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llvm-project/clang/lib/Format/FormatTokenLexer.cpp

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//===--- FormatTokenLexer.cpp - Lex FormatTokens -------------*- C++ ----*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file implements FormatTokenLexer, which tokenizes a source file
/// into a FormatToken stream suitable for ClangFormat.
///
//===----------------------------------------------------------------------===//
#include "FormatTokenLexer.h"
#include "FormatToken.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Format/Format.h"
#include "llvm/Support/Regex.h"
namespace clang {
namespace format {
FormatTokenLexer::FormatTokenLexer(const SourceManager &SourceMgr, FileID ID,
const FormatStyle &Style,
encoding::Encoding Encoding)
: FormatTok(nullptr), IsFirstToken(true), StateStack({LexerState::NORMAL}),
Column(0), TrailingWhitespace(0), SourceMgr(SourceMgr), ID(ID),
Style(Style), IdentTable(getFormattingLangOpts(Style)),
Keywords(IdentTable), Encoding(Encoding), FirstInLineIndex(0),
FormattingDisabled(false), MacroBlockBeginRegex(Style.MacroBlockBegin),
MacroBlockEndRegex(Style.MacroBlockEnd) {
Lex.reset(new Lexer(ID, SourceMgr.getBuffer(ID), SourceMgr,
getFormattingLangOpts(Style)));
Lex->SetKeepWhitespaceMode(true);
for (const std::string &ForEachMacro : Style.ForEachMacros)
ForEachMacros.push_back(&IdentTable.get(ForEachMacro));
std::sort(ForEachMacros.begin(), ForEachMacros.end());
}
ArrayRef<FormatToken *> FormatTokenLexer::lex() {
assert(Tokens.empty());
assert(FirstInLineIndex == 0);
do {
Tokens.push_back(getNextToken());
if (Style.Language == FormatStyle::LK_JavaScript) {
tryParseJSRegexLiteral();
handleTemplateStrings();
}
tryMergePreviousTokens();
if (Tokens.back()->NewlinesBefore > 0 || Tokens.back()->IsMultiline)
FirstInLineIndex = Tokens.size() - 1;
} while (Tokens.back()->Tok.isNot(tok::eof));
return Tokens;
}
void FormatTokenLexer::tryMergePreviousTokens() {
if (tryMerge_TMacro())
return;
if (tryMergeConflictMarkers())
return;
if (tryMergeLessLess())
return;
if (Style.Language == FormatStyle::LK_JavaScript) {
static const tok::TokenKind JSIdentity[] = {tok::equalequal, tok::equal};
static const tok::TokenKind JSNotIdentity[] = {tok::exclaimequal,
tok::equal};
static const tok::TokenKind JSShiftEqual[] = {tok::greater, tok::greater,
tok::greaterequal};
static const tok::TokenKind JSRightArrow[] = {tok::equal, tok::greater};
// FIXME: Investigate what token type gives the correct operator priority.
if (tryMergeTokens(JSIdentity, TT_BinaryOperator))
return;
if (tryMergeTokens(JSNotIdentity, TT_BinaryOperator))
return;
if (tryMergeTokens(JSShiftEqual, TT_BinaryOperator))
return;
if (tryMergeTokens(JSRightArrow, TT_JsFatArrow))
return;
}
}
bool FormatTokenLexer::tryMergeLessLess() {
// Merge X,less,less,Y into X,lessless,Y unless X or Y is less.
if (Tokens.size() < 3)
return false;
bool FourthTokenIsLess = false;
if (Tokens.size() > 3)
FourthTokenIsLess = (Tokens.end() - 4)[0]->is(tok::less);
auto First = Tokens.end() - 3;
if (First[2]->is(tok::less) || First[1]->isNot(tok::less) ||
First[0]->isNot(tok::less) || FourthTokenIsLess)
return false;
// Only merge if there currently is no whitespace between the two "<".
