path: root/src/imagination/vulkan/pvr_hw_pass.c

/*
 * Copyright © 2022 Imagination Technologies Ltd.
 *
 * 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 (including the next
 * paragraph) 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 THE
 * AUTHORS OR COPYRIGHT HOLDERS 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.
 */

#include <assert.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include <vulkan/vulkan.h>

#include "hwdef/rogue_hw_defs.h"
#include "hwdef/rogue_hw_utils.h"
#include "pvr_hw_pass.h"
#include "pvr_private.h"
#include "util/bitset.h"
#include "util/list.h"
#include "util/macros.h"
#include "util/u_math.h"
#include "vk_alloc.h"
#include "vk_format.h"
#include "vk_log.h"

struct pvr_render_int_subpass {
   /* Points to the input subpass. This is set to NULL when the subpass is
    * unscheduled.
    */
   struct pvr_render_subpass *subpass;

   /* Count of other subpasses which have this subpass as a dependency. */
   uint32_t out_subpass_count;

   /* Pointers to the other subpasses which have this subpass as a dependency.
    */
   struct pvr_render_int_subpass **out_subpasses;

   /* Count of subpasses on which this subpass is dependent and which haven't
    * been scheduled yet.
    */
   uint32_t in_subpass_count;
};

struct pvr_renderpass_resource {
   /* Resource type allocated for render target. */
   enum usc_mrt_resource_type type;

   union {
      /* If type == USC_MRT_RESOURCE_TYPE_OUTPUT_REG. */
      struct {
         /* The output register to use. */
         uint32_t output_reg;

         /* The offset in bytes within the output register. */
         uint32_t offset;
      } reg;

      /* If type == USC_MRT_RESOURCE_TYPE_MEMORY.  */
      struct {
         /* The index of the tile buffer to use. */
         uint32_t tile_buffer;

         /* The offset (in dwords) within the tile buffer. */
         uint32_t offset_dw;
      } mem;
   };
};

struct pvr_render_int_attachment {
   /* Points to the corresponding input attachment. */
   struct pvr_render_pass_attachment *attachment;

   /* True if this attachment is referenced in the currently open render. */
   bool is_used;

   /* Operation to use when this attachment is non-resident and referenced as a
    * color or depth attachment.
    */
   VkAttachmentLoadOp load_op;

   /* Operation to use for the stencil component when this attachment is
    * non-resident and referenced as a color or depth attachment.
    */
   VkAttachmentLoadOp stencil_load_op;

   /* Count of uses of this attachment in unscheduled subpasses. */
   uint32_t remaining_count;

   /* Count of uses of the stencil component of this attachment in unscheduled
    * subpasses.
    */
   uint32_t stencil_remaining_count;

   /* If this attachment has currently allocated on-chip storage then details of
    * the allocated location.
    */
   struct usc_mrt_resource resource;

   /* Index of the subpass in the current render where the attachment is first
    * used. VK_ATTACHMENT_UNUSED if the attachment isn't used in the current
    * render.
    */
   int32_t first_use;

   /* Index of the subpass in the current render where the attachment is last
    * used.
    */
   int32_t last_use;

   /* Index of the subpass (global) where the attachment is last read. */
   int32_t last_read;

   /* If this attachment has currently allocated on-chip storage then the entry
    * in context.active_surf_list.
    */
   struct list_head link;

   /* During pvr_close_render: if this attachment has allocated on-chip storage
    * then the index in pvr_renderpass_hwsetup_render.eot_setup.mrt_resources
    * with details of the storage location. Otherwise -1.
    */
   int32_t mrt_idx;

   /* Index of the last render where the attachment was the source of an MSAA
    * resolve.
    */
   int32_t last_resolve_src_render;

   /* Index of the last render where the attachment was the destination of an
    * MSAA resolve.
    */
   int32_t last_resolve_dst_render;

   /* true if the attachment is used with a z replicate in the current render.
    */
   bool z_replicate;

   /* true if this attachment can be resolved by the PBE. */
   bool is_pbe_downscalable;

   /* true if this attachment requires an EOT attachment. */
   bool eot_surf_required;
};

/* Which parts of the output registers/a tile buffer are currently allocated. */
struct pvr_renderpass_alloc_buffer {
   /* Bit array. A bit is set if the corresponding dword is allocated. */
   BITSET_DECLARE(allocs, 8U);
};

struct pvr_renderpass_alloc {
   /* Which pixel output registers are allocated. */
   struct pvr_renderpass_alloc_buffer output_reg;

   /* Range of allocated output registers. */
   uint32_t output_regs_count;

   /* Number of tile buffers allocated. */
   uint32_t tile_buffers_count;

   /* Which parts of each tile buffer are allocated. Length is
    * tile_buffers_count.
    */
   struct pvr_renderpass_alloc_buffer *tile_buffers;
};

struct pvr_renderpass_subpass {
   /* A pointer to the input subpass description. */
   struct pvr_render_subpass *input_subpass;

   /* true if the depth attachment for this subpass has z replication enabled.
    */
   bool z_replicate;

   /* Which pixel output registers/tile buffer locations are allocated during
    * this subpass.
    */
   struct pvr_renderpass_alloc alloc;
};

struct pvr_renderpass_context {
   /* Internal information about each input attachment. */
   struct pvr_render_int_attachment *int_attach;

   /* Internal information about each input subpass. */
   struct pvr_render_int_subpass *int_subpasses;

   /* Input structure. */
   struct pvr_render_pass *pass;

   /* Output structure. */
   struct pvr_renderpass_hwsetup *hw_setup;

   /* In-progress render. */
   struct pvr_renderpass_hwsetup_render *hw_render;

   /* Information about each subpass in the current render. */
   struct pvr_renderpass_subpass *subpasses;

   /* Which parts of color storage are currently allocated. */
   struct pvr_renderpass_alloc alloc;

   /* Attachment which is currently allocated the on-chip depth/stencil. */
   struct pvr_render_int_attachment *int_ds_attach;

   /* Attachment which is loaded into the on-chip depth/stencil at the start of
    * the render.
    */
   struct pvr_render_int_attachment *ds_load_surface;

   /* Attachment which the depth/stencil attachment should be resolved to at the
    * end of the render.
    */
   struct pvr_render_int_attachment *ds_resolve_surface;

   /* Count of surfaces which are allocated on-chip color storage. */
   uint32_t active_surfaces;

   /* List of attachment/ranges which are allocated on-chip color storage. */
   struct list_head active_surf_list;

   const VkAllocationCallbacks *allocator;
};

struct pvr_render_int_subpass_dsts {
   struct pvr_renderpass_resource *color;
   struct pvr_renderpass_resource incoming_zrep;
   struct pvr_renderpass_resource existing_zrep;
};

struct pvr_render_subpass_depth_params {
   bool existing_ds_is_input;
   bool incoming_ds_is_input;
   uint32_t existing_ds_attach;
};

struct pvr_renderpass_storage_firstuse_buffer {
   /* For each pixel output register/tile buffer location: true if the output
    * register has been allocated in the current render.
    */
   bool used[8U];
};

struct pvr_renderpass_storage_firstuse {
   /* First use information for pixel output registers. */
   struct pvr_renderpass_storage_firstuse_buffer output_reg;

   /* First use information for tile buffers. */
   struct pvr_renderpass_storage_firstuse_buffer *tile_buffers;
};

/** Copy information about allocated color storage. */
static VkResult pvr_copy_alloc(struct pvr_renderpass_context *ctx,
                               struct pvr_renderpass_alloc *dst,
                               struct pvr_renderpass_alloc *src)
{
   dst->output_reg = src->output_reg;
   dst->output_regs_count = src->output_regs_count;

   dst->tile_buffers_count = src->tile_buffers_count;
   if (dst->tile_buffers_count > 0U) {
      dst->tile_buffers =
         vk_alloc(ctx->allocator,
                  sizeof(dst->tile_buffers[0U]) * dst->tile_buffers_count,
                  8,
                  VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
      if (!dst->tile_buffers)
         return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);

      memcpy(dst->tile_buffers,
             src->tile_buffers,
             sizeof(dst->tile_buffers[0U]) * dst->tile_buffers_count);
   } else {
      dst->tile_buffers = NULL;
   }

   return VK_SUCCESS;
}

/** Free information about allocated color storage. */
static void pvr_free_alloc(struct pvr_renderpass_context *ctx,
                           struct pvr_renderpass_alloc *alloc)
{
   if (alloc->tile_buffers)
      vk_free(ctx->allocator, alloc->tile_buffers);

   memset(alloc, 0U, sizeof(*alloc));
}

static void pvr_reset_render(struct pvr_renderpass_context *ctx)
{
   ctx->int_ds_attach = NULL;
   ctx->active_surfaces = 0U;
   list_inithead(&ctx->active_surf_list);

   memset(&ctx->alloc.output_reg, 0U, sizeof(ctx->alloc.output_reg));
   ctx->alloc.output_regs_count = 0U;
   ctx->alloc.tile_buffers_count = 0U;
   ctx->alloc.tile_buffers = NULL;

   ctx->hw_render = NULL;
   ctx->subpasses = NULL;
   ctx->ds_load_surface = NULL;
}

/** Gets the amount of memory to allocate per-core for a tile buffer. */
static uint32_t
pvr_get_tile_buffer_size_per_core(const struct pvr_device *device)
{
   uint32_t clusters =
      PVR_GET_FEATURE_VALUE(&device->pdevice->dev_info, num_clusters, 1U);

   /* Round the number of clusters up to the next power of two. */
   if (!PVR_HAS_FEATURE(&device->pdevice->dev_info, tile_per_usc))
      clusters = util_next_power_of_two(clusters);

   /* Tile buffer is (total number of partitions across all clusters) * 16 * 16
    * (quadrant size in pixels).
    */
   return device->pdevice->dev_runtime_info.total_reserved_partition_size *
          clusters * sizeof(uint32_t);
}

/**
 * Gets the amount of memory to allocate for a tile buffer on the current BVNC.
 */
uint32_t pvr_get_tile_buffer_size(const struct pvr_device *device)
{
   /* On a multicore system duplicate the buffer for each core. */
   return pvr_get_tile_buffer_size_per_core(device) *
          rogue_get_max_num_cores(&device->pdevice->dev_info);
}

static void
pvr_finalise_mrt_setup(const struct pvr_device *device,
                       struct pvr_renderpass_hwsetup_render *hw_render,
                       struct usc_mrt_setup *mrt)
{
   mrt->num_output_regs = hw_render->output_regs_count;
   mrt->num_tile_buffers = hw_render->tile_buffers_count;
   mrt->tile_buffer_size = pvr_get_tile_buffer_size(device);
}

/**
 * Copy information about the number of pixel output registers and tile buffers
 * required for the current render to the output structure.
 */
static void pvr_finalise_po_alloc(const struct pvr_device *device,
                                  struct pvr_renderpass_context *ctx)
{
   struct pvr_renderpass_hwsetup_render *hw_render = ctx->hw_render;

   /* The number of output registers must be a power of two. */
   hw_render->output_regs_count =
      util_next_power_of_two(ctx->alloc.output_regs_count);

   assert(ctx->alloc.tile_buffers_count <= ctx->pass->max_tilebuffer_count);
   hw_render->tile_buffers_count = ctx->alloc.tile_buffers_count;

   /* Copy the number of output registers and tile buffers to each subpass. */
   for (uint32_t i = 0U; i < hw_render->subpass_count; i++) {
      struct pvr_renderpass_hwsetup_subpass *hw_subpass =
         &hw_render->subpasses[i];

      pvr_finalise_mrt_setup(device, hw_render, &hw_subpass->setup);
   }

   pvr_finalise_mrt_setup(device, hw_render, &hw_render->init_setup);
   pvr_finalise_mrt_setup(device, hw_render, &hw_render->eot_setup);
}

