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