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     SubtargetFeatures.emplace_back(
  42         Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
  43   }
  44   return SubtargetFeatures;
  45 }
  46
  47 void SubtargetFeatureInfo::emitSubtargetFeatureBitEnumeration(
  48     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
  49   OS << "// Bits for subtarget features that participate in "
  50      << "instruction matching.\n";
  51   OS << "enum SubtargetFeatureBits : "
  52      << getMinimalTypeForRange(SubtargetFeatures.size()) << " {\n";
  53   for (const auto &SF : SubtargetFeatures) {
  54     const SubtargetFeatureInfo &SFI = SF.second;
  55     OS << "  " << SFI.getEnumBitName() << " = " << SFI.Index << ",\n";
  56   }
  57   OS << "};\n\n";
  58 }
  59
  60 void SubtargetFeatureInfo::emitNameTable(
  61     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
  62   // Need to sort the name table so that lookup by the log of the enum value
  63   // gives the proper name. More specifically, for a feature of value 1<<n,
  64   // SubtargetFeatureNames[n] should be the name of the feature.
  65   uint64_t IndexUB = 0;
  66   for (const auto &SF : SubtargetFeatures)
  67     if (IndexUB <= SF.second.Index)
  68       IndexUB = SF.second.Index+1;
  69
  70   std::vector<std::string> Names;
  71   if (IndexUB > 0)
  72     Names.resize(IndexUB);
  73   for (const auto &SF : SubtargetFeatures)
  74     Names[SF.second.Index] = SF.second.getEnumName();
  75
  76   OS << "static const char *SubtargetFeatureNames[] = {\n";
  77   for (uint64_t I = 0; I < IndexUB; ++I)
  78     OS << "  \"" << Names[I] << "\",\n";
  79
  80   // A small number of targets have no predicates. Null terminate the array to
  81   // avoid a zero-length array.
  82   OS << "  nullptr\n"
  83      << "};\n\n";
  84 }
  85
  86 void SubtargetFeatureInfo::emitComputeAvailableFeatures(
  87     StringRef TargetName, StringRef ClassName, StringRef FuncName,
  88     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS,
  89     StringRef ExtraParams) {
  90   OS << "PredicateBitset " << TargetName << ClassName << "::\n"
  91      << FuncName << "(const " << TargetName << "Subtarget *Subtarget";
  92   if (!ExtraParams.empty())
  93     OS << ", " << ExtraParams;
  94   OS << ") const {\n";
  95   OS << "  PredicateBitset Features;\n";
  96   for (const auto &SF : SubtargetFeatures) {
  97     const SubtargetFeatureInfo &SFI = SF.second;
  98
  99     OS << "  if (" << SFI.TheDef->getValueAsString("CondString") << ")\n";
 100     OS << "    Features[" << SFI.getEnumBitName() << "] = 1;\n";
 101   }
 102   OS << "  return Features;\n";
 103   OS << "}\n\n";
 104 }
 105
 106 void SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
 107     StringRef TargetName, StringRef ClassName, StringRef FuncName,
 108     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
 109   OS << "FeatureBitset " << TargetName << ClassName << "::\n"
 110      << FuncName << "(const FeatureBitset& FB) const {\n";
 111   OS << "  FeatureBitset Features;\n";
 112   for (const auto &SF : SubtargetFeatures) {
 113     const SubtargetFeatureInfo &SFI = SF.second;
 114
 115     OS << "  if (";
 116     std::string CondStorage =
 117         SFI.TheDef->getValueAsString("AssemblerCondString");
 118     StringRef Conds = CondStorage;
 119     std::pair<StringRef, StringRef> Comma = Conds.split(',');
 120     bool First = true;
 121     do {
 122       if (!First)
 123         OS << " && ";
 124
 125       bool Neg = false;
 126       StringRef Cond = Comma.first;
 127       if (Cond[0] == '!') {
 128         Neg = true;
 129         Cond = Cond.substr(1);
 130       }
 131
 132       OS << "(";
 133       if (Neg)
 134         OS << "!";
 135       OS << "FB[" << TargetName << "::" << Cond << "])";
 136
 137       if (Comma.second.empty())
 138         break;
 139
 140       First = false;
 141       Comma = Comma.second.split(',');
 142     } while (true);
 143
 144     OS << ")\n";
 145     OS << "    Features[" << SFI.getEnumBitName() << "] = 1;\n";
 146   }
 147   OS << "  return Features;\n";
 148   OS << "}\n\n";
 149 }