1 //===- MILexer.cpp - Machine instructions lexer implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the lexing of machine instructions.
12 //===----------------------------------------------------------------------===//
15 #include "llvm/ADT/StringSwitch.h"
16 #include "llvm/ADT/Twine.h"
23 /// This class provides a way to iterate and get characters from the source
30 Cursor(NoneType) : Ptr(nullptr), End(nullptr) {}
32 explicit Cursor(StringRef Str) {
34 End = Ptr + Str.size();
37 bool isEOF() const { return Ptr == End; }
39 char peek(int I = 0) const { return End - Ptr <= I ? 0 : Ptr[I]; }
41 void advance(unsigned I = 1) { Ptr += I; }
43 StringRef remaining() const { return StringRef(Ptr, End - Ptr); }
45 StringRef upto(Cursor C) const {
46 assert(C.Ptr >= Ptr && C.Ptr <= End);
47 return StringRef(Ptr, C.Ptr - Ptr);
50 StringRef::iterator location() const { return Ptr; }
52 operator bool() const { return Ptr != nullptr; }
55 } // end anonymous namespace
57 /// Skip the leading whitespace characters and return the updated cursor.
58 static Cursor skipWhitespace(Cursor C) {
59 while (isspace(C.peek()))
64 static bool isIdentifierChar(char C) {
65 return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.';
68 static MIToken::TokenKind getIdentifierKind(StringRef Identifier) {
69 return StringSwitch<MIToken::TokenKind>(Identifier)
70 .Case("_", MIToken::underscore)
71 .Case("implicit", MIToken::kw_implicit)
72 .Case("implicit-def", MIToken::kw_implicit_define)
73 .Case("dead", MIToken::kw_dead)
74 .Default(MIToken::Identifier);
77 static Cursor maybeLexIdentifier(Cursor C, MIToken &Token) {
78 if (!isalpha(C.peek()) && C.peek() != '_')
81 while (isIdentifierChar(C.peek()))
83 auto Identifier = Range.upto(C);
84 Token = MIToken(getIdentifierKind(Identifier), Identifier);
88 static Cursor maybeLexMachineBasicBlock(
89 Cursor C, MIToken &Token,
90 function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
91 if (!C.remaining().startswith("%bb."))
94 C.advance(4); // Skip '%bb.'
95 if (!isdigit(C.peek())) {
96 Token = MIToken(MIToken::Error, C.remaining());
97 ErrorCallback(C.location(), "expected a number after '%bb.'");
100 auto NumberRange = C;
101 while (isdigit(C.peek()))
103 StringRef Number = NumberRange.upto(C);
104 unsigned StringOffset = 4 + Number.size(); // Drop '%bb.<id>'
105 if (C.peek() == '.') {
106 C.advance(); // Skip '.'
108 while (isIdentifierChar(C.peek()))
111 Token = MIToken(MIToken::MachineBasicBlock, Range.upto(C), APSInt(Number),
116 static Cursor maybeLexRegister(Cursor C, MIToken &Token) {
120 C.advance(); // Skip '%'
121 while (isIdentifierChar(C.peek()))
123 Token = MIToken(MIToken::NamedRegister, Range.upto(C),
124 /*StringOffset=*/1); // Drop the '%'
128 static Cursor maybeLexGlobalValue(Cursor C, MIToken &Token) {
132 C.advance(); // Skip the '@'
133 // TODO: add support for quoted names.
134 if (!isdigit(C.peek())) {
135 while (isIdentifierChar(C.peek()))
137 Token = MIToken(MIToken::NamedGlobalValue, Range.upto(C),
138 /*StringOffset=*/1); // Drop the '@'
141 auto NumberRange = C;
142 while (isdigit(C.peek()))
145 MIToken(MIToken::GlobalValue, Range.upto(C), APSInt(NumberRange.upto(C)));
149 static Cursor maybeLexIntegerLiteral(Cursor C, MIToken &Token) {
150 if (!isdigit(C.peek()) && (C.peek() != '-' || !isdigit(C.peek(1))))
154 while (isdigit(C.peek()))
156 StringRef StrVal = Range.upto(C);
157 Token = MIToken(MIToken::IntegerLiteral, StrVal, APSInt(StrVal));
161 static MIToken::TokenKind symbolToken(char C) {
164 return MIToken::comma;
166 return MIToken::equal;
168 return MIToken::Error;
172 static Cursor maybeLexSymbol(Cursor C, MIToken &Token) {
173 auto Kind = symbolToken(C.peek());
174 if (Kind == MIToken::Error)
178 Token = MIToken(Kind, Range.upto(C));
182 StringRef llvm::lexMIToken(
183 StringRef Source, MIToken &Token,
184 function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
185 auto C = skipWhitespace(Cursor(Source));
187 Token = MIToken(MIToken::Eof, C.remaining());
188 return C.remaining();
191 if (Cursor R = maybeLexIdentifier(C, Token))
192 return R.remaining();
193 if (Cursor R = maybeLexMachineBasicBlock(C, Token, ErrorCallback))
194 return R.remaining();
195 if (Cursor R = maybeLexRegister(C, Token))
196 return R.remaining();
197 if (Cursor R = maybeLexGlobalValue(C, Token))
198 return R.remaining();
199 if (Cursor R = maybeLexIntegerLiteral(C, Token))
200 return R.remaining();
201 if (Cursor R = maybeLexSymbol(C, Token))
202 return R.remaining();
204 Token = MIToken(MIToken::Error, C.remaining());
205 ErrorCallback(C.location(),
206 Twine("unexpected character '") + Twine(C.peek()) + "'");
207 return C.remaining();