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Lexer.cpp
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//===--- Lexer.cpp - Swift Language Lexer ---------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements the Lexer and Token interfaces.
//
//===----------------------------------------------------------------------===//
#include "swift/Parse/Lexer.h"
#include "swift/AST/DiagnosticsParse.h"
#include "swift/AST/Identifier.h"
#include "swift/Basic/LangOptions.h"
#include "swift/Basic/SourceManager.h"
#include "swift/Bridging/ASTGen.h"
#include "swift/Parse/Confusables.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Twine.h"
#include "llvm/ADT/bit.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
// FIXME: Figure out if this can be migrated to LLVM.
#include "clang/Basic/CharInfo.h"
#include <limits>
using namespace swift;
// clang::isAsciiIdentifierStart and clang::isAsciiIdentifierContinue are
// deliberately not in this list as a reminder that they are using C rules for
// identifiers. (Admittedly these are the same as Swift's right now.)
using clang::isAlphanumeric;
using clang::isDigit;
using clang::isHexDigit;
using clang::isHorizontalWhitespace;
using clang::isPrintable;
using clang::isWhitespace;
//===----------------------------------------------------------------------===//
// UTF8 Validation/Encoding/Decoding helper functions
//===----------------------------------------------------------------------===//
/// EncodeToUTF8 - Encode the specified code point into a UTF8 stream. Return
/// true if it is an erroneous code point.
static bool EncodeToUTF8(unsigned CharValue,
SmallVectorImpl<char> &Result) {
// Number of bits in the value, ignoring leading zeros.
unsigned NumBits = 32-llvm::countl_zero(CharValue);
// Handle the leading byte, based on the number of bits in the value.
unsigned NumTrailingBytes;
if (NumBits <= 5+6) {
// Encoding is 0x110aaaaa 10bbbbbb
Result.push_back(char(0xC0 | (CharValue >> 6)));
NumTrailingBytes = 1;
} else if (NumBits <= 4+6+6) {
// Encoding is 0x1110aaaa 10bbbbbb 10cccccc
Result.push_back(char(0xE0 | (CharValue >> (6+6))));
NumTrailingBytes = 2;
// UTF-16 surrogate pair values are not valid code points.
if (CharValue >= 0xD800 && CharValue <= 0xDFFF)
return true;
// U+FDD0...U+FDEF are also reserved
if (CharValue >= 0xFDD0 && CharValue <= 0xFDEF)
return true;
} else if (NumBits <= 3+6+6+6) {
// Encoding is 0x11110aaa 10bbbbbb 10cccccc 10dddddd
Result.push_back(char(0xF0 | (CharValue >> (6+6+6))));
NumTrailingBytes = 3;
// Reject over-large code points. These cannot be encoded as UTF-16
// surrogate pairs, so UTF-32 doesn't allow them.
if (CharValue > 0x10FFFF)
return true;
} else {
return true; // UTF8 can encode these, but they aren't valid code points.
}
// Emit all of the trailing bytes.
while (NumTrailingBytes--)
Result.push_back(char(0x80 | (0x3F & (CharValue >> (NumTrailingBytes*6)))));
return false;
}
/// CLO8 - Return the number of leading ones in the specified 8-bit value.
static unsigned CLO8(unsigned char C) {
return llvm::countl_one(uint32_t(C) << 24);
}
/// isStartOfUTF8Character - Return true if this isn't a UTF8 continuation
/// character, which will be of the form 0b10XXXXXX
static bool isStartOfUTF8Character(unsigned char C) {
// RFC 2279: The octet values FE and FF never appear.
// RFC 3629: The octet values C0, C1, F5 to FF never appear.
return C <= 0x80 || (C >= 0xC2 && C < 0xF5);
}
/// validateUTF8CharacterAndAdvance - Given a pointer to the starting byte of a
/// UTF8 character, validate it and advance the lexer past it. This returns the
/// encoded character or ~0U if the encoding is invalid.
uint32_t swift::validateUTF8CharacterAndAdvance(const char *&Ptr,
const char *End) {
if (Ptr >= End)
return ~0U;
unsigned char CurByte = *Ptr++;
if (CurByte < 0x80)
return CurByte;
// Read the number of high bits set, which indicates the number of bytes in
// the character.
unsigned EncodedBytes = CLO8(CurByte);
// If this is 0b10XXXXXX, then it is a continuation character.
if (EncodedBytes == 1 ||
!isStartOfUTF8Character(CurByte)) {
// Skip until we get the start of another character. This is guaranteed to
// at least stop at the nul at the end of the buffer.
while (Ptr < End && !isStartOfUTF8Character(*Ptr))
++Ptr;
return ~0U;
}
// Drop the high bits indicating the # bytes of the result.
unsigned CharValue = (unsigned char)(CurByte << EncodedBytes) >> EncodedBytes;
// Read and validate the continuation bytes.
for (unsigned i = 1; i != EncodedBytes; ++i) {
if (Ptr >= End)
return ~0U;
CurByte = *Ptr;
// If the high bit isn't set or the second bit isn't clear, then this is not
// a continuation byte!
if (CurByte < 0x80 || CurByte >= 0xC0) return ~0U;
// Accumulate our result.
