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
20 using namespace llvm;
21
isIdentChar(char C)22 static bool isIdentChar(char C) {
23 return (C >= 'a' && C <= 'z') ||
24 (C >= 'A' && C <= 'Z') ||
25 (C >= '0' && C <= '9') ||
26 C == '_';
27 }
28
getCode() const29 std::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 ///
AsmWriterInst(const CodeGenInstruction & CGI,unsigned Variant,int FirstOperandColumn,int OperandSpacing)51 AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI,
52 unsigned Variant,
53 int FirstOperandColumn,
54 int OperandSpacing) {
55 this->CGI = &CGI;
56
57 // This is the number of tabs we've seen if we're doing columnar layout.
58 unsigned CurColumn = 0;
59
60
61 // NOTE: Any extensions to this code need to be mirrored in the
62 // AsmPrinter::printInlineAsm code that executes as compile time (assuming
63 // that inline asm strings should also get the new feature)!
64 std::string AsmString = CGI.FlattenAsmStringVariants(CGI.AsmString, Variant);
65 std::string::size_type LastEmitted = 0;
66 while (LastEmitted != AsmString.size()) {
67 std::string::size_type DollarPos =
68 AsmString.find_first_of("$\\", LastEmitted);
69 if (DollarPos == std::string::npos) DollarPos = AsmString.size();
70
71 // Emit a constant string fragment.
72 if (DollarPos != LastEmitted) {
73 for (; LastEmitted != DollarPos; ++LastEmitted)
74 switch (AsmString[LastEmitted]) {
75 case '\n':
76 AddLiteralString("\\n");
77 break;
78 case '\t':
79 // If the asm writer is not using a columnar layout, \t is not
80 // magic.
81 if (FirstOperandColumn == -1 || OperandSpacing == -1) {
82 AddLiteralString("\\t");
83 } else {
84 // We recognize a tab as an operand delimeter.
85 unsigned DestColumn = FirstOperandColumn +
86 CurColumn++ * OperandSpacing;
87 Operands.push_back(
88 AsmWriterOperand(
89 "O.PadToColumn(" +
90 utostr(DestColumn) + ");\n",
91 AsmWriterOperand::isLiteralStatementOperand));
92 }
93 break;
94 case '"':
95 AddLiteralString("\\\"");
96 break;
97 case '\\':
98 AddLiteralString("\\\\");
99 break;
100 default:
101 AddLiteralString(std::string(1, AsmString[LastEmitted]));
102 break;
103 }
104 } else if (AsmString[DollarPos] == '\\') {
105 if (DollarPos+1 != AsmString.size()) {
106 if (AsmString[DollarPos+1] == 'n') {
107 AddLiteralString("\\n");
108 } else if (AsmString[DollarPos+1] == 't') {
109 // If the asm writer is not using a columnar layout, \t is not
110 // magic.
111 if (FirstOperandColumn == -1 || OperandSpacing == -1) {
112 AddLiteralString("\\t");
113 break;
114 }
115
116 // We recognize a tab as an operand delimeter.
117 unsigned DestColumn = FirstOperandColumn +
118 CurColumn++ * OperandSpacing;
119 Operands.push_back(
120 AsmWriterOperand("O.PadToColumn(" + utostr(DestColumn) + ");\n",
121 AsmWriterOperand::isLiteralStatementOperand));
122 break;
123 } else if (std::string("${|}\\").find(AsmString[DollarPos+1])
124 != std::string::npos) {
125 AddLiteralString(std::string(1, AsmString[DollarPos+1]));
126 } else {
127 PrintFatalError("Non-supported escaped character found in instruction '" +
128 CGI.TheDef->getName() + "'!");
129 }
130 LastEmitted = DollarPos+2;
131 continue;
132 }
133 } else if (DollarPos+1 != AsmString.size() &&
134 AsmString[DollarPos+1] == '$') {
135 AddLiteralString("$"); // "$$" -> $
136 LastEmitted = DollarPos+2;
137 } else {
138 // Get the name of the variable.
