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 "llvm/ADT/StringExtras.h"
17#include "llvm/TableGen/Error.h"
18#include "llvm/TableGen/Record.h"
19
20using namespace llvm;
21
22static bool isIdentChar(char C) {
23  return (C >= 'a' && C <= 'z') ||
24  (C >= 'A' && C <= 'Z') ||
25  (C >= '0' && C <= '9') ||
26  C == '_';
27}
28
29std::string AsmWriterOperand::getCode() const {
30  if (OperandType == isLiteralTextOperand) {
31    if (Str.size() == 1)
32      return "O << '" + Str + "'; ";
33    return "O << \"" + Str + "\"; ";
34  }
35
36  if (OperandType == isLiteralStatementOperand)
37    return Str;
38
39  std::string Result = Str + "(MI";
40  if (MIOpNo != ~0U)
41    Result += ", " + utostr(MIOpNo);
42  if (PassSubtarget)
43    Result += ", STI";
44  Result += ", O";
45  if (!MiModifier.empty())
46    Result += ", \"" + MiModifier + '"';
47  return Result + "); ";
48}
49
50/// ParseAsmString - Parse the specified Instruction's AsmString into this
51/// AsmWriterInst.
52///
53AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI, unsigned Variant,
54                             unsigned PassSubtarget) {
55  this->CGI = &CGI;
56
57  // NOTE: Any extensions to this code need to be mirrored in the
58  // AsmPrinter::printInlineAsm code that executes as compile time (assuming
59  // that inline asm strings should also get the new feature)!
60  std::string AsmString = CGI.FlattenAsmStringVariants(CGI.AsmString, Variant);
61  std::string::size_type LastEmitted = 0;
62  while (LastEmitted != AsmString.size()) {
63    std::string::size_type DollarPos =
64      AsmString.find_first_of("$\\", LastEmitted);
65    if (DollarPos == std::string::npos) DollarPos = AsmString.size();
66
67    // Emit a constant string fragment.
68    if (DollarPos != LastEmitted) {
69      for (; LastEmitted != DollarPos; ++LastEmitted)
70        switch (AsmString[LastEmitted]) {
71          case '\n':
72            AddLiteralString("\\n");
73            break;
74          case '\t':
75            AddLiteralString("\\t");
76            break;
77          case '"':
78            AddLiteralString("\\\"");
79            break;
80          case '\\':
81            AddLiteralString("\\\\");
82            break;
83          default:
84            AddLiteralString(std::string(1, AsmString[LastEmitted]));
85            break;
86        }
87    } else if (AsmString[DollarPos] == '\\') {
88      if (DollarPos+1 != AsmString.size()) {
89        if (AsmString[DollarPos+1] == 'n') {
90          AddLiteralString("\\n");
91        } else if (AsmString[DollarPos+1] == 't') {
92          AddLiteralString("\\t");
93        } else if (std::string("${|}\\").find(AsmString[DollarPos+1])
94                   != std::string::npos) {
95          AddLiteralString(std::string(1, AsmString[DollarPos+1]));
96        } else {
97          PrintFatalError("Non-supported escaped character found in instruction '" +
98            CGI.TheDef->getName() + "'!");
99        }
100        LastEmitted = DollarPos+2;
101        continue;
102      }
103    } else if (DollarPos+1 != AsmString.size() &&
104               AsmString[DollarPos+1] == '$') {
105      AddLiteralString("$");  // "$$" -> $
106      LastEmitted = DollarPos+2;
107    } else {
108      // Get the name of the variable.
109      std::string::size_type VarEnd = DollarPos+1;
110
111      // handle ${foo}bar as $foo by detecting whether the character following
112      // the dollar sign is a curly brace.  If so, advance VarEnd and DollarPos
113      // so the variable name does not contain the leading curly brace.
114      bool hasCurlyBraces = false;
115      if (VarEnd < AsmString.size() && '{' == AsmString[VarEnd]) {
116        hasCurlyBraces = true;
117        ++DollarPos;
118        ++VarEnd;
119      }
120
121      while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
122        ++VarEnd;
123      std::string VarName(AsmString.begin()+DollarPos+1,
124                          AsmString.begin()+VarEnd);
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("Reached end of string before terminating curly brace in '"
137            + CGI.TheDef->getName() + "'");
138
139        // Look for a modifier string.
140        if (AsmString[VarEnd] == ':') {
141          ++VarEnd;
142          if (VarEnd >= AsmString.size())
143            PrintFatalError("Reached end of string before terminating curly brace in '"
144              + CGI.TheDef->getName() + "'");
145
146          unsigned ModifierStart = VarEnd;
147          while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
148            ++VarEnd;
149          Modifier = std::string(AsmString.begin()+ModifierStart,
150                                 AsmString.begin()+VarEnd);
151          if (Modifier.empty())
152            PrintFatalError("Bad operand modifier name in '"+ CGI.TheDef->getName() + "'");
153        }
154
155        if (AsmString[VarEnd] != '}')
156          PrintFatalError("Variable name beginning with '{' did not end with '}' in '"
157            + CGI.TheDef->getName() + "'");
158        ++VarEnd;
159      }
160      if (VarName.empty() && Modifier.empty())
161        PrintFatalError("Stray '$' in '" + CGI.TheDef->getName() +
162          "' asm string, maybe you want $$?");
163
164      if (VarName.empty()) {
165        // Just a modifier, pass this into PrintSpecial.
166        Operands.emplace_back("PrintSpecial", ~0U, ~0U, Modifier,
167                              PassSubtarget);
168      } else {
169        // Otherwise, normal operand.
170        unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
171        CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
172
173        unsigned MIOp = OpInfo.MIOperandNo;
174        Operands.emplace_back(OpInfo.PrinterMethodName, OpNo, MIOp, Modifier,
175                              PassSubtarget);
176      }
177      LastEmitted = VarEnd;
178    }
179  }
180
181  Operands.emplace_back("return;", AsmWriterOperand::isLiteralStatementOperand);
182}
183
184/// MatchesAllButOneOp - If this instruction is exactly identical to the
185/// specified instruction except for one differing operand, return the differing
186/// operand number.  If more than one operand mismatches, return ~1, otherwise
187/// if the instructions are identical return ~0.
188unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other)const{
189  if (Operands.size() != Other.Operands.size()) return ~1;
190
191  unsigned MismatchOperand = ~0U;
192  for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
193    if (Operands[i] != Other.Operands[i]) {
194      if (MismatchOperand != ~0U)  // Already have one mismatch?
195        return ~1U;
196      MismatchOperand = i;
197    }
198  }
199  return MismatchOperand;
200}
201