freebsd-dev/contrib/llvm/utils/TableGen/RegisterBankEmitter.cpp
2017-07-13 21:58:45 +00:00

321 lines
12 KiB
C++

//===- RegisterBankEmitter.cpp - Generate a Register Bank Desc. -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend is responsible for emitting a description of a target
// register bank for a code generator.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/BitVector.h"
#include "llvm/Support/Debug.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
#include "CodeGenRegisters.h"
#define DEBUG_TYPE "register-bank-emitter"
using namespace llvm;
namespace {
class RegisterBank {
/// A vector of register classes that are included in the register bank.
typedef std::vector<const CodeGenRegisterClass *> RegisterClassesTy;
private:
const Record &TheDef;
/// The register classes that are covered by the register bank.
RegisterClassesTy RCs;
/// The register class with the largest register size.
const CodeGenRegisterClass *RCWithLargestRegsSize;
public:
RegisterBank(const Record &TheDef)
: TheDef(TheDef), RCs(), RCWithLargestRegsSize(nullptr) {}
/// Get the human-readable name for the bank.
StringRef getName() const { return TheDef.getValueAsString("Name"); }
/// Get the name of the enumerator in the ID enumeration.
std::string getEnumeratorName() const { return (TheDef.getName() + "ID").str(); }
/// Get the name of the array holding the register class coverage data;
std::string getCoverageArrayName() const {
return (TheDef.getName() + "CoverageData").str();
}
/// Get the name of the global instance variable.
StringRef getInstanceVarName() const { return TheDef.getName(); }
const Record &getDef() const { return TheDef; }
/// Get the register classes listed in the RegisterBank.RegisterClasses field.
std::vector<const CodeGenRegisterClass *>
getExplictlySpecifiedRegisterClasses(
CodeGenRegBank &RegisterClassHierarchy) const {
std::vector<const CodeGenRegisterClass *> RCs;
for (const auto &RCDef : getDef().getValueAsListOfDefs("RegisterClasses"))
RCs.push_back(RegisterClassHierarchy.getRegClass(RCDef));
return RCs;
}
/// Add a register class to the bank without duplicates.
void addRegisterClass(const CodeGenRegisterClass *RC) {
if (std::find_if(RCs.begin(), RCs.end(),
[&RC](const CodeGenRegisterClass *X) {
return X == RC;
}) != RCs.end())
return;
// FIXME? We really want the register size rather than the spill size
// since the spill size may be bigger on some targets with
// limited load/store instructions. However, we don't store the
// register size anywhere (we could sum the sizes of the subregisters
// but there may be additional bits too) and we can't derive it from
// the VT's reliably due to Untyped.
if (RCWithLargestRegsSize == nullptr)
RCWithLargestRegsSize = RC;
else if (RCWithLargestRegsSize->SpillSize < RC->SpillSize)
RCWithLargestRegsSize = RC;
assert(RCWithLargestRegsSize && "RC was nullptr?");
RCs.emplace_back(RC);
}
const CodeGenRegisterClass *getRCWithLargestRegsSize() const {
return RCWithLargestRegsSize;
}
iterator_range<typename RegisterClassesTy::const_iterator>
register_classes() const {
return llvm::make_range(RCs.begin(), RCs.end());
}
};
class RegisterBankEmitter {
private:
RecordKeeper &Records;
CodeGenRegBank RegisterClassHierarchy;
void emitHeader(raw_ostream &OS, const StringRef TargetName,
const std::vector<RegisterBank> &Banks);
void emitBaseClassDefinition(raw_ostream &OS, const StringRef TargetName,
const std::vector<RegisterBank> &Banks);
void emitBaseClassImplementation(raw_ostream &OS, const StringRef TargetName,
std::vector<RegisterBank> &Banks);
public:
RegisterBankEmitter(RecordKeeper &R)
: Records(R), RegisterClassHierarchy(Records) {}
void run(raw_ostream &OS);
};
} // end anonymous namespace
/// Emit code to declare the ID enumeration and external global instance
/// variables.