CharValue <<= 6;
CharValue |= CurByte & 0x3F;
++Ptr;
}
// UTF-16 surrogate pair values are not valid code points.
if (CharValue >= 0xD800 && CharValue <= 0xDFFF)
return ~0U;
// If we got here, we read the appropriate number of accumulated bytes.
// Verify that the encoding was actually minimal.
// Number of bits in the value, ignoring leading zeros.
unsigned NumBits = 32-llvm::countl_zero(CharValue);
if (NumBits <= 5+6)
return EncodedBytes == 2 ? CharValue : ~0U;
if (NumBits <= 4+6+6)
return EncodedBytes == 3 ? CharValue : ~0U;
return EncodedBytes == 4 ? CharValue : ~0U;
}
//===----------------------------------------------------------------------===//
// Setup and Helper Methods
//===----------------------------------------------------------------------===//
Lexer::Lexer(const PrincipalTag &, const LangOptions &LangOpts,
const SourceManager &SourceMgr, unsigned BufferID,
DiagnosticEngine *Diags, LexerMode LexMode,
HashbangMode HashbangAllowed,
CommentRetentionMode RetainComments)
: LangOpts(LangOpts), SourceMgr(SourceMgr), BufferID(BufferID),
LexMode(LexMode),
IsHashbangAllowed(HashbangAllowed == HashbangMode::Allowed),
RetainComments(RetainComments) {
if (Diags)
DiagQueue.emplace(*Diags, /*emitOnDestruction*/ false);
}
void Lexer::initialize(unsigned Offset, unsigned EndOffset) {
assert(Offset <= EndOffset);
// Initialize buffer pointers.
StringRef contents =
SourceMgr.extractText(SourceMgr.getRangeForBuffer(BufferID));
BufferStart = contents.data();
BufferEnd = contents.data() + contents.size();
assert(*BufferEnd == 0);
assert(BufferStart + Offset <= BufferEnd);
assert(BufferStart + EndOffset <= BufferEnd);
// Check for Unicode BOM at start of file (Only UTF-8 BOM supported now).
size_t BOMLength = contents.startswith("\xEF\xBB\xBF") ? 3 : 0;
// Keep information about existence of UTF-8 BOM for transparency source code
// editing with libSyntax.
ContentStart = BufferStart + BOMLength;
// Initialize code completion.
if (BufferID == SourceMgr.getIDEInspectionTargetBufferID()) {
const char *Ptr = BufferStart + SourceMgr.getIDEInspectionTargetOffset();
// If the pointer points to a null byte, it's the null byte that was
// inserted to mark the code completion token. If the IDE inspection offset
// points to a normal character, no code completion token should be
// inserted.
if (Ptr >= BufferStart && Ptr < BufferEnd && *Ptr == '\0') {
CodeCompletionPtr = Ptr;
}
}
ArtificialEOF = BufferStart + EndOffset;
CurPtr = BufferStart + Offset;
assert(NextToken.is(tok::NUM_TOKENS));
lexImpl();
assert((NextToken.isAtStartOfLine() || CurPtr != BufferStart) &&
"The token should be at the beginning of the line, "
"or we should be lexing from the middle of the buffer");
}
Lexer::Lexer(const LangOptions &Options, const SourceManager &SourceMgr,
unsigned BufferID, DiagnosticEngine *Diags, LexerMode LexMode,
HashbangMode HashbangAllowed,
CommentRetentionMode RetainComments)
: Lexer(PrincipalTag(), Options, SourceMgr, BufferID, Diags, LexMode,
HashbangAllowed, RetainComments) {
unsigned EndOffset = SourceMgr.getRangeForBuffer(BufferID).getByteLength();
initialize(/*Offset=*/0, EndOffset);
}
Lexer::Lexer(const LangOptions &Options, const SourceManager &SourceMgr,
unsigned BufferID, DiagnosticEngine *Diags, LexerMode LexMode,
HashbangMode HashbangAllowed, CommentRetentionMode RetainComments,
unsigned Offset, unsigned EndOffset)
: Lexer(PrincipalTag(), Options, SourceMgr, BufferID, Diags, LexMode,
HashbangAllowed, RetainComments) {
