From 76cfb472077dc83c892b4cddf79333341deaa7b5 Mon Sep 17 00:00:00 2001 From: Timothy Arceri Date: Mon, 25 Jan 2016 21:56:18 +1100 Subject: [PATCH] glsl: don't attempt to link empty program Previously an empty program would go through the entire link_shaders() function and we would have to be careful not to cause a segfault. In core profile also now set link_status to false by generating an error, it was previously set to true. From Section 7.3 (PROGRAM OBJECTS) of the OpenGL 4.5 spec: "Linking can fail for a variety of reasons as specified in the OpenGL Shading Language Specification, as well as any of the following reasons: - No shader objects are attached to program." V2: Only generate an error in core profile and add spec quote (Ian) V3: generate error in ES too, remove previous check which was only applying the rule to GL 4.5/ES 3.1 and above. My understand is that this spec change is clarifying previously undefined behaviour and therefore should be applied retrospectively. The ES CTS tests for this are in ES 2 I suspect it was passing because it would have generated an error for not having both a vertex and fragment shader. Reviewed-by: Kenneth Graunke --- src/compiler/glsl/linker.cpp | 46 ++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 23 deletions(-) diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp index f1ac53abb0a..31efb57b035 100644 --- a/src/compiler/glsl/linker.cpp +++ b/src/compiler/glsl/linker.cpp @@ -4106,15 +4106,34 @@ disable_varying_optimizations_for_sso(struct gl_shader_program *prog) void link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) { + prog->LinkStatus = true; /* All error paths will set this to false */ + prog->Validated = false; + prog->_Used = false; + + /* Section 7.3 (Program Objects) of the OpenGL 4.5 Core Profile spec says: + * + * "Linking can fail for a variety of reasons as specified in the + * OpenGL Shading Language Specification, as well as any of the + * following reasons: + * + * - No shader objects are attached to program." + * + * The Compatibility Profile specification does not list the error. In + * Compatibility Profile missing shader stages are replaced by + * fixed-function. This applies to the case where all stages are + * missing. + */ + if (prog->NumShaders == 0) { + if (ctx->API != API_OPENGL_COMPAT) + linker_error(prog, "no shaders attached to the program\n"); + return; + } + tfeedback_decl *tfeedback_decls = NULL; unsigned num_tfeedback_decls = prog->TransformFeedback.NumVarying; void *mem_ctx = ralloc_context(NULL); // temporary linker context - prog->LinkStatus = true; /* All error paths will set this to false */ - prog->Validated = false; - prog->_Used = false; - prog->ARB_fragment_coord_conventions_enable = false; /* Separate the shaders into groups based on their type. @@ -4163,25 +4182,6 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) prog->Version = max_version; prog->IsES = is_es_prog; - /* From OpenGL 4.5 Core specification (7.3 Program Objects): - * "Linking can fail for a variety of reasons as specified in the OpenGL - * Shading Language Specification, as well as any of the following - * reasons: - * - * * No shader objects are attached to program. - * - * ..." - * - * Same rule applies for OpenGL ES >= 3.1. - */ - - if (prog->NumShaders == 0 && - ((ctx->API == API_OPENGL_CORE && ctx->Version >= 45) || - (ctx->API == API_OPENGLES2 && ctx->Version >= 31))) { - linker_error(prog, "No shader objects are attached to program.\n"); - goto done; - } - /* Some shaders have to be linked with some other shaders present. */ if (num_shaders[MESA_SHADER_GEOMETRY] > 0 && -- 2.30.2