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fbfb76a515
<rdar://problem/10718220> Need a better name than 'plus' for "static" functions Swift SVN r1340
460 lines
13 KiB
C++
460 lines
13 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 "swift/Parse/Lexer.h"
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/Diagnostics.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(StringRef Buffer, llvm::SourceMgr &SourceMgr,
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DiagnosticEngine *Diags, const char *CurrentPosition)
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: SourceMgr(SourceMgr), Diags(Diags) {
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BufferStart = Buffer.begin();
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BufferEnd = Buffer.end();
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CurPtr = CurrentPosition;
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assert(CurPtr >= BufferStart && CurPtr <= BufferEnd &&
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"Current position is out-of-range");
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// Prime the lexer.
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lexImpl();
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}
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InFlightDiagnostic Lexer::diagnose(const char *Loc, Diag<> ID) {
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if (Diags)
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Diags->diagnose(getSourceLoc(Loc), ID);
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return InFlightDiagnostic();
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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 != BufferEnd) {
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diagnose(CurPtr-1, diag::lex_nul_character);
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break;
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}
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// Otherwise, we have a // comment at end of file.
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--CurPtr;
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return;
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}
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}
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}
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/// skipSlashStarComment - /**/ comments are skipped (treated as whitespace).
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/// Note that (unlike in C) block comments can be nested.
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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 != BufferEnd) {
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diagnose(CurPtr-1, diag::lex_nul_character);
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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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diagnose(CurPtr-(CurPtr[-1] == '\n'),
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diag::lex_unterminated_block_comment);
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diagnose(StartPtr, diag::lex_comment_start);
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return;
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}
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}
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}
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static bool isValidStartOfIdentifier(char c) {
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return isalpha(c) || c == '_';
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}
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static bool isValidContinuationOfIdentifier(char c) {
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return isalnum(c) || c == '_' || c == '$';
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}
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/// isIdentifier - Checks whether a string matches the identifier regex.
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bool Lexer::isIdentifier(llvm::StringRef string) {
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if (string.empty()) return false;
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if (!isValidStartOfIdentifier(string[0])) return false;
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for (unsigned i = 1, e = string.size(); i != e; ++i)
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if (!isValidContinuationOfIdentifier(string[i]))
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return false;
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return true;
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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(isValidStartOfIdentifier(*TokStart) && "Unexpected start");
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// Lex [a-zA-Z_$0-9]*
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while (isValidContinuationOfIdentifier(*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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// decl and type keywords
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.Case("extension", tok::kw_extension)
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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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.Case("static", tok::kw_static)
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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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// Return true if the string starts with "[eE][+-][0-9]"
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static bool isValidExponent(const char *P) {
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if (*P != 'e' && *P != 'E')
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return false;
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++P;
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if (*P != '+' && *P != '-')
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return false;
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++P;
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return isdigit(*P);
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}
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/// lexNumber:
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/// integer_literal ::= [0-9]+
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/// integer_literal ::= 0x[0-9a-fA-F]+
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/// integer_literal ::= 0o[0-7]+
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/// integer_literal ::= 0b[01]+
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/// floating_literal ::= [0-9]+(\.[0-9]+)?
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/// floating_literal ::= [0-9]+(\.[0-9]*)?[eE][+-][0-9]+
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/// floating_literal ::= \.[0-9]+([eE][+-][0-9]+)?
