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[mesa.git] / src / glsl / ast_to_hir.cpp
index 9e7496b4b431860f21db9e7fdd3bd438f2f414ce..cde7052b0514f938626cce3411d7d092082a428f 100644 (file)
@@ -60,7 +60,6 @@ void
 _mesa_ast_to_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state)
 {
    _mesa_glsl_initialize_variables(instructions, state);
-   _mesa_glsl_initialize_functions(state);
 
    state->symbols->language_version = state->language_version;
 
@@ -665,6 +664,7 @@ mark_whole_array_access(ir_rvalue *access)
 
 ir_rvalue *
 do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
+             const char *non_lvalue_description,
              ir_rvalue *lhs, ir_rvalue *rhs, bool is_initializer,
              YYLTYPE lhs_loc)
 {
@@ -672,23 +672,32 @@ do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
    bool error_emitted = (lhs->type->is_error() || rhs->type->is_error());
 
    if (!error_emitted) {
-      if (lhs->variable_referenced() != NULL
-          && lhs->variable_referenced()->read_only) {
+      if (non_lvalue_description != NULL) {
+         _mesa_glsl_error(&lhs_loc, state,
+                          "assignment to %s",
+                         non_lvalue_description);
+        error_emitted = true;
+      } else if (lhs->variable_referenced() != NULL
+                && lhs->variable_referenced()->read_only) {
          _mesa_glsl_error(&lhs_loc, state,
                           "assignment to read-only variable '%s'",
                           lhs->variable_referenced()->name);
          error_emitted = true;
 
+      } else if (state->language_version <= 110 && lhs->type->is_array()) {
+        /* From page 32 (page 38 of the PDF) of the GLSL 1.10 spec:
+         *
+         *    "Other binary or unary expressions, non-dereferenced
+         *     arrays, function names, swizzles with repeated fields,
+         *     and constants cannot be l-values."
+         */
+        _mesa_glsl_error(&lhs_loc, state, "whole array assignment is not "
+                         "allowed in GLSL 1.10 or GLSL ES 1.00.");
+        error_emitted = true;
       } else if (!lhs->is_lvalue()) {
         _mesa_glsl_error(& lhs_loc, state, "non-lvalue in assignment");
         error_emitted = true;
       }
-
-      if (state->es_shader && lhs->type->is_array()) {
-        _mesa_glsl_error(&lhs_loc, state, "whole array assignment is not "
-                         "allowed in GLSL ES 1.00.");
-        error_emitted = true;
-      }
    }
 
    ir_rvalue *new_rhs =
@@ -723,6 +732,7 @@ do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
                                                   rhs->type->array_size());
         d->type = var->type;
       }
+      mark_whole_array_access(rhs);
       mark_whole_array_access(lhs);
    }
 
@@ -765,11 +775,6 @@ get_lvalue_copy(exec_list *instructions, ir_rvalue *lvalue)
    instructions->push_tail(new(ctx) ir_assignment(new(ctx) ir_dereference_variable(var),
                                                  lvalue, NULL));
 
-   /* Once we've created this temporary, mark it read only so it's no
-    * longer considered an lvalue.
-    */
-   var->read_only = true;
-
    return new(ctx) ir_dereference_variable(var);
 }
 
@@ -893,6 +898,66 @@ get_scalar_boolean_operand(exec_list *instructions,
    return new(ctx) ir_constant(true);
 }
 
