glsl: add subroutine index qualifier support

ARB_explicit_uniform_location allows the index for subroutine functions
to be explicitly set in the shader.

This patch reduces the restriction on the index qualifier in
validate_layout_qualifiers() to allow it to be applied to subroutines
and adds the new subroutine qualifier validation to ast_function::hir().

ast_fully_specified_type::has_qualifiers() is updated to allow the
index qualifier on subroutine functions when explicit uniform locations
is available.

A new check is added to ast_type_qualifier::merge_qualifier() to stop
multiple function qualifiers from being defied, before this patch this
would cause a segfault.

Finally a new variable is added to ir_function_signature to store the
index. This value is validated and the non explicit values assigned in
link_assign_subroutine_types().

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/mesa/main/shader_query.cpp b/src/mesa/main/shader_query.cpp
index 14f849e..79a91b5 100644
--- a/src/mesa/main/shader_query.cpp
+++ b/src/mesa/main/shader_query.cpp
@@ -661,6 +661,13 @@ _mesa_program_resource_index(struct gl_shader_program *shProg,
    switch (res->Type) {
    case GL_ATOMIC_COUNTER_BUFFER:
       return RESOURCE_ATC(res) - shProg->AtomicBuffers;
+   case GL_VERTEX_SUBROUTINE:
+   case GL_GEOMETRY_SUBROUTINE:
+   case GL_FRAGMENT_SUBROUTINE:
+   case GL_COMPUTE_SUBROUTINE:
+   case GL_TESS_CONTROL_SUBROUTINE:
+   case GL_TESS_EVALUATION_SUBROUTINE:
+      return RESOURCE_SUB(res)->index;
    case GL_UNIFORM_BLOCK:
    case GL_SHADER_STORAGE_BLOCK:
    case GL_TRANSFORM_FEEDBACK_VARYING: