src/compiler/glsl/glcpp/pp.c

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include <assert.h>
  25 #include <string.h>
  26 #include <ctype.h>
  27 #include "glcpp.h"
  28
  29 void
  30 glcpp_error (YYLTYPE *locp, glcpp_parser_t *parser, const char *fmt, ...)
  31 {
  32         va_list ap;
  33
  34         parser->error = 1;
  35         _mesa_string_buffer_printf(parser->info_log,
  36                                    "%u:%u(%u): "
  37                                    "preprocessor error: ",
  38                                    locp->source,
  39                                    locp->first_line,
  40                                    locp->first_column);
  41         va_start(ap, fmt);
  42         _mesa_string_buffer_vprintf(parser->info_log, fmt, ap);
  43         va_end(ap);
  44         _mesa_string_buffer_append_char(parser->info_log, '\n');
  45 }
  46
  47 void
  48 glcpp_warning (YYLTYPE *locp, glcpp_parser_t *parser, const char *fmt, ...)
  49 {
  50         va_list ap;
  51
  52         _mesa_string_buffer_printf(parser->info_log,
  53                                      "%u:%u(%u): "
  54                                      "preprocessor warning: ",
  55                                      locp->source,
  56                                      locp->first_line,
  57                                      locp->first_column);
  58         va_start(ap, fmt);
  59         _mesa_string_buffer_vprintf(parser->info_log, fmt, ap);
  60         va_end(ap);
  61         _mesa_string_buffer_append_char(parser->info_log, '\n');
  62 }
  63
  64 /* Given str, (that's expected to start with a newline terminator of some
  65  * sort), return a pointer to the first character in str after the newline.
  66  *
  67  * A newline terminator can be any of the following sequences:
  68  *
  69  *      "\r\n"
  70  *      "\n\r"
  71  *      "\n"
  72  *      "\r"
  73  *
  74  * And the longest such sequence will be skipped.
  75  */
  76 static const char *
  77 skip_newline (const char *str)
  78 {
  79         const char *ret = str;
  80
  81         if (ret == NULL)
  82                 return ret;
  83
  84         if (*ret == '\0')
  85                 return ret;
  86
  87         if (*ret == '\r') {
  88                 ret++;
  89                 if (*ret && *ret == '\n')
  90                         ret++;
  91         } else if (*ret == '\n') {
  92                 ret++;
  93                 if (*ret && *ret == '\r')
  94                         ret++;
  95         }
  96
  97         return ret;
  98 }
  99
 100 /* Initial output buffer size, 4096 minus ralloc() overhead. It was selected
 101  * to minimize total amount of allocated memory during shader-db run.
 102  */
 103 #define INITIAL_PP_OUTPUT_BUF_SIZE 4048
 104
 105 /* Remove any line continuation characters in the shader, (whether in
 106  * preprocessing directives or in GLSL code).
 107  */
 108 static char *
 109 remove_line_continuations(glcpp_parser_t *ctx, const char *shader)
 110 {
 111         struct _mesa_string_buffer *sb =
 112                 _mesa_string_buffer_create(ctx, INITIAL_PP_OUTPUT_BUF_SIZE);
 113
 114         const char *backslash, *newline, *search_start;
 115         const char *cr, *lf;
 116         char newline_separator[3];
 117         int collapsed_newlines = 0;
 118         int separator_len;
 119
 120         backslash = strchr(shader, '\\');
 121
 122         /* No line continuations were found in this shader, our job is done */
 123         if (backslash == NULL)
 124                 return (char *) shader;
 125
 126         search_start = shader;
 127
 128         /* Determine what flavor of newlines this shader is using. GLSL
 129          * provides for 4 different possible ways to separate lines, (using
 130          * one or two characters):
 131          *
 132          *      "\n" (line-feed, like Linux, Unix, and new Mac OS)
 133          *      "\r" (carriage-return, like old Mac files)
 134          *      "\r\n" (carriage-return + line-feed, like DOS files)
 135          *      "\n\r" (line-feed + carriage-return, like nothing, really)
 136          *
 137          * This code explicitly supports a shader that uses a mixture of
 138          * newline terminators and will properly handle line continuation
 139          * backslashes followed by any of the above.
