1 //===--- raw_ostream.cpp - Implement the raw_ostream classes --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This implements support for bulk buffered stream output.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/Support/raw_ostream.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/Config/config.h"
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/Format.h"
22 #include "llvm/Support/Process.h"
23 #include "llvm/Support/Program.h"
24 #include "llvm/Support/system_error.h"
25 #include <cctype>
26 #include <cerrno>
27 #include <sys/stat.h>
28 #include <sys/types.h>
29
30 #if defined(HAVE_UNISTD_H)
31 # include <unistd.h>
32 #endif
33 #if defined(HAVE_FCNTL_H)
34 # include <fcntl.h>
35 #endif
36 #if defined(HAVE_SYS_UIO_H) && defined(HAVE_WRITEV)
37 # include <sys/uio.h>
38 #endif
39
40 #if defined(__CYGWIN__)
41 #include <io.h>
42 #endif
43
44 #if defined(_MSC_VER)
45 #include <io.h>
46 #include <fcntl.h>
47 #ifndef STDIN_FILENO
48 # define STDIN_FILENO 0
49 #endif
50 #ifndef STDOUT_FILENO
51 # define STDOUT_FILENO 1
52 #endif
53 #ifndef STDERR_FILENO
54 # define STDERR_FILENO 2
55 #endif
56 #endif
57
58 using namespace llvm;
59
~raw_ostream()60 raw_ostream::~raw_ostream() {
61 // raw_ostream's subclasses should take care to flush the buffer
62 // in their destructors.
63 assert(OutBufCur == OutBufStart &&
64 "raw_ostream destructor called with non-empty buffer!");
65
66 if (BufferMode == InternalBuffer)
67 delete [] OutBufStart;
68 }
69
70 // An out of line virtual method to provide a home for the class vtable.
handle()71 void raw_ostream::handle() {}
72
preferred_buffer_size() const73 size_t raw_ostream::preferred_buffer_size() const {
74 // BUFSIZ is intended to be a reasonable default.
75 return BUFSIZ;
76 }
77
SetBuffered()78 void raw_ostream::SetBuffered() {
79 // Ask the subclass to determine an appropriate buffer size.
80 if (size_t Size = preferred_buffer_size())
81 SetBufferSize(Size);
82 else
83 // It may return 0, meaning this stream should be unbuffered.
84 SetUnbuffered();
85 }
86
SetBufferAndMode(char * BufferStart,size_t Size,BufferKind Mode)87 void raw_ostream::SetBufferAndMode(char *BufferStart, size_t Size,
88 BufferKind Mode) {
89 assert(((Mode == Unbuffered && BufferStart == 0 && Size == 0) ||
90 (Mode != Unbuffered && BufferStart && Size)) &&
91 "stream must be unbuffered or have at least one byte");
92 // Make sure the current buffer is free of content (we can't flush here; the
93 // child buffer management logic will be in write_impl).
94 assert(GetNumBytesInBuffer() == 0 && "Current buffer is non-empty!");
95
96 if (BufferMode == InternalBuffer)
97 delete [] OutBufStart;
98 OutBufStart = BufferStart;
99 OutBufEnd = OutBufStart+Size;
100 OutBufCur = OutBufStart;
101 BufferMode = Mode;
102
103 assert(OutBufStart <= OutBufEnd && "Invalid size!");
104 }
105
operator <<(unsigned long N)106 raw_ostream &raw_ostream::operator<<(unsigned long N) {
107 // Zero is a special case.
108 if (N == 0)
109 return *this << '0';
110
111 char NumberBuffer[20];
112 char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
113 char *CurPtr = EndPtr;
114
115 while (N) {
116 *--CurPtr = '0' + char(N % 10);
117 N /= 10;
118 }
119 return write(CurPtr, EndPtr-CurPtr);
120 }
121
operator <<(long N)122 raw_ostream &raw_ostream::operator<<(long N) {
123 if (N < 0) {
124 *this << '-';
125 // Avoid undefined behavior on LONG_MIN with a cast.
126 N = -(unsigned long)N;
127 }
128
129 return this->operator<<(static_cast<unsigned long>(N));
130 }
131
operator <<(unsigned long long N)132 raw_ostream &raw_ostream::operator<<(unsigned long long N) {
133 // Output using 32-bit div/mod when possible.
