path: root/src/mesa/shader/slang/slang_compile.c

/*
 * Mesa 3-D graphics library
 * Version:  6.5.2
 *
 * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
 *
 * 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 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
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file slang_compile.c
 * slang front-end compiler
 * \author Michal Krol
 */

#include "imports.h"
#include "context.h"
#include "program.h"
#include "prog_parameter.h"
#include "grammar_mesa.h"
#include "slang_codegen.h"
#include "slang_compile.h"
#include "slang_preprocess.h"
#include "slang_storage.h"
#include "slang_error.h"
#include "slang_emit.h"
#include "slang_vartable.h"

#include "slang_print.h"

/*
 * This is a straightforward implementation of the slang front-end
 * compiler.  Lots of error-checking functionality is missing but
 * every well-formed shader source should compile successfully and
 * execute as expected. However, some semantically ill-formed shaders
 * may be accepted resulting in undefined behaviour.
 */



/**
 * Allocate storage for a variable of 'size' bytes from given pool.
 * Return the allocated address for the variable.
 */
static GLuint
slang_var_pool_alloc(slang_var_pool * pool, unsigned int size)
{
   const GLuint addr = pool->next_addr;
   pool->next_addr += size;
   return addr;
}

/*
 * slang_code_unit
 */

GLvoid
_slang_code_unit_ctr(slang_code_unit * self,
                     struct slang_code_object_ * object)
{
   _slang_variable_scope_ctr(&self->vars);
   _slang_function_scope_ctr(&self->funs);
   _slang_struct_scope_ctr(&self->structs);
   self->object = object;
}

GLvoid
_slang_code_unit_dtr(slang_code_unit * self)
{
   slang_variable_scope_destruct(&self->vars);
   slang_function_scope_destruct(&self->funs);
   slang_struct_scope_destruct(&self->structs);
}

/*
 * slang_code_object
 */

GLvoid
_slang_code_object_ctr(slang_code_object * self)
{
   GLuint i;

   for (i = 0; i < SLANG_BUILTIN_TOTAL; i++)
      _slang_code_unit_ctr(&self->builtin[i], self);
   _slang_code_unit_ctr(&self->unit, self);
#if 01
   _slang_assembly_file_ctr(&self->assembly);
#endif
   slang_machine_ctr(&self->machine);
   self->varpool.next_addr = 0;
   slang_atom_pool_construct(&self->atompool);
   slang_export_data_table_ctr(&self->expdata);
   self->expdata.atoms = &self->atompool;
   slang_export_code_table_ctr(&self->expcode);
   self->expcode.atoms = &self->atompool;
}

GLvoid
_slang_code_object_dtr(slang_code_object * self)
{
   GLuint i;

   for (i = 0; i < SLANG_BUILTIN_TOTAL; i++)
      _slang_code_unit_dtr(&self->builtin[i]);
   _slang_code_unit_dtr(&self->unit);
#if 01
   slang_assembly_file_destruct(&self->assembly);
#endif
   slang_machine_dtr(&self->machine);
   slang_atom_pool_destruct(&self->atompool);
   slang_export_data_table_dtr(&self->expdata);
   slang_export_code_table_ctr(&self->expcode);
}

/* slang_info_log */

static char *out_of_memory = "Error: Out of memory.\n";

void
slang_info_log_construct(slang_info_log * log)
{
   log->text = NULL;
   log->dont_free_text = 0;
}

void
slang_info_log_destruct(slang_info_log * log)
{
   if (!log->dont_free_text)
      slang_alloc_free(log->text);
}

static int
slang_info_log_message(slang_info_log * log, const char *prefix,
                       const char *msg)
{
   GLuint size;

   if (log->dont_free_text)
      return 0;
   size = slang_string_length(msg) + 2;
   if (prefix != NULL)
      size += slang_string_length(prefix) + 2;
   if (log->text != NULL) {
      GLuint old_len = slang_string_length(log->text);
      log->text = (char *)
	 slang_alloc_realloc(log->text, old_len + 1, old_len + size);
   }
   else {
      log->text = (char *) (slang_alloc_malloc(size));
      if (log->text != NULL)
         log->text[0] = '\0';
   }
   if (log->text == NULL)
      return 0;
   if (prefix != NULL) {
      slang_string_concat(log->text, prefix);
      slang_string_concat(log->text, ": ");
   }
   slang_string_concat(log->text, msg);
   slang_string_concat(log->text, "\n");
   return 1;
}

int
slang_info_log_print(slang_info_log * log, const char *msg, ...)
{
   va_list va;
   char buf[1024];

   va_start(va, msg);
   _mesa_vsprintf(buf, msg, va);
   va_end(va);
   return slang_info_log_message(log, NULL, buf);
}

int
slang_info_log_error(slang_info_log * log, const char *msg, ...)
{
   va_list va;
   char buf[1024];

   va_start(va, msg);
   _mesa_vsprintf(buf, msg, va);
   va_end(va);
   if (slang_info_log_message(log, "Error", buf))
      return 1;
   slang_info_log_memory(log);
   return 0;
}

int
slang_info_log_warning(slang_info_log * log, const char *msg, ...)
{
   va_list va;
   char buf[1024];

   va_start(va, msg);
   _mesa_vsprintf(buf, msg, va);
   va_end(va);
   if (slang_info_log_message(log, "Warning", buf))
      return 1;
   slang_info_log_memory(log);
   return 0;
}

void
slang_info_log_memory(slang_info_log * log)
{
   if (!slang_info_log_message(log, "Error", "Out of memory.")) {
      log->dont_free_text = 1;
      log->text = out_of_memory;
   }
   abort();
}

/* slang_parse_ctx */

typedef struct slang_parse_ctx_
{
   const byte *I;
   slang_info_log *L;
   int parsing_builtin;
   GLboolean global_scope;   /**< Is object being declared a global? */
   slang_atom_pool *atoms;
   slang_unit_type type;     /**< Vertex vs. Fragment */
} slang_parse_ctx;

/* slang_output_ctx */

typedef struct slang_output_ctx_
{
   slang_variable_scope *vars;
   slang_function_scope *funs;
   slang_struct_scope *structs;
   slang_assembly_file *assembly;
   slang_var_pool *global_pool;
   slang_machine *machine;
   struct gl_program *program;
   slang_var_table *vartable;
} slang_output_ctx;

/* _slang_compile() */

static void
parse_identifier_str(slang_parse_ctx * C, char **id)
{
   *id = (char *) C->I;
   C->I += _mesa_strlen(*id) + 1;
}

static slang_atom
parse_identifier(slang_parse_ctx * C)
{
   const char *id;

   id = (const char *) C->I;
   C->I += _mesa_strlen(id) + 1;
   return slang_atom_pool_atom(C->atoms, id);
}

static int
parse_number(slang_parse_ctx * C, int *number)
{
   const int radix = (int) (*C->I++);
   *number = 0;
   while (*C->I != '\0') {
      int digit;
      if (*C->I >= '0' && *C->I <= '9')
         digit = (int) (*C->I - '0');
      else if (*C->I >= 'A' && *C->I <= 'Z')
         digit = (int) (*C->I - 'A') + 10;
      else
         digit = (int) (*C->I - 'a') + 10;
      *number = *number * radix + digit;
      C->I++;
   }
   C->I++;
   if (*number > 65535)
      slang_info_log_warning(C->L, "%d: literal integer overflow.", *number);
   return 1;
}

static int
parse_float(slang_parse_ctx * C, float *number)
{
   char *integral = NULL;
   char *fractional = NULL;
   char *exponent = NULL;
   char *whole = NULL;

   parse_identifier_str(C, &integral);
   parse_identifier_str(C, &fractional);
   parse_identifier_str(C, &exponent);

   whole = (char *) (slang_alloc_malloc((_mesa_strlen(integral) +
                                         _mesa_strlen(fractional) +
                                         _mesa_strlen(exponent) + 3) * sizeof(char)));
   if (whole == NULL) {
      slang_info_log_memory(C->L);
      return 0;
   }

   slang_string_copy(whole, integral);
   slang_string_concat(whole, ".");
   slang_string_concat(whole, fractional);
   slang_string_concat(whole, "E");
   slang_string_concat(whole, exponent);

