1//===- SourceMgr.cpp - Manager for Simple Source Buffers & Diagnostics ----===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the SourceMgr class. This class is used as a simple
10// substrate for diagnostics, #include handling, and other low level things for
11// simple parsers.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Support/SourceMgr.h"
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/SmallString.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/StringRef.h"
21#include "llvm/ADT/Twine.h"
22#include "llvm/Support/ErrorOr.h"
23#include "llvm/Support/Locale.h"
24#include "llvm/Support/MemoryBuffer.h"
25#include "llvm/Support/Path.h"
26#include "llvm/Support/SMLoc.h"
27#include "llvm/Support/WithColor.h"
28#include "llvm/Support/raw_ostream.h"
29#include <algorithm>
30#include <cassert>
31#include <cstddef>
32#include <limits>
33#include <memory>
34#include <string>
35#include <utility>
36
37using namespace llvm;
38
39static const size_t TabStop = 8;
40
41unsigned SourceMgr::AddIncludeFile(const std::string &Filename,
42 SMLoc IncludeLoc,
43 std::string &IncludedFile) {
44 ErrorOr<std::unique_ptr<MemoryBuffer>> NewBufOrErr =
45 OpenIncludeFile(Filename, IncludedFile);
46 if (!NewBufOrErr)
47 return 0;
48
49 return AddNewSourceBuffer(F: std::move(*NewBufOrErr), IncludeLoc);
50}
51
52ErrorOr<std::unique_ptr<MemoryBuffer>>
53SourceMgr::OpenIncludeFile(const std::string &Filename,
54 std::string &IncludedFile) {
55 ErrorOr<std::unique_ptr<MemoryBuffer>> NewBufOrErr =
56 MemoryBuffer::getFile(Filename);
57
58 SmallString<64> Buffer(Filename);
59 // If the file didn't exist directly, see if it's in an include path.
60 for (unsigned i = 0, e = IncludeDirectories.size(); i != e && !NewBufOrErr;
61 ++i) {
62 Buffer = IncludeDirectories[i];
63 sys::path::append(path&: Buffer, a: Filename);
64 NewBufOrErr = MemoryBuffer::getFile(Filename: Buffer);
65 }
66
67 if (NewBufOrErr)
68 IncludedFile = static_cast<std::string>(Buffer);
69
70 return NewBufOrErr;
71}
72
73unsigned SourceMgr::FindBufferContainingLoc(SMLoc Loc) const {
74 for (unsigned i = 0, e = Buffers.size(); i != e; ++i)
75 if (Loc.getPointer() >= Buffers[i].Buffer->getBufferStart() &&
76 // Use <= here so that a pointer to the null at the end of the buffer
77 // is included as part of the buffer.
78 Loc.getPointer() <= Buffers[i].Buffer->getBufferEnd())
79 return i + 1;
80 return 0;
81}
82
83template <typename T>
84static std::vector<T> &GetOrCreateOffsetCache(void *&OffsetCache,
85 MemoryBuffer *Buffer) {
86 if (OffsetCache)
87 return *static_cast<std::vector<T> *>(OffsetCache);
88
89 // Lazily fill in the offset cache.
90 auto *Offsets = new std::vector<T>();
91 size_t Sz = Buffer->getBufferSize();
92 assert(Sz <= std::numeric_limits<T>::max());
93 StringRef S = Buffer->getBuffer();
94 for (size_t N = 0; N < Sz; ++N) {
95 if (S[N] == '\n')
96 Offsets->push_back(static_cast<T>(N));
97 }
98
99 OffsetCache = Offsets;
100 return *Offsets;
101}
102
103template <typename T>
104unsigned SourceMgr::SrcBuffer::getLineNumberSpecialized(const char *Ptr) const {
105 std::vector<T> &Offsets =
106 GetOrCreateOffsetCache<T>(OffsetCache, Buffer.get());
107
108 const char *BufStart = Buffer->getBufferStart();
109 assert(Ptr >= BufStart && Ptr <= Buffer->getBufferEnd());
110 ptrdiff_t PtrDiff = Ptr - BufStart;
111 assert(PtrDiff >= 0 &&
112 static_cast<size_t>(PtrDiff) <= std::numeric_limits<T>::max());
113 T PtrOffset = static_cast<T>(PtrDiff);
114
115 // llvm::lower_bound gives the number of EOL before PtrOffset. Add 1 to get
116 // the line number.
