[Mesa-dev] [PATCH] mesa: declare UniformBufferBindings as an array with a static size

[Marek Olšák]

Some Gallium drivers were crashing, because the array was not large enough.

v2: clamp the per-shader maximum in st/mesa, then sum them all up

NOTE: This is a candidate for the stable branches.
---
 src/mesa/main/bufferobj.c              |   10 ++--------
 src/mesa/main/config.h                 |    3 +++
 src/mesa/main/mtypes.h                 |    3 ++-
 src/mesa/state_tracker/st_extensions.c |    7 ++-----
 4 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 1566cb4..ffb67b9 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -619,13 +619,10 @@ _mesa_init_buffer_objects( struct gl_context *ctx )
    _mesa_reference_buffer_object(ctx, &ctx->CopyWriteBuffer,
                                  ctx->Shared->NullBufferObj);
 
-   ctx->UniformBufferBindings = calloc(ctx->Const.MaxUniformBufferBindings,
-				      sizeof(*ctx->UniformBufferBindings));
-
    _mesa_reference_buffer_object(ctx, &ctx->UniformBuffer,
 				 ctx->Shared->NullBufferObj);
 
-   for (i = 0; i < ctx->Const.MaxUniformBufferBindings; i++) {
+   for (i = 0; i < MAX_COMBINED_UNIFORM_BUFFERS; i++) {
       _mesa_reference_buffer_object(ctx,
 				    &ctx->UniformBufferBindings[i].BufferObject,
 				    ctx->Shared->NullBufferObj);
@@ -647,14 +644,11 @@ _mesa_free_buffer_objects( struct gl_context *ctx )
 
    _mesa_reference_buffer_object(ctx, &ctx->UniformBuffer, NULL);
 
-   for (i = 0; i < ctx->Const.MaxUniformBufferBindings; i++) {
+   for (i = 0; i < MAX_COMBINED_UNIFORM_BUFFERS; i++) {
       _mesa_reference_buffer_object(ctx,
 				    &ctx->UniformBufferBindings[i].BufferObject,
 				    NULL);
    }
-
-   free(ctx->UniformBufferBindings);
-   ctx->UniformBufferBindings = NULL;
 }
 
 static bool
diff --git a/src/mesa/main/config.h b/src/mesa/main/config.h
index ea87b75..4a4fdc9 100644
--- a/src/mesa/main/config.h
+++ b/src/mesa/main/config.h
@@ -168,6 +168,9 @@
 /*@{*/
 #define MAX_PROGRAM_LOCAL_PARAMS       4096
 #define MAX_UNIFORMS                   4096
+#define MAX_UNIFORM_BUFFERS            15 /* + 1 default uniform buffer */
+/* 6 is for vertex, hull, domain, geometry, fragment, and compute shader. */
+#define MAX_COMBINED_UNIFORM_BUFFERS   (MAX_UNIFORM_BUFFERS * 6)
 /*@}*/
 
 /**
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 817633c..96c06ae 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3527,7 +3527,8 @@ struct gl_context
     * associated with uniform blocks by glUniformBlockBinding()'s state in the
     * shader program.
     */
-   struct gl_uniform_buffer_binding *UniformBufferBindings;
+   struct gl_uniform_buffer_binding
+      UniformBufferBindings[MAX_COMBINED_UNIFORM_BUFFERS];
 
    /*@}*/
 
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 982e652..46acc87 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -197,6 +197,7 @@ void st_init_limits(struct st_context *st)
          screen->get_shader_param(screen, sh, PIPE_SHADER_CAP_MAX_CONST_BUFFERS);
       if (pc->MaxUniformBlocks)
          pc->MaxUniformBlocks -= 1; /* The first one is for ordinary uniforms. */
+      pc->MaxUniformBlocks = _min(pc->MaxUniformBlocks, MAX_UNIFORM_BUFFERS);
 
       pc->MaxCombinedUniformComponents = (pc->MaxUniformComponents +
                                           c->MaxUniformBlockSize / 4 *
@@ -279,15 +280,11 @@ void st_init_limits(struct st_context *st)
       st->ctx->Extensions.ARB_uniform_buffer_object = GL_TRUE;
       c->UniformBufferOffsetAlignment =
          screen->get_param(screen, PIPE_CAP_CONSTANT_BUFFER_OFFSET_ALIGNMENT);
-      /* FIXME: _mesa_init_buffer_objects() already has been, and
-       * ctx->UniformBufferBindings allocated, so unfortunately we can't just
-       * change MaxUniformBufferBindings a posteriori. */
-#if 0
       c->MaxCombinedUniformBlocks = c->MaxUniformBufferBindings =
          c->VertexProgram.MaxUniformBlocks +
          c->GeometryProgram.MaxUniformBlocks +
          c->FragmentProgram.MaxUniformBlocks;
-#endif
+      assert(c->MaxCombinedUniformBlocks <= MAX_COMBINED_UNIFORM_BUFFERS);
    }
 }
 
-- 
1.7.10.4