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  Result += ", O";
43  if (!MiModifier.empty())
44    Result += ", \"" + MiModifier + '"';
45  return Result + "); ";
46}
47
48/// ParseAsmString - Parse the specified Instruction's AsmString into this
49/// AsmWriterInst.
50///
51AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI,
52                             unsigned Variant,
53                             int OperandSpacing) {
54  this->CGI = &CGI;
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("Non-supported escaped character found in instruction '" +
97            CGI.TheDef->getName() + "'!");
98        }
99        LastEmitted = DollarPos+2;
100        continue;
101      }
102    } else if (DollarPos+1 != AsmString.size() &&
103               AsmString[DollarPos+1] == '$') {
104      AddLiteralString("$");  // "$$" -> $
105      LastEmitted = DollarPos+2;
106    } else {
107      // Get the name of the variable.
108      std::string::size_type VarEnd = DollarPos+1;
109
110      // handle ${foo}bar as $foo by detecting whether the character following
111      // the dollar sign is a curly brace.  If so, advance VarEnd and DollarPos
112      // so the variable name does not contain the leading curly brace.
113      bool hasCurlyBraces = false;
114      if (VarEnd < AsmString.size() && '{' == AsmString[VarEnd]) {
115        hasCurlyBraces = true;
116        ++DollarPos;
117        ++VarEnd;
118      }
119
120      while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
121        ++VarEnd;
122      std::string VarName(AsmString.begin()+DollarPos+1,
123                          AsmString.begin()+VarEnd);
124
125      // Modifier - Support ${foo:modifier} syntax, where "modifier" is passed
126      // into printOperand.  Also support ${:feature}, which is passed into
127      // PrintSpecial.
128      std::string Modifier;
129
130      // In order to avoid starting the next string at the terminating curly
131      // brace, advance the end position past it if we found an opening curly
132      // brace.
133      if (hasCurlyBraces) {
134        if (VarEnd >= AsmString.size())
135          PrintFatalError("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("Reached end of string before terminating curly brace in '"
143              + CGI.TheDef->getName() + "'");
144
145          unsigned ModifierStart = VarEnd;
146          while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
147            ++VarEnd;
148          Modifier = std::string(AsmString.begin()+ModifierStart,
149                                 AsmString.begin()+VarEnd);
150          if (Modifier.empty())
151            PrintFatalError("Bad operand modifier name in '"+ CGI.TheDef->getName() + "'");
152        }
153
154        if (AsmString[VarEnd] != '}')
155          PrintFatalError("Variable name beginning with '{' did not end with '}' in '"
156            + CGI.TheDef->getName() + "'");
157        ++VarEnd;
158      }
159      if (VarName.empty() && Modifier.empty())
160        PrintFatalError("Stray '$' in '" + CGI.TheDef->getName() +
161          "' asm string, maybe you want $$?");
162
163      if (VarName.empty()) {
164        // Just a modifier, pass this into PrintSpecial.
165        Operands.push_back(AsmWriterOperand("PrintSpecial",
166                                            ~0U,
167                                            ~0U,
168                                            Modifier));
169      } else {
170        // Otherwise, normal operand.
171        unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
172        CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
173
174        unsigned MIOp = OpInfo.MIOperandNo;
175        Operands.push_back(AsmWriterOperand(OpInfo.PrinterMethodName,
176                                            OpNo, MIOp, Modifier));
177      }
178      LastEmitted = VarEnd;
179    }
180  }
181
182  Operands.push_back(AsmWriterOperand("return;",
183    AsmWriterOperand::isLiteralStatementOperand));
184}
185
186/// MatchesAllButOneOp - If this instruction is exactly identical to the
187/// specified instruction except for one differing operand, return the differing
188/// operand number.  If more than one operand mismatches, return ~1, otherwise
189/// if the instructions are identical return ~0.
190unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other)const{
191  if (Operands.size() != Other.Operands.size()) return ~1;
192
193  unsigned MismatchOperand = ~0U;
194  for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
195    if (Operands[i] != Other.Operands[i]) {
196      if (MismatchOperand != ~0U)  // Already have one mismatch?
197        return ~1U;
198      MismatchOperand = i;
199    }
200  }
201  return MismatchOperand;
202}
203