svgadump: Dump the new depth format names.
[mesa.git] / src / glsl / linker.cpp
index deb30d7fecf9534a787983e0e48801e777bb3307..195f58f29c6bb191aaa4d1e73a9080343a6071c7 100644 (file)
  *
  * \author Ian Romanick <ian.d.romanick@intel.com>
  */
-#include <cstdlib>
-#include <cstdio>
-#include <cstdarg>
-#include <climits>
 
-extern "C" {
-#include <talloc.h>
-}
-
-#include "main/compiler.h"
-#include "main/mtypes.h"
-#include "main/macros.h"
-#include "main/shaderobj.h"
+#include "main/core.h"
 #include "glsl_symbol_table.h"
 #include "ir.h"
 #include "program.h"
@@ -83,6 +72,10 @@ extern "C" {
 #include "linker.h"
 #include "ir_optimization.h"
 
+extern "C" {
+#include "main/shaderobj.h"
+}
+
 /**
  * Visitor that determines whether or not a variable is ever written.
  */
@@ -106,6 +99,27 @@ public:
       return visit_continue_with_parent;
    }
 
+   virtual ir_visitor_status visit_enter(ir_call *ir)
+   {
+      exec_list_iterator sig_iter = ir->get_callee()->parameters.iterator();
+      foreach_iter(exec_list_iterator, iter, *ir) {
+        ir_rvalue *param_rval = (ir_rvalue *)iter.get();
+        ir_variable *sig_param = (ir_variable *)sig_iter.get();
+
+        if (sig_param->mode == ir_var_out ||
+            sig_param->mode == ir_var_inout) {
+           ir_variable *var = param_rval->variable_referenced();
+           if (var && strcmp(name, var->name) == 0) {
+              found = true;
+              return visit_stop;
+           }
+        }
+        sig_iter.next();
+      }
+
+      return visit_continue_with_parent;
+   }
+
    bool variable_found()
    {
       return found;
@@ -150,14 +164,29 @@ private:
 
 
 void
-linker_error_printf(gl_shader_program *prog, const char *fmt, ...)
+linker_error(gl_shader_program *prog, const char *fmt, ...)
+{
+   va_list ap;
+
+   ralloc_strcat(&prog->InfoLog, "error: ");
+   va_start(ap, fmt);
+   ralloc_vasprintf_append(&prog->InfoLog, fmt, ap);
+   va_end(ap);
+
+   prog->LinkStatus = false;
+}
+
+
+void
+linker_warning(gl_shader_program *prog, const char *fmt, ...)
 {
    va_list ap;
 
-   prog->InfoLog = talloc_strdup_append(prog->InfoLog, "error: ");
+   ralloc_strcat(&prog->InfoLog, "error: ");
    va_start(ap, fmt);
-   prog->InfoLog = talloc_vasprintf_append(prog->InfoLog, fmt, ap);
+   ralloc_vasprintf_append(&prog->InfoLog, fmt, ap);
    va_end(ap);
+
 }
 
 
@@ -173,7 +202,7 @@ invalidate_variable_locations(gl_shader *sh, enum ir_variable_mode mode,
 
       /* Only assign locations for generic attributes / varyings / etc.
        */
-      if (var->location >= generic_base)
+      if ((var->location >= generic_base) && !var->explicit_location)
          var->location = -1;
    }
 }
@@ -229,11 +258,29 @@ validate_vertex_shader_executable(struct gl_shader_program *prog,
    find_assignment_visitor find("gl_Position");
    find.run(shader->ir);
    if (!find.variable_found()) {
-      linker_error_printf(prog,
-                         "vertex shader does not write to `gl_Position'\n");
+      linker_error(prog, "vertex shader does not write to `gl_Position'\n");
       return false;
    }
 
+   if (prog->Version >= 130) {
+      /* From section 7.1 (Vertex Shader Special Variables) of the
+       * GLSL 1.30 spec:
+       *
+       *   "It is an error for a shader to statically write both
+       *   gl_ClipVertex and gl_ClipDistance."
+       */
+      find_assignment_visitor clip_vertex("gl_ClipVertex");
+      find_assignment_visitor clip_distance("gl_ClipDistance");
+
+      clip_vertex.run(shader->ir);
+      clip_distance.run(shader->ir);
+      if (clip_vertex.variable_found() && clip_distance.variable_found()) {
+         linker_error(prog, "vertex shader writes to both `gl_ClipVertex' "
+                      "and `gl_ClipDistance'\n");
+         return false;
+      }
+   }
+
    return true;
 }
 
@@ -257,8 +304,8 @@ validate_fragment_shader_executable(struct gl_shader_program *prog,
    frag_data.run(shader->ir);
 
    if (frag_color.variable_found() && frag_data.variable_found()) {
-      linker_error_printf(prog,  "fragment shader writes to both "
-                         "`gl_FragColor' and `gl_FragData'\n");
+      linker_error(prog,  "fragment shader writes to both "
+                  "`gl_FragColor' and `gl_FragData'\n");
       return false;
    }
 
@@ -281,6 +328,7 @@ mode_string(const ir_variable *var)
    case ir_var_out:     return "shader output";
    case ir_var_inout:   return "shader inout";
 
