[Mesa-dev] [PATCH RFC 1/1] clover: Don't crash on NULL global buffer objects.

[Jan Vesely]

Specs say it's legal.
Fixes clones.xml gegl test.

---
Hi,

this patch is an attempt to support NULL buffer objects in clover.
It adds NULL handling to few places, and it's enough to get 'clones'
gegl test running.

The specs say: "If the argument is a buffer object, the arg_value
pointer can be NULL or point to a NULL value in which case a NULL
value will be used as the value for the argument declared as a
pointer to __global or __constant memory in the kernel."

I was considering using a special buffer instance to represent
NULL buffers but this seems more straightforward. Using 'pobj'
should take care of the latter part of the spec requirement too.

BZ: https://bugs.freedesktop.org/show_bug.cgi?id=73571#c2
ignore the first two comments I forgot I was testing some
additional patches.

Tom, I'm not sure I understand your comment. Does it mean that at
the moment it's possible that kernels receive NULL pointers
that point to valid buffers?

regards,
Jan

 src/gallium/drivers/r600/evergreen_compute.c      | 9 ++++++---
 src/gallium/state_trackers/clover/core/kernel.cpp | 4 ++--
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/gallium/drivers/r600/evergreen_compute.c b/src/gallium/drivers/r600/evergreen_compute.c
index a2db69b..f14b7c5 100644
--- a/src/gallium/drivers/r600/evergreen_compute.c
+++ b/src/gallium/drivers/r600/evergreen_compute.c
@@ -655,10 +655,13 @@ static void evergreen_set_global_binding(
 
 	for (int i = 0; i < n; i++)
 	{
-		assert(resources[i]->target == PIPE_BUFFER);
-		assert(resources[i]->bind & PIPE_BIND_GLOBAL);
+		if (resources[i]) {
+			assert(resources[i]->target == PIPE_BUFFER);
+			assert(resources[i]->bind & PIPE_BIND_GLOBAL);
 
-		*(handles[i]) = buffers[i]->chunk->start_in_dw * 4;
+			*(handles[i]) = buffers[i]->chunk->start_in_dw * 4;
+		} else
+			*(handles[i]) = NULL;
 	}
 
 	evergreen_set_rat(ctx->cs_shader_state.shader, 0, pool->bo, 0, pool->size_in_dw * 4);
diff --git a/src/gallium/state_trackers/clover/core/kernel.cpp b/src/gallium/state_trackers/clover/core/kernel.cpp
index ac57c71..412eac4 100644
--- a/src/gallium/state_trackers/clover/core/kernel.cpp
+++ b/src/gallium/state_trackers/clover/core/kernel.cpp
@@ -331,7 +331,7 @@ kernel::global_argument::set(size_t size, const void *value) {
    if (size != sizeof(cl_mem))
       throw error(CL_INVALID_ARG_SIZE);
 
-   buf = &obj<buffer>(*(cl_mem *)value);
+   buf = pobj<buffer>(value ? *(cl_mem *)value : NULL);
    _set = true;
 }
 
@@ -340,7 +340,7 @@ kernel::global_argument::bind(exec_context &ctx,
                               const module::argument &marg) {
    align(ctx.input, marg.target_align);
    ctx.g_handles.push_back(allocate(ctx.input, marg.target_size));
-   ctx.g_buffers.push_back(buf->resource(*ctx.q).pipe);
+   ctx.g_buffers.push_back(buf ? buf->resource(*ctx.q).pipe: NULL);
 }
 
 void
-- 
1.8.4.2