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
  15 using namespace llvm;
  16
  17 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  18 LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
  19   errs() << getEnumName() << " " << Index << "\n" << *TheDef;
  20 }
  21 #endif
  22
  23 std::vector<std::pair<Record *, SubtargetFeatureInfo>>
  24 SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
  25   std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
  26   std::vector<Record *> AllPredicates =
  27       Records.getAllDerivedDefinitions("Predicate");
  28   for (Record *Pred : AllPredicates) {
  29     // Ignore predicates that are not intended for the assembler.
  30     //
  31     // The "AssemblerMatcherPredicate" string should be promoted to an argument
  32     // if we re-use the machinery for non-assembler purposes in future.
  33     if (!Pred->getValueAsBit("AssemblerMatcherPredicate"))
  34       continue;
  35
  36     if (Pred->getName().empty())
  37       PrintFatalError(Pred->getLoc(), "Predicate has no name!");
  38
  39     // Ignore always true predicates.
  40     if (Pred->getValueAsString("CondString").empty())
  41       continue;
  42
  43     SubtargetFeatures.emplace_back(
  44         Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
  45   }
  46   return SubtargetFeatures;
  47 }
  48
  49 void SubtargetFeatureInfo::emitSubtargetFeatureBitEnumeration(
  50     const SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS,
  51     const std::map<std::string, unsigned> *HwModes) {
  52   OS << "// Bits for subtarget features that participate in "
  53      << "instruction matching.\n";
  54   unsigned Size = SubtargetFeatures.size();
  55   if (HwModes)
  56     Size += HwModes->size();
  57
  58   OS << "enum SubtargetFeatureBits : " << getMinimalTypeForRange(Size)
  59      << " {\n";
  60   for (const auto &SF : SubtargetFeatures) {
  61     const SubtargetFeatureInfo &SFI = SF.second;
  62     OS << "  " << SFI.getEnumBitName() << " = " << SFI.Index << ",\n";
  63   }
  64
  65   if (HwModes) {
  66     unsigned Offset = SubtargetFeatures.size();
  67     for (const auto &M : *HwModes) {
  68       OS << "  Feature_HwMode" << M.second << "Bit = " << (M.second + Offset)
  69          << ",\n";
  70     }
  71   }
  72
  73   OS << "};\n\n";
  74 }
  75
  76 void SubtargetFeatureInfo::emitNameTable(
  77     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
  78   // Need to sort the name table so that lookup by the log of the enum value
  79   // gives the proper name. More specifically, for a feature of value 1<<n,
  80   // SubtargetFeatureNames[n] should be the name of the feature.
  81   uint64_t IndexUB = 0;
  82   for (const auto &SF : SubtargetFeatures)
  83     if (IndexUB <= SF.second.Index)
  84       IndexUB = SF.second.Index+1;
  85
  86   std::vector<std::string> Names;
  87   if (IndexUB > 0)
  88     Names.resize(IndexUB);
  89   for (const auto &SF : SubtargetFeatures)
  90     Names[SF.second.Index] = SF.second.getEnumName();
  91
  92   OS << "static const char *SubtargetFeatureNames[] = {\n";
  93   for (uint64_t I = 0; I < IndexUB; ++I)
  94     OS << "  \"" << Names[I] << "\",\n";
  95
  96   // A small number of targets have no predicates. Null terminate the array to
  97   // avoid a zero-length array.
  98   OS << "  nullptr\n"
  99      << "};\n\n";
 100 }
 101
 102 void SubtargetFeatureInfo::emitComputeAvailableFeatures(
 103     StringRef TargetName, StringRef ClassName, StringRef FuncName,
 104     const SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS,
 105     StringRef ExtraParams, const std::map<std::string, unsigned> *HwModes) {
 106   OS << "PredicateBitset " << ClassName << "::\n"
 107      << FuncName << "(const " << TargetName << "Subtarget *Subtarget";
 108   if (!ExtraParams.empty())
 109     OS << ", " << ExtraParams;
 110   OS << ") const {\n";
 111   OS << "  PredicateBitset Features;\n";
 112   for (const auto &SF : SubtargetFeatures) {
 113     const SubtargetFeatureInfo &SFI = SF.second;
 114     StringRef CondStr = SFI.TheDef->getValueAsString("CondString");
 115     assert(!CondStr.empty() && "true predicate should have been filtered");
 116
 117     OS << "  if (" << CondStr << ")\n";
 118     OS << "    Features.set(" << SFI.getEnumBitName() << ");\n";
 119   }
 120
 121   if (HwModes) {
 122     for (const auto &M : *HwModes) {
 123       OS << "  if (" << M.first << ")\n";
 124       OS << "    Features.set(Feature_HwMode" << M.second << "Bit);\n";
 125     }
 126   }
 127
 128   OS << "  return Features;\n";
 129   OS << "}\n\n";
 130 }
 131
 132 // If ParenIfBinOp is true, print a surrounding () if Val uses && or ||.
 133 static bool emitFeaturesAux(StringRef TargetName, const Init &Val,
 134                             bool ParenIfBinOp, raw_ostream &OS) {
 135   if (auto *D = dyn_cast<DefInit>(&Val)) {
 136     if (!D->getDef()->isSubClassOf("SubtargetFeature"))
 137       return true;
 138     OS << "FB[" << TargetName << "::" << D->getAsString() << "]";
 139     return false;
 140   }
 141   if (auto *D = dyn_cast<DagInit>(&Val)) {
 142     auto *Op = dyn_cast<DefInit>(D->getOperator());
 143     if (!Op)
 144       return true;
 145     StringRef OpName = Op->getDef()->getName();
 146     if (OpName == "not" && D->getNumArgs() == 1) {
 147       OS << '!';
 148       return emitFeaturesAux(TargetName, *D->getArg(0), true, OS);
 149     }
 150     if ((OpName == "any_of" || OpName == "all_of") && D->getNumArgs() > 0) {
 151       bool Paren = D->getNumArgs() > 1 && std::exchange(ParenIfBinOp, true);
 152       if (Paren)
 153         OS << '(';
 154       ListSeparator LS(OpName == "any_of" ? " || " : " && ");
 155       for (auto *Arg : D->getArgs()) {
 156         OS << LS;
 157         if (emitFeaturesAux(TargetName, *Arg, ParenIfBinOp, OS))
 158           return true;
 159       }
 160       if (Paren)
 161         OS << ')';
 162       return false;
 163     }
 164   }
 165   return true;
 166 }
 167
 168 void SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
 169     StringRef TargetName, StringRef ClassName, StringRef FuncName,
 170     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
 171   OS << "FeatureBitset ";
 172   if (!ClassName.empty())
 173     OS << TargetName << ClassName << "::\n";
 174   OS << FuncName << "(const FeatureBitset &FB) ";
 175   if (!ClassName.empty())
 176     OS << "const ";
 177   OS << "{\n";
 178   OS << "  FeatureBitset Features;\n";
 179   for (const auto &SF : SubtargetFeatures) {
 180     const SubtargetFeatureInfo &SFI = SF.second;
 181
 182     OS << "  if (";
 183     emitFeaturesAux(TargetName, *SFI.TheDef->getValueAsDag("AssemblerCondDag"),
 184                     /*ParenIfBinOp=*/false, OS);
 185     OS << ")\n";
 186     OS << "    Features.set(" << SFI.getEnumBitName() << ");\n";
 187   }
 188   OS << "  return Features;\n";
 189   OS << "}\n\n";
 190 }