117 return llvm::lower_bound(Offsets, PtrOffset) - Offsets.begin() + 1;
118}
119
120/// Look up a given \p Ptr in the buffer, determining which line it came
121/// from.
122unsigned SourceMgr::SrcBuffer::getLineNumber(const char *Ptr) const {
123 size_t Sz = Buffer->getBufferSize();
124 if (Sz <= std::numeric_limits<uint8_t>::max())
125 return getLineNumberSpecialized<uint8_t>(Ptr);
126 else if (Sz <= std::numeric_limits<uint16_t>::max())
127 return getLineNumberSpecialized<uint16_t>(Ptr);
128 else if (Sz <= std::numeric_limits<uint32_t>::max())
129 return getLineNumberSpecialized<uint32_t>(Ptr);
130 else
131 return getLineNumberSpecialized<uint64_t>(Ptr);
132}
133
134template <typename T>
135const char *SourceMgr::SrcBuffer::getPointerForLineNumberSpecialized(
136 unsigned LineNo) const {
137 std::vector<T> &Offsets =
138 GetOrCreateOffsetCache<T>(OffsetCache, Buffer.get());
139
140 // We start counting line and column numbers from 1.
141 if (LineNo != 0)
142 --LineNo;
143
144 const char *BufStart = Buffer->getBufferStart();
145
146 // The offset cache contains the location of the \n for the specified line,
147 // we want the start of the line. As such, we look for the previous entry.
148 if (LineNo == 0)
149 return BufStart;
150 if (LineNo > Offsets.size())
151 return nullptr;
152 return BufStart + Offsets[LineNo - 1] + 1;
153}
154
155/// Return a pointer to the first character of the specified line number or
156/// null if the line number is invalid.
157const char *
158SourceMgr::SrcBuffer::getPointerForLineNumber(unsigned LineNo) const {
159 size_t Sz = Buffer->getBufferSize();
160 if (Sz <= std::numeric_limits<uint8_t>::max())
161 return getPointerForLineNumberSpecialized<uint8_t>(LineNo);
162 else if (Sz <= std::numeric_limits<uint16_t>::max())
163 return getPointerForLineNumberSpecialized<uint16_t>(LineNo);
164 else if (Sz <= std::numeric_limits<uint32_t>::max())
165 return getPointerForLineNumberSpecialized<uint32_t>(LineNo);
166 else
167 return getPointerForLineNumberSpecialized<uint64_t>(LineNo);
168}
169
170SourceMgr::SrcBuffer::SrcBuffer(SourceMgr::SrcBuffer &&Other)
171 : Buffer(std::move(Other.Buffer)), OffsetCache(Other.OffsetCache),
172 IncludeLoc(Other.IncludeLoc) {
173 Other.OffsetCache = nullptr;
174}
175
176SourceMgr::SrcBuffer::~SrcBuffer() {
177 if (OffsetCache) {
178 size_t Sz = Buffer->getBufferSize();
179 if (Sz <= std::numeric_limits<uint8_t>::max())
180 delete static_cast<std::vector<uint8_t> *>(OffsetCache);
181 else if (Sz <= std::numeric_limits<uint16_t>::max())
182 delete static_cast<std::vector<uint16_t> *>(OffsetCache);
183 else if (Sz <= std::numeric_limits<uint32_t>::max())
184 delete static_cast<std::vector<uint32_t> *>(OffsetCache);
185 else
186 delete static_cast<std::vector<uint64_t> *>(OffsetCache);
187 OffsetCache = nullptr;
188 }
189}
190
191std::pair<unsigned, unsigned>
192SourceMgr::getLineAndColumn(SMLoc Loc, unsigned BufferID) const {
193 if (!BufferID)
194 BufferID = FindBufferContainingLoc(Loc);
195 assert(BufferID && "Invalid location!");
196
197 auto &SB = getBufferInfo(i: BufferID);
198 const char *Ptr = Loc.getPointer();
199
200 unsigned LineNo = SB.getLineNumber(Ptr);
201 const char *BufStart = SB.Buffer->getBufferStart();
202 size_t NewlineOffs = StringRef(BufStart, Ptr - BufStart).find_last_of(Chars: "\n\r");
203 if (NewlineOffs == StringRef::npos)
204 NewlineOffs = ~(size_t)0;
205 return std::make_pair(x&: LineNo, y: Ptr - BufStart - NewlineOffs);
206}
207
208// FIXME: Note that the formatting of source locations is spread between
209// multiple functions, some in SourceMgr and some in SMDiagnostic. A better
210// solution would be a general-purpose source location formatter
211// in one of those two classes, or possibly in SMLoc.
