slang_preprocess.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
 * Mesa 3-D graphics library
 * Version:  6.5.2
 *
 * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file slang_preprocess.c
 * slang preprocessor
 * \author Michal Krol
 */

#include "main/imports.h"
#include "shader/grammar/grammar_mesa.h"
#include "slang_preprocess.h"

LONGSTRING static const char *slang_pp_directives_syn =
#include "library/slang_pp_directives_syn.h"
;

LONGSTRING static const char *slang_pp_expression_syn =
#include "library/slang_pp_expression_syn.h"
;

LONGSTRING static const char *slang_pp_version_syn =
#include "library/slang_pp_version_syn.h"
;

static GLvoid
grammar_error_to_log (slang_info_log *log)
{
   char buf[1024];
   GLint pos;

   grammar_get_last_error ((byte *) (buf), sizeof (buf), &pos);
   slang_info_log_error (log, buf);
}

GLboolean
_slang_preprocess_version (const char *text, GLuint *version, GLuint *eaten, slang_info_log *log)
{
   grammar id;
   byte *prod, *I;
   unsigned int size;

   id = grammar_load_from_text ((const byte *) (slang_pp_version_syn));
   if (id == 0) {
      grammar_error_to_log (log);
      return GL_FALSE;
   }

   if (!grammar_fast_check (id, (const byte *) (text), &prod, &size, 8)) {
      grammar_error_to_log (log);
      grammar_destroy (id);
      return GL_FALSE;
   }

   /* there can be multiple #version directives - grab the last one */
   I = &prod[size - 6];
   *version = (GLuint) (I[0]) + (GLuint) (I[1]) * 100;
   *eaten = (GLuint) (I[2]) + ((GLuint) (I[3]) << 8) + ((GLuint) (I[4]) << 16) + ((GLuint) (I[5]) << 24);

   grammar_destroy (id);
   grammar_alloc_free (prod);
   return GL_TRUE;
}

/*
 * The preprocessor does the following work.
 * 1. Remove comments. Each comment block is replaced with a single space and if the
 *    block contains new-lines, they are preserved. This ensures that line numbers
 *    stay the same and if a comment block delimits two tokens, the are delitmited
 *    by the space after comment removal.
 * 2. Remove preprocessor directives from the source string, checking their syntax and
 *    executing them if appropriate. Again, new-lines are preserved.
 * 3. Expand macros.
 * 4. Tokenize the source string by ensuring there is at least one space between every
 *    two adjacent tokens.
 */

#define PP_ANNOTATE 0

static GLvoid
pp_annotate (slang_string *output, const char *fmt, ...)
{
#if PP_ANNOTATE
   va_list va;
   char buffer[1024];

   va_start (va, fmt);
   _mesa_vsprintf (buffer, fmt, va);
   va_end (va);
   slang_string_pushs (output, buffer, _mesa_strlen (buffer));
#else
   (GLvoid) (output);
   (GLvoid) (fmt);
#endif
}

 /*
 * The expression is executed on a fixed-sized stack. The PUSH macro makes a runtime
 * check if the stack is not overflown by too complex expressions. In that situation the
 * GLSL preprocessor should report internal compiler error.
 * The BINARYDIV makes a runtime check if the divider is not 0. If it is, it reports
 * compilation error.
 */

#define EXECUTION_STACK_SIZE 1024

#define PUSH(x)\
   do {\
      if (sp == 0) {\
         slang_info_log_error (elog, "internal compiler error: preprocessor execution stack overflow.");\
         return GL_FALSE;\
      }\
      stack[--sp] = x;\
   } while (GL_FALSE)

#define POP(x)\
   do {\
      assert (sp < EXECUTION_STACK_SIZE);\
      x = stack[sp++];\
   } while (GL_FALSE)

#define BINARY(op)\
   do {\
      GLint a, b;\
      POP(b);\
      POP(a);\
      PUSH(a op b);\
   } while (GL_FALSE)

#define BINARYDIV(op)\
   do {\
      GLint a, b;\
      POP(b);\
      POP(a);\
      if (b == 0) {\
         slang_info_log_error (elog, "division by zero in preprocessor expression.");\
         return GL_FALSE;\
      }\
      PUSH(a op b);\
   } while (GL_FALSE)

#define UNARY(op)\
   do {\
      GLint a;\
      POP(a);\
      PUSH(op a);\
   } while (GL_FALSE)

#define OP_END          0
#define OP_PUSHINT      1
#define OP_LOGICALOR    2
#define OP_LOGICALAND   3
#define OP_OR           4
#define OP_XOR          5
#define OP_AND          6
#define OP_EQUAL        7
#define OP_NOTEQUAL     8
#define OP_LESSEQUAL    9
#define OP_GREATEREQUAL 10
#define OP_LESS         11
#define OP_GREATER      12
#define OP_LEFTSHIFT    13
#define OP_RIGHTSHIFT   14
#define OP_ADD          15
#define OP_SUBTRACT     16
#define OP_MULTIPLY     17
#define OP_DIVIDE       18
#define OP_MODULUS      19
#define OP_PLUS         20
#define OP_MINUS        21
#define OP_NEGATE       22
#define OP_COMPLEMENT   23