void RegisterBankEmitter::emitHeader(raw_ostream &OS,
const StringRef TargetName,
const std::vector<RegisterBank> &Banks) {
// <Target>RegisterBankInfo.h
OS << "namespace llvm {\n"
<< "namespace " << TargetName << " {\n"
<< "enum {\n";
for (const auto &Bank : Banks)
OS << " " << Bank.getEnumeratorName() << ",\n";
OS << " NumRegisterBanks,\n"
<< "};\n"
<< "} // end namespace " << TargetName << "\n"
<< "} // end namespace llvm\n";
}
/// Emit declarations of the <Target>GenRegisterBankInfo class.
void RegisterBankEmitter::emitBaseClassDefinition(
raw_ostream &OS, const StringRef TargetName,
const std::vector<RegisterBank> &Banks) {
OS << "private:\n"
<< " static RegisterBank *RegBanks[];\n\n"
<< "protected:\n"
<< " " << TargetName << "GenRegisterBankInfo();\n"
<< "\n";
}
/// Visit each register class belonging to the given register bank.
///
/// A class belongs to the bank iff any of these apply:
/// * It is explicitly specified
/// * It is a subclass of a class that is a member.
/// * It is a class containing subregisters of the registers of a class that
/// is a member. This is known as a subreg-class.
///
/// This function must be called for each explicitly specified register class.
///
/// \param RC The register class to search.
/// \param Kind A debug string containing the path the visitor took to reach RC.
/// \param VisitFn The action to take for each class visited. It may be called
/// multiple times for a given class if there are multiple paths
/// to the class.
static void visitRegisterBankClasses(
CodeGenRegBank &RegisterClassHierarchy, const CodeGenRegisterClass *RC,
const Twine Kind,
std::function<void(const CodeGenRegisterClass *, StringRef)> VisitFn,
SmallPtrSetImpl<const CodeGenRegisterClass *> &VisitedRCs) {
// Make sure we only visit each class once to avoid infinite loops.
if (VisitedRCs.count(RC))
return;
VisitedRCs.insert(RC);
// Visit each explicitly named class.
VisitFn(RC, Kind.str());
for (const auto &PossibleSubclass : RegisterClassHierarchy.getRegClasses()) {
std::string TmpKind =
(Twine(Kind) + " (" + PossibleSubclass.getName() + ")").str();
// Visit each subclass of an explicitly named class.
if (RC != &PossibleSubclass && RC->hasSubClass(&PossibleSubclass))
visitRegisterBankClasses(RegisterClassHierarchy, &PossibleSubclass,
TmpKind + " " + RC->getName() + " subclass",
VisitFn, VisitedRCs);
// Visit each class that contains only subregisters of RC with a common
// subregister-index.
//
// More precisely, PossibleSubclass is a subreg-class iff Reg:SubIdx is in
// PossibleSubclass for all registers Reg from RC using any
// subregister-index SubReg
for (const auto &SubIdx : RegisterClassHierarchy.getSubRegIndices()) {
BitVector BV(RegisterClassHierarchy.getRegClasses().size());
PossibleSubclass.getSuperRegClasses(&SubIdx, BV);
if (BV.test(RC->EnumValue)) {
std::string TmpKind2 = (Twine(TmpKind) + " " + RC->getName() +
" class-with-subregs: " + RC->getName())
.str();
VisitFn(&PossibleSubclass, TmpKind2);
}
}
}
}
void RegisterBankEmitter::emitBaseClassImplementation(
raw_ostream &OS, StringRef TargetName,
std::vector<RegisterBank> &Banks) {
OS << "namespace llvm {\n"
<< "namespace " << TargetName << " {\n";
for (const auto &Bank : Banks) {
std::vector<std::vector<const CodeGenRegisterClass *>> RCsGroupedByWord(
(RegisterClassHierarchy.getRegClasses().size() + 31) / 32);
for (const auto &RC : Bank.register_classes())
RCsGroupedByWord[RC->EnumValue / 32].push_back(RC);
OS << "const uint32_t " << Bank.getCoverageArrayName() << "[] = {\n";
unsigned LowestIdxInWord = 0;
for (const auto &RCs : RCsGroupedByWord) {
OS << " // " << LowestIdxInWord << "-" << (LowestIdxInWord + 31) << "\n";
for (const auto &RC : RCs) {
std::string QualifiedRegClassID =
(Twine(RC->Namespace) + "::" + RC->getName() + "RegClassID").str();
OS << " (1u << (" << QualifiedRegClassID << " - "
<< LowestIdxInWord << ")) |\n";
}
OS << " 0,\n";
LowestIdxInWord += 32;
}
OS << "};\n";
}
OS << "\n";
for (const auto &Bank : Banks) {
std::string QualifiedBankID =
(TargetName + "::" + Bank.getEnumeratorName()).str();
unsigned Size = Bank.getRCWithLargestRegsSize()->SpillSize;
OS << "RegisterBank " << Bank.getInstanceVarName() << "(/* ID */ "
<< QualifiedBankID << ", /* Name */ \"" << Bank.getName()
<< "\", /* Size */ " << Size << ", "
<< "/* CoveredRegClasses */ " << Bank.getCoverageArrayName()
<< ", /* NumRegClasses */ "
<< RegisterClassHierarchy.getRegClasses().size() << ");\n";
}
OS << "} // end namespace " << TargetName << "\n"
<< "\n";
OS << "RegisterBank *" << TargetName
<< "GenRegisterBankInfo::RegBanks[] = {\n";
for (const auto &Bank : Banks)
OS << " &" << TargetName << "::" << Bank.getInstanceVarName() << ",\n";
OS << "};\n\n";
OS << TargetName << "GenRegisterBankInfo::" << TargetName
<< "GenRegisterBankInfo()\n"
<< " : RegisterBankInfo(RegBanks, " << TargetName
<< "::NumRegisterBanks) {\n"
<< " // Assert that RegBank indices match their ID's\n"
<< "#ifndef NDEBUG\n"
<< " unsigned Index = 0;\n"
<< " for (const auto &RB : RegBanks)\n"
<< " assert(Index++ == RB->getID() && \"Index != ID\");\n"
<< "#endif // NDEBUG\n"
<< "}\n"
<< "} // end namespace llvm\n";
}
void RegisterBankEmitter::run(raw_ostream &OS) {
std::vector<Record*> Targets = Records.getAllDerivedDefinitions("Target");
if (Targets.size() != 1)
PrintFatalError("ERROR: Too many or too few subclasses of Target defined!");
StringRef TargetName = Targets[0]->getName();
std::vector<RegisterBank> Banks;
for (const auto &V : Records.getAllDerivedDefinitions("RegisterBank")) {
SmallPtrSet<const CodeGenRegisterClass *, 8> VisitedRCs;
RegisterBank Bank(*V);
for (const CodeGenRegisterClass *RC :
Bank.getExplictlySpecifiedRegisterClasses(RegisterClassHierarchy)) {
visitRegisterBankClasses(
RegisterClassHierarchy, RC, "explicit",
[&Bank](const CodeGenRegisterClass *RC, StringRef Kind) {
DEBUG(dbgs() << "Added " << RC->getName() << "(" << Kind << ")\n");
Bank.addRegisterClass(RC);
}, VisitedRCs);
}
Banks.push_back(Bank);
}
emitSourceFileHeader("Register Bank Source Fragments", OS);
OS << "#ifdef GET_REGBANK_DECLARATIONS\n"
<< "#undef GET_REGBANK_DECLARATIONS\n";
emitHeader(OS, TargetName, Banks);
OS << "#endif // GET_REGBANK_DECLARATIONS\n\n"
<< "#ifdef GET_TARGET_REGBANK_CLASS\n"
<< "#undef GET_TARGET_REGBANK_CLASS\n";
emitBaseClassDefinition(OS, TargetName, Banks);
OS << "#endif // GET_TARGET_REGBANK_CLASS\n\n"
<< "#ifdef GET_TARGET_REGBANK_IMPL\n"
<< "#undef GET_TARGET_REGBANK_IMPL\n";
emitBaseClassImplementation(OS, TargetName, Banks);
OS << "#endif // GET_TARGET_REGBANK_IMPL\n";
}
namespace llvm {
void EmitRegisterBank(RecordKeeper &RK, raw_ostream &OS) {
RegisterBankEmitter(RK).run(OS);
}
} // end namespace llvm