/**
 * Update fragment state.  This is called just prior to drawing
 * something when some fragment-related state has changed.
 */
void 
llvmpipe_update_fs(struct llvmpipe_context *lp)
{
   struct lp_fragment_shader *shader = lp->fs;
   struct lp_fragment_shader_variant_key key;
   struct lp_fragment_shader_variant *variant = NULL;
   struct lp_fs_variant_list_item *li;

   make_variant_key(lp, shader, &key);

   li = first_elem(&shader->variants);
   while(!at_end(&shader->variants, li)) {
      if(memcmp(&li->base->key, &key, shader->variant_key_size) == 0) {
         variant = li->base;
         break;
      }
      li = next_elem(li);
   }

   if (variant) {
      move_to_head(&lp->fs_variants_list, &variant->list_item_global);
   }
   else {
      int64_t t0, t1;
      int64_t dt;
      unsigned i;
      if (lp->nr_fs_variants >= LP_MAX_SHADER_VARIANTS) {
         struct pipe_context *pipe = &lp->pipe;

         /*
          * XXX: we need to flush the context until we have some sort of reference
          * counting in fragment shaders as they may still be binned
          * Flushing alone might not be sufficient we need to wait on it too.
          */
         llvmpipe_finish(pipe, __FUNCTION__);

         for (i = 0; i < LP_MAX_SHADER_VARIANTS / 4; i++) {
            struct lp_fs_variant_list_item *item = last_elem(&lp->fs_variants_list);
            remove_shader_variant(lp, item->base);
         }
      }
      t0 = os_time_get();

      variant = generate_variant(lp, shader, &key);

      t1 = os_time_get();
      dt = t1 - t0;
      LP_COUNT_ADD(llvm_compile_time, dt);
      LP_COUNT_ADD(nr_llvm_compiles, 2);  /* emit vs. omit in/out test */

      if (variant) {
         insert_at_head(&shader->variants, &variant->list_item_local);
         insert_at_head(&lp->fs_variants_list, &variant->list_item_global);
         lp->nr_fs_variants++;
         shader->variants_cached++;
      }
   }

   lp_setup_set_fs_variant(lp->setup, variant);
}
static void
llvm_middle_end_prepare_gs(struct llvm_middle_end *fpme)
{
   struct draw_context *draw = fpme->draw;
   struct draw_geometry_shader *gs = draw->gs.geometry_shader;
   struct draw_gs_llvm_variant_key *key;
   struct draw_gs_llvm_variant *variant = NULL;
   struct draw_gs_llvm_variant_list_item *li;
   struct llvm_geometry_shader *shader = llvm_geometry_shader(gs);
   char store[DRAW_GS_LLVM_MAX_VARIANT_KEY_SIZE];
   unsigned i;

   key = draw_gs_llvm_make_variant_key(fpme->llvm, store);

   /* Search shader's list of variants for the key */
   li = first_elem(&shader->variants);
   while (!at_end(&shader->variants, li)) {
      if (memcmp(&li->base->key, key, shader->variant_key_size) == 0) {
         variant = li->base;
         break;
      }
      li = next_elem(li);
   }

   if (variant) {
      /* found the variant, move to head of global list (for LRU) */
      move_to_head(&fpme->llvm->gs_variants_list,
                   &variant->list_item_global);
   }
   else {
      /* Need to create new variant */

      /* First check if we've created too many variants.  If so, free
       * 25% of the LRU to avoid using too much memory.
       */
      if (fpme->llvm->nr_gs_variants >= DRAW_MAX_SHADER_VARIANTS) {
         /*
          * XXX: should we flush here ?
          */
         for (i = 0; i < DRAW_MAX_SHADER_VARIANTS / 4; i++) {
            struct draw_gs_llvm_variant_list_item *item;
            if (is_empty_list(&fpme->llvm->gs_variants_list)) {
               break;
            }
            item = last_elem(&fpme->llvm->gs_variants_list);
            assert(item);
            assert(item->base);
            draw_gs_llvm_destroy_variant(item->base);
         }
      }

      variant = draw_gs_llvm_create_variant(fpme->llvm, gs->info.num_outputs, key);

      if (variant) {
         insert_at_head(&shader->variants, &variant->list_item_local);
         insert_at_head(&fpme->llvm->gs_variants_list,
                        &variant->list_item_global);
         fpme->llvm->nr_gs_variants++;
         shader->variants_cached++;
      }
   }

