WL,\n"
<< " const MCReadAdvanceEntry *RA, const InstrStage *IS,\n"
<< " const unsigned *OC, const unsigned *FP) :\n"
<< " MCSubtargetInfo(TT, CPU, TuneCPU, FS, PF, PD,\n"
<< " WPR, WL, RA, IS, OC, FP) { }\n\n"
<< " unsigned resolveVariantSchedClass(unsigned SchedClass,\n"
<< " const MCInst *MI, const MCInstrInfo *MCII,\n"
<< " unsigned CPUID) const override {\n"
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
<< " return " << Target << "_MC"
<< "::resolveVariantSchedClassImpl(SchedClass, MI, MCII, CPUID);\n";
OS << " }\n";
if (TGT.getHwModes().getNumModeIds() > 1)
OS << " unsigned getHwMode() const override;\n";
OS << "};\n";
EmitHwModeCheck(Target + "GenMCSubtargetInfo", OS);
}
[TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions. This patch adds the ability for processor models to describe dependency breaking instructions. Different processors may specify a different set of dependency-breaking instructions. That means, we cannot assume that all processors of the same target would use the same rules to classify dependency breaking instructions. The main goal of this patch is to provide the means to describe dependency breaking instructions directly via tablegen, and have the following TargetSubtargetInfo hooks redefined in overrides by tabegen'd XXXGenSubtargetInfo classes (here, XXX is a Target name). ``` virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const { return false; } virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const { return isZeroIdiom(MI); } ``` An instruction MI is a dependency-breaking instruction if a call to method isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to true. Similarly, an instruction MI is a special case of zero-idiom dependency breaking instruction if a call to STI.isZeroIdiom(MI) returns true. The extra APInt is used for those targets that may want to select which machine operands have their dependency broken (see comments in code). Note that by default, subtargets don't know about the existence of dependency-breaking. In the absence of external information, those method calls would always return false. A new tablegen class named STIPredicate has been added by this patch to let processor models classify instructions that have properties in common. The idea is that, a MCInstrPredicate definition can be used to "generate" an instruction equivalence class, with the idea that instructions of a same class all have a property in common. STIPredicate definitions are essentially a collection of instruction equivalence classes. Also, different processor models can specify a different variant of the same STIPredicate with different rules (i.e. predicates) to classify instructions. Tablegen backends (in this particular case, the SubtargetEmitter) will be able to process STIPredicate definitions, and automatically generate functions in XXXGenSubtargetInfo. This patch introduces two special kind of STIPredicate classes named IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a definition for those in the BtVer2 scheduling model only. This patch supersedes the one committed at r338372 (phabricator review: D49310). The main advantages are: - We can describe subtarget predicates via tablegen using STIPredicates. - We can describe zero-idioms / dep-breaking instructions directly via tablegen in the scheduling models. In future, the STIPredicates framework can be used for solving other problems. Examples of future developments are: - Teach how to identify optimizable register-register moves - Teach how to identify slow LEA instructions (each subtarget defining its own concept of "slow" LEA). - Teach how to identify instructions that have undocumented false dependencies on the output registers on some processors only. It is also (in my opinion) an elegant way to expose knowledge to both external tools like llvm-mca, and codegen passes. For example, machine schedulers in LLVM could reuse that information when internally constructing the data dependency graph for a code region. This new design feature is also an "opt-in" feature. Processor models don't have to use the new STIPredicates. It has all been designed to be as unintrusive as possible. Differential Revision: https://reviews.llvm.org/D52174 llvm-svn: 342555
2018-09-19 17:57:45 +02:00
void SubtargetEmitter::EmitMCInstrAnalysisPredicateFunctions(raw_ostream &OS) {
OS << "\n#ifdef GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS\n";
OS << "#undef GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS\n\n";
STIPredicateExpander PE(Target);
PE.setExpandForMC(true);
PE.setByRef(true);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);
OS << "#endif // GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS\n\n";
OS << "\n#ifdef GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS\n";
OS << "#undef GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS\n\n";
std::string ClassPrefix = Target + "MCInstrAnalysis";
PE.setExpandDefinition(true);
PE.setClassPrefix(ClassPrefix);
PE.setIndentLevel(0);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);
OS << "#endif // GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS\n\n";
}
//
// SubtargetEmitter::run - Main subtarget enumeration emitter.
