utils/TableGen/InstrDocsEmitter.cpp

   1 //===- InstrDocsEmitter.cpp - Opcode Documentation Generator --------------===//
   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 // InstrDocsEmitter generates restructured text documentation for the opcodes
  10 // that can be used by MachineInstr. For each opcode, the documentation lists:
  11 // * Opcode name
  12 // * Assembly string
  13 // * Flags (e.g. mayLoad, isBranch, ...)
  14 // * Operands, including type and name
  15 // * Operand constraints
  16 // * Implicit register uses & defs
  17 // * Predicates
  18 //
  19 //===----------------------------------------------------------------------===//
  20
  21 #include "CodeGenDAGPatterns.h"
  22 #include "CodeGenInstruction.h"
  23 #include "CodeGenTarget.h"
  24 #include "TableGenBackends.h"
  25 #include "llvm/TableGen/Record.h"
  26 #include <string>
  27 #include <vector>
  28
  29 using namespace llvm;
  30
  31 namespace llvm {
  32
  33 void writeTitle(StringRef Str, raw_ostream &OS, char Kind = '-') {
  34   OS << std::string(Str.size(), Kind) << "\n" << Str << "\n"
  35      << std::string(Str.size(), Kind) << "\n";
  36 }
  37
  38 void writeHeader(StringRef Str, raw_ostream &OS, char Kind = '-') {
  39   OS << Str << "\n" << std::string(Str.size(), Kind) << "\n";
  40 }
  41
  42 std::string escapeForRST(StringRef Str) {
  43   std::string Result;
  44   Result.reserve(Str.size() + 4);
  45   for (char C : Str) {
  46     switch (C) {
  47     // We want special characters to be shown as their C escape codes.
  48     case '\n': Result += "\\n"; break;
  49     case '\t': Result += "\\t"; break;
  50     // Underscore at the end of a line has a special meaning in rst.
  51     case '_': Result += "\\_"; break;
  52     default: Result += C;
  53     }
  54   }
  55   return Result;
  56 }
  57
  58 void EmitInstrDocs(RecordKeeper &RK, raw_ostream &OS) {
  59   CodeGenDAGPatterns CDP(RK);
  60   CodeGenTarget &Target = CDP.getTargetInfo();
  61   unsigned VariantCount = Target.getAsmParserVariantCount();
  62
  63   // Page title.
  64   std::string Title = Target.getName();
  65   Title += " Instructions";
  66   writeTitle(Title, OS);
  67   OS << "\n";
  68
  69   for (const CodeGenInstruction *II : Target.getInstructionsByEnumValue()) {
  70     Record *Inst = II->TheDef;
  71
  72     // Don't print the target-independent instructions.
  73     if (II->Namespace == "TargetOpcode")
  74       continue;
  75
  76     // Heading (instruction name).
  77     writeHeader(escapeForRST(Inst->getName()), OS, '=');
  78     OS << "\n";
  79
  80     // Assembly string(s).
  81     if (!II->AsmString.empty()) {
  82       for (unsigned VarNum = 0; VarNum < VariantCount; ++VarNum) {
  83         Record *AsmVariant = Target.getAsmParserVariant(VarNum);
  84         OS << "Assembly string";
  85         if (VariantCount != 1)
  86           OS << " (" << AsmVariant->getValueAsString("Name") << ")";
  87         std::string AsmString =
  88             CodeGenInstruction::FlattenAsmStringVariants(II->AsmString, VarNum);
  89         // We trim spaces at each end of the asm string because rst needs the
  90         // formatting backticks to be next to a non-whitespace character.
  91         OS << ": ``" << escapeForRST(StringRef(AsmString).trim(" "))
  92            << "``\n\n";
  93       }
  94     }
  95
  96     // Boolean flags.
  97     std::vector<const char *> FlagStrings;
  98 #define xstr(s) str(s)
  99 #define str(s) #s
 100 #define FLAG(f) if (II->f) { FlagStrings.push_back(str(f)); }
 101     FLAG(isReturn)
 102     FLAG(isEHScopeReturn)
 103     FLAG(isBranch)
 104     FLAG(isIndirectBranch)
 105     FLAG(isCompare)
 106     FLAG(isMoveImm)
 107     FLAG(isBitcast)
 108     FLAG(isSelect)
 109     FLAG(isBarrier)
 110     FLAG(isCall)
 111     FLAG(isAdd)
 112     FLAG(isTrap)
 113     FLAG(canFoldAsLoad)
 114     FLAG(mayLoad)
 115     //FLAG(mayLoad_Unset) // Deliberately omitted.
 116     FLAG(mayStore)
 117     //FLAG(mayStore_Unset) // Deliberately omitted.
