path: root/src/mesa/shader/slang/slang_link.c

/*
 * Mesa 3-D graphics library
 * Version:  6.6
 *
 * Copyright (C) 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_link.c
 * slang linker
 * \author Michal Krol
 */

#include "imports.h"
#include "slang_link.h"
#include "slang_analyse.h"

#define TABLE_GROW(PTR,TYPE,N) \
   (PTR = (TYPE *) (slang_alloc_realloc (PTR, N * sizeof (TYPE), (N + 1) * sizeof (TYPE))))

/*
 * Check if a given name starts with "gl_". Globals with this prefix are
 * treated differently, as they are built-in variables.
 */
static GLboolean
entry_has_gl_prefix (slang_atom name, slang_atom_pool *atoms)
{
   const GLchar *str;

   str = slang_atom_pool_id (atoms, name);
   return str[0] == 'g' && str[1] == 'l' && str[2] == '_';
}

/*
 * slang_active_variables
 */

static GLvoid
slang_active_variables_ctr (slang_active_variables *self)
{
   self->table = NULL;
   self->count = 0;
}

static GLvoid
slang_active_variables_dtr (slang_active_variables *self)
{
   GLuint i;

   for (i = 0; i < self->count; i++)
      slang_alloc_free (self->table[i].name);
   slang_alloc_free (self->table);
}

/*
 * Active variable queried by the application cannot be a structure. Queriable globals
 * (uniforms and attributes) are decomposited into "simple" variables if they are
 * "complex".
 */

static GLboolean
add_simple_variable (slang_active_variables *self, slang_export_data_quant *q, const GLchar *name)
{
   GLuint n;
   slang_active_variable *var;

   n = self->count;
   if (!TABLE_GROW(self->table, slang_active_variable, n))
      return GL_FALSE;

   /* Initialize the new element. Increment table size only when it is fully initilized. */
   var = &self->table[n];
   var->quant = q;
   var->name = slang_string_duplicate (name);
   if (var->name == NULL)
      return GL_FALSE;
   self->count++;

   return GL_TRUE;
}

static GLboolean
add_complex_variable (slang_active_variables *self, slang_export_data_quant *q, GLchar *name,
                      slang_atom_pool *atoms)
{
   slang_string_concat (name, slang_atom_pool_id (atoms, q->name));

   /* If array, add only first element. */
   if (slang_export_data_quant_array (q))
      slang_string_concat (name, "[0]");

   if (slang_export_data_quant_struct (q)) {
      GLuint field_pos, fields, i;

      slang_string_concat (name, ".");
      field_pos = slang_string_length (name);

      /* Break it down into individual fields. */
      fields = slang_export_data_quant_fields (q);
      for (i = 0; i < fields; i++) {
         if (!add_complex_variable (self, &q->structure[i], name, atoms))
            return GL_FALSE;
         name[field_pos] = '\0';
      }

      return GL_TRUE;
   }

   return add_simple_variable (self, q, name);
}

/*
 * Search a list of global variables with a given access (either attribute or uniform)
 * and add it to the list of active variables.
 */
static GLboolean
gather_active_variables (slang_active_variables *self, slang_export_data_table *tbl,
                         slang_export_data_access access)
{
   GLuint i;

   for (i = 0; i < tbl->count; i++) {
      if (tbl->entries[i].access == access) {
         GLchar name[1024] = "";

         if (!add_complex_variable (self, &tbl->entries[i].quant, name, tbl->atoms))
            return GL_FALSE;
      }
   }

   return GL_TRUE;
}

/*
 * slang_attrib_overrides
 */

static GLvoid
slang_attrib_overrides_ctr (slang_attrib_overrides *self)
{
   self->table = NULL;
   self->count = 0;
}

static GLvoid
slang_attrib_overrides_dtr (slang_attrib_overrides *self)
{
   GLuint i;

   for (i = 0; i < self->count; i++)
      slang_alloc_free (self->table[i].name);
   slang_alloc_free (self->table);
}

static slang_attrib_override *
lookup_attrib_override (slang_attrib_overrides *self, const GLchar *name)
{
   GLuint n, i;

   n = self->count;
   for (i = 0; i < n; i++) {
      if (slang_string_compare (name, self->table[i].name) == 0)
         return &self->table[i];
   }
   return NULL;
}

