On 06/18/2014 02:51 AM, Iago Toral Quiroga wrote:
> Check if non-zero streams are used. Fail to link if emitting to unsupported
> streams or emitting to non-zero streams with output type other than GL_POINTS.
> ---
> src/glsl/linker.cpp | 148
> +++++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 134 insertions(+), 14 deletions(-)
>
> diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> index 0b6a716..f8ff138 100644
> --- a/src/glsl/linker.cpp
> +++ b/src/glsl/linker.cpp
> @@ -250,31 +250,100 @@ public:
> }
> };
>
> -
> /**
> - * Visitor that determines whether or not a shader uses ir_end_primitive.
> + * Visitor that determines the highest stream id to which a (geometry) shader
> + * emits vertices. It also checks whether End{Stream}Primitive is ever
> called.
> */
> -class find_end_primitive_visitor : public ir_hierarchical_visitor {
> +class find_emit_vertex_visitor : public ir_hierarchical_visitor {
> public:
> - find_end_primitive_visitor()
> - : found(false)
> + find_emit_vertex_visitor(int max_allowed)
> + : max_stream_allowed(max_allowed),
> + invalid_stream_id(0),
> + invalid_stream_id_from_emit_vertex(false),
> + end_primitive_found(false),
> + uses_non_zero_stream(false)
> {
> /* empty */
> }
>
> - virtual ir_visitor_status visit(ir_end_primitive *)
> + virtual ir_visitor_status visit_leave(ir_emit_vertex *ir)
> {
> - found = true;
> - return visit_stop;
> + int stream_id = ir->stream_id();
> +
> + if (stream_id < 0) {
> + invalid_stream_id = stream_id;
> + invalid_stream_id_from_emit_vertex = true;
> + return visit_stop;
> + }
> +
> + if (stream_id > max_stream_allowed) {
> + invalid_stream_id = stream_id;
> + invalid_stream_id_from_emit_vertex = true;
> + return visit_stop;
> + }
> +
> + if (stream_id != 0)
> + uses_non_zero_stream = true;
> +
> + return visit_continue;
> }
>
> - bool end_primitive_found()
> + virtual ir_visitor_status visit_leave(ir_end_primitive *ir)
> {
> - return found;
> + end_primitive_found = true;
> +
> + int stream_id = ir->stream_id();
> +
> + if (stream_id < 0) {
> + invalid_stream_id = stream_id;
> + invalid_stream_id_from_emit_vertex = false;
> + return visit_stop;
> + }
> +
> + if (stream_id > max_stream_allowed) {
> + invalid_stream_id = stream_id;
> + invalid_stream_id_from_emit_vertex = false;
> + return visit_stop;
> + }
> +
> + if (stream_id != 0)
> + uses_non_zero_stream = true;
> +
> + return visit_continue;
> + }
> +
> + bool error()
> + {
> + return invalid_stream_id != 0;
> + }
> +
> + const char *error_func()
> + {
> + return invalid_stream_id_from_emit_vertex ?
> + "EmitStreamVertex" : "EndStreamPrimitive";
> + }
> +
> + int error_stream()
> + {
> + return invalid_stream_id;
> + }
> +
> + bool uses_streams()
> + {
> + return uses_non_zero_stream;
> + }
> +
> + bool uses_end_primitive()
> + {
> + return end_primitive_found;
> }
>
> private:
> - bool found;
> + int max_stream_allowed;
> + int invalid_stream_id;
> + bool invalid_stream_id_from_emit_vertex;
> + bool end_primitive_found;
> + bool uses_non_zero_stream;
> };
>
> } /* anonymous namespace */
> @@ -551,10 +620,58 @@ validate_geometry_shader_executable(struct
> gl_shader_program *prog,
>
> analyze_clip_usage(prog, shader, &prog->Geom.UsesClipDistance,
> &prog->Geom.ClipDistanceArraySize);
> +}
> +
> +/**
> + * Check if geometry shaders emit to non-zero streams and do corresponding
> + * validations.
> + */
> +static void
> +validate_geometry_shader_emissions(struct gl_context *ctx,
> + struct gl_shader_program *prog)
> +{
> + if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) {
> + find_emit_vertex_visitor emit_vertex(ctx->Const.MaxVertexStreams - 1);
> + emit_vertex.run(prog->_LinkedShaders[MESA_SHADER_GEOMETRY]->ir);
> + if (emit_vertex.error()) {
> + linker_error(prog, "Invalid call %s(%d). Accepted values for the "
> + "stream parameter are in the range [0, %d].",
> + emit_vertex.error_func(),
> + emit_vertex.error_stream(),
> + ctx->Const.MaxVertexStreams - 1);
> + }
> + prog->Geom.UsesStreams = emit_vertex.uses_streams();
> + prog->Geom.UsesEndPrimitive = emit_vertex.uses_end_primitive();
>
> - find_end_primitive_visitor end_primitive;
> - end_primitive.run(shader->ir);
> - prog->Geom.UsesEndPrimitive = end_primitive.end_primitive_found();
> + /* From the ARB_gpu_shader5 spec:
> + *
> + * "Multiple vertex streams are supported only if the output
> primitive
> + * type is declared to be "points". A program will fail to link if
> it
> + * contains a geometry shader calling EmitStreamVertex() or
> + * EndStreamPrimitive() if its output primitive type is not
> "points".
> + *
> + * However, in the same spec:
> + *
> + * "The function EmitVertex() is equivalent to calling
> EmitStreamVertex()
> + * with <stream> set to zero."
> + *
> + * And:
> + *
> + * "The function EndPrimitive() is equivalent to calling
> + * EndStreamPrimitive() with <stream> set to zero."
> + *
> + * Since we can call EmitVertex() and EndPrimitive() when we output
> + * primitives other than points, calling EmitStreamVertex(0) or
> + * EmitEndPrimitive(0) should not produce errors. This it also what
> Nvidia
> + * does. Currently we only set prog->Geom.UsesStreams to TRUE when
> + * EmitStreamVertex() or EmitEndPrimitive() are called with a non-zero
> + * stream.
Does AMD also behave this way? If so, I can submit a spec bug to make
these explicitly legal. Otherwise, I think we should not allow it. We
probably ought to check Apple and the Intel Windows driver too...
> + */
> + if (prog->Geom.UsesStreams && prog->Geom.OutputType != GL_POINTS) {
> + linker_error(prog, "EmitStreamVertex(n) and EndStreamPrimitive(n) "
> + "with n>0 requires point output");
> + }
> + }
> }
>
>
> @@ -2556,6 +2673,9 @@ link_shaders(struct gl_context *ctx, struct
> gl_shader_program *prog)
> ;
> }
>
> + /* Check and validate stream emissions in geometry shaders */
> + validate_geometry_shader_emissions(ctx, prog);
> +
> /* Mark all generic shader inputs and outputs as unpaired. */
> for (unsigned i = MESA_SHADER_VERTEX; i <= MESA_SHADER_FRAGMENT; i++) {
> if (prog->_LinkedShaders[i] != NULL) {
>
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
