llvm/utils/TableGen/AsmWriterInst.cpp

   1 //===- AsmWriterInst.h - Classes encapsulating a printable inst -----------===//
   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 // These classes implement a parser for assembly strings.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "AsmWriterInst.h"
  14 #include "CodeGenTarget.h"
  15 #include "llvm/ADT/StringExtras.h"
  16 #include "llvm/TableGen/Error.h"
  17 #include "llvm/TableGen/Record.h"
  18
  19 using namespace llvm;
  20
  21 static bool isIdentChar(char C) { return isAlnum(C) || C == '_'; }
  22
  23 std::string AsmWriterOperand::getCode(bool PassSubtarget) const {
  24   if (OperandType == isLiteralTextOperand) {
  25     if (Str.size() == 1)
  26       return "O << '" + Str + "';";
  27     return "O << \"" + Str + "\";";
  28   }
  29
  30   if (OperandType == isLiteralStatementOperand)
  31     return Str;
  32
  33   std::string Result = Str + "(MI";
  34   if (PCRel)
  35     Result += ", Address";
  36   if (MIOpNo != ~0U)
  37     Result += ", " + utostr(MIOpNo);
  38   if (PassSubtarget)
  39     Result += ", STI";
  40   Result += ", O";
  41   if (!MiModifier.empty())
  42     Result += ", \"" + MiModifier + '"';
  43   return Result + ");";
  44 }
  45
  46 /// ParseAsmString - Parse the specified Instruction's AsmString into this
  47 /// AsmWriterInst.
  48 ///
  49 AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI, unsigned CGIIndex,
  50                              unsigned Variant)
  51     : CGI(&CGI), CGIIndex(CGIIndex) {
  52
  53   // NOTE: Any extensions to this code need to be mirrored in the
  54   // AsmPrinter::printInlineAsm code that executes as compile time (assuming
  55   // that inline asm strings should also get the new feature)!
  56   std::string AsmString = CGI.FlattenAsmStringVariants(CGI.AsmString, Variant);
  57   std::string::size_type LastEmitted = 0;
  58   while (LastEmitted != AsmString.size()) {
  59     std::string::size_type DollarPos =
  60       AsmString.find_first_of("$\\", LastEmitted);
  61     if (DollarPos == std::string::npos) DollarPos = AsmString.size();
  62
  63     // Emit a constant string fragment.
  64     if (DollarPos != LastEmitted) {
  65       for (; LastEmitted != DollarPos; ++LastEmitted)
  66         switch (AsmString[LastEmitted]) {
  67           case '\n':
  68             AddLiteralString("\\n");
  69             break;
  70           case '\t':
  71             AddLiteralString("\\t");
  72             break;
  73           case '"':
  74             AddLiteralString("\\\"");
  75             break;
  76           case '\\':
  77             AddLiteralString("\\\\");
  78             break;
  79           default:
  80             AddLiteralString(std::string(1, AsmString[LastEmitted]));
  81             break;
  82         }
  83     } else if (AsmString[DollarPos] == '\\') {
  84       if (DollarPos+1 != AsmString.size()) {
  85         if (AsmString[DollarPos+1] == 'n') {
  86           AddLiteralString("\\n");
  87         } else if (AsmString[DollarPos+1] == 't') {
  88           AddLiteralString("\\t");
  89         } else if (std::string("${|}\\").find(AsmString[DollarPos+1])
  90                    != std::string::npos) {
  91           AddLiteralString(std::string(1, AsmString[DollarPos+1]));
  92         } else {
  93           PrintFatalError(
  94               CGI.TheDef->getLoc(),
  95               "Non-supported escaped character found in instruction '" +
  96                   CGI.TheDef->getName() + "'!");
  97         }
  98         LastEmitted = DollarPos+2;
  99         continue;
 100       }
 101     } else if (DollarPos+1 != AsmString.size() &&
 102                AsmString[DollarPos+1] == '$') {
 103       AddLiteralString("$");  // "$$" -> $
 104       LastEmitted = DollarPos+2;
 105     } else {
 106       // Get the name of the variable.
