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 <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index f47100ee40f..ca520f547a1 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -1846,6 +1846,7 @@ ir_function_signature::replace_parameters(exec_list *new_params)
 ir_function::ir_function(const char *name)
    : ir_instruction(ir_type_function)
 {
+   this->subroutine_index = -1;
    this->name = ralloc_strdup(this, name);
 }