if (First[1]->WhitespaceRange.getBegin() !=
First[1]->WhitespaceRange.getEnd())
return false;
First[0]->Tok.setKind(tok::lessless);
First[0]->TokenText = "<<";
First[0]->ColumnWidth += 1;
Tokens.erase(Tokens.end() - 2);
return true;
}
bool FormatTokenLexer::tryMergeTokens(ArrayRef<tok::TokenKind> Kinds,
TokenType NewType) {
if (Tokens.size() < Kinds.size())
return false;
SmallVectorImpl<FormatToken *>::const_iterator First =
Tokens.end() - Kinds.size();
if (!First[0]->is(Kinds[0]))
return false;
unsigned AddLength = 0;
for (unsigned i = 1; i < Kinds.size(); ++i) {
if (!First[i]->is(Kinds[i]) ||
First[i]->WhitespaceRange.getBegin() !=
First[i]->WhitespaceRange.getEnd())
return false;
AddLength += First[i]->TokenText.size();
}
Tokens.resize(Tokens.size() - Kinds.size() + 1);
First[0]->TokenText = StringRef(First[0]->TokenText.data(),
First[0]->TokenText.size() + AddLength);
First[0]->ColumnWidth += AddLength;
First[0]->Type = NewType;
return true;
}
// Returns \c true if \p Tok can only be followed by an operand in JavaScript.
bool FormatTokenLexer::precedesOperand(FormatToken *Tok) {
// NB: This is not entirely correct, as an r_paren can introduce an operand
// location in e.g. `if (foo) /bar/.exec(...);`. That is a rare enough
// corner case to not matter in practice, though.
return Tok->isOneOf(tok::period, tok::l_paren, tok::comma, tok::l_brace,
tok::r_brace, tok::l_square, tok::semi, tok::exclaim,
tok::colon, tok::question, tok::tilde) ||
Tok->isOneOf(tok::kw_return, tok::kw_do, tok::kw_case, tok::kw_throw,
tok::kw_else, tok::kw_new, tok::kw_delete, tok::kw_void,
tok::kw_typeof, Keywords.kw_instanceof, Keywords.kw_in) ||
Tok->isBinaryOperator();
}
bool FormatTokenLexer::canPrecedeRegexLiteral(FormatToken *Prev) {
if (!Prev)
return true;
// Regex literals can only follow after prefix unary operators, not after
// postfix unary operators. If the '++' is followed by a non-operand
// introducing token, the slash here is the operand and not the start of a
// regex.
// `!` is an unary prefix operator, but also a post-fix operator that casts
// away nullability, so the same check applies.
if (Prev->isOneOf(tok::plusplus, tok::minusminus, tok::exclaim))
return (Tokens.size() < 3 || precedesOperand(Tokens[Tokens.size() - 3]));
// The previous token must introduce an operand location where regex
// literals can occur.
if (!precedesOperand(Prev))
return false;
return true;
}
// Tries to parse a JavaScript Regex literal starting at the current token,
// if that begins with a slash and is in a location where JavaScript allows
// regex literals. Changes the current token to a regex literal and updates
// its text if successful.
void FormatTokenLexer::tryParseJSRegexLiteral() {
FormatToken *RegexToken = Tokens.back();
if (!RegexToken->isOneOf(tok::slash, tok::slashequal))
return;
FormatToken *Prev = nullptr;
for (auto I = Tokens.rbegin() + 1, E = Tokens.rend(); I != E; ++I) {
// NB: Because previous pointers are not initialized yet, this cannot use
// Token.getPreviousNonComment.
if ((*I)->isNot(tok::comment)) {
Prev = *I;
break;
}
}
if (!canPrecedeRegexLiteral(Prev))
return;
// 'Manually' lex ahead in the current file buffer.
const char *Offset = Lex->getBufferLocation();
const char *RegexBegin = Offset - RegexToken->TokenText.size();
StringRef Buffer = Lex->getBuffer();
bool InCharacterClass = false;
bool HaveClosingSlash = false;
for (; !HaveClosingSlash && Offset != Buffer.end(); ++Offset) {
// Regular expressions are terminated with a '/', which can only be
// escaped using '\' or a character class between '[' and ']'.
// See http://www.ecma-international.org/ecma-262/5.1/#sec-7.8.5.
switch (*Offset) {
case '\\':
// Skip the escaped character.
