Merge remote-tracking branch 'origin/released'

Conflicts:
	mesalib/docs/GL3.txt
	mesalib/src/glsl/linker.cpp
	mesalib/src/mesa/main/depthstencil.c
	mesalib/src/mesa/main/fbobject.c
	mesalib/src/mesa/main/formats.c
	mesalib/src/mesa/main/formats.h
	mesalib/src/mesa/main/framebuffer.c
	mesalib/src/mesa/main/mtypes.h
	mesalib/src/mesa/main/pack.c
	mesalib/src/mesa/main/readpix.c
	mesalib/src/mesa/main/renderbuffer.c
	mesalib/src/mesa/main/samplerobj.c
	mesalib/src/mesa/main/shaderapi.c
	mesalib/src/mesa/main/texenv.c
	mesalib/src/mesa/main/texobj.c
	mesalib/src/mesa/main/uniforms.c
	mesalib/src/mesa/state_tracker/st_cb_clear.c
	mesalib/src/mesa/state_tracker/st_cb_drawpixels.c
	mesalib/src/mesa/state_tracker/st_cb_readpixels.c
	mesalib/src/mesa/state_tracker/st_extensions.c
	mesalib/src/mesa/state_tracker/st_format.c
	mesalib/src/mesa/swrast/s_readpix.c

1 files changed, 1007 insertions, 1005 deletions

diff --git a/mesalib/src/glsl/ir_reader.cpp b/mesalib/src/glsl/ir_reader.cpp
index 201e436be..f3a621734 100644
--- a/mesalib/src/glsl/ir_reader.cpp
+++ b/mesalib/src/glsl/ir_reader.cpp
@@ -1,1005 +1,1007 @@
-/*

- * Copyright © 2010 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.

- */

-

-#include "ir_reader.h"

-#include "glsl_parser_extras.h"

-#include "glsl_types.h"

-#include "s_expression.h"

-

-const static bool debug = false;

-

-class ir_reader {

-public:

-   ir_reader(_mesa_glsl_parse_state *);

-

-   void read(exec_list *instructions, const char *src, bool scan_for_protos);

-

-private:

-   void *mem_ctx;

-   _mesa_glsl_parse_state *state;

-

-   void ir_read_error(s_expression *, const char *fmt, ...);

-

-   const glsl_type *read_type(s_expression *);

-

-   void scan_for_prototypes(exec_list *, s_expression *);

-   ir_function *read_function(s_expression *, bool skip_body);

-   void read_function_sig(ir_function *, s_expression *, bool skip_body);

-

-   void read_instructions(exec_list *, s_expression *, ir_loop *);

-   ir_instruction *read_instruction(s_expression *, ir_loop *);

-   ir_variable *read_declaration(s_expression *);

-   ir_if *read_if(s_expression *, ir_loop *);

-   ir_loop *read_loop(s_expression *);

-   ir_return *read_return(s_expression *);

-   ir_rvalue *read_rvalue(s_expression *);

-   ir_assignment *read_assignment(s_expression *);

-   ir_expression *read_expression(s_expression *);

-   ir_call *read_call(s_expression *);

-   ir_swizzle *read_swizzle(s_expression *);

-   ir_constant *read_constant(s_expression *);

-   ir_texture *read_texture(s_expression *);

-

-   ir_dereference *read_dereference(s_expression *);

-};

-

-ir_reader::ir_reader(_mesa_glsl_parse_state *state) : state(state)

-{

-   this->mem_ctx = state;

-}

-

-void

-_mesa_glsl_read_ir(_mesa_glsl_parse_state *state, exec_list *instructions,

-		   const char *src, bool scan_for_protos)

-{

-   ir_reader r(state);

-   r.read(instructions, src, scan_for_protos);

-}

-

-void

-ir_reader::read(exec_list *instructions, const char *src, bool scan_for_protos)

-{

-   s_expression *expr = s_expression::read_expression(mem_ctx, src);

-   if (expr == NULL) {

-      ir_read_error(NULL, "couldn't parse S-Expression.");

-      return;

-   }

-   

-   if (scan_for_protos) {

-      scan_for_prototypes(instructions, expr);

-      if (state->error)

-	 return;

-   }

-

-   read_instructions(instructions, expr, NULL);

-   ralloc_free(expr);

-

-   if (debug)

-      validate_ir_tree(instructions);

-}

-

-void

-ir_reader::ir_read_error(s_expression *expr, const char *fmt, ...)

-{

-   va_list ap;

-

-   state->error = true;

-

-   if (state->current_function != NULL)

-      ralloc_asprintf_append(&state->info_log, "In function %s:\n",

-			     state->current_function->function_name());

-   ralloc_strcat(&state->info_log, "error: ");

-

-   va_start(ap, fmt);

-   ralloc_vasprintf_append(&state->info_log, fmt, ap);

-   va_end(ap);

-   ralloc_strcat(&state->info_log, "\n");

-

-   if (expr != NULL) {

-      ralloc_strcat(&state->info_log, "...in this context:\n   ");

-      expr->print();

-      ralloc_strcat(&state->info_log, "\n\n");

-   }

-}

-

-const glsl_type *

-ir_reader::read_type(s_expression *expr)

-{

-   s_expression *s_base_type;

-   s_int *s_size;

-

-   s_pattern pat[] = { "array", s_base_type, s_size };

-   if (MATCH(expr, pat)) {

-      const glsl_type *base_type = read_type(s_base_type);

-      if (base_type == NULL) {

-	 ir_read_error(NULL, "when reading base type of array type");

-	 return NULL;

-      }

-

-      return glsl_type::get_array_instance(base_type, s_size->value());

-   }

-   

-   s_symbol *type_sym = SX_AS_SYMBOL(expr);

-   if (type_sym == NULL) {

-      ir_read_error(expr, "expected <type>");

-      return NULL;

-   }

-

-   const glsl_type *type = state->symbols->get_type(type_sym->value());

-   if (type == NULL)

-      ir_read_error(expr, "invalid type: %s", type_sym->value());

-

-   return type;

-}

-

-

-void

-ir_reader::scan_for_prototypes(exec_list *instructions, s_expression *expr)

-{

-   s_list *list = SX_AS_LIST(expr);

-   if (list == NULL) {

-      ir_read_error(expr, "Expected (<instruction> ...); found an atom.");

-      return;

-   }

-

-   foreach_iter(exec_list_iterator, it, list->subexpressions) {

-      s_list *sub = SX_AS_LIST(it.get());

-      if (sub == NULL)

-	 continue; // not a (function ...); ignore it.

-

-      s_symbol *tag = SX_AS_SYMBOL(sub->subexpressions.get_head());

-      if (tag == NULL || strcmp(tag->value(), "function") != 0)

-	 continue; // not a (function ...); ignore it.

-

-      ir_function *f = read_function(sub, true);

-      if (f == NULL)

-	 return;

-      instructions->push_tail(f);

-   }

-}

-

-ir_function *

-ir_reader::read_function(s_expression *expr, bool skip_body)

-{

-   bool added = false;

-   s_symbol *name;

-

-   s_pattern pat[] = { "function", name };

-   if (!PARTIAL_MATCH(expr, pat)) {

-      ir_read_error(expr, "Expected (function <name> (signature ...) ...)");

-      return NULL;

-   }

-

-   ir_function *f = state->symbols->get_function(name->value());

-   if (f == NULL) {

-      f = new(mem_ctx) ir_function(name->value());

-      added = state->symbols->add_function(f);

-      assert(added);

-   }

-

-   exec_list_iterator it = ((s_list *) expr)->subexpressions.iterator();

-   it.next(); // skip "function" tag

-   it.next(); // skip function name

-   for (/* nothing */; it.has_next(); it.next()) {

-      s_expression *s_sig = (s_expression *) it.get();

-      read_function_sig(f, s_sig, skip_body);

-   }

-   return added ? f : NULL;

-}

-

-void

-ir_reader::read_function_sig(ir_function *f, s_expression *expr, bool skip_body)

-{

-   s_expression *type_expr;

-   s_list *paramlist;

-   s_list *body_list;

-

-   s_pattern pat[] = { "signature", type_expr, paramlist, body_list };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "Expected (signature <type> (parameters ...) "

-			  "(<instruction> ...))");

-      return;

-   }

-

-   const glsl_type *return_type = read_type(type_expr);

-   if (return_type == NULL)

-      return;

-

-   s_symbol *paramtag = SX_AS_SYMBOL(paramlist->subexpressions.get_head());

-   if (paramtag == NULL || strcmp(paramtag->value(), "parameters") != 0) {

-      ir_read_error(paramlist, "Expected (parameters ...)");

-      return;

-   }

-

-   // Read the parameters list into a temporary place.