initialize(Offset, EndOffset);
}
Lexer::Lexer(const Lexer &Parent, State BeginState, State EndState,
bool EnableDiagnostics)
: Lexer(PrincipalTag(), Parent.LangOpts, Parent.SourceMgr, Parent.BufferID,
EnableDiagnostics ? Parent.getUnderlyingDiags() : nullptr,
Parent.LexMode,
Parent.IsHashbangAllowed
? HashbangMode::Allowed
: HashbangMode::Disallowed,
Parent.RetainComments) {
assert(BufferID == SourceMgr.findBufferContainingLoc(BeginState.Loc) &&
"state for the wrong buffer");
assert(BufferID == SourceMgr.findBufferContainingLoc(EndState.Loc) &&
"state for the wrong buffer");
unsigned Offset = SourceMgr.getLocOffsetInBuffer(BeginState.Loc, BufferID);
unsigned EndOffset = SourceMgr.getLocOffsetInBuffer(EndState.Loc, BufferID);
initialize(Offset, EndOffset);
}
InFlightDiagnostic Lexer::diagnose(const char *Loc, Diagnostic Diag) {
if (auto *Diags = getTokenDiags())
return Diags->diagnose(getSourceLoc(Loc), Diag);
return InFlightDiagnostic();
}
Token Lexer::getTokenAt(SourceLoc Loc) {
assert(BufferID == static_cast<unsigned>(
SourceMgr.findBufferContainingLoc(Loc)) &&
"location from the wrong buffer");
Lexer L(LangOpts, SourceMgr, BufferID, getUnderlyingDiags(), LexMode,
HashbangMode::Allowed, CommentRetentionMode::None);
L.restoreState(State(Loc));
return L.peekNextToken();
}
void Lexer::formToken(tok Kind, const char *TokStart) {
assert(CurPtr >= BufferStart &&
CurPtr <= BufferEnd && "Current pointer out of range!");
// When we are lexing a subrange from the middle of a file buffer, we will
// run past the end of the range, but will stay within the file. Check if
// we are past the imaginary EOF, and synthesize a tok::eof in this case.
if (Kind != tok::eof && TokStart >= ArtificialEOF) {
Kind = tok::eof;
}
unsigned CommentLength = 0;
if (RetainComments == CommentRetentionMode::AttachToNextToken) {
if (CommentStart) {
CommentLength = TokStart - CommentStart;
}
}
StringRef TokenText { TokStart, static_cast<size_t>(CurPtr - TokStart) };
NextToken.setToken(Kind, TokenText, CommentLength);
}
void Lexer::formEscapedIdentifierToken(const char *TokStart) {
assert(CurPtr - TokStart >= 3 && "escaped identifier must be longer than or equal 3 bytes");
assert(TokStart[0] == '`' && "escaped identifier starts with backtick");
assert(CurPtr[-1] == '`' && "escaped identifier ends with backtick");
formToken(tok::identifier, TokStart);
// If this token is at ArtificialEOF, it's forced to be tok::eof. Don't mark
// this as escaped-identifier in this case.
if (NextToken.is(tok::eof))
return;
NextToken.setEscapedIdentifier(true);
}
static void validateMultilineIndents(const Token &Str, DiagnosticEngine *Diags);
void Lexer::formStringLiteralToken(const char *TokStart,
bool IsMultilineString,
unsigned CustomDelimiterLen) {
formToken(tok::string_literal, TokStart);
if (NextToken.is(tok::eof))
return;
NextToken.setStringLiteral(IsMultilineString, CustomDelimiterLen);
auto *Diags = getTokenDiags();
if (IsMultilineString && Diags)
validateMultilineIndents(NextToken, Diags);
}
Lexer::State Lexer::getStateForBeginningOfTokenLoc(SourceLoc Loc) const {
const char *Ptr = getBufferPtrForSourceLoc(Loc);
// Skip whitespace backwards until we hit a newline. This is needed to
// correctly lex the token if it is at the beginning of the line.
while (Ptr >= ContentStart + 1) {
char C = Ptr[-1];
if (C == ' ' || C == '\t') {
--Ptr;
continue;
}
if (C == 0) {
// A NUL character can be either whitespace we diagnose or a code
// completion token.
