The existing code was very hard to follow and has been the source
of at least 3 bugs in the past year.
The existing code also has a bug for SSO where if we have a
multi-stage SSO for example a tes -> gs program, if we try to use
transform feedback with gs the existing code would look for the
transform feedback varyings in the tes stage and fail as it can't
find them.
V2: Add more code comments, always try to remove unused inputs
to the first stage.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
We really just needed to skip the existing ES < 3.1 check if we have
a compute shader, all other scenarios are already covered.
* No shaders is a link error.
* Geom or Tess without Vertex is a link error which means we always
require a Vertex shader and hence a Fragment shader.
* Finally a Compute shader linked with any other stage is a link error.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
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 <kenneth@whitecape.org>
The builtin function shader is part of the builtin state, released
when glReleaseShaderCompiler is called. We must ensure that the
builtins have been (re)initialized before attempting to link with the
builtin shader.
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>
Tested-by: Rob Herring <robh@kernel.org>
Cc: mesa-stable@lists.freedesktop.org
