[Mesa-dev] [PATCH] swr: allocate all scratch space in one go for vertex buffers

[Ilia Mirkin]

Multiple buffers may reference client arrays. When this happens, we
might reach for scratch space multiple times, which could cause later
arrays to invalidate the pointers allocated for the earlier ones.

This fixes copyteximage 2D_ARRAY.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

It also fixes a bunch of random piglits. Also explains why it was always the
first thing that failed in copyteximage 2D_ARRAY -- the later ones had enough
scratch space to hold the whole thing.

 src/gallium/drivers/swr/swr_scratch.cpp |  4 ++--
 src/gallium/drivers/swr/swr_state.cpp   | 32 +++++++++++++++++++++++++++++---
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/src/gallium/drivers/swr/swr_scratch.cpp b/src/gallium/drivers/swr/swr_scratch.cpp
index 28eb2ac..2515c8b 100644
--- a/src/gallium/drivers/swr/swr_scratch.cpp
+++ b/src/gallium/drivers/swr/swr_scratch.cpp
@@ -35,7 +35,6 @@ swr_copy_to_scratch_space(struct swr_context *ctx,
 {
    void *ptr;
    assert(space);
-   assert(user_buffer);
    assert(size);
 
    if (size >= 2048) { /* XXX TODO create KNOB_ for this */
@@ -82,7 +81,8 @@ swr_copy_to_scratch_space(struct swr_context *ctx,
    }
 
    /* Copy user_buffer to scratch */
-   memcpy(ptr, user_buffer, size);
+   if (user_buffer)
+      memcpy(ptr, user_buffer, size);
 
    return ptr;
 }
diff --git a/src/gallium/drivers/swr/swr_state.cpp b/src/gallium/drivers/swr/swr_state.cpp
index f5f42ba..dcbe434 100644
--- a/src/gallium/drivers/swr/swr_state.cpp
+++ b/src/gallium/drivers/swr/swr_state.cpp
@@ -1039,14 +1039,39 @@ swr_update_derived(struct pipe_context *pipe,
    /* Set vertex & index buffers */
    /* (using draw info if called by swr_draw_vbo) */
    if (ctx->dirty & SWR_NEW_VERTEX) {
-      uint32_t size, pitch, max_vertex, partial_inbounds;
+      uint32_t size, pitch, max_vertex, partial_inbounds, scratch_total;
       const uint8_t *p_data;
+      uint8_t *scratch = NULL;
 
       /* If being called by swr_draw_vbo, copy draw details */
       struct pipe_draw_info info = {0};
       if (p_draw_info)
          info = *p_draw_info;
 
+      /* We must get all the scratch space in one go */
+      scratch_total = 0;
+      for (UINT i = 0; i < ctx->num_vertex_buffers; i++) {
+         struct pipe_vertex_buffer *vb = &ctx->vertex_buffer[i];
+
+         if (!vb->user_buffer)
+            continue;
+
+         if (vb->stride) {
+            size = (info.max_index - info.min_index + 1) * vb->stride;
+         } else {
+            /* pitch = 0, means constant value
+             * set size to 1 vertex */
+            size = ctx->velems->stream_pitch[i];
+         }
+
+         scratch_total += AlignUp(size, 4);
+      }
+
+      if (scratch_total) {
+         scratch = (uint8_t *)swr_copy_to_scratch_space(
+               ctx, &ctx->scratch->vertex_buffer, NULL, scratch_total);
+      }
+
       /* vertex buffers */
       SWR_VERTEX_BUFFER_STATE swrVertexBuffers[PIPE_MAX_ATTRIBS];
       for (UINT i = 0; i < ctx->num_vertex_buffers; i++) {
@@ -1083,8 +1108,9 @@ swr_update_derived(struct pipe_context *pipe,
             size = AlignUp(size, 4);
             const void *ptr = (const uint8_t *) vb->user_buffer
                + info.min_index * pitch;
-            ptr = swr_copy_to_scratch_space(
-               ctx, &ctx->scratch->vertex_buffer, ptr, size);
+            memcpy(scratch, ptr, size);
+            ptr = scratch;
+            scratch += size;
             p_data = (const uint8_t *)ptr - info.min_index * pitch;
          }
 
-- 
2.7.3