static GLboolean
execute_expression (slang_string *output, const byte *code, GLuint *pi, GLint *result,
                    slang_info_log *elog)
{
   GLuint i = *pi;
   GLint stack[EXECUTION_STACK_SIZE];
   GLuint sp = EXECUTION_STACK_SIZE;

   while (code[i] != OP_END) {
      switch (code[i++]) {
         case OP_PUSHINT:
            i++;
            PUSH(_mesa_atoi ((const char *) (&code[i])));
            i += _mesa_strlen ((const char *) (&code[i])) + 1;
            break;
         case OP_LOGICALOR:
            BINARY(||);
            break;
         case OP_LOGICALAND:
            BINARY(&&);
            break;
         case OP_OR:
            BINARY(|);
            break;
         case OP_XOR:
            BINARY(^);
            break;
         case OP_AND:
            BINARY(&);
            break;
         case OP_EQUAL:
            BINARY(==);
            break;
         case OP_NOTEQUAL:
            BINARY(!=);
            break;
         case OP_LESSEQUAL:
            BINARY(<=);
            break;
         case OP_GREATEREQUAL:
            BINARY(>=);
            break;
         case OP_LESS:
            BINARY(<);
            break;
         case OP_GREATER:
            BINARY(>);
            break;
         case OP_LEFTSHIFT:
            BINARY(<<);
            break;
         case OP_RIGHTSHIFT:
            BINARY(>>);
            break;
         case OP_ADD:
            BINARY(+);
            break;
         case OP_SUBTRACT:
            BINARY(-);
            break;
         case OP_MULTIPLY:
            BINARY(*);
            break;
         case OP_DIVIDE:
            BINARYDIV(/);
            break;
         case OP_MODULUS:
            BINARYDIV(%);
            break;
         case OP_PLUS:
            UNARY(+);
            break;
         case OP_MINUS:
            UNARY(-);
            break;
         case OP_NEGATE:
            UNARY(!);
            break;
         case OP_COMPLEMENT:
            UNARY(~);
            break;
         default:
            assert (0);
      }
   }

   /* Write-back the index skipping the OP_END. */
   *pi = i + 1;

   /* There should be exactly one value left on the stack. This is our result. */
   POP(*result);
   pp_annotate (output, "%d ", *result);
   assert (sp == EXECUTION_STACK_SIZE);
   return GL_TRUE;
}

/*
 * Function execute_expressions() executes up to 2 expressions. The second expression is there
 * for the #line directive which takes 1 or 2 expressions that indicate line and file numbers.
 * If it fails, it returns 0. If it succeeds, it returns the number of executed expressions.
 */

#define EXP_END        0
#define EXP_EXPRESSION 1

static GLuint
execute_expressions (slang_string *output, grammar eid, const byte *expr, GLint results[2],
                     slang_info_log *elog)
{
   GLint success;
   byte *code;
   GLuint size, count = 0;

   success = grammar_fast_check (eid, expr, &code, &size, 64);
   if (success) {
      GLuint i = 0;

      while (code[i++] == EXP_EXPRESSION) {
         assert (count < 2);

         if (!execute_expression (output, code, &i, &results[count], elog)) {
            count = 0;
            break;
         }
         count++;
      }
      grammar_alloc_free (code);
   }
   else {
      slang_info_log_error (elog, "syntax error in preprocessor expression.");\
   }
   return count;
}

/*
 * The pp_symbol structure is used to hold macro definitions and macro formal parameters. The
 * pp_symbols strcture is a collection of pp_symbol. It is used both for storing macro formal
 * parameters and all global macro definitions. Making this unification wastes some memory,
 * becuse macro formal parameters don't need further lists of symbols. We lose 8 bytes per
 * formal parameter here, but making this we can use the same code to substitute macro parameters
 * as well as macros in the source string.
 */

typedef struct
{
   struct pp_symbol_ *symbols;
   GLuint count;
} pp_symbols;

static GLvoid
pp_symbols_init (pp_symbols *self)
{
   self->symbols = NULL;
   self->count = 0;
}

static GLvoid
pp_symbols_free (pp_symbols *);

typedef struct pp_symbol_
{
   slang_string name;
   slang_string replacement;
   pp_symbols parameters;
} pp_symbol;

static GLvoid
pp_symbol_init (pp_symbol *self)
{
   slang_string_init (&self->name);
   slang_string_init (&self->replacement);
   pp_symbols_init (&self->parameters);
}

static GLvoid
pp_symbol_free (pp_symbol *self)
{
   slang_string_free (&self->name);
   slang_string_free (&self->replacement);
   pp_symbols_free (&self->parameters);
}

static GLvoid
pp_symbol_reset (pp_symbol *self)
{
   /* Leave symbol name intact. */
   slang_string_reset (&self->replacement);
   pp_symbols_free (&self->parameters);
   pp_symbols_init (&self->parameters);
}

static GLvoid
pp_symbols_free (pp_symbols *self)
{
   GLuint i;

   for (i = 0; i < self->count; i++)
      pp_symbol_free (&self->symbols[i]);
   _mesa_free (self->symbols);
}

static pp_symbol *
pp_symbols_push (pp_symbols *self)
{
   self->symbols = (pp_symbol *) (_mesa_realloc (self->symbols, self->count * sizeof (pp_symbol),
                                                 (self->count + 1) * sizeof (pp_symbol)));
   if (self->symbols == NULL)
      return NULL;
   pp_symbol_init (&self->symbols[self->count]);