+   case ir_var_const_in:
    case ir_var_temporary:
    default:
       assert(!"Should not get here.");
@@ -303,6 +351,9 @@ cross_validate_globals(struct gl_shader_program *prog,
     */
    glsl_symbol_table variables;
    for (unsigned i = 0; i < num_shaders; i++) {
+      if (shader_list[i] == NULL)
+        continue;
+
       foreach_list(node, shader_list[i]->ir) {
         ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
@@ -325,22 +376,76 @@ cross_validate_globals(struct gl_shader_program *prog,
         ir_variable *const existing = variables.get_variable(var->name);
         if (existing != NULL) {
            if (var->type != existing->type) {
-              linker_error_printf(prog, "%s `%s' declared as type "
-                                  "`%s' and type `%s'\n",
-                                  mode_string(var),
-                                  var->name, var->type->name,
-                                  existing->type->name);
-              return false;
+              /* Consider the types to be "the same" if both types are arrays
+               * of the same type and one of the arrays is implicitly sized.
+               * In addition, set the type of the linked variable to the
+               * explicitly sized array.
+               */
+              if (var->type->is_array()
+                  && existing->type->is_array()
+                  && (var->type->fields.array == existing->type->fields.array)
+                  && ((var->type->length == 0)
+                      || (existing->type->length == 0))) {
+                 if (var->type->length != 0) {
+                    existing->type = var->type;
+                 }
+              } else {
+                 linker_error(prog, "%s `%s' declared as type "
+                              "`%s' and type `%s'\n",
+                              mode_string(var),
+                              var->name, var->type->name,
+                              existing->type->name);
+                 return false;
+              }
            }
 
+           if (var->explicit_location) {
+              if (existing->explicit_location
+                  && (var->location != existing->location)) {
+                    linker_error(prog, "explicit locations for %s "
+                                 "`%s' have differing values\n",
+                                 mode_string(var), var->name);
+                    return false;
+              }
+
+              existing->location = var->location;
+              existing->explicit_location = true;
+           }
+
+        /* Validate layout qualifiers for gl_FragDepth.
+         *
+         * From the AMD/ARB_conservative_depth specs:
+         *    "If gl_FragDepth is redeclared in any fragment shader in
+         *    a program, it must be redeclared in all fragment shaders in that
+         *    program that have static assignments to gl_FragDepth. All
+         *    redeclarations of gl_FragDepth in all fragment shaders in
+         *    a single program must have the same set of qualifiers."
+         */
+        if (strcmp(var->name, "gl_FragDepth") == 0) {
+           bool layout_declared = var->depth_layout != ir_depth_layout_none;
+           bool layout_differs = var->depth_layout != existing->depth_layout;
+           if (layout_declared && layout_differs) {
+              linker_error(prog,
+                 "All redeclarations of gl_FragDepth in all fragment shaders "
+                 "in a single program must have the same set of qualifiers.");
+           }
+           if (var->used && layout_differs) {
+              linker_error(prog,
+                    "If gl_FragDepth is redeclared with a layout qualifier in"
+                    "any fragment shader, it must be redeclared with the same"
+                    "layout qualifier in all fragment shaders that have"
+                    "assignments to gl_FragDepth");
+           }
+        }
+
            /* FINISHME: Handle non-constant initializers.
             */
            if (var->constant_value != NULL) {
               if (existing->constant_value != NULL) {
                  if (!var->constant_value->has_value(existing->constant_value)) {
-                    linker_error_printf(prog, "initializers for %s "
-                                        "`%s' have differing values\n",
-                                        mode_string(var), var->name);
+                    linker_error(prog, "initializers for %s "
+                                 "`%s' have differing values\n",
+                                 mode_string(var), var->name);
                     return false;
                  }
               } else
@@ -357,10 +462,23 @@ cross_validate_globals(struct gl_shader_program *prog,
                   * FINISHME: will fail.
                   */
                  existing->constant_value =
-                    var->constant_value->clone(talloc_parent(existing), NULL);
+                    var->constant_value->clone(ralloc_parent(existing), NULL);
            }
+
+           if (existing->invariant != var->invariant) {
+              linker_error(prog, "declarations for %s `%s' have "
+                           "mismatching invariant qualifiers\n",
+                           mode_string(var), var->name);
+              return false;
+           }
+            if (existing->centroid != var->centroid) {
+               linker_error(prog, "declarations for %s `%s' have "
+                           "mismatching centroid qualifiers\n",
+                           mode_string(var), var->name);
+               return false;
+            }
         } else
-           variables.add_variable(var->name, var);
+           variables.add_variable(var);
       }
    }
 
@@ -375,7 +493,7 @@ bool
 cross_validate_uniforms(struct gl_shader_program *prog)
 {
    return cross_validate_globals(prog, prog->_LinkedShaders,
-                                prog->_NumLinkedShaders, true);
+                                MESA_SHADER_TYPES, true);
 }
 
 
@@ -402,7 +520,7 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
       if ((var == NULL) || (var->mode != ir_var_out))
         continue;
 
-      parameters.add_variable(var->name, var);
+      parameters.add_variable(var);
    }
 
 
@@ -424,53 +542,73 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
         /* Check that the types match between stages.
          */
         if (input->type != output->type) {
-           linker_error_printf(prog,
-                               "%s shader output `%s' delcared as "
-                               "type `%s', but %s shader input declared "
-                               "as type `%s'\n",
-                               producer_stage, output->name,
-                               output->type->name,
-                               consumer_stage, input->type->name);
-           return false;
+           /* There is a bit of a special case for gl_TexCoord.  This
+            * built-in is unsized by default.  Applications that variable
+            * access it must redeclare it with a size.  There is some
+            * language in the GLSL spec that implies the fragment shader
+            * and vertex shader do not have to agree on this size.  Other
+            * driver behave this way, and one or two applications seem to
+            * rely on it.
+            *
+            * Neither declaration needs to be modified here because the array
+            * sizes are fixed later when update_array_sizes is called.
+            *
+            * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
+            *
+            *     "Unlike user-defined varying variables, the built-in
+            *     varying variables don't have a strict one-to-one
+            *     correspondence between the vertex language and the
+            *     fragment language."
+            */
+           if (!output->type->is_array()
+               || (strncmp("gl_", output->name, 3) != 0)) {
+              linker_error(prog,
+                           "%s shader output `%s' declared as type `%s', "
+                           "but %s shader input declared as type `%s'\n",
+                           producer_stage, output->name,
+                           output->type->name,
+                           consumer_stage, input->type->name);
+              return false;
+           }
         }
 