+/**
+ * If name refers to a builtin array whose maximum allowed size is less than
+ * size, report an error and return true.  Otherwise return false.
+ */
+static bool
+check_builtin_array_max_size(const char *name, unsigned size,
+                             YYLTYPE loc, struct _mesa_glsl_parse_state *state)
+{
+   if ((strcmp("gl_TexCoord", name) == 0)
+       && (size > state->Const.MaxTextureCoords)) {
+      /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
+       *
+       *     "The size [of gl_TexCoord] can be at most
+       *     gl_MaxTextureCoords."
+       */
+      _mesa_glsl_error(&loc, state, "`gl_TexCoord' array size cannot "
+                       "be larger than gl_MaxTextureCoords (%u)\n",
+                       state->Const.MaxTextureCoords);
+      return true;
+   } else if (strcmp("gl_ClipDistance", name) == 0
+              && size > state->Const.MaxClipPlanes) {
+      /* From section 7.1 (Vertex Shader Special Variables) of the
+       * GLSL 1.30 spec:
+       *
+       *   "The gl_ClipDistance array is predeclared as unsized and
+       *   must be sized by the shader either redeclaring it with a
+       *   size or indexing it only with integral constant
+       *   expressions. ... The size can be at most
+       *   gl_MaxClipDistances."
+       */
+      _mesa_glsl_error(&loc, state, "`gl_ClipDistance' array size cannot "
+                       "be larger than gl_MaxClipDistances (%u)\n",
+                       state->Const.MaxClipPlanes);
+      return true;
+   }
+   return false;
+}
+
+/**
+ * Create the constant 1, of a which is appropriate for incrementing and
+ * decrementing values of the given GLSL type.  For example, if type is vec4,
+ * this creates a constant value of 1.0 having type float.
+ *
+ * If the given type is invalid for increment and decrement operators, return
+ * a floating point 1--the error will be detected later.
+ */
+static ir_rvalue *
+constant_one_for_inc_dec(void *ctx, const glsl_type *type)
+{
+   switch (type->base_type) {
+   case GLSL_TYPE_UINT:
+      return new(ctx) ir_constant((unsigned) 1);
+   case GLSL_TYPE_INT:
+      return new(ctx) ir_constant(1);
+   default:
+   case GLSL_TYPE_FLOAT:
+      return new(ctx) ir_constant(1.0f);
+   }
+}
+
 ir_rvalue *
 ast_expression::hir(exec_list *instructions,
                    struct _mesa_glsl_parse_state *state)
@@ -966,7 +1031,9 @@ ast_expression::hir(exec_list *instructions,
       op[0] = this->subexpressions[0]->hir(instructions, state);
       op[1] = this->subexpressions[1]->hir(instructions, state);
 
-      result = do_assignment(instructions, state, op[0], op[1], false,
+      result = do_assignment(instructions, state,
+                            this->subexpressions[0]->non_lvalue_description,
+                            op[0], op[1], false,
                             this->subexpressions[0]->get_location());
       error_emitted = result->type->is_error();
       break;
@@ -1120,7 +1187,7 @@ ast_expression::hir(exec_list *instructions,
         error_emitted = true;
       }
 
-      type = op[0]->type;
+      type = error_emitted ? glsl_type::error_type : op[0]->type;
       result = new(ctx) ir_expression(ir_unop_bit_not, type, op[0], NULL);
       break;
 
@@ -1246,6 +1313,7 @@ ast_expression::hir(exec_list *instructions,
                                                   op[0], op[1]);
 
       result = do_assignment(instructions, state,
+                            this->subexpressions[0]->non_lvalue_description,
                             op[0]->clone(ctx, NULL), temp_rhs, false,
                             this->subexpressions[0]->get_location());
       error_emitted = (op[0]->type->is_error());
@@ -1271,6 +1339,7 @@ ast_expression::hir(exec_list *instructions,
                                        op[0], op[1]);
 
       result = do_assignment(instructions, state,
+                            this->subexpressions[0]->non_lvalue_description,
                             op[0]->clone(ctx, NULL), temp_rhs, false,
                             this->subexpressions[0]->get_location());
       error_emitted = type->is_error();
@@ -1285,8 +1354,9 @@ ast_expression::hir(exec_list *instructions,
                                &loc);
       ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper],
                                                    type, op[0], op[1]);
-      result = do_assignment(instructions, state, op[0]->clone(ctx, NULL),
-                             temp_rhs, false,
+      result = do_assignment(instructions, state,
+                            this->subexpressions[0]->non_lvalue_description,
+                            op[0]->clone(ctx, NULL), temp_rhs, false,
                              this->subexpressions[0]->get_location());
       error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
       break;
@@ -1301,8 +1371,9 @@ ast_expression::hir(exec_list *instructions,
                                    state, &loc);
       ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper],
                                                    type, op[0], op[1]);
-      result = do_assignment(instructions, state, op[0]->clone(ctx, NULL),
-                             temp_rhs, false,
+      result = do_assignment(instructions, state,
+                            this->subexpressions[0]->non_lvalue_description,
+                            op[0]->clone(ctx, NULL), temp_rhs, false,
                              this->subexpressions[0]->get_location());
       error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
       break;
@@ -1399,11 +1470,11 @@ ast_expression::hir(exec_list *instructions,
 
    case ast_pre_inc:
    case ast_pre_dec: {
+      this->non_lvalue_description = (this->oper == ast_pre_inc)
+        ? "pre-increment operation" : "pre-decrement operation";
+
       op[0] = this->subexpressions[0]->hir(instructions, state);
-      if (op[0]->type->base_type == GLSL_TYPE_FLOAT)
-        op[1] = new(ctx) ir_constant(1.0f);
-      else
-        op[1] = new(ctx) ir_constant(1);
+      op[1] = constant_one_for_inc_dec(ctx, op[0]->type);
 
       type = arithmetic_result_type(op[0], op[1], false, state, & loc);
 