/** Mark that device memory must be allocated for an attachment. */
static void pvr_mark_surface_alloc(struct pvr_renderpass_context *ctx,
                                   struct pvr_render_int_attachment *int_attach)
{
   const uint32_t attach_idx = int_attach - ctx->int_attach;

   assert(attach_idx < ctx->pass->attachment_count);
   ctx->hw_setup->surface_allocate[attach_idx] = true;
}

/**
 * Check if there is space in a buffer for storing a render target of a
 * specified size.
 */
static int32_t
pvr_is_space_in_buffer(const struct pvr_device_info *dev_info,
                       struct pvr_renderpass_alloc_buffer *buffer,
                       uint32_t pixel_size)
{
   const uint32_t max_out_regs = rogue_get_max_output_regs_per_pixel(dev_info);
   uint32_t alignment = 1U;

   if (PVR_HAS_FEATURE(dev_info, pbe2_in_xe)) {
      /* For a 64-bit/128-bit source format: the start offset must be even. */
      if (pixel_size == 2U || pixel_size == 4U)
         alignment = 2U;
   }

   assert(pixel_size <= max_out_regs);

   for (uint32_t i = 0U; i <= (max_out_regs - pixel_size); i += alignment) {
      if (!BITSET_TEST_RANGE(buffer->allocs, i, i + pixel_size - 1U))
         return i;
   }

   return -1;
}

static VkResult
pvr_surface_setup_render_init(struct pvr_renderpass_context *ctx,
                              struct pvr_renderpass_storage_firstuse *first_use,
                              struct usc_mrt_resource const *resource,
                              struct pvr_render_pass_attachment *attachment,
                              VkAttachmentLoadOp load_op,
                              bool *use_render_init)
{
   const uint32_t pixel_size =
      DIV_ROUND_UP(vk_format_get_blocksizebits(attachment->vk_format), 32U);
   struct pvr_renderpass_hwsetup_render *hw_render = ctx->hw_render;
   struct pvr_renderpass_storage_firstuse_buffer *buffer;
   uint32_t start;

   /* Check if this is the first use of all the allocated registers. */
   if (resource->type == USC_MRT_RESOURCE_TYPE_OUTPUT_REG) {
      buffer = &first_use->output_reg;
      start = resource->reg.output_reg;
   } else {
      assert(resource->mem.tile_buffer < ctx->alloc.tile_buffers_count);
      buffer = &first_use->tile_buffers[resource->mem.tile_buffer];
      start = resource->mem.offset_dw;
   }

   *use_render_init = true;
   for (uint32_t i = 0U; i < pixel_size; i++) {
      /* Don't initialize at the render level if the output registers were
       * previously allocated a different attachment.
       */
      if (buffer->used[start + i])
         *use_render_init = false;

      /* Don't use render init for future attachments allocated to the same
       * registers.
       */
      buffer->used[start + i] = true;
   }

   if (load_op == VK_ATTACHMENT_LOAD_OP_DONT_CARE)
      *use_render_init = false;

   if (*use_render_init) {
      struct pvr_renderpass_colorinit *new_color_init;
      struct usc_mrt_resource *new_mrt;

      /* Initialize the storage at the start of the render. */
      new_color_init = vk_realloc(ctx->allocator,
                                  hw_render->color_init,
                                  sizeof(hw_render->color_init[0U]) *
                                     (hw_render->color_init_count + 1U),
                                  8U,
                                  VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
      if (!new_color_init)
         return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);

      hw_render->color_init = new_color_init;
      hw_render->color_init[hw_render->color_init_count].index =
         attachment->index;
      hw_render->color_init[hw_render->color_init_count].op = load_op;

      /* Set the destination for the attachment load/clear. */
      assert(hw_render->init_setup.num_render_targets ==
             hw_render->color_init_count);

      new_mrt = vk_realloc(ctx->allocator,
                           hw_render->init_setup.mrt_resources,
                           sizeof(hw_render->init_setup.mrt_resources[0U]) *
                              (hw_render->init_setup.num_render_targets + 1U),
                           8U,
                           VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
      if (!new_mrt)
         return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);

      hw_render->init_setup.mrt_resources = new_mrt;
      hw_render->init_setup
         .mrt_resources[hw_render->init_setup.num_render_targets] = *resource;
      hw_render->init_setup.num_render_targets++;

      hw_render->color_init_count++;
   }

   return VK_SUCCESS;
}

static VkResult
pvr_subpass_setup_render_init(struct pvr_renderpass_context *ctx)
{
   struct pvr_renderpass_hwsetup_render *hw_render = ctx->hw_render;
   struct pvr_renderpass_storage_firstuse first_use = { 0 };
   bool first_ds = true;
   VkResult result;

   if (ctx->alloc.tile_buffers_count > 0U) {
      first_use.tile_buffers = vk_zalloc(ctx->allocator,
                                         sizeof(first_use.tile_buffers[0U]) *
                                            ctx->alloc.tile_buffers_count,
                                         8,
                                         VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
      if (!first_use.tile_buffers)
         return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
   }

   for (uint32_t i = 0U; i < hw_render->subpass_count; i++) {
      struct pvr_renderpass_hwsetup_subpass *hw_subpass =
         &hw_render->subpasses[i];
      struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];
      struct pvr_render_subpass *input_subpass = subpass->input_subpass;

      /* If this is the first depth attachment in the render then clear at the
       * render level, not the subpass level.
       */
      if (first_ds &&
          (hw_subpass->depth_initop == VK_ATTACHMENT_LOAD_OP_CLEAR ||
           hw_subpass->stencil_clear)) {
         struct pvr_render_int_attachment *int_ds_attach;

         assert(input_subpass->depth_stencil_attachment !=
                VK_ATTACHMENT_UNUSED);
         assert(input_subpass->depth_stencil_attachment <
                ctx->pass->attachment_count);
         int_ds_attach =
            &ctx->int_attach[input_subpass->depth_stencil_attachment];

         assert(hw_render->ds_attach_idx == VK_ATTACHMENT_UNUSED ||
                hw_render->ds_attach_idx == int_ds_attach->attachment->index);
         hw_render->ds_attach_idx = int_ds_attach->attachment->index;

         if (hw_subpass->depth_initop == VK_ATTACHMENT_LOAD_OP_CLEAR)
            hw_render->depth_init = VK_ATTACHMENT_LOAD_OP_CLEAR;

         if (hw_subpass->stencil_clear) {
            hw_render->stencil_init = VK_ATTACHMENT_LOAD_OP_CLEAR;
            hw_subpass->stencil_clear = false;
         }
      }

      if (input_subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED)
         first_ds = false;

      for (uint32_t j = 0U; j < input_subpass->color_count; j++) {
         struct usc_mrt_resource *mrt = &hw_subpass->setup.mrt_resources[j];
         const uint32_t attach_idx = input_subpass->color_attachments[j];
         struct pvr_render_int_attachment *int_attach;

         if (attach_idx == VK_ATTACHMENT_UNUSED)
            continue;

         int_attach = &ctx->int_attach[attach_idx];

         assert(vk_format_get_blocksizebits(int_attach->attachment->vk_format) >
                0U);

         /* Is this the first use of the attachment? */
         if (int_attach->first_use == (int32_t)i) {
            /* Set if we should initialize the attachment storage at the
             * render level.
             */
            bool use_render_init;
            result = pvr_surface_setup_render_init(ctx,
                                                   &first_use,
                                                   mrt,
                                                   int_attach->attachment,
                                                   hw_subpass->color_initops[j],
                                                   &use_render_init);
            if (result != VK_SUCCESS) {
               if (!first_use.tile_buffers)
                  free(first_use.tile_buffers);

               return result;
            }

            /* On success don't initialize the attachment at the subpass level.
             */
            if (use_render_init)
               hw_subpass->color_initops[j] = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
         } else {
            /* This attachment is already present in on-chip storage so don't
             * do anything.
             */
            assert(hw_subpass->color_initops[j] ==
                   VK_ATTACHMENT_LOAD_OP_DONT_CARE);
         }
      }
   }

   if (!first_use.tile_buffers)
      free(first_use.tile_buffers);

   return VK_SUCCESS;
}

static void
pvr_mark_storage_allocated_in_buffer(struct pvr_renderpass_alloc_buffer *buffer,
                                     uint32_t start,
                                     uint32_t pixel_size)
{
   assert(!BITSET_TEST_RANGE(buffer->allocs, start, start + pixel_size - 1U));
   BITSET_SET_RANGE(buffer->allocs, start, start + pixel_size - 1U);
}

static VkResult
pvr_mark_storage_allocated(struct pvr_renderpass_context *ctx,
                           struct pvr_renderpass_alloc *alloc,
                           struct pvr_render_pass_attachment *attachment,
                           struct pvr_renderpass_resource *resource)
{
   /* Number of dwords to allocate for the attachment. */
   const uint32_t pixel_size =
      DIV_ROUND_UP(vk_format_get_blocksizebits(attachment->vk_format), 32U);

   if (resource->type == USC_MRT_RESOURCE_TYPE_OUTPUT_REG) {
      /* Update the locations used in the pixel output registers. */
      pvr_mark_storage_allocated_in_buffer(&alloc->output_reg,
                                           resource->reg.output_reg,
                                           pixel_size);

      /* Update the range of pixel output registers used. */
      alloc->output_regs_count =
         MAX2(alloc->output_regs_count, resource->reg.output_reg + pixel_size);
   } else {
      assert(resource->type == USC_MRT_RESOURCE_TYPE_MEMORY);

      if (resource->mem.tile_buffer >= alloc->tile_buffers_count) {
         /* Grow the number of tile buffers. */
         struct pvr_renderpass_alloc_buffer *new_tile_buffers = vk_realloc(
            ctx->allocator,
            alloc->tile_buffers,
            sizeof(alloc->tile_buffers[0U]) * (resource->mem.tile_buffer + 1U),
            8U,
            VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
         if (!new_tile_buffers)
            return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);

         alloc->tile_buffers = new_tile_buffers;
         memset(
            &alloc->tile_buffers[alloc->tile_buffers_count],
            0U,
            sizeof(alloc->tile_buffers[0U]) *
               (resource->mem.tile_buffer + 1U - alloc->tile_buffers_count));
         alloc->tile_buffers_count = resource->mem.tile_buffer + 1U;
         assert(alloc->tile_buffers_count <= ctx->pass->max_tilebuffer_count);
      }

      /* Update the locations used in the tile buffer. */
      pvr_mark_storage_allocated_in_buffer(
         &alloc->tile_buffers[resource->mem.tile_buffer],
         resource->mem.offset_dw,
         pixel_size);

      /* The hardware makes the bit depth of the on-chip storage and memory
       * storage the same so make sure the memory storage is large enough to
       * accommodate the largest render target.
       */
      alloc->output_regs_count =
         MAX2(alloc->output_regs_count, resource->mem.offset_dw + pixel_size);
   }

   return VK_SUCCESS;
}

static VkResult
pvr_surface_alloc_color_storage(const struct pvr_device_info *dev_info,
                                struct pvr_renderpass_context *ctx,
                                struct pvr_renderpass_alloc *alloc,
                                struct pvr_render_pass_attachment *attachment,
                                struct pvr_renderpass_resource *resource)
{
   /* Number of dwords to allocate for the attachment. */
   const uint32_t pixel_size =
      DIV_ROUND_UP(vk_format_get_blocksizebits(attachment->vk_format), 32U);