GLboolean
_slang_attrib_overrides_add (slang_attrib_overrides *self, GLuint index, const GLchar *name)
{
   slang_attrib_override *ovr;
   GLuint n;

   /* Attribs can be overriden multiple times. Look-up the table and replace
    * its index if it is found. */
   ovr = lookup_attrib_override (self, name);
   if (ovr != NULL) {
      ovr->index = index;
      return GL_TRUE;
   }

   n = self->count;
   if (!TABLE_GROW(self->table, slang_attrib_override, n))
      return GL_FALSE;

   /* Initialize the new element. Increment table size only when it is fully initilized. */
   ovr = &self->table[n];
   ovr->index = index;
   ovr->name = slang_string_duplicate (name);
   if (ovr->name == NULL)
      return GL_FALSE;
   self->count++;

   return GL_TRUE;
}

/*
 * slang_uniform_bindings
 */

static GLvoid
slang_uniform_bindings_ctr (slang_uniform_bindings *self)
{
   self->table = NULL;
   self->count = 0;
}

static GLvoid
slang_uniform_bindings_dtr (slang_uniform_bindings *self)
{
   GLuint i;

   for (i = 0; i < self->count; i++)
      slang_alloc_free (self->table[i].name);
   slang_alloc_free (self->table);
}

static GLboolean
add_simple_uniform_binding (slang_uniform_bindings *self, slang_export_data_quant *q,
                            const GLchar *name, GLuint index, GLuint addr)
{
   GLuint n, i;
   slang_uniform_binding *bind;

   /* Uniform binding table is shared between vertex and fragment shaders. If the same uniform
    * is declared both in a vertex and fragment shader, only one uniform entry is maintained.
    * When add a uniform binding there can be an entry already allocated for it by the other
    * shader. */
   n = self->count;
   for (i = 0; i < n; i++) {
      if (slang_string_compare (self->table[i].name, name) == 0) {
         self->table[i].address[index] = addr;
         return GL_TRUE;
      }
   }

   if (!TABLE_GROW(self->table, slang_uniform_binding, n))
      return GL_FALSE;

   /* Initialize the new element. Increment table size only when it is fully initilized. */
   bind = &self->table[n];
   bind->quant = q;
   bind->name = slang_string_duplicate (name);
   if (bind->name == NULL)
      return GL_FALSE;
   for (i = 0; i < SLANG_SHADER_MAX; i++)
      bind->address[i] = ~0;
   bind->address[index] = addr;
   self->count++;

   return GL_TRUE;
}

static GLboolean
add_complex_uniform_binding (slang_uniform_bindings *self, slang_export_data_quant *q,
                             GLchar *name, slang_atom_pool *atoms, GLuint index, GLuint addr)
{
   GLuint count, i;

   slang_string_concat (name, slang_atom_pool_id (atoms, q->name));
   count = slang_export_data_quant_elements (q);

   /* If array, add binding for every array element. */
   for (i = 0; i < count; i++) {
      GLuint bracket_pos;

      bracket_pos = slang_string_length (name);
      if (slang_export_data_quant_array (q))
         _mesa_sprintf (&name[slang_string_length (name)], "[%d]", i);

      if (slang_export_data_quant_struct (q)) {
         GLuint field_pos, fields, i;

         slang_string_concat (name, ".");
         field_pos = slang_string_length (name);

