glsl: Parse and propagate derivative_group to shader_info

NV_compute_shader_derivatives allow selecting between two possible
arrangements (quads and linear) when calculating derivatives and
certain subgroup operations in case of Vulkan.  So parse and propagate
those up to shader_info.h.

v2: Do not fail when ARB_compute_variable_group_size is being used,
    since we are still clarifying what is the right thing to do here.

Reviewed-by: Ian Romanick <[email protected]>

1 files changed, 40 insertions, 3 deletions

diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
index c6664e98ce3..5667fb73f1e 100644
--- a/src/compiler/glsl/linker.cpp
+++ b/src/compiler/glsl/linker.cpp
@@ -2170,9 +2170,9 @@ link_gs_inout_layout_qualifiers(struct gl_shader_program *prog,
 
 
 /**
- * Perform cross-validation of compute shader local_size_{x,y,z} layout
- * qualifiers for the attached compute shaders, and propagate them to the
- * linked CS and linked shader program.
+ * Perform cross-validation of compute shader local_size_{x,y,z} layout and
+ * derivative arrangement qualifiers for the attached compute shaders, and
+ * propagate them to the linked CS and linked shader program.
  */
 static void
 link_cs_input_layout_qualifiers(struct gl_shader_program *prog,
@@ -2191,6 +2191,8 @@ link_cs_input_layout_qualifiers(struct gl_shader_program *prog,
 
    gl_prog->info.cs.local_size_variable = false;
 
+   gl_prog->info.cs.derivative_group = DERIVATIVE_GROUP_NONE;
+
    /* From the ARB_compute_shader spec, in the section describing local size
     * declarations:
     *
@@ -2234,6 +2236,17 @@ link_cs_input_layout_qualifiers(struct gl_shader_program *prog,
          }
          gl_prog->info.cs.local_size_variable = true;
       }
+
+      enum gl_derivative_group group = shader->info.Comp.DerivativeGroup;
+      if (group != DERIVATIVE_GROUP_NONE) {
+         if (gl_prog->info.cs.derivative_group != DERIVATIVE_GROUP_NONE &&
+             gl_prog->info.cs.derivative_group != group) {
+            linker_error(prog, "compute shader defined with conflicting "
+                         "derivative groups\n");
+            return;
+         }
+         gl_prog->info.cs.derivative_group = group;
+      }
    }
 
    /* Just do the intrastage -> interstage propagation right now,
@@ -2246,6 +2259,30 @@ link_cs_input_layout_qualifiers(struct gl_shader_program *prog,
                          "local group size\n");
       return;
    }
+
+   if (gl_prog->info.cs.derivative_group == DERIVATIVE_GROUP_QUADS) {
+      if (gl_prog->info.cs.local_size[0] % 2 != 0) {
+         linker_error(prog, "derivative_group_quadsNV must be used with a "
+                      "local group size whose first dimension "
+                      "is a multiple of 2\n");
+         return;
+      }
+      if (gl_prog->info.cs.local_size[1] % 2 != 0) {
+         linker_error(prog, "derivative_group_quadsNV must be used with a local"
+                      "group size whose second dimension "
+                      "is a multiple of 2\n");
+         return;
+      }
+   } else if (gl_prog->info.cs.derivative_group == DERIVATIVE_GROUP_LINEAR) {
+      if ((gl_prog->info.cs.local_size[0] *
+           gl_prog->info.cs.local_size[1] *
+           gl_prog->info.cs.local_size[2]) % 4 != 0) {
+         linker_error(prog, "derivative_group_linearNV must be used with a "
+                      "local group size whose total number of invocations "
+                      "is a multiple of 4\n");
+         return;
+      }
+   }
 }
 
 /**