llvm/utils/TableGen/SubtargetFeatureInfo.cpp

   1 //===- SubtargetFeatureInfo.cpp - Helpers for subtarget features ----------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "SubtargetFeatureInfo.h"
  10 #include "Types.h"
  11 #include "llvm/Config/llvm-config.h"
  12 #include "llvm/TableGen/Error.h"
  13 #include "llvm/TableGen/Record.h"
  14 #include <map>
  15
  16 using namespace llvm;
  17
  18 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  19 LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
  20   errs() << getEnumName() << " " << Index << "\n" << *TheDef;
  21 }
  22 #endif
  23
  24 std::vector<std::pair<Record *, SubtargetFeatureInfo>>
  25 SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
  26   std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
  27   std::vector<Record *> AllPredicates =
  28       Records.getAllDerivedDefinitions("Predicate");
  29   for (Record *Pred : AllPredicates) {
  30     // Ignore predicates that are not intended for the assembler.
  31     //
  32     // The "AssemblerMatcherPredicate" string should be promoted to an argument
  33     // if we re-use the machinery for non-assembler purposes in future.
  34     if (!Pred->getValueAsBit("AssemblerMatcherPredicate"))
  35       continue;
  36
  37     if (Pred->getName().empty())
  38       PrintFatalError(Pred->getLoc(), "Predicate has no name!");
  39
  40     // Ignore always true predicates.
  41     if (Pred->getValueAsString("CondString").empty())
  42       continue;
  43
  44     SubtargetFeatures.emplace_back(
  45         Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
  46   }
  47   return SubtargetFeatures;
  48 }
  49
  50 void SubtargetFeatureInfo::emitSubtargetFeatureBitEnumeration(
  51     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
  52   OS << "// Bits for subtarget features that participate in "
  53      << "instruction matching.\n";
  54   OS << "enum SubtargetFeatureBits : "
  55      << getMinimalTypeForRange(SubtargetFeatures.size()) << " {\n";
  56   for (const auto &SF : SubtargetFeatures) {
  57     const SubtargetFeatureInfo &SFI = SF.second;
  58     OS << "  " << SFI.getEnumBitName() << " = " << SFI.Index << ",\n";
  59   }
  60   OS << "};\n\n";
  61 }
  62
  63 void SubtargetFeatureInfo::emitNameTable(
  64     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
  65   // Need to sort the name table so that lookup by the log of the enum value
  66   // gives the proper name. More specifically, for a feature of value 1<<n,
  67   // SubtargetFeatureNames[n] should be the name of the feature.
  68   uint64_t IndexUB = 0;
  69   for (const auto &SF : SubtargetFeatures)
  70     if (IndexUB <= SF.second.Index)
  71       IndexUB = SF.second.Index+1;
  72
  73   std::vector<std::string> Names;
  74   if (IndexUB > 0)
  75     Names.resize(IndexUB);
  76   for (const auto &SF : SubtargetFeatures)
  77     Names[SF.second.Index] = SF.second.getEnumName();
  78
  79   OS << "static const char *SubtargetFeatureNames[] = {\n";
  80   for (uint64_t I = 0; I < IndexUB; ++I)
  81     OS << "  \"" << Names[I] << "\",\n";
  82
  83   // A small number of targets have no predicates. Null terminate the array to
  84   // avoid a zero-length array.
  85   OS << "  nullptr\n"
  86      << "};\n\n";
  87 }
  88
  89 void SubtargetFeatureInfo::emitComputeAvailableFeatures(
  90     StringRef TargetName, StringRef ClassName, StringRef FuncName,
  91     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS,
  92     StringRef ExtraParams) {
  93   OS << "PredicateBitset " << TargetName << ClassName << "::\n"
  94      << FuncName << "(const " << TargetName << "Subtarget *Subtarget";
  95   if (!ExtraParams.empty())
  96     OS << ", " << ExtraParams;
  97   OS << ") const {\n";
  98   OS << "  PredicateBitset Features;\n";
  99   for (const auto &SF : SubtargetFeatures) {
 100     const SubtargetFeatureInfo &SFI = SF.second;
 101     StringRef CondStr = SFI.TheDef->getValueAsString("CondString");
 102     assert(!CondStr.empty() && "true predicate should have been filtered");
 103
 104     OS << "  if (" << CondStr << ")\n";
 105     OS << "    Features.set(" << SFI.getEnumBitName() << ");\n";
 106   }
 107   OS << "  return Features;\n";
 108   OS << "}\n\n";
 109 }
 110
 111 void SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
 112     StringRef TargetName, StringRef ClassName, StringRef FuncName,
 113     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
 114   OS << "FeatureBitset " << TargetName << ClassName << "::\n"
 115      << FuncName << "(const FeatureBitset &FB) const {\n";
 116   OS << "  FeatureBitset Features;\n";
 117   for (const auto &SF : SubtargetFeatures) {
 118     const SubtargetFeatureInfo &SFI = SF.second;
 119
 120     OS << "  if (";
 121
 122     const DagInit *D = SFI.TheDef->getValueAsDag("AssemblerCondDag");
 123     std::string CombineType = D->getOperator()->getAsString();
 124     if (CombineType != "any_of" && CombineType != "all_of")
 125       PrintFatalError(SFI.TheDef->getLoc(), "Invalid AssemblerCondDag!");
 126     if (D->getNumArgs() == 0)
 127       PrintFatalError(SFI.TheDef->getLoc(), "Invalid AssemblerCondDag!");
 128     bool IsOr = CombineType == "any_of";
 129
 130     if (IsOr)
 131       OS << "(";
 132
 133     ListSeparator LS(IsOr ? " || " : " && ");
 134     for (auto *Arg : D->getArgs()) {
 135       OS << LS;
 136       if (auto *NotArg = dyn_cast<DagInit>(Arg)) {
 137         if (NotArg->getOperator()->getAsString() != "not" ||
 138             NotArg->getNumArgs() != 1)
 139           PrintFatalError(SFI.TheDef->getLoc(), "Invalid AssemblerCondDag!");
 140         Arg = NotArg->getArg(0);
 141         OS << "!";
 142       }
 143       if (!isa<DefInit>(Arg) ||
 144           !cast<DefInit>(Arg)->getDef()->isSubClassOf("SubtargetFeature"))
 145         PrintFatalError(SFI.TheDef->getLoc(), "Invalid AssemblerCondDag!");
 146       OS << "FB[" << TargetName << "::" << Arg->getAsString() << "]";
 147     }
 148
 149     if (IsOr)
 150       OS << ")";
 151
 152     OS << ")\n";
 153     OS << "    Features.set(" << SFI.getEnumBitName() << ");\n";
 154   }
 155   OS << "  return Features;\n";
 156   OS << "}\n\n";
 157 }