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void Lexer::lexNumber() {
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const char *TokStart = CurPtr-1;
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assert((isdigit(*TokStart) || *TokStart == '.') && "Unexpected start");
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if (*TokStart == '0' && *CurPtr == 'x') {
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// 0x[0-9a-fA-F]+
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++CurPtr;
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while (isdigit(*CurPtr) ||
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(*CurPtr >= 'a' && *CurPtr <= 'f') ||
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(*CurPtr >= 'A' && *CurPtr <= 'F'))
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++CurPtr;
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if (CurPtr - TokStart == 2) {
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diagnose(CurPtr, diag::lex_expected_digit_in_int_literal);
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return formToken(tok::unknown, TokStart);
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}
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return formToken(tok::integer_literal, TokStart);
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} else if (*TokStart == '0' && *CurPtr == 'o') {
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// 0o[0-7]+
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++CurPtr;
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while (*CurPtr >= '0' && *CurPtr <= '7')
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++CurPtr;
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if (CurPtr - TokStart == 2) {
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diagnose(CurPtr, diag::lex_expected_digit_in_int_literal);
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return formToken(tok::unknown, TokStart);
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}
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return formToken(tok::integer_literal, TokStart);
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} else if (*TokStart == '0' && *CurPtr == 'b') {
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// 0b[01]+
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++CurPtr;
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while (*CurPtr == '0' || *CurPtr == '1')
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++CurPtr;
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if (CurPtr - TokStart == 2) {
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diagnose(CurPtr, diag::lex_expected_digit_in_int_literal);
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return formToken(tok::unknown, TokStart);
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}
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return formToken(tok::integer_literal, TokStart);
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}
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// Handle the leading character here as well.
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--CurPtr;
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// Handle a leading [0-9]+, lexing an integer or falling through if we have a
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// floating point value.
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if (isdigit(*CurPtr)) {
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while (isdigit(*CurPtr))
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++CurPtr;
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// Floating literals must have '.', 'e', or 'E' after digits. If it is
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// something else, then this is the end of the token.
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if (*CurPtr != '.' && *CurPtr != 'e' && *CurPtr != 'E')
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return formToken(tok::integer_literal, TokStart);
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// Lex things like 4.x as '4' followed by a tok::period.
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if (*CurPtr == '.' && !isdigit(CurPtr[1]) && !isValidExponent(CurPtr+1))
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return formToken(tok::integer_literal, TokStart);
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}
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// Lex decimal point.
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if (*CurPtr == '.') {
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++CurPtr;
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// Lex any digits after the decimal point.
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while (isdigit(*CurPtr))
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++CurPtr;
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}
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// Lex exponent.
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if (*CurPtr == 'e' || *CurPtr == 'E') {
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++CurPtr; // Eat the 'e'
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if (*CurPtr != '+' && *CurPtr != '-') {
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diagnose(CurPtr, diag::lex_expected_sign_in_fp);
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return formToken(tok::unknown, TokStart);
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}
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++CurPtr; // Eat the sign.
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if (!isdigit(*CurPtr)) {
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diagnose(CurPtr, diag::lex_expected_digit_in_fp_exponent);
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return formToken(tok::unknown, TokStart);
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}
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while (isdigit(*CurPtr))
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++CurPtr;
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}
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return formToken(tok::floating_literal, 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 >= BufferStart &&
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CurPtr <= BufferEnd && "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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diagnose(CurPtr-1, diag::lex_invalid_character);
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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 != BufferEnd) {
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diagnose(CurPtr-1, diag::lex_nul_character);
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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 == BufferStart) {
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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 '.':
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if (isdigit(CurPtr[0])) // .42
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return lexNumber();
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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 ':': return formToken(tok::colon, 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 operator 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 lexNumber();
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}
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}
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SourceLoc Lexer::getLocForEndOfToken(llvm::SourceMgr &SM, SourceLoc Loc) {
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// Don't try to do anything with an invalid location.
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if (!Loc.isValid())
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return Loc;
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// Figure out which buffer contains this location.
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int BufferID = SM.FindBufferContainingLoc(Loc.Value);
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if (BufferID < 0)
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return SourceLoc();
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const llvm::MemoryBuffer *Buffer = SM.getMemoryBuffer(BufferID);
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if (!Buffer)
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return SourceLoc();
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Lexer L(Buffer->getBuffer(), SM, 0, Loc.Value.getPointer());
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unsigned Length = L.peekNextToken().getLength();
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return Loc.getAdvancedLoc(Length);
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}
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