@@ -1412,6 +1483,7 @@ ast_expression::hir(exec_list *instructions,
                                        op[0], op[1]);
 
       result = do_assignment(instructions, state,
+                            this->subexpressions[0]->non_lvalue_description,
                             op[0]->clone(ctx, NULL), temp_rhs, false,
                             this->subexpressions[0]->get_location());
       error_emitted = op[0]->type->is_error();
@@ -1420,11 +1492,10 @@ ast_expression::hir(exec_list *instructions,
 
    case ast_post_inc:
    case ast_post_dec: {
+      this->non_lvalue_description = (this->oper == ast_post_inc)
+        ? "post-increment operation" : "post-decrement operation";
       op[0] = this->subexpressions[0]->hir(instructions, state);
-      if (op[0]->type->base_type == GLSL_TYPE_FLOAT)
-        op[1] = new(ctx) ir_constant(1.0f);
-      else
-        op[1] = new(ctx) ir_constant(1);
+      op[1] = constant_one_for_inc_dec(ctx, op[0]->type);
 
       error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
 
@@ -1440,6 +1511,7 @@ ast_expression::hir(exec_list *instructions,
       result = get_lvalue_copy(instructions, op[0]->clone(ctx, NULL));
 
       (void)do_assignment(instructions, state,
+                         this->subexpressions[0]->non_lvalue_description,
                          op[0]->clone(ctx, NULL), temp_rhs, false,
                          this->subexpressions[0]->get_location());
 
@@ -1550,8 +1622,15 @@ ast_expression::hir(exec_list *instructions,
             * FINISHME: array access limits be added to ir_dereference?
             */
            ir_variable *const v = array->whole_variable_referenced();
-           if ((v != NULL) && (unsigned(idx) > v->max_array_access))
+           if ((v != NULL) && (unsigned(idx) > v->max_array_access)) {
               v->max_array_access = idx;
+
+               /* Check whether this access will, as a side effect, implicitly
+                * cause the size of a built-in array to be too large.
+                */
+               if (check_builtin_array_max_size(v->name, idx+1, loc, state))
+                  error_emitted = true;
+            }
         }
       } else if (array->type->array_size() == 0) {
         _mesa_glsl_error(&loc, state, "unsized array index must be constant");
@@ -1763,7 +1842,17 @@ process_array_type(YYLTYPE *loc, const glsl_type *base, ast_node *array_size,
 {
    unsigned length = 0;
 
-   /* FINISHME: Reject delcarations of multidimensional arrays. */
+   /* From page 19 (page 25) of the GLSL 1.20 spec:
+    *
+    *     "Only one-dimensional arrays may be declared."
+    */
+   if (base->is_array()) {
+      _mesa_glsl_error(loc, state,
+                      "invalid array of `%s' (only one-dimensional arrays "
+                      "may be declared)",
+                      base->name);
+      return glsl_type::error_type;
+   }
 
    if (array_size != NULL) {
       exec_list dummy_instructions;
@@ -1913,11 +2002,36 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
    }
 
    if (qual->flags.q.flat)
-      var->interpolation = ir_var_flat;
+      var->interpolation = INTERP_QUALIFIER_FLAT;
    else if (qual->flags.q.noperspective)
-      var->interpolation = ir_var_noperspective;
+      var->interpolation = INTERP_QUALIFIER_NOPERSPECTIVE;
+   else if (qual->flags.q.smooth)
+      var->interpolation = INTERP_QUALIFIER_SMOOTH;
    else
-      var->interpolation = ir_var_smooth;
+      var->interpolation = INTERP_QUALIFIER_NONE;
+
+   if (var->interpolation != INTERP_QUALIFIER_NONE &&
+       !(state->target == vertex_shader && var->mode == ir_var_out) &&
+       !(state->target == fragment_shader && var->mode == ir_var_in)) {
+      const char *qual_string = NULL;
+      switch (var->interpolation) {
+      case INTERP_QUALIFIER_FLAT:
+        qual_string = "flat";
+        break;
+      case INTERP_QUALIFIER_NOPERSPECTIVE:
+        qual_string = "noperspective";
+        break;
+      case INTERP_QUALIFIER_SMOOTH:
+        qual_string = "smooth";
+        break;
+      }
+
+      _mesa_glsl_error(loc, state,
+                      "interpolation qualifier `%s' can only be applied to "
+                      "vertex shader outputs and fragment shader inputs.",
+                      qual_string);
+
+   }
 