212
213/// Get a string with the source location formatted in the standard
214/// style, but without the line offset. If \p IncludePath is true, the path
215/// is included. If false, only the file name and extension are included.
216std::string SourceMgr::getFormattedLocationNoOffset(SMLoc Loc,
217 bool IncludePath) const {
218 auto BufferID = FindBufferContainingLoc(Loc);
219 assert(BufferID && "Invalid location!");
220 auto FileSpec = getBufferInfo(i: BufferID).Buffer->getBufferIdentifier();
221
222 if (IncludePath) {
223 return FileSpec.str() + ":" + std::to_string(val: FindLineNumber(Loc, BufferID));
224 } else {
225 auto I = FileSpec.find_last_of(Chars: "/\\");
226 I = (I == FileSpec.size()) ? 0 : (I + 1);
227 return FileSpec.substr(Start: I).str() + ":" +
228 std::to_string(val: FindLineNumber(Loc, BufferID));
229 }
230}
231
232/// Given a line and column number in a mapped buffer, turn it into an SMLoc.
233/// This will return a null SMLoc if the line/column location is invalid.
234SMLoc SourceMgr::FindLocForLineAndColumn(unsigned BufferID, unsigned LineNo,
235 unsigned ColNo) {
236 auto &SB = getBufferInfo(i: BufferID);
237 const char *Ptr = SB.getPointerForLineNumber(LineNo);
238 if (!Ptr)
239 return SMLoc();
240
241 // We start counting line and column numbers from 1.
242 if (ColNo != 0)
243 --ColNo;
244
245 // If we have a column number, validate it.
246 if (ColNo) {
247 // Make sure the location is within the current line.
248 if (Ptr + ColNo > SB.Buffer->getBufferEnd())
249 return SMLoc();
250
251 // Make sure there is no newline in the way.
252 if (StringRef(Ptr, ColNo).find_first_of(Chars: "\n\r") != StringRef::npos)
253 return SMLoc();
254
255 Ptr += ColNo;
256 }
257
258 return SMLoc::getFromPointer(Ptr);
259}
260
261void SourceMgr::PrintIncludeStack(SMLoc IncludeLoc, raw_ostream &OS) const {
262 if (IncludeLoc == SMLoc())
263 return; // Top of stack.
264
265 unsigned CurBuf = FindBufferContainingLoc(Loc: IncludeLoc);
266 assert(CurBuf && "Invalid or unspecified location!");
267
268 PrintIncludeStack(IncludeLoc: getBufferInfo(i: CurBuf).IncludeLoc, OS);
269
270 OS << "Included from " << getBufferInfo(i: CurBuf).Buffer->getBufferIdentifier()
271 << ":" << FindLineNumber(Loc: IncludeLoc, BufferID: CurBuf) << ":\n";
272}
273
274SMDiagnostic SourceMgr::GetMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
275 const Twine &Msg, ArrayRef<SMRange> Ranges,
276 ArrayRef<SMFixIt> FixIts) const {
277 // First thing to do: find the current buffer containing the specified
278 // location to pull out the source line.
279 SmallVector<std::pair<unsigned, unsigned>, 4> ColRanges;
280 std::pair<unsigned, unsigned> LineAndCol;
281 StringRef BufferID = "<unknown>";
282 StringRef LineStr;
283
284 if (Loc.isValid()) {
285 unsigned CurBuf = FindBufferContainingLoc(Loc);
286 assert(CurBuf && "Invalid or unspecified location!");
287
288 const MemoryBuffer *CurMB = getMemoryBuffer(i: CurBuf);
289 BufferID = CurMB->getBufferIdentifier();
290
291 // Scan backward to find the start of the line.
292 const char *LineStart = Loc.getPointer();
293 const char *BufStart = CurMB->getBufferStart();
294 while (LineStart != BufStart && LineStart[-1] != '\n' &&
295 LineStart[-1] != '\r')
296 --LineStart;
297
298 // Get the end of the line.