         /* Break it down into individual fields. */
         fields = slang_export_data_quant_fields (q);
         for (i = 0; i < fields; i++) {
            if (!add_complex_uniform_binding (self, &q->structure[i], name, atoms, index, addr))
               return GL_FALSE;

            name[field_pos] = '\0';
            addr += slang_export_data_quant_size (&q->structure[i]);
         }
      }
      else {
         if (!add_simple_uniform_binding (self, q, name, index, addr))
            return GL_FALSE;

         addr += slang_export_data_quant_size (q);
      }

      name[bracket_pos] = '\0';
   }

   return GL_TRUE;
}

static GLboolean
gather_uniform_bindings (slang_uniform_bindings *self, slang_export_data_table *tbl, GLuint index)
{
   GLuint n, i;

   n = tbl->count;
   for (i = 0; i < n; i++) {
      if (tbl->entries[i].access == slang_exp_uniform) {
         GLchar name[1024] = "";

         if (!add_complex_uniform_binding (self, &tbl->entries[i].quant, name, tbl->atoms, index,
                                           tbl->entries[i].address))
            return GL_FALSE;
      }
   }

   return GL_TRUE;
}

/*
 * slang_attrib_bindings
 */

static GLvoid
slang_attrib_bindings_ctr (slang_attrib_bindings *self)
{
   GLuint i;

   self->binding_count = 0;
   for (i = 0; i < MAX_VERTEX_ATTRIBS; i++)
      self->slots[i].addr = ~0;
}

static GLvoid
slang_attrib_bindings_dtr (slang_attrib_bindings *self)
{
   GLuint i;

   for (i = 0; i < self->binding_count; i++)
      slang_alloc_free (self->bindings[i].name);
}

/*
 * NOTE: If conventional vertex attribute gl_Vertex is used, application cannot use
 *       vertex attrib index 0 for binding override. Currently this is not checked.
 *       Anyways, attrib index 0 is not used when not explicitly asked.
 */

static GLuint
can_allocate_attrib_slots (slang_attrib_bindings *self, GLuint index, GLuint count)
{
   GLuint i;

   for (i = 0; i < count; i++) {
      if (self->slots[index + i].addr != ~0)
         break;
   }
   return i;
}

static GLuint
allocate_attrib_slots (slang_attrib_bindings *self, GLuint count)
{
   GLuint i;

   /* Start with attrib index 1. Index 0 will be used when explicitly
    * asked by application binding. */
   for (i = 1; i <= MAX_VERTEX_ATTRIBS - count; i++) {
      GLuint size;

      size = can_allocate_attrib_slots (self, i, count);
      if (size == count)
         return i;

      /* Speed-up the search a bit. */
      i += size;
   }

   return MAX_VERTEX_ATTRIBS;
}

static GLboolean
add_attrib_binding (slang_attrib_bindings *self, slang_export_data_quant *q, const GLchar *name,
                    GLuint addr, GLuint index_override)
{
   GLuint slot_span, slot_fill, slot_index, i;
   slang_attrib_binding *bind;

   assert (slang_export_data_quant_simple (q));

   switch (slang_export_data_quant_type (q)) {
   case GL_FLOAT:
      slot_span = 1;
      slot_fill = 1;
      break;
   case GL_FLOAT_VEC2:
      slot_span = 1;
      slot_fill = 2;
      break;
   case GL_FLOAT_VEC3:
      slot_span = 1;
      slot_fill = 3;
      break;
   case GL_FLOAT_VEC4:
      slot_span = 1;
      slot_fill = 4;
      break;
   case GL_FLOAT_MAT2:
      slot_span = 2;
      slot_fill = 2;
      break;
   case GL_FLOAT_MAT3:
      slot_span = 3;
      slot_fill = 3;
      break;
   case GL_FLOAT_MAT4:
      slot_span = 4;
      slot_fill = 4;
      break;
   default:
      assert (0);
   }

   if (index_override == MAX_VERTEX_ATTRIBS)
      slot_index = allocate_attrib_slots (self, slot_span);
   else if (can_allocate_attrib_slots (self, index_override, slot_span) == slot_span)
      slot_index = index_override;
   else
      slot_index = MAX_VERTEX_ATTRIBS;

   if (slot_index == MAX_VERTEX_ATTRIBS) {
      /* TODO: info log: error: MAX_VERTEX_ATTRIBS exceeded */
      return GL_FALSE;
   }