134 if (N == static_cast<unsigned long>(N))
135 return this->operator<<(static_cast<unsigned long>(N));
136
137 char NumberBuffer[20];
138 char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
139 char *CurPtr = EndPtr;
140
141 while (N) {
142 *--CurPtr = '0' + char(N % 10);
143 N /= 10;
144 }
145 return write(CurPtr, EndPtr-CurPtr);
146 }
147
operator <<(long long N)148 raw_ostream &raw_ostream::operator<<(long long N) {
149 if (N < 0) {
150 *this << '-';
151 // Avoid undefined behavior on INT64_MIN with a cast.
152 N = -(unsigned long long)N;
153 }
154
155 return this->operator<<(static_cast<unsigned long long>(N));
156 }
157
write_hex(unsigned long long N)158 raw_ostream &raw_ostream::write_hex(unsigned long long N) {
159 // Zero is a special case.
160 if (N == 0)
161 return *this << '0';
162
163 char NumberBuffer[20];
164 char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
165 char *CurPtr = EndPtr;
166
167 while (N) {
168 uintptr_t x = N % 16;
169 *--CurPtr = (x < 10 ? '0' + x : 'a' + x - 10);
170 N /= 16;
171 }
172
173 return write(CurPtr, EndPtr-CurPtr);
174 }
175
write_escaped(StringRef Str,bool UseHexEscapes)176 raw_ostream &raw_ostream::write_escaped(StringRef Str,
177 bool UseHexEscapes) {
178 for (unsigned i = 0, e = Str.size(); i != e; ++i) {
179 unsigned char c = Str[i];
180
181 switch (c) {
182 case '\\':
183 *this << '\\' << '\\';
184 break;
185 case '\t':
186 *this << '\\' << 't';
187 break;
188 case '\n':
189 *this << '\\' << 'n';
190 break;
191 case '"':
192 *this << '\\' << '"';
193 break;
194 default:
195 if (std::isprint(c)) {
196 *this << c;
197 break;
198 }
199
200 // Write out the escaped representation.
201 if (UseHexEscapes) {
202 *this << '\\' << 'x';
203 *this << hexdigit((c >> 4 & 0xF));
204 *this << hexdigit((c >> 0) & 0xF);
205 } else {
206 // Always use a full 3-character octal escape.
207 *this << '\\';
208 *this << char('0' + ((c >> 6) & 7));
209 *this << char('0' + ((c >> 3) & 7));
210 *this << char('0' + ((c >> 0) & 7));
211 }
212 }
213 }
214
215 return *this;
216 }
217
operator <<(const void * P)218 raw_ostream &raw_ostream::operator<<(const void *P) {
219 *this << '0' << 'x';
220
221 return write_hex((uintptr_t) P);
222 }
223
operator <<(double N)224 raw_ostream &raw_ostream::operator<<(double N) {
225 #ifdef _WIN32
226 // On MSVCRT and compatible, output of %e is incompatible to Posix
227 // by default. Number of exponent digits should be at least 2. "%+03d"
228 // FIXME: Implement our formatter to here or Support/Format.h!
229 int fpcl = _fpclass(N);
230
231 // negative zero
232 if (fpcl == _FPCLASS_NZ)
233 return *this << "-0.000000e+00";
234
235 char buf[16];
236 unsigned len;
237 len = snprintf(buf, sizeof(buf), "%e", N);
238 if (len <= sizeof(buf) - 2) {
239 if (len >= 5 && buf[len - 5] == 'e' && buf[len - 3] == '0') {
240 int cs = buf[len - 4];
241 if (cs == '+' || cs == '-') {
242 int c1 = buf[len - 2];
243 int c0 = buf[len - 1];
244 if (isdigit(static_cast<unsigned char>(c1)) &&
245 isdigit(static_cast<unsigned char>(c0))) {
246 // Trim leading '0': "...e+012" -> "...e+12\0"
247 buf[len - 3] = c1;
248 buf[len - 2] = c0;
249 buf[--len] = 0;
250 }
251 }
252 }
253 return this->operator<<(buf);
254 }
255 #endif
256 return this->operator<<(format("%e", N));
257 }
258
259
260
flush_nonempty()261 void raw_ostream::flush_nonempty() {
262 assert(OutBufCur > OutBufStart && "Invalid call to flush_nonempty.");
263 size_t Length = OutBufCur - OutBufStart;
264 OutBufCur = OutBufStart;
265 write_impl(OutBufStart, Length);
266 }
267
write(unsigned char C)268 raw_ostream &raw_ostream::write(unsigned char C) {
269 // Group exceptional cases into a single branch.
