teak-llvm/clang/lib/Format/WhitespaceManager.cpp
Daniel Jasper 0391e55650 clang-format: Fix access to uninitialized memory.
With incomplete code, we aren't guaranteed to generated changes for
every token. In that case, we need to assume that even the very first
change can continue a preprocessor directive and initialize values
accordingly.

llvm-svn: 231066
2015-03-03 13:59:49 +00:00

357 lines
14 KiB
C++

//===--- WhitespaceManager.cpp - Format C++ code --------------------------===//
//
// 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 WhitespaceManager class.
///
//===----------------------------------------------------------------------===//
#include "WhitespaceManager.h"
#include "llvm/ADT/STLExtras.h"
namespace clang {
namespace format {
bool WhitespaceManager::Change::IsBeforeInFile::
operator()(const Change &C1, const Change &C2) const {
return SourceMgr.isBeforeInTranslationUnit(
C1.OriginalWhitespaceRange.getBegin(),
C2.OriginalWhitespaceRange.getBegin());
}
WhitespaceManager::Change::Change(
bool CreateReplacement, const SourceRange &OriginalWhitespaceRange,
unsigned IndentLevel, int Spaces, unsigned StartOfTokenColumn,
unsigned NewlinesBefore, StringRef PreviousLinePostfix,
StringRef CurrentLinePrefix, tok::TokenKind Kind, bool ContinuesPPDirective)
: CreateReplacement(CreateReplacement),
OriginalWhitespaceRange(OriginalWhitespaceRange),
StartOfTokenColumn(StartOfTokenColumn), NewlinesBefore(NewlinesBefore),
PreviousLinePostfix(PreviousLinePostfix),
CurrentLinePrefix(CurrentLinePrefix), Kind(Kind),
ContinuesPPDirective(ContinuesPPDirective), IndentLevel(IndentLevel),
Spaces(Spaces) {}
void WhitespaceManager::reset() {
Changes.clear();
Replaces.clear();
}
void WhitespaceManager::replaceWhitespace(FormatToken &Tok, unsigned Newlines,
unsigned IndentLevel, unsigned Spaces,
unsigned StartOfTokenColumn,
bool InPPDirective) {
if (Tok.Finalized)
return;
Tok.Decision = (Newlines > 0) ? FD_Break : FD_Continue;
Changes.push_back(Change(true, Tok.WhitespaceRange, IndentLevel, Spaces,
StartOfTokenColumn, Newlines, "", "",
Tok.Tok.getKind(), InPPDirective && !Tok.IsFirst));
}
void WhitespaceManager::addUntouchableToken(const FormatToken &Tok,
bool InPPDirective) {
if (Tok.Finalized)
return;
Changes.push_back(Change(false, Tok.WhitespaceRange, /*IndentLevel=*/0,
/*Spaces=*/0, Tok.OriginalColumn, Tok.NewlinesBefore,
"", "", Tok.Tok.getKind(),
InPPDirective && !Tok.IsFirst));
}
void WhitespaceManager::replaceWhitespaceInToken(
const FormatToken &Tok, unsigned Offset, unsigned ReplaceChars,
StringRef PreviousPostfix, StringRef CurrentPrefix, bool InPPDirective,
unsigned Newlines, unsigned IndentLevel, int Spaces) {
if (Tok.Finalized)
return;
SourceLocation Start = Tok.getStartOfNonWhitespace().getLocWithOffset(Offset);
Changes.push_back(Change(
true, SourceRange(Start, Start.getLocWithOffset(ReplaceChars)),
IndentLevel, Spaces, std::max(0, Spaces), Newlines, PreviousPostfix,
CurrentPrefix,
// If we don't add a newline this change doesn't start a comment. Thus,
// when we align line comments, we don't need to treat this change as one.
// FIXME: We still need to take this change in account to properly
// calculate the new length of the comment and to calculate the changes
// for which to do the alignment when aligning comments.
Tok.is(TT_LineComment) && Newlines > 0 ? tok::comment : tok::unknown,
InPPDirective && !Tok.IsFirst));
}
const tooling::Replacements &WhitespaceManager::generateReplacements() {
if (Changes.empty())
return Replaces;
std::sort(Changes.begin(), Changes.end(), Change::IsBeforeInFile(SourceMgr));
calculateLineBreakInformation();
alignTrailingComments();
alignEscapedNewlines();
generateChanges();
return Replaces;
}
void WhitespaceManager::calculateLineBreakInformation() {
Changes[0].PreviousEndOfTokenColumn = 0;
for (unsigned i = 1, e = Changes.size(); i != e; ++i) {
unsigned OriginalWhitespaceStart =
SourceMgr.getFileOffset(Changes[i].OriginalWhitespaceRange.getBegin());
unsigned PreviousOriginalWhitespaceEnd = SourceMgr.getFileOffset(
Changes[i - 1].OriginalWhitespaceRange.getEnd());
Changes[i - 1].TokenLength = OriginalWhitespaceStart -
PreviousOriginalWhitespaceEnd +
Changes[i].PreviousLinePostfix.size() +
Changes[i - 1].CurrentLinePrefix.size();
Changes[i].PreviousEndOfTokenColumn =
Changes[i - 1].StartOfTokenColumn + Changes[i - 1].TokenLength;
Changes[i - 1].IsTrailingComment =
(Changes[i].NewlinesBefore > 0 || Changes[i].Kind == tok::eof) &&
Changes[i - 1].Kind == tok::comment;
}
// FIXME: The last token is currently not always an eof token; in those
// cases, setting TokenLength of the last token to 0 is wrong.
