fontconfig libX11 mesa mkfontscale xserver git update 11 jan 2013

fontconfig: 0831c1770e4bac7269a190936bbb0529d747e233
libX11: 0b148750027fd0557c5ed93afda861ddf4b92e0f
mkfontscale: 9cbe3256bc932b82f2435b23cda0931f4f5f5ba2
xserver: 6703a7c7cf1a349c137e247a0c8eb462ff7b07be
mesa: babab2876080af0fe65249dff559244aebd0b87e

13 files changed, 1414 insertions, 1217 deletions

diff --git a/mesalib/src/glsl/.gitignore b/mesalib/src/glsl/.gitignore
index 068d4874b..4eb4fef9b 100644
--- a/mesalib/src/glsl/.gitignore
+++ b/mesalib/src/glsl/.gitignore
@@ -5,4 +5,3 @@ glsl_parser.h
 glsl_parser.output
 builtin_function.cpp
 glsl_test
-/Makefile
diff --git a/mesalib/src/glsl/Makefile.sources b/mesalib/src/glsl/Makefile.sources
index d984c5ca7..2227c5ef5 100644
--- a/mesalib/src/glsl/Makefile.sources
+++ b/mesalib/src/glsl/Makefile.sources
@@ -46,6 +46,7 @@ LIBGLSL_FILES = \
 	$(GLSL_SRCDIR)/link_functions.cpp \
 	$(GLSL_SRCDIR)/link_uniforms.cpp \
 	$(GLSL_SRCDIR)/link_uniform_initializers.cpp \
+	$(GLSL_SRCDIR)/link_varyings.cpp \
 	$(GLSL_SRCDIR)/loop_analysis.cpp \
 	$(GLSL_SRCDIR)/loop_controls.cpp \
 	$(GLSL_SRCDIR)/loop_unroll.cpp \
diff --git a/mesalib/src/glsl/Makefile.template b/mesalib/src/glsl/Makefile.template
deleted file mode 100644
index 974987a0a..000000000
--- a/mesalib/src/glsl/Makefile.template
+++ /dev/null
@@ -1,50 +0,0 @@
-# src/glsl/Makefile.template
-
-# Template makefile for glsl libraries.
-#
-# Usage:
-#   The minimum that the including makefile needs to define
-#   is TOP, LIBNAME and one of of the *_SOURCES.
-#
-# Optional defines:
-#   LIBRARY_INCLUDES are appended to the list of includes directories.
-#   LIBRARY_DEFINES is not used for makedepend, but for compilation.
-
-
-### Basic defines ###
-
-OBJECTS = $(C_SOURCES:.c=.o)
-
-INCLUDES = \
-	-I. \
-	$(LIBRARY_INCLUDES)
-
-
-##### TARGETS #####
-
-default: depend lib$(LIBNAME).a
-
-lib$(LIBNAME).a: $(OBJECTS) Makefile $(TOP)/src/glsl/Makefile.template
-	$(MKLIB) -o $(LIBNAME) -static $(OBJECTS)
-
-depend: $(C_SOURCES)
-	rm -f depend
-	touch depend
-	$(MKDEP) $(MKDEP_OPTIONS) $(INCLUDES) $(C_SOURCES) 2> /dev/null
-
-# Remove .o and backup files
-clean:
-	rm -f $(OBJECTS) lib$(LIBNAME).a depend depend.bak
-
-# Dummy target
-install:
-	@echo -n ""
-
-
-##### RULES #####
-
-.c.o:
-	$(CC) -c $(INCLUDES) $(CFLAGS) $(LIBRARY_DEFINES) $< -o $@
-
--include depend
-
diff --git a/mesalib/src/glsl/ast_to_hir.cpp b/mesalib/src/glsl/ast_to_hir.cpp
index 94b63f682..f934c8e2d 100644
--- a/mesalib/src/glsl/ast_to_hir.cpp
+++ b/mesalib/src/glsl/ast_to_hir.cpp
@@ -1910,12 +1910,36 @@ ast_type_specifier::glsl_type(const char **name,
 }
 
 
+/**
+ * Determine whether a toplevel variable declaration declares a varying.  This
+ * function operates by examining the variable's mode and the shader target,
+ * so it correctly identifies linkage variables regardless of whether they are
+ * declared using the deprecated "varying" syntax or the new "in/out" syntax.
+ *
+ * Passing a non-toplevel variable declaration (e.g. a function parameter) to
+ * this function will produce undefined results.
+ */
+static bool
+is_varying_var(ir_variable *var, _mesa_glsl_parser_targets target)
+{
+   switch (target) {
+   case vertex_shader:
+      return var->mode == ir_var_out;
+   case fragment_shader:
+      return var->mode == ir_var_in;
+   default:
+      return var->mode == ir_var_out || var->mode == ir_var_in;
+   }
+}
+
+
 static void
 apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
 				 ir_variable *var,
 				 struct _mesa_glsl_parse_state *state,
 				 YYLTYPE *loc,
-				 bool ubo_qualifiers_valid)
+				 bool ubo_qualifiers_valid,
+                                 bool is_parameter)
 {
    if (qual->flags.q.invariant) {
       if (var->used) {
@@ -1944,27 +1968,6 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
 		       _mesa_glsl_shader_target_name(state->target));
    }
 
-   /* From page 25 (page 31 of the PDF) of the GLSL 1.10 spec:
-    *
-    *     "The varying qualifier can be used only with the data types
-    *     float, vec2, vec3, vec4, mat2, mat3, and mat4, or arrays of
-    *     these."
-    */
-   if (qual->flags.q.varying) {
-      const glsl_type *non_array_type;
-
-      if (var->type && var->type->is_array())
-	 non_array_type = var->type->fields.array;
-      else
-	 non_array_type = var->type;
-
-      if (non_array_type && non_array_type->base_type != GLSL_TYPE_FLOAT) {
-	 var->type = glsl_type::error_type;
-	 _mesa_glsl_error(loc, state,
-			  "varying variables must be of base type float");
-      }
-   }
-
    /* If there is no qualifier that changes the mode of the variable, leave
     * the setting alone.
     */
@@ -1979,6 +1982,54 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
    else if (qual->flags.q.uniform)
       var->mode = ir_var_uniform;
 
+   if (!is_parameter && is_varying_var(var, state->target)) {
+      /* This variable is being used to link data between shader stages (in
+       * pre-glsl-1.30 parlance, it's a "varying").  Check that it has a type
+       * that is allowed for such purposes.
+       *
+       * From page 25 (page 31 of the PDF) of the GLSL 1.10 spec:
+       *
+       *     "The varying qualifier can be used only with the data types
+       *     float, vec2, vec3, vec4, mat2, mat3, and mat4, or arrays of
+       *     these."
+       *
+       * This was relaxed in GLSL version 1.30 and GLSL ES version 3.00.  From
+       * page 31 (page 37 of the PDF) of the GLSL 1.30 spec:
+       *
+       *     "Fragment inputs can only be signed and unsigned integers and
+       *     integer vectors, float, floating-point vectors, matrices, or
+       *     arrays of these. Structures cannot be input.
+       *
+       * Similar text exists in the section on vertex shader outputs.
+       *
+       * Similar text exists in the GLSL ES 3.00 spec, except that the GLSL ES
+       * 3.00 spec claims to allow structs as well.  However, this is likely
+       * an error, since section 11 of the spec ("Counting of Inputs and
+       * Outputs") enumerates all possible types of interstage linkage
+       * variables, and it does not mention structs.
+       */
+      switch (var->type->get_scalar_type()->base_type) {
+      case GLSL_TYPE_FLOAT:
+         /* Ok in all GLSL versions */
+         break;
+      case GLSL_TYPE_UINT:
+      case GLSL_TYPE_INT:
+         if (state->is_version(130, 300))
+            break;
+         _mesa_glsl_error(loc, state,
+                          "varying variables must be of base type float in %s",
+                          state->get_version_string());
+         break;
+      case GLSL_TYPE_STRUCT:
+         _mesa_glsl_error(loc, state,
+                          "varying variables may not be of type struct");
+         break;
+      default:
+         _mesa_glsl_error(loc, state, "illegal type for a varying variable");
+         break;
+      }
+   }
+
    if (state->all_invariant && (state->current_function == NULL)) {
       switch (state->target) {
       case vertex_shader:
@@ -2626,7 +2677,7 @@ ast_declarator_list::hir(exec_list *instructions,
       }
 
       apply_type_qualifier_to_variable(& this->type->qualifier, var, state,
-				       & loc, this->ubo_qualifiers_valid);
+				       & loc, this->ubo_qualifiers_valid, false);
 
       if (this->type->qualifier.flags.q.invariant) {
 	 if ((state->target == vertex_shader) && !(var->mode == ir_var_out ||
@@ -3065,7 +3116,7 @@ ast_parameter_declarator::hir(exec_list *instructions,
     * for function parameters the default mode is 'in'.
     */
    apply_type_qualifier_to_variable(& this->type->qualifier, var, state, & loc,
-				    false);
+				    false, true);
 