    var->pixel_center_integer = qual->flags.q.pixel_center_integer;
    var->origin_upper_left = qual->flags.q.origin_upper_left;
@@ -2013,6 +2127,7 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
     * The following extension do not allow the deprecated keywords:
     *
     *    GL_AMD_conservative_depth
+    *    GL_ARB_conservative_depth
     *    GL_ARB_gpu_shader5
     *    GL_ARB_separate_shader_objects
     *    GL_ARB_tesselation_shader
@@ -2045,9 +2160,11 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
       + qual->flags.q.depth_less
       + qual->flags.q.depth_unchanged;
    if (depth_layout_count > 0
-       && !state->AMD_conservative_depth_enable) {
+       && !state->AMD_conservative_depth_enable
+       && !state->ARB_conservative_depth_enable) {
        _mesa_glsl_error(loc, state,
-                        "extension GL_AMD_conservative_depth must be enabled "
+                        "extension GL_AMD_conservative_depth or "
+                        "GL_ARB_conservative_depth must be enabled "
                        "to use depth layout qualifiers");
    } else if (depth_layout_count > 0
               && strcmp(var->name, "gl_FragDepth") != 0) {
@@ -2070,10 +2187,6 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
        var->depth_layout = ir_depth_layout_unchanged;
    else
        var->depth_layout = ir_depth_layout_none;
-
-   if (var->type->is_array() && state->language_version != 110) {
-      var->array_lvalue = true;
-   }
 }
 
 /**
@@ -2121,18 +2234,9 @@ get_variable_being_redeclared(ir_variable *var, ast_declaration *decl,
        * FINISHME: required or not.
        */
 
-      /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
-       *
-       *     "The size [of gl_TexCoord] can be at most
-       *     gl_MaxTextureCoords."
-       */
       const unsigned size = unsigned(var->type->array_size());
-      if ((strcmp("gl_TexCoord", var->name) == 0)
-         && (size > state->Const.MaxTextureCoords)) {
-        _mesa_glsl_error(& loc, state, "`gl_TexCoord' array size cannot "
-                         "be larger than gl_MaxTextureCoords (%u)\n",
-                         state->Const.MaxTextureCoords);
-      } else if ((size > 0) && (size <= earlier->max_array_access)) {
+      check_builtin_array_max_size(var->name, size, loc, state);
+      if ((size > 0) && (size <= earlier->max_array_access)) {
         _mesa_glsl_error(& loc, state, "array size must be > %u due to "
                          "previous access",
                          earlier->max_array_access);
@@ -2173,7 +2277,8 @@ get_variable_being_redeclared(ir_variable *var, ast_declaration *decl,
       earlier->interpolation = var->interpolation;
 
       /* Layout qualifiers for gl_FragDepth. */
-   } else if (state->AMD_conservative_depth_enable
+   } else if ((state->AMD_conservative_depth_enable ||
+               state->ARB_conservative_depth_enable)
              && strcmp(var->name, "gl_FragDepth") == 0
              && earlier->type == var->type
              && earlier->mode == var->mode) {
@@ -2297,12 +2402,16 @@ process_initializer(ir_variable *var, ast_declaration *decl,
       const glsl_type *initializer_type;
       if (!type->qualifier.flags.q.uniform) {
         result = do_assignment(initializer_instructions, state,
+                               NULL,
                                lhs, rhs, true,
                                type->get_location());
         initializer_type = result->type;
       } else
         initializer_type = rhs->type;
 