-   exec_list hir_parameters;

-   state->symbols->push_scope();

-

-   exec_list_iterator it = paramlist->subexpressions.iterator();

-   for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {

-      ir_variable *var = read_declaration((s_expression *) it.get());

-      if (var == NULL)

-	 return;

-

-      hir_parameters.push_tail(var);

-   }

-

-   ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);

-   if (sig == NULL && skip_body) {

-      /* If scanning for prototypes, generate a new signature. */

-      sig = new(mem_ctx) ir_function_signature(return_type);

-      sig->is_builtin = true;

-      f->add_signature(sig);

-   } else if (sig != NULL) {

-      const char *badvar = sig->qualifiers_match(&hir_parameters);

-      if (badvar != NULL) {

-	 ir_read_error(expr, "function `%s' parameter `%s' qualifiers "

-		       "don't match prototype", f->name, badvar);

-	 return;

-      }

-

-      if (sig->return_type != return_type) {

-	 ir_read_error(expr, "function `%s' return type doesn't "

-		       "match prototype", f->name);

-	 return;

-      }

-   } else {

-      /* No prototype for this body exists - skip it. */

-      state->symbols->pop_scope();

-      return;

-   }

-   assert(sig != NULL);

-

-   sig->replace_parameters(&hir_parameters);

-

-   if (!skip_body && !body_list->subexpressions.is_empty()) {

-      if (sig->is_defined) {

-	 ir_read_error(expr, "function %s redefined", f->name);

-	 return;

-      }

-      state->current_function = sig;

-      read_instructions(&sig->body, body_list, NULL);

-      state->current_function = NULL;

-      sig->is_defined = true;

-   }

-

-   state->symbols->pop_scope();

-}

-

-void

-ir_reader::read_instructions(exec_list *instructions, s_expression *expr,

-			     ir_loop *loop_ctx)

-{

-   // Read in a list of instructions

-   s_list *list = SX_AS_LIST(expr);

-   if (list == NULL) {

-      ir_read_error(expr, "Expected (<instruction> ...); found an atom.");

-      return;

-   }

-

-   foreach_iter(exec_list_iterator, it, list->subexpressions) {

-      s_expression *sub = (s_expression*) it.get();

-      ir_instruction *ir = read_instruction(sub, loop_ctx);

-      if (ir != NULL) {

-	 /* Global variable declarations should be moved to the top, before

-	  * any functions that might use them.  Functions are added to the

-	  * instruction stream when scanning for prototypes, so without this

-	  * hack, they always appear before variable declarations.

-	  */

-	 if (state->current_function == NULL && ir->as_variable() != NULL)

-	    instructions->push_head(ir);

-	 else

-	    instructions->push_tail(ir);

-      }

-   }

-}

-

-

-ir_instruction *

-ir_reader::read_instruction(s_expression *expr, ir_loop *loop_ctx)

-{

-   s_symbol *symbol = SX_AS_SYMBOL(expr);

-   if (symbol != NULL) {

-      if (strcmp(symbol->value(), "break") == 0 && loop_ctx != NULL)

-	 return new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_break);

-      if (strcmp(symbol->value(), "continue") == 0 && loop_ctx != NULL)

-	 return new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_continue);

-   }

-

-   s_list *list = SX_AS_LIST(expr);

-   if (list == NULL || list->subexpressions.is_empty()) {

-      ir_read_error(expr, "Invalid instruction.\n");

-      return NULL;

-   }

-

-   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());

-   if (tag == NULL) {

-      ir_read_error(expr, "expected instruction tag");

-      return NULL;

-   }

-

-   ir_instruction *inst = NULL;

-   if (strcmp(tag->value(), "declare") == 0) {

-      inst = read_declaration(list);

-   } else if (strcmp(tag->value(), "assign") == 0) {

-      inst = read_assignment(list);

-   } else if (strcmp(tag->value(), "if") == 0) {

-      inst = read_if(list, loop_ctx);

-   } else if (strcmp(tag->value(), "loop") == 0) {

-      inst = read_loop(list);

-   } else if (strcmp(tag->value(), "return") == 0) {

-      inst = read_return(list);

-   } else if (strcmp(tag->value(), "function") == 0) {

-      inst = read_function(list, false);

-   } else {

-      inst = read_rvalue(list);

-      if (inst == NULL)

-	 ir_read_error(NULL, "when reading instruction");

-   }

-   return inst;

-}

-

-ir_variable *

-ir_reader::read_declaration(s_expression *expr)

-{

-   s_list *s_quals;

-   s_expression *s_type;

-   s_symbol *s_name;

-

-   s_pattern pat[] = { "declare", s_quals, s_type, s_name };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (declare (<qualifiers>) <type> <name>)");

-      return NULL;

-   }

-

-   const glsl_type *type = read_type(s_type);

-   if (type == NULL)

-      return NULL;

-

-   ir_variable *var = new(mem_ctx) ir_variable(type, s_name->value(),

-					       ir_var_auto);

-

-   foreach_iter(exec_list_iterator, it, s_quals->subexpressions) {

-      s_symbol *qualifier = SX_AS_SYMBOL(it.get());

-      if (qualifier == NULL) {

-	 ir_read_error(expr, "qualifier list must contain only symbols");

-	 return NULL;

-      }

-

-      // FINISHME: Check for duplicate/conflicting qualifiers.

-      if (strcmp(qualifier->value(), "centroid") == 0) {

-	 var->centroid = 1;

-      } else if (strcmp(qualifier->value(), "invariant") == 0) {

-	 var->invariant = 1;

-      } else if (strcmp(qualifier->value(), "uniform") == 0) {

-	 var->mode = ir_var_uniform;

-      } else if (strcmp(qualifier->value(), "auto") == 0) {

-	 var->mode = ir_var_auto;

-      } else if (strcmp(qualifier->value(), "in") == 0) {

-	 var->mode = ir_var_in;

-      } else if (strcmp(qualifier->value(), "const_in") == 0) {

-	 var->mode = ir_var_const_in;

-      } else if (strcmp(qualifier->value(), "out") == 0) {

-	 var->mode = ir_var_out;

-      } else if (strcmp(qualifier->value(), "inout") == 0) {

-	 var->mode = ir_var_inout;

-      } else if (strcmp(qualifier->value(), "smooth") == 0) {

-	 var->interpolation = ir_var_smooth;

-      } else if (strcmp(qualifier->value(), "flat") == 0) {

-	 var->interpolation = ir_var_flat;

-      } else if (strcmp(qualifier->value(), "noperspective") == 0) {

-	 var->interpolation = ir_var_noperspective;

-      } else {

-	 ir_read_error(expr, "unknown qualifier: %s", qualifier->value());

-	 return NULL;

-      }

-   }

-

-   // Add the variable to the symbol table

-   state->symbols->add_variable(var);

-

-   return var;

-}

-

-

-ir_if *

-ir_reader::read_if(s_expression *expr, ir_loop *loop_ctx)

-{

-   s_expression *s_cond;

-   s_expression *s_then;

-   s_expression *s_else;

-

-   s_pattern pat[] = { "if", s_cond, s_then, s_else };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (if <condition> (<then>...) (<else>...))");

-      return NULL;

-   }

-

-   ir_rvalue *condition = read_rvalue(s_cond);

-   if (condition == NULL) {

-      ir_read_error(NULL, "when reading condition of (if ...)");

-      return NULL;

-   }

-

-   ir_if *iff = new(mem_ctx) ir_if(condition);

-

-   read_instructions(&iff->then_instructions, s_then, loop_ctx);

-   read_instructions(&iff->else_instructions, s_else, loop_ctx);

-   if (state->error) {

-      delete iff;

-      iff = NULL;

-   }

-   return iff;

-}

-

-

-ir_loop *

-ir_reader::read_loop(s_expression *expr)

-{

-   s_expression *s_counter, *s_from, *s_to, *s_inc, *s_body;

-

-   s_pattern pat[] = { "loop", s_counter, s_from, s_to, s_inc, s_body };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (loop <counter> <from> <to> "

-			  "<increment> <body>)");

-      return NULL;

-   }

-

-   // FINISHME: actually read the count/from/to fields.