299 const char *LineEnd = Loc.getPointer();
300 const char *BufEnd = CurMB->getBufferEnd();
301 while (LineEnd != BufEnd && LineEnd[0] != '\n' && LineEnd[0] != '\r')
302 ++LineEnd;
303 LineStr = StringRef(LineStart, LineEnd - LineStart);
304
305 // Convert any ranges to column ranges that only intersect the line of the
306 // location.
307 for (SMRange R : Ranges) {
308 if (!R.isValid())
309 continue;
310
311 // If the line doesn't contain any part of the range, then ignore it.
312 if (R.Start.getPointer() > LineEnd || R.End.getPointer() < LineStart)
313 continue;
314
315 // Ignore pieces of the range that go onto other lines.
316 if (R.Start.getPointer() < LineStart)
317 R.Start = SMLoc::getFromPointer(Ptr: LineStart);
318 if (R.End.getPointer() > LineEnd)
319 R.End = SMLoc::getFromPointer(Ptr: LineEnd);
320
321 // Translate from SMLoc ranges to column ranges.
322 // FIXME: Handle multibyte characters.
323 ColRanges.push_back(Elt: std::make_pair(x: R.Start.getPointer() - LineStart,
324 y: R.End.getPointer() - LineStart));
325 }
326
327 LineAndCol = getLineAndColumn(Loc, BufferID: CurBuf);
328 }
329
330 return SMDiagnostic(*this, Loc, BufferID, LineAndCol.first,
331 LineAndCol.second - 1, Kind, Msg.str(), LineStr,
332 ColRanges, FixIts);
333}
334
335void SourceMgr::PrintMessage(raw_ostream &OS, const SMDiagnostic &Diagnostic,
336 bool ShowColors) const {
337 // Report the message with the diagnostic handler if present.
338 if (DiagHandler) {
339 DiagHandler(Diagnostic, DiagContext);
340 return;
341 }
342
343 if (Diagnostic.getLoc().isValid()) {
344 unsigned CurBuf = FindBufferContainingLoc(Loc: Diagnostic.getLoc());
345 assert(CurBuf && "Invalid or unspecified location!");
346 PrintIncludeStack(IncludeLoc: getBufferInfo(i: CurBuf).IncludeLoc, OS);
347 }
348
349 Diagnostic.print(ProgName: nullptr, S&: OS, ShowColors);
350}
351
352void SourceMgr::PrintMessage(raw_ostream &OS, SMLoc Loc,
353 SourceMgr::DiagKind Kind, const Twine &Msg,
354 ArrayRef<SMRange> Ranges, ArrayRef<SMFixIt> FixIts,
355 bool ShowColors) const {
356 PrintMessage(OS, Diagnostic: GetMessage(Loc, Kind, Msg, Ranges, FixIts), ShowColors);
357}
358
359void SourceMgr::PrintMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
360 const Twine &Msg, ArrayRef<SMRange> Ranges,
361 ArrayRef<SMFixIt> FixIts, bool ShowColors) const {
362 PrintMessage(OS&: errs(), Loc, Kind, Msg, Ranges, FixIts, ShowColors);
363}
364
365//===----------------------------------------------------------------------===//
366// SMFixIt Implementation
367//===----------------------------------------------------------------------===//
368
369SMFixIt::SMFixIt(SMRange R, const Twine &Replacement)
370 : Range(R), Text(Replacement.str()) {
371 assert(R.isValid());
372}
373
374//===----------------------------------------------------------------------===//
375// SMDiagnostic Implementation
376//===----------------------------------------------------------------------===//
377
378SMDiagnostic::SMDiagnostic(const SourceMgr &sm, SMLoc L, StringRef FN, int Line,
379 int Col, SourceMgr::DiagKind Kind, StringRef Msg,
380 StringRef LineStr,
381 ArrayRef<std::pair<unsigned, unsigned>> Ranges,
382 ArrayRef<SMFixIt> Hints)
383 : SM(&sm), Loc(L), Filename(std::string(FN)), LineNo(Line), ColumnNo(Col),
384 Kind(Kind), Message(Msg), LineContents(LineStr), Ranges(Ranges.vec()),
385 FixIts(Hints.begin(), Hints.end()) {
386 llvm::sort(C&: FixIts);
387}
388
389static void buildFixItLine(std::string &CaretLine, std::string &FixItLine,
390 ArrayRef<SMFixIt> FixIts,
391 ArrayRef<char> SourceLine) {
392 if (FixIts.empty())
393 return;
394
395 const char *LineStart = SourceLine.begin();
396 const char *LineEnd = SourceLine.end();
397
398 size_t PrevHintEndCol = 0;
399
400 for (const llvm::SMFixIt &Fixit : FixIts) {
401 // If the fixit contains a newline or tab, ignore it.
