utils/TableGen/AsmWriterInst.cpp

   1 //===- AsmWriterInst.h - Classes encapsulating a printable inst -----------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // These classes implement a parser for assembly strings.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "AsmWriterInst.h"
  15 #include "CodeGenTarget.h"
  16 #include "Record.h"
  17 #include "llvm/ADT/StringExtras.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() 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   Result += ", O";
  42   if (!MiModifier.empty())
  43     Result += ", \"" + MiModifier + '"';
  44   return Result + "); ";
  45 }
  46
  47 /// ParseAsmString - Parse the specified Instruction's AsmString into this
  48 /// AsmWriterInst.
  49 ///
  50 AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI,
  51                              unsigned Variant,
  52                              int FirstOperandColumn,
  53                              int OperandSpacing) {
  54   this->CGI = &CGI;
  55
  56   // This is the number of tabs we've seen if we're doing columnar layout.
  57   unsigned CurColumn = 0;
  58
  59
  60   // NOTE: Any extensions to this code need to be mirrored in the
  61   // AsmPrinter::printInlineAsm code that executes as compile time (assuming
  62   // that inline asm strings should also get the new feature)!
  63   std::string AsmString = CGI.FlattenAsmStringVariants(CGI.AsmString, Variant);
  64   std::string::size_type LastEmitted = 0;
  65   while (LastEmitted != AsmString.size()) {
  66     std::string::size_type DollarPos =
  67       AsmString.find_first_of("$\\", LastEmitted);
  68     if (DollarPos == std::string::npos) DollarPos = AsmString.size();
  69
  70     // Emit a constant string fragment.
  71     if (DollarPos != LastEmitted) {
  72       for (; LastEmitted != DollarPos; ++LastEmitted)
  73         switch (AsmString[LastEmitted]) {
  74           case '\n':
  75             AddLiteralString("\\n");
  76             break;
  77           case '\t':
  78             // If the asm writer is not using a columnar layout, \t is not
  79             // magic.
  80             if (FirstOperandColumn == -1 || OperandSpacing == -1) {
  81               AddLiteralString("\\t");
  82             } else {
  83               // We recognize a tab as an operand delimeter.
  84               unsigned DestColumn = FirstOperandColumn +
  85               CurColumn++ * OperandSpacing;
  86               Operands.push_back(
  87                 AsmWriterOperand(
  88                   "O.PadToColumn(" +
  89                   utostr(DestColumn) + ");\n",
  90                   AsmWriterOperand::isLiteralStatementOperand));
  91             }
  92             break;
  93           case '"':
  94             AddLiteralString("\\\"");
  95             break;
  96           case '\\':
  97             AddLiteralString("\\\\");
  98             break;
  99           default:
 100             AddLiteralString(std::string(1, AsmString[LastEmitted]));
 101             break;
 102         }
 103     } else if (AsmString[DollarPos] == '\\') {
 104       if (DollarPos+1 != AsmString.size()) {
 105         if (AsmString[DollarPos+1] == 'n') {
 106           AddLiteralString("\\n");
 107         } else if (AsmString[DollarPos+1] == 't') {
 108           // If the asm writer is not using a columnar layout, \t is not
 109           // magic.
 110           if (FirstOperandColumn == -1 || OperandSpacing == -1) {
 111             AddLiteralString("\\t");
 112             break;
 113           }
 114
 115           // We recognize a tab as an operand delimeter.
 116           unsigned DestColumn = FirstOperandColumn +
 117           CurColumn++ * OperandSpacing;
 118           Operands.push_back(
 119             AsmWriterOperand("O.PadToColumn(" + utostr(DestColumn) + ");\n",
 120                              AsmWriterOperand::isLiteralStatementOperand));
 121           break;
 122         } else if (std::string("${|}\\").find(AsmString[DollarPos+1])
 123                    != std::string::npos) {
 124           AddLiteralString(std::string(1, AsmString[DollarPos+1]));
 125         } else {
 126           throw "Non-supported escaped character found in instruction '" +
 127           CGI.TheDef->getName() + "'!";
 128         }
 129         LastEmitted = DollarPos+2;
 130         continue;
 131       }
 132     } else if (DollarPos+1 != AsmString.size() &&
 133                AsmString[DollarPos+1] == '$') {
 134       AddLiteralString("$");  // "$$" -> $
 135       LastEmitted = DollarPos+2;
 136     } else {
 137       // Get the name of the variable.