         /* Check that all of the qualifiers match between stages.
          */
         if (input->centroid != output->centroid) {
-           linker_error_printf(prog,
-                               "%s shader output `%s' %s centroid qualifier, "
-                               "but %s shader input %s centroid qualifier\n",
-                               producer_stage,
-                               output->name,
-                               (output->centroid) ? "has" : "lacks",
-                               consumer_stage,
-                               (input->centroid) ? "has" : "lacks");
+           linker_error(prog,
+                        "%s shader output `%s' %s centroid qualifier, "
+                        "but %s shader input %s centroid qualifier\n",
+                        producer_stage,
+                        output->name,
+                        (output->centroid) ? "has" : "lacks",
+                        consumer_stage,
+                        (input->centroid) ? "has" : "lacks");
            return false;
         }
 
         if (input->invariant != output->invariant) {
-           linker_error_printf(prog,
-                               "%s shader output `%s' %s invariant qualifier, "
-                               "but %s shader input %s invariant qualifier\n",
-                               producer_stage,
-                               output->name,
-                               (output->invariant) ? "has" : "lacks",
-                               consumer_stage,
-                               (input->invariant) ? "has" : "lacks");
+           linker_error(prog,
+                        "%s shader output `%s' %s invariant qualifier, "
+                        "but %s shader input %s invariant qualifier\n",
+                        producer_stage,
+                        output->name,
+                        (output->invariant) ? "has" : "lacks",
+                        consumer_stage,
+                        (input->invariant) ? "has" : "lacks");
            return false;
         }
 
         if (input->interpolation != output->interpolation) {
-           linker_error_printf(prog,
-                               "%s shader output `%s' specifies %s "
-                               "interpolation qualifier, "
-                               "but %s shader input specifies %s "
-                               "interpolation qualifier\n",
-                               producer_stage,
-                               output->name,
-                               output->interpolation_string(),
-                               consumer_stage,
-                               input->interpolation_string());
+           linker_error(prog,
+                        "%s shader output `%s' specifies %s "
+                        "interpolation qualifier, "
+                        "but %s shader input specifies %s "
+                        "interpolation qualifier\n",
+                        producer_stage,
+                        output->name,
+                        output->interpolation_string(),
+                        consumer_stage,
+                        input->interpolation_string());
            return false;
         }
       }
@@ -494,9 +632,9 @@ populate_symbol_table(gl_shader *sh)
       ir_function *func;
 
       if ((func = inst->as_function()) != NULL) {
-        sh->symbols->add_function(func->name, func);
+        sh->symbols->add_function(func);
       } else if ((var = inst->as_variable()) != NULL) {
-        sh->symbols->add_variable(var->name, var);
+        sh->symbols->add_variable(var);
       }
    }
 }
@@ -553,7 +691,7 @@ remap_variables(ir_instruction *inst, struct gl_shader *target,
         else {
            ir_variable *copy = ir->var->clone(this->target, NULL);
 
-           this->symbols->add_variable(copy->name, copy);
+           this->symbols->add_variable(copy);
            this->instructions->push_head(copy);
            ir->var = copy;
         }
@@ -674,7 +812,8 @@ get_main_function_signature(gl_shader *sh)
  * shader is returned.
  */
 static struct gl_shader *
-link_intrastage_shaders(GLcontext *ctx,
+link_intrastage_shaders(void *mem_ctx,
+                       struct gl_context *ctx,
                        struct gl_shader_program *prog,
                        struct gl_shader **shader_list,
                        unsigned num_shaders)
@@ -708,17 +847,16 @@ link_intrastage_shaders(GLcontext *ctx,
               ir_function_signature *sig =
                  (ir_function_signature *) iter.get();
 
-              if (!sig->is_defined || sig->is_built_in)
+              if (!sig->is_defined || sig->is_builtin)
                  continue;
 
               ir_function_signature *other_sig =
                  other->exact_matching_signature(& sig->parameters);
 
               if ((other_sig != NULL) && other_sig->is_defined
-                  && !other_sig->is_built_in) {
-                 linker_error_printf(prog,
-                                     "function `%s' is multiply defined",
-                                     f->name);
+                  && !other_sig->is_builtin) {
+                 linker_error(prog, "function `%s' is multiply defined",
+                              f->name);
                  return NULL;
               }
            }
@@ -742,15 +880,15 @@ link_intrastage_shaders(GLcontext *ctx,
    }
 
    if (main == NULL) {
-      linker_error_printf(prog, "%s shader lacks `main'\n",
-                         (shader_list[0]->Type == GL_VERTEX_SHADER)
-                         ? "vertex" : "fragment");
+      linker_error(prog, "%s shader lacks `main'\n",
+                  (shader_list[0]->Type == GL_VERTEX_SHADER)
+                  ? "vertex" : "fragment");
       return NULL;
    }
 
-   gl_shader *const linked = ctx->Driver.NewShader(NULL, 0, main->Type);
+   gl_shader *linked = ctx->Driver.NewShader(NULL, 0, main->Type);
    linked->ir = new(linked) exec_list;
-   clone_ir_list(linked, linked->ir, main->ir);
+   clone_ir_list(mem_ctx, linked->ir, main->ir);
 
    populate_symbol_table(linked);
 
@@ -795,10 +933,47 @@ link_intrastage_shaders(GLcontext *ctx,
 
    assert(idx == num_linking_shaders);
 
