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) {
  22   return (C >= 'a' && C <= 'z') ||
  23   (C >= 'A' && C <= 'Z') ||
  24   (C >= '0' && C <= '9') ||
  25   C == '_';
  26 }
  27
  28 std::string AsmWriterOperand::getCode(bool PassSubtarget) const {
  29   if (OperandType == isLiteralTextOperand) {
  30     if (Str.size() == 1)
  31       return "O << '" + Str + "';";
  32     return "O << \"" + Str + "\";";
  33   }
  34
  35   if (OperandType == isLiteralStatementOperand)
  36     return Str;
  37
  38   std::string Result = Str + "(MI";
  39   if (MIOpNo != ~0U)
  40     Result += ", " + utostr(MIOpNo);
  41   if (PassSubtarget)
  42     Result += ", STI";
  43   Result += ", O";
  44   if (!MiModifier.empty())
  45     Result += ", \"" + MiModifier + '"';
  46   return Result + ");";
  47 }
  48
  49 /// ParseAsmString - Parse the specified Instruction's AsmString into this
  50 /// AsmWriterInst.
  51 ///
  52 AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI, unsigned CGIIndex,
  53                              unsigned Variant)
  54     : CGI(&CGI), CGIIndex(CGIIndex) {
  55
  56   // NOTE: Any extensions to this code need to be mirrored in the
  57   // AsmPrinter::printInlineAsm code that executes as compile time (assuming
  58   // that inline asm strings should also get the new feature)!
  59   std::string AsmString = CGI.FlattenAsmStringVariants(CGI.AsmString, Variant);
  60   std::string::size_type LastEmitted = 0;
  61   while (LastEmitted != AsmString.size()) {
  62     std::string::size_type DollarPos =
  63       AsmString.find_first_of("$\\", LastEmitted);
  64     if (DollarPos == std::string::npos) DollarPos = AsmString.size();
  65
  66     // Emit a constant string fragment.
  67     if (DollarPos != LastEmitted) {
  68       for (; LastEmitted != DollarPos; ++LastEmitted)
  69         switch (AsmString[LastEmitted]) {
  70           case '\n':
  71             AddLiteralString("\\n");
  72             break;
  73           case '\t':
  74             AddLiteralString("\\t");
  75             break;
  76           case '"':
  77             AddLiteralString("\\\"");
  78             break;
  79           case '\\':
  80             AddLiteralString("\\\\");
  81             break;
  82           default:
  83             AddLiteralString(std::string(1, AsmString[LastEmitted]));
  84             break;
  85         }
  86     } else if (AsmString[DollarPos] == '\\') {
  87       if (DollarPos+1 != AsmString.size()) {
  88         if (AsmString[DollarPos+1] == 'n') {
  89           AddLiteralString("\\n");
  90         } else if (AsmString[DollarPos+1] == 't') {
  91           AddLiteralString("\\t");
  92         } else if (std::string("${|}\\").find(AsmString[DollarPos+1])
  93                    != std::string::npos) {
  94           AddLiteralString(std::string(1, AsmString[DollarPos+1]));
  95         } else {
  96           PrintFatalError(
  97               CGI.TheDef->getLoc(),
  98               "Non-supported escaped character found in instruction '" +
  99                   CGI.TheDef->getName() + "'!");
 100         }
 101         LastEmitted = DollarPos+2;
 102         continue;
 103       }
 104     } else if (DollarPos+1 != AsmString.size() &&
 105                AsmString[DollarPos+1] == '$') {
 106       AddLiteralString("$");  // "$$" -> $
 107       LastEmitted = DollarPos+2;
 108     } else {
 109       // Get the name of the variable.
 110       std::string::size_type VarEnd = DollarPos+1;
 111
 112       // handle ${foo}bar as $foo by detecting whether the character following
 113       // the dollar sign is a curly brace.  If so, advance VarEnd and DollarPos
 114       // so the variable name does not contain the leading curly brace.
 115       bool hasCurlyBraces = false;
 116       if (VarEnd < AsmString.size() && '{' == AsmString[VarEnd]) {
 117         hasCurlyBraces = true;
 118         ++DollarPos;
 119         ++VarEnd;
 120       }
 121
 122       while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
 123         ++VarEnd;
 124       StringRef VarName(AsmString.data()+DollarPos+1, VarEnd-DollarPos-1);
 125
 126       // Modifier - Support ${foo:modifier} syntax, where "modifier" is passed
 127       // into printOperand.  Also support ${:feature}, which is passed into
 128       // PrintSpecial.
 129       std::string Modifier;
 130
 131       // In order to avoid starting the next string at the terminating curly
 132       // brace, advance the end position past it if we found an opening curly
 133       // brace.
 134       if (hasCurlyBraces) {
 135         if (VarEnd >= AsmString.size())
 136           PrintFatalError(
 137               CGI.TheDef->getLoc(),
 138               "Reached end of string before terminating curly brace in '" +
 139                   CGI.TheDef->getName() + "'");
 140
 141         // Look for a modifier string.
 142         if (AsmString[VarEnd] == ':') {
 143           ++VarEnd;
 144           if (VarEnd >= AsmString.size())
 145             PrintFatalError(
 146                 CGI.TheDef->getLoc(),
 147                 "Reached end of string before terminating curly brace in '" +
 148                     CGI.TheDef->getName() + "'");
 149
 150           std::string::size_type ModifierStart = VarEnd;
 151           while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
 152             ++VarEnd;
 153           Modifier = std::string(AsmString.begin()+ModifierStart,
 154                                  AsmString.begin()+VarEnd);
 155           if (Modifier.empty())
 156             PrintFatalError(CGI.TheDef->getLoc(),
 157                             "Bad operand modifier name in '" +
 158                                 CGI.TheDef->getName() + "'");
 159         }
 160
 161         if (AsmString[VarEnd] != '}')
 162           PrintFatalError(
 163               CGI.TheDef->getLoc(),
 164               "Variable name beginning with '{' did not end with '}' in '" +
 165                   CGI.TheDef->getName() + "'");
 166         ++VarEnd;
 167       }
 168       if (VarName.empty() && Modifier.empty())
 169         PrintFatalError(CGI.TheDef->getLoc(),
 170                         "Stray '$' in '" + CGI.TheDef->getName() +
 171                             "' asm string, maybe you want $$?");
 172
 173       if (VarName.empty()) {
 174         // Just a modifier, pass this into PrintSpecial.
 175         Operands.emplace_back("PrintSpecial", ~0U, Modifier);
 176       } else {
 177         // Otherwise, normal operand.
 178         unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
 179         CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
 180
 181         unsigned MIOp = OpInfo.MIOperandNo;
 182         Operands.emplace_back(OpInfo.PrinterMethodName, MIOp, Modifier);
 183       }
 184       LastEmitted = VarEnd;
 185     }
 186   }
 187
 188   Operands.emplace_back("return;", AsmWriterOperand::isLiteralStatementOperand);
 189 }
 190
 191 /// MatchesAllButOneOp - If this instruction is exactly identical to the
 192 /// specified instruction except for one differing operand, return the differing
 193 /// operand number.  If more than one operand mismatches, return ~1, otherwise
 194 /// if the instructions are identical return ~0.
 195 unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other)const{
 196   if (Operands.size() != Other.Operands.size()) return ~1;
 197
 198   unsigned MismatchOperand = ~0U;
 199   for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
 200     if (Operands[i] != Other.Operands[i]) {
 201       if (MismatchOperand != ~0U)  // Already have one mismatch?
 202         return ~1U;
 203       MismatchOperand = i;
 204     }
 205   }
 206   return MismatchOperand;
 207 }