 138       std::string::size_type VarEnd = DollarPos+1;
 139
 140       // handle ${foo}bar as $foo by detecting whether the character following
 141       // the dollar sign is a curly brace.  If so, advance VarEnd and DollarPos
 142       // so the variable name does not contain the leading curly brace.
 143       bool hasCurlyBraces = false;
 144       if (VarEnd < AsmString.size() && '{' == AsmString[VarEnd]) {
 145         hasCurlyBraces = true;
 146         ++DollarPos;
 147         ++VarEnd;
 148       }
 149
 150       while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
 151         ++VarEnd;
 152       std::string VarName(AsmString.begin()+DollarPos+1,
 153                           AsmString.begin()+VarEnd);
 154
 155       // Modifier - Support ${foo:modifier} syntax, where "modifier" is passed
 156       // into printOperand.  Also support ${:feature}, which is passed into
 157       // PrintSpecial.
 158       std::string Modifier;
 159
 160       // In order to avoid starting the next string at the terminating curly
 161       // brace, advance the end position past it if we found an opening curly
 162       // brace.
 163       if (hasCurlyBraces) {
 164         if (VarEnd >= AsmString.size())
 165           throw "Reached end of string before terminating curly brace in '"
 166           + CGI.TheDef->getName() + "'";
 167
 168         // Look for a modifier string.
 169         if (AsmString[VarEnd] == ':') {
 170           ++VarEnd;
 171           if (VarEnd >= AsmString.size())
 172             throw "Reached end of string before terminating curly brace in '"
 173             + CGI.TheDef->getName() + "'";
 174
 175           unsigned ModifierStart = VarEnd;
 176           while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
 177             ++VarEnd;
 178           Modifier = std::string(AsmString.begin()+ModifierStart,
 179                                  AsmString.begin()+VarEnd);
 180           if (Modifier.empty())
 181             throw "Bad operand modifier name in '"+ CGI.TheDef->getName() + "'";
 182         }
 183
 184         if (AsmString[VarEnd] != '}')
 185           throw "Variable name beginning with '{' did not end with '}' in '"
 186           + CGI.TheDef->getName() + "'";
 187         ++VarEnd;
 188       }
 189       if (VarName.empty() && Modifier.empty())
 190         throw "Stray '$' in '" + CGI.TheDef->getName() +
 191         "' asm string, maybe you want $$?";
 192
 193       if (VarName.empty()) {
 194         // Just a modifier, pass this into PrintSpecial.
 195         Operands.push_back(AsmWriterOperand("PrintSpecial",
 196                                             ~0U,
 197                                             ~0U,
 198                                             Modifier));
 199       } else {
 200         // Otherwise, normal operand.
 201         unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
 202         CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
 203
 204         unsigned MIOp = OpInfo.MIOperandNo;
 205         Operands.push_back(AsmWriterOperand(OpInfo.PrinterMethodName,
 206                                             OpNo, MIOp, Modifier));
 207       }
 208       LastEmitted = VarEnd;
 209     }
 210   }
 211
 212   Operands.push_back(AsmWriterOperand("return;",
 213     AsmWriterOperand::isLiteralStatementOperand));
 214 }
 215
 216 /// MatchesAllButOneOp - If this instruction is exactly identical to the
 217 /// specified instruction except for one differing operand, return the differing
 218 /// operand number.  If more than one operand mismatches, return ~1, otherwise
 219 /// if the instructions are identical return ~0.
 220 unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other)const{
 221   if (Operands.size() != Other.Operands.size()) return ~1;
 222
 223   unsigned MismatchOperand = ~0U;
 224   for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
 225     if (Operands[i] != Other.Operands[i]) {
 226       if (MismatchOperand != ~0U)  // Already have one mismatch?
 227         return ~1U;
 228       else
 229         MismatchOperand = i;
 230     }
 231   }
 232   return MismatchOperand;
 233 }