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339 lines
9.9 KiB
C++
339 lines
9.9 KiB
C++
//===--- Lexer.cpp - Swift Language Lexer ---------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the Lexer and Token interfaces.
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//
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//===----------------------------------------------------------------------===//
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#include "Lexer.h"
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/Identifier.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/SourceMgr.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/ADT/Twine.h"
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using namespace swift;
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//===----------------------------------------------------------------------===//
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// Setup and Helper Methods
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//===----------------------------------------------------------------------===//
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Lexer::Lexer(unsigned BufferID, ASTContext &context)
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: SourceMgr(context.SourceMgr), Context(context) {
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Buffer = SourceMgr.getMemoryBuffer(BufferID);
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CurPtr = Buffer->getBufferStart();
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// Prime the lexer.
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lexImpl();
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}
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void Lexer::note(const char *Loc, const Twine &Message) {
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SourceMgr.PrintMessage(SMLoc::getFromPointer(Loc), Message, "note");
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}
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void Lexer::warning(const char *Loc, const Twine &Message) {
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SourceMgr.PrintMessage(SMLoc::getFromPointer(Loc), Message, "warning");
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}
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void Lexer::error(const char *Loc, const Twine &Message) {
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Context.setHadError();
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SourceMgr.PrintMessage(SMLoc::getFromPointer(Loc), Twine(Message),
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"error");
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}
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void Lexer::formToken(tok Kind, const char *TokStart) {
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NextToken.setToken(Kind, StringRef(TokStart, CurPtr-TokStart));
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}
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//===----------------------------------------------------------------------===//
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// Lexer Subroutines
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//===----------------------------------------------------------------------===//
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/// skipSlashSlashComment - Skip to the end of the line of a // comment.
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void Lexer::skipSlashSlashComment() {
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assert(CurPtr[-1] == '/' && CurPtr[0] == '/' && "Not a // comment");
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while (1) {
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switch (*CurPtr++) {
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case '\n':
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case '\r':
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return; // If we found the end of the line, return.
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default:
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break; // Otherwise, eat other characters.
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case 0:
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// If this is a random nul character in the middle of a buffer, skip it as
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// whitespace.
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if (CurPtr-1 != Buffer->getBufferEnd()) {
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warning(CurPtr-1, "nul character embedded in middle of file");
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break;
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}
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// Otherwise, we have a // comment at end of file, warn and return.
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--CurPtr;
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warning(CurPtr-1, "no newline at end of // comment");
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return;
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}
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}
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}
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void Lexer::skipSlashStarComment() {
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const char *StartPtr = CurPtr-1;
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assert(CurPtr[-1] == '/' && CurPtr[0] == '*' && "Not a /* comment");
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// Make sure to advance over the * so that we don't incorrectly handle /*/ as
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// the beginning and end of the comment.
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++CurPtr;
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// /**/ comments can be nested, keep track of how deep we've gone.
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unsigned Depth = 1;
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while (1) {
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switch (*CurPtr++) {
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case '*':
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// Check for a '*/'
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if (*CurPtr == '/') {
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++CurPtr;
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if (--Depth == 0)
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return;
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}
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break;
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case '/':
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// Check for a '/*'
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if (*CurPtr == '*') {
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++CurPtr;
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++Depth;
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}
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break;
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default:
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break; // Otherwise, eat other characters.
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case 0:
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// If this is a random nul character in the middle of a buffer, skip it as
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// whitespace.
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if (CurPtr-1 != Buffer->getBufferEnd()) {
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warning(CurPtr-1, "nul character embedded in middle of file");
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break;
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}
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// Otherwise, we have an unterminated /* comment.
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--CurPtr;
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error(CurPtr-(CurPtr[-1] == '\n'), "unterminated '/*' comment");
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note(StartPtr, "comment started here");
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return;
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}
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}
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}
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/// lexIdentifier - Match [a-zA-Z_][a-zA-Z_$0-9]*
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void Lexer::lexIdentifier() {
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const char *TokStart = CurPtr-1;
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assert((isalpha(*TokStart) || *TokStart == '_') && "Unexpected start");
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// Lex [a-zA-Z_$0-9]*
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while (isalnum(*CurPtr) || *CurPtr == '_' || *CurPtr == '$')
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++CurPtr;
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tok Kind =
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llvm::StringSwitch<tok>(StringRef(TokStart, CurPtr-TokStart))
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.Case("__builtin_double_type",tok::kw___builtin_double_type)
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.Case("__builtin_float_type", tok::kw___builtin_float_type)
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.Case("__builtin_int1_type", tok::kw___builtin_int1_type)
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.Case("__builtin_int8_type", tok::kw___builtin_int8_type)
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.Case("__builtin_int16_type", tok::kw___builtin_int16_type)
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.Case("__builtin_int32_type", tok::kw___builtin_int32_type)
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.Case("__builtin_int64_type", tok::kw___builtin_int64_type)
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// decl and type keywords
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.Case("import", tok::kw_import)
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.Case("func", tok::kw_func)
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.Case("oneof", tok::kw_oneof)
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.Case("protocol", tok::kw_protocol)
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.Case("struct", tok::kw_struct)
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.Case("typealias", tok::kw_typealias)
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.Case("var", tok::kw_var)
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// Statements
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.Case("if", tok::kw_if)
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.Case("else", tok::kw_else)
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.Case("while", tok::kw_while)
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.Case("return", tok::kw_return)
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.Default(tok::identifier);
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return formToken(Kind, TokStart);
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}
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/// lexOperatorIdentifier - Match identifiers formed out of punctuation.