   *number = (float) (_mesa_strtod(whole, (char **) NULL));

   slang_alloc_free(whole);
   return 1;
}

/* revision number - increment after each change affecting emitted output */
#define REVISION 3

static int
check_revision(slang_parse_ctx * C)
{
   if (*C->I != REVISION) {
      slang_info_log_error(C->L, "Internal compiler error.");
      return 0;
   }
   C->I++;
   return 1;
}

static int parse_statement(slang_parse_ctx *, slang_output_ctx *,
                           slang_operation *);
static int parse_expression(slang_parse_ctx *, slang_output_ctx *,
                            slang_operation *);
static int parse_type_specifier(slang_parse_ctx *, slang_output_ctx *,
                                slang_type_specifier *);

static GLboolean
parse_array_len(slang_parse_ctx * C, slang_output_ctx * O, GLuint * len)
{
   slang_operation array_size;
   slang_assembly_name_space space;
   GLboolean result;

   if (!slang_operation_construct(&array_size))
      return GL_FALSE;
   if (!parse_expression(C, O, &array_size)) {
      slang_operation_destruct(&array_size);
      return GL_FALSE;
   }

   space.funcs = O->funs;
   space.structs = O->structs;
   space.vars = O->vars;
   result = _slang_evaluate_int(O->assembly, O->machine, &space,
                                &array_size, len, C->atoms);
   slang_operation_destruct(&array_size);
   return result;
}

static GLboolean
calculate_var_size(slang_parse_ctx * C, slang_output_ctx * O,
                   slang_variable * var)
{
   slang_storage_aggregate agg;

   if (!slang_storage_aggregate_construct(&agg))
      return GL_FALSE;
   if (!_slang_aggregate_variable(&agg, &var->type.specifier, var->array_len,
                                  O->funs, O->structs, O->vars, O->machine,
                                  O->assembly, C->atoms)) {
      slang_storage_aggregate_destruct(&agg);
      return GL_FALSE;
   }
   var->size = _slang_sizeof_aggregate(&agg);
   slang_storage_aggregate_destruct(&agg);
   return GL_TRUE;
}

static GLboolean
convert_to_array(slang_parse_ctx * C, slang_variable * var,
                 const slang_type_specifier * sp)
{
   /* sized array - mark it as array, copy the specifier to the array element and
    * parse the expression */
   var->type.specifier.type = slang_spec_array;
   var->type.specifier._array = (slang_type_specifier *)
      slang_alloc_malloc(sizeof(slang_type_specifier));
   if (var->type.specifier._array == NULL) {
      slang_info_log_memory(C->L);
      return GL_FALSE;
   }
   slang_type_specifier_ctr(var->type.specifier._array);
   return slang_type_specifier_copy(var->type.specifier._array, sp);
}

/* structure field */
#define FIELD_NONE 0
#define FIELD_NEXT 1
#define FIELD_ARRAY 2

static GLboolean
parse_struct_field_var(slang_parse_ctx * C, slang_output_ctx * O,
                       slang_variable * var, const slang_type_specifier * sp)
{
   var->a_name = parse_identifier(C);
   if (var->a_name == SLANG_ATOM_NULL)
      return GL_FALSE;

   switch (*C->I++) {
   case FIELD_NONE:
      if (!slang_type_specifier_copy(&var->type.specifier, sp))
         return GL_FALSE;
      break;
   case FIELD_ARRAY:
      if (!convert_to_array(C, var, sp))
         return GL_FALSE;
      if (!parse_array_len(C, O, &var->array_len))
         return GL_FALSE;
      break;
   default:
      return GL_FALSE;
   }

   return calculate_var_size(C, O, var);
}

static int
parse_struct_field(slang_parse_ctx * C, slang_output_ctx * O,
                   slang_struct * st, slang_type_specifier * sp)
{
   slang_output_ctx o = *O;

   o.structs = st->structs;
   if (!parse_type_specifier(C, &o, sp))
      return 0;

   do {
      slang_variable *var = slang_variable_scope_grow(st->fields);
      if (!var) {
         slang_info_log_memory(C->L);
         return 0;
      }
      if (!parse_struct_field_var(C, &o, var, sp))
         return 0;
   }
   while (*C->I++ != FIELD_NONE);

   return 1;
}

static int
parse_struct(slang_parse_ctx * C, slang_output_ctx * O, slang_struct ** st)
{
   slang_atom a_name;
   const char *name;

   /* parse struct name (if any) and make sure it is unique in current scope */
   a_name = parse_identifier(C);
   if (a_name == SLANG_ATOM_NULL)
      return 0;

   name = slang_atom_pool_id(C->atoms, a_name);
   if (name[0] != '\0'
       && slang_struct_scope_find(O->structs, a_name, 0) != NULL) {
      slang_info_log_error(C->L, "%s: duplicate type name.", name);
      return 0;
   }

   /* set-up a new struct */
   *st = (slang_struct *) slang_alloc_malloc(sizeof(slang_struct));
   if (*st == NULL) {
      slang_info_log_memory(C->L);
      return 0;
   }
   if (!slang_struct_construct(*st)) {
      slang_alloc_free(*st);
      *st = NULL;
      slang_info_log_memory(C->L);
      return 0;
   }
   (**st).a_name = a_name;
   (**st).structs->outer_scope = O->structs;

   /* parse individual struct fields */
   do {
      slang_type_specifier sp;

      slang_type_specifier_ctr(&sp);
      if (!parse_struct_field(C, O, *st, &sp)) {
         slang_type_specifier_dtr(&sp);
         return 0;
      }
      slang_type_specifier_dtr(&sp);
   }
   while (*C->I++ != FIELD_NONE);

   /* if named struct, copy it to current scope */
   if (name[0] != '\0') {
      slang_struct *s;