   /* Initialize the new element. Increment table size only when it is fully initilized. */
   bind = &self->bindings[self->binding_count];
   bind->quant = q;
   bind->name = slang_string_duplicate (name);
   if (bind->name == NULL)
      return GL_FALSE;
   bind->first_slot_index = slot_index;
   self->binding_count++;

   for (i = 0; i < slot_span; i++) {
      slang_attrib_slot *slot;

      slot = &self->slots[bind->first_slot_index + i];
      slot->addr = addr + i * slot_fill * 4;
      slot->fill = slot_fill;
   }

   return GL_TRUE;
}

static GLboolean
gather_attrib_bindings (slang_attrib_bindings *self, slang_export_data_table *tbl,
                        slang_attrib_overrides *ovr)
{
   GLuint i;

   /* First pass. Gather attribs that have overriden index slots. */
   for (i = 0; i < tbl->count; i++) {
      if (tbl->entries[i].access == slang_exp_attribute &&
          !entry_has_gl_prefix (tbl->entries[i].quant.name, tbl->atoms)) {
         slang_export_data_quant *quant;
         const GLchar *id;
         slang_attrib_override *ao;

         quant = &tbl->entries[i].quant;
         id = slang_atom_pool_id (tbl->atoms, quant->name);
         ao = lookup_attrib_override (ovr, id);
         if (ao != NULL) {
            if (!add_attrib_binding (self, quant, id, tbl->entries[i].address, ao->index))
               return GL_FALSE;
         }
      }
   }

   /* Second pass. Gather attribs that have not overriden index slots. */
   for (i = 0; i < tbl->count; i++) {
      if (tbl->entries[i].access == slang_exp_attribute &&
          !entry_has_gl_prefix (tbl->entries[i].quant.name, tbl->atoms)) {
         slang_export_data_quant *quant;
         const GLchar *id;
         slang_attrib_override *ao;

         quant = &tbl->entries[i].quant;
         id = slang_atom_pool_id (tbl->atoms, quant->name);
         ao = lookup_attrib_override (ovr, id);
         if (ao == NULL) {
            if (!add_attrib_binding (self, quant, id, tbl->entries[i].address, ao->index))
               return GL_FALSE;
         }
      }
   }

   return GL_TRUE;
}

/*
 * slang_varying_bindings
 */

static GLvoid
slang_varying_bindings_ctr (slang_varying_bindings *self)
{
   self->binding_count = 0;
   self->slot_count = 0;
}

static GLvoid
slang_varying_bindings_dtr (slang_varying_bindings *self)
{
   GLuint i;

   for (i = 0; i < self->binding_count; i++)
      slang_alloc_free (self->bindings[i].name);
}

static GLvoid
update_varying_slots (slang_varying_slot *slots, GLuint count, GLboolean is_vert, GLuint addr,
                      GLuint do_offset)
{
   GLuint i;

   for (i = 0; i < count; i++) {
      if (is_vert)
         slots[i].vert_addr = addr + i * 4 * do_offset;
      else
         slots[i].frag_addr = addr + i * 4 * do_offset;
   }
}

static GLboolean
add_varying_binding (slang_varying_bindings *self, slang_export_data_quant *q, const GLchar *name,
                     GLboolean is_vert, GLuint addr)
{
   GLuint n, slot_span, i;
   slang_varying_binding *bind;

   n = self->binding_count;
   slot_span = slang_export_data_quant_components (q) * slang_export_data_quant_elements (q);
   for (i = 0; i < n; i++) {
      if (slang_string_compare (self->bindings[i].name, name) == 0) {
         /* TODO: data quantities must match, or else link fails */
         update_varying_slots (&self->slots[self->bindings[i].first_slot_index], slot_span,
                               is_vert, addr, 1);
         return GL_TRUE;
      }
   }

   if (self->slot_count + slot_span > MAX_VARYING * 4) {
      /* TODO: info log: error: MAX_VARYING_FLOATS exceeded */
      return GL_FALSE;
   }

