glsl2: Remove the shader_in/shader_out tracking separate from var->mode.

I introduced this for ir_dead_code to distinguish function parameter
outvals from varying outputs.  Only, since ast_to_hir's
current_function is unset when setting up function parameters (they're
needed for making the function signature in the first place), all
function parameter outvals were marked as shader outputs anyway.  This
meant that an inlined function's cloned outval was marked as a shader
output and couldn't be dead-code eliminated.  Instead, since
ir_dead_code doesn't even look at function parameters, just use
var->mode.

The longest Mesa IR coming out of ir_to_mesa for Yo Frankie drops from
725 instructions to 636.

7 files changed, 17 insertions, 57 deletions

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 14c528075bb..292c7be6217 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1510,31 +1510,6 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
    else if (qual->uniform)
       var->mode = ir_var_uniform;
 
-   if (qual->uniform)
-      var->shader_in = true;
-
-   /* Any 'in' or 'inout' variables at global scope must be marked as being
-    * shader inputs.  Likewise, any 'out' or 'inout' variables at global scope
-    * must be marked as being shader outputs.
-    */
-   if (state->current_function == NULL) {
-      switch (var->mode) {
-      case ir_var_in:
-      case ir_var_uniform:
-	 var->shader_in = true;
-	 break;
-      case ir_var_out:
-	 var->shader_out = true;
-	 break;
-      case ir_var_inout:
-	 var->shader_in = true;
-	 var->shader_out = true;
-	 break;
-      default:
-	 break;
-      }
-   }
-
    if (qual->flat)
       var->interpolation = ir_var_flat;
    else if (qual->noperspective)
@@ -1702,11 +1677,19 @@ ast_declarator_list::hir(exec_list *instructions,
 				       & loc);
 
       if (this->type->qualifier.invariant) {
-	 if ((state->target == vertex_shader) && !var->shader_out) {
+	 if ((state->target == vertex_shader) && !(var->mode == ir_var_out ||
+						   var->mode == ir_var_inout)) {
+	    /* FINISHME: Note that this doesn't work for invariant on
+	     * a function signature outval
+	     */
 	    _mesa_glsl_error(& loc, state,
 			     "`%s' cannot be marked invariant, vertex shader "
 			     "outputs only\n", var->name);
-	 } else if ((state->target == fragment_shader) && !var->shader_in) {
+	 } else if ((state->target == fragment_shader) &&
+		    !(var->mode == ir_var_in || var->mode == ir_var_inout)) {
+	    /* FINISHME: Note that this doesn't work for invariant on
+	     * a function signature inval
+	     */
 	    _mesa_glsl_error(& loc, state,
 			     "`%s' cannot be marked invariant, fragment shader "
 			     "inputs only\n", var->name);
diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index c3bade8d549..dd059e470d5 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -902,7 +902,6 @@ ir_swizzle::variable_referenced()
 ir_variable::ir_variable(const struct glsl_type *type, const char *name,
 			 ir_variable_mode mode)
    : max_array_access(0), read_only(false), centroid(false), invariant(false),
-     shader_in(false), shader_out(false),
      mode(mode), interpolation(ir_var_smooth), array_lvalue(false)
 {
    this->ir_type = ir_type_variable;
@@ -922,9 +921,6 @@ ir_variable::ir_variable(const struct glsl_type *type, const char *name,
 const char *
 ir_variable::interpolation_string() const
 {
-   if (!this->shader_in && !this->shader_out)
-      return "";
-
    switch (this->interpolation) {
    case ir_var_smooth:        return "smooth";
    case ir_var_flat:          return "flat";
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 98789503e06..e61485813dc 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -194,10 +194,10 @@ public:
    /**
     * Get the string value for the interpolation qualifier
     *
-    * \return
-    * If none of \c shader_in or \c shader_out is set, an empty string will
-    * be returned.  Otherwise the string that would be used in a shader to
-    * specify \c mode will be returned.
+    * \return The string that would be used in a shader to specify \c
+    * mode will be returned.
+    *
+    * This function should only be used on a shader input or output variable.
     */
    const char *interpolation_string() const;
 
@@ -221,12 +221,6 @@ public:
    unsigned read_only:1;
    unsigned centroid:1;
    unsigned invariant:1;
-   /** If the variable is initialized outside of the scope of the shader */
-   unsigned shader_in:1;
-   /**
-    * If the variable value is later used outside of the scope of the shader.
-    */
-   unsigned shader_out:1;
 
    unsigned mode:3;
    unsigned interpolation:2;
diff --git a/src/glsl/ir_clone.cpp b/src/glsl/ir_clone.cpp
index 0e202164b32..a72609601ae 100644
--- a/src/glsl/ir_clone.cpp
+++ b/src/glsl/ir_clone.cpp
@@ -45,8 +45,6 @@ ir_variable::clone(void *mem_ctx, struct hash_table *ht) const
    var->read_only = this->read_only;
    var->centroid = this->centroid;
    var->invariant = this->invariant;
-   var->shader_in = this->shader_in;
-   var->shader_out = this->shader_out;
    var->interpolation = this->interpolation;
    var->array_lvalue = this->array_lvalue;
    var->location = this->location;
diff --git a/src/glsl/ir_dead_code.cpp b/src/glsl/ir_dead_code.cpp
index 2b971b7aaac..bf032f1dc21 100644
--- a/src/glsl/ir_dead_code.cpp
+++ b/src/glsl/ir_dead_code.cpp
@@ -68,7 +68,8 @@ do_dead_code(exec_list *instructions)
 	 /* Remove a single dead assignment to the variable we found.
 	  * Don't do so if it's a shader output, though.
 	  */
-	 if (!entry->var->shader_out) {
+	 if (entry->var->mode != ir_var_out &&
+	     entry->var->mode != ir_var_inout) {
 	    entry->assign->remove();
 	    progress = true;
 	 }
diff --git a/src/glsl/ir_variable.cpp b/src/glsl/ir_variable.cpp
index 478cefc5a6c..d9a16d42879 100644
--- a/src/glsl/ir_variable.cpp
+++ b/src/glsl/ir_variable.cpp
@@ -43,22 +43,12 @@ add_variable(const char *name, enum ir_variable_mode mode, int slot,
 
    switch (var->mode) {
    case ir_var_auto:
-      var->read_only = true;
-      break;
    case ir_var_in:
-      var->shader_in = true;
+   case ir_var_uniform:
       var->read_only = true;
       break;
    case ir_var_inout:
-      var->shader_in = true;
-      var->shader_out = true;
-      break;
    case ir_var_out:
-      var->shader_out = true;
-      break;
-   case ir_var_uniform:
-      var->shader_in = true;
-      var->read_only = true;
       break;
    default:
       assert(0);
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index b2953c67d11..94db57d6a52 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1124,7 +1124,6 @@ assign_varying_locations(struct gl_shader_program *prog,
        * by the following stage.
        */
       if (var->location == -1) {
-	 var->shader_out = false;
 	 var->mode = ir_var_auto;
       }
    }
@@ -1158,7 +1157,6 @@ assign_varying_locations(struct gl_shader_program *prog,
 	 /* An 'in' variable is only really a shader input if its
 	  * value is written by the previous stage.
 	  */
-	 var->shader_in = false;
 	 var->mode = ir_var_auto;
       }
    }