-   link_function_calls(prog, linked, linking_shaders, num_linking_shaders);
+   if (!link_function_calls(prog, linked, linking_shaders,
+                           num_linking_shaders)) {
+      ctx->Driver.DeleteShader(ctx, linked);
+      linked = NULL;
+   }
 
    free(linking_shaders);
 
+#ifdef DEBUG
+   /* At this point linked should contain all of the linked IR, so
+    * validate it to make sure nothing went wrong.
+    */
+   if (linked)
+      validate_ir_tree(linked->ir);
+#endif
+
+   /* Make a pass over all variable declarations to ensure that arrays with
+    * unspecified sizes have a size specified.  The size is inferred from the
+    * max_array_access field.
+    */
+   if (linked != NULL) {
+      class array_sizing_visitor : public ir_hierarchical_visitor {
+      public:
+        virtual ir_visitor_status visit(ir_variable *var)
+        {
+           if (var->type->is_array() && (var->type->length == 0)) {
+              const glsl_type *type =
+                 glsl_type::get_array_instance(var->type->fields.array,
+                                               var->max_array_access + 1);
+
+              assert(type != NULL);
+              var->type = type;
+           }
+
+           return visit_continue;
+        }
+      } v;
+
+      v.run(linked->ir);
+   }
+
    return linked;
 }
 
@@ -825,18 +1000,26 @@ struct uniform_node {
 
  */
 static void
-update_uniform_array_sizes(struct gl_shader_program *prog)
+update_array_sizes(struct gl_shader_program *prog)
 {
-   for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
+   for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
+        if (prog->_LinkedShaders[i] == NULL)
+           continue;
+
       foreach_list(node, prog->_LinkedShaders[i]->ir) {
         ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
-        if ((var == NULL) || (var->mode != ir_var_uniform) ||
+        if ((var == NULL) || (var->mode != ir_var_uniform &&
+                              var->mode != ir_var_in &&
+                              var->mode != ir_var_out) ||
             !var->type->is_array())
            continue;
 
         unsigned int size = var->max_array_access;
-        for (unsigned j = 0; j < prog->_NumLinkedShaders; j++) {
+        for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) {
+              if (prog->_LinkedShaders[j] == NULL)
+                 continue;
+
            foreach_list(node2, prog->_LinkedShaders[j]->ir) {
               ir_variable *other_var = ((ir_instruction *) node2)->as_variable();
               if (!other_var)
@@ -848,7 +1031,21 @@ update_uniform_array_sizes(struct gl_shader_program *prog)
               }
            }
         }
+
         if (size + 1 != var->type->fields.array->length) {
+           /* If this is a built-in uniform (i.e., it's backed by some
+            * fixed-function state), adjust the number of state slots to
+            * match the new array size.  The number of slots per array entry
+            * is not known.  It seems safe to assume that the total number of
+            * slots is an integer multiple of the number of array elements.
+            * Determine the number of slots per array element by dividing by
+            * the old (total) size.
+            */
+           if (var->num_state_slots > 0) {
+              var->num_state_slots = (size + 1)
+                 * (var->num_state_slots / var->type->length);
+           }
+
            var->type = glsl_type::get_array_instance(var->type->fields.array,
                                                      size + 1);
            /* FINISHME: We should update the types of array
@@ -859,6 +1056,84 @@ update_uniform_array_sizes(struct gl_shader_program *prog)
    }
 }
 
+static void
+add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
+           const char *name, const glsl_type *type, GLenum shader_type,
+           unsigned *next_shader_pos, unsigned *total_uniforms)
+{
+   if (type->is_record()) {
+      for (unsigned int i = 0; i < type->length; i++) {
+        const glsl_type *field_type = type->fields.structure[i].type;
+        char *field_name = ralloc_asprintf(mem_ctx, "%s.%s", name,
+                                           type->fields.structure[i].name);
+
+        add_uniform(mem_ctx, uniforms, ht, field_name, field_type,
+                    shader_type, next_shader_pos, total_uniforms);
+      }
+   } else {
+      uniform_node *n = (uniform_node *) hash_table_find(ht, name);
+      unsigned int vec4_slots;
+      const glsl_type *array_elem_type = NULL;
+
+      if (type->is_array()) {
+        array_elem_type = type->fields.array;
+        /* Array of structures. */
+        if (array_elem_type->is_record()) {
+           for (unsigned int i = 0; i < type->length; i++) {
+              char *elem_name = ralloc_asprintf(mem_ctx, "%s[%d]", name, i);
+              add_uniform(mem_ctx, uniforms, ht, elem_name, array_elem_type,
+                          shader_type, next_shader_pos, total_uniforms);
+           }
+           return;
+        }
+      }
+
+      /* Fix the storage size of samplers at 1 vec4 each. Be sure to pad out
+       * vectors to vec4 slots.
+       */
+      if (type->is_array()) {
+        if (array_elem_type->is_sampler())
+           vec4_slots = type->length;
+        else
+           vec4_slots = type->length * array_elem_type->matrix_columns;
+      } else if (type->is_sampler()) {
+        vec4_slots = 1;
+      } else {
+        vec4_slots = type->matrix_columns;
+      }
+
+      if (n == NULL) {
+        n = (uniform_node *) calloc(1, sizeof(struct uniform_node));
+        n->u = (gl_uniform *) calloc(1, sizeof(struct gl_uniform));
+        n->slots = vec4_slots;
+
+        n->u->Name = strdup(name);
+        n->u->Type = type;
+        n->u->VertPos = -1;
+        n->u->FragPos = -1;
+        n->u->GeomPos = -1;
+        (*total_uniforms)++;
+
+        hash_table_insert(ht, n, name);
+        uniforms->push_tail(& n->link);
+      }
+
+      switch (shader_type) {
+      case GL_VERTEX_SHADER:
+        n->u->VertPos = *next_shader_pos;
+        break;
+      case GL_FRAGMENT_SHADER:
+        n->u->FragPos = *next_shader_pos;
+        break;
+      case GL_GEOMETRY_SHADER:
+        n->u->GeomPos = *next_shader_pos;
+        break;
+      }
+
+      (*next_shader_pos) += vec4_slots;
+   }
+}
+
 void
 assign_uniform_locations(struct gl_shader_program *prog)
 {
@@ -867,10 +1142,12 @@ assign_uniform_locations(struct gl_shader_program *prog)
    unsigned total_uniforms = 0;
    hash_table *ht = hash_table_ctor(32, hash_table_string_hash,
                                    hash_table_string_compare);
+   void *mem_ctx = ralloc_context(NULL);
 