270 if (LLVM_UNLIKELY(OutBufCur >= OutBufEnd)) {
271 if (LLVM_UNLIKELY(!OutBufStart)) {
272 if (BufferMode == Unbuffered) {
273 write_impl(reinterpret_cast<char*>(&C), 1);
274 return *this;
275 }
276 // Set up a buffer and start over.
277 SetBuffered();
278 return write(C);
279 }
280
281 flush_nonempty();
282 }
283
284 *OutBufCur++ = C;
285 return *this;
286 }
287
write(const char * Ptr,size_t Size)288 raw_ostream &raw_ostream::write(const char *Ptr, size_t Size) {
289 // Group exceptional cases into a single branch.
290 if (LLVM_UNLIKELY(size_t(OutBufEnd - OutBufCur) < Size)) {
291 if (LLVM_UNLIKELY(!OutBufStart)) {
292 if (BufferMode == Unbuffered) {
293 write_impl(Ptr, Size);
294 return *this;
295 }
296 // Set up a buffer and start over.
297 SetBuffered();
298 return write(Ptr, Size);
299 }
300
301 size_t NumBytes = OutBufEnd - OutBufCur;
302
303 // If the buffer is empty at this point we have a string that is larger
304 // than the buffer. Directly write the chunk that is a multiple of the
305 // preferred buffer size and put the remainder in the buffer.
306 if (LLVM_UNLIKELY(OutBufCur == OutBufStart)) {
307 size_t BytesToWrite = Size - (Size % NumBytes);
308 write_impl(Ptr, BytesToWrite);
309 size_t BytesRemaining = Size - BytesToWrite;
310 if (BytesRemaining > size_t(OutBufEnd - OutBufCur)) {
311 // Too much left over to copy into our buffer.
312 return write(Ptr + BytesToWrite, BytesRemaining);
313 }
314 copy_to_buffer(Ptr + BytesToWrite, BytesRemaining);
315 return *this;
316 }
317
318 // We don't have enough space in the buffer to fit the string in. Insert as
319 // much as possible, flush and start over with the remainder.
320 copy_to_buffer(Ptr, NumBytes);
321 flush_nonempty();
322 return write(Ptr + NumBytes, Size - NumBytes);
323 }
324
325 copy_to_buffer(Ptr, Size);
326
327 return *this;
328 }
329
copy_to_buffer(const char * Ptr,size_t Size)330 void raw_ostream::copy_to_buffer(const char *Ptr, size_t Size) {
331 assert(Size <= size_t(OutBufEnd - OutBufCur) && "Buffer overrun!");
332
333 // Handle short strings specially, memcpy isn't very good at very short
334 // strings.
335 switch (Size) {
336 case 4: OutBufCur[3] = Ptr[3]; // FALL THROUGH
337 case 3: OutBufCur[2] = Ptr[2]; // FALL THROUGH
338 case 2: OutBufCur[1] = Ptr[1]; // FALL THROUGH
339 case 1: OutBufCur[0] = Ptr[0]; // FALL THROUGH
340 case 0: break;
341 default:
342 memcpy(OutBufCur, Ptr, Size);
343 break;
344 }
345
346 OutBufCur += Size;
347 }
348
349 // Formatted output.
operator <<(const format_object_base & Fmt)350 raw_ostream &raw_ostream::operator<<(const format_object_base &Fmt) {
351 // If we have more than a few bytes left in our output buffer, try
352 // formatting directly onto its end.
353 size_t NextBufferSize = 127;
354 size_t BufferBytesLeft = OutBufEnd - OutBufCur;
355 if (BufferBytesLeft > 3) {
356 size_t BytesUsed = Fmt.print(OutBufCur, BufferBytesLeft);
357
358 // Common case is that we have plenty of space.
