From: Iago Toral Quiroga Date: Mon, 16 Jun 2014 14:09:53 +0000 (+0200) Subject: glsl: Validate vertex emission in geometry shaders. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7589683c97442239295e700cbea17e82736f1f27;p=mesa.git glsl: Validate vertex emission in geometry shaders. 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. Reviewed-by: Chris Forbes --- diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp index 247c828d3d6..3036ebcb33e 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 set to zero." + * + * And: + * + * "The function EndPrimitive() is equivalent to calling + * EndStreamPrimitive() with 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. + */ + if (prog->Geom.UsesStreams && prog->Geom.OutputType != GL_POINTS) { + linker_error(prog, "EmitStreamVertex(n) and EndStreamPrimitive(n) " + "with n>0 requires point output"); + } + } } @@ -2558,6 +2675,9 @@ 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) {