    /* From page 17 (page 23 of the PDF) of the GLSL 1.20 spec:
     *
diff --git a/mesalib/src/glsl/builtin_compiler/.gitignore b/mesalib/src/glsl/builtin_compiler/.gitignore
index 40c551baa..ea7d5de9c 100644
--- a/mesalib/src/glsl/builtin_compiler/.gitignore
+++ b/mesalib/src/glsl/builtin_compiler/.gitignore
@@ -3,4 +3,3 @@ glcpp-lex.c
 glcpp-parse.c
 glcpp-parse.h
 glcpp-parse.output
-/Makefile
diff --git a/mesalib/src/glsl/glcpp/.gitignore b/mesalib/src/glsl/glcpp/.gitignore
index 64033e2aa..01d2888e7 100644
--- a/mesalib/src/glsl/glcpp/.gitignore
+++ b/mesalib/src/glsl/glcpp/.gitignore
@@ -3,5 +3,3 @@ glcpp-lex.c
 glcpp-parse.output
 glcpp-parse.c
 glcpp-parse.h
-tests/*.out
-/Makefile
diff --git a/mesalib/src/glsl/glsl_parser.yy b/mesalib/src/glsl/glsl_parser.yy
index d8494667b..88aae64d4 100644
--- a/mesalib/src/glsl/glsl_parser.yy
+++ b/mesalib/src/glsl/glsl_parser.yy
@@ -1542,7 +1542,6 @@ struct_declarator:
 	   void *ctx = state;
 	   $$ = new(ctx) ast_declaration($1, false, NULL, NULL);
 	   $$->set_location(yylloc);
-	   state->symbols->add_variable(new(state) ir_variable(NULL, $1, ir_var_auto));
 	}
 	| any_identifier '[' constant_expression ']'
 	{
diff --git a/mesalib/src/glsl/link_varyings.cpp b/mesalib/src/glsl/link_varyings.cpp
new file mode 100644
index 000000000..5c27f231e
--- /dev/null
+++ b/mesalib/src/glsl/link_varyings.cpp
@@ -0,0 +1,1051 @@
+/*
+ * Copyright © 2012 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file link_varyings.cpp
+ *
+ * Linker functions related specifically to linking varyings between shader
+ * stages.
+ */
+
+
+#include "main/mtypes.h"
+#include "glsl_symbol_table.h"
+#include "ir_optimization.h"
+#include "linker.h"
+#include "link_varyings.h"
+#include "main/macros.h"
+
+
+/**
+ * Validate that outputs from one stage match inputs of another
+ */
+bool
+cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
+				 gl_shader *producer, gl_shader *consumer)
+{
+   glsl_symbol_table parameters;
+   /* FINISHME: Figure these out dynamically. */
+   const char *const producer_stage = "vertex";
+   const char *const consumer_stage = "fragment";
+
+   /* Find all shader outputs in the "producer" stage.
+    */
+   foreach_list(node, producer->ir) {
+      ir_variable *const var = ((ir_instruction *) node)->as_variable();
+
+      /* FINISHME: For geometry shaders, this should also look for inout
+       * FINISHME: variables.
+       */
+      if ((var == NULL) || (var->mode != ir_var_out))
+	 continue;
+
+      parameters.add_variable(var);
+   }
+
+
+   /* Find all shader inputs in the "consumer" stage.  Any variables that have
+    * matching outputs already in the symbol table must have the same type and
+    * qualifiers.
+    */
+   foreach_list(node, consumer->ir) {
+      ir_variable *const input = ((ir_instruction *) node)->as_variable();
+
+      /* FINISHME: For geometry shaders, this should also look for inout
+       * FINISHME: variables.
+       */
+      if ((input == NULL) || (input->mode != ir_var_in))
+	 continue;
+
+      ir_variable *const output = parameters.get_variable(input->name);
+      if (output != NULL) {
+	 /* Check that the types match between stages.
+	  */
+	 if (input->type != output->type) {
+	    /* 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(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(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(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;
+	 }
+      }
+   }
+
+   return true;
+}
+
+
+/**
+ * Initialize this object based on a string that was passed to
+ * glTransformFeedbackVaryings.  If there is a parse error, the error is
+ * reported using linker_error(), and false is returned.
+ */
+bool
+tfeedback_decl::init(struct gl_context *ctx, struct gl_shader_program *prog,
+                     const void *mem_ctx, const char *input)
+{
+   /* We don't have to be pedantic about what is a valid GLSL variable name,
+    * because any variable with an invalid name can't exist in the IR anyway.
+    */
+
+   this->location = -1;
+   this->orig_name = input;
+   this->is_clip_distance_mesa = false;
+   this->skip_components = 0;
+   this->next_buffer_separator = false;
+
+   if (ctx->Extensions.ARB_transform_feedback3) {
+      /* Parse gl_NextBuffer. */
+      if (strcmp(input, "gl_NextBuffer") == 0) {
+         this->next_buffer_separator = true;
+         return true;
+      }
+
+      /* Parse gl_SkipComponents. */
+      if (strcmp(input, "gl_SkipComponents1") == 0)
+         this->skip_components = 1;
+      else if (strcmp(input, "gl_SkipComponents2") == 0)
+         this->skip_components = 2;
+      else if (strcmp(input, "gl_SkipComponents3") == 0)
+         this->skip_components = 3;
+      else if (strcmp(input, "gl_SkipComponents4") == 0)
+         this->skip_components = 4;
+
+      if (this->skip_components)
+         return true;
+   }
+
+   /* Parse a declaration. */
+   const char *bracket = strrchr(input, '[');
+
+   if (bracket) {
+      this->var_name = ralloc_strndup(mem_ctx, input, bracket - input);
+      if (sscanf(bracket, "[%u]", &this->array_subscript) != 1) {
+         linker_error(prog, "Cannot parse transform feedback varying %s", input);
+         return false;
+      }
+      this->is_subscripted = true;
+   } else {
+      this->var_name = ralloc_strdup(mem_ctx, input);
+      this->is_subscripted = false;
+   }
+
+   /* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this
+    * class must behave specially to account for the fact that gl_ClipDistance
+    * is converted from a float[8] to a vec4[2].
+    */
+   if (ctx->ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
+       strcmp(this->var_name, "gl_ClipDistance") == 0) {
+      this->is_clip_distance_mesa = true;
+   }
+
+   return true;
+}
+
+
+/**
+ * Determine whether two tfeedback_decl objects refer to the same variable and
+ * array index (if applicable).
+ */
+bool
+tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y)
+{
+   assert(x.is_varying() && y.is_varying());
+
+   if (strcmp(x.var_name, y.var_name) != 0)
+      return false;
+   if (x.is_subscripted != y.is_subscripted)
+      return false;
+   if (x.is_subscripted && x.array_subscript != y.array_subscript)
+      return false;
+   return true;
+}
+
+
+/**
+ * Assign a location for this tfeedback_decl object based on the location
+ * assignment in output_var.
+ *
+ * If an error occurs, the error is reported through linker_error() and false
+ * is returned.
+ */
+bool
+tfeedback_decl::assign_location(struct gl_context *ctx,
+                                struct gl_shader_program *prog,
+                                ir_variable *output_var)
+{
+   assert(this->is_varying());
+
+   if (output_var->type->is_array()) {
+      /* Array variable */
+      const unsigned matrix_cols =
+         output_var->type->fields.array->matrix_columns;
+      const unsigned vector_elements =
+         output_var->type->fields.array->vector_elements;
+      unsigned actual_array_size = this->is_clip_distance_mesa ?
+         prog->Vert.ClipDistanceArraySize : output_var->type->array_size();
+
+      if (this->is_subscripted) {
+         /* Check array bounds. */
+         if (this->array_subscript >= actual_array_size) {
+            linker_error(prog, "Transform feedback varying %s has index "
+                         "%i, but the array size is %u.",
+                         this->orig_name, this->array_subscript,
+                         actual_array_size);
+            return false;
+         }
+         if (this->is_clip_distance_mesa) {
+            this->location =
+               output_var->location + this->array_subscript / 4;
+            this->location_frac = this->array_subscript % 4;
+         } else {
+            unsigned fine_location
+               = output_var->location * 4 + output_var->location_frac;
+            unsigned array_elem_size = vector_elements * matrix_cols;
+            fine_location += array_elem_size * this->array_subscript;
+            this->location = fine_location / 4;
+            this->location_frac = fine_location % 4;
+         }
+         this->size = 1;
+      } else {
+         this->location = output_var->location;
+         this->location_frac = output_var->location_frac;
+         this->size = actual_array_size;
+      }
+      this->vector_elements = vector_elements;
+      this->matrix_columns = matrix_cols;
+      if (this->is_clip_distance_mesa)
+         this->type = GL_FLOAT;
+      else
+         this->type = output_var->type->fields.array->gl_type;
+   } else {
+      /* Regular variable (scalar, vector, or matrix) */
+      if (this->is_subscripted) {
+         linker_error(prog, "Transform feedback varying %s requested, "
+                      "but %s is not an array.",
+                      this->orig_name, this->var_name);
+         return false;
+      }
+      this->location = output_var->location;
+      this->location_frac = output_var->location_frac;
+      this->size = 1;
+      this->vector_elements = output_var->type->vector_elements;
+      this->matrix_columns = output_var->type->matrix_columns;
+      this->type = output_var->type->gl_type;
+   }
+
+   /* From GL_EXT_transform_feedback:
+    *   A program will fail to link if:
+    *
+    *   * the total number of components to capture in any varying
+    *     variable in <varyings> is greater than the constant
+    *     MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the
+    *     buffer mode is SEPARATE_ATTRIBS_EXT;
+    */
+   if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
+       this->num_components() >
+       ctx->Const.MaxTransformFeedbackSeparateComponents) {
+      linker_error(prog, "Transform feedback varying %s exceeds "
+                   "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.",
+                   this->orig_name);
+      return false;
+   }
+
+   return true;
+}
+
+
+unsigned
+tfeedback_decl::get_num_outputs() const
+{
+   if (!this->is_varying()) {
+      return 0;
+   }
+
+   return (this->num_components() + this->location_frac + 3)/4;
+}
+
+
+/**
+ * Update gl_transform_feedback_info to reflect this tfeedback_decl.
+ *
+ * If an error occurs, the error is reported through linker_error() and false
+ * is returned.
+ */
+bool
+tfeedback_decl::store(struct gl_context *ctx, struct gl_shader_program *prog,
+                      struct gl_transform_feedback_info *info,
+                      unsigned buffer, const unsigned max_outputs) const
+{
+   assert(!this->next_buffer_separator);
+
+   /* Handle gl_SkipComponents. */
+   if (this->skip_components) {
+      info->BufferStride[buffer] += this->skip_components;
+      return true;
+   }
+
+   /* From GL_EXT_transform_feedback:
+    *   A program will fail to link if:
+    *
+    *     * the total number of components to capture is greater than
+    *       the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT
+    *       and the buffer mode is INTERLEAVED_ATTRIBS_EXT.
+    */
+   if (prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS &&
+       info->BufferStride[buffer] + this->num_components() >
+       ctx->Const.MaxTransformFeedbackInterleavedComponents) {
+      linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
+                   "limit has been exceeded.");
+      return false;
+   }
+
+   unsigned location = this->location;
+   unsigned location_frac = this->location_frac;
+   unsigned num_components = this->num_components();
+   while (num_components > 0) {
+      unsigned output_size = MIN2(num_components, 4 - location_frac);
+      assert(info->NumOutputs < max_outputs);
+      info->Outputs[info->NumOutputs].ComponentOffset = location_frac;
+      info->Outputs[info->NumOutputs].OutputRegister = location;
+      info->Outputs[info->NumOutputs].NumComponents = output_size;
+      info->Outputs[info->NumOutputs].OutputBuffer = buffer;
+      info->Outputs[info->NumOutputs].DstOffset = info->BufferStride[buffer];
+      ++info->NumOutputs;
+      info->BufferStride[buffer] += output_size;
+      num_components -= output_size;
+      location++;
+      location_frac = 0;
+   }
+
+   info->Varyings[info->NumVarying].Name = ralloc_strdup(prog, this->orig_name);
+   info->Varyings[info->NumVarying].Type = this->type;
+   info->Varyings[info->NumVarying].Size = this->size;
+   info->NumVarying++;
+
+   return true;
+}
+
+
+ir_variable *
+tfeedback_decl::find_output_var(gl_shader_program *prog,
+                                gl_shader *producer) const
+{
+   const char *name = this->is_clip_distance_mesa
+      ? "gl_ClipDistanceMESA" : this->var_name;
+   ir_variable *var = producer->symbols->get_variable(name);
+   if (var && var->mode == ir_var_out)
+      return var;
+
+   /* From GL_EXT_transform_feedback:
+    *   A program will fail to link if:
+    *
+    *   * any variable name specified in the <varyings> array is not
+    *     declared as an output in the geometry shader (if present) or