      O->structs->structs =
         (slang_struct *) slang_alloc_realloc(O->structs->structs,
                                              O->structs->num_structs *
                                              sizeof(slang_struct),
                                              (O->structs->num_structs +
                                               1) * sizeof(slang_struct));
      if (O->structs->structs == NULL) {
         slang_info_log_memory(C->L);
         return 0;
      }
      s = &O->structs->structs[O->structs->num_structs];
      if (!slang_struct_construct(s))
         return 0;
      O->structs->num_structs++;
      if (!slang_struct_copy(s, *st))
         return 0;
   }

   return 1;
}


/* type qualifier */
#define TYPE_QUALIFIER_NONE 0
#define TYPE_QUALIFIER_CONST 1
#define TYPE_QUALIFIER_ATTRIBUTE 2
#define TYPE_QUALIFIER_VARYING 3
#define TYPE_QUALIFIER_UNIFORM 4
#define TYPE_QUALIFIER_FIXEDOUTPUT 5
#define TYPE_QUALIFIER_FIXEDINPUT 6

static int
parse_type_qualifier(slang_parse_ctx * C, slang_type_qualifier * qual)
{
   switch (*C->I++) {
   case TYPE_QUALIFIER_NONE:
      *qual = slang_qual_none;
      break;
   case TYPE_QUALIFIER_CONST:
      *qual = slang_qual_const;
      break;
   case TYPE_QUALIFIER_ATTRIBUTE:
      *qual = slang_qual_attribute;
      break;
   case TYPE_QUALIFIER_VARYING:
      *qual = slang_qual_varying;
      break;
   case TYPE_QUALIFIER_UNIFORM:
      *qual = slang_qual_uniform;
      break;
   case TYPE_QUALIFIER_FIXEDOUTPUT:
      *qual = slang_qual_fixedoutput;
      break;
   case TYPE_QUALIFIER_FIXEDINPUT:
      *qual = slang_qual_fixedinput;
      break;
   default:
      return 0;
   }
   return 1;
}

/* type specifier */
#define TYPE_SPECIFIER_VOID 0
#define TYPE_SPECIFIER_BOOL 1
#define TYPE_SPECIFIER_BVEC2 2
#define TYPE_SPECIFIER_BVEC3 3
#define TYPE_SPECIFIER_BVEC4 4
#define TYPE_SPECIFIER_INT 5
#define TYPE_SPECIFIER_IVEC2 6
#define TYPE_SPECIFIER_IVEC3 7
#define TYPE_SPECIFIER_IVEC4 8
#define TYPE_SPECIFIER_FLOAT 9
#define TYPE_SPECIFIER_VEC2 10
#define TYPE_SPECIFIER_VEC3 11
#define TYPE_SPECIFIER_VEC4 12
#define TYPE_SPECIFIER_MAT2 13
#define TYPE_SPECIFIER_MAT3 14
#define TYPE_SPECIFIER_MAT4 15
#define TYPE_SPECIFIER_SAMPLER1D 16
#define TYPE_SPECIFIER_SAMPLER2D 17
#define TYPE_SPECIFIER_SAMPLER3D 18
#define TYPE_SPECIFIER_SAMPLERCUBE 19
#define TYPE_SPECIFIER_SAMPLER1DSHADOW 20
#define TYPE_SPECIFIER_SAMPLER2DSHADOW 21
#define TYPE_SPECIFIER_STRUCT 22
#define TYPE_SPECIFIER_TYPENAME 23

static int
parse_type_specifier(slang_parse_ctx * C, slang_output_ctx * O,
                     slang_type_specifier * spec)
{
   switch (*C->I++) {
   case TYPE_SPECIFIER_VOID:
      spec->type = slang_spec_void;
      break;
   case TYPE_SPECIFIER_BOOL:
      spec->type = slang_spec_bool;
      break;
   case TYPE_SPECIFIER_BVEC2:
      spec->type = slang_spec_bvec2;
      break;
   case TYPE_SPECIFIER_BVEC3:
      spec->type = slang_spec_bvec3;
      break;
   case TYPE_SPECIFIER_BVEC4:
      spec->type = slang_spec_bvec4;
      break;
   case TYPE_SPECIFIER_INT:
      spec->type = slang_spec_int;
      break;
   case TYPE_SPECIFIER_IVEC2:
      spec->type = slang_spec_ivec2;
      break;
   case TYPE_SPECIFIER_IVEC3:
      spec->type = slang_spec_ivec3;
      break;
   case TYPE_SPECIFIER_IVEC4:
      spec->type = slang_spec_ivec4;
      break;
   case TYPE_SPECIFIER_FLOAT:
      spec->type = slang_spec_float;
      break;
   case TYPE_SPECIFIER_VEC2:
      spec->type = slang_spec_vec2;
      break;
   case TYPE_SPECIFIER_VEC3:
      spec->type = slang_spec_vec3;
      break;
   case TYPE_SPECIFIER_VEC4:
      spec->type = slang_spec_vec4;
      break;
   case TYPE_SPECIFIER_MAT2:
      spec->type = slang_spec_mat2;
      break;
   case TYPE_SPECIFIER_MAT3:
      spec->type = slang_spec_mat3;
      break;
   case TYPE_SPECIFIER_MAT4:
      spec->type = slang_spec_mat4;
      break;
   case TYPE_SPECIFIER_SAMPLER1D:
      spec->type = slang_spec_sampler1D;
      break;
   case TYPE_SPECIFIER_SAMPLER2D:
      spec->type = slang_spec_sampler2D;
      break;
   case TYPE_SPECIFIER_SAMPLER3D:
      spec->type = slang_spec_sampler3D;
      break;
   case TYPE_SPECIFIER_SAMPLERCUBE:
      spec->type = slang_spec_samplerCube;
      break;
   case TYPE_SPECIFIER_SAMPLER1DSHADOW:
      spec->type = slang_spec_sampler1DShadow;
      break;
   case TYPE_SPECIFIER_SAMPLER2DSHADOW:
      spec->type = slang_spec_sampler2DShadow;
      break;
   case TYPE_SPECIFIER_STRUCT:
      spec->type = slang_spec_struct;
      if (!parse_struct(C, O, &spec->_struct))
         return 0;
      break;
   case TYPE_SPECIFIER_TYPENAME:
      spec->type = slang_spec_struct;
      {
         slang_atom a_name;
         slang_struct *stru;

         a_name = parse_identifier(C);
         if (a_name == NULL)
            return 0;

         stru = slang_struct_scope_find(O->structs, a_name, 1);
         if (stru == NULL) {
            slang_info_log_error(C->L, "undeclared type name '%s'",
                                 slang_atom_pool_id(C->atoms, a_name));
            return 0;
         }

         spec->_struct =
            (slang_struct *) slang_alloc_malloc(sizeof(slang_struct));
         if (spec->_struct == NULL) {
            slang_info_log_memory(C->L);
            return 0;
         }
         if (!slang_struct_construct(spec->_struct)) {
            slang_alloc_free(spec->_struct);
            spec->_struct = NULL;
            return 0;
         }
         if (!slang_struct_copy(spec->_struct, stru))
            return 0;
      }
      break;
   default:
      return 0;
   }
   return 1;
}

static int
parse_fully_specified_type(slang_parse_ctx * C, slang_output_ctx * O,
                           slang_fully_specified_type * type)
{
   if (!parse_type_qualifier(C, &type->qualifier))
      return 0;
   if (!parse_type_specifier(C, O, &type->specifier))
      return 0;
   return 1;
}

