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/Twine.h"
22 /// This class provides a way to iterate and get characters from the source
29 explicit Cursor(StringRef Str) {
31 End = Ptr + Str.size();
34 bool isEOF() const { return Ptr == End; }
36 char peek(int I = 0) const { return End - Ptr <= I ? 0 : Ptr[I]; }
38 void advance(unsigned I = 1) { Ptr += I; }
40 StringRef remaining() const { return StringRef(Ptr, End - Ptr); }
42 StringRef upto(Cursor C) const {
43 assert(C.Ptr >= Ptr && C.Ptr <= End);
44 return StringRef(Ptr, C.Ptr - Ptr);
47 StringRef::iterator location() const { return Ptr; }
50 } // end anonymous namespace
52 /// Skip the leading whitespace characters and return the updated cursor.
53 static Cursor skipWhitespace(Cursor C) {
54 while (isspace(C.peek()))
59 static bool isIdentifierChar(char C) {
60 return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.';
63 static Cursor lexIdentifier(Cursor C, MIToken &Token) {
65 while (isIdentifierChar(C.peek()))
67 auto Identifier = Range.upto(C);
68 Token = MIToken(Identifier == "_" ? MIToken::underscore : MIToken::Identifier,
73 static Cursor lexMachineBasicBlock(
74 Cursor C, MIToken &Token,
75 function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
77 C.advance(4); // Skip '%bb.'
78 if (!isdigit(C.peek())) {
79 Token = MIToken(MIToken::Error, C.remaining());
80 ErrorCallback(C.location(), "expected a number after '%bb.'");
84 while (isdigit(C.peek()))
86 StringRef Number = NumberRange.upto(C);
87 unsigned StringOffset = 4 + Number.size(); // Drop '%bb.<id>'
88 if (C.peek() == '.') {
89 C.advance(); // Skip '.'
91 while (isIdentifierChar(C.peek()))
94 Token = MIToken(MIToken::MachineBasicBlock, Range.upto(C), APSInt(Number),
99 static Cursor lexPercent(Cursor C, MIToken &Token) {
101 C.advance(); // Skip '%'
102 while (isIdentifierChar(C.peek()))
104 Token = MIToken(MIToken::NamedRegister, Range.upto(C),
105 /*StringOffset=*/1); // Drop the '%'
109 static Cursor lexIntegerLiteral(Cursor C, MIToken &Token) {
112 while (isdigit(C.peek()))
114 StringRef StrVal = Range.upto(C);
115 Token = MIToken(MIToken::IntegerLiteral, StrVal, APSInt(StrVal));
119 static MIToken::TokenKind symbolToken(char C) {
122 return MIToken::comma;
124 return MIToken::equal;
126 return MIToken::Error;
130 static Cursor lexSymbol(Cursor C, MIToken::TokenKind Kind, MIToken &Token) {
133 Token = MIToken(Kind, Range.upto(C));
137 StringRef llvm::lexMIToken(
138 StringRef Source, MIToken &Token,
139 function_ref<void(StringRef::iterator Loc, const Twine &)> ErrorCallback) {
140 auto C = skipWhitespace(Cursor(Source));
142 Token = MIToken(MIToken::Eof, C.remaining());
143 return C.remaining();
146 auto Char = C.peek();
147 if (isalpha(Char) || Char == '_')
148 return lexIdentifier(C, Token).remaining();
150 if (C.remaining().startswith("%bb."))
151 return lexMachineBasicBlock(C, Token, ErrorCallback).remaining();
152 return lexPercent(C, Token).remaining();
154 if (isdigit(Char) || (Char == '-' && isdigit(C.peek(1))))
155 return lexIntegerLiteral(C, Token).remaining();
156 MIToken::TokenKind Kind = symbolToken(Char);
157 if (Kind != MIToken::Error)
158 return lexSymbol(C, Kind, Token).remaining();
159 Token = MIToken(MIToken::Error, C.remaining());
160 ErrorCallback(C.location(),
161 Twine("unexpected character '") + Twine(Char) + "'");
162 return C.remaining();