++Offset;
break;
case '[':
InCharacterClass = true;
break;
case ']':
InCharacterClass = false;
break;
case '/':
if (!InCharacterClass)
HaveClosingSlash = true;
break;
}
}
RegexToken->Type = TT_RegexLiteral;
// Treat regex literals like other string_literals.
RegexToken->Tok.setKind(tok::string_literal);
RegexToken->TokenText = StringRef(RegexBegin, Offset - RegexBegin);
RegexToken->ColumnWidth = RegexToken->TokenText.size();
resetLexer(SourceMgr.getFileOffset(Lex->getSourceLocation(Offset)));
}
void FormatTokenLexer::handleTemplateStrings() {
FormatToken *BacktickToken = Tokens.back();
if (BacktickToken->is(tok::l_brace)) {
StateStack.push(LexerState::NORMAL);
return;
}
if (BacktickToken->is(tok::r_brace)) {
if (StateStack.size() == 1)
return;
StateStack.pop();
if (StateStack.top() != LexerState::TEMPLATE_STRING)
return;
// If back in TEMPLATE_STRING, fallthrough and continue parsing the
} else if (BacktickToken->is(tok::unknown) &&
BacktickToken->TokenText == "`") {
StateStack.push(LexerState::TEMPLATE_STRING);
} else {
return; // Not actually a template
}
// 'Manually' lex ahead in the current file buffer.
const char *Offset = Lex->getBufferLocation();
const char *TmplBegin = Offset - BacktickToken->TokenText.size(); // at "`"
for (; Offset != Lex->getBuffer().end(); ++Offset) {
if (Offset[0] == '`') {
StateStack.pop();
break;
}
if (Offset[0] == '\\') {
++Offset; // Skip the escaped character.
} else if (Offset + 1 < Lex->getBuffer().end() && Offset[0] == '$' &&
Offset[1] == '{') {
// '${' introduces an expression interpolation in the template string.
StateStack.push(LexerState::NORMAL);
++Offset;
break;
}
}
StringRef LiteralText(TmplBegin, Offset - TmplBegin + 1);
BacktickToken->Type = TT_TemplateString;
BacktickToken->Tok.setKind(tok::string_literal);
BacktickToken->TokenText = LiteralText;
// Adjust width for potentially multiline string literals.
size_t FirstBreak = LiteralText.find('\n');
StringRef FirstLineText = FirstBreak == StringRef::npos
? LiteralText
: LiteralText.substr(0, FirstBreak);
BacktickToken->ColumnWidth = encoding::columnWidthWithTabs(
FirstLineText, BacktickToken->OriginalColumn, Style.TabWidth, Encoding);
size_t LastBreak = LiteralText.rfind('\n');
if (LastBreak != StringRef::npos) {
BacktickToken->IsMultiline = true;
unsigned StartColumn = 0; // The template tail spans the entire line.
BacktickToken->LastLineColumnWidth = encoding::columnWidthWithTabs(
LiteralText.substr(LastBreak + 1, LiteralText.size()), StartColumn,
Style.TabWidth, Encoding);
}
SourceLocation loc = Offset < Lex->getBuffer().end()
? Lex->getSourceLocation(Offset + 1)
: SourceMgr.getLocForEndOfFile(ID);
resetLexer(SourceMgr.getFileOffset(loc));
}
bool FormatTokenLexer::tryMerge_TMacro() {
if (Tokens.size() < 4)
return false;
FormatToken *Last = Tokens.back();
if (!Last->is(tok::r_paren))
return false;
FormatToken *String = Tokens[Tokens.size() - 2];
if (!String->is(tok::string_literal) || String->IsMultiline)
return false;
if (!Tokens[Tokens.size() - 3]->is(tok::l_paren))
return false;
FormatToken *Macro = Tokens[Tokens.size() - 4];
if (Macro->TokenText != "_T")
return false;
const char *Start = Macro->TokenText.data();
const char *End = Last->TokenText.data() + Last->TokenText.size();
String->TokenText = StringRef(Start, End - Start);
String->IsFirst = Macro->IsFirst;
String->LastNewlineOffset = Macro->LastNewlineOffset;
String->WhitespaceRange = Macro->WhitespaceRange;
String->OriginalColumn = Macro->OriginalColumn;
String->ColumnWidth = encoding::columnWidthWithTabs(
String->TokenText, String->OriginalColumn, Style.TabWidth, Encoding);
String->NewlinesBefore = Macro->NewlinesBefore;
String->HasUnescapedNewline = Macro->HasUnescapedNewline;
Tokens.pop_back();
Tokens.pop_back();
Tokens.pop_back();
Tokens.back() = String;
return true;
}
bool FormatTokenLexer::tryMergeConflictMarkers() {
if (Tokens.back()->NewlinesBefore == 0 && Tokens.back()->isNot(tok::eof))
return false;
// Conflict lines look like:
// <marker> <text from the vcs>
// For example:
// >>>>>>> /file/in/file/system at revision 1234
//
// We merge all tokens in a line that starts with a conflict marker
// into a single token with a special token type that the unwrapped line
// parser will use to correctly rebuild the underlying code.