+    *     the vertex shader (if no geometry shader is present);
+    */
+   linker_error(prog, "Transform feedback varying %s undeclared.",
+                this->orig_name);
+   return NULL;
+}
+
+
+/**
+ * Parse all the transform feedback declarations that were passed to
+ * glTransformFeedbackVaryings() and store them in tfeedback_decl objects.
+ *
+ * If an error occurs, the error is reported through linker_error() and false
+ * is returned.
+ */
+bool
+parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,
+                      const void *mem_ctx, unsigned num_names,
+                      char **varying_names, tfeedback_decl *decls)
+{
+   for (unsigned i = 0; i < num_names; ++i) {
+      if (!decls[i].init(ctx, prog, mem_ctx, varying_names[i]))
+         return false;
+
+      if (!decls[i].is_varying())
+         continue;
+
+      /* From GL_EXT_transform_feedback:
+       *   A program will fail to link if:
+       *
+       *   * any two entries in the <varyings> array specify the same varying
+       *     variable;
+       *
+       * We interpret this to mean "any two entries in the <varyings> array
+       * specify the same varying variable and array index", since transform
+       * feedback of arrays would be useless otherwise.
+       */
+      for (unsigned j = 0; j < i; ++j) {
+         if (!decls[j].is_varying())
+            continue;
+
+         if (tfeedback_decl::is_same(decls[i], decls[j])) {
+            linker_error(prog, "Transform feedback varying %s specified "
+                         "more than once.", varying_names[i]);
+            return false;
+         }
+      }
+   }
+   return true;
+}
+
+
+/**
+ * Store transform feedback location assignments into
+ * prog->LinkedTransformFeedback based on the data stored in tfeedback_decls.
+ *
+ * If an error occurs, the error is reported through linker_error() and false
+ * is returned.
+ */
+bool
+store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
+                     unsigned num_tfeedback_decls,
+                     tfeedback_decl *tfeedback_decls)
+{
+   bool separate_attribs_mode =
+      prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
+
+   ralloc_free(prog->LinkedTransformFeedback.Varyings);
+   ralloc_free(prog->LinkedTransformFeedback.Outputs);
+
+   memset(&prog->LinkedTransformFeedback, 0,
+          sizeof(prog->LinkedTransformFeedback));
+
+   prog->LinkedTransformFeedback.Varyings =
+      rzalloc_array(prog,
+		    struct gl_transform_feedback_varying_info,
+		    num_tfeedback_decls);
+
+   unsigned num_outputs = 0;
+   for (unsigned i = 0; i < num_tfeedback_decls; ++i)
+      num_outputs += tfeedback_decls[i].get_num_outputs();
+
+   prog->LinkedTransformFeedback.Outputs =
+      rzalloc_array(prog,
+                    struct gl_transform_feedback_output,
+                    num_outputs);
+
+   unsigned num_buffers = 0;
+
+   if (separate_attribs_mode) {
+      /* GL_SEPARATE_ATTRIBS */
+      for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
+         if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback,
+                                       num_buffers, num_outputs))
+            return false;
+
+         num_buffers++;
+      }
+   }
+   else {
+      /* GL_INVERLEAVED_ATTRIBS */
+      for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
+         if (tfeedback_decls[i].is_next_buffer_separator()) {
+            num_buffers++;
+            continue;
+         }
+
+         if (!tfeedback_decls[i].store(ctx, prog,
+                                       &prog->LinkedTransformFeedback,
+                                       num_buffers, num_outputs))
+            return false;
+      }
+      num_buffers++;
+   }
+
+   assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs);
+
+   prog->LinkedTransformFeedback.NumBuffers = num_buffers;
+   return true;
+}
+
+
+/**
+ * Data structure recording the relationship between outputs of one shader
+ * stage (the "producer") and inputs of another (the "consumer").
+ */
+class varying_matches
+{
+public:
+   varying_matches(bool disable_varying_packing);
+   ~varying_matches();
+   void record(ir_variable *producer_var, ir_variable *consumer_var);
+   unsigned assign_locations();
+   void store_locations(unsigned producer_base, unsigned consumer_base) const;
+
+private:
+   /**
+    * If true, this driver disables varying packing, so all varyings need to
+    * be aligned on slot boundaries, and take up a number of slots equal to
+    * their number of matrix columns times their array size.
+    */
+   const bool disable_varying_packing;
+
+   /**
+    * Enum representing the order in which varyings are packed within a
+    * packing class.
+    *
+    * Currently we pack vec4's first, then vec2's, then scalar values, then
+    * vec3's.  This order ensures that the only vectors that are at risk of
+    * having to be "double parked" (split between two adjacent varying slots)
+    * are the vec3's.
+    */
+   enum packing_order_enum {
+      PACKING_ORDER_VEC4,
+      PACKING_ORDER_VEC2,
+      PACKING_ORDER_SCALAR,
+      PACKING_ORDER_VEC3,
+   };
+
+   static unsigned compute_packing_class(ir_variable *var);
+   static packing_order_enum compute_packing_order(ir_variable *var);
+   static int match_comparator(const void *x_generic, const void *y_generic);
+
+   /**
+    * Structure recording the relationship between a single producer output
+    * and a single consumer input.
+    */
+   struct match {
+      /**
+       * Packing class for this varying, computed by compute_packing_class().
+       */
+      unsigned packing_class;
+
+      /**
+       * Packing order for this varying, computed by compute_packing_order().
+       */
+      packing_order_enum packing_order;
+      unsigned num_components;
+
+      /**
+       * The output variable in the producer stage.
+       */
+      ir_variable *producer_var;
+
+      /**
+       * The input variable in the consumer stage.
+       */
+      ir_variable *consumer_var;
+
+      /**
+       * The location which has been assigned for this varying.  This is
+       * expressed in multiples of a float, with the first generic varying
+       * (i.e. the one referred to by VERT_RESULT_VAR0 or FRAG_ATTRIB_VAR0)
+       * represented by the value 0.
+       */
+      unsigned generic_location;
+   } *matches;
+
+   /**
+    * The number of elements in the \c matches array that are currently in
+    * use.
+    */
+   unsigned num_matches;
+
+   /**
+    * The number of elements that were set aside for the \c matches array when
+    * it was allocated.
+    */
+   unsigned matches_capacity;
+};
+
+
+varying_matches::varying_matches(bool disable_varying_packing)
+   : disable_varying_packing(disable_varying_packing)
+{
+   /* Note: this initial capacity is rather arbitrarily chosen to be large
+    * enough for many cases without wasting an unreasonable amount of space.
+    * varying_matches::record() will resize the array if there are more than
+    * this number of varyings.
+    */
+   this->matches_capacity = 8;
+   this->matches = (match *)
+      malloc(sizeof(*this->matches) * this->matches_capacity);
+   this->num_matches = 0;
+}
+
+
+varying_matches::~varying_matches()
+{
+   free(this->matches);
+}
+
+
+/**
+ * Record the given producer/consumer variable pair in the list of variables
+ * that should later be assigned locations.
+ *
+ * It is permissible for \c consumer_var to be NULL (this happens if a
+ * variable is output by the producer and consumed by transform feedback, but
+ * not consumed by the consumer).
+ *
+ * If \c producer_var has already been paired up with a consumer_var, or
+ * producer_var is part of fixed pipeline functionality (and hence already has
+ * a location assigned), this function has no effect.
+ */
+void
+varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var)
+{
+   if (!producer_var->is_unmatched_generic_inout) {
+      /* Either a location already exists for this variable (since it is part
+       * of fixed functionality), or it has already been recorded as part of a
+       * previous match.
+       */
+      return;
+   }
+
+   if (this->num_matches == this->matches_capacity) {
+      this->matches_capacity *= 2;
+      this->matches = (match *)
+         realloc(this->matches,
+                 sizeof(*this->matches) * this->matches_capacity);
+   }
+   this->matches[this->num_matches].packing_class
+      = this->compute_packing_class(producer_var);
+   this->matches[this->num_matches].packing_order
+      = this->compute_packing_order(producer_var);
+   if (this->disable_varying_packing) {
+      unsigned slots = producer_var->type->is_array()
+         ? (producer_var->type->length
+            * producer_var->type->fields.array->matrix_columns)
+         : producer_var->type->matrix_columns;
+      this->matches[this->num_matches].num_components = 4 * slots;
+   } else {
+      this->matches[this->num_matches].num_components
+         = producer_var->type->component_slots();
+   }
+   this->matches[this->num_matches].producer_var = producer_var;
+   this->matches[this->num_matches].consumer_var = consumer_var;
+   this->num_matches++;
+   producer_var->is_unmatched_generic_inout = 0;
+   if (consumer_var)
+      consumer_var->is_unmatched_generic_inout = 0;
+}
+
+
+/**
+ * Choose locations for all of the variable matches that were previously
+ * passed to varying_matches::record().
+ */
+unsigned
+varying_matches::assign_locations()
+{
+   /* Sort varying matches into an order that makes them easy to pack. */
+   qsort(this->matches, this->num_matches, sizeof(*this->matches),
+         &varying_matches::match_comparator);
+
+   unsigned generic_location = 0;
+
+   for (unsigned i = 0; i < this->num_matches; i++) {
+      /* Advance to the next slot if this varying has a different packing
+       * class than the previous one, and we're not already on a slot
+       * boundary.
+       */
+      if (i > 0 &&
+          this->matches[i - 1].packing_class
+          != this->matches[i].packing_class) {
+         generic_location = ALIGN(generic_location, 4);
+      }
+
+      this->matches[i].generic_location = generic_location;
+
+      generic_location += this->matches[i].num_components;
+   }
+
+   return (generic_location + 3) / 4;
+}
+
+
+/**
+ * Update the producer and consumer shaders to reflect the locations
+ * assignments that were made by varying_matches::assign_locations().
+ */
+void
+varying_matches::store_locations(unsigned producer_base,
+                                 unsigned consumer_base) const
+{
+   for (unsigned i = 0; i < this->num_matches; i++) {
+      ir_variable *producer_var = this->matches[i].producer_var;
+      ir_variable *consumer_var = this->matches[i].consumer_var;
+      unsigned generic_location = this->matches[i].generic_location;
+      unsigned slot = generic_location / 4;
+      unsigned offset = generic_location % 4;
+
+      producer_var->location = producer_base + slot;
+      producer_var->location_frac = offset;
+      if (consumer_var) {
+         assert(consumer_var->location == -1);
+         consumer_var->location = consumer_base + slot;
+         consumer_var->location_frac = offset;
+      }
+   }
+}
+
+
+/**
+ * Compute the "packing class" of the given varying.  This is an unsigned
+ * integer with the property that two variables in the same packing class can
+ * be safely backed into the same vec4.
+ */
+unsigned
+varying_matches::compute_packing_class(ir_variable *var)
+{
+   /* Without help from the back-end, there is no way to pack together
+    * variables with different interpolation types, because
+    * lower_packed_varyings must choose exactly one interpolation type for
+    * each packed varying it creates.
+    *
+    * However, we can safely pack together floats, ints, and uints, because:
+    *
+    * - varyings of base type "int" and "uint" must use the "flat"
+    *   interpolation type, which can only occur in GLSL 1.30 and above.
+    *
+    * - On platforms that support GLSL 1.30 and above, lower_packed_varyings
+    *   can store flat floats as ints without losing any information (using
+    *   the ir_unop_bitcast_* opcodes).
+    *
+    * Therefore, the packing class depends only on the interpolation type.
+    */
+   unsigned packing_class = var->centroid ? 1 : 0;
+   packing_class *= 4;
+   packing_class += var->interpolation;
+   return packing_class;
+}
+
+
+/**
+ * Compute the "packing order" of the given varying.  This is a sort key we
+ * use to determine when to attempt to pack the given varying relative to
+ * other varyings in the same packing class.
+ */
+varying_matches::packing_order_enum
+varying_matches::compute_packing_order(ir_variable *var)
+{
+   const glsl_type *element_type = var->type;
+
+   /* FINISHME: Support for "varying" records in GLSL 1.50. */
+   while (element_type->base_type == GLSL_TYPE_ARRAY) {