/* operation */
#define OP_END 0
#define OP_BLOCK_BEGIN_NO_NEW_SCOPE 1
#define OP_BLOCK_BEGIN_NEW_SCOPE 2
#define OP_DECLARE 3
#define OP_ASM 4
#define OP_BREAK 5
#define OP_CONTINUE 6
#define OP_DISCARD 7
#define OP_RETURN 8
#define OP_EXPRESSION 9
#define OP_IF 10
#define OP_WHILE 11
#define OP_DO 12
#define OP_FOR 13
#define OP_PUSH_VOID 14
#define OP_PUSH_BOOL 15
#define OP_PUSH_INT 16
#define OP_PUSH_FLOAT 17
#define OP_PUSH_IDENTIFIER 18
#define OP_SEQUENCE 19
#define OP_ASSIGN 20
#define OP_ADDASSIGN 21
#define OP_SUBASSIGN 22
#define OP_MULASSIGN 23
#define OP_DIVASSIGN 24
/*#define OP_MODASSIGN 25*/
/*#define OP_LSHASSIGN 26*/
/*#define OP_RSHASSIGN 27*/
/*#define OP_ORASSIGN 28*/
/*#define OP_XORASSIGN 29*/
/*#define OP_ANDASSIGN 30*/
#define OP_SELECT 31
#define OP_LOGICALOR 32
#define OP_LOGICALXOR 33
#define OP_LOGICALAND 34
/*#define OP_BITOR 35*/
/*#define OP_BITXOR 36*/
/*#define OP_BITAND 37*/
#define OP_EQUAL 38
#define OP_NOTEQUAL 39
#define OP_LESS 40
#define OP_GREATER 41
#define OP_LESSEQUAL 42
#define OP_GREATEREQUAL 43
/*#define OP_LSHIFT 44*/
/*#define OP_RSHIFT 45*/
#define OP_ADD 46
#define OP_SUBTRACT 47
#define OP_MULTIPLY 48
#define OP_DIVIDE 49
/*#define OP_MODULUS 50*/
#define OP_PREINCREMENT 51
#define OP_PREDECREMENT 52
#define OP_PLUS 53
#define OP_MINUS 54
/*#define OP_COMPLEMENT 55*/
#define OP_NOT 56
#define OP_SUBSCRIPT 57
#define OP_CALL 58
#define OP_FIELD 59
#define OP_POSTINCREMENT 60
#define OP_POSTDECREMENT 61


/**
 * When parsing a compound production, this function is used to parse the
 * children.
 * For example, a a while-loop compound will have two children, the
 * while condition expression and the loop body.  So, this function will
 * be called twice to parse those two sub-expressions.
 * \param C  the parsing context
 * \param O  the output context
 * \param oper  the operation we're parsing
 * \param statement  indicates whether parsing a statement, or expression
 * \return 1 if success, 0 if error
 */
static int
parse_child_operation(slang_parse_ctx * C, slang_output_ctx * O,
                      slang_operation * oper, GLboolean statement)
{
   slang_operation *ch;

   /* grow child array */
   ch = slang_operation_grow(&oper->num_children, &oper->children);
   if (statement)
      return parse_statement(C, O, ch);
   return parse_expression(C, O, ch);
}

static int parse_declaration(slang_parse_ctx * C, slang_output_ctx * O);

static int
parse_statement(slang_parse_ctx * C, slang_output_ctx * O,
                slang_operation * oper)
{
   oper->locals->outer_scope = O->vars;
   switch (*C->I++) {
   case OP_BLOCK_BEGIN_NO_NEW_SCOPE:
      /* parse child statements, do not create new variable scope */
      oper->type = slang_oper_block_no_new_scope;
      while (*C->I != OP_END)
         if (!parse_child_operation(C, O, oper, 1))
            return 0;
      C->I++;
      break;
   case OP_BLOCK_BEGIN_NEW_SCOPE:
      /* parse child statements, create new variable scope */
      {
         slang_output_ctx o = *O;

         oper->type = slang_oper_block_new_scope;
         o.vars = oper->locals;
         while (*C->I != OP_END)
            if (!parse_child_operation(C, &o, oper, 1))
               return 0;
         C->I++;
      }
      break;
   case OP_DECLARE:
      /* local variable declaration, individual declarators are stored as
       * children identifiers
       */
      oper->type = slang_oper_block_no_new_scope;
      {
         const unsigned int first_var = O->vars->num_variables;

         /* parse the declaration, note that there can be zero or more
          * than one declarators
          */
         if (!parse_declaration(C, O))
            return 0;
         if (first_var < O->vars->num_variables) {
            const unsigned int num_vars = O->vars->num_variables - first_var;
            unsigned int i;

            oper->num_children = num_vars;
            oper->children = slang_operation_new(num_vars);
            if (oper->children == NULL) {
               slang_info_log_memory(C->L);
               return 0;
            }
            for (i = first_var; i < O->vars->num_variables; i++) {
               slang_operation *o = &oper->children[i - first_var];
               o->type = slang_oper_variable_decl;
               o->locals->outer_scope = O->vars;
               o->a_id = O->vars->variables[i]->a_name;
            }
         }
      }
      break;
   case OP_ASM:
      /* the __asm statement, parse the mnemonic and all its arguments
       * as expressions
       */
      oper->type = slang_oper_asm;
      oper->a_id = parse_identifier(C);
      if (oper->a_id == SLANG_ATOM_NULL)
         return 0;
      while (*C->I != OP_END) {
         if (!parse_child_operation(C, O, oper, 0))
            return 0;
      }
      C->I++;
      break;
   case OP_BREAK:
      oper->type = slang_oper_break;
      break;
   case OP_CONTINUE:
      oper->type = slang_oper_continue;
      break;
   case OP_DISCARD:
      oper->type = slang_oper_discard;
      break;
   case OP_RETURN:
      oper->type = slang_oper_return;
      if (!parse_child_operation(C, O, oper, 0))
         return 0;
      break;
   case OP_EXPRESSION:
      oper->type = slang_oper_expression;
      if (!parse_child_operation(C, O, oper, 0))
         return 0;
      break;
   case OP_IF:
      oper->type = slang_oper_if;
      if (!parse_child_operation(C, O, oper, 0))
         return 0;
      if (!parse_child_operation(C, O, oper, 1))
         return 0;
      if (!parse_child_operation(C, O, oper, 1))
         return 0;
      break;
   case OP_WHILE:
      {
         slang_output_ctx o = *O;

         oper->type = slang_oper_while;
         o.vars = oper->locals;
         if (!parse_child_operation(C, &o, oper, 1))
            return 0;
         if (!parse_child_operation(C, &o, oper, 1))
            return 0;
      }
      break;
   case OP_DO:
      oper->type = slang_oper_do;
      if (!parse_child_operation(C, O, oper, 1))
         return 0;
      if (!parse_child_operation(C, O, oper, 0))
         return 0;
      break;
   case OP_FOR:
      {
         slang_output_ctx o = *O;

         oper->type = slang_oper_for;
         o.vars = oper->locals;
         if (!parse_child_operation(C, &o, oper, 1))
            return 0;
         if (!parse_child_operation(C, &o, oper, 1))
            return 0;
         if (!parse_child_operation(C, &o, oper, 0))
            return 0;
         if (!parse_child_operation(C, &o, oper, 1))
            return 0;
      }
      break;
   default:
      return 0;
   }
   return 1;
}

static int
handle_nary_expression(slang_parse_ctx * C, slang_operation * op,
                       slang_operation ** ops, unsigned int *total_ops,
                       unsigned int n)
{
   unsigned int i;

   op->children =
      (slang_operation *) slang_alloc_malloc(n * sizeof(slang_operation));
   if (op->children == NULL) {
      slang_info_log_memory(C->L);
      return 0;
   }
   op->num_children = n;

   for (i = 0; i < n; i++)
      op->children[i] = (*ops)[*total_ops - (n + 1 - i)];
   (*ops)[*total_ops - (n + 1)] = (*ops)[*total_ops - 1];
   *total_ops -= n;