 107       std::string::size_type VarEnd = DollarPos+1;
 108
 109       // handle ${foo}bar as $foo by detecting whether the character following
 110       // the dollar sign is a curly brace.  If so, advance VarEnd and DollarPos
 111       // so the variable name does not contain the leading curly brace.
 112       bool hasCurlyBraces = false;
 113       if (VarEnd < AsmString.size() && '{' == AsmString[VarEnd]) {
 114         hasCurlyBraces = true;
 115         ++DollarPos;
 116         ++VarEnd;
 117       }
 118
 119       while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
 120         ++VarEnd;
 121       StringRef VarName(AsmString.data()+DollarPos+1, VarEnd-DollarPos-1);
 122
 123       // Modifier - Support ${foo:modifier} syntax, where "modifier" is passed
 124       // into printOperand.  Also support ${:feature}, which is passed into
 125       // PrintSpecial.
 126       std::string Modifier;
 127
 128       // In order to avoid starting the next string at the terminating curly
 129       // brace, advance the end position past it if we found an opening curly
 130       // brace.
 131       if (hasCurlyBraces) {
 132         if (VarEnd >= AsmString.size())
 133           PrintFatalError(
 134               CGI.TheDef->getLoc(),
 135               "Reached end of string before terminating curly brace in '" +
 136                   CGI.TheDef->getName() + "'");
 137
 138         // Look for a modifier string.
 139         if (AsmString[VarEnd] == ':') {
 140           ++VarEnd;
 141           if (VarEnd >= AsmString.size())
 142             PrintFatalError(
 143                 CGI.TheDef->getLoc(),
 144                 "Reached end of string before terminating curly brace in '" +
 145                     CGI.TheDef->getName() + "'");
 146
 147           std::string::size_type ModifierStart = VarEnd;
 148           while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
 149             ++VarEnd;
 150           Modifier = std::string(AsmString.begin()+ModifierStart,
 151                                  AsmString.begin()+VarEnd);
 152           if (Modifier.empty())
 153             PrintFatalError(CGI.TheDef->getLoc(),
 154                             "Bad operand modifier name in '" +
 155                                 CGI.TheDef->getName() + "'");
 156         }
 157
 158         if (AsmString[VarEnd] != '}')
 159           PrintFatalError(
 160               CGI.TheDef->getLoc(),
 161               "Variable name beginning with '{' did not end with '}' in '" +
 162                   CGI.TheDef->getName() + "'");
 163         ++VarEnd;
 164       }
 165       if (VarName.empty() && Modifier.empty())
 166         PrintFatalError(CGI.TheDef->getLoc(),
 167                         "Stray '$' in '" + CGI.TheDef->getName() +
 168                             "' asm string, maybe you want $$?");
 169
 170       if (VarName.empty()) {
 171         // Just a modifier, pass this into PrintSpecial.
 172         Operands.emplace_back("PrintSpecial", ~0U, Modifier);
 173       } else {
 174         // Otherwise, normal operand.
 175         unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
 176         CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
 177
 178         unsigned MIOp = OpInfo.MIOperandNo;
 179         Operands.emplace_back(OpInfo.PrinterMethodName, MIOp, Modifier,
 180                               AsmWriterOperand::isMachineInstrOperand,
 181                               OpInfo.OperandType == "MCOI::OPERAND_PCREL");
 182       }
 183       LastEmitted = VarEnd;
 184     }
 185   }
 186
 187   Operands.emplace_back("return;", AsmWriterOperand::isLiteralStatementOperand);
 188 }
 189
 190 /// MatchesAllButOneOp - If this instruction is exactly identical to the
 191 /// specified instruction except for one differing operand, return the differing
 192 /// operand number.  If more than one operand mismatches, return ~1, otherwise
 193 /// if the instructions are identical return ~0.
 194 unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other)const{
 195   if (Operands.size() != Other.Operands.size()) return ~1;
 196
 197   unsigned MismatchOperand = ~0U;
 198   for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
 199     if (Operands[i] != Other.Operands[i]) {
 200       if (MismatchOperand != ~0U)  // Already have one mismatch?
 201         return ~1U;
 202       MismatchOperand = i;
 203     }
 204   }
 205   return MismatchOperand;
 206 }