svgadump: Dump the new depth format names.
[mesa.git] / src / glsl / linker.cpp
index c906d7442127dadb9c2f073134ea01a09aeab042..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/core.h"
 #include "glsl_symbol_table.h"
@@ -172,14 +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);
+
 }
 
 
@@ -251,11 +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;
 }
 
@@ -279,8 +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;
    }
 
@@ -303,6 +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.");
@@ -360,18 +386,15 @@ cross_validate_globals(struct gl_shader_program *prog,
                   && (var->type->fields.array == existing->type->fields.array)
                   && ((var->type->length == 0)
                       || (existing->type->length == 0))) {
-                 if (existing->type->length == 0) {
+                 if (var->type->length != 0) {
                     existing->type = var->type;
-                    existing->max_array_access =
-                       MAX2(existing->max_array_access,
-                            var->max_array_access);
                  }
               } else {
-                 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);
+                 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;
               }
            }
@@ -379,9 +402,9 @@ cross_validate_globals(struct gl_shader_program *prog,
            if (var->explicit_location) {
               if (existing->explicit_location
                   && (var->location != existing->location)) {
-                    linker_error_printf(prog, "explicit locations for %s "
-                                        "`%s' have differing values\n",
-                                        mode_string(var), var->name);
+                    linker_error(prog, "explicit locations for %s "
+                                 "`%s' have differing values\n",
+                                 mode_string(var), var->name);
                     return false;
               }
 
@@ -389,14 +412,40 @@ cross_validate_globals(struct gl_shader_program *prog,
               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
@@ -413,19 +462,19 @@ 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_printf(prog, "declarations for %s `%s' have "
-                                  "mismatching invariant qualifiers\n",
-                                  mode_string(var), var->name);
+              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_printf(prog, "declarations for %s `%s' have "
-                                   "mismatching centroid qualifiers\n",
-                                   mode_string(var), var->name);
+               linker_error(prog, "declarations for %s `%s' have "
+                           "mismatching centroid qualifiers\n",
+                           mode_string(var), var->name);
                return false;
             }
         } else
@@ -494,7 +543,7 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
          */
         if (input->type != output->type) {
            /* There is a bit of a special case for gl_TexCoord.  This
-            * built-in is unsized by default.  Appliations that variable
+            * 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
@@ -513,13 +562,12 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
             */
            if (!output->type->is_array()
                || (strncmp("gl_", output->name, 3) != 0)) {
-              linker_error_printf(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);
+              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;
            }
         }
@@ -527,40 +575,40 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
         /* 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;
         }
       }
@@ -807,9 +855,8 @@ link_intrastage_shaders(void *mem_ctx,
 
               if ((other_sig != NULL) && other_sig->is_defined
                   && !other_sig->is_builtin) {
-                 linker_error_printf(prog,
-                                     "function `%s' is multiply defined",
-                                     f->name);
+                 linker_error(prog, "function `%s' is multiply defined",
+                              f->name);
                  return NULL;
               }
            }
@@ -833,9 +880,9 @@ link_intrastage_shaders(void *mem_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;
    }
 
@@ -894,30 +941,37 @@ link_intrastage_shaders(void *mem_ctx,
 
    free(linking_shaders);
 
-   /* Make a pass over all global variables to ensure that arrays with
+#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) {
-      foreach_list(node, linked->ir) {
-        ir_variable *const var = ((ir_instruction *) node)->as_variable();
-
-        if (var == NULL)
-           continue;
-
-        if ((var->mode != ir_var_auto) && (var->mode != ir_var_temporary))
-           continue;
-
-        if (!var->type->is_array() || (var->type->length != 0))
-           continue;
+      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;
+           }
 
-        const glsl_type *type =
-           glsl_type::get_array_instance(var->type->fields.array,
-                                         var->max_array_access);
+           return visit_continue;
+        }
+      } v;
 