+      element_type = element_type->fields.array;
+   }
+
+   switch (element_type->vector_elements) {
+   case 1: return PACKING_ORDER_SCALAR;
+   case 2: return PACKING_ORDER_VEC2;
+   case 3: return PACKING_ORDER_VEC3;
+   case 4: return PACKING_ORDER_VEC4;
+   default:
+      assert(!"Unexpected value of vector_elements");
+      return PACKING_ORDER_VEC4;
+   }
+}
+
+
+/**
+ * Comparison function passed to qsort() to sort varyings by packing_class and
+ * then by packing_order.
+ */
+int
+varying_matches::match_comparator(const void *x_generic, const void *y_generic)
+{
+   const match *x = (const match *) x_generic;
+   const match *y = (const match *) y_generic;
+
+   if (x->packing_class != y->packing_class)
+      return x->packing_class - y->packing_class;
+   return x->packing_order - y->packing_order;
+}
+
+
+/**
+ * Is the given variable a varying variable to be counted against the
+ * limit in ctx->Const.MaxVarying?
+ * This includes variables such as texcoords, colors and generic
+ * varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord.
+ */
+static bool
+is_varying_var(GLenum shaderType, const ir_variable *var)
+{
+   /* Only fragment shaders will take a varying variable as an input */
+   if (shaderType == GL_FRAGMENT_SHADER &&
+       var->mode == ir_var_in) {
+      switch (var->location) {
+      case FRAG_ATTRIB_WPOS:
+      case FRAG_ATTRIB_FACE:
+      case FRAG_ATTRIB_PNTC:
+         return false;
+      default:
+         return true;
+      }
+   }
+   return false;
+}
+
+
+/**
+ * Assign locations for all variables that are produced in one pipeline stage
+ * (the "producer") and consumed in the next stage (the "consumer").
+ *
+ * Variables produced by the producer may also be consumed by transform
+ * feedback.
+ *
+ * \param num_tfeedback_decls is the number of declarations indicating
+ *        variables that may be consumed by transform feedback.
+ *
+ * \param tfeedback_decls is a pointer to an array of tfeedback_decl objects
+ *        representing the result of parsing the strings passed to
+ *        glTransformFeedbackVaryings().  assign_location() will be called for
+ *        each of these objects that matches one of the outputs of the
+ *        producer.
+ *
+ * When num_tfeedback_decls is nonzero, it is permissible for the consumer to
+ * be NULL.  In this case, varying locations are assigned solely based on the
+ * requirements of transform feedback.
+ */
+bool
+assign_varying_locations(struct gl_context *ctx,
+			 void *mem_ctx,
+			 struct gl_shader_program *prog,
+			 gl_shader *producer, gl_shader *consumer,
+                         unsigned num_tfeedback_decls,
+                         tfeedback_decl *tfeedback_decls)
+{
+   /* FINISHME: Set dynamically when geometry shader support is added. */
+   const unsigned producer_base = VERT_RESULT_VAR0;
+   const unsigned consumer_base = FRAG_ATTRIB_VAR0;
+   varying_matches matches(ctx->Const.DisableVaryingPacking);
+
+   /* Operate in a total of three passes.
+    *
+    * 1. Assign locations for any matching inputs and outputs.
+    *
+    * 2. Mark output variables in the producer that do not have locations as
+    *    not being outputs.  This lets the optimizer eliminate them.
+    *
+    * 3. Mark input variables in the consumer that do not have locations as
+    *    not being inputs.  This lets the optimizer eliminate them.
+    */
+
+   foreach_list(node, producer->ir) {
+      ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
+
+      if ((output_var == NULL) || (output_var->mode != ir_var_out))
+	 continue;
+
+      ir_variable *input_var =
+	 consumer ? consumer->symbols->get_variable(output_var->name) : NULL;
+
+      if (input_var && input_var->mode != ir_var_in)
+         input_var = NULL;
+
+      if (input_var) {
+         matches.record(output_var, input_var);
+      }
+   }
+
+   for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
+      if (!tfeedback_decls[i].is_varying())
+         continue;
+
+      ir_variable *output_var
+         = tfeedback_decls[i].find_output_var(prog, producer);
+
+      if (output_var == NULL)
+         return false;
+
+      if (output_var->is_unmatched_generic_inout) {
+         matches.record(output_var, NULL);
+      }
+   }
+
+   const unsigned slots_used = matches.assign_locations();
+   matches.store_locations(producer_base, consumer_base);
+
+   for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
+      if (!tfeedback_decls[i].is_varying())
+         continue;
+
+      ir_variable *output_var
+         = tfeedback_decls[i].find_output_var(prog, producer);
+
+      if (!tfeedback_decls[i].assign_location(ctx, prog, output_var))
+         return false;
+   }
+
+   if (ctx->Const.DisableVaryingPacking) {
+      /* Transform feedback code assumes varyings are packed, so if the driver
+       * has disabled varying packing, make sure it does not support transform
+       * feedback.
+       */
+      assert(!ctx->Extensions.EXT_transform_feedback);
+   } else {
+      lower_packed_varyings(mem_ctx, producer_base, slots_used, ir_var_out,
+                            producer);
+      if (consumer) {
+         lower_packed_varyings(mem_ctx, consumer_base, slots_used, ir_var_in,
+                               consumer);
+      }
+   }
+
+   unsigned varying_vectors = 0;
+
+   if (consumer) {
+      foreach_list(node, consumer->ir) {
+         ir_variable *const var = ((ir_instruction *) node)->as_variable();
+
+         if ((var == NULL) || (var->mode != ir_var_in))
+            continue;
+
+         if (var->is_unmatched_generic_inout) {
+            if (prog->Version <= 120) {
+               /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
+                *
+                *     Only those varying variables used (i.e. read) in
+                *     the fragment shader executable must be written to
+                *     by the vertex shader executable; declaring
+                *     superfluous varying variables in a vertex shader is
+                *     permissible.
+                *
+                * We interpret this text as meaning that the VS must
+                * write the variable for the FS to read it.  See
+                * "glsl1-varying read but not written" in piglit.
+                */
+
+               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 if (is_varying_var(consumer->Type, var)) {
+            /* 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->IsES) {
+      if (varying_vectors > ctx->Const.MaxVarying) {
+         if (ctx->Const.GLSLSkipStrictMaxVaryingLimitCheck) {
+            linker_warning(prog, "shader uses too many varying vectors "
+                           "(%u > %u), but the driver will try to optimize "
+                           "them out; this is non-portable out-of-spec "
+                           "behavior\n",
+                           varying_vectors, ctx->Const.MaxVarying);
+         } else {
+            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) {
+         if (ctx->Const.GLSLSkipStrictMaxVaryingLimitCheck) {
+            linker_warning(prog, "shader uses too many varying components "
+                           "(%u > %u), but the driver will try to optimize "
+                           "them out; this is non-portable out-of-spec "
+                           "behavior\n",
+                           float_components, ctx->Const.MaxVarying * 4);
+         } else {
+            linker_error(prog, "shader uses too many varying components "
+                         "(%u > %u)\n",
+                         float_components, ctx->Const.MaxVarying * 4);
+            return false;
+         }
+      }
+   }
+
+   return true;
+}
diff --git a/mesalib/src/glsl/link_varyings.h b/mesalib/src/glsl/link_varyings.h
new file mode 100644
index 000000000..057e4b219
--- /dev/null
+++ b/mesalib/src/glsl/link_varyings.h
@@ -0,0 +1,186 @@
+/*
+ * Copyright © 2012 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+#ifndef GLSL_LINK_VARYINGS_H
+#define GLSL_LINK_VARYINGS_H
+
+/**
+ * \file link_varyings.h
+ *
+ * Linker functions related specifically to linking varyings between shader
+ * stages.
+ */
+
+
+#include "main/glheader.h"
+
+
+struct gl_shader_program;
+struct gl_shader;
+class ir_variable;
+
+
+/**
+ * Data structure tracking information about a transform feedback declaration
+ * during linking.
+ */
+class tfeedback_decl
+{
+public:
+   bool init(struct gl_context *ctx, struct gl_shader_program *prog,
+             const void *mem_ctx, const char *input);
+   static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);
+   bool assign_location(struct gl_context *ctx, struct gl_shader_program *prog,
+                        ir_variable *output_var);
+   unsigned get_num_outputs() const;
+   bool store(struct gl_context *ctx, struct gl_shader_program *prog,
+              struct gl_transform_feedback_info *info, unsigned buffer,
+              const unsigned max_outputs) const;
+   ir_variable *find_output_var(gl_shader_program *prog,
+                                gl_shader *producer) const;
+
+   bool is_next_buffer_separator() const
+   {
+      return this->next_buffer_separator;
+   }
+
+   bool is_varying() const
+   {
+      return !this->next_buffer_separator && !this->skip_components;
+   }
+
+   /**
+    * The total number of varying components taken up by this variable.  Only
+    * valid if assign_location() has been called.
+    */
+   unsigned num_components() const
+   {
+      if (this->is_clip_distance_mesa)
+         return this->size;
+      else
+         return this->vector_elements * this->matrix_columns * this->size;
+   }
+
+private:
+   /**
+    * The name that was supplied to glTransformFeedbackVaryings.  Used for
+    * error reporting and glGetTransformFeedbackVarying().
+    */
+   const char *orig_name;
+
+   /**
+    * The name of the variable, parsed from orig_name.
+    */
+   const char *var_name;
+
+   /**
+    * True if the declaration in orig_name represents an array.
+    */
+   bool is_subscripted;
+
+   /**
+    * If is_subscripted is true, the subscript that was specified in orig_name.
+    */
+   unsigned array_subscript;
+
+   /**
+    * True if the variable is gl_ClipDistance and the driver lowers
+    * gl_ClipDistance to gl_ClipDistanceMESA.
+    */
+   bool is_clip_distance_mesa;
+
+   /**
+    * The vertex shader output location that the linker assigned for this
+    * variable.  -1 if a location hasn't been assigned yet.
+    */
+   int location;
+
+   /**
+    * If non-zero, then this variable may be packed along with other variables
+    * into a single varying slot, so this offset should be applied when
+    * accessing components.  For example, an offset of 1 means that the x
+    * component of this variable is actually stored in component y of the
+    * location specified by \c location.
+    *
+    * Only valid if location != -1.
+    */
+   unsigned location_frac;
+
+   /**
+    * If location != -1, the number of vector elements in this variable, or 1
+    * if this variable is a scalar.
+    */
+   unsigned vector_elements;
+
+   /**
+    * If location != -1, the number of matrix columns in this variable, or 1
+    * if this variable is not a matrix.
+    */
+   unsigned matrix_columns;
+
+   /** Type of the varying returned by glGetTransformFeedbackVarying() */
+   GLenum type;
+
+   /**
+    * If location != -1, the size that should be returned by
+    * glGetTransformFeedbackVarying().
+    */
+   unsigned size;
+
+   /**
+    * How many components to skip. If non-zero, this is
+    * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3.
+    */
+   unsigned skip_components;
+
+   /**
+    * Whether this is gl_NextBuffer from ARB_transform_feedback3.
+    */
+   bool next_buffer_separator;
+};
+
+
+bool
+cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
+				 gl_shader *producer, gl_shader *consumer);
+
+bool
+parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,
+                      const void *mem_ctx, unsigned num_names,
+                      char **varying_names, tfeedback_decl *decls);
+
+bool
+store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
+                     unsigned num_tfeedback_decls,
+                     tfeedback_decl *tfeedback_decls);
+
+bool
+assign_varying_locations(struct gl_context *ctx,
+			 void *mem_ctx,
+			 struct gl_shader_program *prog,
+			 gl_shader *producer, gl_shader *consumer,
+                         unsigned num_tfeedback_decls,
+                         tfeedback_decl *tfeedback_decls);
+
+#endif /* GLSL_LINK_VARYINGS_H */
diff --git a/mesalib/src/glsl/linker.cpp b/mesalib/src/glsl/linker.cpp
index be08156e0..70f3d5bed 100644
--- a/mesalib/src/glsl/linker.cpp
+++ b/mesalib/src/glsl/linker.cpp
@@ -70,14 +70,13 @@
 #include "program.h"
 #include "program/hash_table.h"
 #include "linker.h"
+#include "link_varyings.h"
 #include "ir_optimization.h"
 