   /* Try allocating pixel output registers. */
   const int32_t output_reg =
      pvr_is_space_in_buffer(dev_info, &alloc->output_reg, pixel_size);
   if (output_reg != -1) {
      resource->type = USC_MRT_RESOURCE_TYPE_OUTPUT_REG;
      resource->reg.output_reg = (uint32_t)output_reg;
      resource->reg.offset = 0U;
   } else {
      uint32_t i;

      /* Mark the attachment as using a tile buffer. */
      resource->type = USC_MRT_RESOURCE_TYPE_MEMORY;

      /* Try allocating from an existing tile buffer. */
      for (i = 0U; i < alloc->tile_buffers_count; i++) {
         const int32_t tile_buffer_offset =
            pvr_is_space_in_buffer(dev_info,
                                   &alloc->tile_buffers[i],
                                   pixel_size);

         if (tile_buffer_offset != -1) {
            resource->mem.tile_buffer = i;
            resource->mem.offset_dw = (uint32_t)tile_buffer_offset;
            break;
         }
      }

      if (i == alloc->tile_buffers_count) {
         /* Check for reaching the maximum number of tile buffers. */
         if (alloc->tile_buffers_count == ctx->pass->max_tilebuffer_count)
            return vk_error(NULL, VK_ERROR_TOO_MANY_OBJECTS);

         /* Use a newly allocated tile buffer. */
         resource->mem.tile_buffer = i;
         resource->mem.offset_dw = 0U;
      }
   }

   /* Update which parts of the pixel outputs/tile buffers are used. */
   return pvr_mark_storage_allocated(ctx, alloc, attachment, resource);
}

/** Free the storage allocated to an attachment. */
static void
pvr_free_buffer_storage(struct pvr_renderpass_alloc_buffer *buffer,
                        struct pvr_render_int_attachment *int_attach,
                        uint32_t start)
{
   const uint32_t pixel_size = DIV_ROUND_UP(
      vk_format_get_blocksizebits(int_attach->attachment->vk_format),
      32U);

   BITSET_CLEAR_RANGE(buffer->allocs, start, start + pixel_size - 1U);
}

/** Free the storage allocated to an attachment. */
static void
pvr_free_surface_storage(struct pvr_renderpass_context *ctx,
                         struct pvr_render_int_attachment *int_attach)
{
   struct usc_mrt_resource *resource = &int_attach->resource;
   struct pvr_renderpass_alloc *alloc = &ctx->alloc;

   assert(resource->type != USC_MRT_RESOURCE_TYPE_INVALID);

   /* Mark the storage as free. */
   if (resource->type == USC_MRT_RESOURCE_TYPE_OUTPUT_REG) {
      pvr_free_buffer_storage(&alloc->output_reg,
                              int_attach,
                              resource->reg.output_reg);
   } else {
      struct pvr_renderpass_alloc_buffer *tile_buffer;

      assert(resource->type == USC_MRT_RESOURCE_TYPE_MEMORY);

      assert(resource->mem.tile_buffer < alloc->tile_buffers_count);
      tile_buffer = &alloc->tile_buffers[resource->mem.tile_buffer];
      pvr_free_buffer_storage(tile_buffer, int_attach, resource->mem.offset_dw);
   }

   /* Mark that the attachment doesn't have allocated storage. */
   resource->type = USC_MRT_RESOURCE_TYPE_INVALID;

   /* Remove from the list of surfaces with allocated on-chip storage. */
   assert(ctx->active_surfaces > 0U);
   ctx->active_surfaces--;
   list_del(&int_attach->link);
}

static void pvr_reset_surface(struct pvr_renderpass_context *ctx,
                              struct pvr_render_int_attachment *int_attach)
{
   /* Reset information about the range of uses. */
   int_attach->first_use = int_attach->last_use = -1;
   int_attach->z_replicate = false;

   pvr_free_surface_storage(ctx, int_attach);
}

static void
pvr_make_surface_active(struct pvr_renderpass_context *ctx,
                        struct pvr_render_int_attachment *int_attach,
                        uint32_t subpass_num)
{
   /* Add to the list of surfaces with on-chip storage. */
   assert(int_attach->first_use == -1);
   int_attach->first_use = subpass_num;
   ctx->active_surfaces++;
   list_addtail(&int_attach->link, &ctx->active_surf_list);
}

/**
 * For a subpass copy details of storage locations for the input/color to the
 * output structure.
 */
static VkResult
pvr_copy_storage_details(struct pvr_renderpass_context *ctx,
                         struct pvr_renderpass_hwsetup_subpass *hw_subpass,
                         struct pvr_renderpass_subpass *subpass)
{
   struct pvr_render_subpass *input_subpass = subpass->input_subpass;
   const uint32_t max_rts =
      input_subpass->color_count + input_subpass->input_count;
   VkResult result;

   hw_subpass->setup.mrt_resources =
      vk_zalloc(ctx->allocator,
                sizeof(hw_subpass->setup.mrt_resources[0U]) * max_rts,
                8,
                VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
   if (!hw_subpass->setup.mrt_resources) {
      result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
      goto end_copy_storage_details;
   }

   for (uint32_t i = 0U; i < input_subpass->color_count; i++) {
      const uint32_t attach_idx = input_subpass->color_attachments[i];
      struct pvr_render_int_attachment *int_attach;

      if (attach_idx == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[attach_idx];

      /* Record for the subpass where the color attachment is stored. */
      assert(int_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID);
      hw_subpass->setup.mrt_resources[i] = int_attach->resource;
   }

   hw_subpass->setup.num_render_targets = input_subpass->color_count;

   /* For this subpass's input attachments. */
   hw_subpass->input_access = vk_alloc(ctx->allocator,
                                       sizeof(hw_subpass->input_access[0U]) *
                                          input_subpass->input_count,
                                       8,
                                       VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
   if (!hw_subpass->input_access) {
      result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
      goto end_copy_storage_details;
   }

   for (uint32_t i = 0U; i < input_subpass->input_count; i++) {
      const uint32_t attach_idx = input_subpass->input_attachments[i];
      struct pvr_render_int_attachment *int_attach;

      if (attach_idx == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[attach_idx];

      if (int_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID) {
         bool is_color = false;

         /* Access the input attachment from on-chip storage. */
         if (int_attach->z_replicate) {
            hw_subpass->input_access[i].type =
               PVR_RENDERPASS_HWSETUP_INPUT_ACCESS_ONCHIP_ZREPLICATE;
         } else {
            hw_subpass->input_access[i].type =
               PVR_RENDERPASS_HWSETUP_INPUT_ACCESS_ONCHIP;
         }

         /* If this attachment is also a color attachment then point to the
          * color attachment's resource.
          */
         for (uint32_t j = 0U; j < input_subpass->color_count; j++) {
            if (input_subpass->color_attachments[j] == (int32_t)attach_idx) {
               hw_subpass->input_access[i].on_chip_rt = j;
               is_color = true;
               break;
            }
         }

         if (!is_color) {
            const uint32_t num_rts = hw_subpass->setup.num_render_targets;

            hw_subpass->input_access[i].on_chip_rt = num_rts;
            hw_subpass->setup.num_render_targets++;

            /* Record the location of the storage for the attachment. */
            hw_subpass->setup.mrt_resources[num_rts] = int_attach->resource;
         }
      } else {
         /* Access the input attachment from memory. */
         hw_subpass->input_access[i].type =
            PVR_RENDERPASS_HWSETUP_INPUT_ACCESS_OFFCHIP;
         hw_subpass->input_access[i].on_chip_rt = -1;
      }
   }

   return VK_SUCCESS;

end_copy_storage_details:
   if (hw_subpass->input_access) {
      vk_free(ctx->allocator, hw_subpass->input_access);
      hw_subpass->input_access = NULL;
   }

   if (hw_subpass->setup.mrt_resources) {
      vk_free(ctx->allocator, hw_subpass->setup.mrt_resources);
      hw_subpass->setup.mrt_resources = NULL;
   }

   return result;
}

/**
 * For a subpass copy details of any storage location for a replicated version
 * of the depth attachment to the output structure.
 */
static VkResult
pvr_copy_z_replicate_details(struct pvr_renderpass_context *ctx,
                             struct pvr_renderpass_hwsetup_subpass *hw_subpass,
                             struct pvr_renderpass_subpass *subpass)
{
   struct pvr_render_subpass *input_subpass = subpass->input_subpass;
   struct pvr_render_int_attachment *int_ds_attach;
   uint32_t z_replicate;
   bool found = false;

   assert(input_subpass->depth_stencil_attachment >= 0U &&
          input_subpass->depth_stencil_attachment <
             (int32_t)ctx->pass->attachment_count);

   int_ds_attach = &ctx->int_attach[input_subpass->depth_stencil_attachment];

   assert(hw_subpass->z_replicate == -1);

   /* Is the replicated depth also an input attachment? */
   for (uint32_t i = 0U; i < input_subpass->input_count; i++) {
      const uint32_t attach_idx = input_subpass->input_attachments[i];
      struct pvr_render_int_attachment *int_attach;

      if (attach_idx == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[attach_idx];

      if (int_attach == int_ds_attach) {
         z_replicate = hw_subpass->input_access[i].on_chip_rt;
         found = true;
         break;
      }
   }

   if (!found)
      z_replicate = hw_subpass->setup.num_render_targets;

   /* If the Z replicate attachment isn't also an input attachment then grow the
    * array of locations.
    */
   assert(z_replicate <= hw_subpass->setup.num_render_targets);
   if (z_replicate == hw_subpass->setup.num_render_targets) {
      struct usc_mrt_resource *mrt =
         vk_realloc(ctx->allocator,
                    hw_subpass->setup.mrt_resources,
                    sizeof(hw_subpass->setup.mrt_resources[0U]) *
                       (hw_subpass->setup.num_render_targets + 1U),
                    8U,
                    VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
      if (!mrt)
         return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);

      hw_subpass->setup.mrt_resources = mrt;
      hw_subpass->setup.num_render_targets++;
   }

   /* Copy the location of the Z replicate. */
   assert(int_ds_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID);
   hw_subpass->setup.mrt_resources[z_replicate] = int_ds_attach->resource;
   hw_subpass->z_replicate = z_replicate;

   return VK_SUCCESS;
}

static void pvr_dereference_surface(struct pvr_renderpass_context *ctx,
                                    int32_t attach_idx,
                                    uint32_t subpass_num)
{
   struct pvr_render_int_attachment *int_attach = &ctx->int_attach[attach_idx];

   assert(int_attach->remaining_count > 0U);
   int_attach->remaining_count--;

   if (int_attach->remaining_count == 0U) {
      if (int_attach->first_use != -1)
         int_attach->last_use = subpass_num;

      if (int_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID)
         pvr_free_surface_storage(ctx, int_attach);
   }

   if (int_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) {
      assert(int_attach->stencil_remaining_count > 0U);
      int_attach->stencil_remaining_count--;
   }
}

static void pvr_free_render(struct pvr_renderpass_context *ctx)
{
   pvr_free_alloc(ctx, &ctx->alloc);

   if (ctx->subpasses) {
      for (uint32_t i = 0U; i < ctx->hw_render->subpass_count; i++)
         pvr_free_alloc(ctx, &ctx->subpasses[i].alloc);

      vk_free(ctx->allocator, ctx->subpasses);
      ctx->subpasses = NULL;
   }
}

static bool pvr_render_has_side_effects(struct pvr_renderpass_context *ctx)
{
   struct pvr_renderpass_hwsetup_render *hw_render = ctx->hw_render;
   struct pvr_render_pass *pass = ctx->pass;

   if ((hw_render->depth_init == VK_ATTACHMENT_LOAD_OP_CLEAR &&
        hw_render->depth_store) ||
       (hw_render->stencil_init == VK_ATTACHMENT_LOAD_OP_CLEAR &&
        hw_render->stencil_store)) {
      return true;
   }

   for (uint32_t i = 0U; i < hw_render->eot_surface_count; i++) {
      const struct pvr_renderpass_hwsetup_eot_surface *eot_attach =
         &hw_render->eot_surfaces[i];
      const struct pvr_render_pass_attachment *attachment =
         &pass->attachments[eot_attach->attachment_idx];

      if (attachment->load_op == VK_ATTACHMENT_LOAD_OP_CLEAR &&
          attachment->store_op == VK_ATTACHMENT_STORE_OP_STORE) {
         return true;
      }

      if (eot_attach->need_resolve)
         return true;
   }

   return false;
}

static VkResult pvr_close_render(const struct pvr_device *device,
                                 struct pvr_renderpass_context *ctx)
{
   struct pvr_renderpass_hwsetup_render *hw_render = ctx->hw_render;
   struct pvr_renderpass_hwsetup_eot_surface *eot_attach;
   struct usc_mrt_setup *eot_setup;
   int32_t mrt_idx;
   VkResult result;