   /* Initialize the new element. Increment table size only when it is fully initilized. */
   bind = &self->bindings[n];
   bind->quant = q;
   bind->name = slang_string_duplicate (name);
   if (bind->name == NULL)
      return GL_FALSE;
   bind->first_slot_index = self->slot_count;
   self->binding_count++;

   update_varying_slots (&self->slots[bind->first_slot_index], slot_span, is_vert, addr, 1);
   update_varying_slots (&self->slots[bind->first_slot_index], slot_span, !is_vert, ~0, 0);
   self->slot_count += slot_span;

   return GL_TRUE;
}

static GLboolean
gather_varying_bindings (slang_varying_bindings *self, slang_export_data_table *tbl,
                         GLboolean is_vert)
{
   GLuint i;

   for (i = 0; i < tbl->count; i++) {
      if (tbl->entries[i].access == slang_exp_varying &&
          !entry_has_gl_prefix (tbl->entries[i].quant.name, tbl->atoms)) {
         if (!add_varying_binding (self, &tbl->entries[i].quant,
                                   slang_atom_pool_id (tbl->atoms, tbl->entries[i].quant.name),
                                   is_vert, tbl->entries[i].address))
            return GL_FALSE;
      }
   }

   return GL_TRUE;
}

/*
 * slang_texture_bindings
 */

GLvoid
_slang_texture_usages_ctr (slang_texture_usages *self)
{
   self->table = NULL;
   self->count = 0;
}

GLvoid
_slang_texture_usages_dtr (slang_texture_usages *self)
{
   slang_alloc_free (self->table);
}

/*
 * slang_program
 */

GLvoid
_slang_program_ctr (slang_program *self)
{
   GLuint i;

   slang_active_variables_ctr (&self->active_uniforms);
   slang_active_variables_ctr (&self->active_attribs);
   slang_attrib_overrides_ctr (&self->attrib_overrides);
   slang_uniform_bindings_ctr (&self->uniforms);
   slang_attrib_bindings_ctr (&self->attribs);
   slang_varying_bindings_ctr (&self->varyings);
   _slang_texture_usages_ctr (&self->texture_usage);
   for (i = 0; i < SLANG_SHADER_MAX; i++) {
      GLuint j;

      for (j = 0; j < SLANG_COMMON_FIXED_MAX; j++)
         self->common_fixed_entries[i][j] = ~0;
      for (j = 0; j < SLANG_COMMON_CODE_MAX; j++)
         self->code[i][j] = ~0;
      self->machines[i] = NULL;
      self->assemblies[i] = NULL;
   }
   for (i = 0; i < SLANG_VERTEX_FIXED_MAX; i++)
      self->vertex_fixed_entries[i] = ~0;
   for (i = 0; i < SLANG_FRAGMENT_FIXED_MAX; i++)
      self->fragment_fixed_entries[i] = ~0;
}

GLvoid
_slang_program_dtr (slang_program *self)
{
   slang_active_variables_dtr (&self->active_uniforms);
   slang_active_variables_dtr (&self->active_attribs);
   slang_attrib_overrides_dtr (&self->attrib_overrides);
   slang_uniform_bindings_dtr (&self->uniforms);
   slang_attrib_bindings_dtr (&self->attribs);
   slang_varying_bindings_dtr (&self->varyings);
   _slang_texture_usages_dtr (&self->texture_usage);
}

GLvoid
_slang_program_rst (slang_program *self)
{
   GLuint i;

   slang_active_variables_dtr (&self->active_uniforms);
   slang_active_variables_dtr (&self->active_attribs);
   slang_uniform_bindings_dtr (&self->uniforms);
   slang_attrib_bindings_dtr (&self->attribs);
   slang_varying_bindings_dtr (&self->varyings);
   _slang_texture_usages_dtr (&self->texture_usage);

   slang_active_variables_ctr (&self->active_uniforms);
   slang_active_variables_ctr (&self->active_attribs);
   slang_uniform_bindings_ctr (&self->uniforms);
   slang_attrib_bindings_ctr (&self->attribs);
   slang_varying_bindings_ctr (&self->varyings);
   _slang_texture_usages_ctr (&self->texture_usage);
   for (i = 0; i < SLANG_SHADER_MAX; i++) {
      GLuint j;

      for (j = 0; j < SLANG_COMMON_FIXED_MAX; j++)
         self->common_fixed_entries[i][j] = ~0;
      for (j = 0; j < SLANG_COMMON_CODE_MAX; j++)
         self->code[i][j] = ~0;
   }
   for (i = 0; i < SLANG_VERTEX_FIXED_MAX; i++)
      self->vertex_fixed_entries[i] = ~0;
   for (i = 0; i < SLANG_FRAGMENT_FIXED_MAX; i++)
      self->fragment_fixed_entries[i] = ~0;
}