-

-   ir_loop *loop = new(mem_ctx) ir_loop;

-   read_instructions(&loop->body_instructions, s_body, loop);

-   if (state->error) {

-      delete loop;

-      loop = NULL;

-   }

-   return loop;

-}

-

-

-ir_return *

-ir_reader::read_return(s_expression *expr)

-{

-   s_expression *s_retval;

-

-   s_pattern pat[] = { "return", s_retval};

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (return <rvalue>)");

-      return NULL;

-   }

-

-   ir_rvalue *retval = read_rvalue(s_retval);

-   if (retval == NULL) {

-      ir_read_error(NULL, "when reading return value");

-      return NULL;

-   }

-

-   return new(mem_ctx) ir_return(retval);

-}

-

-

-ir_rvalue *

-ir_reader::read_rvalue(s_expression *expr)

-{

-   s_list *list = SX_AS_LIST(expr);

-   if (list == NULL || list->subexpressions.is_empty())

-      return NULL;

-

-   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());

-   if (tag == NULL) {

-      ir_read_error(expr, "expected rvalue tag");

-      return NULL;

-   }

-

-   ir_rvalue *rvalue = read_dereference(list);

-   if (rvalue != NULL || state->error)

-      return rvalue;

-   else if (strcmp(tag->value(), "swiz") == 0) {

-      rvalue = read_swizzle(list);

-   } else if (strcmp(tag->value(), "expression") == 0) {

-      rvalue = read_expression(list);

-   } else if (strcmp(tag->value(), "call") == 0) {

-      rvalue = read_call(list);

-   } else if (strcmp(tag->value(), "constant") == 0) {

-      rvalue = read_constant(list);

-   } else {

-      rvalue = read_texture(list);

-      if (rvalue == NULL && !state->error)

-	 ir_read_error(expr, "unrecognized rvalue tag: %s", tag->value());

-   }

-

-   return rvalue;

-}

-

-ir_assignment *

-ir_reader::read_assignment(s_expression *expr)

-{

-   s_expression *cond_expr = NULL;

-   s_expression *lhs_expr, *rhs_expr;

-   s_list       *mask_list;

-

-   s_pattern pat4[] = { "assign",            mask_list, lhs_expr, rhs_expr };

-   s_pattern pat5[] = { "assign", cond_expr, mask_list, lhs_expr, rhs_expr };

-   if (!MATCH(expr, pat4) && !MATCH(expr, pat5)) {

-      ir_read_error(expr, "expected (assign [<condition>] (<write mask>) "

-			  "<lhs> <rhs>)");

-      return NULL;

-   }

-

-   ir_rvalue *condition = NULL;

-   if (cond_expr != NULL) {

-      condition = read_rvalue(cond_expr);

-      if (condition == NULL) {

-	 ir_read_error(NULL, "when reading condition of assignment");

-	 return NULL;

-      }

-   }

-

-   unsigned mask = 0;

-

-   s_symbol *mask_symbol;

-   s_pattern mask_pat[] = { mask_symbol };

-   if (MATCH(mask_list, mask_pat)) {

-      const char *mask_str = mask_symbol->value();

-      unsigned mask_length = strlen(mask_str);

-      if (mask_length > 4) {

-	 ir_read_error(expr, "invalid write mask: %s", mask_str);

-	 return NULL;

-      }

-

-      const unsigned idx_map[] = { 3, 0, 1, 2 }; /* w=bit 3, x=0, y=1, z=2 */

-

-      for (unsigned i = 0; i < mask_length; i++) {

-	 if (mask_str[i] < 'w' || mask_str[i] > 'z') {

-	    ir_read_error(expr, "write mask contains invalid character: %c",

-			  mask_str[i]);

-	    return NULL;

-	 }

-	 mask |= 1 << idx_map[mask_str[i] - 'w'];

-      }

-   } else if (!mask_list->subexpressions.is_empty()) {

-      ir_read_error(mask_list, "expected () or (<write mask>)");

-      return NULL;

-   }

-

-   ir_dereference *lhs = read_dereference(lhs_expr);

-   if (lhs == NULL) {

-      ir_read_error(NULL, "when reading left-hand side of assignment");

-      return NULL;

-   }

-

-   ir_rvalue *rhs = read_rvalue(rhs_expr);

-   if (rhs == NULL) {

-      ir_read_error(NULL, "when reading right-hand side of assignment");

-      return NULL;

-   }

-

-   if (mask == 0 && (lhs->type->is_vector() || lhs->type->is_scalar())) {

-      ir_read_error(expr, "non-zero write mask required.");

-      return NULL;

-   }

-

-   return new(mem_ctx) ir_assignment(lhs, rhs, condition, mask);

-}

-

-ir_call *

-ir_reader::read_call(s_expression *expr)

-{

-   s_symbol *name;

-   s_list *params;

-

-   s_pattern pat[] = { "call", name, params };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (call <name> (<param> ...))");

-      return NULL;

-   }

-

-   exec_list parameters;

-

-   foreach_iter(exec_list_iterator, it, params->subexpressions) {

-      s_expression *expr = (s_expression*) it.get();

-      ir_rvalue *param = read_rvalue(expr);

-      if (param == NULL) {

-	 ir_read_error(expr, "when reading parameter to function call");

-	 return NULL;

-      }

-      parameters.push_tail(param);

-   }

-

-   ir_function *f = state->symbols->get_function(name->value());

-   if (f == NULL) {

-      ir_read_error(expr, "found call to undefined function %s",

-		    name->value());

-      return NULL;

-   }

-

-   ir_function_signature *callee = f->matching_signature(&parameters);

-   if (callee == NULL) {

-      ir_read_error(expr, "couldn't find matching signature for function "

-                    "%s", name->value());

-      return NULL;

-   }

-

-   return new(mem_ctx) ir_call(callee, &parameters);

-}

-

-ir_expression *

-ir_reader::read_expression(s_expression *expr)

-{

-   s_expression *s_type;

-   s_symbol *s_op;

-   s_expression *s_arg1;

-

-   s_pattern pat[] = { "expression", s_type, s_op, s_arg1 };

-   if (!PARTIAL_MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (expression <type> <operator> "

-			  "<operand> [<operand>])");

-      return NULL;

-   }

-   s_expression *s_arg2 = (s_expression *) s_arg1->next; // may be tail sentinel

-

-   const glsl_type *type = read_type(s_type);

-   if (type == NULL)

-      return NULL;

-

-   /* Read the operator */

-   ir_expression_operation op = ir_expression::get_operator(s_op->value());

-   if (op == (ir_expression_operation) -1) {

-      ir_read_error(expr, "invalid operator: %s", s_op->value());

-      return NULL;

-   }

-    

-   unsigned num_operands = ir_expression::get_num_operands(op);

-   if (num_operands == 1 && !s_arg1->next->is_tail_sentinel()) {

-      ir_read_error(expr, "expected (expression <type> %s <operand>)",

-		    s_op->value());

-      return NULL;

-   }

-

-   ir_rvalue *arg1 = read_rvalue(s_arg1);

-   ir_rvalue *arg2 = NULL;

-   if (arg1 == NULL) {

-      ir_read_error(NULL, "when reading first operand of %s", s_op->value());

-      return NULL;

-   }

-

-   if (num_operands == 2) {

-      if (s_arg2->is_tail_sentinel() || !s_arg2->next->is_tail_sentinel()) {

-	 ir_read_error(expr, "expected (expression <type> %s <operand> "

-			     "<operand>)", s_op->value());

-	 return NULL;

-      }

-      arg2 = read_rvalue(s_arg2);

-      if (arg2 == NULL) {

-	 ir_read_error(NULL, "when reading second operand of %s",

-		       s_op->value());

-	 return NULL;

-      }

-   }

-

-   return new(mem_ctx) ir_expression(op, type, arg1, arg2);

-}

-

-ir_swizzle *

-ir_reader::read_swizzle(s_expression *expr)

-{

-   s_symbol *swiz;

-   s_expression *sub;

-

-   s_pattern pat[] = { "swiz", swiz, sub };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (swiz <swizzle> <rvalue>)");

-      return NULL;

-   }

-

-   if (strlen(swiz->value()) > 4) {

-      ir_read_error(expr, "expected a valid swizzle; found %s", swiz->value());

-      return NULL;

-   }

-

-   ir_rvalue *rvalue = read_rvalue(sub);

-   if (rvalue == NULL)

-      return NULL;

-

-   ir_swizzle *ir = ir_swizzle::create(rvalue, swiz->value(),

-				       rvalue->type->vector_elements);

-   if (ir == NULL)

-      ir_read_error(expr, "invalid swizzle");

-

-   return ir;

-}

-

-ir_constant *

-ir_reader::read_constant(s_expression *expr)

-{

-   s_expression *type_expr;

-   s_list *values;

-

-   s_pattern pat[] = { "constant", type_expr, values };

-   if (!MATCH(expr, pat)) {

-      ir_read_error(expr, "expected (constant <type> (...))");

-      return NULL;

-   }

-

-   const glsl_type *type = read_type(type_expr);

-   if (type == NULL)

-      return NULL;

-

-   if (values == NULL) {

-      ir_read_error(expr, "expected (constant <type> (...))");

-      return NULL;

-   }

-

-   if (type->is_array()) {

-      unsigned elements_supplied = 0;

-      exec_list elements;

-      foreach_iter(exec_list_iterator, it, values->subexpressions) {

-	 s_expression *elt = (s_expression *) it.get();

-	 ir_constant *ir_elt = read_constant(elt);

-	 if (ir_elt == NULL)

-	    return NULL;

-	 elements.push_tail(ir_elt);

-	 elements_supplied++;

-      }

-

-      if (elements_supplied != type->length) {

-	 ir_read_error(values, "expected exactly %u array elements, "

-		       "given %u", type->length, elements_supplied);

-	 return NULL;

-      }

-      return new(mem_ctx) ir_constant(type, &elements);

-   }

-

-   const glsl_type *const base_type = type->get_base_type();

-

-   ir_constant_data data = { { 0 } };

-

-   // Read in list of values (at most 16).