   /* Render already closed. */
   if (!hw_render)
      return VK_SUCCESS;

   /* Setup render and allocate resources for color/depth loads and clears. */
   result = pvr_subpass_setup_render_init(ctx);
   if (result != VK_SUCCESS)
      return result;

   /* Reset surfaces whose last use was in the current render. */
   list_for_each_entry_safe (struct pvr_render_int_attachment,
                             int_attach,
                             &ctx->active_surf_list,
                             link) {
      if (int_attach->last_use != -1) {
         assert(int_attach->resource.type == USC_MRT_RESOURCE_TYPE_INVALID);
         pvr_reset_surface(ctx, int_attach);
      }
   }

   /* Check if the depth attachment has uses in future subpasses. */
   if (ctx->int_ds_attach) {
      /* Store the depth to the attachment at the end of the render. */
      if (ctx->int_ds_attach->remaining_count > 0U)
         hw_render->depth_store = true;

      /* Store the stencil to the attachment at the end of the render. */
      if (ctx->int_ds_attach->stencil_remaining_count > 0U)
         hw_render->stencil_store = true;

      if (hw_render->depth_store || hw_render->stencil_store) {
         assert(hw_render->ds_attach_idx == VK_ATTACHMENT_UNUSED ||
                hw_render->ds_attach_idx ==
                   ctx->int_ds_attach->attachment->index);
         hw_render->ds_attach_idx = ctx->int_ds_attach->attachment->index;

         /* Allocate memory for the attachment. */
         pvr_mark_surface_alloc(ctx, ctx->int_ds_attach);
      }

      /* Load the depth and stencil before the next use. */
      ctx->int_ds_attach->load_op = VK_ATTACHMENT_LOAD_OP_LOAD;
      ctx->int_ds_attach->stencil_load_op = VK_ATTACHMENT_LOAD_OP_LOAD;
   }

   eot_setup = &hw_render->eot_setup;
   memset(eot_setup, 0U, sizeof(*eot_setup));

   /* Set the number of pixel output registers/tile buffers allocated for the
    * render and copy the information to all subpasses and the EOT program.
    */
   pvr_finalise_po_alloc(device, ctx);

   /* If any attachment are used with z replicate then they will be stored to by
    * the ISP. So remove them from the list to store to using the PBE.
    */
   list_for_each_entry_safe (struct pvr_render_int_attachment,
                             int_attach,
                             &ctx->active_surf_list,
                             link) {
      if (int_attach->z_replicate)
         pvr_reset_surface(ctx, int_attach);
   }

   /* Number of surfaces with allocated on-chip storage. */
   eot_setup->num_render_targets = ctx->active_surfaces;
   eot_setup->mrt_resources = vk_alloc(ctx->allocator,
                                       sizeof(eot_setup->mrt_resources[0U]) *
                                          eot_setup->num_render_targets,
                                       8,
                                       VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
   if (!eot_setup->mrt_resources)
      return vk_error(device, VK_ERROR_OUT_OF_HOST_MEMORY);

   /* Record the location of the on-chip storage. */
   mrt_idx = 0U;
   list_for_each_entry_safe (struct pvr_render_int_attachment,
                             int_attach,
                             &ctx->active_surf_list,
                             link) {
      assert(int_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID);
      assert(int_attach->remaining_count > 0U);
      if (int_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT)
         assert(int_attach->stencil_remaining_count > 0U);

      /* Copy the location of the source data for this attachment. */
      eot_setup->mrt_resources[mrt_idx] = int_attach->resource;

      assert(int_attach->mrt_idx == -1);
      int_attach->mrt_idx = mrt_idx;

      mrt_idx++;
   }
   assert(mrt_idx == (int32_t)eot_setup->num_render_targets);

   hw_render->eot_surface_count = 0U;
   hw_render->pbe_emits = 0U;

   /* Count the number of surfaces to store to at the end of the subpass. */
   for (uint32_t i = 0U; i < hw_render->subpass_count; i++) {
      struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];
      struct pvr_render_subpass *input_subpass = subpass->input_subpass;

      for (uint32_t j = 0U; j < input_subpass->color_count; j++) {
         const uint32_t resolve_output =
            input_subpass->resolve_attachments
               ? input_subpass->resolve_attachments[j]
               : VK_ATTACHMENT_UNUSED;
         struct pvr_render_int_attachment *color_attach;

         if (input_subpass->color_attachments[j] == VK_ATTACHMENT_UNUSED)
            continue;

         color_attach = &ctx->int_attach[input_subpass->color_attachments[j]];

         if (list_is_linked(&color_attach->link)) {
            uint32_t rem_count = resolve_output == VK_ATTACHMENT_UNUSED ? 0U
                                                                        : 1U;

            /* If a color attachment is resolved it will have an extra
             * remaining usage.
             */
            if (color_attach->remaining_count > rem_count &&
                !color_attach->eot_surf_required) {
               color_attach->eot_surf_required = true;
               hw_render->eot_surface_count++;
            }
         }

         if (resolve_output != VK_ATTACHMENT_UNUSED) {
            struct pvr_render_int_attachment *int_resolve_attach =
               &ctx->int_attach[resolve_output];

            if (!int_resolve_attach->eot_surf_required) {
               int_resolve_attach->eot_surf_required = true;
               hw_render->eot_surface_count++;
            }
         }
      }
   }

   assert(hw_render->eot_surface_count <= 16U);

   hw_render->eot_surfaces = vk_alloc(ctx->allocator,
                                      sizeof(hw_render->eot_surfaces[0U]) *
                                         hw_render->eot_surface_count,
                                      8,
                                      VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
   if (!hw_render->eot_surfaces)
      return vk_error(device, VK_ERROR_OUT_OF_HOST_MEMORY);

   eot_attach = hw_render->eot_surfaces;

   for (uint32_t i = 0U; i < hw_render->subpass_count; i++) {
      struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];
      struct pvr_render_subpass *input_subpass = subpass->input_subpass;

      for (uint32_t j = 0U; j < input_subpass->color_count; j++) {
         const uint32_t resolve_output =
            input_subpass->resolve_attachments
               ? input_subpass->resolve_attachments[j]
               : VK_ATTACHMENT_UNUSED;
         struct pvr_render_int_attachment *color_attach;

         if (input_subpass->color_attachments[j] == VK_ATTACHMENT_UNUSED)
            continue;

         color_attach = &ctx->int_attach[input_subpass->color_attachments[j]];

         if (resolve_output != VK_ATTACHMENT_UNUSED) {
            struct pvr_render_int_attachment *resolve_src =
               &ctx->int_attach[input_subpass->color_attachments[j]];
            struct pvr_render_int_attachment *resolve_dst =
               &ctx->int_attach[resolve_output];

            assert(resolve_dst->eot_surf_required);
            resolve_dst->eot_surf_required = false;

            /* Dereference the source to the resolve. */
            assert(resolve_src->remaining_count > 0U);
            resolve_src->remaining_count--;

            /* Allocate device memory for the resolve destination. */
            pvr_mark_surface_alloc(ctx, resolve_dst);

            /* The attachment has been written so load the attachment the
             * next time it is referenced.
             */
            resolve_dst->load_op = VK_ATTACHMENT_LOAD_OP_LOAD;

            eot_attach->mrt_idx = resolve_src->mrt_idx;
            eot_attach->attachment_idx = resolve_dst->attachment->index;
            eot_attach->src_attachment_idx = resolve_src->attachment->index;

            eot_attach->need_resolve = true;

            if (!resolve_src->is_pbe_downscalable) {
               /* Resolve src must be stored for transfer resolve. */
               assert(resolve_src->remaining_count > 0U);

               eot_attach->resolve_type = PVR_RESOLVE_TYPE_TRANSFER;
            } else if (resolve_src->remaining_count == 0U) {
               eot_attach->resolve_type = PVR_RESOLVE_TYPE_PBE;
               hw_render->pbe_emits++;
            } else {
               eot_attach->resolve_type = PVR_RESOLVE_TYPE_INVALID;
            }

            eot_attach++;
         }

         if (color_attach->eot_surf_required) {
            assert(color_attach->remaining_count > 0U);

            pvr_mark_surface_alloc(ctx, color_attach);

            assert(color_attach->mrt_idx >= 0);
            assert(color_attach->mrt_idx <
                   (int32_t)hw_render->eot_setup.num_render_targets);

            eot_attach->mrt_idx = color_attach->mrt_idx;
            eot_attach->attachment_idx = color_attach->attachment->index;
            eot_attach->need_resolve = false;
            eot_attach++;

            hw_render->pbe_emits++;

            color_attach->eot_surf_required = false;
         }
      }
   }

   assert(hw_render->pbe_emits <= PVR_NUM_PBE_EMIT_REGS);

   /* Count the number of extra resolves we can do through the PBE. */
   for (uint32_t i = 0U; i < hw_render->eot_surface_count; i++) {
      eot_attach = &hw_render->eot_surfaces[i];

      if (eot_attach->need_resolve &&
          eot_attach->resolve_type == PVR_RESOLVE_TYPE_INVALID) {
         if (hw_render->pbe_emits == PVR_NUM_PBE_EMIT_REGS) {
            eot_attach->resolve_type = PVR_RESOLVE_TYPE_TRANSFER;
         } else {
            eot_attach->resolve_type = PVR_RESOLVE_TYPE_PBE;
            hw_render->pbe_emits++;
         }
      }
   }

   assert(hw_render->pbe_emits <= PVR_NUM_PBE_EMIT_REGS);

   /* Check for side effects in the final render. */
   hw_render->has_side_effects = pvr_render_has_side_effects(ctx);

   /* Reset active surfaces. */
   list_for_each_entry_safe (struct pvr_render_int_attachment,
                             int_attach,
                             &ctx->active_surf_list,
                             link) {
      int_attach->mrt_idx = -1;
      pvr_reset_surface(ctx, int_attach);
   }

   assert(ctx->active_surfaces == 0U);
   assert(list_is_empty(&ctx->active_surf_list));

   pvr_free_render(ctx);
   pvr_reset_render(ctx);

   return VK_SUCCESS;
}

static bool pvr_is_input(struct pvr_render_subpass *subpass,
                         uint32_t attach_idx)
{
   if (attach_idx == VK_ATTACHMENT_UNUSED)
      return false;

   for (uint32_t i = 0U; i < subpass->input_count; i++) {
      if (subpass->input_attachments[i] == attach_idx)
         return true;
   }

   return false;
}

static bool
pvr_depth_zls_conflict(struct pvr_renderpass_context *ctx,
                       struct pvr_render_int_attachment *int_ds_attach,
                       bool existing_ds_is_input)
{
   if (!ctx->int_ds_attach)
      return false;

