| Message ID | 20240822182508.621-1-amonakov@ispras.ru |
|---|---|
| State | New |
| Headers | show |
| Series | libcpp: bump padding size in _cpp_convert_input [PR116458] | expand |
On Thu, Aug 22, 2024 at 8:25 PM Alexander Monakov <amonakov@ispras.ru> wrote: > > The recently introduced search_line_fast_ssse3 raised padding > requirement from 16 to 64, which was adjusted in read_file_guts, > but the corresponding ' + 16' in _cpp_convert_input was overlooked. OK > libcpp/ChangeLog: > > PR preprocessor/116458 > * charset.cc (_cpp_convert_input): Bump padding to 64 if > HAVE_SSSE3. > --- > libcpp/charset.cc | 21 ++++++++++++--------- > 1 file changed, 12 insertions(+), 9 deletions(-) > > diff --git a/libcpp/charset.cc b/libcpp/charset.cc > index d58319a500..79072877cb 100644 > --- a/libcpp/charset.cc > +++ b/libcpp/charset.cc > @@ -3093,6 +3093,7 @@ _cpp_convert_input (cpp_reader *pfile, const char *input_charset, > struct cset_converter input_cset; > struct _cpp_strbuf to; > unsigned char *buffer; > + size_t pad; > > input_cset = init_iconv_desc (pfile, SOURCE_CHARSET, input_charset); > if (input_cset.func == convert_no_conversion) > @@ -3129,16 +3130,18 @@ _cpp_convert_input (cpp_reader *pfile, const char *input_charset, > } > } > > +#ifdef HAVE_SSSE3 > + pad = 64; > +#else > + pad = 16; > +#endif > /* Resize buffer if we allocated substantially too much, or if we > - haven't enough space for the \n-terminator or following > - 15 bytes of padding (used to quiet warnings from valgrind or > - Address Sanitizer, when the optimized lexer accesses aligned > - 16-byte memory chunks, including the bytes after the malloced, > - area, and stops lexing on '\n'). */ > - if (to.len + 4096 < to.asize || to.len + 16 > to.asize) > - to.text = XRESIZEVEC (uchar, to.text, to.len + 16); > - > - memset (to.text + to.len, '\0', 16); > + don't have enough space for the following padding, which allows > + search_line_fast to use (possibly misaligned) vector loads. */ > + if (to.len + 4096 < to.asize || to.len + pad > to.asize) > + to.text = XRESIZEVEC (uchar, to.text, to.len + pad); > + > + memset (to.text + to.len, '\0', pad); > > /* If the file is using old-school Mac line endings (\r only), > terminate with another \r, not an \n, so that we do not mistake > -- > 2.46.0 >
diff --git a/libcpp/charset.cc b/libcpp/charset.cc index d58319a500..79072877cb 100644 --- a/libcpp/charset.cc +++ b/libcpp/charset.cc @@ -3093,6 +3093,7 @@ _cpp_convert_input (cpp_reader *pfile, const char *input_charset, struct cset_converter input_cset; struct _cpp_strbuf to; unsigned char *buffer; + size_t pad; input_cset = init_iconv_desc (pfile, SOURCE_CHARSET, input_charset); if (input_cset.func == convert_no_conversion) @@ -3129,16 +3130,18 @@ _cpp_convert_input (cpp_reader *pfile, const char *input_charset, } } +#ifdef HAVE_SSSE3 + pad = 64; +#else + pad = 16; +#endif /* Resize buffer if we allocated substantially too much, or if we - haven't enough space for the \n-terminator or following - 15 bytes of padding (used to quiet warnings from valgrind or - Address Sanitizer, when the optimized lexer accesses aligned - 16-byte memory chunks, including the bytes after the malloced, - area, and stops lexing on '\n'). */ - if (to.len + 4096 < to.asize || to.len + 16 > to.asize) - to.text = XRESIZEVEC (uchar, to.text, to.len + 16); - - memset (to.text + to.len, '\0', 16); + don't have enough space for the following padding, which allows + search_line_fast to use (possibly misaligned) vector loads. */ + if (to.len + 4096 < to.asize || to.len + pad > to.asize) + to.text = XRESIZEVEC (uchar, to.text, to.len + pad); + + memset (to.text + to.len, '\0', pad); /* If the file is using old-school Mac line endings (\r only), terminate with another \r, not an \n, so that we do not mistake