FileID ID;
// Get the position of the first token in the line.
unsigned FirstInLineOffset;
std::tie(ID, FirstInLineOffset) = SourceMgr.getDecomposedLoc(
Tokens[FirstInLineIndex]->getStartOfNonWhitespace());
StringRef Buffer = SourceMgr.getBuffer(ID)->getBuffer();
// Calculate the offset of the start of the current line.
auto LineOffset = Buffer.rfind('\n', FirstInLineOffset);
if (LineOffset == StringRef::npos) {
LineOffset = 0;
} else {
++LineOffset;
}
auto FirstSpace = Buffer.find_first_of(" \n", LineOffset);
StringRef LineStart;
if (FirstSpace == StringRef::npos) {
LineStart = Buffer.substr(LineOffset);
} else {
LineStart = Buffer.substr(LineOffset, FirstSpace - LineOffset);
}
TokenType Type = TT_Unknown;
if (LineStart == "<<<<<<<" || LineStart == ">>>>") {
Type = TT_ConflictStart;
} else if (LineStart == "|||||||" || LineStart == "=======" ||
LineStart == "====") {
Type = TT_ConflictAlternative;
} else if (LineStart == ">>>>>>>" || LineStart == "<<<<") {
Type = TT_ConflictEnd;
}
if (Type != TT_Unknown) {
FormatToken *Next = Tokens.back();
Tokens.resize(FirstInLineIndex + 1);
// We do not need to build a complete token here, as we will skip it
// during parsing anyway (as we must not touch whitespace around conflict
// markers).
Tokens.back()->Type = Type;
Tokens.back()->Tok.setKind(tok::kw___unknown_anytype);
Tokens.push_back(Next);
return true;
}
return false;
}
FormatToken *FormatTokenLexer::getStashedToken() {
// Create a synthesized second '>' or '<' token.
Token Tok = FormatTok->Tok;
StringRef TokenText = FormatTok->TokenText;
unsigned OriginalColumn = FormatTok->OriginalColumn;
FormatTok = new (Allocator.Allocate()) FormatToken;
FormatTok->Tok = Tok;
SourceLocation TokLocation =
FormatTok->Tok.getLocation().getLocWithOffset(Tok.getLength() - 1);
FormatTok->Tok.setLocation(TokLocation);
FormatTok->WhitespaceRange = SourceRange(TokLocation, TokLocation);
FormatTok->TokenText = TokenText;
FormatTok->ColumnWidth = 1;
FormatTok->OriginalColumn = OriginalColumn + 1;
return FormatTok;
}
FormatToken *FormatTokenLexer::getNextToken() {
if (StateStack.top() == LexerState::TOKEN_STASHED) {
StateStack.pop();
return getStashedToken();
}
FormatTok = new (Allocator.Allocate()) FormatToken;
readRawToken(*FormatTok);
SourceLocation WhitespaceStart =
FormatTok->Tok.getLocation().getLocWithOffset(-TrailingWhitespace);
FormatTok->IsFirst = IsFirstToken;
IsFirstToken = false;
// Consume and record whitespace until we find a significant token.