+      var->constant_initializer = rhs->constant_expression_value();
+      var->has_initializer = true;
+
       /* If the declared variable is an unsized array, it must inherrit
        * its full type from the initializer.  A declaration such as
        *
@@ -2407,14 +2516,32 @@ ast_declarator_list::hir(exec_list *instructions,
 
    decl_type = this->type->specifier->glsl_type(& type_name, state);
    if (this->declarations.is_empty()) {
-      if (decl_type != NULL) {
-        /* Warn if this empty declaration is not for declaring a structure.
-         */
-        if (this->type->specifier->structure == NULL) {
+      /* If there is no structure involved in the program text, there are two
+       * possible scenarios:
+       *
+       * - The program text contained something like 'vec4;'.  This is an
+       *   empty declaration.  It is valid but weird.  Emit a warning.
+       *
+       * - The program text contained something like 'S;' and 'S' is not the
+       *   name of a known structure type.  This is both invalid and weird.
+       *   Emit an error.
+       *
+       * Note that if decl_type is NULL and there is a structure involved,
+       * there must have been some sort of error with the structure.  In this
+       * case we assume that an error was already generated on this line of
+       * code for the structure.  There is no need to generate an additional,
+       * confusing error.
+       */
+      assert(this->type->specifier->structure == NULL || decl_type != NULL
+            || state->error);
+      if (this->type->specifier->structure == NULL) {
+        if (decl_type != NULL) {
            _mesa_glsl_warning(&loc, state, "empty declaration");
+        } else {
+           _mesa_glsl_error(&loc, state,
+                            "invalid type `%s' in empty declaration",
+                            type_name);
         }
-      } else {
-           _mesa_glsl_error(& loc, state, "incomplete declaration");
       }
    }
 
@@ -2442,6 +2569,8 @@ ast_declarator_list::hir(exec_list *instructions,
       if (decl->is_array) {
         var_type = process_array_type(&loc, decl_type, decl->array_size,
                                       state);
+        if (var_type->is_error())
+           continue;
       } else {
         var_type = decl_type;
       }
@@ -2594,7 +2723,7 @@ ast_declarator_list::hir(exec_list *instructions,
           && state->current_function == NULL
           && var->type->is_integer()
           && var->mode == ir_var_out
-          && var->interpolation != ir_var_flat) {
+          && var->interpolation != INTERP_QUALIFIER_FLAT) {
 
          _mesa_glsl_error(&loc, state, "If a vertex output is an integer, "
                           "then it must be qualified with 'flat'");
@@ -2767,6 +2896,18 @@ ast_declarator_list::hir(exec_list *instructions,
            _mesa_glsl_error(& loc, state,
                             "identifier `%s' uses reserved `gl_' prefix",
                             decl->identifier);
+        else if (strstr(decl->identifier, "__")) {
+           /* From page 14 (page 20 of the PDF) of the GLSL 1.10
+            * spec:
+            *
+            *     "In addition, all identifiers containing two
+            *      consecutive underscores (__) are reserved as
+            *      possible future keywords."
+            */
+           _mesa_glsl_error(& loc, state,
+                            "identifier `%s' uses reserved `__' string",
+                            decl->identifier);
+        }
 
         /* Add the variable to the symbol table.  Note that the initializer's
          * IR was already processed earlier (though it hasn't been emitted
@@ -2871,7 +3012,7 @@ ast_parameter_declarator::hir(exec_list *instructions,
       type = process_array_type(&loc, type, this->array_size, state);
    }
 
-   if (type->array_size() == 0) {
+   if (!type->is_error() && type->array_size() == 0) {
       _mesa_glsl_error(&loc, state, "arrays passed as parameters must have "
                       "a declared size.");
       type = glsl_type::error_type;
@@ -2897,6 +3038,26 @@ ast_parameter_declarator::hir(exec_list *instructions,
       type = glsl_type::error_type;
    }
 
+   /* From page 39 (page 45 of the PDF) of the GLSL 1.10 spec:
+    *
+    *    "When calling a function, expressions that do not evaluate to
+    *     l-values cannot be passed to parameters declared as out or inout."
+    *
+    * From page 32 (page 38 of the PDF) of the GLSL 1.10 spec:
+    *
+    *    "Other binary or unary expressions, non-dereferenced arrays,
+    *     function names, swizzles with repeated fields, and constants
+    *     cannot be l-values."
+    *
+    * So for GLSL 1.10, passing an array as an out or inout parameter is not
+    * allowed.  This restriction is removed in GLSL 1.20, and in GLSL ES.
+    */
+   if ((var->mode == ir_var_inout || var->mode == ir_var_out)
+       && type->is_array() && state->language_version == 110) {
+      _mesa_glsl_error(&loc, state, "Arrays cannot be out or inout parameters in GLSL 1.10");
+      type = glsl_type::error_type;
+   }
+
    instructions->push_tail(var);
 