359 if (BytesUsed <= BufferBytesLeft) {
360 OutBufCur += BytesUsed;
361 return *this;
362 }
363
364 // Otherwise, we overflowed and the return value tells us the size to try
365 // again with.
366 NextBufferSize = BytesUsed;
367 }
368
369 // If we got here, we didn't have enough space in the output buffer for the
370 // string. Try printing into a SmallVector that is resized to have enough
371 // space. Iterate until we win.
372 SmallVector<char, 128> V;
373
374 while (1) {
375 V.resize(NextBufferSize);
376
377 // Try formatting into the SmallVector.
378 size_t BytesUsed = Fmt.print(V.data(), NextBufferSize);
379
380 // If BytesUsed fit into the vector, we win.
381 if (BytesUsed <= NextBufferSize)
382 return write(V.data(), BytesUsed);
383
384 // Otherwise, try again with a new size.
385 assert(BytesUsed > NextBufferSize && "Didn't grow buffer!?");
386 NextBufferSize = BytesUsed;
387 }
388 }
389
390 /// indent - Insert 'NumSpaces' spaces.
indent(unsigned NumSpaces)391 raw_ostream &raw_ostream::indent(unsigned NumSpaces) {
392 static const char Spaces[] = " "
393 " "
394 " ";
395
396 // Usually the indentation is small, handle it with a fastpath.
397 if (NumSpaces < array_lengthof(Spaces))
398 return write(Spaces, NumSpaces);
399
400 while (NumSpaces) {
401 unsigned NumToWrite = std::min(NumSpaces,
402 (unsigned)array_lengthof(Spaces)-1);
403 write(Spaces, NumToWrite);
404 NumSpaces -= NumToWrite;
405 }
406 return *this;
407 }
408
409
410 //===----------------------------------------------------------------------===//
411 // Formatted Output
412 //===----------------------------------------------------------------------===//
413
414 // Out of line virtual method.
home()415 void format_object_base::home() {
416 }
417
418 //===----------------------------------------------------------------------===//
419 // raw_fd_ostream
420 //===----------------------------------------------------------------------===//
421
422 /// raw_fd_ostream - Open the specified file for writing. If an error
423 /// occurs, information about the error is put into ErrorInfo, and the
424 /// stream should be immediately destroyed; the string will be empty
425 /// if no error occurred.
raw_fd_ostream(const char * Filename,std::string & ErrorInfo,unsigned Flags)426 raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
427 unsigned Flags)
428 : Error(false), UseAtomicWrites(false), pos(0)
429 {
430 assert(Filename != 0 && "Filename is null");
431 // Verify that we don't have both "append" and "excl".
432 assert((!(Flags & F_Excl) || !(Flags & F_Append)) &&
433 "Cannot specify both 'excl' and 'append' file creation flags!");
434
435 ErrorInfo.clear();
436
437 // Handle "-" as stdout. Note that when we do this, we consider ourself
438 // the owner of stdout. This means that we can do things like close the
439 // file descriptor when we're done and set the "binary" flag globally.
440 if (Filename[0] == '-' && Filename[1] == 0) {
441 FD = STDOUT_FILENO;
442 // If user requested binary then put stdout into binary mode if
443 // possible.
444 if (Flags & F_Binary)
445 sys::Program::ChangeStdoutToBinary();
446 // Close stdout when we're done, to detect any output errors.
447 ShouldClose = true;
448 return;
449 }
450
451 int OpenFlags = O_WRONLY|O_CREAT;
452 #ifdef O_BINARY
453 if (Flags & F_Binary)
454 OpenFlags |= O_BINARY;
455 #endif
456
457 if (Flags & F_Append)
458 OpenFlags |= O_APPEND;
459 else
460 OpenFlags |= O_TRUNC;
461 if (Flags & F_Excl)
462 OpenFlags |= O_EXCL;
463
464 while ((FD = open(Filename, OpenFlags, 0664)) < 0) {
465 if (errno != EINTR) {
466 ErrorInfo = "Error opening output file '" + std::string(Filename) + "'";
467 ShouldClose = false;
468 return;
469 }
470 }
471
472 // Ok, we successfully opened the file, so it'll need to be closed.
