OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR libstdc++/4150 (catastrophic performance decrease in C++ code) 

PR libstdc++/4150
        * include/std/std_streambuf.h (basic_streambuf::_M_set_indeterminate):
        Move to filebuf.
        (basic_streambuf::_M_set_determinate): Likewise.
        (basic_streambuf::_M_is_indeterminate): Likewise.
        * include/bits/std_fstream.h (basic_filebuf::_M_filepos): New
        non-static data member.
        (basic_filebuf::_M_underflow_common): New non-static member function.
        (basic_filebuf::_M_underflow, _M_uflow): Call it.
        (basic_filebuf::sync): Avoid useless seeking.
        (basic_filebuf::_M_set_indeterminate): Move here from streambuf.
        Set _M_filepos.
        (basic_filebuf::_M_set_determinate): Likewise.
        (basic_filebuf::_M_is_indeterminate): Likewise.
        * include/bits/fstream.tcc (basic_filebuf::_M_really_overflow): Seek
        back to _M_out_beg if necessary.
        (basic_filebuf::seekoff): Likewise.
        (basic_filebuf::_M_underflow_common): Generalization of old
        underflow().  Don't seek back to _M_in_beg.
        * src/ios.cc: Lose _GLIBCPP_AVOID_FSEEK stuff.
        * config/os/solaris/solaris2.?/bits/os_defines.h: Likewise.
        * config/os/bsd/freebsd/bits/os_defines.h: Likewise.
        * config/os/mingw32/bits/os_defines.h: Likewise.
        * testsuite/27_io/filebuf_virtuals.cc (test05): Don't overspecify
        ungetc test.

From-SVN: r52635
This commit is contained in:
Jason Merrill 2002-04-22 16:28:37 -04:00 committed by Jason Merrill
parent f38b229cc6
commit c0be689711
11 changed files with 118 additions and 86 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,31 @@
2002-04-20 Jason Merrill <jason@redhat.com>
PR libstdc++/4150
* include/std/std_streambuf.h (basic_streambuf::_M_set_indeterminate):
Move to filebuf.
(basic_streambuf::_M_set_determinate): Likewise.
(basic_streambuf::_M_is_indeterminate): Likewise.
* include/bits/std_fstream.h (basic_filebuf::_M_filepos): New
non-static data member.
(basic_filebuf::_M_underflow_common): New non-static member function.
(basic_filebuf::_M_underflow, _M_uflow): Call it.
(basic_filebuf::sync): Avoid useless seeking.
(basic_filebuf::_M_set_indeterminate): Move here from streambuf.
Set _M_filepos.
(basic_filebuf::_M_set_determinate): Likewise.
(basic_filebuf::_M_is_indeterminate): Likewise.
* include/bits/fstream.tcc (basic_filebuf::_M_really_overflow): Seek
back to _M_out_beg if necessary.
(basic_filebuf::seekoff): Likewise.
(basic_filebuf::_M_underflow_common): Generalization of old
underflow(). Don't seek back to _M_in_beg.
* src/ios.cc: Lose _GLIBCPP_AVOID_FSEEK stuff.
* config/os/solaris/solaris2.?/bits/os_defines.h: Likewise.
* config/os/bsd/freebsd/bits/os_defines.h: Likewise.
* config/os/mingw32/bits/os_defines.h: Likewise.
* testsuite/27_io/filebuf_virtuals.cc (test05): Don't overspecify
ungetc test.
2002-04-22 Benjamin Kosnik <bkoz@redhat.com>
* include/bits/istream.tcc (istream::read): Fix.

2
libstdc++-v3/config/os/bsd/freebsd/bits/os_defines.h
View File

@ -36,6 +36,4 @@
#define __glibcpp_long_double_bits __glibcpp_double_bits
#define _GLIBCPP_AVOID_FSEEK 1
#endif

3
libstdc++-v3/config/os/mingw32/bits/os_defines.h
View File

@ -34,7 +34,4 @@
// System-specific #define, typedefs, corrections, etc, go here. This
// file will come before all others.
#define _GLIBCPP_AVOID_FSEEK 1
#endif

2
libstdc++-v3/config/os/solaris/solaris2.5/bits/os_defines.h
View File

@ -33,8 +33,6 @@
// System-specific #define, typedefs, corrections, etc, go here. This
// file will come before all others.
#define _GLIBCPP_AVOID_FSEEK 1
// These are typedefs which libio assumes are already in place (because
// they really are, under Linux).
#define __off_t off_t