unsigned WhitespaceLength = TrailingWhitespace;
while (FormatTok->Tok.is(tok::unknown)) {
StringRef Text = FormatTok->TokenText;
auto EscapesNewline = [&](int pos) {
// A '\r' here is just part of '\r\n'. Skip it.
if (pos >= 0 && Text[pos] == '\r')
--pos;
// See whether there is an odd number of '\' before this.
unsigned count = 0;
for (; pos >= 0; --pos, ++count)
if (Text[pos] != '\\')
break;
return count & 1;
};
// FIXME: This miscounts tok:unknown tokens that are not just
// whitespace, e.g. a '`' character.
for (int i = 0, e = Text.size(); i != e; ++i) {
switch (Text[i]) {
case '\n':
++FormatTok->NewlinesBefore;
FormatTok->HasUnescapedNewline = !EscapesNewline(i - 1);
FormatTok->LastNewlineOffset = WhitespaceLength + i + 1;
Column = 0;
break;
case '\r':
FormatTok->LastNewlineOffset = WhitespaceLength + i + 1;
Column = 0;
break;
case '\f':
case '\v':
Column = 0;
break;
case ' ':
++Column;
break;
case '\t':
Column += Style.TabWidth - Column % Style.TabWidth;
break;
case '\\':
if (i + 1 == e || (Text[i + 1] != '\r' && Text[i + 1] != '\n'))
FormatTok->Type = TT_ImplicitStringLiteral;
break;
default:
FormatTok->Type = TT_ImplicitStringLiteral;
break;
}
if (FormatTok->Type == TT_ImplicitStringLiteral)
break;
}
if (FormatTok->is(TT_ImplicitStringLiteral))
break;
WhitespaceLength += FormatTok->Tok.getLength();
readRawToken(*FormatTok);
}
// In case the token starts with escaped newlines, we want to
// take them into account as whitespace - this pattern is quite frequent
// in macro definitions.
// FIXME: Add a more explicit test.
while (FormatTok->TokenText.size() > 1 && FormatTok->TokenText[0] == '\\' &&
FormatTok->TokenText[1] == '\n') {
++FormatTok->NewlinesBefore;
WhitespaceLength += 2;
FormatTok->LastNewlineOffset = 2;
Column = 0;
FormatTok->TokenText = FormatTok->TokenText.substr(2);
}
FormatTok->WhitespaceRange = SourceRange(
WhitespaceStart, WhitespaceStart.getLocWithOffset(WhitespaceLength));
FormatTok->OriginalColumn = Column;
TrailingWhitespace = 0;
if (FormatTok->Tok.is(tok::comment)) {
// FIXME: Add the trimmed whitespace to Column.
StringRef UntrimmedText = FormatTok->TokenText;
FormatTok->TokenText = FormatTok->TokenText.rtrim(" \t\v\f");
TrailingWhitespace = UntrimmedText.size() - FormatTok->TokenText.size();
} else if (FormatTok->Tok.is(tok::raw_identifier)) {
IdentifierInfo &Info = IdentTable.get(FormatTok->TokenText);
FormatTok->Tok.setIdentifierInfo(&Info);
FormatTok->Tok.setKind(Info.getTokenID());
if (Style.Language == FormatStyle::LK_Java &&
FormatTok->isOneOf(tok::kw_struct, tok::kw_union, tok::kw_delete,
tok::kw_operator)) {
FormatTok->Tok.setKind(tok::identifier);
FormatTok->Tok.setIdentifierInfo(nullptr);
} else if (Style.Language == FormatStyle::LK_JavaScript &&
FormatTok->isOneOf(tok::kw_struct, tok::kw_union,
tok::kw_operator)) {
FormatTok->Tok.setKind(tok::identifier);
FormatTok->Tok.setIdentifierInfo(nullptr);
}
} else if (FormatTok->Tok.is(tok::greatergreater)) {
FormatTok->Tok.setKind(tok::greater);
FormatTok->TokenText = FormatTok->TokenText.substr(0, 1);
++Column;
StateStack.push(LexerState::TOKEN_STASHED);
} else if (FormatTok->Tok.is(tok::lessless)) {
FormatTok->Tok.setKind(tok::less);
FormatTok->TokenText = FormatTok->TokenText.substr(0, 1);
++Column;
StateStack.push(LexerState::TOKEN_STASHED);
}
// Now FormatTok is the next non-whitespace token.