402 if (Fixit.getText().find_first_of(Chars: "\n\r\t") != StringRef::npos)
403 continue;
404
405 SMRange R = Fixit.getRange();
406
407 // If the line doesn't contain any part of the range, then ignore it.
408 if (R.Start.getPointer() > LineEnd || R.End.getPointer() < LineStart)
409 continue;
410
411 // Translate from SMLoc to column.
412 // Ignore pieces of the range that go onto other lines.
413 // FIXME: Handle multibyte characters in the source line.
414 unsigned FirstCol;
415 if (R.Start.getPointer() < LineStart)
416 FirstCol = 0;
417 else
418 FirstCol = R.Start.getPointer() - LineStart;
419
420 // If we inserted a long previous hint, push this one forwards, and add
421 // an extra space to show that this is not part of the previous
422 // completion. This is sort of the best we can do when two hints appear
423 // to overlap.
424 //
425 // Note that if this hint is located immediately after the previous
426 // hint, no space will be added, since the location is more important.
427 unsigned HintCol = FirstCol;
428 if (HintCol < PrevHintEndCol)
429 HintCol = PrevHintEndCol + 1;
430
431 // FIXME: This assertion is intended to catch unintended use of multibyte
432 // characters in fixits. If we decide to do this, we'll have to track
433 // separate byte widths for the source and fixit lines.
434 assert((size_t)sys::locale::columnWidth(Fixit.getText()) ==
435 Fixit.getText().size());
436
437 // This relies on one byte per column in our fixit hints.
438 unsigned LastColumnModified = HintCol + Fixit.getText().size();
439 if (LastColumnModified > FixItLine.size())
440 FixItLine.resize(n: LastColumnModified, c: ' ');
441
442 llvm::copy(Range: Fixit.getText(), Out: FixItLine.begin() + HintCol);
443
444 PrevHintEndCol = LastColumnModified;
445
446 // For replacements, mark the removal range with '~'.
447 // FIXME: Handle multibyte characters in the source line.
448 unsigned LastCol;
449 if (R.End.getPointer() >= LineEnd)
450 LastCol = LineEnd - LineStart;
451 else
452 LastCol = R.End.getPointer() - LineStart;
453
454 std::fill(first: &CaretLine[FirstCol], last: &CaretLine[LastCol], value: '~');
455 }
456}
457
458static void printSourceLine(raw_ostream &S, StringRef LineContents) {
459 // Print out the source line one character at a time, so we can expand tabs.
460 for (unsigned i = 0, e = LineContents.size(), OutCol = 0; i != e; ++i) {
461 size_t NextTab = LineContents.find(C: '\t', From: i);
462 // If there were no tabs left, print the rest, we are done.
463 if (NextTab == StringRef::npos) {
464 S << LineContents.drop_front(N: i);
465 break;
466 }
467
468 // Otherwise, print from i to NextTab.
469 S << LineContents.slice(Start: i, End: NextTab);
470 OutCol += NextTab - i;
471 i = NextTab;
472
473 // If we have a tab, emit at least one space, then round up to 8 columns.
474 do {
475 S << ' ';
476 ++OutCol;
477 } while ((OutCol % TabStop) != 0);
478 }
479 S << '\n';
480}
481
482static bool isNonASCII(char c) { return c & 0x80; }
483
484void SMDiagnostic::print(const char *ProgName, raw_ostream &OS, bool ShowColors,
485 bool ShowKindLabel) const {
486 ColorMode Mode = ShowColors ? ColorMode::Auto : ColorMode::Disable;
487
488 {
489 WithColor S(OS, raw_ostream::SAVEDCOLOR, true, false, Mode);
490
491 if (ProgName && ProgName[0])
492 S << ProgName << ": ";
493
494 if (!Filename.empty()) {
495 if (Filename == "-")
496 S << "<stdin>";
497 else
498 S << Filename;
499
500 if (LineNo != -1) {
501 S << ':' << LineNo;
502 if (ColumnNo != -1)
503 S << ':' << (ColumnNo + 1);
504 }
505 S << ": ";
506 }
507 }
508
509 if (ShowKindLabel) {
510 switch (Kind) {
511 case SourceMgr::DK_Error:
512 WithColor::error(OS, Prefix: "", DisableColors: !ShowColors);
513 break;
514 case SourceMgr::DK_Warning:
515 WithColor::warning(OS, Prefix: "", DisableColors: !ShowColors);
516 break;
517 case SourceMgr::DK_Note:
518 WithColor::note(OS, Prefix: "", DisableColors: !ShowColors);
519 break;
520 case SourceMgr::DK_Remark:
521 WithColor::remark(OS, Prefix: "", DisableColors: !ShowColors);
522 break;
523 }
524 }
525
526 WithColor(OS, raw_ostream::SAVEDCOLOR, true, false, Mode) << Message << '\n';
527
528 if (LineNo == -1 || ColumnNo == -1)
529 return;
530
531 // FIXME: If there are multibyte or multi-column characters in the source, all
532 // our ranges will be wrong. To do this properly, we'll need a byte-to-column
533 // map like Clang's TextDiagnostic. For now, we'll just handle tabs by
534 // expanding them later, and bail out rather than show incorrect ranges and
535 // misaligned fixits for any other odd characters.