Changes.back().TokenLength = 0;
Changes.back().IsTrailingComment = Changes.back().Kind == tok::comment;
const WhitespaceManager::Change *LastBlockComment = nullptr;
for (auto &Change : Changes) {
Change.StartOfBlockComment = nullptr;
Change.IndentationOffset = 0;
if (Change.Kind == tok::comment) {
LastBlockComment = &Change;
} else if (Change.Kind == tok::unknown) {
if ((Change.StartOfBlockComment = LastBlockComment))
Change.IndentationOffset =
Change.StartOfTokenColumn -
Change.StartOfBlockComment->StartOfTokenColumn;
} else {
LastBlockComment = nullptr;
}
}
}
void WhitespaceManager::alignTrailingComments() {
unsigned MinColumn = 0;
unsigned MaxColumn = UINT_MAX;
unsigned StartOfSequence = 0;
bool BreakBeforeNext = false;
unsigned Newlines = 0;
for (unsigned i = 0, e = Changes.size(); i != e; ++i) {
if (Changes[i].StartOfBlockComment)
continue;
Newlines += Changes[i].NewlinesBefore;
if (!Changes[i].IsTrailingComment)
continue;
unsigned ChangeMinColumn = Changes[i].StartOfTokenColumn;
unsigned ChangeMaxColumn = Style.ColumnLimit - Changes[i].TokenLength;
if (i + 1 != e && Changes[i + 1].ContinuesPPDirective)
ChangeMaxColumn -= 2;
// If this comment follows an } in column 0, it probably documents the
// closing of a namespace and we don't want to align it.
bool FollowsRBraceInColumn0 = i > 0 && Changes[i].NewlinesBefore == 0 &&
Changes[i - 1].Kind == tok::r_brace &&
Changes[i - 1].StartOfTokenColumn == 0;
bool WasAlignedWithStartOfNextLine = false;
if (Changes[i].NewlinesBefore == 1) { // A comment on its own line.
unsigned CommentColumn = SourceMgr.getSpellingColumnNumber(
Changes[i].OriginalWhitespaceRange.getEnd());
for (unsigned j = i + 1; j != e; ++j) {
if (Changes[j].Kind != tok::comment) { // Skip over comments.
unsigned NextColumn = SourceMgr.getSpellingColumnNumber(
Changes[j].OriginalWhitespaceRange.getEnd());
// The start of the next token was previously aligned with the
// start of this comment.
WasAlignedWithStartOfNextLine =
CommentColumn == NextColumn ||
CommentColumn == NextColumn + Style.IndentWidth;
break;
}
}
}
if (!Style.AlignTrailingComments || FollowsRBraceInColumn0) {
alignTrailingComments(StartOfSequence, i, MinColumn);
MinColumn = ChangeMinColumn;
MaxColumn = ChangeMinColumn;
StartOfSequence = i;
} else if (BreakBeforeNext || Newlines > 1 ||
(ChangeMinColumn > MaxColumn || ChangeMaxColumn < MinColumn) ||
// Break the comment sequence if the previous line did not end
// in a trailing comment.
(Changes[i].NewlinesBefore == 1 && i > 0 &&
!Changes[i - 1].IsTrailingComment) ||
WasAlignedWithStartOfNextLine) {
alignTrailingComments(StartOfSequence, i, MinColumn);
MinColumn = ChangeMinColumn;
MaxColumn = ChangeMaxColumn;
StartOfSequence = i;
} else {
MinColumn = std::max(MinColumn, ChangeMinColumn);
MaxColumn = std::min(MaxColumn, ChangeMaxColumn);
}
BreakBeforeNext =
(i == 0) || (Changes[i].NewlinesBefore > 1) ||
// Never start a sequence with a comment at the beginning of
// the line.
