src/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 #include "main/core.h" /* for isblank() on MSVC */
  29
  30 void
  31 glcpp_error (YYLTYPE *locp, glcpp_parser_t *parser, const char *fmt, ...)
  32 {
  33         va_list ap;
  34
  35         parser->error = 1;
  36         ralloc_asprintf_rewrite_tail(&parser->info_log,
  37                                      &parser->info_log_length,
  38                                      "%u:%u(%u): "
  39                                      "preprocessor error: ",
  40                                      locp->source,
  41                                      locp->first_line,
  42                                      locp->first_column);
  43         va_start(ap, fmt);
  44         ralloc_vasprintf_rewrite_tail(&parser->info_log,
  45                                       &parser->info_log_length,
  46                                       fmt, ap);
  47         va_end(ap);
  48         ralloc_asprintf_rewrite_tail(&parser->info_log,
  49                                      &parser->info_log_length, "\n");
  50 }
  51
  52 void
  53 glcpp_warning (YYLTYPE *locp, glcpp_parser_t *parser, const char *fmt, ...)
  54 {
  55         va_list ap;
  56
  57         ralloc_asprintf_rewrite_tail(&parser->info_log,
  58                                      &parser->info_log_length,
  59                                      "%u:%u(%u): "
  60                                      "preprocessor warning: ",
  61                                      locp->source,
  62                                      locp->first_line,
  63                                      locp->first_column);
  64         va_start(ap, fmt);
  65         ralloc_vasprintf_rewrite_tail(&parser->info_log,
  66                                       &parser->info_log_length,
  67                                       fmt, ap);
  68         va_end(ap);
  69         ralloc_asprintf_rewrite_tail(&parser->info_log,
  70                                      &parser->info_log_length, "\n");
  71 }
  72
  73 /* Searches backwards for '^ *#' from a given starting point. */
  74 static int
  75 in_directive(const char *shader, const char *ptr)
  76 {
  77         assert(ptr >= shader);
  78
  79         /* Search backwards for '#'. If we find a \n first, it doesn't count */
  80         for (; ptr >= shader && *ptr != '#'; ptr--) {
  81                 if (*ptr == '\n')
  82                         return 0;
  83         }
  84         if (ptr >= shader) {
  85                 /* Found '#'...look for spaces preceded by a newline */
  86                 for (ptr--; ptr >= shader && isblank(*ptr); ptr--);
  87                 // FIXME: I don't think the '\n' case can happen
  88                 if (ptr < shader || *ptr == '\n')
  89                         return 1;
  90         }
  91         return 0;
  92 }
  93
  94 /* Remove any line continuation characters in preprocessing directives.
  95  * However, ignore any in GLSL code, as "There is no line continuation
  96  * character" (1.30 page 9) in GLSL.
  97  */
  98 static char *
  99 remove_line_continuations(glcpp_parser_t *ctx, const char *shader)
 100 {
 101         int in_continued_line = 0;
 102         int extra_newlines = 0;
 103         char *clean = ralloc_strdup(ctx, "");
 104         const char *search_start = shader;
 105         const char *newline;
 106         while ((newline = strchr(search_start, '\n')) != NULL) {
 107                 const char *backslash = NULL;
 108
 109                 /* # of characters preceding the newline. */
 110                 int n = newline - shader;
 111
 112                 /* Find the preceding '\', if it exists */
 113                 if (n >= 1 && newline[-1] == '\\')
 114                         backslash = newline - 1;
 115                 else if (n >= 2 && newline[-1] == '\r' && newline[-2] == '\\')
 116                         backslash = newline - 2;
 117
 118                 /* Double backslashes don't count (the backslash is escaped) */
 119                 if (backslash != NULL && backslash[-1] == '\\') {
 120                         backslash = NULL;
 121                 }
 122
 123                 if (backslash != NULL) {
 124                         /* We found a line continuation, but do we care? */
 125                         if (!in_continued_line) {
 126                                 if (in_directive(shader, backslash)) {
 127                                         in_continued_line = 1;
 128                                         extra_newlines = 0;
 129                                 }
 130                         }
 131                         if (in_continued_line) {
 132                                 /* Copy everything before the \ */
 133                                 ralloc_strncat(&clean, shader, backslash - shader);
 134                                 shader = newline + 1;
 135                                 extra_newlines++;
 136                         }
 137                 } else if (in_continued_line) {
 138                         /* Copy everything up to and including the \n */
 139                         ralloc_strncat(&clean, shader, newline - shader + 1);
 140                         shader = newline + 1;
 141                         /* Output extra newlines to make line numbers match */
 142                         for (; extra_newlines > 0; extra_newlines--)
 143                                 ralloc_strcat(&clean, "\n");
 144                         in_continued_line = 0;
 145                 }
 146                 search_start = newline + 1;
 147         }
 148         ralloc_strcat(&clean, shader);
 149         return clean;
 150 }
 151
 152 int
 153 glcpp_preprocess(void *ralloc_ctx, const char **shader, char **info_log,
 154            const struct gl_extensions *extensions, struct gl_context *gl_ctx)
 155 {
 156         int errors;
 157         glcpp_parser_t *parser = glcpp_parser_create (extensions, gl_ctx->API);
 158
 159         if (! gl_ctx->Const.DisableGLSLLineContinuations)
 160                 *shader = remove_line_continuations(parser, *shader);
 161
 162         glcpp_lex_set_source_string (parser, *shader);
 163
 164         glcpp_parser_parse (parser);
 165
 166         if (parser->skip_stack)
 167                 glcpp_error (&parser->skip_stack->loc, parser, "Unterminated #if\n");
 168
 169         ralloc_strcat(info_log, parser->info_log);
 170
 171         ralloc_steal(ralloc_ctx, parser->output);
 172         *shader = parser->output;
 173
 174         errors = parser->error;
 175         glcpp_parser_destroy (parser);
 176         return errors;
 177 }