StringRef Text = FormatTok->TokenText;
size_t FirstNewlinePos = Text.find('\n');
if (FirstNewlinePos == StringRef::npos) {
// FIXME: ColumnWidth actually depends on the start column, we need to
// take this into account when the token is moved.
FormatTok->ColumnWidth =
encoding::columnWidthWithTabs(Text, Column, Style.TabWidth, Encoding);
Column += FormatTok->ColumnWidth;
} else {
FormatTok->IsMultiline = true;
// FIXME: ColumnWidth actually depends on the start column, we need to
// take this into account when the token is moved.
FormatTok->ColumnWidth = encoding::columnWidthWithTabs(
Text.substr(0, FirstNewlinePos), Column, Style.TabWidth, Encoding);
// The last line of the token always starts in column 0.
// Thus, the length can be precomputed even in the presence of tabs.
FormatTok->LastLineColumnWidth = encoding::columnWidthWithTabs(
Text.substr(Text.find_last_of('\n') + 1), 0, Style.TabWidth, Encoding);
Column = FormatTok->LastLineColumnWidth;
}
if (Style.IsCpp()) {
if (!(Tokens.size() > 0 && Tokens.back()->Tok.getIdentifierInfo() &&
Tokens.back()->Tok.getIdentifierInfo()->getPPKeywordID() ==
tok::pp_define) &&
std::find(ForEachMacros.begin(), ForEachMacros.end(),
FormatTok->Tok.getIdentifierInfo()) != ForEachMacros.end()) {
FormatTok->Type = TT_ForEachMacro;
} else if (FormatTok->is(tok::identifier)) {
if (MacroBlockBeginRegex.match(Text)) {
FormatTok->Type = TT_MacroBlockBegin;
} else if (MacroBlockEndRegex.match(Text)) {
FormatTok->Type = TT_MacroBlockEnd;
}
}
}
return FormatTok;
}
void FormatTokenLexer::readRawToken(FormatToken &Tok) {
Lex->LexFromRawLexer(Tok.Tok);
Tok.TokenText = StringRef(SourceMgr.getCharacterData(Tok.Tok.getLocation()),
Tok.Tok.getLength());
// For formatting, treat unterminated string literals like normal string
// literals.
if (Tok.is(tok::unknown)) {
if (!Tok.TokenText.empty() && Tok.TokenText[0] == '"') {
Tok.Tok.setKind(tok::string_literal);
Tok.IsUnterminatedLiteral = true;
} else if (Style.Language == FormatStyle::LK_JavaScript &&
Tok.TokenText == "''") {
Tok.Tok.setKind(tok::string_literal);
}
}
if (Style.Language == FormatStyle::LK_JavaScript &&
Tok.is(tok::char_constant)) {
Tok.Tok.setKind(tok::string_literal);
}
if (Tok.is(tok::comment) && (Tok.TokenText == "// clang-format on" ||
Tok.TokenText == "/* clang-format on */")) {
FormattingDisabled = false;
}
Tok.Finalized = FormattingDisabled;
if (Tok.is(tok::comment) && (Tok.TokenText == "// clang-format off" ||
Tok.TokenText == "/* clang-format off */")) {
FormattingDisabled = true;
}
}
void FormatTokenLexer::resetLexer(unsigned Offset) {
StringRef Buffer = SourceMgr.getBufferData(ID);
Lex.reset(new Lexer(SourceMgr.getLocForStartOfFile(ID),
getFormattingLangOpts(Style), Buffer.begin(),
Buffer.begin() + Offset, Buffer.end()));
Lex->SetKeepWhitespaceMode(true);
TrailingWhitespace = 0;
}
} // namespace format
} // namespace clang
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