   gs->current_variant = variant;
}
/**
 * Prepare/validate middle part of the vertex pipeline.
 * NOTE: if you change this function, also look at the non-LLVM
 * function fetch_pipeline_prepare() for similar changes.
 */
static void
llvm_middle_end_prepare( struct draw_pt_middle_end *middle,
                         unsigned in_prim,
                         unsigned opt,
                         unsigned *max_vertices )
{
   struct llvm_middle_end *fpme = llvm_middle_end(middle);
   struct draw_context *draw = fpme->draw;
   struct draw_vertex_shader *vs = draw->vs.vertex_shader;
   struct draw_geometry_shader *gs = draw->gs.geometry_shader;
   const unsigned out_prim = gs ? gs->output_primitive :
      u_assembled_prim(in_prim);
   unsigned point_clip = draw->rasterizer->fill_front == PIPE_POLYGON_MODE_POINT ||
                         out_prim == PIPE_PRIM_POINTS;
   unsigned nr;

   fpme->input_prim = in_prim;
   fpme->opt = opt;

   draw_pt_post_vs_prepare( fpme->post_vs,
                            draw->clip_xy,
                            draw->clip_z,
                            draw->clip_user,
                            point_clip ? draw->guard_band_points_xy :
                                         draw->guard_band_xy,
                            draw->identity_viewport,
                            draw->rasterizer->clip_halfz,
                            (draw->vs.edgeflag_output ? TRUE : FALSE) );

   draw_pt_so_emit_prepare( fpme->so_emit, gs == NULL );

   if (!(opt & PT_PIPELINE)) {
      draw_pt_emit_prepare( fpme->emit,
			    out_prim,
                            max_vertices );

      *max_vertices = MAX2( *max_vertices, 4096 );
   }
   else {
      /* limit max fetches by limiting max_vertices */
      *max_vertices = 4096;
   }

   /* Get the number of float[4] attributes per vertex.
    * Note: this must be done after draw_pt_emit_prepare() since that
    * can effect the vertex size.
    */
   nr = MAX2(vs->info.num_inputs, draw_total_vs_outputs(draw));

   /* Always leave room for the vertex header whether we need it or
    * not.  It's hard to get rid of it in particular because of the
    * viewport code in draw_pt_post_vs.c.
    */
   fpme->vertex_size = sizeof(struct vertex_header) + nr * 4 * sizeof(float);

   /* Get the number of float[4] attributes per vertex.
    * Note: this must be done after draw_pt_emit_prepare() since that
    * can effect the vertex size.
    */
   nr = MAX2(vs->info.num_inputs, draw_total_vs_outputs(draw));

   /* Always leave room for the vertex header whether we need it or
    * not.  It's hard to get rid of it in particular because of the
    * viewport code in draw_pt_post_vs.c.
    */
   fpme->vertex_size = sizeof(struct vertex_header) + nr * 4 * sizeof(float);

   /* return even number */
   *max_vertices = *max_vertices & ~1;

   /* Find/create the vertex shader variant */
   {
      struct draw_llvm_variant_key *key;
      struct draw_llvm_variant *variant = NULL;
      struct draw_llvm_variant_list_item *li;
      struct llvm_vertex_shader *shader = llvm_vertex_shader(vs);
      char store[DRAW_LLVM_MAX_VARIANT_KEY_SIZE];
      unsigned i;

      key = draw_llvm_make_variant_key(fpme->llvm, store);

      /* Search shader's list of variants for the key */
      li = first_elem(&shader->variants);
      while (!at_end(&shader->variants, li)) {
         if (memcmp(&li->base->key, key, shader->variant_key_size) == 0) {
            variant = li->base;
            break;
         }
         li = next_elem(li);
      }

      if (variant) {
         /* found the variant, move to head of global list (for LRU) */
         move_to_head(&fpme->llvm->vs_variants_list,
                      &variant->list_item_global);
      }
      else {
         /* Need to create new variant */

         /* First check if we've created too many variants.  If so, free
          * 25% of the LRU to avoid using too much memory.
          */
         if (fpme->llvm->nr_variants >= DRAW_MAX_SHADER_VARIANTS) {
            /*
             * XXX: should we flush here ?
             */
            for (i = 0; i < DRAW_MAX_SHADER_VARIANTS / 4; i++) {
               struct draw_llvm_variant_list_item *item;
               if (is_empty_list(&fpme->llvm->vs_variants_list)) {
                  break;
               }
               item = last_elem(&fpme->llvm->vs_variants_list);
               assert(item);
               assert(item->base);
               draw_llvm_destroy_variant(item->base);
            }
         }

         variant = draw_llvm_create_variant(fpme->llvm, nr, key);

         if (variant) {
            insert_at_head(&shader->variants, &variant->list_item_local);
            insert_at_head(&fpme->llvm->vs_variants_list,
                           &variant->list_item_global);
            fpme->llvm->nr_variants++;
            shader->variants_cached++;
         }
      }