139 std::string::size_type VarEnd = DollarPos+1;
140
141 // handle ${foo}bar as $foo by detecting whether the character following
142 // the dollar sign is a curly brace. If so, advance VarEnd and DollarPos
143 // so the variable name does not contain the leading curly brace.
144 bool hasCurlyBraces = false;
145 if (VarEnd < AsmString.size() && '{' == AsmString[VarEnd]) {
146 hasCurlyBraces = true;
147 ++DollarPos;
148 ++VarEnd;
149 }
150
151 while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
152 ++VarEnd;
153 std::string VarName(AsmString.begin()+DollarPos+1,
154 AsmString.begin()+VarEnd);
155
156 // Modifier - Support ${foo:modifier} syntax, where "modifier" is passed
157 // into printOperand. Also support ${:feature}, which is passed into
158 // PrintSpecial.
159 std::string Modifier;
160
161 // In order to avoid starting the next string at the terminating curly
162 // brace, advance the end position past it if we found an opening curly
163 // brace.
164 if (hasCurlyBraces) {
165 if (VarEnd >= AsmString.size())
166 PrintFatalError("Reached end of string before terminating curly brace in '"
167 + CGI.TheDef->getName() + "'");
168
169 // Look for a modifier string.
170 if (AsmString[VarEnd] == ':') {
171 ++VarEnd;
172 if (VarEnd >= AsmString.size())
173 PrintFatalError("Reached end of string before terminating curly brace in '"
174 + CGI.TheDef->getName() + "'");
175
176 unsigned ModifierStart = VarEnd;
177 while (VarEnd < AsmString.size() && isIdentChar(AsmString[VarEnd]))
178 ++VarEnd;
179 Modifier = std::string(AsmString.begin()+ModifierStart,
180 AsmString.begin()+VarEnd);
181 if (Modifier.empty())
182 PrintFatalError("Bad operand modifier name in '"+ CGI.TheDef->getName() + "'");
183 }
184
185 if (AsmString[VarEnd] != '}')
186 PrintFatalError("Variable name beginning with '{' did not end with '}' in '"
187 + CGI.TheDef->getName() + "'");
188 ++VarEnd;
189 }
190 if (VarName.empty() && Modifier.empty())
191 PrintFatalError("Stray '$' in '" + CGI.TheDef->getName() +
192 "' asm string, maybe you want $$?");
193
194 if (VarName.empty()) {
195 // Just a modifier, pass this into PrintSpecial.
196 Operands.push_back(AsmWriterOperand("PrintSpecial",
197 ~0U,
198 ~0U,
199 Modifier));
200 } else {
201 // Otherwise, normal operand.
202 unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
203 CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
204
205 unsigned MIOp = OpInfo.MIOperandNo;
206 Operands.push_back(AsmWriterOperand(OpInfo.PrinterMethodName,
207 OpNo, MIOp, Modifier));
208 }
209 LastEmitted = VarEnd;
210 }
211 }
212
213 Operands.push_back(AsmWriterOperand("return;",
214 AsmWriterOperand::isLiteralStatementOperand));
215 }
216
217 /// MatchesAllButOneOp - If this instruction is exactly identical to the
218 /// specified instruction except for one differing operand, return the differing
219 /// operand number. If more than one operand mismatches, return ~1, otherwise
220 /// if the instructions are identical return ~0.
MatchesAllButOneOp(const AsmWriterInst & Other) const221 unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other)const{
222 if (Operands.size() != Other.Operands.size()) return ~1;
223
224 unsigned MismatchOperand = ~0U;
225 for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
226 if (Operands[i] != Other.Operands[i]) {
227 if (MismatchOperand != ~0U) // Already have one mismatch?
228 return ~1U;
229 MismatchOperand = i;
230 }
231 }
232 return MismatchOperand;
233 }
234