glsl: Eliminate ambiguity between function ins/outs and shader ins/outs

This patch replaces the three ir_variable_mode enums:

- ir_var_in
- ir_var_out
- ir_var_inout

with the following five:

- ir_var_shader_in
- ir_var_shader_out
- ir_var_function_in
- ir_var_function_out
- ir_var_function_inout

This eliminates a frustrating ambiguity: it used to be impossible to
tell whether an ir_var_{in,out} variable was a shader in/out or a
function in/out without seeing where the variable was declared in the
IR.  This complicated some optimization and lowering passes, and would
have become a problem for implementing varying structs.

In the lisp-style serialization of GLSL IR to strings performed by
ir_print_visitor.cpp and ir_reader.cpp, I've retained the names "in",
"out", and "inout" for function parameters, to avoid introducing code
churn to the src/glsl/builtins/ir/ directory.

Note: a couple of comments in the code seemed to indicate that we were
planning for a possible future in which geometry shaders could have
shader-scope inout variables.  Our GLSL grammar rejects shader-scope
inout variables, and I've been unable to find any evidence in the GLSL
standards documents (or extensions) that this will ever be allowed, so
I've eliminated these comments.

Reviewed-by: Carl Worth <[email protected]>
Reviewed-by: Jordan Justen <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>

7 files changed, 26 insertions, 30 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs_fp.cpp b/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
index 9ca082a0fc9..5f5f6a9ba76 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
@@ -610,7 +610,7 @@ fs_visitor::setup_fp_regs()
           */
          ir_variable *ir = new(mem_ctx) ir_variable(glsl_type::vec4_type,
                                                     "fp_input",
-                                                    ir_var_in);
+                                                    ir_var_shader_in);
          ir->location = i;
 
          this->current_annotation = ralloc_asprintf(ctx, "interpolate input %d",
diff --git a/src/mesa/drivers/dri/i965/brw_fs_vector_splitting.cpp b/src/mesa/drivers/dri/i965/brw_fs_vector_splitting.cpp
index 7a12e084ff8..b9487532c59 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_vector_splitting.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_vector_splitting.cpp
@@ -110,11 +110,13 @@ ir_vector_reference_visitor::get_variable_entry(ir_variable *var)
 
    switch (var->mode) {
    case ir_var_uniform:
-   case ir_var_in:
-   case ir_var_out:
-   case ir_var_inout:
+   case ir_var_shader_in:
+   case ir_var_shader_out:
+   case ir_var_function_in:
+   case ir_var_function_out:
+   case ir_var_function_inout:
       /* Can't split varyings or uniforms.  Function in/outs won't get split
-       * either, so don't care about the ambiguity.
+       * either.
        */
       return NULL;
    case ir_var_auto:
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 5885989e76e..ebb37fd3113 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -57,7 +57,7 @@ fs_visitor::visit(ir_variable *ir)
    if (variable_storage(ir))
       return;
 
-   if (ir->mode == ir_var_in) {
+   if (ir->mode == ir_var_shader_in) {
       if (!strcmp(ir->name, "gl_FragCoord")) {
 	 reg = emit_fragcoord_interpolation(ir);
       } else if (!strcmp(ir->name, "gl_FrontFacing")) {
@@ -68,7 +68,7 @@ fs_visitor::visit(ir_variable *ir)
       assert(reg);
       hash_table_insert(this->variable_ht, reg, ir);
       return;
-   } else if (ir->mode == ir_var_out) {
+   } else if (ir->mode == ir_var_shader_out) {
       reg = new(this->mem_ctx) fs_reg(this, ir->type);
 
       if (ir->index > 0) {
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index d9ff869f2da..cff04ba887c 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -905,11 +905,11 @@ vec4_visitor::visit(ir_variable *ir)
       return;
 
    switch (ir->mode) {
-   case ir_var_in:
+   case ir_var_shader_in:
       reg = new(mem_ctx) dst_reg(ATTR, ir->location);
       break;
 
-   case ir_var_out:
+   case ir_var_shader_out:
       reg = new(mem_ctx) dst_reg(this, ir->type);
 
       for (int i = 0; i < type_size(ir->type); i++) {
diff --git a/src/mesa/main/shader_query.cpp b/src/mesa/main/shader_query.cpp
index 27b1b8f5688..3014a97785d 100644
--- a/src/mesa/main/shader_query.cpp
+++ b/src/mesa/main/shader_query.cpp
@@ -106,7 +106,7 @@ _mesa_GetActiveAttrib(GLhandleARB program, GLuint desired_index,
       const ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
       if (var == NULL
-	  || var->mode != ir_var_in
+	  || var->mode != ir_var_shader_in
 	  || var->location == -1)
 	 continue;
 