//
void SubtargetEmitter::run(raw_ostream &OS) {
emitSourceFileHeader("Subtarget Enumeration Source Fragment", OS);
OS << "\n#ifdef GET_SUBTARGETINFO_ENUM\n";
OS << "#undef GET_SUBTARGETINFO_ENUM\n\n";
DenseMap<Record *, unsigned> FeatureMap;
OS << "namespace llvm {\n";
Enumeration(OS, FeatureMap);
OS << "} // end namespace llvm\n\n";
OS << "#endif // GET_SUBTARGETINFO_ENUM\n\n";
OS << "\n#ifdef GET_SUBTARGETINFO_MC_DESC\n";
OS << "#undef GET_SUBTARGETINFO_MC_DESC\n\n";
OS << "namespace llvm {\n";
#if 0
OS << "namespace {\n";
#endif
unsigned NumFeatures = FeatureKeyValues(OS, FeatureMap);
OS << "\n";
EmitSchedModel(OS);
OS << "\n";
unsigned NumProcs = CPUKeyValues(OS, FeatureMap);
OS << "\n";
#if 0
OS << "} // end anonymous namespace\n\n";
#endif
// MCInstrInfo initialization routine.
emitGenMCSubtargetInfo(OS);
OS << "\nstatic inline MCSubtargetInfo *create" << Target
<< "MCSubtargetInfoImpl("
<< "const Triple &TT, StringRef CPU, StringRef TuneCPU, StringRef FS) {\n";
OS << " return new " << Target
<< "GenMCSubtargetInfo(TT, CPU, TuneCPU, FS, ";
if (NumFeatures)
OS << Target << "FeatureKV, ";
else
OS << "None, ";
if (NumProcs)
OS << Target << "SubTypeKV, ";
else
OS << "None, ";
OS << '\n'; OS.indent(22);
OS << Target << "WriteProcResTable, "
<< Target << "WriteLatencyTable, "
<< Target << "ReadAdvanceTable, ";
OS << '\n'; OS.indent(22);
if (SchedModels.hasItineraries()) {
OS << Target << "Stages, "
<< Target << "OperandCycles, "
<< Target << "ForwardingPaths";
} else
OS << "nullptr, nullptr, nullptr";
OS << ");\n}\n\n";
OS << "} // end namespace llvm\n\n";
OS << "#endif // GET_SUBTARGETINFO_MC_DESC\n\n";
OS << "\n#ifdef GET_SUBTARGETINFO_TARGET_DESC\n";
OS << "#undef GET_SUBTARGETINFO_TARGET_DESC\n\n";
OS << "#include \"llvm/Support/Debug.h\"\n";
OS << "#include \"llvm/Support/raw_ostream.h\"\n\n";
ParseFeaturesFunction(OS, NumFeatures, NumProcs);
OS << "#endif // GET_SUBTARGETINFO_TARGET_DESC\n\n";
// Create a TargetSubtargetInfo subclass to hide the MC layer initialization.
OS << "\n#ifdef GET_SUBTARGETINFO_HEADER\n";
OS << "#undef GET_SUBTARGETINFO_HEADER\n\n";
std::string ClassName = Target + "GenSubtargetInfo";
OS << "namespace llvm {\n";
OS << "class DFAPacketizer;\n";
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
OS << "namespace " << Target << "_MC {\n"
<< "unsigned resolveVariantSchedClassImpl(unsigned SchedClass,"
<< " const MCInst *MI, const MCInstrInfo *MCII, unsigned CPUID);\n"
<< "} // end namespace " << Target << "_MC\n\n";
OS << "struct " << ClassName << " : public TargetSubtargetInfo {\n"
<< " explicit " << ClassName << "(const Triple &TT, StringRef CPU, "
<< "StringRef TuneCPU, StringRef FS);\n"
<< "public:\n"
<< " unsigned resolveSchedClass(unsigned SchedClass, "
<< " const MachineInstr *DefMI,"
<< " const TargetSchedModel *SchedModel) const override;\n"
[MCSchedule] Add the ability to compute the latency and throughput information for MCInst. This patch extends the MCSchedModel API with new methods that can be used to obtain the latency and reciprocal througput information for an MCInst. Scheduling models have recently gained the ability to resolve variant scheduling classes associated with MCInst objects. Before, models were only able to resolve a variant scheduling class from a MachineInstr object. This patch is mainly required by D47374 to avoid regressing a pair of x86 specific -print-schedule tests for btver2. Patch D47374 introduces a new variant class to teach the btver scheduling model (x86 target) how to correctly compute the latency profile for some zero-idioms using the new scheduling predicates. The new methods added by this patch would be mainly used by llc when flag -print-schedule is specified. In particular, tests that contain inline assembly require that code is parsed at code emission stage into a sequence of MCInst. That forces the print-schedule functionality to query the latency/rthroughput information for MCInst instructions too. If we don't expose this new API, then we lose "-print-schedule" test coverage as soon as variant scheduling classes are added to the x86 models. The tablegen SubtargetEmitter changes teaches how to query latency profile information using a object that derives from TargetSubtargetInfo. Note that this should really have been part of r333286. To avoid code duplication, the logic that "resolves" variant scheduling classes for MCInst, has been moved to a common place in MC. That logic is used by the "resolveVariantSchedClass" methods redefined in override by the tablegen'd GenSubtargetInfo classes. Differential Revision: https://reviews.llvm.org/D47536 llvm-svn: 333650
2018-05-31 15:30:42 +02:00
<< " unsigned resolveVariantSchedClass(unsigned SchedClass,"
<< " const MCInst *MI, const MCInstrInfo *MCII,"