if (Ptr - 1 == CodeCompletionPtr)
break;
--Ptr;
continue;
}
if (C == '\n' || C == '\r') {
--Ptr;
break;
}
break;
}
return State(SourceLoc(llvm::SMLoc::getFromPointer(Ptr)));
}
//===----------------------------------------------------------------------===//
// Lexer Subroutines
//===----------------------------------------------------------------------===//
static void diagnoseEmbeddedNul(DiagnosticEngine *Diags, const char *Ptr) {
assert(Ptr && "invalid source location");
assert(*Ptr == '\0' && "not an embedded null");
if (!Diags)
return;
SourceLoc NulLoc = Lexer::getSourceLoc(Ptr);
SourceLoc NulEndLoc = Lexer::getSourceLoc(Ptr+1);
Diags->diagnose(NulLoc, diag::lex_nul_character)
.fixItRemoveChars(NulLoc, NulEndLoc);
}
/// Advance \p CurPtr to the end of line or the end of file. Returns \c true
/// if it stopped at the end of line, \c false if it stopped at the end of file.
static bool advanceToEndOfLine(const char *&CurPtr, const char *BufferEnd,
const char *CodeCompletionPtr = nullptr,
DiagnosticEngine *Diags = nullptr) {
while (1) {
switch (*CurPtr++) {
case '\n':
case '\r':
--CurPtr;
return true; // If we found the end of the line, return.
default:
// If this is a "high" UTF-8 character, validate it.
if (Diags && (signed char)(CurPtr[-1]) < 0) {
--CurPtr;
const char *CharStart = CurPtr;
if (validateUTF8CharacterAndAdvance(CurPtr, BufferEnd) == ~0U)
Diags->diagnose(Lexer::getSourceLoc(CharStart),
diag::lex_invalid_utf8);
}
break; // Otherwise, eat other characters.
case 0:
if (CurPtr - 1 != BufferEnd) {
if (Diags && CurPtr - 1 != CodeCompletionPtr) {
// If this is a random nul character in the middle of a buffer, skip
// it as whitespace.
diagnoseEmbeddedNul(Diags, CurPtr - 1);
}
continue;
}
// Otherwise, the last line of the file does not have a newline.
--CurPtr;
return false;
}
}
}
void Lexer::skipToEndOfLine(bool EatNewline) {
bool isEOL =
advanceToEndOfLine(CurPtr, BufferEnd, CodeCompletionPtr, getTokenDiags());
if (EatNewline && isEOL) {
++CurPtr;
NextToken.setAtStartOfLine(true);
}
}
void Lexer::skipSlashSlashComment(bool EatNewline) {
assert(CurPtr[-1] == '/' && CurPtr[0] == '/' && "Not a // comment");
skipToEndOfLine(EatNewline);
}
void Lexer::skipHashbang(bool EatNewline) {
assert(CurPtr == ContentStart && CurPtr[0] == '#' && CurPtr[1] == '!' &&
"Not a hashbang");
skipToEndOfLine(EatNewline);
}
static bool skipToEndOfSlashStarComment(const char *&CurPtr,
const char *BufferEnd,
const char *CodeCompletionPtr = nullptr,
DiagnosticEngine *Diags = nullptr) {
const char *StartPtr = CurPtr-1;
assert(CurPtr[-1] == '/' && CurPtr[0] == '*' && "Not a /* comment");
// Make sure to advance over the * so that we don't incorrectly handle /*/ as
// the beginning and end of the comment.
++CurPtr;
// /**/ comments can be nested, keep track of how deep we've gone.
unsigned Depth = 1;
bool isMultiline = false;
while (1) {
switch (*CurPtr++) {
case '*':
// Check for a '*/'
if (*CurPtr == '/') {
++CurPtr;
if (--Depth == 0)
return isMultiline;
}
break;
case '/':
// Check for a '/*'
if (*CurPtr == '*') {
++CurPtr;
++Depth;
}
break;
case '\n':
case '\r':
isMultiline = true;
break;
default:
// If this is a "high" UTF-8 character, validate it.
if (Diags && (signed char)(CurPtr[-1]) < 0) {
--CurPtr;
const char *CharStart = CurPtr;
if (validateUTF8CharacterAndAdvance(CurPtr, BufferEnd) == ~0U)
Diags->diagnose(Lexer::getSourceLoc(CharStart),
diag::lex_invalid_utf8);
}
break; // Otherwise, eat other characters.
case 0:
if (CurPtr - 1 != BufferEnd) {
if (Diags && CurPtr - 1 != CodeCompletionPtr) {
// If this is a random nul character in the middle of a buffer, skip
// it as whitespace.
diagnoseEmbeddedNul(Diags, CurPtr - 1);
}
continue;
}
// Otherwise, we have an unterminated /* comment.