      fpme->current_variant = variant;
   }

   if (gs) {
      llvm_middle_end_prepare_gs(fpme);
   }
}
static void
llvm_middle_end_prepare( struct draw_pt_middle_end *middle,
                         unsigned in_prim,
                         unsigned opt,
                         unsigned *max_vertices )
{
    struct llvm_middle_end *fpme = (struct llvm_middle_end *)middle;
    struct draw_context *draw = fpme->draw;
    struct llvm_vertex_shader *shader =
        llvm_vertex_shader(draw->vs.vertex_shader);
    char store[DRAW_LLVM_MAX_VARIANT_KEY_SIZE];
    struct draw_llvm_variant_key *key;
    struct draw_llvm_variant *variant = NULL;
    struct draw_llvm_variant_list_item *li;
    unsigned i;
    unsigned instance_id_index = ~0;
    const unsigned out_prim = (draw->gs.geometry_shader ?
                               draw->gs.geometry_shader->output_primitive :
                               in_prim);

    /* Add one to num_outputs because the pipeline occasionally tags on
     * an additional texcoord, eg for AA lines.
     */
    const unsigned nr = MAX2( shader->base.info.num_inputs,
                              shader->base.info.num_outputs + 1 );

    /* Scan for instanceID system value.
     * XXX but we never use instance_id_index?!
     */
    for (i = 0; i < shader->base.info.num_inputs; i++) {
        if (shader->base.info.input_semantic_name[i] == TGSI_SEMANTIC_INSTANCEID) {
            instance_id_index = i;
            break;
        }
    }

    fpme->input_prim = in_prim;
    fpme->opt = opt;

    /* Always leave room for the vertex header whether we need it or
     * not.  It's hard to get rid of it in particular because of the
     * viewport code in draw_pt_post_vs.c.
     */
    fpme->vertex_size = sizeof(struct vertex_header) + nr * 4 * sizeof(float);


    /* XXX: it's not really gl rasterization rules we care about here,
     * but gl vs dx9 clip spaces.
     */
    draw_pt_post_vs_prepare( fpme->post_vs,
                             draw->clip_xy,
                             draw->clip_z,
                             draw->clip_user,
                             draw->identity_viewport,
                             (boolean)draw->rasterizer->gl_rasterization_rules,
                             (draw->vs.edgeflag_output ? TRUE : FALSE) );

    draw_pt_so_emit_prepare( fpme->so_emit );

    if (!(opt & PT_PIPELINE)) {
        draw_pt_emit_prepare( fpme->emit,
                              out_prim,
                              max_vertices );

        *max_vertices = MAX2( *max_vertices, 4096 );
    }
    else {
        /* limit max fetches by limiting max_vertices */
        *max_vertices = 4096;
    }

    /* return even number */
    *max_vertices = *max_vertices & ~1;

    key = draw_llvm_make_variant_key(fpme->llvm, store);

    /* Search shader's list of variants for the key */
    li = first_elem(&shader->variants);
    while (!at_end(&shader->variants, li)) {
        if (memcmp(&li->base->key, key, shader->variant_key_size) == 0) {
            variant = li->base;
            break;
        }
        li = next_elem(li);
    }

    if (variant) {
        /* found the variant, move to head of global list (for LRU) */
        move_to_head(&fpme->llvm->vs_variants_list, &variant->list_item_global);
    }
    else {
        /* Need to create new variant */
        unsigned i;

        /* First check if we've created too many variants.  If so, free
         * 25% of the LRU to avoid using too much memory.
         */
        if (fpme->llvm->nr_variants >= DRAW_MAX_SHADER_VARIANTS) {
            /*
             * XXX: should we flush here ?
             */
            for (i = 0; i < DRAW_MAX_SHADER_VARIANTS / 4; i++) {
                struct draw_llvm_variant_list_item *item =
                    last_elem(&fpme->llvm->vs_variants_list);
                draw_llvm_destroy_variant(item->base);
            }
        }

        variant = draw_llvm_create_variant(fpme->llvm, nr, key);

        if (variant) {
            insert_at_head(&shader->variants, &variant->list_item_local);
            insert_at_head(&fpme->llvm->vs_variants_list, &variant->list_item_global);
            fpme->llvm->nr_variants++;
            shader->variants_cached++;
        }
    }

    fpme->current_variant = variant;

    /*XXX we only support one constant buffer */
    fpme->llvm->jit_context.vs_constants =
        draw->pt.user.vs_constants[0];
    fpme->llvm->jit_context.gs_constants =
        draw->pt.user.gs_constants[0];
    fpme->llvm->jit_context.planes =
        (float (*) [12][4]) draw->pt.user.planes[0];
    fpme->llvm->jit_context.viewport =
        (float *)draw->viewport.scale;

}