 extern "C" {
 #include "main/shaderobj.h"
 }
 
-#define ALIGN(value, alignment)  (((value) + alignment - 1) & ~(alignment - 1))
-
 /**
  * Visitor that determines whether or not a variable is ever written.
  */
@@ -651,126 +650,6 @@ interstage_cross_validate_uniform_blocks(struct gl_shader_program *prog)
    return true;
 }
 
-/**
- * Validate that outputs from one stage match inputs of another
- */
-bool
-cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
-				 gl_shader *producer, gl_shader *consumer)
-{
-   glsl_symbol_table parameters;
-   /* FINISHME: Figure these out dynamically. */
-   const char *const producer_stage = "vertex";
-   const char *const consumer_stage = "fragment";
-
-   /* Find all shader outputs in the "producer" stage.
-    */
-   foreach_list(node, producer->ir) {
-      ir_variable *const var = ((ir_instruction *) node)->as_variable();
-
-      /* FINISHME: For geometry shaders, this should also look for inout
-       * FINISHME: variables.
-       */
-      if ((var == NULL) || (var->mode != ir_var_out))
-	 continue;
-
-      parameters.add_variable(var);
-   }
-
-
-   /* Find all shader inputs in the "consumer" stage.  Any variables that have
-    * matching outputs already in the symbol table must have the same type and
-    * qualifiers.
-    */
-   foreach_list(node, consumer->ir) {
-      ir_variable *const input = ((ir_instruction *) node)->as_variable();
-
-      /* FINISHME: For geometry shaders, this should also look for inout
-       * FINISHME: variables.
-       */
-      if ((input == NULL) || (input->mode != ir_var_in))
-	 continue;
-
-      ir_variable *const output = parameters.get_variable(input->name);
-      if (output != NULL) {
-	 /* Check that the types match between stages.
-	  */
-	 if (input->type != output->type) {
-	    /* 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(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(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(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;
-	 }
-      }
-   }
-
-   return true;
-}
-
 
 /**
  * Populates a shaders symbol table with all global declarations
@@ -1528,1010 +1407,6 @@ demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
 