-   update_uniform_array_sizes(prog);
+   for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
+      if (prog->_LinkedShaders[i] == NULL)
+        continue;
 
-   for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
       unsigned next_position = 0;
 
       foreach_list(node, prog->_LinkedShaders[i]->ir) {
@@ -879,54 +1156,23 @@ assign_uniform_locations(struct gl_shader_program *prog)
         if ((var == NULL) || (var->mode != ir_var_uniform))
            continue;
 
-        const unsigned vec4_slots = (var->component_slots() + 3) / 4;
-        if (vec4_slots == 0) {
-           /* If we've got a sampler or an aggregate of them, the size can
-            * end up zero.  Don't allocate any space.
+        if (strncmp(var->name, "gl_", 3) == 0) {
+           /* At the moment, we don't allocate uniform locations for
+            * builtin uniforms.  It's permitted by spec, and we'll
+            * likely switch to doing that at some point, but not yet.
             */
            continue;
         }
 
-        uniform_node *n = (uniform_node *) hash_table_find(ht, var->name);
-        if (n == NULL) {
-           n = (uniform_node *) calloc(1, sizeof(struct uniform_node));
-           n->u = (gl_uniform *) calloc(vec4_slots, sizeof(struct gl_uniform));
-           n->slots = vec4_slots;
-
-           n->u[0].Name = strdup(var->name);
-           for (unsigned j = 1; j < vec4_slots; j++)
-              n->u[j].Name = strdup(var->name);
-
-           hash_table_insert(ht, n, n->u[0].Name);
-           uniforms.push_tail(& n->link);
-           total_uniforms += vec4_slots;
-        }
-
-        if (var->constant_value != NULL)
-           for (unsigned j = 0; j < vec4_slots; j++)
-              n->u[j].Initialized = true;
-
         var->location = next_position;
-
-        for (unsigned j = 0; j < vec4_slots; j++) {
-           switch (prog->_LinkedShaders[i]->Type) {
-           case GL_VERTEX_SHADER:
-              n->u[j].VertPos = next_position;
-              break;
-           case GL_FRAGMENT_SHADER:
-              n->u[j].FragPos = next_position;
-              break;
-           case GL_GEOMETRY_SHADER:
-              /* FINISHME: Support geometry shaders. */
-              assert(prog->_LinkedShaders[i]->Type != GL_GEOMETRY_SHADER);
-              break;
-           }
-
-           next_position++;
-        }
+        add_uniform(mem_ctx, &uniforms, ht, var->name, var->type,
+                    prog->_LinkedShaders[i]->Type,
+                    &next_position, &total_uniforms);
       }
    }
 
+   ralloc_free(mem_ctx);
+
    gl_uniform_list *ul = (gl_uniform_list *)
       calloc(1, sizeof(gl_uniform_list));
 
@@ -942,8 +1188,8 @@ assign_uniform_locations(struct gl_shader_program *prog)
       next = (uniform_node *) node->link.next;
 
       node->link.remove();
-      memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform) * node->slots);
-      idx += node->slots;
+      memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform));
+      idx++;
 
       free(node->u);
       free(node);
@@ -956,7 +1202,7 @@ assign_uniform_locations(struct gl_shader_program *prog)
 
 
 /**
- * Find a contiguous set of available bits in a bitmask
+ * Find a contiguous set of available bits in a bitmask.
  *
  * \param used_mask     Bits representing used (1) and unused (0) locations
  * \param needed_count  Number of contiguous bits needed.
@@ -987,23 +1233,50 @@ find_available_slots(unsigned used_mask, unsigned needed_count)
 }
 
 
+/**
+ * Assign locations for either VS inputs for FS outputs
+ *
+ * \param prog          Shader program whose variables need locations assigned
+ * \param target_index  Selector for the program target to receive location
+ *                      assignmnets.  Must be either \c MESA_SHADER_VERTEX or
+ *                      \c MESA_SHADER_FRAGMENT.
+ * \param max_index     Maximum number of generic locations.  This corresponds
+ *                      to either the maximum number of draw buffers or the
+ *                      maximum number of generic attributes.
+ *
+ * \return
+ * If locations are successfully assigned, true is returned.  Otherwise an
+ * error is emitted to the shader link log and false is returned.
+ *
+ * \bug
+ * Locations set via \c glBindFragDataLocation are not currently supported.
+ * Only locations assigned automatically by the linker, explicitly set by a
+ * layout qualifier, or explicitly set by a built-in variable (e.g., \c
+ * gl_FragColor) are supported for fragment shaders.
+ */
 bool
-assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index)
+assign_attribute_or_color_locations(gl_shader_program *prog,
+                                   unsigned target_index,
+                                   unsigned max_index)
 {
-   /* Mark invalid attribute locations as being used.
+   /* Mark invalid locations as being used.
     */
-   unsigned used_locations = (max_attribute_index >= 32)
-      ? ~0 : ~((1 << max_attribute_index) - 1);
+   unsigned used_locations = (max_index >= 32)
+      ? ~0 : ~((1 << max_index) - 1);
+
+   assert((target_index == MESA_SHADER_VERTEX)
+         || (target_index == MESA_SHADER_FRAGMENT));
 