@@ -169,7 +169,7 @@ _mesa_GetAttribLocation(GLhandleARB program, const GLcharARB * name)
        *     attribute, or if an error occurs, -1 will be returned."
        */
       if (var == NULL
-	  || var->mode != ir_var_in
+	  || var->mode != ir_var_shader_in
 	  || var->location == -1
 	  || var->location < VERT_ATTRIB_GENERIC0)
 	 continue;
@@ -197,7 +197,7 @@ _mesa_count_active_attribs(struct gl_shader_program *shProg)
       const ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
       if (var == NULL
-	  || var->mode != ir_var_in
+	  || var->mode != ir_var_shader_in
 	  || var->location == -1)
 	 continue;
 
@@ -223,7 +223,7 @@ _mesa_longest_attribute_name_length(struct gl_shader_program *shProg)
       const ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
       if (var == NULL
-	  || var->mode != ir_var_in
+	  || var->mode != ir_var_shader_in
 	  || var->location == -1)
 	 continue;
 
@@ -333,7 +333,7 @@ _mesa_GetFragDataIndex(GLuint program, const GLchar *name)
        *     attribute, or if an error occurs, -1 will be returned."
        */
       if (var == NULL
-          || var->mode != ir_var_out
+          || var->mode != ir_var_shader_out
           || var->location == -1
           || var->location < FRAG_RESULT_DATA0)
          continue;
@@ -389,7 +389,7 @@ _mesa_GetFragDataLocation(GLuint program, const GLchar *name)
        *     attribute, or if an error occurs, -1 will be returned."
        */
       if (var == NULL
-	  || var->mode != ir_var_out
+	  || var->mode != ir_var_shader_out
 	  || var->location == -1
 	  || var->location < FRAG_RESULT_DATA0)
 	 continue;
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index 0f7439b3b06..4723ec3578b 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -1529,21 +1529,18 @@ ir_to_mesa_visitor::visit(ir_dereference_variable *ir)
 					       var->location);
 	 this->variables.push_tail(entry);
 	 break;
-      case ir_var_in:
-      case ir_var_inout:
+      case ir_var_shader_in:
 	 /* The linker assigns locations for varyings and attributes,
 	  * including deprecated builtins (like gl_Color),
 	  * user-assigned generic attributes (glBindVertexLocation),
 	  * and user-defined varyings.
-	  *
-	  * FINISHME: We would hit this path for function arguments.  Fix!
 	  */
 	 assert(var->location != -1);
          entry = new(mem_ctx) variable_storage(var,
                                                PROGRAM_INPUT,
                                                var->location);
          break;
-      case ir_var_out:
+      case ir_var_shader_out:
 	 assert(var->location != -1);
          entry = new(mem_ctx) variable_storage(var,
                                                PROGRAM_OUTPUT,
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 1d96e905c1e..575636e6e57 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -2001,21 +2001,18 @@ glsl_to_tgsi_visitor::visit(ir_dereference_variable *ir)
         				       var->location);
          this->variables.push_tail(entry);
          break;
-      case ir_var_in:
-      case ir_var_inout:
+      case ir_var_shader_in:
          /* The linker assigns locations for varyings and attributes,
           * including deprecated builtins (like gl_Color), user-assign
           * generic attributes (glBindVertexLocation), and
           * user-defined varyings.
-          *
-          * FINISHME: We would hit this path for function arguments.  Fix!
           */
          assert(var->location != -1);
          entry = new(mem_ctx) variable_storage(var,
                                                PROGRAM_INPUT,
                                                var->location);
          break;
-      case ir_var_out:
+      case ir_var_shader_out:
          assert(var->location != -1);
          entry = new(mem_ctx) variable_storage(var,
                                                PROGRAM_OUTPUT,
@@ -2304,7 +2301,7 @@ glsl_to_tgsi_visitor::visit(ir_assignment *ir)
       assert(!ir->lhs->type->is_scalar() && !ir->lhs->type->is_vector());
       l.writemask = WRITEMASK_XYZW;
    } else if (ir->lhs->type->is_scalar() &&
-              ir->lhs->variable_referenced()->mode == ir_var_out) {
+              ir->lhs->variable_referenced()->mode == ir_var_shader_out) {
       /* FINISHME: This hack makes writing to gl_FragDepth, which lives in the
        * FINISHME: W component of fragment shader output zero, work correctly.
        */
@@ -2581,8 +2578,8 @@ glsl_to_tgsi_visitor::visit(ir_call *ir)
       ir_rvalue *param_rval = (ir_rvalue *)iter.get();
       ir_variable *param = (ir_variable *)sig_iter.get();
 
-      if (param->mode == ir_var_in ||
-          param->mode == ir_var_inout) {
+      if (param->mode == ir_var_function_in ||
+          param->mode == ir_var_function_inout) {
          variable_storage *storage = find_variable_storage(param);
          assert(storage);
 
@@ -2617,8 +2614,8 @@ glsl_to_tgsi_visitor::visit(ir_call *ir)
       ir_rvalue *param_rval = (ir_rvalue *)iter.get();
       ir_variable *param = (ir_variable *)sig_iter.get();
 
-      if (param->mode == ir_var_out ||
-          param->mode == ir_var_inout) {
+      if (param->mode == ir_var_function_out ||
+          param->mode == ir_var_function_inout) {
          variable_storage *storage = find_variable_storage(param);
          assert(storage);