   *ops = (slang_operation *)
      slang_alloc_realloc(*ops,
                          (*total_ops + n) * sizeof(slang_operation),
                          *total_ops * sizeof(slang_operation));
   if (*ops == NULL) {
      slang_info_log_memory(C->L);
      return 0;
   }
   return 1;
}

static int
is_constructor_name(const char *name, slang_atom a_name,
                    slang_struct_scope * structs)
{
   if (slang_type_specifier_type_from_string(name) != slang_spec_void)
      return 1;
   return slang_struct_scope_find(structs, a_name, 1) != NULL;
}

static int
parse_expression(slang_parse_ctx * C, slang_output_ctx * O,
                 slang_operation * oper)
{
   slang_operation *ops = NULL;
   unsigned int num_ops = 0;
   int number;

   while (*C->I != OP_END) {
      slang_operation *op;
      const unsigned int op_code = *C->I++;

      /* allocate default operation, becomes a no-op if not used  */
      ops = (slang_operation *)
         slang_alloc_realloc(ops,
                             num_ops * sizeof(slang_operation),
                             (num_ops + 1) * sizeof(slang_operation));
      if (ops == NULL) {
         slang_info_log_memory(C->L);
         return 0;
      }
      op = &ops[num_ops];
      if (!slang_operation_construct(op)) {
         slang_info_log_memory(C->L);
         return 0;
      }
      num_ops++;
      op->locals->outer_scope = O->vars;

      switch (op_code) {
      case OP_PUSH_VOID:
         op->type = slang_oper_void;
         break;
      case OP_PUSH_BOOL:
         op->type = slang_oper_literal_bool;
         if (!parse_number(C, &number))
            return 0;
         op->literal[0] =
         op->literal[1] =
         op->literal[2] =
         op->literal[3] = (GLfloat) number;
         break;
      case OP_PUSH_INT:
         op->type = slang_oper_literal_int;
         if (!parse_number(C, &number))
            return 0;
         op->literal[0] =
         op->literal[1] =
         op->literal[2] =
         op->literal[3] = (GLfloat) number;
         break;
      case OP_PUSH_FLOAT:
         op->type = slang_oper_literal_float;
         if (!parse_float(C, &op->literal[0]))
            return 0;
         op->literal[1] =
         op->literal[2] =
         op->literal[3] = op->literal[0];
         break;
      case OP_PUSH_IDENTIFIER:
         op->type = slang_oper_identifier;
         op->a_id = parse_identifier(C);
         if (op->a_id == SLANG_ATOM_NULL)
            return 0;
         break;
      case OP_SEQUENCE:
         op->type = slang_oper_sequence;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_ASSIGN:
         op->type = slang_oper_assign;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_ADDASSIGN:
         op->type = slang_oper_addassign;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_SUBASSIGN:
         op->type = slang_oper_subassign;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_MULASSIGN:
         op->type = slang_oper_mulassign;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_DIVASSIGN:
         op->type = slang_oper_divassign;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
         /*case OP_MODASSIGN: */
         /*case OP_LSHASSIGN: */
         /*case OP_RSHASSIGN: */
         /*case OP_ORASSIGN: */
         /*case OP_XORASSIGN: */
         /*case OP_ANDASSIGN: */
      case OP_SELECT:
         op->type = slang_oper_select;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 3))
            return 0;
         break;
      case OP_LOGICALOR:
         op->type = slang_oper_logicalor;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_LOGICALXOR:
         op->type = slang_oper_logicalxor;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_LOGICALAND:
         op->type = slang_oper_logicaland;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
         /*case OP_BITOR: */
         /*case OP_BITXOR: */
         /*case OP_BITAND: */
      case OP_EQUAL:
         op->type = slang_oper_equal;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_NOTEQUAL:
         op->type = slang_oper_notequal;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_LESS:
         op->type = slang_oper_less;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_GREATER:
         op->type = slang_oper_greater;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_LESSEQUAL:
         op->type = slang_oper_lessequal;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_GREATEREQUAL:
         op->type = slang_oper_greaterequal;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
         /*case OP_LSHIFT: */
         /*case OP_RSHIFT: */
      case OP_ADD:
         op->type = slang_oper_add;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_SUBTRACT:
         op->type = slang_oper_subtract;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_MULTIPLY:
         op->type = slang_oper_multiply;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_DIVIDE:
         op->type = slang_oper_divide;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
         /*case OP_MODULUS: */
      case OP_PREINCREMENT:
         op->type = slang_oper_preincrement;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      case OP_PREDECREMENT:
         op->type = slang_oper_predecrement;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      case OP_PLUS:
         op->type = slang_oper_plus;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      case OP_MINUS:
         op->type = slang_oper_minus;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      case OP_NOT:
         op->type = slang_oper_not;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
         /*case OP_COMPLEMENT: */
      case OP_SUBSCRIPT:
         op->type = slang_oper_subscript;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 2))
            return 0;
         break;
      case OP_CALL:
         op->type = slang_oper_call;
         op->a_id = parse_identifier(C);
         if (op->a_id == SLANG_ATOM_NULL)
            return 0;
         while (*C->I != OP_END)
            if (!parse_child_operation(C, O, op, 0))
               return 0;
         C->I++;

         if (!C->parsing_builtin
             && !slang_function_scope_find_by_name(O->funs, op->a_id, 1)) {
            const char *id;

            id = slang_atom_pool_id(C->atoms, op->a_id);
            if (!is_constructor_name(id, op->a_id, O->structs)) {
               slang_info_log_error(C->L, "%s: undeclared function name.", id);
               return 0;
            }
         }
         break;
      case OP_FIELD:
         op->type = slang_oper_field;
         op->a_id = parse_identifier(C);
         if (op->a_id == SLANG_ATOM_NULL)
            return 0;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      case OP_POSTINCREMENT:
         op->type = slang_oper_postincrement;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      case OP_POSTDECREMENT:
         op->type = slang_oper_postdecrement;
         if (!handle_nary_expression(C, op, &ops, &num_ops, 1))
            return 0;
         break;
      default:
         return 0;
      }
   }
   C->I++;

   *oper = *ops;
   slang_alloc_free(ops);

   return 1;
}

/* parameter qualifier */
#define PARAM_QUALIFIER_IN 0
#define PARAM_QUALIFIER_OUT 1
#define PARAM_QUALIFIER_INOUT 2