 
 /**
- * Data structure tracking information about a transform feedback declaration
- * during linking.
- */
-class tfeedback_decl
-{
-public:
-   bool init(struct gl_context *ctx, struct gl_shader_program *prog,
-             const void *mem_ctx, const char *input);
-   static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);
-   bool assign_location(struct gl_context *ctx, struct gl_shader_program *prog,
-                        ir_variable *output_var);
-   unsigned get_num_outputs() const;
-   bool store(struct gl_context *ctx, struct gl_shader_program *prog,
-              struct gl_transform_feedback_info *info, unsigned buffer,
-              const unsigned max_outputs) const;
-   ir_variable *find_output_var(gl_shader_program *prog,
-                                gl_shader *producer) const;
-
-   bool is_next_buffer_separator() const
-   {
-      return this->next_buffer_separator;
-   }
-
-   bool is_varying() const
-   {
-      return !this->next_buffer_separator && !this->skip_components;
-   }
-
-   /**
-    * The total number of varying components taken up by this variable.  Only
-    * valid if assign_location() has been called.
-    */
-   unsigned num_components() const
-   {
-      if (this->is_clip_distance_mesa)
-         return this->size;
-      else
-         return this->vector_elements * this->matrix_columns * this->size;
-   }
-
-private:
-   /**
-    * The name that was supplied to glTransformFeedbackVaryings.  Used for
-    * error reporting and glGetTransformFeedbackVarying().
-    */
-   const char *orig_name;
-
-   /**
-    * The name of the variable, parsed from orig_name.
-    */
-   const char *var_name;
-
-   /**
-    * True if the declaration in orig_name represents an array.
-    */
-   bool is_subscripted;
-
-   /**
-    * If is_subscripted is true, the subscript that was specified in orig_name.
-    */
-   unsigned array_subscript;
-
-   /**
-    * True if the variable is gl_ClipDistance and the driver lowers
-    * gl_ClipDistance to gl_ClipDistanceMESA.
-    */
-   bool is_clip_distance_mesa;
-
-   /**
-    * The vertex shader output location that the linker assigned for this
-    * variable.  -1 if a location hasn't been assigned yet.
-    */
-   int location;
-
-   /**
-    * If non-zero, then this variable may be packed along with other variables
-    * into a single varying slot, so this offset should be applied when
-    * accessing components.  For example, an offset of 1 means that the x
-    * component of this variable is actually stored in component y of the
-    * location specified by \c location.
-    *
-    * Only valid if location != -1.
-    */
-   unsigned location_frac;
-
-   /**
-    * If location != -1, the number of vector elements in this variable, or 1
-    * if this variable is a scalar.
-    */
-   unsigned vector_elements;
-
-   /**
-    * If location != -1, the number of matrix columns in this variable, or 1
-    * if this variable is not a matrix.
-    */
-   unsigned matrix_columns;
-
-   /** Type of the varying returned by glGetTransformFeedbackVarying() */
-   GLenum type;
-
-   /**
-    * If location != -1, the size that should be returned by
-    * glGetTransformFeedbackVarying().
-    */
-   unsigned size;
-
-   /**
-    * How many components to skip. If non-zero, this is
-    * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3.
-    */
-   unsigned skip_components;
-
-   /**
-    * Whether this is gl_NextBuffer from ARB_transform_feedback3.
-    */
-   bool next_buffer_separator;
-};
-
-
-/**
- * Initialize this object based on a string that was passed to
- * glTransformFeedbackVaryings.  If there is a parse error, the error is
- * reported using linker_error(), and false is returned.
- */
-bool
-tfeedback_decl::init(struct gl_context *ctx, struct gl_shader_program *prog,
-                     const void *mem_ctx, const char *input)
-{
-   /* We don't have to be pedantic about what is a valid GLSL variable name,
-    * because any variable with an invalid name can't exist in the IR anyway.
-    */
-
-   this->location = -1;
-   this->orig_name = input;
-   this->is_clip_distance_mesa = false;
-   this->skip_components = 0;
-   this->next_buffer_separator = false;
-
-   if (ctx->Extensions.ARB_transform_feedback3) {
-      /* Parse gl_NextBuffer. */
-      if (strcmp(input, "gl_NextBuffer") == 0) {
-         this->next_buffer_separator = true;
-         return true;
-      }
-
-      /* Parse gl_SkipComponents. */
-      if (strcmp(input, "gl_SkipComponents1") == 0)
-         this->skip_components = 1;
-      else if (strcmp(input, "gl_SkipComponents2") == 0)
-         this->skip_components = 2;
-      else if (strcmp(input, "gl_SkipComponents3") == 0)
-         this->skip_components = 3;
-      else if (strcmp(input, "gl_SkipComponents4") == 0)
-         this->skip_components = 4;
-
-      if (this->skip_components)
-         return true;
-   }
-
-   /* Parse a declaration. */
-   const char *bracket = strrchr(input, '[');
-
-   if (bracket) {
-      this->var_name = ralloc_strndup(mem_ctx, input, bracket - input);
-      if (sscanf(bracket, "[%u]", &this->array_subscript) != 1) {
-         linker_error(prog, "Cannot parse transform feedback varying %s", input);
-         return false;
-      }
-      this->is_subscripted = true;
-   } else {
-      this->var_name = ralloc_strdup(mem_ctx, input);
-      this->is_subscripted = false;
-   }
-
-   /* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this
-    * class must behave specially to account for the fact that gl_ClipDistance
-    * is converted from a float[8] to a vec4[2].
-    */
-   if (ctx->ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
-       strcmp(this->var_name, "gl_ClipDistance") == 0) {
-      this->is_clip_distance_mesa = true;
-   }
-
-   return true;
-}
-
-
-/**
- * Determine whether two tfeedback_decl objects refer to the same variable and
- * array index (if applicable).
- */
-bool
-tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y)
-{
-   assert(x.is_varying() && y.is_varying());
-
-   if (strcmp(x.var_name, y.var_name) != 0)
-      return false;
-   if (x.is_subscripted != y.is_subscripted)
-      return false;
-   if (x.is_subscripted && x.array_subscript != y.array_subscript)
-      return false;
-   return true;
-}
-
-
-/**
- * Assign a location for this tfeedback_decl object based on the location
- * assignment in output_var.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-tfeedback_decl::assign_location(struct gl_context *ctx,
-                                struct gl_shader_program *prog,
-                                ir_variable *output_var)
-{
-   assert(this->is_varying());
-
-   if (output_var->type->is_array()) {
-      /* Array variable */
-      const unsigned matrix_cols =
-         output_var->type->fields.array->matrix_columns;
-      const unsigned vector_elements =
-         output_var->type->fields.array->vector_elements;
-      unsigned actual_array_size = this->is_clip_distance_mesa ?
-         prog->Vert.ClipDistanceArraySize : output_var->type->array_size();
-
-      if (this->is_subscripted) {
-         /* Check array bounds. */
-         if (this->array_subscript >= actual_array_size) {
-            linker_error(prog, "Transform feedback varying %s has index "
-                         "%i, but the array size is %u.",
-                         this->orig_name, this->array_subscript,
-                         actual_array_size);
-            return false;
-         }
-         if (this->is_clip_distance_mesa) {
-            this->location =
-               output_var->location + this->array_subscript / 4;
-            this->location_frac = this->array_subscript % 4;
-         } else {
-            unsigned fine_location
-               = output_var->location * 4 + output_var->location_frac;
-            unsigned array_elem_size = vector_elements * matrix_cols;
-            fine_location += array_elem_size * this->array_subscript;
-            this->location = fine_location / 4;
-            this->location_frac = fine_location % 4;
-         }
-         this->size = 1;
-      } else {
-         this->location = output_var->location;
-         this->location_frac = output_var->location_frac;
-         this->size = actual_array_size;
-      }
-      this->vector_elements = vector_elements;
-      this->matrix_columns = matrix_cols;
-      if (this->is_clip_distance_mesa)
-         this->type = GL_FLOAT;
-      else
-         this->type = output_var->type->fields.array->gl_type;
-   } else {
-      /* Regular variable (scalar, vector, or matrix) */
-      if (this->is_subscripted) {
-         linker_error(prog, "Transform feedback varying %s requested, "
-                      "but %s is not an array.",
-                      this->orig_name, this->var_name);
-         return false;
-      }
-      this->location = output_var->location;
-      this->location_frac = output_var->location_frac;
-      this->size = 1;
-      this->vector_elements = output_var->type->vector_elements;
-      this->matrix_columns = output_var->type->matrix_columns;
-      this->type = output_var->type->gl_type;
-   }
-
-   /* From GL_EXT_transform_feedback:
-    *   A program will fail to link if:
-    *
-    *   * the total number of components to capture in any varying
-    *     variable in <varyings> is greater than the constant
-    *     MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the
-    *     buffer mode is SEPARATE_ATTRIBS_EXT;
-    */
-   if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
-       this->num_components() >
-       ctx->Const.MaxTransformFeedbackSeparateComponents) {
-      linker_error(prog, "Transform feedback varying %s exceeds "
-                   "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.",
-                   this->orig_name);
-      return false;
-   }
-
-   return true;
-}
-
-
-unsigned
-tfeedback_decl::get_num_outputs() const
-{
-   if (!this->is_varying()) {
-      return 0;
-   }
-
-   return (this->num_components() + this->location_frac + 3)/4;
-}
-
-
-/**
- * Update gl_transform_feedback_info to reflect this tfeedback_decl.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-bool
-tfeedback_decl::store(struct gl_context *ctx, struct gl_shader_program *prog,
-                      struct gl_transform_feedback_info *info,
-                      unsigned buffer, const unsigned max_outputs) const
-{
-   assert(!this->next_buffer_separator);
-
-   /* Handle gl_SkipComponents. */
-   if (this->skip_components) {
-      info->BufferStride[buffer] += this->skip_components;
-      return true;
-   }
-
-   /* From GL_EXT_transform_feedback:
-    *   A program will fail to link if:
-    *
-    *     * the total number of components to capture is greater than
-    *       the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT
-    *       and the buffer mode is INTERLEAVED_ATTRIBS_EXT.
-    */
-   if (prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS &&
-       info->BufferStride[buffer] + this->num_components() >
-       ctx->Const.MaxTransformFeedbackInterleavedComponents) {
-      linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
-                   "limit has been exceeded.");
-      return false;
-   }
-
-   unsigned location = this->location;
-   unsigned location_frac = this->location_frac;
-   unsigned num_components = this->num_components();
-   while (num_components > 0) {
-      unsigned output_size = MIN2(num_components, 4 - location_frac);
-      assert(info->NumOutputs < max_outputs);
-      info->Outputs[info->NumOutputs].ComponentOffset = location_frac;
-      info->Outputs[info->NumOutputs].OutputRegister = location;
-      info->Outputs[info->NumOutputs].NumComponents = output_size;
-      info->Outputs[info->NumOutputs].OutputBuffer = buffer;
-      info->Outputs[info->NumOutputs].DstOffset = info->BufferStride[buffer];
-      ++info->NumOutputs;
-      info->BufferStride[buffer] += output_size;
-      num_components -= output_size;
-      location++;
-      location_frac = 0;
-   }
-
-   info->Varyings[info->NumVarying].Name = ralloc_strdup(prog, this->orig_name);
-   info->Varyings[info->NumVarying].Type = this->type;
-   info->Varyings[info->NumVarying].Size = this->size;
-   info->NumVarying++;
-
-   return true;
-}
-
-
-ir_variable *
-tfeedback_decl::find_output_var(gl_shader_program *prog,
-                                gl_shader *producer) const
-{
-   const char *name = this->is_clip_distance_mesa
-      ? "gl_ClipDistanceMESA" : this->var_name;
-   ir_variable *var = producer->symbols->get_variable(name);
-   if (var && var->mode == ir_var_out)
-      return var;
-
-   /* From GL_EXT_transform_feedback:
-    *   A program will fail to link if:
-    *
-    *   * any variable name specified in the <varyings> array is not
-    *     declared as an output in the geometry shader (if present) or
-    *     the vertex shader (if no geometry shader is present);
-    */
-   linker_error(prog, "Transform feedback varying %s undeclared.",
-                this->orig_name);
-   return NULL;
-}
-
-
-/**
- * Parse all the transform feedback declarations that were passed to
- * glTransformFeedbackVaryings() and store them in tfeedback_decl objects.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-static bool
-parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,
-                      const void *mem_ctx, unsigned num_names,
-                      char **varying_names, tfeedback_decl *decls)
-{
-   for (unsigned i = 0; i < num_names; ++i) {
-      if (!decls[i].init(ctx, prog, mem_ctx, varying_names[i]))
-         return false;
-
-      if (!decls[i].is_varying())
-         continue;
-
-      /* From GL_EXT_transform_feedback:
-       *   A program will fail to link if:
-       *
-       *   * any two entries in the <varyings> array specify the same varying
-       *     variable;
-       *
-       * We interpret this to mean "any two entries in the <varyings> array
-       * specify the same varying variable and array index", since transform
-       * feedback of arrays would be useless otherwise.
-       */
-      for (unsigned j = 0; j < i; ++j) {
-         if (!decls[j].is_varying())
-            continue;
-
-         if (tfeedback_decl::is_same(decls[i], decls[j])) {
-            linker_error(prog, "Transform feedback varying %s specified "
-                         "more than once.", varying_names[i]);
-            return false;
-         }
-      }
-   }
-   return true;
-}
-
-
-/**
- * Data structure recording the relationship between outputs of one shader
- * stage (the "producer") and inputs of another (the "consumer").
- */
-class varying_matches
-{
-public:
-   varying_matches(bool disable_varying_packing);
-   ~varying_matches();
-   void record(ir_variable *producer_var, ir_variable *consumer_var);
-   unsigned assign_locations();
-   void store_locations(unsigned producer_base, unsigned consumer_base) const;
-
-private:
-   /**
-    * If true, this driver disables varying packing, so all varyings need to
-    * be aligned on slot boundaries, and take up a number of slots equal to
-    * their number of matrix columns times their array size.
-    */
-   const bool disable_varying_packing;
-
-   /**
-    * Enum representing the order in which varyings are packed within a
-    * packing class.
-    *
-    * Currently we pack vec4's first, then vec2's, then scalar values, then
-    * vec3's.  This order ensures that the only vectors that are at risk of
-    * having to be "double parked" (split between two adjacent varying slots)
-    * are the vec3's.
-    */
-   enum packing_order_enum {
-      PACKING_ORDER_VEC4,
-      PACKING_ORDER_VEC2,
-      PACKING_ORDER_SCALAR,
-      PACKING_ORDER_VEC3,
-   };
-
-   static unsigned compute_packing_class(ir_variable *var);
-   static packing_order_enum compute_packing_order(ir_variable *var);
-   static int match_comparator(const void *x_generic, const void *y_generic);
-
-   /**
-    * Structure recording the relationship between a single producer output
-    * and a single consumer input.
-    */
-   struct match {
-      /**
-       * Packing class for this varying, computed by compute_packing_class().
-       */
-      unsigned packing_class;
-
-      /**
-       * Packing order for this varying, computed by compute_packing_order().
-       */
-      packing_order_enum packing_order;
-      unsigned num_components;
-
-      /**
-       * The output variable in the producer stage.
-       */
-      ir_variable *producer_var;
-
-      /**
-       * The input variable in the consumer stage.
-       */
-      ir_variable *consumer_var;
-
-      /**
-       * The location which has been assigned for this varying.  This is