-   int k = 0;

-   foreach_iter(exec_list_iterator, it, values->subexpressions) {

-      if (k >= 16) {

-	 ir_read_error(values, "expected at most 16 numbers");

-	 return NULL;

-      }

-

-      s_expression *expr = (s_expression*) it.get();

-

-      if (base_type->base_type == GLSL_TYPE_FLOAT) {

-	 s_number *value = SX_AS_NUMBER(expr);

-	 if (value == NULL) {

-	    ir_read_error(values, "expected numbers");

-	    return NULL;

-	 }

-	 data.f[k] = value->fvalue();

-      } else {

-	 s_int *value = SX_AS_INT(expr);

-	 if (value == NULL) {

-	    ir_read_error(values, "expected integers");

-	    return NULL;

-	 }

-

-	 switch (base_type->base_type) {

-	 case GLSL_TYPE_UINT: {

-	    data.u[k] = value->value();

-	    break;

-	 }

-	 case GLSL_TYPE_INT: {

-	    data.i[k] = value->value();

-	    break;

-	 }

-	 case GLSL_TYPE_BOOL: {

-	    data.b[k] = value->value();

-	    break;

-	 }

-	 default:

-	    ir_read_error(values, "unsupported constant type");

-	    return NULL;

-	 }

-      }

-      ++k;

-   }

-

-   return new(mem_ctx) ir_constant(type, &data);

-}

-

-ir_dereference *

-ir_reader::read_dereference(s_expression *expr)

-{

-   s_symbol *s_var;

-   s_expression *s_subject;

-   s_expression *s_index;

-   s_symbol *s_field;

-

-   s_pattern var_pat[] = { "var_ref", s_var };

-   s_pattern array_pat[] = { "array_ref", s_subject, s_index };

-   s_pattern record_pat[] = { "record_ref", s_subject, s_field };

-

-   if (MATCH(expr, var_pat)) {

-      ir_variable *var = state->symbols->get_variable(s_var->value());

-      if (var == NULL) {

-	 ir_read_error(expr, "undeclared variable: %s", s_var->value());

-	 return NULL;

-      }

-      return new(mem_ctx) ir_dereference_variable(var);

-   } else if (MATCH(expr, array_pat)) {

-      ir_rvalue *subject = read_rvalue(s_subject);

-      if (subject == NULL) {

-	 ir_read_error(NULL, "when reading the subject of an array_ref");

-	 return NULL;

-      }

-

-      ir_rvalue *idx = read_rvalue(s_index);

-      if (subject == NULL) {

-	 ir_read_error(NULL, "when reading the index of an array_ref");

-	 return NULL;

-      }

-      return new(mem_ctx) ir_dereference_array(subject, idx);

-   } else if (MATCH(expr, record_pat)) {

-      ir_rvalue *subject = read_rvalue(s_subject);

-      if (subject == NULL) {

-	 ir_read_error(NULL, "when reading the subject of a record_ref");

-	 return NULL;

-      }

-      return new(mem_ctx) ir_dereference_record(subject, s_field->value());

-   }

-   return NULL;

-}

-

-ir_texture *

-ir_reader::read_texture(s_expression *expr)

-{

-   s_symbol *tag = NULL;

-   s_expression *s_type = NULL;

-   s_expression *s_sampler = NULL;

-   s_expression *s_coord = NULL;

-   s_expression *s_offset = NULL;

-   s_expression *s_proj = NULL;

-   s_list *s_shadow = NULL;

-   s_expression *s_lod = NULL;

-

-   ir_texture_opcode op = ir_tex; /* silence warning */

-

-   s_pattern tex_pattern[] =

-      { "tex", s_type, s_sampler, s_coord, s_offset, s_proj, s_shadow };

-   s_pattern txf_pattern[] =

-      { "txf", s_type, s_sampler, s_coord, s_offset, s_lod };

-   s_pattern other_pattern[] =

-      { tag, s_type, s_sampler, s_coord, s_offset, s_proj, s_shadow, s_lod };

-

-   if (MATCH(expr, tex_pattern)) {

-      op = ir_tex;

-   } else if (MATCH(expr, txf_pattern)) {

-      op = ir_txf;

-   } else if (MATCH(expr, other_pattern)) {

-      op = ir_texture::get_opcode(tag->value());

-      if (op == -1)

-	 return NULL;

-   } else {

-      ir_read_error(NULL, "unexpected texture pattern");

-      return NULL;

-   }

-

-   ir_texture *tex = new(mem_ctx) ir_texture(op);

-

-   // Read return type

-   const glsl_type *type = read_type(s_type);

-   if (type == NULL) {

-      ir_read_error(NULL, "when reading type in (%s ...)",

-		    tex->opcode_string());

-      return NULL;

-   }

-

-   // Read sampler (must be a deref)

-   ir_dereference *sampler = read_dereference(s_sampler);

-   if (sampler == NULL) {

-      ir_read_error(NULL, "when reading sampler in (%s ...)",

-		    tex->opcode_string());

-      return NULL;

-   }

-   tex->set_sampler(sampler, type);

-

-   // Read coordinate (any rvalue)

-   tex->coordinate = read_rvalue(s_coord);

-   if (tex->coordinate == NULL) {

-      ir_read_error(NULL, "when reading coordinate in (%s ...)",

-		    tex->opcode_string());

-      return NULL;

-   }

-

-   // Read texel offset - either 0 or an rvalue.

-   s_int *si_offset = SX_AS_INT(s_offset);

-   if (si_offset == NULL || si_offset->value() != 0) {

-      tex->offset = read_rvalue(s_offset);

-      if (tex->offset == NULL) {

-	 ir_read_error(s_offset, "expected 0 or an expression");

-	 return NULL;

-      }

-   }

-

-   if (op != ir_txf) {

-      s_int *proj_as_int = SX_AS_INT(s_proj);

-      if (proj_as_int && proj_as_int->value() == 1) {

-	 tex->projector = NULL;

-      } else {

-	 tex->projector = read_rvalue(s_proj);

-	 if (tex->projector == NULL) {

-	    ir_read_error(NULL, "when reading projective divide in (%s ..)",

-	                  tex->opcode_string());

-	    return NULL;

-	 }

-      }

-

-      if (s_shadow->subexpressions.is_empty()) {

-	 tex->shadow_comparitor = NULL;

-      } else {

-	 tex->shadow_comparitor = read_rvalue(s_shadow);

-	 if (tex->shadow_comparitor == NULL) {

-	    ir_read_error(NULL, "when reading shadow comparitor in (%s ..)",

-			  tex->opcode_string());

-	    return NULL;

-	 }

-      }

-   }

-

-   switch (op) {

-   case ir_txb:

-      tex->lod_info.bias = read_rvalue(s_lod);

-      if (tex->lod_info.bias == NULL) {

-	 ir_read_error(NULL, "when reading LOD bias in (txb ...)");

-	 return NULL;

-      }

-      break;

-   case ir_txl:

-   case ir_txf:

-      tex->lod_info.lod = read_rvalue(s_lod);

-      if (tex->lod_info.lod == NULL) {

-	 ir_read_error(NULL, "when reading LOD in (%s ...)",

-		       tex->opcode_string());

-	 return NULL;

-      }

-      break;

-   case ir_txd: {

-      s_expression *s_dx, *s_dy;

-      s_pattern dxdy_pat[] = { s_dx, s_dy };

-      if (!MATCH(s_lod, dxdy_pat)) {

-	 ir_read_error(s_lod, "expected (dPdx dPdy) in (txd ...)");

-	 return NULL;

-      }

-      tex->lod_info.grad.dPdx = read_rvalue(s_dx);

-      if (tex->lod_info.grad.dPdx == NULL) {

-	 ir_read_error(NULL, "when reading dPdx in (txd ...)");

-	 return NULL;

-      }

-      tex->lod_info.grad.dPdy = read_rvalue(s_dy);

-      if (tex->lod_info.grad.dPdy == NULL) {

-	 ir_read_error(NULL, "when reading dPdy in (txd ...)");

-	 return NULL;

-      }

-      break;

-   }

-   default:

-      // tex doesn't have any extra parameters.