   /* No conflict if the incoming subpass doesn't have a depth/stencil
    * attachment.
    */
   if (!int_ds_attach)
      return false;

   /* No conflict if the incoming depth/stencil attachment is the same as the
    * existing one.
    */
   if (ctx->int_ds_attach == int_ds_attach)
      return false;

   /* If the existing depth/stencil attachment is used later, then we can't
    * overwrite it.
    *
    * The exception is if the only use is as an input attachment in the incoming
    * subpass in which case we can use the Z replicate feature to save the
    * value.
    */
   if (ctx->int_ds_attach->remaining_count > 0U &&
       !(existing_ds_is_input && ctx->int_ds_attach->remaining_count == 1U)) {
      return true;
   }

   if (ctx->int_ds_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT &&
       ctx->int_ds_attach->stencil_remaining_count > 0U) {
      return true;
   }

   /* We can't load midrender so fail if the new depth/stencil attachment is
    * already initialized.
    */
   if (int_ds_attach->load_op == VK_ATTACHMENT_LOAD_OP_LOAD)
      return true;

   if (int_ds_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT &&
       int_ds_attach->stencil_load_op == VK_ATTACHMENT_LOAD_OP_LOAD) {
      return true;
   }

   return false;
}

static void
pvr_set_surface_resource(struct pvr_render_int_attachment *int_attach,
                         struct pvr_renderpass_resource *resource)
{
   int_attach->resource.type = resource->type;

   switch (resource->type) {
   case USC_MRT_RESOURCE_TYPE_OUTPUT_REG:
      int_attach->resource.reg.output_reg = resource->reg.output_reg;
      int_attach->resource.reg.offset = resource->reg.offset;
      break;

   case USC_MRT_RESOURCE_TYPE_MEMORY:
      int_attach->resource.mem.tile_buffer = resource->mem.tile_buffer;
      int_attach->resource.mem.offset_dw = resource->mem.offset_dw;
      break;

   default:
      break;
   }
}

static bool pvr_equal_resources(struct pvr_renderpass_resource *resource1,
                                struct pvr_renderpass_resource *resource2)
{
   if (resource1->type != resource2->type)
      return false;

   switch (resource1->type) {
   case USC_MRT_RESOURCE_TYPE_OUTPUT_REG:
      return resource1->reg.output_reg == resource2->reg.output_reg &&
             resource1->reg.offset == resource2->reg.offset;

   case USC_MRT_RESOURCE_TYPE_MEMORY:
      return resource1->mem.tile_buffer == resource2->mem.tile_buffer &&
             resource1->mem.offset_dw == resource2->mem.offset_dw;

   default:
      return true;
   }
}

static VkResult
pvr_enable_z_replicate(struct pvr_renderpass_context *ctx,
                       struct pvr_renderpass_hwsetup_render *hw_render,
                       int32_t replicate_attach_idx,
                       struct pvr_renderpass_resource *replicate_dst)
{
   struct pvr_render_int_attachment *int_attach =
      &ctx->int_attach[replicate_attach_idx];
   int32_t first_use = -1;

   /* If Z replication was already enabled for the attachment then nothing more
    * to do.
    */
   if (!int_attach->z_replicate) {
      /* Copy details of the storage for the replicated value to the attachment.
       */
      assert(int_attach->resource.type == USC_MRT_RESOURCE_TYPE_INVALID);
      assert(replicate_dst->type != USC_MRT_RESOURCE_TYPE_INVALID);
      pvr_set_surface_resource(int_attach, replicate_dst);
   } else {
      assert(int_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID);
      assert(replicate_dst->type == USC_MRT_RESOURCE_TYPE_INVALID);
   }

   /* Find the first subpass where the attachment is written. */
   for (uint32_t i = 0U; i < hw_render->subpass_count; i++) {
      struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];
      struct pvr_render_subpass *input_subpass = subpass->input_subpass;

      if (input_subpass->depth_stencil_attachment == replicate_attach_idx) {
         first_use = i;
         break;
      }
   }
   assert(first_use >= 0);

   /* For all subpasses from the first write. */
   for (uint32_t i = first_use; i < hw_render->subpass_count; i++) {
      struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];
      struct pvr_render_subpass *input_subpass = subpass->input_subpass;

      /* If the subpass writes to the attachment then enable z replication. */
      if (input_subpass->depth_stencil_attachment == replicate_attach_idx &&
          !subpass->z_replicate) {
         subpass->z_replicate = true;

         if (i != (hw_render->subpass_count - 1U)) {
            /* Copy the details of the storage for replicated value. */
            const VkResult result =
               pvr_copy_z_replicate_details(ctx,
                                            &ctx->hw_render->subpasses[i],
                                            subpass);
            if (result != VK_SUCCESS)
               return result;
         }
      }
   }

   if (!int_attach->z_replicate) {
      /* Add the storage for the replicated value to locations in use at each
       * subpass.
       */
      for (uint32_t i = first_use; i < (hw_render->subpass_count - 1U); i++) {
         struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];

         pvr_mark_storage_allocated(ctx,
                                    &subpass->alloc,
                                    int_attach->attachment,
                                    replicate_dst);
      }

      /* Add the depth attachment to the list of surfaces with allocated
       * storage.
       */
      pvr_make_surface_active(ctx, int_attach, first_use);

      int_attach->z_replicate = true;
   }

   return VK_SUCCESS;
}

static bool pvr_is_pending_resolve_dest(struct pvr_renderpass_context *ctx,
                                        uint32_t attach_idx)
{
   struct pvr_render_int_attachment *int_attach = &ctx->int_attach[attach_idx];

   return int_attach->last_resolve_dst_render != -1 &&
          int_attach->last_resolve_dst_render ==
             (int32_t)(ctx->hw_setup->render_count - 1U);
}

static bool pvr_is_pending_resolve_src(struct pvr_renderpass_context *ctx,
                                       uint32_t attach_idx)
{
   struct pvr_render_int_attachment *int_attach = &ctx->int_attach[attach_idx];

   return int_attach->last_resolve_src_render != -1 &&
          int_attach->last_resolve_src_render ==
             (int32_t)(ctx->hw_setup->render_count - 1U);
}

static bool pvr_exceeds_pbe_registers(struct pvr_renderpass_context *ctx,
                                      struct pvr_render_subpass *subpass)
{
   int32_t live_outputs[PVR_NUM_PBE_EMIT_REGS];
   uint32_t num_live_outputs = 0U;

   /* Count all color outputs so far. */
   for (uint32_t i = 0U; i < ctx->hw_render->subpass_count; i++) {
      struct pvr_render_subpass *input_subpass =
         ctx->subpasses[i].input_subpass;

      for (uint32_t j = 0U; j < input_subpass->color_count; j++) {
         const uint32_t global_color_attach =
            input_subpass->color_attachments[j];
         struct pvr_render_int_attachment *int_attach;
         bool found = false;

         if (global_color_attach == VK_ATTACHMENT_UNUSED)
            continue;

         int_attach = &ctx->int_attach[global_color_attach];

         if (int_attach->last_read <= (int32_t)subpass->index)
            continue;

         for (uint32_t k = 0U; k < num_live_outputs; k++) {
            if (live_outputs[k] == global_color_attach) {
               found = true;
               break;
            }
         }

         if (!found)
            live_outputs[num_live_outputs++] = global_color_attach;
      }
   }

   assert(num_live_outputs <= PVR_NUM_PBE_EMIT_REGS);

   /* Check if adding all the color outputs of the new subpass to the render
    * would exceed the limit.
    */
   for (uint32_t i = 0U; i < subpass->color_count; i++) {
      const uint32_t global_color_attach = subpass->color_attachments[i];
      struct pvr_render_int_attachment *int_attach;
      bool found = false;

      if (global_color_attach == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[global_color_attach];

      if (int_attach->last_read <= (int32_t)subpass->index)
         continue;

      for (uint32_t j = 0U; j < num_live_outputs; j++) {
         if (live_outputs[j] == global_color_attach) {
            found = true;
            break;
         }
      }

      if (!found) {
         if (num_live_outputs >= PVR_NUM_PBE_EMIT_REGS)
            return true;

         live_outputs[num_live_outputs++] = global_color_attach;
      }
   }

   return false;
}

static void pvr_merge_alloc_buffer(struct pvr_renderpass_alloc_buffer *dst,
                                   struct pvr_renderpass_alloc_buffer *src)
{
   for (uint32_t i = 0U; i < ARRAY_SIZE(dst->allocs); i++)
      dst->allocs[i] |= src->allocs[i];
}

static VkResult pvr_merge_alloc(struct pvr_renderpass_context *ctx,
                                struct pvr_renderpass_alloc *dst,
                                struct pvr_renderpass_alloc *src)
{
   pvr_merge_alloc_buffer(&dst->output_reg, &src->output_reg);

   dst->output_regs_count =
      MAX2(dst->output_regs_count, src->output_regs_count);

   if (dst->tile_buffers_count < src->tile_buffers_count) {
      struct pvr_renderpass_alloc_buffer *new_tile_buffers =
         vk_realloc(ctx->allocator,
                    dst->tile_buffers,
                    sizeof(dst->tile_buffers[0U]) * src->tile_buffers_count,
                    8U,
                    VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
      if (!new_tile_buffers)
         return vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);

      dst->tile_buffers = new_tile_buffers;
      memset(dst->tile_buffers + dst->tile_buffers_count,
             0U,
             sizeof(dst->tile_buffers[0U]) *
                (src->tile_buffers_count - dst->tile_buffers_count));
      dst->tile_buffers_count = src->tile_buffers_count;
   }

   for (uint32_t i = 0U; i < src->tile_buffers_count; i++)
      pvr_merge_alloc_buffer(&dst->tile_buffers[i], &src->tile_buffers[i]);

   return VK_SUCCESS;
}

static VkResult
pvr_is_z_replicate_space_available(const struct pvr_device_info *dev_info,
                                   struct pvr_renderpass_context *ctx,
                                   struct pvr_renderpass_alloc *alloc,
                                   uint32_t attach_idx,
                                   struct pvr_renderpass_resource *resource)
{
   struct pvr_renderpass_hwsetup_render *hw_render = ctx->hw_render;
   struct pvr_render_int_attachment *int_attach;
   struct pvr_renderpass_alloc combined_alloc;
   uint32_t first_use;
   VkResult result;

   /* If z replication was already enabled by a previous subpass then storage
    * will already be allocated.
    */
   assert(attach_idx < ctx->pass->attachment_count);

   int_attach = &ctx->int_attach[attach_idx];
   if (int_attach->z_replicate) {
      assert(int_attach->resource.type != USC_MRT_RESOURCE_TYPE_INVALID);
      return VK_SUCCESS;
   }

   /* Find the subpass where the depth is first written. */
   if (hw_render) {
      first_use = hw_render->subpass_count;
      for (uint32_t i = 0U; i < hw_render->subpass_count; i++) {
         struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];
         struct pvr_render_subpass *input_subpass = subpass->input_subpass;

         if (input_subpass->depth_stencil_attachment == (int32_t)attach_idx) {
            first_use = i;
            break;
         }
      }
   }