(Changes[i].NewlinesBefore == 1 && StartOfSequence == i);
Newlines = 0;
}
alignTrailingComments(StartOfSequence, Changes.size(), MinColumn);
}
void WhitespaceManager::alignTrailingComments(unsigned Start, unsigned End,
unsigned Column) {
for (unsigned i = Start; i != End; ++i) {
int Shift = 0;
if (Changes[i].IsTrailingComment) {
Shift = Column - Changes[i].StartOfTokenColumn;
}
if (Changes[i].StartOfBlockComment) {
Shift = Changes[i].IndentationOffset +
Changes[i].StartOfBlockComment->StartOfTokenColumn -
Changes[i].StartOfTokenColumn;
}
assert(Shift >= 0);
Changes[i].Spaces += Shift;
if (i + 1 != End)
Changes[i + 1].PreviousEndOfTokenColumn += Shift;
Changes[i].StartOfTokenColumn += Shift;
}
}
void WhitespaceManager::alignEscapedNewlines() {
unsigned MaxEndOfLine =
Style.AlignEscapedNewlinesLeft ? 0 : Style.ColumnLimit;
unsigned StartOfMacro = 0;
Changes[0].EscapedNewlineColumn = 0;
for (unsigned i = 1, e = Changes.size(); i < e; ++i) {
Change &C = Changes[i];
if (C.NewlinesBefore > 0) {
if (C.ContinuesPPDirective) {
MaxEndOfLine = std::max(C.PreviousEndOfTokenColumn + 2, MaxEndOfLine);
} else {
alignEscapedNewlines(StartOfMacro + 1, i, MaxEndOfLine);
MaxEndOfLine = Style.AlignEscapedNewlinesLeft ? 0 : Style.ColumnLimit;
StartOfMacro = i;
}
}
}
alignEscapedNewlines(StartOfMacro + 1, Changes.size(), MaxEndOfLine);
}
void WhitespaceManager::alignEscapedNewlines(unsigned Start, unsigned End,
unsigned Column) {
for (unsigned i = Start; i < End; ++i) {
Change &C = Changes[i];
if (C.NewlinesBefore > 0) {
assert(C.ContinuesPPDirective);
if (C.PreviousEndOfTokenColumn + 1 > Column)
C.EscapedNewlineColumn = 0;
else
C.EscapedNewlineColumn = Column;
}
}
}
void WhitespaceManager::generateChanges() {
for (unsigned i = 0, e = Changes.size(); i != e; ++i) {
const Change &C = Changes[i];
if (i > 0) {
assert(Changes[i - 1].OriginalWhitespaceRange.getBegin() !=
C.OriginalWhitespaceRange.getBegin() &&
"Generating two replacements for the same location");
}
if (C.CreateReplacement) {
std::string ReplacementText = C.PreviousLinePostfix;
if (C.ContinuesPPDirective)
appendNewlineText(ReplacementText, C.NewlinesBefore,
C.PreviousEndOfTokenColumn, C.EscapedNewlineColumn);
else
appendNewlineText(ReplacementText, C.NewlinesBefore);
appendIndentText(ReplacementText, C.IndentLevel, std::max(0, C.Spaces),
C.StartOfTokenColumn - std::max(0, C.Spaces));
ReplacementText.append(C.CurrentLinePrefix);
storeReplacement(C.OriginalWhitespaceRange, ReplacementText);
}
}
}
void WhitespaceManager::storeReplacement(const SourceRange &Range,
StringRef Text) {
unsigned WhitespaceLength = SourceMgr.getFileOffset(Range.getEnd()) -
SourceMgr.getFileOffset(Range.getBegin());
// Don't create a replacement, if it does not change anything.
if (StringRef(SourceMgr.getCharacterData(Range.getBegin()),
WhitespaceLength) == Text)
return;
Replaces.insert(tooling::Replacement(
SourceMgr, CharSourceRange::getCharRange(Range), Text));
}
void WhitespaceManager::appendNewlineText(std::string &Text,
unsigned Newlines) {
for (unsigned i = 0; i < Newlines; ++i)
Text.append(UseCRLF ? "\r\n" : "\n");
}
void WhitespaceManager::appendNewlineText(std::string &Text, unsigned Newlines,
unsigned PreviousEndOfTokenColumn,
unsigned EscapedNewlineColumn) {
if (Newlines > 0) {
unsigned Offset =
std::min<int>(EscapedNewlineColumn - 1, PreviousEndOfTokenColumn);
for (unsigned i = 0; i < Newlines; ++i) {
Text.append(std::string(EscapedNewlineColumn - Offset - 1, ' '));
Text.append(UseCRLF ? "\\\r\n" : "\\\n");
Offset = 0;
}
}
}
void WhitespaceManager::appendIndentText(std::string &Text,
unsigned IndentLevel, unsigned Spaces,
unsigned WhitespaceStartColumn) {
switch (Style.UseTab) {
case FormatStyle::UT_Never:
Text.append(std::string(Spaces, ' '));
break;
case FormatStyle::UT_Always: {
unsigned FirstTabWidth =
Style.TabWidth - WhitespaceStartColumn % Style.TabWidth;
// Indent with tabs only when there's at least one full tab.
if (FirstTabWidth + Style.TabWidth <= Spaces) {
Spaces -= FirstTabWidth;
Text.append("\t");
}
Text.append(std::string(Spaces / Style.TabWidth, '\t'));
Text.append(std::string(Spaces % Style.TabWidth, ' '));
break;
}
case FormatStyle::UT_ForIndentation:
if (WhitespaceStartColumn == 0) {
unsigned Indentation = IndentLevel * Style.IndentWidth;
// This happens, e.g. when a line in a block comment is indented less than
// the first one.
if (Indentation > Spaces)
Indentation = Spaces;
unsigned Tabs = Indentation / Style.TabWidth;
Text.append(std::string(Tabs, '\t'));
Spaces -= Tabs * Style.TabWidth;
}
Text.append(std::string(Spaces, ' '));
break;
}
}
} // namespace format
} // namespace clang