536 if (any_of(Range: LineContents, P: isNonASCII)) {
537 printSourceLine(S&: OS, LineContents);
538 return;
539 }
540 size_t NumColumns = LineContents.size();
541
542 // Build the line with the caret and ranges.
543 std::string CaretLine(NumColumns + 1, ' ');
544
545 // Expand any ranges.
546 for (const std::pair<unsigned, unsigned> &R : Ranges)
547 std::fill(first: &CaretLine[R.first],
548 last: &CaretLine[std::min(a: (size_t)R.second, b: CaretLine.size())], value: '~');
549
550 // Add any fix-its.
551 // FIXME: Find the beginning of the line properly for multibyte characters.
552 std::string FixItInsertionLine;
553 buildFixItLine(CaretLine, FixItLine&: FixItInsertionLine, FixIts,
554 SourceLine: ArrayRef(Loc.getPointer() - ColumnNo, LineContents.size()));
555
556 // Finally, plop on the caret.
557 if (unsigned(ColumnNo) <= NumColumns)
558 CaretLine[ColumnNo] = '^';
559 else
560 CaretLine[NumColumns] = '^';
561
562 // ... and remove trailing whitespace so the output doesn't wrap for it. We
563 // know that the line isn't completely empty because it has the caret in it at
564 // least.
565 CaretLine.erase(pos: CaretLine.find_last_not_of(c: ' ') + 1);
566
567 printSourceLine(S&: OS, LineContents);
568
569 {
570 ColorMode Mode = ShowColors ? ColorMode::Auto : ColorMode::Disable;
571 WithColor S(OS, raw_ostream::GREEN, true, false, Mode);
572
573 // Print out the caret line, matching tabs in the source line.
574 for (unsigned i = 0, e = CaretLine.size(), OutCol = 0; i != e; ++i) {
575 if (i >= LineContents.size() || LineContents[i] != '\t') {
576 S << CaretLine[i];
577 ++OutCol;
578 continue;
579 }
580
581 // Okay, we have a tab. Insert the appropriate number of characters.
582 do {
583 S << CaretLine[i];
584 ++OutCol;
585 } while ((OutCol % TabStop) != 0);
586 }
587 S << '\n';
588 }
589
590 // Print out the replacement line, matching tabs in the source line.
591 if (FixItInsertionLine.empty())
592 return;
593
594 for (size_t i = 0, e = FixItInsertionLine.size(), OutCol = 0; i < e; ++i) {
595 if (i >= LineContents.size() || LineContents[i] != '\t') {
596 OS << FixItInsertionLine[i];
597 ++OutCol;
598 continue;
599 }
600
601 // Okay, we have a tab. Insert the appropriate number of characters.
602 do {
603 OS << FixItInsertionLine[i];
604 // FIXME: This is trying not to break up replacements, but then to re-sync
605 // with the tabs between replacements. This will fail, though, if two
606 // fix-it replacements are exactly adjacent, or if a fix-it contains a
607 // space. Really we should be precomputing column widths, which we'll
608 // need anyway for multibyte chars.
609 if (FixItInsertionLine[i] != ' ')
610 ++i;
611 ++OutCol;
612 } while (((OutCol % TabStop) != 0) && i != e);
613 }
614 OS << '\n';
615}
616

source code of llvm/lib/Support/SourceMgr.cpp