    /* Parameter declarations do not have r-values.
@@ -2958,6 +3119,12 @@ ast_function::hir(exec_list *instructions,
 
    const char *const name = identifier;
 
+   /* New functions are always added to the top-level IR instruction stream,
+    * so this instruction list pointer is ignored.  See also emit_function
+    * (called below).
+    */
+   (void) instructions;
+
    /* From page 21 (page 27 of the PDF) of the GLSL 1.20 spec,
     *
     *   "Function declarations (prototypes) cannot occur inside of functions;
@@ -3230,34 +3397,49 @@ ast_jump_statement::hir(exec_list *instructions,
 
    case ast_break:
    case ast_continue:
-      /* FINISHME: Handle switch-statements.  They cannot contain 'continue',
-       * FINISHME: and they use a different IR instruction for 'break'.
-       */
-      /* FINISHME: Correctly handle the nesting.  If a switch-statement is
-       * FINISHME: inside a loop, a 'continue' is valid and will bind to the
-       * FINISHME: loop.
-       */
-      if (state->loop_or_switch_nesting == NULL) {
+      if (mode == ast_continue &&
+         state->loop_nesting_ast == NULL) {
         YYLTYPE loc = this->get_location();
 
         _mesa_glsl_error(& loc, state,
-                         "`%s' may only appear in a loop",
-                         (mode == ast_break) ? "break" : "continue");
-      } else {
-        ir_loop *const loop = state->loop_or_switch_nesting->as_loop();
+                         "continue may only appear in a loop");
+      } else if (mode == ast_break &&
+                state->loop_nesting_ast == NULL &&
+                state->switch_nesting_ast == NULL) {
+        YYLTYPE loc = this->get_location();
 
-        /* Inline the for loop expression again, since we don't know
-         * where near the end of the loop body the normal copy of it
+        _mesa_glsl_error(& loc, state,
+                         "break may only appear in a loop or a switch");
+      } else {
+        /* For a loop, inline the for loop expression again,
+         * since we don't know where near the end of
+         * the loop body the normal copy of it
          * is going to be placed.
          */
-        if (mode == ast_continue &&
-            state->loop_or_switch_nesting_ast->rest_expression) {
-           state->loop_or_switch_nesting_ast->rest_expression->hir(instructions,
-                                                                   state);
+        if (state->loop_nesting_ast != NULL &&
+            mode == ast_continue &&
+            state->loop_nesting_ast->rest_expression) {
+           state->loop_nesting_ast->rest_expression->hir(instructions,
+                                                         state);
         }
 
-        if (loop != NULL) {
-           ir_loop_jump *const jump =
+        if (state->is_switch_innermost &&
+            mode == ast_break) {
+           /* Force break out of switch by setting is_break switch state.
+            */
+           ir_variable *const is_break_var = state->is_break_var;
+           ir_dereference_variable *const deref_is_break_var =
+              new(ctx) ir_dereference_variable(is_break_var);
+           ir_constant *const true_val = new(ctx) ir_constant(true);
+           ir_assignment *const set_break_var =
+              new(ctx) ir_assignment(deref_is_break_var,
+                                     true_val,
+                                     NULL);
+           
+           instructions->push_tail(set_break_var);
+        }
+        else {
+           ir_loop_jump *const jump = 
               new(ctx) ir_loop_jump((mode == ast_break)
                                     ? ir_loop_jump::jump_break
                                     : ir_loop_jump::jump_continue);
@@ -3320,6 +3502,243 @@ ast_selection_statement::hir(exec_list *instructions,
 }
 