/*
 * _slang_link()
 */

static GLuint
gd (slang_export_data_table *tbl, const GLchar *name)
{
   slang_atom atom;
   GLuint i;

   atom = slang_atom_pool_atom (tbl->atoms, name);
   if (atom == SLANG_ATOM_NULL)
      return ~0;

   for (i = 0; i < tbl->count; i++) {
      if (atom == tbl->entries[i].quant.name)
         return tbl->entries[i].address;
   }
   return ~0;
}

static GLvoid
resolve_common_fixed (GLuint e[], slang_export_data_table *tbl)
{
   e[SLANG_COMMON_FIXED_MODELVIEWMATRIX] = gd (tbl, "gl_ModelViewMatrix");
   e[SLANG_COMMON_FIXED_PROJECTIONMATRIX] = gd (tbl, "gl_ProjectionMatrix");
   e[SLANG_COMMON_FIXED_MODELVIEWPROJECTIONMATRIX] = gd (tbl, "gl_ModelViewProjectionMatrix");
   e[SLANG_COMMON_FIXED_TEXTUREMATRIX] = gd (tbl, "gl_TextureMatrix");
   e[SLANG_COMMON_FIXED_NORMALMATRIX] = gd (tbl, "gl_NormalMatrix");
   e[SLANG_COMMON_FIXED_MODELVIEWMATRIXINVERSE] = gd (tbl, "gl_ModelViewMatrixInverse");
   e[SLANG_COMMON_FIXED_PROJECTIONMATRIXINVERSE] = gd (tbl, "gl_ProjectionMatrixInverse");
   e[SLANG_COMMON_FIXED_MODELVIEWPROJECTIONMATRIXINVERSE] = gd (tbl, "gl_ModelViewProjectionMatrixInverse");
   e[SLANG_COMMON_FIXED_TEXTUREMATRIXINVERSE] = gd (tbl, "gl_TextureMatrixInverse");
   e[SLANG_COMMON_FIXED_MODELVIEWMATRIXTRANSPOSE] = gd (tbl, "gl_ModelViewMatrixTranspose");
   e[SLANG_COMMON_FIXED_PROJECTIONMATRIXTRANSPOSE] = gd (tbl, "gl_ProjectionMatrixTranspose");
   e[SLANG_COMMON_FIXED_MODELVIEWPROJECTIONMATRIXTRANSPOSE] = gd (tbl, "gl_ModelViewProjectionMatrixTranspose");
   e[SLANG_COMMON_FIXED_TEXTUREMATRIXTRANSPOSE] = gd (tbl, "gl_TextureMatrixTranspose");
   e[SLANG_COMMON_FIXED_MODELVIEWMATRIXINVERSETRANSPOSE] = gd (tbl, "gl_ModelViewMatrixInverseTranspose");
   e[SLANG_COMMON_FIXED_PROJECTIONMATRIXINVERSETRANSPOSE] = gd (tbl, "gl_ProjectionMatrixInverseTranspose");
   e[SLANG_COMMON_FIXED_MODELVIEWPROJECTIONMATRIXINVERSETRANSPOSE] = gd (tbl, "gl_ModelViewProjectionMatrixInverseTranspose");
   e[SLANG_COMMON_FIXED_TEXTUREMATRIXINVERSETRANSPOSE] = gd (tbl, "gl_TextureMatrixInverseTranspose");
   e[SLANG_COMMON_FIXED_NORMALSCALE] = gd (tbl, "gl_NormalScale");
   e[SLANG_COMMON_FIXED_DEPTHRANGE] = gd (tbl, "gl_DepthRange");
   e[SLANG_COMMON_FIXED_CLIPPLANE] = gd (tbl, "gl_ClipPlane");
   e[SLANG_COMMON_FIXED_POINT] = gd (tbl, "gl_Point");
   e[SLANG_COMMON_FIXED_FRONTMATERIAL] = gd (tbl, "gl_FrontMaterial");
   e[SLANG_COMMON_FIXED_BACKMATERIAL] = gd (tbl, "gl_BackMaterial");
   e[SLANG_COMMON_FIXED_LIGHTSOURCE] = gd (tbl, "gl_LightSource");
   e[SLANG_COMMON_FIXED_LIGHTMODEL] = gd (tbl, "gl_LightModel");
   e[SLANG_COMMON_FIXED_FRONTLIGHTMODELPRODUCT] = gd (tbl, "gl_FrontLightModelProduct");
   e[SLANG_COMMON_FIXED_BACKLIGHTMODELPRODUCT] = gd (tbl, "gl_BackLightModelProduct");
   e[SLANG_COMMON_FIXED_FRONTLIGHTPRODUCT] = gd (tbl, "gl_FrontLightProduct");
   e[SLANG_COMMON_FIXED_BACKLIGHTPRODUCT] = gd (tbl, "gl_BackLightProduct");
   e[SLANG_COMMON_FIXED_TEXTUREENVCOLOR] = gd (tbl, "gl_TextureEnvColor");
   e[SLANG_COMMON_FIXED_EYEPLANES] = gd (tbl, "gl_EyePlaneS");
   e[SLANG_COMMON_FIXED_EYEPLANET] = gd (tbl, "gl_EyePlaneT");
   e[SLANG_COMMON_FIXED_EYEPLANER] = gd (tbl, "gl_EyePlaneR");
   e[SLANG_COMMON_FIXED_EYEPLANEQ] = gd (tbl, "gl_EyePlaneQ");
   e[SLANG_COMMON_FIXED_OBJECTPLANES] = gd (tbl, "gl_ObjectPlaneS");
   e[SLANG_COMMON_FIXED_OBJECTPLANET] = gd (tbl, "gl_ObjectPlaneT");
   e[SLANG_COMMON_FIXED_OBJECTPLANER] = gd (tbl, "gl_ObjectPlaneR");
   e[SLANG_COMMON_FIXED_OBJECTPLANEQ] = gd (tbl, "gl_ObjectPlaneQ");
   e[SLANG_COMMON_FIXED_FOG] = gd (tbl, "gl_Fog");
}