473 ShouldClose = true;
474 }
475
476 /// raw_fd_ostream ctor - FD is the file descriptor that this writes to. If
477 /// ShouldClose is true, this closes the file when the stream is destroyed.
raw_fd_ostream(int fd,bool shouldClose,bool unbuffered)478 raw_fd_ostream::raw_fd_ostream(int fd, bool shouldClose, bool unbuffered)
479 : raw_ostream(unbuffered), FD(fd),
480 ShouldClose(shouldClose), Error(false), UseAtomicWrites(false) {
481 #ifdef O_BINARY
482 // Setting STDOUT and STDERR to binary mode is necessary in Win32
483 // to avoid undesirable linefeed conversion.
484 if (fd == STDOUT_FILENO || fd == STDERR_FILENO)
485 setmode(fd, O_BINARY);
486 #endif
487
488 // Get the starting position.
489 off_t loc = ::lseek(FD, 0, SEEK_CUR);
490 if (loc == (off_t)-1)
491 pos = 0;
492 else
493 pos = static_cast<uint64_t>(loc);
494 }
495
~raw_fd_ostream()496 raw_fd_ostream::~raw_fd_ostream() {
497 if (FD >= 0) {
498 flush();
499 if (ShouldClose)
500 while (::close(FD) != 0)
501 if (errno != EINTR) {
502 error_detected();
503 break;
504 }
505 }
506
507 #ifdef __MINGW32__
508 // On mingw, global dtors should not call exit().
509 // report_fatal_error() invokes exit(). We know report_fatal_error()
510 // might not write messages to stderr when any errors were detected
511 // on FD == 2.
512 if (FD == 2) return;
513 #endif
514
515 // If there are any pending errors, report them now. Clients wishing
516 // to avoid report_fatal_error calls should check for errors with
517 // has_error() and clear the error flag with clear_error() before
518 // destructing raw_ostream objects which may have errors.
519 if (has_error())
520 report_fatal_error("IO failure on output stream.");
521 }
522
523
write_impl(const char * Ptr,size_t Size)524 void raw_fd_ostream::write_impl(const char *Ptr, size_t Size) {
525 assert(FD >= 0 && "File already closed.");
526 pos += Size;
527
528 do {
529 ssize_t ret;
530
531 // Check whether we should attempt to use atomic writes.
532 if (LLVM_LIKELY(!UseAtomicWrites)) {
533 ret = ::write(FD, Ptr, Size);
534 } else {
535 // Use ::writev() where available.
536 #if defined(HAVE_WRITEV)
537 const void *Addr = static_cast<const void *>(Ptr);
538 struct iovec IOV = {const_cast<void *>(Addr), Size };
539 ret = ::writev(FD, &IOV, 1);
540 #else
541 ret = ::write(FD, Ptr, Size);
542 #endif
543 }
544
545 if (ret < 0) {
546 // If it's a recoverable error, swallow it and retry the write.
547 //
548 // Ideally we wouldn't ever see EAGAIN or EWOULDBLOCK here, since
549 // raw_ostream isn't designed to do non-blocking I/O. However, some
550 // programs, such as old versions of bjam, have mistakenly used
551 // O_NONBLOCK. For compatibility, emulate blocking semantics by
552 // spinning until the write succeeds. If you don't want spinning,
553 // don't use O_NONBLOCK file descriptors with raw_ostream.
554 if (errno == EINTR || errno == EAGAIN
555 #ifdef EWOULDBLOCK
556 || errno == EWOULDBLOCK
557 #endif
558 )
559 continue;
560
561 // Otherwise it's a non-recoverable error. Note it and quit.
562 error_detected();
563 break;
564 }
565
566 // The write may have written some or all of the data. Update the
567 // size and buffer pointer to reflect the remainder that needs
568 // to be written. If there are no bytes left, we're done.