--CurPtr;
if (Diags) {
// Count how many levels deep we are.
llvm::SmallString<8> Terminator("*/");
while (--Depth != 0)
Terminator += "*/";
const char *EOL = (CurPtr[-1] == '\n') ? (CurPtr - 1) : CurPtr;
Diags
->diagnose(Lexer::getSourceLoc(EOL),
diag::lex_unterminated_block_comment)
.fixItInsert(Lexer::getSourceLoc(EOL), Terminator);
Diags->diagnose(Lexer::getSourceLoc(StartPtr), diag::lex_comment_start);
}
return isMultiline;
}
}
}
/// skipSlashStarComment - /**/ comments are skipped (treated as whitespace).
/// Note that (unlike in C) block comments can be nested.
void Lexer::skipSlashStarComment() {
bool isMultiline = skipToEndOfSlashStarComment(
CurPtr, BufferEnd, CodeCompletionPtr, getTokenDiags());
if (isMultiline)
NextToken.setAtStartOfLine(true);
}
static bool isValidIdentifierContinuationCodePoint(uint32_t c) {
if (c < 0x80)
return clang::isAsciiIdentifierContinue(c, /*dollar*/true);
// N1518: Recommendations for extended identifier characters for C and C++
// Proposed Annex X.1: Ranges of characters allowed
return c == 0x00A8 || c == 0x00AA || c == 0x00AD || c == 0x00AF
|| (c >= 0x00B2 && c <= 0x00B5) || (c >= 0x00B7 && c <= 0x00BA)
|| (c >= 0x00BC && c <= 0x00BE) || (c >= 0x00C0 && c <= 0x00D6)
|| (c >= 0x00D8 && c <= 0x00F6) || (c >= 0x00F8 && c <= 0x00FF)
|| (c >= 0x0100 && c <= 0x167F)
|| (c >= 0x1681 && c <= 0x180D)
|| (c >= 0x180F && c <= 0x1FFF)
|| (c >= 0x200B && c <= 0x200D)
|| (c >= 0x202A && c <= 0x202E)
|| (c >= 0x203F && c <= 0x2040)
|| c == 0x2054
|| (c >= 0x2060 && c <= 0x206F)
|| (c >= 0x2070 && c <= 0x218F)
|| (c >= 0x2460 && c <= 0x24FF)
|| (c >= 0x2776 && c <= 0x2793)
|| (c >= 0x2C00 && c <= 0x2DFF)
|| (c >= 0x2E80 && c <= 0x2FFF)
|| (c >= 0x3004 && c <= 0x3007)
|| (c >= 0x3021 && c <= 0x302F)
|| (c >= 0x3031 && c <= 0x303F)
|| (c >= 0x3040 && c <= 0xD7FF)
|| (c >= 0xF900 && c <= 0xFD3D)
|| (c >= 0xFD40 && c <= 0xFDCF)
|| (c >= 0xFDF0 && c <= 0xFE44)
|| (c >= 0xFE47 && c <= 0xFFF8)
|| (c >= 0x10000 && c <= 0x1FFFD)
|| (c >= 0x20000 && c <= 0x2FFFD)
|| (c >= 0x30000 && c <= 0x3FFFD)
|| (c >= 0x40000 && c <= 0x4FFFD)
|| (c >= 0x50000 && c <= 0x5FFFD)
|| (c >= 0x60000 && c <= 0x6FFFD)
|| (c >= 0x70000 && c <= 0x7FFFD)
|| (c >= 0x80000 && c <= 0x8FFFD)
|| (c >= 0x90000 && c <= 0x9FFFD)
|| (c >= 0xA0000 && c <= 0xAFFFD)
|| (c >= 0xB0000 && c <= 0xBFFFD)
|| (c >= 0xC0000 && c <= 0xCFFFD)
|| (c >= 0xD0000 && c <= 0xDFFFD)
|| (c >= 0xE0000 && c <= 0xEFFFD);
}
static bool isValidIdentifierStartCodePoint(uint32_t c) {
if (!isValidIdentifierContinuationCodePoint(c))
return false;
if (c < 0x80 && (isDigit(c) || c == '$'))
return false;
// N1518: Recommendations for extended identifier characters for C and C++
// Proposed Annex X.2: Ranges of characters disallowed initially
if ((c >= 0x0300 && c <= 0x036F) ||
(c >= 0x1DC0 && c <= 0x1DFF) ||
(c >= 0x20D0 && c <= 0x20FF) ||
(c >= 0xFE20 && c <= 0xFE2F))
return false;
return true;
}
static bool advanceIf(char const *&ptr, char const *end,
bool (*predicate)(uint32_t)) {
char const *next = ptr;
uint32_t c = validateUTF8CharacterAndAdvance(next, end);
if (c == ~0U)
return false;
if (predicate(c)) {
ptr = next;
return true;
}
return false;
}
static bool advanceIfValidStartOfIdentifier(char const *&ptr,
char const *end) {
return advanceIf(ptr, end, isValidIdentifierStartCodePoint);
}
static bool advanceIfValidContinuationOfIdentifier(char const *&ptr,
char const *end) {
return advanceIf(ptr, end, isValidIdentifierContinuationCodePoint);
}
static bool advanceIfValidStartOfOperator(char const *&ptr,
char const *end) {
return advanceIf(ptr, end, Identifier::isOperatorStartCodePoint);
}
static bool advanceIfValidContinuationOfOperator(char const *&ptr,
char const *end) {
return advanceIf(ptr, end, Identifier::isOperatorContinuationCodePoint);
}
bool Lexer::isIdentifier(StringRef string) {
if (string.empty()) return false;
char const *p = string.data(), *end = string.end();
if (!advanceIfValidStartOfIdentifier(p, end))
return false;
while (p < end && advanceIfValidContinuationOfIdentifier(p, end));
return p == end;
}
/// Determines if the given string is a valid operator identifier,
/// without escaping characters.
