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