-       * expressed in multiples of a float, with the first generic varying
-       * (i.e. the one referred to by VERT_RESULT_VAR0 or FRAG_ATTRIB_VAR0)
-       * represented by the value 0.
-       */
-      unsigned generic_location;
-   } *matches;
-
-   /**
-    * The number of elements in the \c matches array that are currently in
-    * use.
-    */
-   unsigned num_matches;
-
-   /**
-    * The number of elements that were set aside for the \c matches array when
-    * it was allocated.
-    */
-   unsigned matches_capacity;
-};
-
-
-varying_matches::varying_matches(bool disable_varying_packing)
-   : disable_varying_packing(disable_varying_packing)
-{
-   /* Note: this initial capacity is rather arbitrarily chosen to be large
-    * enough for many cases without wasting an unreasonable amount of space.
-    * varying_matches::record() will resize the array if there are more than
-    * this number of varyings.
-    */
-   this->matches_capacity = 8;
-   this->matches = (match *)
-      malloc(sizeof(*this->matches) * this->matches_capacity);
-   this->num_matches = 0;
-}
-
-
-varying_matches::~varying_matches()
-{
-   free(this->matches);
-}
-
-
-/**
- * Record the given producer/consumer variable pair in the list of variables
- * that should later be assigned locations.
- *
- * It is permissible for \c consumer_var to be NULL (this happens if a
- * variable is output by the producer and consumed by transform feedback, but
- * not consumed by the consumer).
- *
- * If \c producer_var has already been paired up with a consumer_var, or
- * producer_var is part of fixed pipeline functionality (and hence already has
- * a location assigned), this function has no effect.
- */
-void
-varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var)
-{
-   if (!producer_var->is_unmatched_generic_inout) {
-      /* Either a location already exists for this variable (since it is part
-       * of fixed functionality), or it has already been recorded as part of a
-       * previous match.
-       */
-      return;
-   }
-
-   if (this->num_matches == this->matches_capacity) {
-      this->matches_capacity *= 2;
-      this->matches = (match *)
-         realloc(this->matches,
-                 sizeof(*this->matches) * this->matches_capacity);
-   }
-   this->matches[this->num_matches].packing_class
-      = this->compute_packing_class(producer_var);
-   this->matches[this->num_matches].packing_order
-      = this->compute_packing_order(producer_var);
-   if (this->disable_varying_packing) {
-      unsigned slots = producer_var->type->is_array()
-         ? (producer_var->type->length
-            * producer_var->type->fields.array->matrix_columns)
-         : producer_var->type->matrix_columns;
-      this->matches[this->num_matches].num_components = 4 * slots;
-   } else {
-      this->matches[this->num_matches].num_components
-         = producer_var->type->component_slots();
-   }
-   this->matches[this->num_matches].producer_var = producer_var;
-   this->matches[this->num_matches].consumer_var = consumer_var;
-   this->num_matches++;
-   producer_var->is_unmatched_generic_inout = 0;
-   if (consumer_var)
-      consumer_var->is_unmatched_generic_inout = 0;
-}
-
-
-/**
- * Choose locations for all of the variable matches that were previously
- * passed to varying_matches::record().
- */
-unsigned
-varying_matches::assign_locations()
-{
-   /* Sort varying matches into an order that makes them easy to pack. */
-   qsort(this->matches, this->num_matches, sizeof(*this->matches),
-         &varying_matches::match_comparator);
-
-   unsigned generic_location = 0;
-
-   for (unsigned i = 0; i < this->num_matches; i++) {
-      /* Advance to the next slot if this varying has a different packing
-       * class than the previous one, and we're not already on a slot
-       * boundary.
-       */
-      if (i > 0 &&
-          this->matches[i - 1].packing_class
-          != this->matches[i].packing_class) {
-         generic_location = ALIGN(generic_location, 4);
-      }
-
-      this->matches[i].generic_location = generic_location;
-
-      generic_location += this->matches[i].num_components;
-   }
-
-   return (generic_location + 3) / 4;
-}
-
-
-/**
- * Update the producer and consumer shaders to reflect the locations
- * assignments that were made by varying_matches::assign_locations().
- */
-void
-varying_matches::store_locations(unsigned producer_base,
-                                 unsigned consumer_base) const
-{
-   for (unsigned i = 0; i < this->num_matches; i++) {
-      ir_variable *producer_var = this->matches[i].producer_var;
-      ir_variable *consumer_var = this->matches[i].consumer_var;
-      unsigned generic_location = this->matches[i].generic_location;
-      unsigned slot = generic_location / 4;
-      unsigned offset = generic_location % 4;
-
-      producer_var->location = producer_base + slot;
-      producer_var->location_frac = offset;
-      if (consumer_var) {
-         assert(consumer_var->location == -1);
-         consumer_var->location = consumer_base + slot;
-         consumer_var->location_frac = offset;
-      }
-   }
-}
-
-
-/**
- * Compute the "packing class" of the given varying.  This is an unsigned
- * integer with the property that two variables in the same packing class can
- * be safely backed into the same vec4.
- */
-unsigned
-varying_matches::compute_packing_class(ir_variable *var)
-{
-   /* In this initial implementation we conservatively assume that variables
-    * can only be packed if their base type (float/int/uint/bool) matches and
-    * their interpolation and centroid qualifiers match.
-    *
-    * TODO: relax these restrictions when the driver back-end permits.
-    */
-   unsigned packing_class = var->centroid ? 1 : 0;
-   packing_class *= 4;
-   packing_class += var->interpolation;
-   packing_class *= GLSL_TYPE_ERROR;
-   packing_class += var->type->get_scalar_type()->base_type;
-   return packing_class;
-}
-
-
-/**
- * Compute the "packing order" of the given varying.  This is a sort key we
- * use to determine when to attempt to pack the given varying relative to
- * other varyings in the same packing class.
- */
-varying_matches::packing_order_enum
-varying_matches::compute_packing_order(ir_variable *var)
-{
-   const glsl_type *element_type = var->type;
-
-   /* FINISHME: Support for "varying" records in GLSL 1.50. */
-   while (element_type->base_type == GLSL_TYPE_ARRAY) {
-      element_type = element_type->fields.array;
-   }
-
-   switch (element_type->vector_elements) {
-   case 1: return PACKING_ORDER_SCALAR;
-   case 2: return PACKING_ORDER_VEC2;
-   case 3: return PACKING_ORDER_VEC3;
-   case 4: return PACKING_ORDER_VEC4;
-   default:
-      assert(!"Unexpected value of vector_elements");
-      return PACKING_ORDER_VEC4;
-   }
-}
-
-
-/**
- * Comparison function passed to qsort() to sort varyings by packing_class and
- * then by packing_order.
- */
-int
-varying_matches::match_comparator(const void *x_generic, const void *y_generic)
-{
-   const match *x = (const match *) x_generic;
-   const match *y = (const match *) y_generic;
-
-   if (x->packing_class != y->packing_class)
-      return x->packing_class - y->packing_class;
-   return x->packing_order - y->packing_order;
-}
-
-
-/**
- * Is the given variable a varying variable to be counted against the
- * limit in ctx->Const.MaxVarying?
- * This includes variables such as texcoords, colors and generic
- * varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord.
- */
-static bool
-is_varying_var(GLenum shaderType, const ir_variable *var)
-{
-   /* Only fragment shaders will take a varying variable as an input */
-   if (shaderType == GL_FRAGMENT_SHADER &&
-       var->mode == ir_var_in) {
-      switch (var->location) {
-      case FRAG_ATTRIB_WPOS:
-      case FRAG_ATTRIB_FACE:
-      case FRAG_ATTRIB_PNTC:
-         return false;
-      default:
-         return true;
-      }
-   }
-   return false;
-}
-
-
-/**
- * Assign locations for all variables that are produced in one pipeline stage
- * (the "producer") and consumed in the next stage (the "consumer").
- *
- * Variables produced by the producer may also be consumed by transform
- * feedback.
- *
- * \param num_tfeedback_decls is the number of declarations indicating
- *        variables that may be consumed by transform feedback.
- *
- * \param tfeedback_decls is a pointer to an array of tfeedback_decl objects
- *        representing the result of parsing the strings passed to
- *        glTransformFeedbackVaryings().  assign_location() will be called for
- *        each of these objects that matches one of the outputs of the
- *        producer.
- *
- * When num_tfeedback_decls is nonzero, it is permissible for the consumer to
- * be NULL.  In this case, varying locations are assigned solely based on the
- * requirements of transform feedback.
- */
-bool
-assign_varying_locations(struct gl_context *ctx,
-			 void *mem_ctx,
-			 struct gl_shader_program *prog,
-			 gl_shader *producer, gl_shader *consumer,
-                         unsigned num_tfeedback_decls,
-                         tfeedback_decl *tfeedback_decls)
-{
-   /* FINISHME: Set dynamically when geometry shader support is added. */
-   const unsigned producer_base = VERT_RESULT_VAR0;
-   const unsigned consumer_base = FRAG_ATTRIB_VAR0;
-   varying_matches matches(ctx->Const.DisableVaryingPacking);
-
-   /* Operate in a total of three passes.
-    *
-    * 1. Assign locations for any matching inputs and outputs.
-    *
-    * 2. Mark output variables in the producer that do not have locations as
-    *    not being outputs.  This lets the optimizer eliminate them.
-    *
-    * 3. Mark input variables in the consumer that do not have locations as
-    *    not being inputs.  This lets the optimizer eliminate them.
-    */
-
-   foreach_list(node, producer->ir) {
-      ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
-
-      if ((output_var == NULL) || (output_var->mode != ir_var_out))
-	 continue;
-
-      ir_variable *input_var =
-	 consumer ? consumer->symbols->get_variable(output_var->name) : NULL;
-
-      if (input_var && input_var->mode != ir_var_in)
-         input_var = NULL;
-
-      if (input_var) {
-         matches.record(output_var, input_var);
-      }
-   }
-
-   for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-      if (!tfeedback_decls[i].is_varying())
-         continue;
-
-      ir_variable *output_var
-         = tfeedback_decls[i].find_output_var(prog, producer);
-
-      if (output_var == NULL)
-         return false;
-
-      if (output_var->is_unmatched_generic_inout) {
-         matches.record(output_var, NULL);
-      }
-   }
-
-   const unsigned slots_used = matches.assign_locations();
-   matches.store_locations(producer_base, consumer_base);
-
-   for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-      if (!tfeedback_decls[i].is_varying())
-         continue;
-
-      ir_variable *output_var
-         = tfeedback_decls[i].find_output_var(prog, producer);
-
-      if (!tfeedback_decls[i].assign_location(ctx, prog, output_var))
-         return false;
-   }
-
-   if (ctx->Const.DisableVaryingPacking) {
-      /* Transform feedback code assumes varyings are packed, so if the driver
-       * has disabled varying packing, make sure it does not support transform
-       * feedback.
-       */
-      assert(!ctx->Extensions.EXT_transform_feedback);
-   } else {
-      lower_packed_varyings(mem_ctx, producer_base, slots_used, ir_var_out,
-                            producer);
-      if (consumer) {
-         lower_packed_varyings(mem_ctx, consumer_base, slots_used, ir_var_in,
-                               consumer);
-      }
-   }
-
-   unsigned varying_vectors = 0;
-
-   if (consumer) {
-      foreach_list(node, consumer->ir) {
-         ir_variable *const var = ((ir_instruction *) node)->as_variable();
-
-         if ((var == NULL) || (var->mode != ir_var_in))
-            continue;
-
-         if (var->is_unmatched_generic_inout) {
-            if (prog->Version <= 120) {
-               /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
-                *
-                *     Only those varying variables used (i.e. read) in
-                *     the fragment shader executable must be written to
-                *     by the vertex shader executable; declaring
-                *     superfluous varying variables in a vertex shader is
-                *     permissible.
-                *
-                * We interpret this text as meaning that the VS must
-                * write the variable for the FS to read it.  See
-                * "glsl1-varying read but not written" in piglit.
-                */
-
-               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 if (is_varying_var(consumer->Type, var)) {
-            /* 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->IsES) {
-      if (varying_vectors > ctx->Const.MaxVarying) {
-         if (ctx->Const.GLSLSkipStrictMaxVaryingLimitCheck) {
-            linker_warning(prog, "shader uses too many varying vectors "
-                           "(%u > %u), but the driver will try to optimize "
-                           "them out; this is non-portable out-of-spec "
-                           "behavior\n",
-                           varying_vectors, ctx->Const.MaxVarying);
-         } else {
-            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) {
-         if (ctx->Const.GLSLSkipStrictMaxVaryingLimitCheck) {
-            linker_warning(prog, "shader uses too many varying components "
-                           "(%u > %u), but the driver will try to optimize "
-                           "them out; this is non-portable out-of-spec "
-                           "behavior\n",
-                           float_components, ctx->Const.MaxVarying * 4);
-         } else {
-            linker_error(prog, "shader uses too many varying components "
-                         "(%u > %u)\n",
-                         float_components, ctx->Const.MaxVarying * 4);
-            return false;
-         }
-      }
-   }
-
-   return true;
-}
-
-
-/**
- * Store transform feedback location assignments into
- * prog->LinkedTransformFeedback based on the data stored in tfeedback_decls.
- *
- * If an error occurs, the error is reported through linker_error() and false
- * is returned.
- */
-static bool
-store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
-                     unsigned num_tfeedback_decls,
-                     tfeedback_decl *tfeedback_decls)
-{
-   bool separate_attribs_mode =
-      prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
-
-   ralloc_free(prog->LinkedTransformFeedback.Varyings);
-   ralloc_free(prog->LinkedTransformFeedback.Outputs);
-
-   memset(&prog->LinkedTransformFeedback, 0,
-          sizeof(prog->LinkedTransformFeedback));
-
-   prog->LinkedTransformFeedback.Varyings =
-      rzalloc_array(prog,
-		    struct gl_transform_feedback_varying_info,
-		    num_tfeedback_decls);
-
-   unsigned num_outputs = 0;
-   for (unsigned i = 0; i < num_tfeedback_decls; ++i)
-      num_outputs += tfeedback_decls[i].get_num_outputs();
-
-   prog->LinkedTransformFeedback.Outputs =
-      rzalloc_array(prog,
-                    struct gl_transform_feedback_output,
-                    num_outputs);
-
-   unsigned num_buffers = 0;
-
-   if (separate_attribs_mode) {
-      /* GL_SEPARATE_ATTRIBS */
-      for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-         if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback,
-                                       num_buffers, num_outputs))
-            return false;
-
-         num_buffers++;
-      }
-   }
-   else {
-      /* GL_INVERLEAVED_ATTRIBS */
-      for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
-         if (tfeedback_decls[i].is_next_buffer_separator()) {
-            num_buffers++;
-            continue;
-         }
-
-         if (!tfeedback_decls[i].store(ctx, prog,
-                                       &prog->LinkedTransformFeedback,
-                                       num_buffers, num_outputs))
-            return false;
-      }
-      num_buffers++;
-   }
-
-   assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs);
-
-   prog->LinkedTransformFeedback.NumBuffers = num_buffers;
-   return true;
-}
-
-/**
  * Store the gl_FragDepth layout in the gl_shader_program struct.
  */
 static void
diff --git a/mesalib/src/glsl/linker.h b/mesalib/src/glsl/linker.h
index 7d2e98a15..67c7f3488 100644
--- a/mesalib/src/glsl/linker.h
+++ b/mesalib/src/glsl/linker.h
@@ -91,4 +91,13 @@ private:
    void recursion(const glsl_type *t, char **name, size_t name_length);
 };
 