bool Lexer::isOperator(StringRef string) {
if (string.empty()) return false;
char const *p = string.data(), *end = string.end();
if (!advanceIfValidStartOfOperator(p, end))
return false;
while (p < end && advanceIfValidContinuationOfOperator(p, end));
return p == end;
}
tok Lexer::kindOfIdentifier(StringRef Str, bool InSILMode) {
#define SIL_KEYWORD(kw)
#define KEYWORD(kw) if (Str == #kw) return tok::kw_##kw;
#include "swift/AST/TokenKinds.def"
// SIL keywords are only active in SIL mode.
if (InSILMode) {
#define SIL_KEYWORD(kw) if (Str == #kw) return tok::kw_##kw;
#include "swift/AST/TokenKinds.def"
}
return tok::identifier;
}
/// lexIdentifier - Match [a-zA-Z_][a-zA-Z_$0-9]*
void Lexer::lexIdentifier() {
const char *TokStart = CurPtr-1;
CurPtr = TokStart;
bool didStart = advanceIfValidStartOfIdentifier(CurPtr, BufferEnd);
assert(didStart && "Unexpected start");
(void) didStart;
// Lex [a-zA-Z_$0-9[[:XID_Continue:]]]*
while (advanceIfValidContinuationOfIdentifier(CurPtr, BufferEnd));
tok Kind = kindOfIdentifier(StringRef(TokStart, CurPtr-TokStart),
LexMode == LexerMode::SIL);
return formToken(Kind, TokStart);
}
/// lexHash - Handle #], #! for shebangs, and the family of #identifiers.
void Lexer::lexHash() {
const char *TokStart = CurPtr-1;
// Scan for [a-zA-Z]+ to see what we match.
const char *tmpPtr = CurPtr;
if (clang::isAsciiIdentifierStart(*tmpPtr)) {
do {
++tmpPtr;
} while (clang::isAsciiIdentifierContinue(*tmpPtr));
}
// Map the character sequence onto
tok Kind = llvm::StringSwitch<tok>(StringRef(CurPtr, tmpPtr-CurPtr))
#define POUND_KEYWORD(id) \
.Case(#id, tok::pound_##id)
#include "swift/AST/TokenKinds.def"
.Default(tok::pound);
// If we found '#assert' but that experimental feature is not enabled,
// treat it as '#'.
if (Kind == tok::pound_assert && !LangOpts.hasFeature(Feature::StaticAssert))
Kind = tok::pound;
// If we didn't find a match, then just return tok::pound. This is highly
// dubious in terms of error recovery, but is useful for code completion and
// SIL parsing.
if (Kind == tok::pound)
return formToken(tok::pound, TokStart);
// If we found something specific, return it.
CurPtr = tmpPtr;
return formToken(Kind, TokStart);
}
/// Is the operator beginning at the given character "left-bound"?
static bool isLeftBound(const char *tokBegin, const char *bufferBegin) {
// The first character in the file is not left-bound.
if (tokBegin == bufferBegin) return false;
switch (tokBegin[-1]) {
case ' ': case '\r': case '\n': case '\t': // whitespace
case '(': case '[': case '{': // opening delimiters
case ',': case ';': case ':': // expression separators
case '\0': // whitespace / last char in file
return false;
case '/':
if (tokBegin - 1 != bufferBegin && tokBegin[-2] == '*')
return false; // End of a slash-star comment, so whitespace.
else
return true;
case '\xA0':
if (tokBegin - 1 != bufferBegin && tokBegin[-2] == '\xC2')
return false; // Non-breaking whitespace (U+00A0)
else
return true;
default:
return true;
}
}
/// Is the operator ending at the given character (actually one past the end)
/// "right-bound"?