   /* Get the registers used in any subpass after the depth is first written.
    * Start with registers used in the incoming subpass.
    */
   result = pvr_copy_alloc(ctx, &combined_alloc, alloc);
   if (result != VK_SUCCESS)
      return result;

   if (hw_render) {
      /* Merge in registers used in previous subpasses. */
      for (uint32_t i = first_use; i < hw_render->subpass_count; i++) {
         struct pvr_renderpass_subpass *subpass = &ctx->subpasses[i];

         result = pvr_merge_alloc(ctx, &combined_alloc, &subpass->alloc);
         if (result != VK_SUCCESS) {
            pvr_free_alloc(ctx, &combined_alloc);
            return result;
         }
      }
   }

   result = pvr_surface_alloc_color_storage(dev_info,
                                            ctx,
                                            &combined_alloc,
                                            int_attach->attachment,
                                            resource);

   pvr_free_alloc(ctx, &combined_alloc);
   if (result != VK_SUCCESS)
      return result;

   return pvr_mark_storage_allocated(ctx,
                                     alloc,
                                     int_attach->attachment,
                                     resource);
}

static VkResult
pvr_is_subpass_space_available(const struct pvr_device_info *dev_info,
                               struct pvr_renderpass_context *ctx,
                               struct pvr_render_subpass *subpass,
                               struct pvr_render_subpass_depth_params *sp_depth,
                               struct pvr_renderpass_alloc *alloc,
                               struct pvr_render_int_subpass_dsts *sp_dsts)
{
   VkResult result;

   /* Mark pointers in return structures as not allocated. */
   sp_dsts->color = NULL;
   alloc->tile_buffers = NULL;

   /* Allocate space for which locations are in use after this subpass. */
   result = pvr_copy_alloc(ctx, alloc, &ctx->alloc);
   if (result != VK_SUCCESS)
      return result;

   /* Allocate space to store our results. */
   if (subpass->color_count > 0U) {
      sp_dsts->color =
         vk_alloc(ctx->allocator,
                  sizeof(sp_dsts->color[0U]) * subpass->color_count,
                  8,
                  VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
      if (!sp_dsts->color) {
         result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
         goto err_free_alloc;
      }
   } else {
      sp_dsts->color = NULL;
   }

   sp_dsts->existing_zrep.type = USC_MRT_RESOURCE_TYPE_INVALID;
   sp_dsts->incoming_zrep.type = USC_MRT_RESOURCE_TYPE_INVALID;

   for (uint32_t i = 0U; i < subpass->color_count; i++) {
      const uint32_t attach_idx = subpass->color_attachments[i];
      struct pvr_render_int_attachment *int_attach;

      if (attach_idx == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[attach_idx];

      assert(vk_format_get_blocksizebits(int_attach->attachment->vk_format) >
             0U);

      /* Is the attachment not allocated on-chip storage? */
      if (int_attach->resource.type == USC_MRT_RESOURCE_TYPE_INVALID) {
         result = pvr_surface_alloc_color_storage(dev_info,
                                                  ctx,
                                                  alloc,
                                                  int_attach->attachment,
                                                  &sp_dsts->color[i]);
         if (result != VK_SUCCESS)
            goto err_free_alloc;

         /* Avoid merging subpasses which result in tile buffers having to be
          * used. The benefit of merging must be weighed against the cost of
          * writing/reading to tile buffers.
          */
         if (ctx->hw_render &&
             sp_dsts->color[i].type != USC_MRT_RESOURCE_TYPE_OUTPUT_REG) {
            result = vk_error(NULL, VK_ERROR_TOO_MANY_OBJECTS);
            goto err_free_alloc;
         }
      } else {
         sp_dsts->color[i].type = USC_MRT_RESOURCE_TYPE_INVALID;
      }
   }

   if (sp_depth->existing_ds_is_input) {
      result = pvr_is_z_replicate_space_available(dev_info,
                                                  ctx,
                                                  alloc,
                                                  sp_depth->existing_ds_attach,
                                                  &sp_dsts->existing_zrep);
      if (result != VK_SUCCESS)
         goto err_free_alloc;
   }

   if (sp_depth->incoming_ds_is_input) {
      if (sp_depth->existing_ds_attach != subpass->depth_stencil_attachment) {
         result = pvr_is_z_replicate_space_available(
            dev_info,
            ctx,
            alloc,
            subpass->depth_stencil_attachment,
            &sp_dsts->incoming_zrep);
         if (result != VK_SUCCESS)
            goto err_free_alloc;
      } else {
         sp_dsts->incoming_zrep = sp_dsts->existing_zrep;
      }
   }

   return VK_SUCCESS;

err_free_alloc:
   pvr_free_alloc(ctx, alloc);
   if (sp_dsts->color)
      vk_free(ctx->allocator, sp_dsts->color);

   sp_dsts->color = NULL;

   return result;
}

static bool
pvr_can_combine_with_render(const struct pvr_device_info *dev_info,
                            struct pvr_renderpass_context *ctx,
                            struct pvr_render_subpass *subpass,
                            struct pvr_render_subpass_depth_params *sp_depth,
                            struct pvr_render_int_attachment *int_ds_attach,
                            struct pvr_renderpass_alloc *new_alloc,
                            struct pvr_render_int_subpass_dsts *sp_dsts)
{
   VkResult result;
   bool ret;

   /* Mark pointers in return structures as not allocated. */
   sp_dsts->color = NULL;
   new_alloc->tile_buffers = NULL;

   /* The hardware doesn't support replicating the stencil, so we need to store
    * the depth to memory if a stencil attachment is used as an input
    * attachment.
    */
   if (sp_depth->existing_ds_is_input &&
       ctx->int_ds_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) {
      return false;
   }

   if (sp_depth->incoming_ds_is_input && int_ds_attach &&
       int_ds_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT &&
       ctx->hw_render) {
      return false;
   }

   /* Can't mix multiple sample counts into same render. */
   if (ctx->hw_render &&
       ctx->hw_render->sample_count != subpass->sample_count) {
      return false;
   }

   /* If the depth is used by both the render and the incoming subpass and
    * either the existing depth must be saved or the new depth must be loaded
    * then we can't merge.
    */
   ret = pvr_depth_zls_conflict(ctx,
                                int_ds_attach,
                                sp_depth->existing_ds_is_input);
   if (ret)
      return false;

   /* Check if any of the subpass's dependencies are marked that the two
    * subpasses can't be in the same render.
    */
   for (uint32_t i = 0U; i < subpass->dep_count; i++) {
      const uint32_t dep = subpass->dep_list[i];
      if (subpass->flush_on_dep[i] && ctx->hw_setup->subpass_map[dep].render ==
                                         (ctx->hw_setup->render_count - 1U)) {
         return false;
      }
   }

   /* Check if one of the input/color attachments is written by an MSAA resolve
    * in an existing subpass in the current render.
    */
   for (uint32_t i = 0U; i < subpass->input_count; i++) {
      const uint32_t attach_idx = subpass->input_attachments[i];
      if (attach_idx != VK_ATTACHMENT_UNUSED &&
          pvr_is_pending_resolve_dest(ctx, attach_idx)) {
         return false;
      }
   }

   for (uint32_t i = 0U; i < subpass->color_count; i++) {
      if (subpass->color_attachments[i] != VK_ATTACHMENT_UNUSED &&
          (pvr_is_pending_resolve_dest(ctx, subpass->color_attachments[i]) ||
           pvr_is_pending_resolve_src(ctx, subpass->color_attachments[i]))) {
         return false;
      }

      if (subpass->resolve_attachments &&
          subpass->resolve_attachments[i] != VK_ATTACHMENT_UNUSED &&
          pvr_is_pending_resolve_dest(ctx, subpass->resolve_attachments[i])) {
         return false;
      }
   }

   /* No chance of exceeding PBE registers in a single subpass. */
   if (ctx->hw_render) {
      ret = pvr_exceeds_pbe_registers(ctx, subpass);
      if (ret)
         return false;
   }

   /* Check we can allocate storage for the new subpass's color attachments and
    * any z replications.
    */
   result = pvr_is_subpass_space_available(dev_info,
                                           ctx,
                                           subpass,
                                           sp_depth,
                                           new_alloc,
                                           sp_dsts);
   if (result != VK_SUCCESS)
      return false;

   return true;
}

static VkResult
pvr_merge_subpass(const struct pvr_device *device,
                  struct pvr_renderpass_context *ctx,
                  struct pvr_render_subpass *input_subpass,
                  struct pvr_renderpass_hwsetup_subpass **const hw_subpass_out)
{
   struct pvr_renderpass_hwsetup_subpass *new_hw_subpasses;
   struct pvr_renderpass_hwsetup_subpass *hw_subpass;
   struct pvr_render_int_attachment *int_ds_attach;
   struct pvr_renderpass_hwsetup_render *hw_render;
   struct pvr_render_subpass_depth_params sp_depth;
   struct pvr_renderpass_subpass *new_subpasses;
   struct pvr_render_int_subpass_dsts sp_dsts;
   struct pvr_renderpass_subpass *subpass;
   struct pvr_renderpass_alloc alloc;
   VkResult result;
   bool ret;

   /* Depth attachment for the incoming subpass. */
   if (input_subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED)
      int_ds_attach = &ctx->int_attach[input_subpass->depth_stencil_attachment];
   else
      int_ds_attach = NULL;

   /* Attachment ID for the existing depth attachment. */
   if (ctx->int_ds_attach)
      sp_depth.existing_ds_attach = ctx->int_ds_attach - ctx->int_attach;
   else
      sp_depth.existing_ds_attach = VK_ATTACHMENT_UNUSED;

   /* Is the incoming depth attachment used as an input to the incoming subpass?
    */
   sp_depth.incoming_ds_is_input =
      pvr_is_input(input_subpass, input_subpass->depth_stencil_attachment);

   /* Is the current depth attachment used as an input to the incoming subpass?
    */
   sp_depth.existing_ds_is_input =
      pvr_is_input(input_subpass, sp_depth.existing_ds_attach);

   /* Can the incoming subpass be combined with the existing render? Also checks
    * if space is available for the subpass results and return the allocated
    * locations.
    */
   ret = pvr_can_combine_with_render(&device->pdevice->dev_info,
                                     ctx,
                                     input_subpass,
                                     &sp_depth,
                                     int_ds_attach,
                                     &alloc,
                                     &sp_dsts);
   if (!ret) {
      result = pvr_close_render(device, ctx);
      if (result != VK_SUCCESS)
         goto end_merge_subpass;

      sp_depth.existing_ds_is_input = false;
      sp_depth.existing_ds_attach = VK_ATTACHMENT_UNUSED;

      /* Allocate again in a new render. */
      result = pvr_is_subpass_space_available(&device->pdevice->dev_info,
                                              ctx,
                                              input_subpass,
                                              &sp_depth,
                                              &alloc,
                                              &sp_dsts);
      assert(result != VK_ERROR_TOO_MANY_OBJECTS);
      if (result != VK_SUCCESS)
         goto end_merge_subpass;
   }

   /* If there isn't an in-progress render then allocate one. */
   if (!ctx->hw_render) {
      struct pvr_renderpass_hwsetup *hw_setup = ctx->hw_setup;
      struct pvr_renderpass_hwsetup_render *new_hw_render = vk_realloc(
         ctx->allocator,
         hw_setup->renders,
         sizeof(hw_setup->renders[0U]) * (hw_setup->render_count + 1U),
         8U,
         VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
      if (!new_hw_render) {
         result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
         goto end_merge_subpass;
      }

      hw_setup->renders = new_hw_render;

      ctx->hw_render = &hw_setup->renders[hw_setup->render_count];
      memset(ctx->hw_render, 0U, sizeof(*hw_render));
      ctx->hw_render->ds_attach_idx = VK_ATTACHMENT_UNUSED;
      hw_setup->render_count++;
      ctx->hw_render->depth_init = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
      ctx->hw_render->stencil_init = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
      ctx->hw_render->sample_count = input_subpass->sample_count;
   }