static GLvoid
resolve_vertex_fixed (GLuint e[], slang_export_data_table *tbl)
{
   e[SLANG_VERTEX_FIXED_POSITION] = gd (tbl, "gl_Position");
   e[SLANG_VERTEX_FIXED_POINTSIZE] = gd (tbl,  "gl_PointSize");
   e[SLANG_VERTEX_FIXED_CLIPVERTEX] = gd (tbl, "gl_ClipVertex");
   e[SLANG_VERTEX_FIXED_COLOR] = gd (tbl, "gl_Color");
   e[SLANG_VERTEX_FIXED_SECONDARYCOLOR] = gd (tbl, "gl_SecondaryColor");
   e[SLANG_VERTEX_FIXED_NORMAL] = gd (tbl, "gl_Normal");
   e[SLANG_VERTEX_FIXED_VERTEX] = gd (tbl, "gl_Vertex");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD0] = gd (tbl, "gl_MultiTexCoord0");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD1] = gd (tbl, "gl_MultiTexCoord1");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD2] = gd (tbl, "gl_MultiTexCoord2");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD3] = gd (tbl, "gl_MultiTexCoord3");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD4] = gd (tbl, "gl_MultiTexCoord4");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD5] = gd (tbl, "gl_MultiTexCoord5");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD6] = gd (tbl, "gl_MultiTexCoord6");
   e[SLANG_VERTEX_FIXED_MULTITEXCOORD7] = gd (tbl, "gl_MultiTexCoord7");
   e[SLANG_VERTEX_FIXED_FOGCOORD] = gd (tbl, "gl_FogCoord");
   e[SLANG_VERTEX_FIXED_FRONTCOLOR] = gd (tbl, "gl_FrontColor");
   e[SLANG_VERTEX_FIXED_BACKCOLOR] = gd (tbl, "gl_BackColor");
   e[SLANG_VERTEX_FIXED_FRONTSECONDARYCOLOR] = gd (tbl, "gl_FrontSecondaryColor");
   e[SLANG_VERTEX_FIXED_BACKSECONDARYCOLOR] = gd (tbl, "gl_BackSecondaryColor");
   e[SLANG_VERTEX_FIXED_TEXCOORD] = gd (tbl, "gl_TexCoord");
   e[SLANG_VERTEX_FIXED_FOGFRAGCOORD] = gd (tbl, "gl_FogFragCoord");
}

