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 "CodeGenInstruction.h"
15#include "llvm/ADT/StringExtras.h"
16#include "llvm/TableGen/Error.h"
17#include "llvm/TableGen/Record.h"
18
19using namespace llvm;
20
21static bool isIdentChar(char C) { return isAlnum(C) || C == '_'; }
22
23std::string AsmWriterOperand::getCode(bool PassSubtarget) const {
24 if (OperandType == isLiteralTextOperand) {
25 if (Str.size() == 1)
26 return "O << '" + Str + "';";
27 return "O << \"" + Str + "\";";
28 }
29
30 if (OperandType == isLiteralStatementOperand)
31 return Str;
32
33 std::string Result = Str + "(MI";
34 if (PCRel)
35 Result += ", Address";
36 if (MIOpNo != ~0U)
37 Result += ", " + utostr(X: MIOpNo);
38 if (PassSubtarget)
39 Result += ", STI";
40 Result += ", O";
41 if (!MiModifier.empty())
42 Result += ", \"" + MiModifier + '"';
43 return Result + ");";
44}
45
46/// ParseAsmString - Parse the specified Instruction's AsmString into this
47/// AsmWriterInst.
48///
49AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI, unsigned CGIIndex,
50 unsigned Variant)
51 : CGI(&CGI), CGIIndex(CGIIndex) {
52
53 // NOTE: Any extensions to this code need to be mirrored in the
54 // AsmPrinter::printInlineAsm code that executes as compile time (assuming
55 // that inline asm strings should also get the new feature)!
56 std::string AsmString = CGI.FlattenAsmStringVariants(AsmString: CGI.AsmString, Variant);
57 std::string::size_type LastEmitted = 0;
58 while (LastEmitted != AsmString.size()) {
59 std::string::size_type DollarPos =
60 AsmString.find_first_of(s: "$\\", pos: LastEmitted);
61 if (DollarPos == std::string::npos)
62 DollarPos = AsmString.size();
63
64 // Emit a constant string fragment.
65 if (DollarPos != LastEmitted) {
66 for (; LastEmitted != DollarPos; ++LastEmitted)
67 switch (AsmString[LastEmitted]) {
68 case '\n':
69 AddLiteralString(Str: "\\n");
70 break;
71 case '\t':
72 AddLiteralString(Str: "\\t");
73 break;
74 case '"':
75 AddLiteralString(Str: "\\\"");
76 break;
77 case '\\':
78 AddLiteralString(Str: "\\\\");
79 break;
80 default:
81 AddLiteralString(Str: std::string(1, AsmString[LastEmitted]));
82 break;
83 }
84 } else if (AsmString[DollarPos] == '\\') {
85 if (DollarPos + 1 != AsmString.size()) {
86 if (AsmString[DollarPos + 1] == 'n') {
87 AddLiteralString(Str: "\\n");
88 } else if (AsmString[DollarPos + 1] == 't') {
89 AddLiteralString(Str: "\\t");
90 } else if (std::string("${|}\\").find(c: AsmString[DollarPos + 1]) !=
91 std::string::npos) {
92 AddLiteralString(Str: std::string(1, AsmString[DollarPos + 1]));
93 } else {
94 PrintFatalError(
95 ErrorLoc: CGI.TheDef->getLoc(),
96 Msg: "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] == '$') {
104 AddLiteralString(Str: "$"); // "$$" -> $
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(C: AsmString[VarEnd]))
121 ++VarEnd;
122 StringRef VarName(AsmString.data() + DollarPos + 1,
123 VarEnd - DollarPos - 1);
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(
136 ErrorLoc: CGI.TheDef->getLoc(),
137 Msg: "Reached end of string before terminating curly brace in '" +
138 CGI.TheDef->getName() + "'");
139
140 // Look for a modifier string.
141 if (AsmString[VarEnd] == ':') {
142 ++VarEnd;
143 if (VarEnd >= AsmString.size())
144 PrintFatalError(
145 ErrorLoc: CGI.TheDef->getLoc(),
146 Msg: "Reached end of string before terminating curly brace in '" +
147 CGI.TheDef->getName() + "'");
148
149 std::string::size_type ModifierStart = VarEnd;
150 while (VarEnd < AsmString.size() && isIdentChar(C: AsmString[VarEnd]))
151 ++VarEnd;
152 Modifier = AsmString.substr(pos: ModifierStart, n: VarEnd - ModifierStart);
153 if (Modifier.empty())
154 PrintFatalError(ErrorLoc: CGI.TheDef->getLoc(),
155 Msg: "Bad operand modifier name in '" +
156 CGI.TheDef->getName() + "'");
157 }
158
159 if (AsmString[VarEnd] != '}')
160 PrintFatalError(
161 ErrorLoc: CGI.TheDef->getLoc(),
162 Msg: "Variable name beginning with '{' did not end with '}' in '" +
163 CGI.TheDef->getName() + "'");
164 ++VarEnd;
165 }
166 if (VarName.empty() && Modifier.empty())
167 PrintFatalError(ErrorLoc: CGI.TheDef->getLoc(),
168 Msg: "Stray '$' in '" + CGI.TheDef->getName() +
169 "' asm string, maybe you want $$?");
170
171 if (VarName.empty()) {
172 // Just a modifier, pass this into PrintSpecial.
173 Operands.emplace_back(args: "PrintSpecial", args: ~0U, args&: Modifier);
174 } else {
175 // Otherwise, normal operand.
176 unsigned OpNo = CGI.Operands.getOperandNamed(Name: VarName);
177 CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
178
179 unsigned MIOp = OpInfo.MIOperandNo;
180 Operands.emplace_back(args: OpInfo.PrinterMethodName.str(), args&: MIOp, args&: Modifier,
181 args: AsmWriterOperand::isMachineInstrOperand,
182 args: OpInfo.OperandType == "MCOI::OPERAND_PCREL");
183 }
184 LastEmitted = VarEnd;
185 }
186 }
187
188 Operands.emplace_back(args: "return;", args: 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.
195unsigned AsmWriterInst::MatchesAllButOneOp(const AsmWriterInst &Other) const {
196 if (Operands.size() != Other.Operands.size())
197 return ~1;
198
199 unsigned MismatchOperand = ~0U;
200 for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
201 if (Operands[i] != Other.Operands[i]) {
202 if (MismatchOperand != ~0U) // Already have one mismatch?
203 return ~1U;
204 MismatchOperand = i;
205 }
206 }
207 return MismatchOperand;
208}
209