   /* Allocate a new subpass in the in-progress render. */
   hw_render = ctx->hw_render;

   new_hw_subpasses = vk_realloc(ctx->allocator,
                                 hw_render->subpasses,
                                 sizeof(hw_render->subpasses[0U]) *
                                    (hw_render->subpass_count + 1U),
                                 8U,
                                 VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
   if (!new_hw_subpasses) {
      result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
      goto end_merge_subpass;
   }

   hw_render->subpasses = new_hw_subpasses;
   hw_subpass = &hw_render->subpasses[hw_render->subpass_count];

   new_subpasses =
      vk_realloc(ctx->allocator,
                 ctx->subpasses,
                 sizeof(ctx->subpasses[0U]) * (hw_render->subpass_count + 1U),
                 8U,
                 VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
   if (!new_subpasses) {
      result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
      goto end_merge_subpass;
   }

   ctx->subpasses = new_subpasses;

   subpass = &ctx->subpasses[hw_render->subpass_count];
   subpass->input_subpass = input_subpass;
   subpass->z_replicate = false;

   /* Save the allocation state at the subpass. */
   result = pvr_copy_alloc(ctx, &subpass->alloc, &alloc);
   if (result != VK_SUCCESS)
      goto end_merge_subpass;

   hw_render->subpass_count++;

   memset(hw_subpass, 0U, sizeof(*hw_subpass));
   hw_subpass->index = input_subpass->index;
   hw_subpass->z_replicate = -1;
   hw_subpass->depth_initop = VK_ATTACHMENT_LOAD_OP_DONT_CARE;

   if (int_ds_attach && ctx->int_ds_attach != int_ds_attach) {
      bool setup_render_ds = false;
      bool stencil_load = false;
      bool depth_load = false;

      if (int_ds_attach->load_op == VK_ATTACHMENT_LOAD_OP_LOAD) {
         depth_load = true;
         setup_render_ds = true;
         hw_render->depth_init = VK_ATTACHMENT_LOAD_OP_LOAD;
         hw_subpass->depth_initop = VK_ATTACHMENT_LOAD_OP_LOAD;

         assert(!ctx->ds_load_surface);
         ctx->ds_load_surface = int_ds_attach;
      } else if (int_ds_attach->load_op == VK_ATTACHMENT_LOAD_OP_CLEAR) {
         hw_subpass->depth_initop = VK_ATTACHMENT_LOAD_OP_CLEAR;
      }

      if (int_ds_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) {
         if (int_ds_attach->stencil_load_op == VK_ATTACHMENT_LOAD_OP_LOAD) {
            stencil_load = true;
            setup_render_ds = true;
            hw_render->stencil_init = VK_ATTACHMENT_LOAD_OP_LOAD;
         } else if (int_ds_attach->stencil_load_op ==
                    VK_ATTACHMENT_LOAD_OP_CLEAR) {
            hw_subpass->stencil_clear = true;
         }
      }

      /* If the depth is loaded then allocate external memory for the depth
       * attachment.
       */
      if (depth_load || stencil_load)
         pvr_mark_surface_alloc(ctx, int_ds_attach);

      if (setup_render_ds) {
         assert(hw_render->ds_attach_idx == VK_ATTACHMENT_UNUSED);
         hw_render->ds_attach_idx = int_ds_attach->attachment->index;
      }

      ctx->int_ds_attach = int_ds_attach;
   }

   /* Set up the initialization operations for subpasses. */
   hw_subpass->color_initops = vk_alloc(ctx->allocator,
                                        sizeof(hw_subpass->color_initops[0U]) *
                                           input_subpass->color_count,
                                        8,
                                        VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
   if (!hw_subpass->color_initops) {
      result = vk_error(NULL, VK_ERROR_OUT_OF_HOST_MEMORY);
      goto end_merge_subpass;
   }

   for (uint32_t i = 0U; i < input_subpass->color_count; i++) {
      const uint32_t attach_idx = input_subpass->color_attachments[i];
      struct pvr_render_int_attachment *int_attach;

      if (attach_idx == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[attach_idx];

      if (int_attach->first_use == -1) {
         hw_subpass->color_initops[i] = int_attach->load_op;

         /* If the attachment is loaded then off-chip memory must be
          * allocated for it.
          */
         if (int_attach->load_op == VK_ATTACHMENT_LOAD_OP_LOAD)
            pvr_mark_surface_alloc(ctx, int_attach);

         /* The attachment has been written so load the attachment the next
          * time it is referenced.
          */
         int_attach->load_op = VK_ATTACHMENT_LOAD_OP_LOAD;
      } else {
         hw_subpass->color_initops[i] = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
      }
   }

   /* Copy the destinations allocated for the color attachments. */
   for (uint32_t i = 0U; i < input_subpass->color_count; i++) {
      const uint32_t attach_idx = input_subpass->color_attachments[i];
      struct pvr_render_int_attachment *int_attach;
      struct pvr_renderpass_resource *attach_dst;

      if (attach_idx == VK_ATTACHMENT_UNUSED)
         continue;

      int_attach = &ctx->int_attach[attach_idx];
      attach_dst = &sp_dsts.color[i];

      if (int_attach->first_use == -1) {
         assert(int_attach->resource.type == USC_MRT_RESOURCE_TYPE_INVALID);
         assert(attach_dst->type != USC_MRT_RESOURCE_TYPE_INVALID);
         pvr_set_surface_resource(int_attach, attach_dst);

         /* If this attachment is being used for the first time then add it
          * to the active list.
          */
         pvr_make_surface_active(ctx,
                                 int_attach,
                                 hw_render->subpass_count - 1U);
      } else {
         assert(attach_dst->type == USC_MRT_RESOURCE_TYPE_INVALID);
      }
   }

   /* We can't directly read the on-chip depth so mark subpasses where the depth
    * is written to replicate the value into part of the color storage.
    */
   if (sp_depth.existing_ds_is_input) {
      result = pvr_enable_z_replicate(ctx,
                                      hw_render,
                                      sp_depth.existing_ds_attach,
                                      &sp_dsts.existing_zrep);
      if (result != VK_SUCCESS)
         goto end_merge_subpass;
   }

   if (sp_depth.incoming_ds_is_input) {
      if (input_subpass->depth_stencil_attachment !=
          sp_depth.existing_ds_attach) {
         result =
            pvr_enable_z_replicate(ctx,
                                   hw_render,
                                   input_subpass->depth_stencil_attachment,
                                   &sp_dsts.incoming_zrep);
         if (result != VK_SUCCESS)
            goto end_merge_subpass;
      } else {
         assert(pvr_equal_resources(&sp_dsts.existing_zrep,
                                    &sp_dsts.incoming_zrep));
      }
   }

   /* Copy the locations of color/input attachments to the output structure.
    * N.B. Need to do this after Z replication in case the replicated depth is
    * an input attachment for the incoming subpass.
    */
   result = pvr_copy_storage_details(ctx, hw_subpass, subpass);
   if (result != VK_SUCCESS)
      goto end_merge_subpass;

   if (subpass->z_replicate) {
      result = pvr_copy_z_replicate_details(ctx, hw_subpass, subpass);
      if (result != VK_SUCCESS)
         goto end_merge_subpass;
   }

   /* Copy the allocation at the subpass. This will then be updated if this was
    * last use of any attachment.
    */
   pvr_free_alloc(ctx, &ctx->alloc);
   ctx->alloc = alloc;

   /* Free information about subpass destinations. */
   if (sp_dsts.color)
      vk_free(ctx->allocator, sp_dsts.color);

   *hw_subpass_out = hw_subpass;

   return VK_SUCCESS;

end_merge_subpass:
   if (sp_dsts.color)
      vk_free(ctx->allocator, sp_dsts.color);

   pvr_free_alloc(ctx, &alloc);

   return result;
}

static void
pvr_dereference_color_output_list(struct pvr_renderpass_context *ctx,
                                  uint32_t subpass_num,
                                  struct pvr_render_subpass *subpass)
{
   for (uint32_t i = 0U; i < subpass->color_count; i++) {
      const uint32_t attach_idx = subpass->color_attachments[i];

      if (attach_idx != VK_ATTACHMENT_UNUSED)
         pvr_dereference_surface(ctx, attach_idx, subpass_num);
   }
}

static void pvr_dereference_surface_list(struct pvr_renderpass_context *ctx,
                                         uint32_t subpass_num,
                                         uint32_t *attachments,
                                         uint32_t count)
{
   for (uint32_t i = 0U; i < count; i++) {
      if (attachments[i] != VK_ATTACHMENT_UNUSED)
         pvr_dereference_surface(ctx, attachments[i], subpass_num);
   }
}

static VkResult pvr_schedule_subpass(const struct pvr_device *device,
                                     struct pvr_renderpass_context *ctx,
                                     uint32_t subpass_idx)
{
   struct pvr_renderpass_hwsetup_subpass *hw_subpass;
   struct pvr_renderpass_hwsetup_render *hw_render;
   struct pvr_render_int_subpass *int_subpass;
   struct pvr_render_subpass *subpass;
   uint32_t subpass_num;
   VkResult result;

   int_subpass = &ctx->int_subpasses[subpass_idx];
   subpass = int_subpass->subpass;

   result = pvr_merge_subpass(device, ctx, subpass, &hw_subpass);
   if (result != VK_SUCCESS)
      return result;

   hw_render = ctx->hw_render;
   subpass_num = hw_render->subpass_count - 1U;

   /* Record where the subpass was scheduled. */
   ctx->hw_setup->subpass_map[subpass_idx].render =
      ctx->hw_setup->render_count - 1U;
   ctx->hw_setup->subpass_map[subpass_idx].subpass = subpass_num;

   /* Check this subpass was the last use of any attachments. */
   pvr_dereference_color_output_list(ctx, subpass_num, subpass);
   pvr_dereference_surface_list(ctx,
                                subpass_num,
                                subpass->input_attachments,
                                subpass->input_count);
   if (subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED) {
      struct pvr_render_int_attachment *int_depth_attach =
         &ctx->int_attach[subpass->depth_stencil_attachment];

      assert(int_depth_attach->remaining_count > 0U);
      int_depth_attach->remaining_count--;

      if (int_depth_attach->remaining_count == 0U) {
         if (int_depth_attach->first_use != -1)
            int_depth_attach->last_use = subpass_num;

         if (int_depth_attach->z_replicate)
            pvr_free_surface_storage(ctx, int_depth_attach);
      }

      if (int_depth_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) {
         assert(int_depth_attach->stencil_remaining_count > 0U);
         int_depth_attach->stencil_remaining_count--;
      }

      /* The depth attachment has initialized data so load it from memory if it
       * is referenced again.
       */
      int_depth_attach->load_op = VK_ATTACHMENT_LOAD_OP_LOAD;
      int_depth_attach->stencil_load_op = VK_ATTACHMENT_LOAD_OP_LOAD;
   }

   /* Mark surfaces which have been the source or destination of an MSAA resolve
    * in the current render.
    */
   for (uint32_t i = 0U; i < subpass->color_count; i++) {
      struct pvr_render_int_attachment *resolve_src;
      struct pvr_render_int_attachment *resolve_dst;

      if (!subpass->resolve_attachments)
         break;

      if (subpass->resolve_attachments[i] == VK_ATTACHMENT_UNUSED)
         continue;

      assert(subpass->color_attachments[i] <
             (int32_t)ctx->pass->attachment_count);
      resolve_src = &ctx->int_attach[subpass->color_attachments[i]];

      assert(subpass->resolve_attachments[i] <
             (int32_t)ctx->pass->attachment_count);
      resolve_dst = &ctx->int_attach[subpass->resolve_attachments[i]];