-        assert(type != NULL);
-        var->type = type;
-      }
+      v.run(linked->ir);
    }
 
    return linked;
@@ -979,6 +1033,19 @@ update_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
@@ -997,7 +1064,7 @@ add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
    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 = talloc_asprintf(mem_ctx, "%s.%s", name,
+        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,
@@ -1013,7 +1080,7 @@ add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
         /* Array of structures. */
         if (array_elem_type->is_record()) {
            for (unsigned int i = 0; i < type->length; i++) {
-              char *elem_name = talloc_asprintf(mem_ctx, "%s[%d]", name, 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);
            }
@@ -1075,7 +1142,7 @@ 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 = talloc_new(NULL);
+   void *mem_ctx = ralloc_context(NULL);
 
    for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
       if (prog->_LinkedShaders[i] == NULL)
@@ -1104,7 +1171,7 @@ assign_uniform_locations(struct gl_shader_program *prog)
       }
    }
 
-   talloc_free(mem_ctx);
+   ralloc_free(mem_ctx);
 
    gl_uniform_list *ul = (gl_uniform_list *)
       calloc(1, sizeof(gl_uniform_list));
@@ -1135,7 +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.
@@ -1166,23 +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
@@ -1192,9 +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;
+
+
+   invalidate_variable_locations(sh, direction, generic_base);
 
-   if (prog->Attributes != NULL) {
+   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);
@@ -1247,10 +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;
         }
 
@@ -1281,23 +1382,22 @@ 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 - VERT_ATTRIB_GENERIC0;
+        const int attr = var->location - generic_base;
 
-        if ((var->location >= (int)(max_attribute_index + VERT_ATTRIB_GENERIC0))
+        if ((var->location >= (int)(max_index + generic_base))
             || (var->location < 0)) {
-           linker_error_printf(prog,
-                               "invalid explicit location %d specified for "
-                               "`%s'\n",
-                               (var->location < 0) ? var->location : attr,
-                               var->name);
+           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 >= VERT_ATTRIB_GENERIC0) {
+        } else if (var->location >= generic_base) {
            used_locations |= (use_mask << attr);
         }
       }
@@ -1321,14 +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
@@ -1339,14 +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);
    }
 
@@ -1377,8 +1482,9 @@ demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
 }
 
 
-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. */
@@ -1434,6 +1540,8 @@ assign_varying_locations(struct gl_shader_program *prog,
       }
    }
 
+   unsigned varying_vectors = 0;
+
    foreach_list(node, consumer->ir) {
       ir_variable *const var = ((ir_instruction *) node)->as_variable();
 
@@ -1455,33 +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(struct gl_context *ctx, struct gl_shader_program *prog)
 {
-   void *mem_ctx = talloc_init("temporary linker context");
+   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.
     */
@@ -1524,8 +1655,8 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
    assert(max_version <= 130);
    if ((max_version >= 130 || min_version == 100)
        && min_version != max_version) {
-      linker_error_printf(prog, "all shaders must use same shading "
-                         "language version\n");
+      linker_error(prog, "all shaders must use same shading "
+                  "language version\n");
       goto done;
    }
 
@@ -1582,7 +1713,7 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
            break;
       }
 
-      /* Validate the inputs of each stage with the output of the preceeding
+      /* Validate the inputs of each stage with the output of the preceding
        * stage.
        */
       for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
@@ -1608,6 +1739,10 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
       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))
         ;
    }
@@ -1616,16 +1751,17 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
 
    assign_uniform_locations(prog);
 
-   if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
-      /* 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)) {
-        prog->LinkStatus = false;
-        goto done;
-      }
+   /* 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;
@@ -1638,9 +1774,12 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
       if (prog->_LinkedShaders[i] == NULL)
         continue;
 
-      assign_varying_locations(prog,
-                              prog->_LinkedShaders[prev],
-                              prog->_LinkedShaders[i]);
+      if (!assign_varying_locations(ctx, prog,
+                                   prog->_LinkedShaders[prev],
+                                   prog->_LinkedShaders[i])) {
+        goto done;
+      }
+
       prev = i;
    }
 
@@ -1663,6 +1802,18 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
       demote_shader_inputs_and_outputs(sh, ir_var_in);
    }
 
+   /* 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:
@@ -1676,5 +1827,5 @@ done:
       reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir);
    }
 
-   talloc_free(mem_ctx);
+   ralloc_free(mem_ctx);
 }