 
+ir_rvalue *
+ast_switch_statement::hir(exec_list *instructions,
+                         struct _mesa_glsl_parse_state *state)
+{
+   void *ctx = state;
+
+   ir_rvalue *const test_expression =
+      this->test_expression->hir(instructions, state);
+
+   /* From page 66 (page 55 of the PDF) of the GLSL 1.50 spec:
+    *
+    *    "The type of init-expression in a switch statement must be a 
+    *     scalar integer." 
+    *
+    * The checks are separated so that higher quality diagnostics can be
+    * generated for cases where the rule is violated.
+    */
+   if (!test_expression->type->is_integer()) {
+      YYLTYPE loc = this->test_expression->get_location();
+
+      _mesa_glsl_error(& loc,
+                      state,
+                      "switch-statement expression must be scalar "
+                      "integer");
+   }
+
+   /* Track the switch-statement nesting in a stack-like manner.
+    */
+   ir_variable *saved_test_var = state->test_var;
+   ir_variable *saved_is_fallthru_var = state->is_fallthru_var;
+   
+   bool save_is_switch_innermost = state->is_switch_innermost;
+   ast_switch_statement *saved_nesting_ast = state->switch_nesting_ast;
+
+   state->is_switch_innermost = true;
+   state->switch_nesting_ast = this;
+
+   /* Initalize is_fallthru state to false.
+    */
+   ir_rvalue *const is_fallthru_val = new (ctx) ir_constant(false);
+   state->is_fallthru_var = new(ctx) ir_variable(glsl_type::bool_type,
+                                               "switch_is_fallthru_tmp",
+                                               ir_var_temporary);
+   instructions->push_tail(state->is_fallthru_var);
+
+   ir_dereference_variable *deref_is_fallthru_var =
+      new(ctx) ir_dereference_variable(state->is_fallthru_var);
+   instructions->push_tail(new(ctx) ir_assignment(deref_is_fallthru_var,
+                                                 is_fallthru_val,
+                                                 NULL));
+
+   /* Initalize is_break state to false.
+    */
+   ir_rvalue *const is_break_val = new (ctx) ir_constant(false);
+   state->is_break_var = new(ctx) ir_variable(glsl_type::bool_type,
+                                             "switch_is_break_tmp",
+                                             ir_var_temporary);
+   instructions->push_tail(state->is_break_var);
+
+   ir_dereference_variable *deref_is_break_var =
+      new(ctx) ir_dereference_variable(state->is_break_var);
+   instructions->push_tail(new(ctx) ir_assignment(deref_is_break_var,
+                                                 is_break_val,
+                                                 NULL));
+
+   /* Cache test expression.
+    */
+   test_to_hir(instructions, state);
+   
+   /* Emit code for body of switch stmt.
+    */
+   body->hir(instructions, state);
+
+   /* Restore previous nesting before returning.
+    */
+   state->switch_nesting_ast = saved_nesting_ast;
+   state->is_switch_innermost = save_is_switch_innermost;
+
+   state->test_var = saved_test_var;
+   state->is_fallthru_var = saved_is_fallthru_var;
+
+   /* Switch statements do not have r-values.
+    */
+   return NULL;
+}
+
+
+void
+ast_switch_statement::test_to_hir(exec_list *instructions,
+                                 struct _mesa_glsl_parse_state *state)
+{
+   void *ctx = state;
+
+   /* Cache value of test expression.
+    */
+   ir_rvalue *const test_val =
+      test_expression->hir(instructions,
+                          state);
+
+   state->test_var = new(ctx) ir_variable(glsl_type::int_type,
+                                         "switch_test_tmp",
+                                         ir_var_temporary);
+   ir_dereference_variable *deref_test_var =
+      new(ctx) ir_dereference_variable(state->test_var);
+
+   instructions->push_tail(state->test_var);
+   instructions->push_tail(new(ctx) ir_assignment(deref_test_var,
+                                                 test_val,
+                                                 NULL));
+}
+
+
+ir_rvalue *
+ast_switch_body::hir(exec_list *instructions,
+                    struct _mesa_glsl_parse_state *state)
+{
+   if (stmts != NULL)
+      stmts->hir(instructions, state);
+      
+   /* Switch bodies do not have r-values.
+    */
+   return NULL;
+}
+
+
+ir_rvalue *
+ast_case_statement_list::hir(exec_list *instructions,
+                            struct _mesa_glsl_parse_state *state)
+{
+   foreach_list_typed (ast_case_statement, case_stmt, link, & this->cases)
+      case_stmt->hir(instructions, state);
+         
+   /* Case statements do not have r-values.
+    */
+   return NULL;
+}
+
+
+ir_rvalue *
+ast_case_statement::hir(exec_list *instructions,