-   gl_shader *const sh = prog->_LinkedShaders[0];
-   assert(sh->Type == GL_VERTEX_SHADER);
+   gl_shader *const sh = prog->_LinkedShaders[target_index];
+   if (sh == NULL)
+      return true;
 
    /* Operate in a total of four passes.
     *
     * 1. Invalidate the location assignments for all vertex shader inputs.
     *
     * 2. Assign locations for inputs that have user-defined (via
-    *    glBindVertexAttribLocation) locatoins.
+    *    glBindVertexAttribLocation) locations.
     *
     * 3. Sort the attributes without assigned locations by number of slots
     *    required in decreasing order.  Fragmentation caused by attribute
@@ -1013,9 +1286,16 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
     * 4. Assign locations to any inputs without assigned locations.
     */
 
-   invalidate_variable_locations(sh, ir_var_in, VERT_ATTRIB_GENERIC0);
+   const int generic_base = (target_index == MESA_SHADER_VERTEX)
+      ? (int) VERT_ATTRIB_GENERIC0 : (int) FRAG_RESULT_DATA0;
+
+   const enum ir_variable_mode direction =
+      (target_index == MESA_SHADER_VERTEX) ? ir_var_in : ir_var_out;
+
 
-   if (prog->Attributes != NULL) {
+   invalidate_variable_locations(sh, direction, generic_base);
+
+   if ((target_index == MESA_SHADER_VERTEX) && (prog->Attributes != NULL)) {
       for (unsigned i = 0; i < prog->Attributes->NumParameters; i++) {
         ir_variable *const var =
            sh->symbols->get_variable(prog->Attributes->Parameters[i].Name);
@@ -1068,10 +1348,10 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
          * attribute overlaps any previously allocated bits.
          */
         if ((~(use_mask << attr) & used_locations) != used_locations) {
-           linker_error_printf(prog,
-                               "insufficient contiguous attribute locations "
-                               "available for vertex shader input `%s'",
-                               var->name);
+           linker_error(prog,
+                        "insufficient contiguous attribute locations "
+                        "available for vertex shader input `%s'",
+                        var->name);
            return false;
         }
 
@@ -1102,9 +1382,26 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
    foreach_list(node, sh->ir) {
       ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
-      if ((var == NULL) || (var->mode != ir_var_in))
+      if ((var == NULL) || (var->mode != (unsigned) direction))
         continue;
 
+      if (var->explicit_location) {
+        const unsigned slots = count_attribute_slots(var->type);
+        const unsigned use_mask = (1 << slots) - 1;
+        const int attr = var->location - generic_base;
+
+        if ((var->location >= (int)(max_index + generic_base))
+            || (var->location < 0)) {
+           linker_error(prog,
+                        "invalid explicit location %d specified for `%s'\n",
+                        (var->location < 0) ? var->location : attr,
+                        var->name);
+           return false;
+        } else if (var->location >= generic_base) {
+           used_locations |= (use_mask << attr);
+        }
+      }
+
       /* The location was explicitly assigned, nothing to do here.
        */
       if (var->location != -1)
@@ -1124,14 +1421,16 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
 
    qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare);
 
-   /* VERT_ATTRIB_GENERIC0 is a psdueo-alias for VERT_ATTRIB_POS.  It can only
-    * be explicitly assigned by via glBindAttribLocation.  Mark it as reserved
-    * to prevent it from being automatically allocated below.
-    */
-   find_deref_visitor find("gl_Vertex");
-   find.run(sh->ir);
-   if (find.variable_found())
-      used_locations |= (1 << 0);
+   if (target_index == MESA_SHADER_VERTEX) {
+      /* VERT_ATTRIB_GENERIC0 is a pseudo-alias for VERT_ATTRIB_POS.  It can
+       * only be explicitly assigned by via glBindAttribLocation.  Mark it as
+       * reserved to prevent it from being automatically allocated below.
+       */
+      find_deref_visitor find("gl_Vertex");
+      find.run(sh->ir);
+      if (find.variable_found())
+        used_locations |= (1 << 0);
+   }
 
    for (unsigned i = 0; i < num_attr; i++) {
       /* Mask representing the contiguous slots that will be used by this
@@ -1142,14 +1441,17 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
       int location = find_available_slots(used_locations, to_assign[i].slots);
 
       if (location < 0) {
-        linker_error_printf(prog,
-                            "insufficient contiguous attribute locations "
-                            "available for vertex shader input `%s'",
-                            to_assign[i].var->name);
+        const char *const string = (target_index == MESA_SHADER_VERTEX)
+           ? "vertex shader input" : "fragment shader output";
+
+        linker_error(prog,
+                     "insufficient contiguous attribute locations "
+                     "available for %s `%s'",
+                     string, to_assign[i].var->name);
         return false;
       }
 
-      to_assign[i].var->location = VERT_ATTRIB_GENERIC0 + location;
+      to_assign[i].var->location = generic_base + location;
       used_locations |= (use_mask << location);
    }
 
@@ -1158,19 +1460,20 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
 
 
 /**
- * Demote shader outputs that are not read to being just plain global variables
+ * Demote shader inputs and outputs that are not used in other stages
  */
 void
-demote_unread_shader_outputs(gl_shader *sh)
+demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
 {
    foreach_list(node, sh->ir) {
       ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
-      if ((var == NULL) || (var->mode != ir_var_out))
+      if ((var == NULL) || (var->mode != int(mode)))
         continue;
 