<< " unsigned CPUID) const override;\n"
<< " DFAPacketizer *createDFAPacketizer(const InstrItineraryData *IID)"
<< " const;\n";
if (TGT.getHwModes().getNumModeIds() > 1)
OS << " unsigned getHwMode() const override;\n";
[TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions. This patch adds the ability for processor models to describe dependency breaking instructions. Different processors may specify a different set of dependency-breaking instructions. That means, we cannot assume that all processors of the same target would use the same rules to classify dependency breaking instructions. The main goal of this patch is to provide the means to describe dependency breaking instructions directly via tablegen, and have the following TargetSubtargetInfo hooks redefined in overrides by tabegen'd XXXGenSubtargetInfo classes (here, XXX is a Target name). ``` virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const { return false; } virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const { return isZeroIdiom(MI); } ``` An instruction MI is a dependency-breaking instruction if a call to method isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to true. Similarly, an instruction MI is a special case of zero-idiom dependency breaking instruction if a call to STI.isZeroIdiom(MI) returns true. The extra APInt is used for those targets that may want to select which machine operands have their dependency broken (see comments in code). Note that by default, subtargets don't know about the existence of dependency-breaking. In the absence of external information, those method calls would always return false. A new tablegen class named STIPredicate has been added by this patch to let processor models classify instructions that have properties in common. The idea is that, a MCInstrPredicate definition can be used to "generate" an instruction equivalence class, with the idea that instructions of a same class all have a property in common. STIPredicate definitions are essentially a collection of instruction equivalence classes. Also, different processor models can specify a different variant of the same STIPredicate with different rules (i.e. predicates) to classify instructions. Tablegen backends (in this particular case, the SubtargetEmitter) will be able to process STIPredicate definitions, and automatically generate functions in XXXGenSubtargetInfo. This patch introduces two special kind of STIPredicate classes named IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a definition for those in the BtVer2 scheduling model only. This patch supersedes the one committed at r338372 (phabricator review: D49310). The main advantages are: - We can describe subtarget predicates via tablegen using STIPredicates. - We can describe zero-idioms / dep-breaking instructions directly via tablegen in the scheduling models. In future, the STIPredicates framework can be used for solving other problems. Examples of future developments are: - Teach how to identify optimizable register-register moves - Teach how to identify slow LEA instructions (each subtarget defining its own concept of "slow" LEA). - Teach how to identify instructions that have undocumented false dependencies on the output registers on some processors only. It is also (in my opinion) an elegant way to expose knowledge to both external tools like llvm-mca, and codegen passes. For example, machine schedulers in LLVM could reuse that information when internally constructing the data dependency graph for a code region. This new design feature is also an "opt-in" feature. Processor models don't have to use the new STIPredicates. It has all been designed to be as unintrusive as possible. Differential Revision: https://reviews.llvm.org/D52174 llvm-svn: 342555
2018-09-19 17:57:45 +02:00
STIPredicateExpander PE(Target);
PE.setByRef(false);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);
OS << "};\n"
<< "} // end namespace llvm\n\n";
OS << "#endif // GET_SUBTARGETINFO_HEADER\n\n";
OS << "\n#ifdef GET_SUBTARGETINFO_CTOR\n";
OS << "#undef GET_SUBTARGETINFO_CTOR\n\n";
OS << "#include \"llvm/CodeGen/TargetSchedule.h\"\n\n";
OS << "namespace llvm {\n";
OS << "extern const llvm::SubtargetFeatureKV " << Target << "FeatureKV[];\n";
OS << "extern const llvm::SubtargetSubTypeKV " << Target << "SubTypeKV[];\n";
OS << "extern const llvm::MCWriteProcResEntry "
<< Target << "WriteProcResTable[];\n";
OS << "extern const llvm::MCWriteLatencyEntry "
<< Target << "WriteLatencyTable[];\n";
OS << "extern const llvm::MCReadAdvanceEntry "
<< Target << "ReadAdvanceTable[];\n";
if (SchedModels.hasItineraries()) {
OS << "extern const llvm::InstrStage " << Target << "Stages[];\n";
OS << "extern const unsigned " << Target << "OperandCycles[];\n";