569 Ptr += ret;
570 Size -= ret;
571 } while (Size > 0);
572 }
573
close()574 void raw_fd_ostream::close() {
575 assert(ShouldClose);
576 ShouldClose = false;
577 flush();
578 while (::close(FD) != 0)
579 if (errno != EINTR) {
580 error_detected();
581 break;
582 }
583 FD = -1;
584 }
585
seek(uint64_t off)586 uint64_t raw_fd_ostream::seek(uint64_t off) {
587 flush();
588 pos = ::lseek(FD, off, SEEK_SET);
589 if (pos != off)
590 error_detected();
591 return pos;
592 }
593
preferred_buffer_size() const594 size_t raw_fd_ostream::preferred_buffer_size() const {
595 #if !defined(_MSC_VER) && !defined(__MINGW32__) && !defined(__minix)
596 // Windows and Minix have no st_blksize.
597 assert(FD >= 0 && "File not yet open!");
598 struct stat statbuf;
599 if (fstat(FD, &statbuf) != 0)
600 return 0;
601
602 // If this is a terminal, don't use buffering. Line buffering
603 // would be a more traditional thing to do, but it's not worth
604 // the complexity.
605 if (S_ISCHR(statbuf.st_mode) && isatty(FD))
606 return 0;
607 // Return the preferred block size.
608 return statbuf.st_blksize;
609 #else
610 return raw_ostream::preferred_buffer_size();
611 #endif
612 }
613
changeColor(enum Colors colors,bool bold,bool bg)614 raw_ostream &raw_fd_ostream::changeColor(enum Colors colors, bool bold,
615 bool bg) {
616 if (sys::Process::ColorNeedsFlush())
617 flush();
618 const char *colorcode =
619 (colors == SAVEDCOLOR) ? sys::Process::OutputBold(bg)
620 : sys::Process::OutputColor(colors, bold, bg);
621 if (colorcode) {
622 size_t len = strlen(colorcode);
623 write(colorcode, len);
624 // don't account colors towards output characters
625 pos -= len;
626 }
627 return *this;
628 }
629
resetColor()630 raw_ostream &raw_fd_ostream::resetColor() {
631 if (sys::Process::ColorNeedsFlush())
632 flush();
633 const char *colorcode = sys::Process::ResetColor();
634 if (colorcode) {
635 size_t len = strlen(colorcode);
636 write(colorcode, len);
637 // don't account colors towards output characters
638 pos -= len;
639 }
640 return *this;
641 }
642
reverseColor()643 raw_ostream &raw_fd_ostream::reverseColor() {
644 if (sys::Process::ColorNeedsFlush())
645 flush();
646 const char *colorcode = sys::Process::OutputReverse();
647 if (colorcode) {
648 size_t len = strlen(colorcode);
649 write(colorcode, len);
650 // don't account colors towards output characters
651 pos -= len;
652 }
653 return *this;
654 }
655
is_displayed() const656 bool raw_fd_ostream::is_displayed() const {
657 return sys::Process::FileDescriptorIsDisplayed(FD);
658 }
659
has_colors() const660 bool raw_fd_ostream::has_colors() const {
661 return sys::Process::FileDescriptorHasColors(FD);
662 }
663
664 //===----------------------------------------------------------------------===//
665 // outs(), errs(), nulls()
666 //===----------------------------------------------------------------------===//
667
668 /// outs() - This returns a reference to a raw_ostream for standard output.
669 /// Use it like: outs() << "foo" << "bar";
outs()670 raw_ostream &llvm::outs() {
671 // Set buffer settings to model stdout behavior.
672 // Delete the file descriptor when the program exists, forcing error
673 // detection. If you don't want this behavior, don't use outs().
674 static raw_fd_ostream S(STDOUT_FILENO, true);
675 return S;
676 }
677
678 /// errs() - This returns a reference to a raw_ostream for standard error.
679 /// Use it like: errs() << "foo" << "bar";
errs()680 raw_ostream &llvm::errs() {
681 // Set standard error to be unbuffered by default.