      /* Mark the resolve source. */
      assert(resolve_src->last_resolve_src_render <
             (int32_t)(ctx->hw_setup->render_count - 1U));
      resolve_src->last_resolve_src_render = ctx->hw_setup->render_count - 1U;

      /* Mark the resolve destination. */
      assert(resolve_dst->last_resolve_dst_render <
             (int32_t)(ctx->hw_setup->render_count - 1U));
      resolve_dst->last_resolve_dst_render = ctx->hw_setup->render_count - 1U;

      /* If we can't down scale through the PBE then the src must be stored
       * for transfer down scale.
       */
      if (!resolve_src->is_pbe_downscalable &&
          resolve_src->last_read < (int32_t)ctx->pass->subpass_count) {
         resolve_src->last_read = (int32_t)ctx->pass->subpass_count;
         resolve_src->remaining_count++;
      }
   }

   /* For subpasses dependent on this subpass decrement the unscheduled
    * dependency count.
    */
   for (uint32_t i = 0U; i < int_subpass->out_subpass_count; i++) {
      struct pvr_render_int_subpass *int_dst_subpass =
         int_subpass->out_subpasses[i];

      assert(int_dst_subpass->in_subpass_count > 0U);
      int_dst_subpass->in_subpass_count--;
   }

   return VK_SUCCESS;
}

static uint32_t pvr_count_uses_in_list(uint32_t *attachments,
                                       uint32_t size,
                                       uint32_t attach_idx)
{
   uint32_t count = 0U;

   for (uint32_t i = 0U; i < size; i++) {
      if (attachments[i] == attach_idx)
         count++;
   }

   return count;
}

static uint32_t
pvr_count_uses_in_color_output_list(struct pvr_render_subpass *subpass,
                                    uint32_t attach_idx)
{
   uint32_t count = 0U;

   for (uint32_t i = 0U; i < subpass->color_count; i++) {
      if (subpass->color_attachments[i] == attach_idx) {
         count++;

         if (subpass->resolve_attachments &&
             subpass->resolve_attachments[i] != VK_ATTACHMENT_UNUSED)
            count++;
      }
   }

   return count;
}

void pvr_destroy_renderpass_hwsetup(const VkAllocationCallbacks *alloc,
                                    struct pvr_renderpass_hwsetup *hw_setup)
{
   for (uint32_t i = 0U; i < hw_setup->render_count; i++) {
      struct pvr_renderpass_hwsetup_render *hw_render = &hw_setup->renders[i];

      vk_free(alloc, hw_render->eot_surfaces);
      vk_free(alloc, hw_render->eot_setup.mrt_resources);
      vk_free(alloc, hw_render->init_setup.mrt_resources);
      vk_free(alloc, hw_render->color_init);

      for (uint32_t j = 0U; j < hw_render->subpass_count; j++) {
         struct pvr_renderpass_hwsetup_subpass *subpass =
            &hw_render->subpasses[j];

         vk_free(alloc, subpass->color_initops);
         vk_free(alloc, subpass->input_access);
         vk_free(alloc, subpass->setup.mrt_resources);
      }

      vk_free(alloc, hw_render->subpasses);
   }

   vk_free(alloc, hw_setup->renders);
   vk_free(alloc, hw_setup);
}

VkResult pvr_create_renderpass_hwsetup(
   struct pvr_device *device,
   const VkAllocationCallbacks *alloc,
   struct pvr_render_pass *pass,
   bool disable_merge,
   struct pvr_renderpass_hwsetup **const hw_setup_out)
{
   struct pvr_render_int_attachment *int_attachments;
   struct pvr_render_int_subpass *int_subpasses;
   struct pvr_renderpass_hw_map *subpass_map;
   struct pvr_renderpass_hwsetup *hw_setup;
   struct pvr_renderpass_context *ctx;
   bool *surface_allocate;
   VkResult result;

   VK_MULTIALLOC(ma);
   vk_multialloc_add(&ma, &hw_setup, __typeof__(*hw_setup), 1);
   vk_multialloc_add(&ma,
                     &surface_allocate,
                     __typeof__(*surface_allocate),
                     pass->attachment_count);
   vk_multialloc_add(&ma,
                     &subpass_map,
                     __typeof__(*subpass_map),
                     pass->subpass_count);

   if (!vk_multialloc_zalloc(&ma, alloc, VK_SYSTEM_ALLOCATION_SCOPE_OBJECT)) {
      return vk_error(device, VK_ERROR_OUT_OF_HOST_MEMORY);
   }

   hw_setup->surface_allocate = surface_allocate;
   hw_setup->subpass_map = subpass_map;

   VK_MULTIALLOC(ma_ctx);
   vk_multialloc_add(&ma_ctx, &ctx, __typeof__(*ctx), 1);
   vk_multialloc_add(&ma_ctx,
                     &int_attachments,
                     __typeof__(*int_attachments),
                     pass->attachment_count);
   vk_multialloc_add(&ma_ctx,
                     &int_subpasses,
                     __typeof__(*int_subpasses),
                     pass->subpass_count);

   if (!vk_multialloc_zalloc(&ma_ctx,
                             alloc,
                             VK_SYSTEM_ALLOCATION_SCOPE_COMMAND)) {
      return vk_error(device, VK_ERROR_OUT_OF_HOST_MEMORY);
   }

   ctx->pass = pass;
   ctx->hw_setup = hw_setup;
   ctx->int_attach = int_attachments;
   ctx->int_subpasses = int_subpasses;
   ctx->allocator = alloc;

   for (uint32_t i = 0U; i < pass->attachment_count; i++) {
      struct pvr_render_pass_attachment *attachment = &pass->attachments[i];
      struct pvr_render_int_attachment *int_attach = &ctx->int_attach[i];
      const uint32_t pixel_size =
         vk_format_get_blocksizebits(attachment->vk_format) / 32U;
      const uint32_t part_bits =
         vk_format_get_blocksizebits(attachment->vk_format) % 32U;

      int_attach->resource.type = USC_MRT_RESOURCE_TYPE_INVALID;
      int_attach->resource.intermediate_size =
         DIV_ROUND_UP(vk_format_get_blocksizebits(attachment->vk_format),
                      CHAR_BIT);
      int_attach->resource.mrt_desc.intermediate_size =
         int_attach->resource.intermediate_size;

      for (uint32_t j = 0U; j < pixel_size; j++)
         int_attach->resource.mrt_desc.valid_mask[j] = ~0;

      if (part_bits > 0U) {
         int_attach->resource.mrt_desc.valid_mask[pixel_size] =
            BITFIELD_MASK(part_bits);
      }

      int_attach->load_op = pass->attachments[i].load_op;
      int_attach->stencil_load_op = pass->attachments[i].stencil_load_op;
      int_attach->attachment = attachment;
      int_attach->first_use = -1;
      int_attach->last_use = -1;
      int_attach->last_read = -1;
      int_attach->mrt_idx = -1;
      int_attach->last_resolve_dst_render = -1;
      int_attach->last_resolve_src_render = -1;
      int_attach->z_replicate = false;
      int_attach->is_pbe_downscalable = attachment->is_pbe_downscalable;

      /* Count the number of references to this attachment in subpasses. */
      for (uint32_t j = 0U; j < pass->subpass_count; j++) {
         struct pvr_render_subpass *subpass = &pass->subpasses[j];
         const uint32_t color_output_uses =
            pvr_count_uses_in_color_output_list(subpass, i);
         const uint32_t input_attachment_uses =
            pvr_count_uses_in_list(subpass->input_attachments,
                                   subpass->input_count,
                                   i);

         if (color_output_uses != 0U || input_attachment_uses != 0U)
            int_attach->last_read = j;

         int_attach->remaining_count +=
            color_output_uses + input_attachment_uses;

         if ((uint32_t)subpass->depth_stencil_attachment == i)
            int_attach->remaining_count++;
      }

      if (int_attach->attachment->aspects & VK_IMAGE_ASPECT_STENCIL_BIT) {
         int_attach->stencil_remaining_count = int_attach->remaining_count;
         if (pass->attachments[i].stencil_store_op ==
             VK_ATTACHMENT_STORE_OP_STORE) {
            int_attach->stencil_remaining_count++;
         }
      }

      if (pass->attachments[i].store_op == VK_ATTACHMENT_STORE_OP_STORE) {
         int_attach->remaining_count++;
         int_attach->last_read = pass->subpass_count;
      }
   }

   for (uint32_t i = 0U; i < pass->subpass_count; i++) {
      struct pvr_render_int_subpass *int_subpass = &ctx->int_subpasses[i];

      int_subpass->subpass = &pass->subpasses[i];
      int_subpass->out_subpass_count = 0U;
      int_subpass->out_subpasses = NULL;
      int_subpass->in_subpass_count = int_subpass->subpass->dep_count;
   }

   /* For each dependency of a subpass create an edge in the opposite
    * direction.
    */
   for (uint32_t i = 0U; i < pass->subpass_count; i++) {
      struct pvr_render_int_subpass *int_subpass = &ctx->int_subpasses[i];

      for (uint32_t j = 0U; j < int_subpass->in_subpass_count; j++) {
         uint32_t src_idx = int_subpass->subpass->dep_list[j];
         struct pvr_render_int_subpass *int_src_subpass;
         struct pvr_render_int_subpass **out_subpasses;

         assert(src_idx < pass->subpass_count);

         int_src_subpass = &ctx->int_subpasses[src_idx];

         out_subpasses =
            vk_realloc(ctx->allocator,
                       int_src_subpass->out_subpasses,
                       sizeof(int_src_subpass->out_subpasses[0U]) *
                          (int_src_subpass->out_subpass_count + 1U),
                       8U,
                       VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
         if (!out_subpasses) {
            result = vk_error(device, VK_ERROR_OUT_OF_HOST_MEMORY);
            goto end_create_renderpass_hwsetup;
         }

         int_src_subpass->out_subpasses = out_subpasses;
         int_src_subpass->out_subpasses[int_src_subpass->out_subpass_count] =
            int_subpass;
         int_src_subpass->out_subpass_count++;
      }
   }

   pvr_reset_render(ctx);

   for (uint32_t i = 0U; i < pass->subpass_count; i++) {
      uint32_t j;

      /* Find a subpass with no unscheduled dependencies. */
      for (j = 0U; j < pass->subpass_count; j++) {
         struct pvr_render_int_subpass *int_subpass = &ctx->int_subpasses[j];

         if (int_subpass->subpass && int_subpass->in_subpass_count == 0U)
            break;
      }
      assert(j < pass->subpass_count);

      result = pvr_schedule_subpass(device, ctx, j);
      if (result != VK_SUCCESS)
         goto end_create_renderpass_hwsetup;

      if (disable_merge) {
         result = pvr_close_render(device, ctx);
         if (result != VK_SUCCESS)
            goto end_create_renderpass_hwsetup;
      }

      ctx->int_subpasses[j].subpass = NULL;
   }

   /* Finalise the last in-progress render. */
   result = pvr_close_render(device, ctx);

end_create_renderpass_hwsetup:
   if (result != VK_SUCCESS) {
      pvr_free_render(ctx);

      if (hw_setup) {
         pvr_destroy_renderpass_hwsetup(alloc, hw_setup);
         hw_setup = NULL;
      }
   }

   for (uint32_t i = 0U; i < pass->subpass_count; i++) {
      struct pvr_render_int_subpass *int_subpass = &ctx->int_subpasses[i];

      if (int_subpass->out_subpass_count > 0U)
         vk_free(alloc, int_subpass->out_subpasses);
   }

   vk_free(alloc, ctx);

   *hw_setup_out = hw_setup;

   return result;
}