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]>

7 files changed, 83 insertions, 4 deletions

diff --git a/src/glsl/ast.h b/src/glsl/ast.h
index dfb036dde7e..3bea63ea0ed 100644
--- a/src/glsl/ast.h
+++ b/src/glsl/ast.h
@@ -772,7 +772,7 @@ public:
 class ast_fully_specified_type : public ast_node {
 public:
    virtual void print(void) const;
-   bool has_qualifiers() const;
+   bool has_qualifiers(_mesa_glsl_parse_state *state) const;
 
    ast_fully_specified_type() : qualifier(), specifier(NULL)
    {
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index db8c450b587..df6dd9b4759 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -2848,6 +2848,13 @@ apply_explicit_location(const struct ast_type_qualifier *qual,
          break;
       }
 
+      /* Check if index was set for the uniform instead of the function */
+      if (qual->flags.q.explicit_index && qual->flags.q.subroutine) {
+         _mesa_glsl_error(loc, state, "an index qualifier can only be "
+                          "used with subroutine functions");
+         return;
+      }
+
       unsigned qual_index;
       if (qual->flags.q.explicit_index &&
           process_qualifier_constant(state, loc, "index", qual->index,
@@ -3067,7 +3074,9 @@ apply_layout_qualifier_to_variable(const struct ast_type_qualifier *qual,
    if (qual->flags.q.explicit_location) {
       apply_explicit_location(qual, var, state, loc);
    } else if (qual->flags.q.explicit_index) {
-      _mesa_glsl_error(loc, state, "explicit index requires explicit location");
+      if (!qual->flags.q.subroutine_def)
+         _mesa_glsl_error(loc, state,
+                          "explicit index requires explicit location");
    }
 
    if (qual->flags.q.explicit_binding) {
@@ -5075,7 +5084,7 @@ ast_function::hir(exec_list *instructions,
    /* From page 56 (page 62 of the PDF) of the GLSL 1.30 spec:
     * "No qualifier is allowed on the return type of a function."
     */
-   if (this->return_type->has_qualifiers()) {
+   if (this->return_type->has_qualifiers(state)) {
       YYLTYPE loc = this->get_location();
       _mesa_glsl_error(& loc, state,
                        "function `%s' return type has qualifiers", name);
@@ -5207,6 +5216,27 @@ ast_function::hir(exec_list *instructions,
    if (this->return_type->qualifier.flags.q.subroutine_def) {
       int idx;
 
+      if (this->return_type->qualifier.flags.q.explicit_index) {
+         unsigned qual_index;
+         if (process_qualifier_constant(state, &loc, "index",
+                                        this->return_type->qualifier.index,
+                                        &qual_index)) {
+            if (!state->has_explicit_uniform_location()) {
+               _mesa_glsl_error(&loc, state, "subroutine index requires "
+                                "GL_ARB_explicit_uniform_location or "
+                                "GLSL 4.30");
+            } else if (qual_index >= MAX_SUBROUTINES) {
+               _mesa_glsl_error(&loc, state,
+                                "invalid subroutine index (%d) index must "
+                                "be a number between 0 and "
+                                "GL_MAX_SUBROUTINES - 1 (%d)", qual_index,
+                                MAX_SUBROUTINES - 1);
+            } else {
+               f->subroutine_index = qual_index;
+            }
+         }
+      }
+
       f->num_subroutine_types = this->return_type->qualifier.subroutine_list->declarations.length();
       f->subroutine_types = ralloc_array(state, const struct glsl_type *,
                                          f->num_subroutine_types);
diff --git a/src/glsl/ast_type.cpp b/src/glsl/ast_type.cpp
index 1e89a9e76b9..03ed4dcfa2a 100644
--- a/src/glsl/ast_type.cpp
+++ b/src/glsl/ast_type.cpp
@@ -38,13 +38,16 @@ ast_type_specifier::print(void) const
 }
 
 bool
-ast_fully_specified_type::has_qualifiers() const
+ast_fully_specified_type::has_qualifiers(_mesa_glsl_parse_state *state) const
 {
    /* 'subroutine' isnt a real qualifier. */
    ast_type_qualifier subroutine_only;
    subroutine_only.flags.i = 0;
    subroutine_only.flags.q.subroutine = 1;
    subroutine_only.flags.q.subroutine_def = 1;
+   if (state->has_explicit_uniform_location()) {
+      subroutine_only.flags.q.explicit_index = 1;
+   }
    return (this->qualifier.flags.i & ~subroutine_only.flags.i) != 0;
 }
 