static GLvoid
resolve_fragment_fixed (GLuint e[], slang_export_data_table *tbl)
{
   e[SLANG_FRAGMENT_FIXED_FRAGCOORD] = gd (tbl, "gl_FragCoord");
   e[SLANG_FRAGMENT_FIXED_FRONTFACING] = gd (tbl, "gl_FrontFacing");
   e[SLANG_FRAGMENT_FIXED_FRAGCOLOR] = gd (tbl, "gl_FragColor");
   e[SLANG_FRAGMENT_FIXED_FRAGDATA] = gd (tbl, "gl_FragData");
   e[SLANG_FRAGMENT_FIXED_FRAGDEPTH] = gd (tbl, "gl_FragDepth");
   e[SLANG_FRAGMENT_FIXED_COLOR] = gd (tbl, "gl_Color");
   e[SLANG_FRAGMENT_FIXED_SECONDARYCOLOR] = gd (tbl, "gl_SecondaryColor");
   e[SLANG_FRAGMENT_FIXED_TEXCOORD] = gd (tbl, "gl_TexCoord");
   e[SLANG_FRAGMENT_FIXED_FOGFRAGCOORD] = gd (tbl, "gl_FogFragCoord");
}

static GLuint
gc (slang_export_code_table *tbl, const GLchar *name)
{
   slang_atom atom;
   GLuint i;

   atom = slang_atom_pool_atom (tbl->atoms, name);
   if (atom == SLANG_ATOM_NULL)
      return ~0;

   for (i = 0; i < tbl->count; i++) {
      if (atom == tbl->entries[i].name)
         return tbl->entries[i].address;
   }
   return ~0;
}

static GLvoid
resolve_common_code (GLuint code[], slang_export_code_table *tbl)
{
   code[SLANG_COMMON_CODE_MAIN] = gc (tbl, "@main");
}

GLboolean
_slang_link (slang_program *prog, slang_code_object **objects, GLuint count)
{
   GLuint i;

   for (i = 0; i < count; i++) {
      GLuint index;

      if (objects[i]->unit.type == slang_unit_fragment_shader) {
         index = SLANG_SHADER_FRAGMENT;
         resolve_fragment_fixed (prog->fragment_fixed_entries, &objects[i]->expdata);
      }
      else {
         index = SLANG_SHADER_VERTEX;
         resolve_vertex_fixed (prog->vertex_fixed_entries, &objects[i]->expdata);
         if (!gather_attrib_bindings (&prog->attribs, &objects[i]->expdata,
                                      &prog->attrib_overrides))
            return GL_FALSE;
      }

      if (!gather_active_variables (&prog->active_uniforms, &objects[i]->expdata, slang_exp_uniform))
         return GL_FALSE;
      if (!gather_active_variables (&prog->active_attribs, &objects[i]->expdata, slang_exp_attribute))
         return GL_FALSE;
      if (!gather_uniform_bindings (&prog->uniforms, &objects[i]->expdata, index))
         return GL_FALSE;
      if (!gather_varying_bindings (&prog->varyings, &objects[i]->expdata,
                                    index == SLANG_SHADER_VERTEX))
         return GL_FALSE;
      resolve_common_fixed (prog->common_fixed_entries[index], &objects[i]->expdata);
      resolve_common_code (prog->code[index], &objects[i]->expcode);
      prog->machines[index] = &objects[i]->machine;
      prog->assemblies[index] = &objects[i]->assembly;
   }

   /* TODO: all varyings read by fragment shader must be written by vertex shader */

   if (!_slang_analyse_texture_usage (prog))
      return GL_FALSE;

   return GL_TRUE;
}