+void
+linker_error(gl_shader_program *prog, const char *fmt, ...);
+
+void
+linker_warning(gl_shader_program *prog, const char *fmt, ...);
+
+unsigned
+count_attribute_slots(const glsl_type *t);
+
 #endif /* GLSL_LINKER_H */
diff --git a/mesalib/src/glsl/loop_controls.cpp b/mesalib/src/glsl/loop_controls.cpp
index 9acbadc50..79c820436 100644
--- a/mesalib/src/glsl/loop_controls.cpp
+++ b/mesalib/src/glsl/loop_controls.cpp
@@ -222,10 +222,10 @@ loop_control_visitor::visit_leave(ir_loop *ir)
 	    limit = cond->operands[0]->as_constant();
 
 	    switch (cmp) {
-	    case ir_binop_less:    cmp = ir_binop_gequal;  break;
-	    case ir_binop_greater: cmp = ir_binop_lequal;  break;
-	    case ir_binop_lequal:  cmp = ir_binop_greater; break;
-	    case ir_binop_gequal:  cmp = ir_binop_less;    break;
+	    case ir_binop_less:    cmp = ir_binop_greater; break;
+	    case ir_binop_greater: cmp = ir_binop_less;    break;
+	    case ir_binop_lequal:  cmp = ir_binop_gequal;  break;
+	    case ir_binop_gequal:  cmp = ir_binop_lequal;  break;
 	    default: assert(!"Should not get here.");
 	    }
 	 }
diff --git a/mesalib/src/glsl/lower_packed_varyings.cpp b/mesalib/src/glsl/lower_packed_varyings.cpp
index 09c551c4e..9e7f274b7 100644
--- a/mesalib/src/glsl/lower_packed_varyings.cpp
+++ b/mesalib/src/glsl/lower_packed_varyings.cpp
@@ -66,6 +66,10 @@
  * performance.  However, hopefully in most cases the performance loss will
  * either be absorbed by a later optimization pass, or it will be offset by
  * memory bandwidth savings (because fewer varyings are used).
+ *
+ * This lowering pass also packs flat floats, ints, and uints together, by
+ * using ivec4 as the base type of flat "varyings", and using appropriate
+ * casts to convert floats and uints into ints.
  */
 
 #include "glsl_symbol_table.h"
@@ -90,6 +94,8 @@ public:
    void run(exec_list *instructions);
 
 private:
+   ir_assignment *bitwise_assign_pack(ir_rvalue *lhs, ir_rvalue *rhs);
+   ir_assignment *bitwise_assign_unpack(ir_rvalue *lhs, ir_rvalue *rhs);
    unsigned lower_rvalue(ir_rvalue *rvalue, unsigned fine_location,
                          ir_variable *unpacked_var, const char *name);
    unsigned lower_arraylike(ir_rvalue *rvalue, unsigned array_size,
@@ -181,6 +187,75 @@ lower_packed_varyings_visitor::run(exec_list *instructions)
    }
 }
 
+
+/**
+ * Make an ir_assignment from \c rhs to \c lhs, performing appropriate
+ * bitcasts if necessary to match up types.
+ *
+ * This function is called when packing varyings.
+ */
+ir_assignment *
+lower_packed_varyings_visitor::bitwise_assign_pack(ir_rvalue *lhs,
+                                                   ir_rvalue *rhs)
+{
+   if (lhs->type->base_type != rhs->type->base_type) {
+      /* Since we only mix types in flat varyings, and we always store flat
+       * varyings as type ivec4, we need only produce conversions from (uint
+       * or float) to int.
+       */
+      assert(lhs->type->base_type == GLSL_TYPE_INT);
+      switch (rhs->type->base_type) {
+      case GLSL_TYPE_UINT:
+         rhs = new(this->mem_ctx)
+            ir_expression(ir_unop_u2i, lhs->type, rhs);
+         break;
+      case GLSL_TYPE_FLOAT:
+         rhs = new(this->mem_ctx)
+            ir_expression(ir_unop_bitcast_f2i, lhs->type, rhs);
+         break;
+      default:
+         assert(!"Unexpected type conversion while lowering varyings");
+         break;
+      }
+   }
+   return new(this->mem_ctx) ir_assignment(lhs, rhs);
+}
+
+
+/**
+ * Make an ir_assignment from \c rhs to \c lhs, performing appropriate
+ * bitcasts if necessary to match up types.
+ *
+ * This function is called when unpacking varyings.
+ */
+ir_assignment *
+lower_packed_varyings_visitor::bitwise_assign_unpack(ir_rvalue *lhs,
+                                                     ir_rvalue *rhs)
+{
+   if (lhs->type->base_type != rhs->type->base_type) {
+      /* Since we only mix types in flat varyings, and we always store flat
+       * varyings as type ivec4, we need only produce conversions from int to
+       * (uint or float).
+       */
+      assert(rhs->type->base_type == GLSL_TYPE_INT);
+      switch (lhs->type->base_type) {
+      case GLSL_TYPE_UINT:
+         rhs = new(this->mem_ctx)
+            ir_expression(ir_unop_i2u, lhs->type, rhs);
+         break;
+      case GLSL_TYPE_FLOAT:
+         rhs = new(this->mem_ctx)
+            ir_expression(ir_unop_bitcast_i2f, lhs->type, rhs);
+         break;
+      default:
+         assert(!"Unexpected type conversion while lowering varyings");
+         break;
+      }
+   }
+   return new(this->mem_ctx) ir_assignment(lhs, rhs);
+}
+
+
 /**
  * Recursively pack or unpack the given varying (or portion of a varying) by
  * traversing all of its constituent vectors.
@@ -262,12 +337,12 @@ lower_packed_varyings_visitor::lower_rvalue(ir_rvalue *rvalue,
       ir_swizzle *swizzle = new(this->mem_ctx)
          ir_swizzle(packed_deref, swizzle_values, components);
       if (this->mode == ir_var_out) {
-         ir_assignment *assignment = new(this->mem_ctx)
-            ir_assignment(swizzle, rvalue);
+         ir_assignment *assignment
+            = this->bitwise_assign_pack(swizzle, rvalue);
          this->main_instructions->push_tail(assignment);
       } else {
-         ir_assignment *assignment = new(this->mem_ctx)
-            ir_assignment(rvalue, swizzle);
+         ir_assignment *assignment
+            = this->bitwise_assign_unpack(rvalue, swizzle);
          this->main_instructions->push_head(assignment);
       }
       return fine_location + components;
@@ -306,8 +381,9 @@ lower_packed_varyings_visitor::lower_arraylike(ir_rvalue *rvalue,
  * If no packed varying has been created for the given varying location yet,
  * create it and add it to the shader before returning it.
  *
- * The newly created varying inherits its base type (float, uint, or int) and
- * interpolation parameters from \c unpacked_var.
+ * The newly created varying inherits its interpolation parameters from \c
+ * unpacked_var.  Its base type is ivec4 if we are lowering a flat varying,
+ * vec4 otherwise.
  */
 ir_variable *
 lower_packed_varyings_visitor::get_packed_varying(unsigned location,
@@ -318,8 +394,11 @@ lower_packed_varyings_visitor::get_packed_varying(unsigned location,
    assert(slot < locations_used);
    if (this->packed_varyings[slot] == NULL) {
       char *packed_name = ralloc_asprintf(this->mem_ctx, "packed:%s", name);
-      const glsl_type *packed_type = glsl_type::get_instance(
-            unpacked_var->type->get_scalar_type()->base_type, 4, 1);
+      const glsl_type *packed_type;
+      if (unpacked_var->interpolation == INTERP_QUALIFIER_FLAT)
+         packed_type = glsl_type::ivec4_type;
+      else
+         packed_type = glsl_type::vec4_type;
       ir_variable *packed_var = new(this->mem_ctx)
          ir_variable(packed_type, packed_name, this->mode);
       packed_var->centroid = unpacked_var->centroid;