///
/// The code-completion point is considered right-bound.
static bool isRightBound(const char *tokEnd, bool isLeftBound,
const char *codeCompletionPtr) {
switch (*tokEnd) {
case ' ': case '\r': case '\n': case '\t': // whitespace
case ')': case ']': case '}': // closing delimiters
case ',': case ';': case ':': // expression separators
return false;
case '\0':
if (tokEnd == codeCompletionPtr) // code-completion
return true;
return false; // whitespace / last char in file
case '.':
// Prefer the '^' in "x^.y" to be a postfix op, not binary, but the '^' in
// "^.y" to be a prefix op, not binary.
return !isLeftBound;
case '/':
// A following comment counts as whitespace, so this token is not right bound.
if (tokEnd[1] == '/' || tokEnd[1] == '*')
return false;
else
return true;
case '\xC2':
if (tokEnd[1] == '\xA0')
return false; // Non-breaking whitespace (U+00A0)
else
return true;
default:
return true;
}
}
static bool rangeContainsPlaceholderEnd(const char *CurPtr,
const char *End) {
for (auto SubStr = CurPtr; SubStr != End - 1; ++SubStr) {
if (SubStr[0] == '\n') {
return false;
}
if (SubStr[0] == '#' && SubStr[1] == '>') {
return true;
}
}
return false;
}
/// lexOperatorIdentifier - Match identifiers formed out of punctuation.
void Lexer::lexOperatorIdentifier() {
const char *TokStart = CurPtr-1;
CurPtr = TokStart;
bool didStart = advanceIfValidStartOfOperator(CurPtr, BufferEnd);
assert(didStart && "unexpected operator start");
(void) didStart;
do {
if (CurPtr != BufferEnd && InSILBody &&
(*CurPtr == '!' || *CurPtr == '?'))
// When parsing SIL body, '!' and '?' are special token and can't be
// in the middle of an operator.
break;
// '.' cannot appear in the middle of an operator unless the operator
// started with a '.'.
if (*CurPtr == '.' && *TokStart != '.')
break;
if (Identifier::isEditorPlaceholder(StringRef(CurPtr, BufferEnd-CurPtr)) &&
rangeContainsPlaceholderEnd(CurPtr + 2, BufferEnd)) {
break;
}
// If we are lexing a `/.../` regex literal, we don't consider `/` to be an
// operator character.
if (ForwardSlashRegexMode != LexerForwardSlashRegexMode::None &&
*CurPtr == '/') {
break;
}
} while (advanceIfValidContinuationOfOperator(CurPtr, BufferEnd));
if (CurPtr-TokStart > 2) {
// If there is a "//" or "/*" in the middle of an identifier token,
// it starts a comment.
for (auto Ptr = TokStart+1; Ptr != CurPtr-1; ++Ptr) {
if (Ptr[0] == '/' && (Ptr[1] == '/' || Ptr[1] == '*')) {
CurPtr = Ptr;
break;
}
}
}
// Decide between the binary, prefix, and postfix cases.
// It's binary if either both sides are bound or both sides are not bound.
// Otherwise, it's postfix if left-bound and prefix if right-bound.
bool leftBound = isLeftBound(TokStart, ContentStart);
bool rightBound = isRightBound(CurPtr, leftBound, CodeCompletionPtr);
// Match various reserved words.
if (CurPtr-TokStart == 1) {
switch (TokStart[0]) {
case '=':
// Refrain from emitting this message in operator name position.
if (NextToken.isNot(tok::kw_operator) && leftBound != rightBound) {
auto d = diagnose(TokStart, diag::lex_unary_equal);
if (leftBound)
d.fixItInsert(getSourceLoc(TokStart), " ");
else
d.fixItInsert(getSourceLoc(TokStart+1), " ");
}
// always emit 'tok::equal' to avoid trickle down parse errors
return formToken(tok::equal, TokStart);
case '&':
if (leftBound == rightBound || leftBound)
break;
return formToken(tok::amp_prefix, TokStart);
case '.': {
if (leftBound == rightBound)
return formToken(tok::period, TokStart);
if (rightBound)
return formToken(tok::period_prefix, TokStart);
// If left bound but not right bound, handle some likely situations.