-      break;

-   };

-   return tex;

-}

+/*
+ * Copyright © 2010 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.
+ */
+
+#include "ir_reader.h"
+#include "glsl_parser_extras.h"
+#include "glsl_types.h"
+#include "s_expression.h"
+
+const static bool debug = false;
+
+class ir_reader {
+public:
+   ir_reader(_mesa_glsl_parse_state *);
+
+   void read(exec_list *instructions, const char *src, bool scan_for_protos);
+
+private:
+   void *mem_ctx;
+   _mesa_glsl_parse_state *state;
+
+   void ir_read_error(s_expression *, const char *fmt, ...);
+
+   const glsl_type *read_type(s_expression *);
+
+   void scan_for_prototypes(exec_list *, s_expression *);
+   ir_function *read_function(s_expression *, bool skip_body);
+   void read_function_sig(ir_function *, s_expression *, bool skip_body);
+
+   void read_instructions(exec_list *, s_expression *, ir_loop *);
+   ir_instruction *read_instruction(s_expression *, ir_loop *);
+   ir_variable *read_declaration(s_expression *);
+   ir_if *read_if(s_expression *, ir_loop *);
+   ir_loop *read_loop(s_expression *);
+   ir_return *read_return(s_expression *);
+   ir_rvalue *read_rvalue(s_expression *);
+   ir_assignment *read_assignment(s_expression *);
+   ir_expression *read_expression(s_expression *);
+   ir_call *read_call(s_expression *);
+   ir_swizzle *read_swizzle(s_expression *);
+   ir_constant *read_constant(s_expression *);
+   ir_texture *read_texture(s_expression *);
+
+   ir_dereference *read_dereference(s_expression *);
+};
+
+ir_reader::ir_reader(_mesa_glsl_parse_state *state) : state(state)
+{
+   this->mem_ctx = state;
+}
+
+void
+_mesa_glsl_read_ir(_mesa_glsl_parse_state *state, exec_list *instructions,
+		   const char *src, bool scan_for_protos)
+{
+   ir_reader r(state);
+   r.read(instructions, src, scan_for_protos);
+}
+
+void
+ir_reader::read(exec_list *instructions, const char *src, bool scan_for_protos)
+{
+   s_expression *expr = s_expression::read_expression(mem_ctx, src);
+   if (expr == NULL) {
+      ir_read_error(NULL, "couldn't parse S-Expression.");
+      return;
+   }
+   
+   if (scan_for_protos) {
+      scan_for_prototypes(instructions, expr);
+      if (state->error)
+	 return;
+   }
+
+   read_instructions(instructions, expr, NULL);
+   ralloc_free(expr);
+
+   if (debug)
+      validate_ir_tree(instructions);
+}
+
+void
+ir_reader::ir_read_error(s_expression *expr, const char *fmt, ...)
+{
+   va_list ap;
+
+   state->error = true;
+
+   if (state->current_function != NULL)
+      ralloc_asprintf_append(&state->info_log, "In function %s:\n",
+			     state->current_function->function_name());
+   ralloc_strcat(&state->info_log, "error: ");
+
+   va_start(ap, fmt);
+   ralloc_vasprintf_append(&state->info_log, fmt, ap);
+   va_end(ap);
+   ralloc_strcat(&state->info_log, "\n");
+
+   if (expr != NULL) {
+      ralloc_strcat(&state->info_log, "...in this context:\n   ");
+      expr->print();
+      ralloc_strcat(&state->info_log, "\n\n");
+   }
+}
+
+const glsl_type *
+ir_reader::read_type(s_expression *expr)
+{
+   s_expression *s_base_type;
+   s_int *s_size;
+
+   s_pattern pat[] = { "array", s_base_type, s_size };
+   if (MATCH(expr, pat)) {
+      const glsl_type *base_type = read_type(s_base_type);
+      if (base_type == NULL) {
+	 ir_read_error(NULL, "when reading base type of array type");
+	 return NULL;
+      }
+
+      return glsl_type::get_array_instance(base_type, s_size->value());
+   }
+   
+   s_symbol *type_sym = SX_AS_SYMBOL(expr);
+   if (type_sym == NULL) {
+      ir_read_error(expr, "expected <type>");
+      return NULL;
+   }
+
+   const glsl_type *type = state->symbols->get_type(type_sym->value());
+   if (type == NULL)
+      ir_read_error(expr, "invalid type: %s", type_sym->value());
+
+   return type;
+}
+
+
+void
+ir_reader::scan_for_prototypes(exec_list *instructions, s_expression *expr)
+{
+   s_list *list = SX_AS_LIST(expr);
+   if (list == NULL) {
+      ir_read_error(expr, "Expected (<instruction> ...); found an atom.");
+      return;
+   }
+
+   foreach_iter(exec_list_iterator, it, list->subexpressions) {
+      s_list *sub = SX_AS_LIST(it.get());
+      if (sub == NULL)
+	 continue; // not a (function ...); ignore it.
+
+      s_symbol *tag = SX_AS_SYMBOL(sub->subexpressions.get_head());
+      if (tag == NULL || strcmp(tag->value(), "function") != 0)
+	 continue; // not a (function ...); ignore it.
+
+      ir_function *f = read_function(sub, true);
+      if (f == NULL)
+	 return;
+      instructions->push_tail(f);
+   }
+}
+
+ir_function *
+ir_reader::read_function(s_expression *expr, bool skip_body)
+{
+   bool added = false;
+   s_symbol *name;
+
+   s_pattern pat[] = { "function", name };
+   if (!PARTIAL_MATCH(expr, pat)) {
+      ir_read_error(expr, "Expected (function <name> (signature ...) ...)");
+      return NULL;
+   }
+
+   ir_function *f = state->symbols->get_function(name->value());
+   if (f == NULL) {
+      f = new(mem_ctx) ir_function(name->value());
+      added = state->symbols->add_function(f);
+      assert(added);
+   }
+
+   exec_list_iterator it = ((s_list *) expr)->subexpressions.iterator();
+   it.next(); // skip "function" tag
+   it.next(); // skip function name
+   for (/* nothing */; it.has_next(); it.next()) {
+      s_expression *s_sig = (s_expression *) it.get();
+      read_function_sig(f, s_sig, skip_body);
+   }
+   return added ? f : NULL;
+}
+
+void
+ir_reader::read_function_sig(ir_function *f, s_expression *expr, bool skip_body)
+{
+   s_expression *type_expr;
+   s_list *paramlist;
+   s_list *body_list;
+
+   s_pattern pat[] = { "signature", type_expr, paramlist, body_list };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "Expected (signature <type> (parameters ...) "
+			  "(<instruction> ...))");
+      return;
+   }
+
+   const glsl_type *return_type = read_type(type_expr);
+   if (return_type == NULL)
+      return;
+
+   s_symbol *paramtag = SX_AS_SYMBOL(paramlist->subexpressions.get_head());
+   if (paramtag == NULL || strcmp(paramtag->value(), "parameters") != 0) {
+      ir_read_error(paramlist, "Expected (parameters ...)");
+      return;
+   }
+
+   // Read the parameters list into a temporary place.
+   exec_list hir_parameters;
+   state->symbols->push_scope();
+
+   exec_list_iterator it = paramlist->subexpressions.iterator();
+   for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {
+      ir_variable *var = read_declaration((s_expression *) it.get());
+      if (var == NULL)
+	 return;
+
+      hir_parameters.push_tail(var);
+   }
+
+   ir_function_signature *sig = f->exact_matching_signature(&hir_parameters);
+   if (sig == NULL && skip_body) {
+      /* If scanning for prototypes, generate a new signature. */
+      sig = new(mem_ctx) ir_function_signature(return_type);
+      sig->is_builtin = true;
+      f->add_signature(sig);
+   } else if (sig != NULL) {
+      const char *badvar = sig->qualifiers_match(&hir_parameters);
+      if (badvar != NULL) {
+	 ir_read_error(expr, "function `%s' parameter `%s' qualifiers "
+		       "don't match prototype", f->name, badvar);
+	 return;
+      }
+
+      if (sig->return_type != return_type) {
+	 ir_read_error(expr, "function `%s' return type doesn't "