-      /* An 'out' variable is only really a shader output if its value is read
-       * by the following stage.
+      /* A shader 'in' or 'out' variable is only really an input or output if
+       * its value is used by other shader stages.  This will cause the variable
+       * to have a location assigned.
        */
       if (var->location == -1) {
         var->mode = ir_var_auto;
@@ -1179,8 +1482,9 @@ demote_unread_shader_outputs(gl_shader *sh)
 }
 
 
-void
-assign_varying_locations(struct gl_shader_program *prog,
+bool
+assign_varying_locations(struct gl_context *ctx,
+                        struct gl_shader_program *prog,
                         gl_shader *producer, gl_shader *consumer)
 {
    /* FINISHME: Set dynamically when geometry shader support is added. */
@@ -1216,18 +1520,27 @@ assign_varying_locations(struct gl_shader_program *prog,
 
       assert(input_var->location == -1);
 
-      /* FINISHME: Location assignment will need some changes when arrays,
-       * FINISHME: matrices, and structures are allowed as shader inputs /
-       * FINISHME: outputs.
-       */
       output_var->location = output_index;
       input_var->location = input_index;
 
-      output_index++;
-      input_index++;
+      /* FINISHME: Support for "varying" records in GLSL 1.50. */
+      assert(!output_var->type->is_record());
+
+      if (output_var->type->is_array()) {
+        const unsigned slots = output_var->type->length
+           * output_var->type->fields.array->matrix_columns;
+
+        output_index += slots;
+        input_index += slots;
+      } else {
+        const unsigned slots = output_var->type->matrix_columns;
+
+        output_index += slots;
+        input_index += slots;
+      }
    }
 
-   demote_unread_shader_outputs(producer);
+   unsigned varying_vectors = 0;
 
    foreach_list(node, consumer->ir) {
       ir_variable *const var = ((ir_instruction *) node)->as_variable();
@@ -1250,31 +1563,56 @@ assign_varying_locations(struct gl_shader_program *prog,
             * "glsl1-varying read but not written" in piglit.
             */
 
-           linker_error_printf(prog, "fragment shader varying %s not written "
-                               "by vertex shader\n.", var->name);
-           prog->LinkStatus = false;
+           linker_error(prog, "fragment shader varying %s not written "
+                        "by vertex shader\n.", var->name);
         }
 
         /* An 'in' variable is only really a shader input if its
          * value is written by the previous stage.
          */
         var->mode = ir_var_auto;
+      } else {
+        /* The packing rules are used for vertex shader inputs are also used
+         * for fragment shader inputs.
+         */
+        varying_vectors += count_attribute_slots(var->type);
+      }
+   }
+
+   if (ctx->API == API_OPENGLES2 || prog->Version == 100) {
+      if (varying_vectors > ctx->Const.MaxVarying) {
+        linker_error(prog, "shader uses too many varying vectors "
+                     "(%u > %u)\n",
+                     varying_vectors, ctx->Const.MaxVarying);
+        return false;
+      }
+   } else {
+      const unsigned float_components = varying_vectors * 4;
+      if (float_components > ctx->Const.MaxVarying * 4) {
+        linker_error(prog, "shader uses too many varying components "
+                     "(%u > %u)\n",
+                     float_components, ctx->Const.MaxVarying * 4);
+        return false;
       }
    }
+
+   return true;
 }
 
 
 void
-link_shaders(GLcontext *ctx, struct gl_shader_program *prog)
+link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
 {
+   void *mem_ctx = ralloc_context(NULL); // temporary linker context
+
    prog->LinkStatus = false;
    prog->Validated = false;
    prog->_Used = false;
 
    if (prog->InfoLog != NULL)
-      talloc_free(prog->InfoLog);
+      ralloc_free(prog->InfoLog);
 
-   prog->InfoLog = talloc_strdup(NULL, "");
+   prog->InfoLog = ralloc_strdup(NULL, "");
 
    /* Separate the shaders into groups based on their type.
     */
@@ -1313,49 +1651,54 @@ link_shaders(GLcontext *ctx, struct gl_shader_program *prog)
     * match shading language versions.  With GLSL 1.30 and later, the versions
     * of all shaders must match.
     */
-   assert(min_version >= 110);
+   assert(min_version >= 100);
    assert(max_version <= 130);
-   if ((max_version >= 130) && (min_version != max_version)) {
-      linker_error_printf(prog, "all shaders must use same shading "
-                         "language version\n");
+   if ((max_version >= 130 || min_version == 100)
+       && min_version != max_version) {
+      linker_error(prog, "all shaders must use same shading "
+                  "language version\n");
       goto done;
    }
 
    prog->Version = max_version;
 
-   for (unsigned int i = 0; i < prog->_NumLinkedShaders; i++) {
-      ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
+   for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) {
+      if (prog->_LinkedShaders[i] != NULL)
+        ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
+
+      prog->_LinkedShaders[i] = NULL;
    }
 
    /* Link all shaders for a particular stage and validate the result.
     */
-   prog->_NumLinkedShaders = 0;
    if (num_vert_shaders > 0) {
       gl_shader *const sh =
-        link_intrastage_shaders(ctx, prog, vert_shader_list, num_vert_shaders);
+        link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list,
+                                num_vert_shaders);
 
       if (sh == NULL)
         goto done;
 
       if (!validate_vertex_shader_executable(prog, sh))
-         goto done;
+        goto done;
 