/* function parameter array presence */
#define PARAMETER_ARRAY_NOT_PRESENT 0
#define PARAMETER_ARRAY_PRESENT 1

static int
parse_parameter_declaration(slang_parse_ctx * C, slang_output_ctx * O,
                            slang_variable * param)
{
   /* parse and validate the parameter's type qualifiers (there can be
    * two at most) because not all combinations are valid
    */
   if (!parse_type_qualifier(C, &param->type.qualifier))
      return 0;
   switch (*C->I++) {
   case PARAM_QUALIFIER_IN:
      if (param->type.qualifier != slang_qual_const
          && param->type.qualifier != slang_qual_none) {
         slang_info_log_error(C->L, "Invalid type qualifier.");
         return 0;
      }
      break;
   case PARAM_QUALIFIER_OUT:
      if (param->type.qualifier == slang_qual_none)
         param->type.qualifier = slang_qual_out;
      else {
         slang_info_log_error(C->L, "Invalid type qualifier.");
         return 0;
      }
      break;
   case PARAM_QUALIFIER_INOUT:
      if (param->type.qualifier == slang_qual_none)
         param->type.qualifier = slang_qual_inout;
      else {
         slang_info_log_error(C->L, "Invalid type qualifier.");
         return 0;
      }
      break;
   default:
      return 0;
   }

   /* parse parameter's type specifier and name */
   if (!parse_type_specifier(C, O, &param->type.specifier))
      return 0;
   param->a_name = parse_identifier(C);
   if (param->a_name == SLANG_ATOM_NULL)
      return 0;

   /* if the parameter is an array, parse its size (the size must be
    * explicitly defined
    */
   if (*C->I++ == PARAMETER_ARRAY_PRESENT) {
      slang_type_specifier p;

      slang_type_specifier_ctr(&p);
      if (!slang_type_specifier_copy(&p, &param->type.specifier)) {
         slang_type_specifier_dtr(&p);
         return GL_FALSE;
      }
      if (!convert_to_array(C, param, &p)) {
         slang_type_specifier_dtr(&p);
         return GL_FALSE;
      }
      slang_type_specifier_dtr(&p);
      if (!parse_array_len(C, O, &param->array_len))
         return GL_FALSE;
   }

   /* calculate the parameter size */
   if (!calculate_var_size(C, O, param))
      return GL_FALSE;

   /* TODO: allocate the local address here? */
   return 1;
}

/* function type */
#define FUNCTION_ORDINARY 0
#define FUNCTION_CONSTRUCTOR 1
#define FUNCTION_OPERATOR 2

/* function parameter */
#define PARAMETER_NONE 0
#define PARAMETER_NEXT 1

/* operator type */
#define OPERATOR_ADDASSIGN 1
#define OPERATOR_SUBASSIGN 2
#define OPERATOR_MULASSIGN 3
#define OPERATOR_DIVASSIGN 4
/*#define OPERATOR_MODASSIGN 5*/
/*#define OPERATOR_LSHASSIGN 6*/
/*#define OPERATOR_RSHASSIGN 7*/
/*#define OPERATOR_ANDASSIGN 8*/
/*#define OPERATOR_XORASSIGN 9*/
/*#define OPERATOR_ORASSIGN 10*/
#define OPERATOR_LOGICALXOR 11
/*#define OPERATOR_BITOR 12*/
/*#define OPERATOR_BITXOR 13*/
/*#define OPERATOR_BITAND 14*/
#define OPERATOR_LESS 15
#define OPERATOR_GREATER 16
#define OPERATOR_LESSEQUAL 17
#define OPERATOR_GREATEREQUAL 18
/*#define OPERATOR_LSHIFT 19*/
/*#define OPERATOR_RSHIFT 20*/
#define OPERATOR_MULTIPLY 21
#define OPERATOR_DIVIDE 22
/*#define OPERATOR_MODULUS 23*/
#define OPERATOR_INCREMENT 24
#define OPERATOR_DECREMENT 25
#define OPERATOR_PLUS 26
#define OPERATOR_MINUS 27
/*#define OPERATOR_COMPLEMENT 28*/
#define OPERATOR_NOT 29

static const struct
{
   unsigned int o_code;
   const char *o_name;
} operator_names[] = {
   {OPERATOR_INCREMENT, "++"},
   {OPERATOR_ADDASSIGN, "+="},
   {OPERATOR_PLUS, "+"},
   {OPERATOR_DECREMENT, "--"},
   {OPERATOR_SUBASSIGN, "-="},
   {OPERATOR_MINUS, "-"},
   {OPERATOR_NOT, "!"},
   {OPERATOR_MULASSIGN, "*="},
   {OPERATOR_MULTIPLY, "*"},
   {OPERATOR_DIVASSIGN, "/="},
   {OPERATOR_DIVIDE, "/"},
   {OPERATOR_LESSEQUAL, "<="},
   /*{ OPERATOR_LSHASSIGN, "<<=" }, */
   /*{ OPERATOR_LSHIFT, "<<" }, */
   {OPERATOR_LESS, "<"},
   {OPERATOR_GREATEREQUAL, ">="},
   /*{ OPERATOR_RSHASSIGN, ">>=" }, */
   /*{ OPERATOR_RSHIFT, ">>" }, */
   {OPERATOR_GREATER, ">"},
   /*{ OPERATOR_MODASSIGN, "%=" }, */
   /*{ OPERATOR_MODULUS, "%" }, */
   /*{ OPERATOR_ANDASSIGN, "&=" }, */
   /*{ OPERATOR_BITAND, "&" }, */
   /*{ OPERATOR_ORASSIGN, "|=" }, */
   /*{ OPERATOR_BITOR, "|" }, */
   /*{ OPERATOR_COMPLEMENT, "~" }, */
   /*{ OPERATOR_XORASSIGN, "^=" }, */
   {OPERATOR_LOGICALXOR, "^^"},
   /*{ OPERATOR_BITXOR, "^" } */
};

static slang_atom
parse_operator_name(slang_parse_ctx * C)
{
   unsigned int i;

   for (i = 0; i < sizeof(operator_names) / sizeof(*operator_names); i++) {
      if (operator_names[i].o_code == (unsigned int) (*C->I)) {
         slang_atom atom =
            slang_atom_pool_atom(C->atoms, operator_names[i].o_name);
         if (atom == SLANG_ATOM_NULL) {
            slang_info_log_memory(C->L);
            return 0;
         }
         C->I++;
         return atom;
      }
   }
   return 0;
}

static int
parse_function_prototype(slang_parse_ctx * C, slang_output_ctx * O,
                         slang_function * func)
{
   /* parse function type and name */
   if (!parse_fully_specified_type(C, O, &func->header.type))
      return 0;
   switch (*C->I++) {
   case FUNCTION_ORDINARY:
      func->kind = slang_func_ordinary;
      func->header.a_name = parse_identifier(C);
      if (func->header.a_name == SLANG_ATOM_NULL)
         return 0;
      break;
   case FUNCTION_CONSTRUCTOR:
      func->kind = slang_func_constructor;
      if (func->header.type.specifier.type == slang_spec_struct)
         return 0;
      func->header.a_name =
         slang_atom_pool_atom(C->atoms,
                              slang_type_specifier_type_to_string
                              (func->header.type.specifier.type));
      if (func->header.a_name == SLANG_ATOM_NULL) {
         slang_info_log_memory(C->L);
         return 0;
      }
      break;
   case FUNCTION_OPERATOR:
      func->kind = slang_func_operator;
      func->header.a_name = parse_operator_name(C);
      if (func->header.a_name == SLANG_ATOM_NULL)
         return 0;
      break;
   default:
      return 0;
   }