 140          *
 141          * But, since we must also insert additional newlines in the output
 142          * (for any collapsed lines) we attempt to maintain consistency by
 143          * examining the first encountered newline terminator, and using the
 144          * same terminator for any newlines we insert.
 145          */
 146         cr = strchr(search_start, '\r');
 147         lf = strchr(search_start, '\n');
 148
 149         newline_separator[0] = '\n';
 150         newline_separator[1] = '\0';
 151         newline_separator[2] = '\0';
 152
 153         if (cr == NULL) {
 154                 /* Nothing to do. */
 155         } else if (lf == NULL) {
 156                 newline_separator[0] = '\r';
 157         } else if (lf == cr + 1) {
 158                 newline_separator[0] = '\r';
 159                 newline_separator[1] = '\n';
 160         } else if (cr == lf + 1) {
 161                 newline_separator[0] = '\n';
 162                 newline_separator[1] = '\r';
 163         }
 164         separator_len = strlen(newline_separator);
 165
 166         while (true) {
 167                 /* If we have previously collapsed any line-continuations,
 168                  * then we want to insert additional newlines at the next
 169                  * occurrence of a newline character to avoid changing any
 170                  * line numbers.
 171                  */
 172                 if (collapsed_newlines) {
 173                         cr = strchr (search_start, '\r');
 174                         lf = strchr (search_start, '\n');
 175                         if (cr && lf)
 176                                 newline = cr < lf ? cr : lf;
 177                         else if (cr)
 178                                 newline = cr;
 179                         else
 180                                 newline = lf;
 181                         if (newline &&
 182                             (backslash == NULL || newline < backslash))
 183                         {
 184                                 _mesa_string_buffer_append_len(sb, shader,
 185                                                                newline - shader + 1);
 186                                 while (collapsed_newlines) {
 187                                         _mesa_string_buffer_append_len(sb,
 188                                                                        newline_separator,
 189                                                                        separator_len);
 190                                         collapsed_newlines--;
 191                                 }
 192                                 shader = skip_newline (newline);
 193                                 search_start = shader;
 194                         }
 195                 }
 196
 197                 search_start = backslash + 1;
 198
 199                 if (backslash == NULL)
 200                         break;
 201
 202                 /* At each line continuation, (backslash followed by a
 203                  * newline), copy all preceding text to the output, then
 204                  * advance the shader pointer to the character after the
 205                  * newline.
 206                  */
 207                 if (backslash[1] == '\r' || backslash[1] == '\n')
 208                 {
 209                         collapsed_newlines++;
 210                         _mesa_string_buffer_append_len(sb, shader, backslash - shader);
 211                         shader = skip_newline (backslash + 1);
 212                         search_start = shader;
 213                 }
 214
 215                 backslash = strchr(search_start, '\\');
 216         }
 217
 218         _mesa_string_buffer_append(sb, shader);
 219
 220         return sb->buf;
 221 }
 222
 223 int
 224 glcpp_preprocess(void *ralloc_ctx, const char **shader, char **info_log,
 225                  glcpp_extension_iterator extensions, void *state,
 226                  struct gl_context *gl_ctx)
 227 {
 228         int errors;
 229         glcpp_parser_t *parser =
 230                 glcpp_parser_create(&gl_ctx->Extensions, extensions, state, gl_ctx->API);
 231
 232         if (! gl_ctx->Const.DisableGLSLLineContinuations)
 233                 *shader = remove_line_continuations(parser, *shader);
 234
 235         glcpp_lex_set_source_string (parser, *shader);
 236
 237         glcpp_parser_parse (parser);
 238
 239         if (parser->skip_stack)
 240                 glcpp_error (&parser->skip_stack->loc, parser, "Unterminated #if\n");
 241
 242         glcpp_parser_resolve_implicit_version(parser);
 243
 244         ralloc_strcat(info_log, parser->info_log->buf);
 245
 246         /* Crimp the buffer first, to conserve memory */
 247         _mesa_string_buffer_crimp_to_fit(parser->output);
 248
 249         ralloc_steal(ralloc_ctx, parser->output->buf);
 250         *shader = parser->output->buf;
 251
 252         errors = parser->error;
 253         glcpp_parser_destroy (parser);
 254         return errors;
 255 }