2012-07-07 05:59:48 +02:00
OS << "extern const unsigned " << Target << "ForwardingPaths[];\n";
}
OS << ClassName << "::" << ClassName << "(const Triple &TT, StringRef CPU, "
<< "StringRef TuneCPU, StringRef FS)\n"
<< " : TargetSubtargetInfo(TT, CPU, TuneCPU, FS, ";
if (NumFeatures)
OS << "makeArrayRef(" << Target << "FeatureKV, " << NumFeatures << "), ";
else
OS << "None, ";
if (NumProcs)
OS << "makeArrayRef(" << Target << "SubTypeKV, " << NumProcs << "), ";
else
OS << "None, ";
OS << '\n'; OS.indent(24);
OS << Target << "WriteProcResTable, "
<< Target << "WriteLatencyTable, "
<< Target << "ReadAdvanceTable, ";
OS << '\n'; OS.indent(24);
if (SchedModels.hasItineraries()) {
OS << Target << "Stages, "
<< Target << "OperandCycles, "
<< Target << "ForwardingPaths";
} else
OS << "nullptr, nullptr, nullptr";
OS << ") {}\n\n";
EmitSchedModelHelpers(ClassName, OS);
EmitHwModeCheck(ClassName, OS);
OS << "} // end namespace llvm\n\n";
OS << "#endif // GET_SUBTARGETINFO_CTOR\n\n";
[TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions. This patch adds the ability for processor models to describe dependency breaking instructions. Different processors may specify a different set of dependency-breaking instructions. That means, we cannot assume that all processors of the same target would use the same rules to classify dependency breaking instructions. The main goal of this patch is to provide the means to describe dependency breaking instructions directly via tablegen, and have the following TargetSubtargetInfo hooks redefined in overrides by tabegen'd XXXGenSubtargetInfo classes (here, XXX is a Target name). ``` virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const { return false; } virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const { return isZeroIdiom(MI); } ``` An instruction MI is a dependency-breaking instruction if a call to method isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to true. Similarly, an instruction MI is a special case of zero-idiom dependency breaking instruction if a call to STI.isZeroIdiom(MI) returns true. The extra APInt is used for those targets that may want to select which machine operands have their dependency broken (see comments in code). Note that by default, subtargets don't know about the existence of dependency-breaking. In the absence of external information, those method calls would always return false. A new tablegen class named STIPredicate has been added by this patch to let processor models classify instructions that have properties in common. The idea is that, a MCInstrPredicate definition can be used to "generate" an instruction equivalence class, with the idea that instructions of a same class all have a property in common. STIPredicate definitions are essentially a collection of instruction equivalence classes. Also, different processor models can specify a different variant of the same STIPredicate with different rules (i.e. predicates) to classify instructions. Tablegen backends (in this particular case, the SubtargetEmitter) will be able to process STIPredicate definitions, and automatically generate functions in XXXGenSubtargetInfo. This patch introduces two special kind of STIPredicate classes named IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a definition for those in the BtVer2 scheduling model only. This patch supersedes the one committed at r338372 (phabricator review: D49310). The main advantages are: - We can describe subtarget predicates via tablegen using STIPredicates. - We can describe zero-idioms / dep-breaking instructions directly via tablegen in the scheduling models. In future, the STIPredicates framework can be used for solving other problems. Examples of future developments are: - Teach how to identify optimizable register-register moves - Teach how to identify slow LEA instructions (each subtarget defining its own concept of "slow" LEA). - Teach how to identify instructions that have undocumented false dependencies on the output registers on some processors only. It is also (in my opinion) an elegant way to expose knowledge to both external tools like llvm-mca, and codegen passes. For example, machine schedulers in LLVM could reuse that information when internally constructing the data dependency graph for a code region. This new design feature is also an "opt-in" feature. Processor models don't have to use the new STIPredicates. It has all been designed to be as unintrusive as possible. Differential Revision: https://reviews.llvm.org/D52174 llvm-svn: 342555
2018-09-19 17:57:45 +02:00
EmitMCInstrAnalysisPredicateFunctions(OS);
}
namespace llvm {
void EmitSubtarget(RecordKeeper &RK, raw_ostream &OS) {
CodeGenTarget CGTarget(RK);
SubtargetEmitter(RK, CGTarget).run(OS);
}
} // end namespace llvm