   /* parse function parameters */
   while (*C->I++ == PARAMETER_NEXT) {
      slang_variable *p = slang_variable_scope_grow(func->parameters);
      if (!p) {
         slang_info_log_memory(C->L);
         return 0;
      }
      if (!parse_parameter_declaration(C, O, p))
         return 0;
   }

#if 111
   /* if the function returns a value, append a hidden __retVal 'out'
    * parameter that corresponds to the return value.
    */
   if (_slang_function_has_return_value(func)) {
      slang_variable *p = slang_variable_scope_grow(func->parameters);
      slang_atom a_retVal = slang_atom_pool_atom(C->atoms, "__retVal");
      assert(a_retVal);
      p->a_name = a_retVal;
      p->type = func->header.type;
      p->type.qualifier = slang_qual_out;
   }
#endif

   /* function formal parameters and local variables share the same
    * scope, so save the information about param count in a seperate
    * place also link the scope to the global variable scope so when a
    * given identifier is not found here, the search process continues
    * in the global space
    */
   func->param_count = func->parameters->num_variables;
   func->parameters->outer_scope = O->vars;

   return 1;
}

static int
parse_function_definition(slang_parse_ctx * C, slang_output_ctx * O,
                          slang_function * func)
{
   slang_output_ctx o = *O;

   if (!parse_function_prototype(C, O, func))
      return 0;

   /* create function's body operation */
   func->body =
      (slang_operation *) slang_alloc_malloc(sizeof(slang_operation));
   if (func->body == NULL) {
      slang_info_log_memory(C->L);
      return 0;
   }
   if (!slang_operation_construct(func->body)) {
      slang_alloc_free(func->body);
      func->body = NULL;
      slang_info_log_memory(C->L);
      return 0;
   }

   /* to parse the body the parse context is modified in order to
    * capture parsed variables into function's local variable scope
    */
   C->global_scope = GL_FALSE;
   o.vars = func->parameters;
   if (!parse_statement(C, &o, func->body))
      return 0;

   C->global_scope = GL_TRUE;
   return 1;
}

static GLboolean
initialize_global(slang_assemble_ctx * A, slang_variable * var)
{
#if 01
   slang_assembly_file_restore_point point;
#endif
   slang_machine mach;
   slang_assembly_local_info save_local = A->local;
   slang_operation op_id, op_assign;
   GLboolean result;

#if 01
   /* save the current assembly */
   if (!slang_assembly_file_restore_point_save(A->file, &point))
      return GL_FALSE;
#endif

   /* setup the machine */
   mach = *A->mach;
   mach.ip = A->file->count;

   /* allocate local storage for expression */
   A->local.ret_size = 0;
   A->local.addr_tmp = 0;
   A->local.swizzle_tmp = 4;
   if (!slang_assembly_file_push_label(A->file, slang_asm_local_alloc, 20))
      return GL_FALSE;
   if (!slang_assembly_file_push_label(A->file, slang_asm_enter, 20))
      return GL_FALSE;

   /* construct the left side of assignment */
   if (!slang_operation_construct(&op_id))
      return GL_FALSE;
   op_id.type = slang_oper_identifier;
   op_id.a_id = var->a_name;

   /* put the variable into operation's scope */
   op_id.locals->variables =
      (slang_variable **) slang_alloc_malloc(sizeof(slang_variable *));
   if (op_id.locals->variables == NULL) {
      slang_operation_destruct(&op_id);
      return GL_FALSE;
   }
   op_id.locals->num_variables = 1;
   op_id.locals->variables[0] = var;

   /* construct the assignment expression */
   if (!slang_operation_construct(&op_assign)) {
      op_id.locals->num_variables = 0;
      slang_operation_destruct(&op_id);
      return GL_FALSE;
   }
   op_assign.type = slang_oper_assign;
   op_assign.children =
      (slang_operation *) slang_alloc_malloc(2 * sizeof(slang_operation));
   if (op_assign.children == NULL) {
      slang_operation_destruct(&op_assign);
      op_id.locals->num_variables = 0;
      slang_operation_destruct(&op_id);
      return GL_FALSE;
   }
   op_assign.num_children = 2;
   op_assign.children[0] = op_id;
   op_assign.children[1] = *var->initializer;

#if 0 /* this should go away */
   /* insert the actual expression */
   result = _slang_assemble_operation(A, &op_assign, slang_ref_forbid);
#else
   result = 1;
#endif

   /* carefully destroy the operations */
   op_assign.num_children = 0;
   slang_alloc_free(op_assign.children);
   op_assign.children = NULL;
   slang_operation_destruct(&op_assign);
   op_id.locals->num_variables = 0;
   slang_operation_destruct(&op_id);

   if (!result)
      return GL_FALSE;
   if (!slang_assembly_file_push(A->file, slang_asm_exit))
      return GL_FALSE;

   /* execute the expression */
#if 0
   if (!_slang_execute2(A->file, &mach))
      return GL_FALSE;
#endif

#if 01
   /* restore the old assembly */
   if (!slang_assembly_file_restore_point_load(A->file, &point))
      return GL_FALSE;
#endif
   A->local = save_local;

   /* now we copy the contents of the initialized variable back to the original machine */
   _mesa_memcpy((GLubyte *) A->mach->mem + var->address,
                (GLubyte *) mach.mem + var->address, var->size);

   return GL_TRUE;
}

/* init declarator list */
#define DECLARATOR_NONE 0
#define DECLARATOR_NEXT 1

/* variable declaration */
#define VARIABLE_NONE 0
#define VARIABLE_IDENTIFIER 1
#define VARIABLE_INITIALIZER 2
#define VARIABLE_ARRAY_EXPLICIT 3
#define VARIABLE_ARRAY_UNKNOWN 4


/**
 * Parse the initializer for a variable declaration.
 */
static int
parse_init_declarator(slang_parse_ctx * C, slang_output_ctx * O,
                      const slang_fully_specified_type * type)
{
   slang_variable *var;

   /* empty init declatator (without name, e.g. "float ;") */
   if (*C->I++ == VARIABLE_NONE)
      return 1;

   /* make room for the new variable and initialize it */
   var = slang_variable_scope_grow(O->vars);
   if (!var) {
      slang_info_log_memory(C->L);
      return 0;
   }

   /* copy the declarator qualifier type, parse the identifier */
   var->global = C->global_scope;
   var->type.qualifier = type->qualifier;
   var->a_name = parse_identifier(C);
   if (var->a_name == SLANG_ATOM_NULL)
      return 0;

   switch (*C->I++) {
   case VARIABLE_NONE:
      /* simple variable declarator - just copy the specifier */
      if (!slang_type_specifier_copy(&var->type.specifier, &type->specifier))
         return 0;
      break;
   case VARIABLE_INITIALIZER:
      /* initialized variable - copy the specifier and parse the expression */
      if (!slang_type_specifier_copy(&var->type.specifier, &type->specifier))
         return 0;
      var->initializer =
         (slang_operation *) slang_alloc_malloc(sizeof(slang_operation));
      if (var->initializer == NULL) {
         slang_info_log_memory(C->L);
         return 0;
      }
      if (!slang_operation_construct(var->initializer)) {
         slang_alloc_free(var->initializer);
         var->initializer = NULL;
         slang_info_log_memory(C->L);
         return 0;
      }
      if (!parse_expression(C, O, var->initializer))
         return 0;
      break;
#if 0
   case VARIABLE_ARRAY_UNKNOWN:
      /* unsized array - mark it as array and copy the specifier to
         the array element
      */
      if (!convert_to_array(C, var, &type->specifier))
         return GL_FALSE;
      break;
#endif
   case VARIABLE_ARRAY_EXPLICIT:
      if (!convert_to_array(C, var, &type->specifier))
         return GL_FALSE;
      if (!parse_array_len(C, O, &var->array_len))
         return GL_FALSE;
      break;
   default:
      return 0;
   }