+		       "match prototype", f->name);
+	 return;
+      }
+   } else {
+      /* No prototype for this body exists - skip it. */
+      state->symbols->pop_scope();
+      return;
+   }
+   assert(sig != NULL);
+
+   sig->replace_parameters(&hir_parameters);
+
+   if (!skip_body && !body_list->subexpressions.is_empty()) {
+      if (sig->is_defined) {
+	 ir_read_error(expr, "function %s redefined", f->name);
+	 return;
+      }
+      state->current_function = sig;
+      read_instructions(&sig->body, body_list, NULL);
+      state->current_function = NULL;
+      sig->is_defined = true;
+   }
+
+   state->symbols->pop_scope();
+}
+
+void
+ir_reader::read_instructions(exec_list *instructions, s_expression *expr,
+			     ir_loop *loop_ctx)
+{
+   // Read in a list of instructions
+   s_list *list = SX_AS_LIST(expr);
+   if (list == NULL) {
+      ir_read_error(expr, "Expected (<instruction> ...); found an atom.");
+      return;
+   }
+
+   foreach_iter(exec_list_iterator, it, list->subexpressions) {
+      s_expression *sub = (s_expression*) it.get();
+      ir_instruction *ir = read_instruction(sub, loop_ctx);
+      if (ir != NULL) {
+	 /* Global variable declarations should be moved to the top, before
+	  * any functions that might use them.  Functions are added to the
+	  * instruction stream when scanning for prototypes, so without this
+	  * hack, they always appear before variable declarations.
+	  */
+	 if (state->current_function == NULL && ir->as_variable() != NULL)
+	    instructions->push_head(ir);
+	 else
+	    instructions->push_tail(ir);
+      }
+   }
+}
+
+
+ir_instruction *
+ir_reader::read_instruction(s_expression *expr, ir_loop *loop_ctx)
+{
+   s_symbol *symbol = SX_AS_SYMBOL(expr);
+   if (symbol != NULL) {
+      if (strcmp(symbol->value(), "break") == 0 && loop_ctx != NULL)
+	 return new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_break);
+      if (strcmp(symbol->value(), "continue") == 0 && loop_ctx != NULL)
+	 return new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_continue);
+   }
+
+   s_list *list = SX_AS_LIST(expr);
+   if (list == NULL || list->subexpressions.is_empty()) {
+      ir_read_error(expr, "Invalid instruction.\n");
+      return NULL;
+   }
+
+   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
+   if (tag == NULL) {
+      ir_read_error(expr, "expected instruction tag");
+      return NULL;
+   }
+
+   ir_instruction *inst = NULL;
+   if (strcmp(tag->value(), "declare") == 0) {
+      inst = read_declaration(list);
+   } else if (strcmp(tag->value(), "assign") == 0) {
+      inst = read_assignment(list);
+   } else if (strcmp(tag->value(), "if") == 0) {
+      inst = read_if(list, loop_ctx);
+   } else if (strcmp(tag->value(), "loop") == 0) {
+      inst = read_loop(list);
+   } else if (strcmp(tag->value(), "return") == 0) {
+      inst = read_return(list);
+   } else if (strcmp(tag->value(), "function") == 0) {
+      inst = read_function(list, false);
+   } else {
+      inst = read_rvalue(list);
+      if (inst == NULL)
+	 ir_read_error(NULL, "when reading instruction");
+   }
+   return inst;
+}
+
+ir_variable *
+ir_reader::read_declaration(s_expression *expr)
+{
+   s_list *s_quals;
+   s_expression *s_type;
+   s_symbol *s_name;
+
+   s_pattern pat[] = { "declare", s_quals, s_type, s_name };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (declare (<qualifiers>) <type> <name>)");
+      return NULL;
+   }
+
+   const glsl_type *type = read_type(s_type);
+   if (type == NULL)
+      return NULL;
+
+   ir_variable *var = new(mem_ctx) ir_variable(type, s_name->value(),
+					       ir_var_auto);
+
+   foreach_iter(exec_list_iterator, it, s_quals->subexpressions) {
+      s_symbol *qualifier = SX_AS_SYMBOL(it.get());
+      if (qualifier == NULL) {
+	 ir_read_error(expr, "qualifier list must contain only symbols");
+	 return NULL;
+      }
+
+      // FINISHME: Check for duplicate/conflicting qualifiers.
+      if (strcmp(qualifier->value(), "centroid") == 0) {
+	 var->centroid = 1;
+      } else if (strcmp(qualifier->value(), "invariant") == 0) {
+	 var->invariant = 1;
+      } else if (strcmp(qualifier->value(), "uniform") == 0) {
+	 var->mode = ir_var_uniform;
+      } else if (strcmp(qualifier->value(), "auto") == 0) {
+	 var->mode = ir_var_auto;
+      } else if (strcmp(qualifier->value(), "in") == 0) {
+	 var->mode = ir_var_in;
+      } else if (strcmp(qualifier->value(), "const_in") == 0) {
+	 var->mode = ir_var_const_in;
+      } else if (strcmp(qualifier->value(), "out") == 0) {
+	 var->mode = ir_var_out;
+      } else if (strcmp(qualifier->value(), "inout") == 0) {
+	 var->mode = ir_var_inout;
+      } else if (strcmp(qualifier->value(), "smooth") == 0) {
+	 var->interpolation = ir_var_smooth;
+      } else if (strcmp(qualifier->value(), "flat") == 0) {
+	 var->interpolation = ir_var_flat;
+      } else if (strcmp(qualifier->value(), "noperspective") == 0) {
+	 var->interpolation = ir_var_noperspective;
+      } else {
+	 ir_read_error(expr, "unknown qualifier: %s", qualifier->value());
+	 return NULL;
+      }
+   }
+
+   // Add the variable to the symbol table
+   state->symbols->add_variable(var);
+
+   return var;
+}
+
+
+ir_if *
+ir_reader::read_if(s_expression *expr, ir_loop *loop_ctx)
+{
+   s_expression *s_cond;
+   s_expression *s_then;
+   s_expression *s_else;
+
+   s_pattern pat[] = { "if", s_cond, s_then, s_else };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (if <condition> (<then>...) (<else>...))");
+      return NULL;
+   }
+
+   ir_rvalue *condition = read_rvalue(s_cond);
+   if (condition == NULL) {
+      ir_read_error(NULL, "when reading condition of (if ...)");
+      return NULL;
+   }
+
+   ir_if *iff = new(mem_ctx) ir_if(condition);
+
+   read_instructions(&iff->then_instructions, s_then, loop_ctx);
+   read_instructions(&iff->else_instructions, s_else, loop_ctx);
+   if (state->error) {
+      delete iff;
+      iff = NULL;
+   }
+   return iff;
+}
+
+
+ir_loop *
+ir_reader::read_loop(s_expression *expr)
+{
+   s_expression *s_counter, *s_from, *s_to, *s_inc, *s_body;
+
+   s_pattern pat[] = { "loop", s_counter, s_from, s_to, s_inc, s_body };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (loop <counter> <from> <to> "
+			  "<increment> <body>)");
+      return NULL;
+   }
+
+   // FINISHME: actually read the count/from/to fields.
+
+   ir_loop *loop = new(mem_ctx) ir_loop;
+   read_instructions(&loop->body_instructions, s_body, loop);
+   if (state->error) {
+      delete loop;
+      loop = NULL;
+   }
+   return loop;
+}
+
+
+ir_return *
+ir_reader::read_return(s_expression *expr)
+{
+   s_expression *s_retval;
+
+   s_pattern return_value_pat[] = { "return", s_retval};
+   s_pattern return_void_pat[] = { "return" };
+   if (MATCH(expr, return_value_pat)) {
+      ir_rvalue *retval = read_rvalue(s_retval);
+      if (retval == NULL) {
+         ir_read_error(NULL, "when reading return value");
+         return NULL;
+      }
+      return new(mem_ctx) ir_return(retval);
+   } else if (MATCH(expr, return_void_pat)) {
+      return new(mem_ctx) ir_return;
+   } else {
+      ir_read_error(expr, "expected (return <rvalue>) or (return)");
+      return NULL;
+   }
+}
+
+
+ir_rvalue *
+ir_reader::read_rvalue(s_expression *expr)