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void Lexer::lexOperatorIdentifier() {
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const char *TokStart = CurPtr-1;
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while (Identifier::isOperatorChar(*CurPtr))
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++CurPtr;
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// Match various reserved words.
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if (CurPtr-TokStart == 1) {
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switch (TokStart[0]) {
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case '=': return formToken(tok::equal, TokStart);
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}
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} else if (CurPtr-TokStart == 2) {
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switch ((TokStart[0] << 8) | TokStart[1]) {
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case ('-' << 8) | '>': // ->
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return formToken(tok::arrow, TokStart);
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}
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}
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return formToken(tok::oper, TokStart);
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}
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/// lexDollarIdent - Match $[0-9a-zA-Z_$]*
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void Lexer::lexDollarIdent() {
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const char *TokStart = CurPtr-1;
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assert(*TokStart == '$');
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// Lex [a-zA-Z_$0-9]*
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while (isalnum(*CurPtr) || *CurPtr == '_' || *CurPtr == '$')
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++CurPtr;
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return formToken(tok::dollarident, TokStart);
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}
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/// lexDigit - Match [0-9]+
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void Lexer::lexDigit() {
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const char *TokStart = CurPtr-1;
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assert(isdigit(*TokStart) && "Unexpected start");
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// Lex [0-9]*
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while (isdigit(*CurPtr))
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++CurPtr;
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return formToken(tok::numeric_constant, TokStart);
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}
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//===----------------------------------------------------------------------===//
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// Main Lexer Loop
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//===----------------------------------------------------------------------===//
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void Lexer::lexImpl() {
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assert(CurPtr >= Buffer->getBufferStart() &&
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CurPtr <= Buffer->getBufferEnd() && "Cur Char Pointer out of range!");
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Restart:
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// Remember the start of the token so we can form the text range.
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const char *TokStart = CurPtr;
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switch (*CurPtr++) {
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default:
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error(CurPtr-1, "invalid character in source file");
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return formToken(tok::unknown, TokStart);
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case ' ':
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case '\t':
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case '\n':
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case '\r':
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goto Restart; // Skip whitespace.
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case 0:
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// If this is a random nul character in the middle of a buffer, skip it as
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// whitespace.
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if (CurPtr-1 != Buffer->getBufferEnd()) {
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warning(CurPtr-1, "nul character embedded in middle of file");
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goto Restart;
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}
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// Otherwise, this is the end of the buffer. Return EOF.
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return formToken(tok::eof, TokStart);
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case '(': {
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// This is either l_paren or l_paren_space depending on whether there is
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// whitespace before it.
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bool PrecededBySpace;
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// For these purposes, the start of the file is considered to be
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// preceeded by infinite whitespace.
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if (CurPtr - 1 == Buffer->getBufferStart()) {
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PrecededBySpace = true;
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// Otherwise, our list of whitespace characters is pretty short.
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} else {
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char LastChar = *(CurPtr - 2);
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PrecededBySpace = (isspace(LastChar) || LastChar == '\0');
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}
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if (PrecededBySpace)
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return formToken(tok::l_paren_space, TokStart);
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return formToken(tok::l_paren, TokStart);
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}
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case ')': return formToken(tok::r_paren, TokStart);
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case '{': return formToken(tok::l_brace, TokStart);
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case '}': return formToken(tok::r_brace, TokStart);
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case '[': return formToken(tok::l_square, TokStart);
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case ']': return formToken(tok::r_square, TokStart);
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case '.': return formToken(tok::period, TokStart);
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case ',': return formToken(tok::comma, TokStart);
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case ';': return formToken(tok::semi, TokStart);
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case ':':
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if (CurPtr[0] != ':')
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return formToken(tok::colon, TokStart);
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++CurPtr;
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return formToken(tok::coloncolon, TokStart);
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// Punctuator identifier characters.
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case '/':
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if (CurPtr[0] == '/') { // "//"
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skipSlashSlashComment();
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goto Restart;
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}
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if (CurPtr[0] == '*') { // "/*"
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skipSlashStarComment();
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goto Restart;
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}
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// '/' starts an identifier.
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return lexOperatorIdentifier();
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case '=':
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case '-':
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case '+':
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case '*':
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case '%':
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case '<':
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case '>':
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case '!':
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case '&':
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case '|':
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case '^':
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return lexOperatorIdentifier();
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case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
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case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
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case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
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case 'V': case 'W': case 'X': case 'Y': case 'Z':
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case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
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case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
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case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
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case 'v': case 'w': case 'x': case 'y': case 'z':
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case '_':
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return lexIdentifier();
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case '$':
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return lexDollarIdent();
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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return lexDigit();
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}
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}
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