-      prog->_LinkedShaders[prog->_NumLinkedShaders] = sh;
-      prog->_NumLinkedShaders++;
+      _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX],
+                            sh);
    }
 
    if (num_frag_shaders > 0) {
       gl_shader *const sh =
-        link_intrastage_shaders(ctx, prog, frag_shader_list, num_frag_shaders);
+        link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list,
+                                num_frag_shaders);
 
       if (sh == NULL)
         goto done;
 
       if (!validate_fragment_shader_executable(prog, sh))
-         goto done;
+        goto done;
 
-      prog->_LinkedShaders[prog->_NumLinkedShaders] = sh;
-      prog->_NumLinkedShaders++;
+      _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
+                            sh);
    }
 
    /* Here begins the inter-stage linking phase.  Some initial validation is
@@ -1363,14 +1706,26 @@ link_shaders(GLcontext *ctx, struct gl_shader_program *prog)
     * varyings.
     */
    if (cross_validate_uniforms(prog)) {
-      /* Validate the inputs of each stage with the output of the preceeding
+      unsigned prev;
+
+      for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
+        if (prog->_LinkedShaders[prev] != NULL)
+           break;
+      }
+
+      /* Validate the inputs of each stage with the output of the preceding
        * stage.
        */
-      for (unsigned i = 1; i < prog->_NumLinkedShaders; i++) {
+      for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
+        if (prog->_LinkedShaders[i] == NULL)
+           continue;
+
         if (!cross_validate_outputs_to_inputs(prog,
-                                              prog->_LinkedShaders[i - 1],
+                                              prog->_LinkedShaders[prev],
                                               prog->_LinkedShaders[i]))
            goto done;
+
+        prev = i;
       }
 
       prog->LinkStatus = true;
@@ -1380,33 +1735,97 @@ link_shaders(GLcontext *ctx, struct gl_shader_program *prog)
     * uniforms, and varyings.  Later optimization could possibly make
     * some of that unused.
     */
-   for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
-      while (do_common_optimization(prog->_LinkedShaders[i]->ir, true))
+   for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
+      if (prog->_LinkedShaders[i] == NULL)
+        continue;
+
+      detect_recursion_linked(prog, prog->_LinkedShaders[i]->ir);
+      if (!prog->LinkStatus)
+        goto done;
+
+      while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, 32))
         ;
    }
 
+   update_array_sizes(prog);
+
    assign_uniform_locations(prog);
 
-   if (prog->_LinkedShaders[0]->Type == GL_VERTEX_SHADER) {
-      /* FINISHME: The value of the max_attribute_index parameter is
-       * FINISHME: implementation dependent based on the value of
-       * FINISHME: GL_MAX_VERTEX_ATTRIBS.  GL_MAX_VERTEX_ATTRIBS must be
-       * FINISHME: at least 16, so hardcode 16 for now.
-       */
-      if (!assign_attribute_locations(prog, 16))
+   /* FINISHME: The value of the max_attribute_index parameter is
+    * FINISHME: implementation dependent based on the value of
+    * FINISHME: GL_MAX_VERTEX_ATTRIBS.  GL_MAX_VERTEX_ATTRIBS must be
+    * FINISHME: at least 16, so hardcode 16 for now.
+    */
+   if (!assign_attribute_or_color_locations(prog, MESA_SHADER_VERTEX, 16)) {
+      goto done;
+   }
+
+   if (!assign_attribute_or_color_locations(prog, MESA_SHADER_FRAGMENT, ctx->Const.MaxDrawBuffers)) {
+      goto done;
+   }
+
+   unsigned prev;
+   for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
+      if (prog->_LinkedShaders[prev] != NULL)
+        break;
+   }
+
+   for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
+      if (prog->_LinkedShaders[i] == NULL)
+        continue;
+
+      if (!assign_varying_locations(ctx, prog,
+                                   prog->_LinkedShaders[prev],
+                                   prog->_LinkedShaders[i])) {
         goto done;
+      }
+
+      prev = i;
+   }
+
+   if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
+      demote_shader_inputs_and_outputs(prog->_LinkedShaders[MESA_SHADER_VERTEX],
+                                      ir_var_out);
+   }
 
-      if (prog->_NumLinkedShaders == 1)
-        demote_unread_shader_outputs(prog->_LinkedShaders[0]);
+   if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) {
+      gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_GEOMETRY];
+
+      demote_shader_inputs_and_outputs(sh, ir_var_in);
+      demote_shader_inputs_and_outputs(sh, ir_var_inout);
+      demote_shader_inputs_and_outputs(sh, ir_var_out);
+   }
+
+   if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) {
+      gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
+
+      demote_shader_inputs_and_outputs(sh, ir_var_in);
    }
 
-   for (unsigned i = 1; i < prog->_NumLinkedShaders; i++)
-      assign_varying_locations(prog,
-                              prog->_LinkedShaders[i - 1],
-                              prog->_LinkedShaders[i]);
+   /* OpenGL ES requires that a vertex shader and a fragment shader both be
+    * present in a linked program.  By checking for use of shading language
+    * version 1.00, we also catch the GL_ARB_ES2_compatibility case.
+    */
+   if (ctx->API == API_OPENGLES2 || prog->Version == 100) {
+      if (prog->_LinkedShaders[MESA_SHADER_VERTEX] == NULL) {
+        linker_error(prog, "program lacks a vertex shader\n");
+      } else if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL) {
+        linker_error(prog, "program lacks a fragment shader\n");
+      }
+   }
 
    /* FINISHME: Assign fragment shader output locations. */
 
 done:
    free(vert_shader_list);
+
+   for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
+      if (prog->_LinkedShaders[i] == NULL)
+        continue;
+
+      /* Retain any live IR, but trash the rest. */
+      reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir);
+   }
+
+   ralloc_free(mem_ctx);
 }