If there is no Static Use of an input variable, the linker shouldn't
fail whenever there is no defined matching output variable in the
previous stage.
From page 47 (page 51 of the PDF) of the GLSL 4.60 v.5 spec:
" Only the input variables that are statically read need to be
written by the previous stage; it is allowed to have superfluous
declarations of input variables."
Now, we complete this exception whenever the input variable has an
explicit location. Previously, 18004c338f6 ("glsl: fail when a
shader's input var has not an equivalent out var in previous") took
care of the cases in which the input variable didn't have an explicit
location.
Additionally, likewise 1aa5738e666 ("glsl: relax input->output
validation for SSO programs"), avoid failing also for programs that
utilize GL_ARB_separate_shader_objects.
Cc: Timothy Arceri <tarc...@itsqueeze.com>
Cc: Iago Toral Quiroga <ito...@igalia.com>
Cc: Samuel Iglesias Gonsálvez <sigles...@igalia.com>
Cc: Tapani Pälli <tapani.pa...@intel.com>
Cc: Ian Romanick <ian.d.roman...@intel.com>
Signed-off-by: Andres Gomez <ago...@igalia.com>
---
src/compiler/glsl/link_varyings.cpp | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/src/compiler/glsl/link_varyings.cpp
b/src/compiler/glsl/link_varyings.cpp
index e5f7d3e322a..6cebc5b3c5a 100644
--- a/src/compiler/glsl/link_varyings.cpp
+++ b/src/compiler/glsl/link_varyings.cpp
@@ -808,8 +808,20 @@ cross_validate_outputs_to_inputs(struct gl_context *ctx,
output =
output_explicit_locations[idx][input->data.location_frac].var;
- if (output == NULL ||
- input->data.location != output->data.location) {
+ if (output == NULL) {
+ /* A linker failure should only happen when, for programs
+ * not using sso, there is no output declaration and there
+ * is Static Use of the declared input.
+ */
+ if (input->data.used && !prog->SeparateShader) {
+ linker_error(prog,
+ "%s shader input `%s' with explicit location
"
+ "has no matching output\n",
+
_mesa_shader_stage_to_string(consumer->Stage),
+ input->name);
+ break;
+ }
+ } else if (input->data.location != output->data.location) {
linker_error(prog,
"%s shader input `%s' with explicit location "
"has no matching output\n",
--
2.20.1
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