// If there is just some horizontal whitespace before the next token, its
// addition is probably incorrect.
const char *AfterHorzWhitespace = CurPtr;
while (*AfterHorzWhitespace == ' ' || *AfterHorzWhitespace == '\t')
++AfterHorzWhitespace;
// First, when we are code completing "x. <ESC>", then make sure to return
// a tok::period, since that is what the user is wanting to know about.
if (*AfterHorzWhitespace == '\0' &&
AfterHorzWhitespace == CodeCompletionPtr) {
diagnose(TokStart, diag::expected_member_name);
return formToken(tok::period, TokStart);
}
if (isRightBound(AfterHorzWhitespace, leftBound, CodeCompletionPtr) &&
// Don't consider comments to be this. A leading slash is probably
// either // or /* and most likely occurs just in our testsuite for
// expected-error lines.
*AfterHorzWhitespace != '/') {
diagnose(TokStart, diag::extra_whitespace_period)
.fixItRemoveChars(getSourceLoc(CurPtr),
getSourceLoc(AfterHorzWhitespace));
return formToken(tok::period, TokStart);
}
// Otherwise, it is probably a missing member.
diagnose(TokStart, diag::expected_member_name);
return formToken(tok::unknown, TokStart);
}
case '?':
if (leftBound)
return formToken(tok::question_postfix, TokStart);
return formToken(tok::question_infix, TokStart);
}
} else if (CurPtr-TokStart == 2) {
switch ((TokStart[0] << 8) | TokStart[1]) {
case ('-' << 8) | '>': // ->
return formToken(tok::arrow, TokStart);
case ('*' << 8) | '/': // */
diagnose(TokStart, diag::lex_unexpected_block_comment_end);
return formToken(tok::unknown, TokStart);
}
} else {
// Verify there is no "*/" in the middle of the identifier token, we reject
// it as potentially ending a block comment.
auto Pos = StringRef(TokStart, CurPtr-TokStart).find("*/");
if (Pos != StringRef::npos) {
diagnose(TokStart+Pos, diag::lex_unexpected_block_comment_end);
return formToken(tok::unknown, TokStart);
}
}
if (leftBound == rightBound)
return formToken(leftBound ? tok::oper_binary_unspaced :
tok::oper_binary_spaced, TokStart);
return formToken(leftBound ? tok::oper_postfix : tok::oper_prefix, TokStart);
}
/// lexDollarIdent - Match $[0-9a-zA-Z_$]+
void Lexer::lexDollarIdent() {
const char *tokStart = CurPtr-1;
assert(*tokStart == '$');
// In a SIL function body, '$' is a token by itself, except it's a SIL global
// name. SIL global identifiers may start with a '$', e.g. @$S1m3fooyyF.
if (InSILBody && NextToken.getKind() != tok::at_sign)
return formToken(tok::sil_dollar, tokStart);
bool isAllDigits = true;
while (true) {
if (isDigit(*CurPtr)) {
++CurPtr;
continue;
} else if (advanceIfValidContinuationOfIdentifier(CurPtr, BufferEnd)) {
isAllDigits = false;
continue;
}
break;
}
// If there is a standalone '$', treat it like an identifier.
if (CurPtr == tokStart + 1) {
return formToken(tok::identifier, tokStart);
}
if (!isAllDigits) {
return formToken(tok::identifier, tokStart);
} else {
return formToken(tok::dollarident, tokStart);
}
}
enum class ExpectedDigitKind : unsigned { Binary, Octal, Decimal, Hex };
void Lexer::lexHexNumber() {
// We assume we're starting from the 'x' in a '0x...' floating-point literal.
assert(*CurPtr == 'x' && "not a hex literal");
const char *TokStart = CurPtr-1;
assert(*TokStart == '0' && "not a hex literal");
auto expected_digit = [&]() {
while (advanceIfValidContinuationOfIdentifier(CurPtr, BufferEnd));
return formToken(tok::unknown, TokStart);
};
auto expected_hex_digit = [&](const char *loc) {
diagnose(loc, diag::lex_invalid_digit_in_int_literal, StringRef(loc, 1),
(unsigned)ExpectedDigitKind::Hex);
return expected_digit();
};
// 0x[0-9a-fA-F][0-9a-fA-F_]*
++CurPtr;
if (!isHexDigit(*CurPtr))
return expected_hex_digit(CurPtr);
while (isHexDigit(*CurPtr) || *CurPtr == '_')
++CurPtr;
if (*CurPtr != '.' && *CurPtr != 'p' && *CurPtr != 'P') {
auto tmp = CurPtr;
if (advanceIfValidContinuationOfIdentifier(CurPtr, BufferEnd))
return expected_hex_digit(tmp);
else
return formToken(tok::integer_literal, TokStart);
}
const char *PtrOnDot = nullptr;
// (\.[0-9A-Fa-f][0-9A-Fa-f_]*)?
if (*CurPtr == '.') {
PtrOnDot = CurPtr;
++CurPtr;
// If the character after the '.' is not a digit, assume we have an int