+                       struct _mesa_glsl_parse_state *state)
+{
+   labels->hir(instructions, state);
+   
+   /* Conditionally set fallthru state based on break state.
+    */
+   ir_constant *const false_val = new(state) ir_constant(false);
+   ir_dereference_variable *const deref_is_fallthru_var =
+      new(state) ir_dereference_variable(state->is_fallthru_var);
+   ir_dereference_variable *const deref_is_break_var =
+      new(state) ir_dereference_variable(state->is_break_var);
+   ir_assignment *const reset_fallthru_on_break =
+      new(state) ir_assignment(deref_is_fallthru_var,
+                              false_val,
+                              deref_is_break_var);
+   instructions->push_tail(reset_fallthru_on_break);
+
+   /* Guard case statements depending on fallthru state.
+    */
+   ir_dereference_variable *const deref_fallthru_guard =
+      new(state) ir_dereference_variable(state->is_fallthru_var);
+   ir_if *const test_fallthru = new(state) ir_if(deref_fallthru_guard);
+   
+   foreach_list_typed (ast_node, stmt, link, & this->stmts)
+      stmt->hir(& test_fallthru->then_instructions, state);
+
+   instructions->push_tail(test_fallthru);
+         
+   /* Case statements do not have r-values.
+    */
+   return NULL;
+}
+
+
+ir_rvalue *
+ast_case_label_list::hir(exec_list *instructions,
+                        struct _mesa_glsl_parse_state *state)
+{
+   foreach_list_typed (ast_case_label, label, link, & this->labels)
+      label->hir(instructions, state);
+         
+   /* Case labels do not have r-values.
+    */
+   return NULL;
+}
+
+
+ir_rvalue *
+ast_case_label::hir(exec_list *instructions,
+                   struct _mesa_glsl_parse_state *state)
+{
+   void *ctx = state;
+
+   ir_dereference_variable *deref_fallthru_var =
+      new(ctx) ir_dereference_variable(state->is_fallthru_var);
+   
+   ir_rvalue *const true_val = new(ctx) ir_constant(true);
+
+   /* If not default case, ...
+    */
+   if (this->test_value != NULL) {
+      /* Conditionally set fallthru state based on
+       * comparison of cached test expression value to case label.
+       */
+      ir_rvalue *const test_val = this->test_value->hir(instructions, state);
+
+      ir_dereference_variable *deref_test_var =
+        new(ctx) ir_dereference_variable(state->test_var);
+
+      ir_rvalue *const test_cond = new(ctx) ir_expression(ir_binop_all_equal,
+                                                         glsl_type::bool_type,
+                                                         test_val,
+                                                         deref_test_var);
+
+      ir_assignment *set_fallthru_on_test =
+        new(ctx) ir_assignment(deref_fallthru_var,
+                               true_val,
+                               test_cond);
+   
+      instructions->push_tail(set_fallthru_on_test);
+   } else { /* default case */
+      /* Set falltrhu state.
+       */
+      ir_assignment *set_fallthru =
+        new(ctx) ir_assignment(deref_fallthru_var,
+                               true_val,
+                               NULL);
+   
+      instructions->push_tail(set_fallthru);
+   }
+   
+   /* Case statements do not have r-values.
+    */
+   return NULL;
+}
+
+
 void
 ast_iteration_statement::condition_to_hir(ir_loop *stmt,
                                          struct _mesa_glsl_parse_state *state)
@@ -3373,13 +3792,17 @@ ast_iteration_statement::hir(exec_list *instructions,
    ir_loop *const stmt = new(ctx) ir_loop();
    instructions->push_tail(stmt);
 
-   /* Track the current loop and / or switch-statement nesting.
+   /* Track the current loop nesting.
     */
-   ir_instruction *const nesting = state->loop_or_switch_nesting;
-   ast_iteration_statement *nesting_ast = state->loop_or_switch_nesting_ast;
+   ast_iteration_statement *nesting_ast = state->loop_nesting_ast;
+
+   state->loop_nesting_ast = this;
 
-   state->loop_or_switch_nesting = stmt;
-   state->loop_or_switch_nesting_ast = this;
+   /* Likewise, indicate that following code is closest to a loop,
+    * NOT closest to a switch.
+    */
+   bool saved_is_switch_innermost = state->is_switch_innermost;
+   state->is_switch_innermost = false;
 
    if (mode != ast_do_while)
       condition_to_hir(stmt, state);
@@ -3398,8 +3821,8 @@ ast_iteration_statement::hir(exec_list *instructions,
 
    /* Restore previous nesting before returning.
     */
-   state->loop_or_switch_nesting = nesting;
-   state->loop_or_switch_nesting_ast = nesting_ast;
+   state->loop_nesting_ast = nesting_ast;
+   state->is_switch_innermost = saved_is_switch_innermost;
 
    /* Loops do not have r-values.
     */