+{
+   s_list *list = SX_AS_LIST(expr);
+   if (list == NULL || list->subexpressions.is_empty())
+      return NULL;
+
+   s_symbol *tag = SX_AS_SYMBOL(list->subexpressions.get_head());
+   if (tag == NULL) {
+      ir_read_error(expr, "expected rvalue tag");
+      return NULL;
+   }
+
+   ir_rvalue *rvalue = read_dereference(list);
+   if (rvalue != NULL || state->error)
+      return rvalue;
+   else if (strcmp(tag->value(), "swiz") == 0) {
+      rvalue = read_swizzle(list);
+   } else if (strcmp(tag->value(), "expression") == 0) {
+      rvalue = read_expression(list);
+   } else if (strcmp(tag->value(), "call") == 0) {
+      rvalue = read_call(list);
+   } else if (strcmp(tag->value(), "constant") == 0) {
+      rvalue = read_constant(list);
+   } else {
+      rvalue = read_texture(list);
+      if (rvalue == NULL && !state->error)
+	 ir_read_error(expr, "unrecognized rvalue tag: %s", tag->value());
+   }
+
+   return rvalue;
+}
+
+ir_assignment *
+ir_reader::read_assignment(s_expression *expr)
+{
+   s_expression *cond_expr = NULL;
+   s_expression *lhs_expr, *rhs_expr;
+   s_list       *mask_list;
+
+   s_pattern pat4[] = { "assign",            mask_list, lhs_expr, rhs_expr };
+   s_pattern pat5[] = { "assign", cond_expr, mask_list, lhs_expr, rhs_expr };
+   if (!MATCH(expr, pat4) && !MATCH(expr, pat5)) {
+      ir_read_error(expr, "expected (assign [<condition>] (<write mask>) "
+			  "<lhs> <rhs>)");
+      return NULL;
+   }
+
+   ir_rvalue *condition = NULL;
+   if (cond_expr != NULL) {
+      condition = read_rvalue(cond_expr);
+      if (condition == NULL) {
+	 ir_read_error(NULL, "when reading condition of assignment");
+	 return NULL;
+      }
+   }
+
+   unsigned mask = 0;
+
+   s_symbol *mask_symbol;
+   s_pattern mask_pat[] = { mask_symbol };
+   if (MATCH(mask_list, mask_pat)) {
+      const char *mask_str = mask_symbol->value();
+      unsigned mask_length = strlen(mask_str);
+      if (mask_length > 4) {
+	 ir_read_error(expr, "invalid write mask: %s", mask_str);
+	 return NULL;
+      }
+
+      const unsigned idx_map[] = { 3, 0, 1, 2 }; /* w=bit 3, x=0, y=1, z=2 */
+
+      for (unsigned i = 0; i < mask_length; i++) {
+	 if (mask_str[i] < 'w' || mask_str[i] > 'z') {
+	    ir_read_error(expr, "write mask contains invalid character: %c",
+			  mask_str[i]);
+	    return NULL;
+	 }
+	 mask |= 1 << idx_map[mask_str[i] - 'w'];
+      }
+   } else if (!mask_list->subexpressions.is_empty()) {
+      ir_read_error(mask_list, "expected () or (<write mask>)");
+      return NULL;
+   }
+
+   ir_dereference *lhs = read_dereference(lhs_expr);
+   if (lhs == NULL) {
+      ir_read_error(NULL, "when reading left-hand side of assignment");
+      return NULL;
+   }
+
+   ir_rvalue *rhs = read_rvalue(rhs_expr);
+   if (rhs == NULL) {
+      ir_read_error(NULL, "when reading right-hand side of assignment");
+      return NULL;
+   }
+
+   if (mask == 0 && (lhs->type->is_vector() || lhs->type->is_scalar())) {
+      ir_read_error(expr, "non-zero write mask required.");
+      return NULL;
+   }
+
+   return new(mem_ctx) ir_assignment(lhs, rhs, condition, mask);
+}
+
+ir_call *
+ir_reader::read_call(s_expression *expr)
+{
+   s_symbol *name;
+   s_list *params;
+
+   s_pattern pat[] = { "call", name, params };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (call <name> (<param> ...))");
+      return NULL;
+   }
+
+   exec_list parameters;
+
+   foreach_iter(exec_list_iterator, it, params->subexpressions) {
+      s_expression *expr = (s_expression*) it.get();
+      ir_rvalue *param = read_rvalue(expr);
+      if (param == NULL) {
+	 ir_read_error(expr, "when reading parameter to function call");
+	 return NULL;
+      }
+      parameters.push_tail(param);
+   }
+
+   ir_function *f = state->symbols->get_function(name->value());
+   if (f == NULL) {
+      ir_read_error(expr, "found call to undefined function %s",
+		    name->value());
+      return NULL;
+   }
+
+   ir_function_signature *callee = f->matching_signature(&parameters);
+   if (callee == NULL) {
+      ir_read_error(expr, "couldn't find matching signature for function "
+                    "%s", name->value());
+      return NULL;
+   }
+
+   return new(mem_ctx) ir_call(callee, &parameters);
+}
+
+ir_expression *
+ir_reader::read_expression(s_expression *expr)
+{
+   s_expression *s_type;
+   s_symbol *s_op;
+   s_expression *s_arg1;
+
+   s_pattern pat[] = { "expression", s_type, s_op, s_arg1 };
+   if (!PARTIAL_MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (expression <type> <operator> "
+			  "<operand> [<operand>])");
+      return NULL;
+   }
+   s_expression *s_arg2 = (s_expression *) s_arg1->next; // may be tail sentinel
+
+   const glsl_type *type = read_type(s_type);
+   if (type == NULL)
+      return NULL;
+
+   /* Read the operator */
+   ir_expression_operation op = ir_expression::get_operator(s_op->value());
+   if (op == (ir_expression_operation) -1) {
+      ir_read_error(expr, "invalid operator: %s", s_op->value());
+      return NULL;
+   }
+    
+   unsigned num_operands = ir_expression::get_num_operands(op);
+   if (num_operands == 1 && !s_arg1->next->is_tail_sentinel()) {
+      ir_read_error(expr, "expected (expression <type> %s <operand>)",
+		    s_op->value());
+      return NULL;
+   }
+
+   ir_rvalue *arg1 = read_rvalue(s_arg1);
+   ir_rvalue *arg2 = NULL;
+   if (arg1 == NULL) {
+      ir_read_error(NULL, "when reading first operand of %s", s_op->value());
+      return NULL;
+   }
+
+   if (num_operands == 2) {
+      if (s_arg2->is_tail_sentinel() || !s_arg2->next->is_tail_sentinel()) {
+	 ir_read_error(expr, "expected (expression <type> %s <operand> "
+			     "<operand>)", s_op->value());
+	 return NULL;
+      }
+      arg2 = read_rvalue(s_arg2);
+      if (arg2 == NULL) {
+	 ir_read_error(NULL, "when reading second operand of %s",
+		       s_op->value());
+	 return NULL;
+      }
+   }
+
+   return new(mem_ctx) ir_expression(op, type, arg1, arg2);
+}
+
+ir_swizzle *
+ir_reader::read_swizzle(s_expression *expr)
+{
+   s_symbol *swiz;
+   s_expression *sub;
+
+   s_pattern pat[] = { "swiz", swiz, sub };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (swiz <swizzle> <rvalue>)");
+      return NULL;
+   }
+
+   if (strlen(swiz->value()) > 4) {
+      ir_read_error(expr, "expected a valid swizzle; found %s", swiz->value());
+      return NULL;
+   }
+
+   ir_rvalue *rvalue = read_rvalue(sub);
+   if (rvalue == NULL)
+      return NULL;
+
+   ir_swizzle *ir = ir_swizzle::create(rvalue, swiz->value(),
+				       rvalue->type->vector_elements);
+   if (ir == NULL)
+      ir_read_error(expr, "invalid swizzle");
+
+   return ir;
+}
+
+ir_constant *
+ir_reader::read_constant(s_expression *expr)
+{
+   s_expression *type_expr;
+   s_list *values;
+
+   s_pattern pat[] = { "constant", type_expr, values };
+   if (!MATCH(expr, pat)) {
+      ir_read_error(expr, "expected (constant <type> (...))");
+      return NULL;
+   }
+
+   const glsl_type *type = read_type(type_expr);
+   if (type == NULL)
+      return NULL;
+
+   if (values == NULL) {
+      ir_read_error(expr, "expected (constant <type> (...))");
+      return NULL;
+   }
+
+   if (type->is_array()) {