2
libstdc++-v3/config/os/solaris/solaris2.6/bits/os_defines.h
View File

@ -33,8 +33,6 @@
// System-specific #define, typedefs, corrections, etc, go here. This
// file will come before all others.
#define _GLIBCPP_AVOID_FSEEK 1
// These are typedefs which libio assumes are already in place (because
// they really are, under Linux).
#define __off_t off_t

2
libstdc++-v3/config/os/solaris/solaris2.7/bits/os_defines.h
View File

@ -33,8 +33,6 @@
// System-specific #define, typedefs, corrections, etc, go here. This
// file will come before all others.
#define _GLIBCPP_AVOID_FSEEK 1
// These are typedefs which libio assumes are already in place (because
// they really are, under Linux).
#define __off_t off_t

38
libstdc++-v3/include/bits/fstream.tcc
View File

@ -206,7 +206,7 @@ namespace std
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::int_type
basic_filebuf<_CharT, _Traits>::
underflow()
_M_underflow_common(bool __bump)
{
int_type __ret = traits_type::eof();
bool __testin = _M_mode & ios_base::in;
@ -232,12 +232,8 @@ namespace std
{
if (__testout)
_M_really_overflow();
#if _GLIBCPP_AVOID_FSEEK
else if ((_M_in_cur - _M_in_beg) == 1)
_M_file.sys_getc();
#endif
else
_M_file.seekoff(_M_in_cur - _M_in_beg,
else if (_M_in_cur != _M_filepos)
_M_file.seekoff(_M_in_cur - _M_filepos,
ios_base::cur, ios_base::in);
}
@ -280,16 +276,16 @@ namespace std
if (__testout)
_M_out_cur = _M_in_cur;
__ret = traits_type::to_int_type(*_M_in_cur);
#if _GLIBCPP_AVOID_FSEEK
if (__elen == 1)
_M_file.sys_ungetc(*_M_in_cur);
else
if (__bump)
_M_in_cur_move(1);
else if (_M_buf_size == 1)
{
#endif
_M_file.seekoff(-__elen, ios_base::cur, ios_base::in);
#if _GLIBCPP_AVOID_FSEEK
// If we are synced with stdio, we have to unget the
// character we just read so that the file pointer
// doesn't move.
_M_file.sys_ungetc(*_M_in_cur);
_M_set_indeterminate();
}
#endif
}
}
}
@ -464,6 +460,15 @@ namespace std
streamsize __elen = 0;
streamsize __plen = 0;
// Need to restore current position. The position of the external
// byte sequence (_M_file) corresponds to _M_filepos, and we need
// to move it to _M_out_beg for the write.
if (_M_filepos && _M_filepos != _M_out_beg)
{
off_type __off = _M_out_beg - _M_filepos;
_M_file.seekoff(__off, ios_base::cur);
}
// Convert internal buffer to external representation, output.
// NB: In the unbuffered case, no internal buffer exists.
if (!__testunbuffered)
@ -551,9 +556,8 @@ namespace std
_M_output_unshift();
}
//in
// NB: underflow() rewinds the external buffer.
else if (__testget && __way == ios_base::cur)
__computed_off += _M_in_cur - _M_in_beg;
__computed_off += _M_in_cur - _M_filepos;
__ret = _M_file.seekoff(__computed_off, __way, __mode);
_M_set_indeterminate();