 118     FLAG(isPredicable)
 119     FLAG(isConvertibleToThreeAddress)
 120     FLAG(isCommutable)
 121     FLAG(isTerminator)
 122     FLAG(isReMaterializable)
 123     FLAG(hasDelaySlot)
 124     FLAG(usesCustomInserter)
 125     FLAG(hasPostISelHook)
 126     FLAG(hasCtrlDep)
 127     FLAG(isNotDuplicable)
 128     FLAG(hasSideEffects)
 129     //FLAG(hasSideEffects_Unset) // Deliberately omitted.
 130     FLAG(isAsCheapAsAMove)
 131     FLAG(hasExtraSrcRegAllocReq)
 132     FLAG(hasExtraDefRegAllocReq)
 133     FLAG(isCodeGenOnly)
 134     FLAG(isPseudo)
 135     FLAG(isRegSequence)
 136     FLAG(isExtractSubreg)
 137     FLAG(isInsertSubreg)
 138     FLAG(isConvergent)
 139     FLAG(hasNoSchedulingInfo)
 140     FLAG(variadicOpsAreDefs)
 141     if (!FlagStrings.empty()) {
 142       OS << "Flags: ";
 143       bool IsFirst = true;
 144       for (auto FlagString : FlagStrings) {
 145         if (!IsFirst)
 146           OS << ", ";
 147         OS << "``" << FlagString << "``";
 148         IsFirst = false;
 149       }
 150       OS << "\n\n";
 151     }
 152
 153     // Operands.
 154     for (unsigned i = 0; i < II->Operands.size(); ++i) {
 155       bool IsDef = i < II->Operands.NumDefs;
 156       auto Op = II->Operands[i];
 157
 158       if (Op.MINumOperands > 1) {
 159         // This operand corresponds to multiple operands on the
 160         // MachineInstruction, so print all of them, showing the types and
 161         // names of both the compound operand and the basic operands it
 162         // contains.
 163         for (unsigned SubOpIdx = 0; SubOpIdx < Op.MINumOperands; ++SubOpIdx) {
 164           Record *SubRec =
 165               cast<DefInit>(Op.MIOperandInfo->getArg(SubOpIdx))->getDef();
 166           StringRef SubOpName = Op.MIOperandInfo->getArgNameStr(SubOpIdx);
 167           StringRef SubOpTypeName = SubRec->getName();
 168
 169           OS << "* " << (IsDef ? "DEF" : "USE") << " ``" << Op.Rec->getName()
 170              << "/" << SubOpTypeName << ":$" << Op.Name << ".";
 171           // Not all sub-operands are named, make up a name for these.
 172           if (SubOpName.empty())
 173             OS << "anon" << SubOpIdx;
 174           else
 175             OS << SubOpName;
 176           OS << "``\n\n";
 177         }
 178       } else {
 179         // The operand corresponds to only one MachineInstruction operand.
 180         OS << "* " << (IsDef ? "DEF" : "USE") << " ``" << Op.Rec->getName()
 181            << ":$" << Op.Name << "``\n\n";
 182       }
 183     }
 184
 185     // Constraints.
 186     StringRef Constraints = Inst->getValueAsString("Constraints");
 187     if (!Constraints.empty()) {
 188       OS << "Constraints: ``" << Constraints << "``\n\n";
 189     }
 190
 191     // Implicit definitions.
 192     if (!II->ImplicitDefs.empty()) {
 193       OS << "Implicit defs: ";
 194       bool IsFirst = true;
 195       for (Record *Def : II->ImplicitDefs) {
 196         if (!IsFirst)
 197           OS << ", ";
 198         OS << "``" << Def->getName() << "``";
 199         IsFirst = false;
 200       }
 201       OS << "\n\n";
 202     }
 203
 204     // Implicit uses.
 205     if (!II->ImplicitUses.empty()) {
 206       OS << "Implicit uses: ";
 207       bool IsFirst = true;
 208       for (Record *Use : II->ImplicitUses) {
 209         if (!IsFirst)
 210           OS << ", ";
 211         OS << "``" << Use->getName() << "``";
 212         IsFirst = false;
 213       }
 214       OS << "\n\n";
 215     }
 216
 217     // Predicates.
 218     std::vector<Record *> Predicates =
 219         II->TheDef->getValueAsListOfDefs("Predicates");
 220     if (!Predicates.empty()) {
 221       OS << "Predicates: ";
 222       bool IsFirst = true;
 223       for (Record *P : Predicates) {
 224         if (!IsFirst)
 225           OS << ", ";
 226         OS << "``" << P->getName() << "``";
 227         IsFirst = false;
 228       }
 229       OS << "\n\n";
 230     }
 231   }
 232 }
 233
 234 } // end namespace llvm