@@ -176,6 +179,15 @@ ast_type_qualifier::merge_qualifier(YYLTYPE *loc,
       }
    }
 
+   if (q.flags.q.subroutine_def) {
+      if (this->flags.q.subroutine_def) {
+	 _mesa_glsl_error(loc, state,
+			  "conflicting subroutine qualifiers used");
+      } else {
+         this->subroutine_list = q.subroutine_list;
+      }
+   }
+
    if (q.flags.q.invocations) {
       if (this->invocations) {
          this->invocations->merge_qualifier(q.invocations);
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);
 }
 
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 39156e0e98c..e1109eec1d3 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -1171,6 +1171,8 @@ public:
     */
    int num_subroutine_types;
    const struct glsl_type **subroutine_types;
+
+   int subroutine_index;
 };
 
 inline const char *ir_function_signature::function_name() const
diff --git a/src/glsl/ir_clone.cpp b/src/glsl/ir_clone.cpp
index 4484cc9d8a7..bee60a241e4 100644
--- a/src/glsl/ir_clone.cpp
+++ b/src/glsl/ir_clone.cpp
@@ -270,6 +270,7 @@ ir_function::clone(void *mem_ctx, struct hash_table *ht) const
    ir_function *copy = new(mem_ctx) ir_function(this->name);
 
    copy->is_subroutine = this->is_subroutine;
+   copy->subroutine_index = this->subroutine_index;
    copy->num_subroutine_types = this->num_subroutine_types;
    copy->subroutine_types = ralloc_array(mem_ctx, const struct glsl_type *, copy->num_subroutine_types);
    for (int i = 0; i < copy->num_subroutine_types; i++)
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index db00f8febc6..331d9a28007 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -3864,10 +3864,43 @@ link_assign_subroutine_types(struct gl_shader_program *prog)
          sh->SubroutineFunctions[sh->NumSubroutineFunctions].types =
             ralloc_array(sh, const struct glsl_type *,
                          fn->num_subroutine_types);
+
+         /* From Section 4.4.4(Subroutine Function Layout Qualifiers) of the
+          * GLSL 4.5 spec:
+          *
+          *    "Each subroutine with an index qualifier in the shader must be
+          *    given a unique index, otherwise a compile or link error will be
+          *    generated."
+          */
+         for (unsigned j = 0; j < sh->NumSubroutineFunctions; j++) {
+            if (sh->SubroutineFunctions[j].index != -1 &&
+                sh->SubroutineFunctions[j].index == fn->subroutine_index) {
+               linker_error(prog, "each subroutine index qualifier in the "
+                            "shader must be unique\n");
+               return;
+            }
+         }
+         sh->SubroutineFunctions[sh->NumSubroutineFunctions].index =
+            fn->subroutine_index;
+
          for (int j = 0; j < fn->num_subroutine_types; j++)
             sh->SubroutineFunctions[sh->NumSubroutineFunctions].types[j] = fn->subroutine_types[j];
          sh->NumSubroutineFunctions++;
       }
+
+      /* Assign index for subroutines without an explicit index*/
+      int index = 0;
+      for (unsigned j = 0; j < sh->NumSubroutineFunctions; j++) {
+         while (sh->SubroutineFunctions[j].index == -1) {
+            for (unsigned k = 0; k < sh->NumSubroutineFunctions; k++) {
+               if (sh->SubroutineFunctions[k].index == index)
+                  break;
+               else if (k == sh->NumSubroutineFunctions - 1)
+                  sh->SubroutineFunctions[j].index = index;
+            }
+            index++;
+         }
+      }
    }
 }