74
libstdc++-v3/include/std/std_fstream.h
View File

@ -93,6 +93,10 @@ namespace std
// XXX Needed?
bool _M_last_overflowed;
// The position in the buffer corresponding to the external file
// pointer.
char_type* _M_filepos;
public:
// Constructors/destructor:
basic_filebuf();
@ -137,8 +141,21 @@ namespace std
// underflow() and uflow() functions are called to get the next
// charater from the real input source when the buffer is empty.
// Buffered input uses underflow()
// The only difference between underflow() and uflow() is that the
// latter bumps _M_in_cur after the read. In the sync_with_stdio
// case, this is important, as we need to unget the read character in
// the underflow() case in order to maintain synchronization. So
// instead of calling underflow() from uflow(), we create a common
// subroutine to do the real work.
int_type
_M_underflow_common(bool __bump);
virtual int_type
underflow();
underflow() { return _M_underflow_common(false); }
virtual int_type
uflow() { return _M_underflow_common(true); }
virtual int_type
pbackfail(int_type __c = _Traits::eof());
@ -189,14 +206,11 @@ namespace std
// the file position with the external file.
if (__testput && !_M_file.sync())
{
// Need to restore current position. This interpreted as
// the position of the external byte sequence (_M_file)
// plus the offset in the current internal buffer
// (_M_out_beg - _M_out_cur)
streamoff __cur = _M_file.seekoff(0, ios_base::cur);
off_type __off = _M_out_cur - _M_out_beg;
// Need to restore current position after the write.
off_type __off = _M_out_cur - _M_out_end;
_M_really_overflow();
_M_file.seekpos(__cur + __off);
if (__off)
_M_file.seekoff(__off, ios_base::cur);
}
_M_last_overflowed = false;
return 0;
@ -235,6 +249,50 @@ namespace std
void
_M_output_unshift();
// These three functions are used to clarify internal buffer
// maintenance. After an overflow, or after a seekoff call that
// started at beg or end, or possibly when the stream becomes
// unbuffered, and a myrid other obscure corner cases, the
// internal buffer does not truly reflect the contents of the
// external buffer. At this point, for whatever reason, it is in
// an indeterminate state.
void
_M_set_indeterminate(void)
{
if (_M_mode & ios_base::in)
this->setg(_M_buf, _M_buf, _M_buf);
if (_M_mode & ios_base::out)
this->setp(_M_buf, _M_buf);
_M_filepos = _M_in_end;
}
void
_M_set_determinate(off_type __off)
{
bool __testin = _M_mode & ios_base::in;
bool __testout = _M_mode & ios_base::out;
if (__testin)
this->setg(_M_buf, _M_buf, _M_buf + __off);
if (__testout)
this->setp(_M_buf, _M_buf + __off);
_M_filepos = _M_in_end;
}
bool
_M_is_indeterminate(void)
{
bool __ret = false;
// Don't return true if unbuffered.
if (_M_buf)
{
if (_M_mode & ios_base::in)
__ret = _M_in_beg == _M_in_cur && _M_in_cur == _M_in_end;
if (_M_mode & ios_base::out)
__ret = _M_out_beg == _M_out_cur && _M_out_cur == _M_out_end;
}
return __ret;
}
};

42
libstdc++-v3/include/std/std_streambuf.h
View File

@ -231,48 +231,6 @@ namespace std
return __ret;
}
// These three functions are used to clarify internal buffer
// maintenance. After an overflow, or after a seekoff call that
// started at beg or end, or possibly when the stream becomes
// unbuffered, and a myrid other obscure corner cases, the
// internal buffer does not truly reflect the contents of the
// external buffer. At this point, for whatever reason, it is in
// an indeterminate state.
void
_M_set_indeterminate(void)
{
if (_M_mode & ios_base::in)
this->setg(_M_buf, _M_buf, _M_buf);
if (_M_mode & ios_base::out)
this->setp(_M_buf, _M_buf);
}
void
_M_set_determinate(off_type __off)
{
bool __testin = _M_mode & ios_base::in;
bool __testout = _M_mode & ios_base::out;
if (__testin)
this->setg(_M_buf, _M_buf, _M_buf + __off);
if (__testout)
this->setp(_M_buf, _M_buf + __off);
}
bool
_M_is_indeterminate(void)
{
bool __ret = false;
// Don't return true if unbuffered.
if (_M_buf)
{
if (_M_mode & ios_base::in)
__ret = _M_in_beg == _M_in_cur && _M_in_cur == _M_in_end;
if (_M_mode & ios_base::out)
__ret = _M_out_beg == _M_out_cur && _M_out_cur == _M_out_end;
}
return __ret;
}
public:
virtual
~basic_streambuf()

8
libstdc++-v3/src/ios.cc
View File

@ -150,14 +150,6 @@ namespace std
int __out_bufsize = __sync ? 0 : static_cast<int>(BUFSIZ);
int __in_bufsize = __sync ? 1 : static_cast<int>(BUFSIZ);
#if _GLIBCPP_AVOID_FSEEK
// Platforms that prefer to avoid fseek() calls on streams only
// get their desire when the C++-layer input buffer size is 1.
// This hack hurts performance but keeps correctness across
// all types of streams that might be attached to (e.g.) cin.
__in_bufsize = 1;
#endif
// NB: The file globals.cc creates the four standard files
// with NULL buffers. At this point, we swap out the dummy NULL
// [io]stream objects and buffers with the real deal.

3
libstdc++-v3/testsuite/27_io/filebuf_virtuals.cc
View File

@ -444,6 +444,9 @@ void test05()
strmsz_1 = fb_03.sputn("because because because. . .", 28);
VERIFY( strmsz_1 == 28 );
c1 = fb_03.sungetc();
// Defect? retval of sungetc is not necessarily the character ungotten.
// So re-get it.
c1 = fb_03.sgetc();
fb_03.pubsync();
c3 = fb_03.sgetc();
VERIFY( c1 == c3 );