682 static raw_fd_ostream S(STDERR_FILENO, false, true);
683 return S;
684 }
685
686 /// nulls() - This returns a reference to a raw_ostream which discards output.
nulls()687 raw_ostream &llvm::nulls() {
688 static raw_null_ostream S;
689 return S;
690 }
691
692
693 //===----------------------------------------------------------------------===//
694 // raw_string_ostream
695 //===----------------------------------------------------------------------===//
696
~raw_string_ostream()697 raw_string_ostream::~raw_string_ostream() {
698 flush();
699 }
700
write_impl(const char * Ptr,size_t Size)701 void raw_string_ostream::write_impl(const char *Ptr, size_t Size) {
702 OS.append(Ptr, Size);
703 }
704
705 //===----------------------------------------------------------------------===//
706 // raw_svector_ostream
707 //===----------------------------------------------------------------------===//
708
709 // The raw_svector_ostream implementation uses the SmallVector itself as the
710 // buffer for the raw_ostream. We guarantee that the raw_ostream buffer is
711 // always pointing past the end of the vector, but within the vector
712 // capacity. This allows raw_ostream to write directly into the correct place,
713 // and we only need to set the vector size when the data is flushed.
714
raw_svector_ostream(SmallVectorImpl<char> & O)715 raw_svector_ostream::raw_svector_ostream(SmallVectorImpl<char> &O) : OS(O) {
716 // Set up the initial external buffer. We make sure that the buffer has at
717 // least 128 bytes free; raw_ostream itself only requires 64, but we want to
718 // make sure that we don't grow the buffer unnecessarily on destruction (when
719 // the data is flushed). See the FIXME below.
720 OS.reserve(OS.size() + 128);
721 SetBuffer(OS.end(), OS.capacity() - OS.size());
722 }
723
~raw_svector_ostream()724 raw_svector_ostream::~raw_svector_ostream() {
725 // FIXME: Prevent resizing during this flush().
726 flush();
727 }
728
729 /// resync - This is called when the SmallVector we're appending to is changed
730 /// outside of the raw_svector_ostream's control. It is only safe to do this
731 /// if the raw_svector_ostream has previously been flushed.
resync()732 void raw_svector_ostream::resync() {
733 assert(GetNumBytesInBuffer() == 0 && "Didn't flush before mutating vector");
734
735 if (OS.capacity() - OS.size() < 64)
736 OS.reserve(OS.capacity() * 2);
737 SetBuffer(OS.end(), OS.capacity() - OS.size());
738 }
739
write_impl(const char * Ptr,size_t Size)740 void raw_svector_ostream::write_impl(const char *Ptr, size_t Size) {
741 // If we're writing bytes from the end of the buffer into the smallvector, we
742 // don't need to copy the bytes, just commit the bytes because they are
743 // already in the right place.
744 if (Ptr == OS.end()) {
745 assert(OS.size() + Size <= OS.capacity() && "Invalid write_impl() call!");
746 OS.set_size(OS.size() + Size);
747 } else {
748 assert(GetNumBytesInBuffer() == 0 &&
749 "Should be writing from buffer if some bytes in it");
750 // Otherwise, do copy the bytes.
751 OS.append(Ptr, Ptr+Size);
752 }
753
754 // Grow the vector if necessary.
755 if (OS.capacity() - OS.size() < 64)
756 OS.reserve(OS.capacity() * 2);
757
758 // Update the buffer position.
759 SetBuffer(OS.end(), OS.capacity() - OS.size());
760 }
761
current_pos() const762 uint64_t raw_svector_ostream::current_pos() const {
763 return OS.size();
764 }
765
str()766 StringRef raw_svector_ostream::str() {
767 flush();
768 return StringRef(OS.begin(), OS.size());
769 }
770
771 //===----------------------------------------------------------------------===//
772 // raw_null_ostream
773 //===----------------------------------------------------------------------===//
774
~raw_null_ostream()775 raw_null_ostream::~raw_null_ostream() {
776 #ifndef NDEBUG
777 // ~raw_ostream asserts that the buffer is empty. This isn't necessary
778 // with raw_null_ostream, but it's better to have raw_null_ostream follow
779 // the rules than to change the rules just for raw_null_ostream.
780 flush();
781 #endif
782 }
783
write_impl(const char * Ptr,size_t Size)784 void raw_null_ostream::write_impl(const char *Ptr, size_t Size) {
785 }
786
current_pos() const787 uint64_t raw_null_ostream::current_pos() const {
788 return 0;
789 }
790