+      unsigned elements_supplied = 0;
+      exec_list elements;
+      foreach_iter(exec_list_iterator, it, values->subexpressions) {
+	 s_expression *elt = (s_expression *) it.get();
+	 ir_constant *ir_elt = read_constant(elt);
+	 if (ir_elt == NULL)
+	    return NULL;
+	 elements.push_tail(ir_elt);
+	 elements_supplied++;
+      }
+
+      if (elements_supplied != type->length) {
+	 ir_read_error(values, "expected exactly %u array elements, "
+		       "given %u", type->length, elements_supplied);
+	 return NULL;
+      }
+      return new(mem_ctx) ir_constant(type, &elements);
+   }
+
+   const glsl_type *const base_type = type->get_base_type();
+
+   ir_constant_data data = { { 0 } };
+
+   // Read in list of values (at most 16).
+   int k = 0;
+   foreach_iter(exec_list_iterator, it, values->subexpressions) {
+      if (k >= 16) {
+	 ir_read_error(values, "expected at most 16 numbers");
+	 return NULL;
+      }
+
+      s_expression *expr = (s_expression*) it.get();
+
+      if (base_type->base_type == GLSL_TYPE_FLOAT) {
+	 s_number *value = SX_AS_NUMBER(expr);
+	 if (value == NULL) {
+	    ir_read_error(values, "expected numbers");
+	    return NULL;
+	 }
+	 data.f[k] = value->fvalue();
+      } else {
+	 s_int *value = SX_AS_INT(expr);
+	 if (value == NULL) {
+	    ir_read_error(values, "expected integers");
+	    return NULL;
+	 }
+
+	 switch (base_type->base_type) {
+	 case GLSL_TYPE_UINT: {
+	    data.u[k] = value->value();
+	    break;
+	 }
+	 case GLSL_TYPE_INT: {
+	    data.i[k] = value->value();
+	    break;
+	 }
+	 case GLSL_TYPE_BOOL: {
+	    data.b[k] = value->value();
+	    break;
+	 }
+	 default:
+	    ir_read_error(values, "unsupported constant type");
+	    return NULL;
+	 }
+      }
+      ++k;
+   }
+
+   return new(mem_ctx) ir_constant(type, &data);
+}
+
+ir_dereference *
+ir_reader::read_dereference(s_expression *expr)
+{
+   s_symbol *s_var;
+   s_expression *s_subject;
+   s_expression *s_index;
+   s_symbol *s_field;
+
+   s_pattern var_pat[] = { "var_ref", s_var };
+   s_pattern array_pat[] = { "array_ref", s_subject, s_index };
+   s_pattern record_pat[] = { "record_ref", s_subject, s_field };
+
+   if (MATCH(expr, var_pat)) {
+      ir_variable *var = state->symbols->get_variable(s_var->value());
+      if (var == NULL) {
+	 ir_read_error(expr, "undeclared variable: %s", s_var->value());
+	 return NULL;
+      }
+      return new(mem_ctx) ir_dereference_variable(var);
+   } else if (MATCH(expr, array_pat)) {
+      ir_rvalue *subject = read_rvalue(s_subject);
+      if (subject == NULL) {
+	 ir_read_error(NULL, "when reading the subject of an array_ref");
+	 return NULL;
+      }
+
+      ir_rvalue *idx = read_rvalue(s_index);
+      if (subject == NULL) {
+	 ir_read_error(NULL, "when reading the index of an array_ref");
+	 return NULL;
+      }
+      return new(mem_ctx) ir_dereference_array(subject, idx);
+   } else if (MATCH(expr, record_pat)) {
+      ir_rvalue *subject = read_rvalue(s_subject);
+      if (subject == NULL) {
+	 ir_read_error(NULL, "when reading the subject of a record_ref");
+	 return NULL;
+      }
+      return new(mem_ctx) ir_dereference_record(subject, s_field->value());
+   }
+   return NULL;
+}
+
+ir_texture *
+ir_reader::read_texture(s_expression *expr)
+{
+   s_symbol *tag = NULL;
+   s_expression *s_type = NULL;
+   s_expression *s_sampler = NULL;
+   s_expression *s_coord = NULL;
+   s_expression *s_offset = NULL;
+   s_expression *s_proj = NULL;
+   s_list *s_shadow = NULL;
+   s_expression *s_lod = NULL;
+
+   ir_texture_opcode op = ir_tex; /* silence warning */
+
+   s_pattern tex_pattern[] =
+      { "tex", s_type, s_sampler, s_coord, s_offset, s_proj, s_shadow };
+   s_pattern txf_pattern[] =
+      { "txf", s_type, s_sampler, s_coord, s_offset, s_lod };
+   s_pattern other_pattern[] =
+      { tag, s_type, s_sampler, s_coord, s_offset, s_proj, s_shadow, s_lod };
+
+   if (MATCH(expr, tex_pattern)) {
+      op = ir_tex;
+   } else if (MATCH(expr, txf_pattern)) {
+      op = ir_txf;
+   } else if (MATCH(expr, other_pattern)) {
+      op = ir_texture::get_opcode(tag->value());
+      if (op == -1)
+	 return NULL;
+   } else {
+      ir_read_error(NULL, "unexpected texture pattern");
+      return NULL;
+   }
+
+   ir_texture *tex = new(mem_ctx) ir_texture(op);
+
+   // Read return type
+   const glsl_type *type = read_type(s_type);
+   if (type == NULL) {
+      ir_read_error(NULL, "when reading type in (%s ...)",
+		    tex->opcode_string());
+      return NULL;
+   }
+
+   // Read sampler (must be a deref)
+   ir_dereference *sampler = read_dereference(s_sampler);
+   if (sampler == NULL) {
+      ir_read_error(NULL, "when reading sampler in (%s ...)",
+		    tex->opcode_string());
+      return NULL;
+   }
+   tex->set_sampler(sampler, type);
+
+   // Read coordinate (any rvalue)
+   tex->coordinate = read_rvalue(s_coord);
+   if (tex->coordinate == NULL) {
+      ir_read_error(NULL, "when reading coordinate in (%s ...)",
+		    tex->opcode_string());
+      return NULL;
+   }
+
+   // Read texel offset - either 0 or an rvalue.
+   s_int *si_offset = SX_AS_INT(s_offset);
+   if (si_offset == NULL || si_offset->value() != 0) {
+      tex->offset = read_rvalue(s_offset);
+      if (tex->offset == NULL) {
+	 ir_read_error(s_offset, "expected 0 or an expression");
+	 return NULL;
+      }
+   }
+
+   if (op != ir_txf) {
+      s_int *proj_as_int = SX_AS_INT(s_proj);
+      if (proj_as_int && proj_as_int->value() == 1) {
+	 tex->projector = NULL;
+      } else {
+	 tex->projector = read_rvalue(s_proj);
+	 if (tex->projector == NULL) {
+	    ir_read_error(NULL, "when reading projective divide in (%s ..)",
+	                  tex->opcode_string());
+	    return NULL;
+	 }
+      }
+
+      if (s_shadow->subexpressions.is_empty()) {
+	 tex->shadow_comparitor = NULL;
+      } else {
+	 tex->shadow_comparitor = read_rvalue(s_shadow);
+	 if (tex->shadow_comparitor == NULL) {
+	    ir_read_error(NULL, "when reading shadow comparitor in (%s ..)",
+			  tex->opcode_string());
+	    return NULL;
+	 }
+      }
+   }
+
+   switch (op) {
+   case ir_txb:
+      tex->lod_info.bias = read_rvalue(s_lod);
+      if (tex->lod_info.bias == NULL) {
+	 ir_read_error(NULL, "when reading LOD bias in (txb ...)");
+	 return NULL;
+      }
+      break;
+   case ir_txl:
+   case ir_txf:
+      tex->lod_info.lod = read_rvalue(s_lod);
+      if (tex->lod_info.lod == NULL) {
+	 ir_read_error(NULL, "when reading LOD in (%s ...)",
+		       tex->opcode_string());
+	 return NULL;
+      }
+      break;
+   case ir_txd: {
+      s_expression *s_dx, *s_dy;
+      s_pattern dxdy_pat[] = { s_dx, s_dy };
+      if (!MATCH(s_lod, dxdy_pat)) {
+	 ir_read_error(s_lod, "expected (dPdx dPdy) in (txd ...)");
+	 return NULL;
+      }
+      tex->lod_info.grad.dPdx = read_rvalue(s_dx);
+      if (tex->lod_info.grad.dPdx == NULL) {
+	 ir_read_error(NULL, "when reading dPdx in (txd ...)");
+	 return NULL;
+      }
+      tex->lod_info.grad.dPdy = read_rvalue(s_dy);
+      if (tex->lod_info.grad.dPdy == NULL) {
+	 ir_read_error(NULL, "when reading dPdy in (txd ...)");
+	 return NULL;
+      }
+      break;
+   }
+   default:
+      // tex doesn't have any extra parameters.
+      break;
+   };
+   return tex;
+}