#if 1
   if (C->global_scope) {
      slang_assemble_ctx A;

      A.file = O->assembly;
      A.mach = O->machine;
      A.atoms = C->atoms;
      A.space.funcs = O->funs;
      A.space.structs = O->structs;
      A.space.vars = O->vars;
      A.program = O->program;
#if 0
      A.codegen = O->codegen;
#endif
      A.vartable = O->vartable;

      _slang_codegen_global_variable(&A, var, C->type);
   }
#endif

   /* allocate global address space for a variable with a known size */
   if (C->global_scope
       && !(var->type.specifier.type == slang_spec_array
            && var->array_len == 0)) {
      if (!calculate_var_size(C, O, var))
         return GL_FALSE;
      var->address = slang_var_pool_alloc(O->global_pool, var->size);
   }

   /* initialize global variable */
   if (C->global_scope) {
      if (var->initializer != NULL) {
         slang_assemble_ctx A;

         A.file = O->assembly;
         A.mach = O->machine;
         A.atoms = C->atoms;
         A.space.funcs = O->funs;
         A.space.structs = O->structs;
         A.space.vars = O->vars;
         if (!initialize_global(&A, var))
            return 0;
      }
      else {
         _mesa_memset((GLubyte *) (O->machine->mem) + var->address, 0,
                      var->size);
      }
   }
   return 1;
}

/**
 * Parse a list of variable declarations.  Each variable may have an
 * initializer.
 */
static int
parse_init_declarator_list(slang_parse_ctx * C, slang_output_ctx * O)
{
   slang_fully_specified_type type;

   /* parse the fully specified type, common to all declarators */
   if (!slang_fully_specified_type_construct(&type))
      return 0;
   if (!parse_fully_specified_type(C, O, &type)) {
      slang_fully_specified_type_destruct(&type);
      return 0;
   }

   /* parse declarators, pass-in the parsed type */
   do {
      if (!parse_init_declarator(C, O, &type)) {
         slang_fully_specified_type_destruct(&type);
         return 0;
      }
   }
   while (*C->I++ == DECLARATOR_NEXT);

   slang_fully_specified_type_destruct(&type);
   return 1;
}


/**
 * Parse a function definition or declaration.
 * \param C  parsing context
 * \param O  output context
 * \param definition if non-zero expect a definition, else a declaration
 * \param parsed_func_ret  returns the parsed function
 * \return GL_TRUE if success, GL_FALSE if failure
 */
static GLboolean
parse_function(slang_parse_ctx * C, slang_output_ctx * O, int definition,
               slang_function ** parsed_func_ret)
{
   slang_function parsed_func, *found_func;

   /* parse function definition/declaration */
   if (!slang_function_construct(&parsed_func))
      return GL_FALSE;
   if (definition) {
      if (!parse_function_definition(C, O, &parsed_func)) {
         slang_function_destruct(&parsed_func);
         return GL_FALSE;
      }
   }
   else {
      if (!parse_function_prototype(C, O, &parsed_func)) {
         slang_function_destruct(&parsed_func);
         return GL_FALSE;
      }
   }

   /* find a function with a prototype matching the parsed one - only
    * the current scope is being searched to allow built-in function
    * overriding
    */
   found_func = slang_function_scope_find(O->funs, &parsed_func, 0);
   if (found_func == NULL) {
      /* New function, add it to the function list */
      O->funs->functions =
         (slang_function *) slang_alloc_realloc(O->funs->functions,
                                                O->funs->num_functions *
                                                sizeof(slang_function),
                                                (O->funs->num_functions +
                                                 1) * sizeof(slang_function));
      if (O->funs->functions == NULL) {
         slang_info_log_memory(C->L);
         slang_function_destruct(&parsed_func);
         return GL_FALSE;
      }
      O->funs->functions[O->funs->num_functions] = parsed_func;
      O->funs->num_functions++;

      /* return the newly parsed function */
      *parsed_func_ret = &O->funs->functions[O->funs->num_functions - 1];
   }
   else {
      /* previously defined or declared */
      /* TODO: check function return type qualifiers and specifiers */
      if (definition) {
         if (found_func->body != NULL) {
            slang_info_log_error(C->L, "%s: function already has a body.",
                                 slang_atom_pool_id(C->atoms,
                                                    parsed_func.header.
                                                    a_name));
            slang_function_destruct(&parsed_func);
            return GL_FALSE;
         }

         /* destroy the existing function declaration and replace it
          * with the new one, remember to save the fixup table
          */
         parsed_func.fixups = found_func->fixups;
         slang_fixup_table_init(&found_func->fixups);
         slang_function_destruct(found_func);
         *found_func = parsed_func;
      }
      else {
         /* another declaration of the same function prototype - ignore it */
         slang_function_destruct(&parsed_func);
      }

      /* return the found function */
      *parsed_func_ret = found_func;
   }

   /* assemble the parsed function */
   {
      slang_assemble_ctx A;

      A.file = O->assembly;
      A.mach = O->machine;
      A.atoms = C->atoms;
      A.space.funcs = O->funs;
      A.space.structs = O->structs;
      A.space.vars = O->vars;
      A.program = O->program;
#if 0
      A.codegen = O->codegen;
#endif
      A.vartable = O->vartable;

      _slang_reset_error();

#if 0
      printf("*************** Assemble function %s ****\n", (char *) (*parsed_func_ret)->header.a_name);
      slang_print_var_scope((*parsed_func_ret)->parameters,
                            (*parsed_func_ret)->param_count);
#endif

#if 0
      if (!_slang_assemble_function(&A, *parsed_func_ret)) {
         /* propogate the error message back through the info log */
         C->L->text = _mesa_strdup(_slang_error_text());
         C->L->dont_free_text = GL_FALSE;
         return GL_FALSE;
      }
#endif

#if 0
      printf("**************************************\n");
#endif
#if 1
      _slang_codegen_function(&A, *parsed_func_ret);
#endif
   }
   return GL_TRUE;
}

/* declaration */
#define DECLARATION_FUNCTION_PROTOTYPE 1
#define DECLARATION_INIT_DECLARATOR_LIST 2

static int
parse_declaration(slang_parse_ctx * C, slang_output_ctx * O)
{
   switch (*C->I++) {
   case DECLARATION_INIT_DECLARATOR_LIST:
      if (!parse_init_declarator_list(C, O))
         return 0;
      break;
   case DECLARATION_FUNCTION_PROTOTYPE:
      {
         slang_function *dummy_func;

         if (!parse_function(C, O, 0, &dummy_func))
            return 0;
      }
      break;
   default:
      return 0;
   }
   return 1;
}

/* external declaration */
#define EXTERNAL_NULL 0
#define EXTERNAL_FUNCTION_DEFINITION 1
#define EXTERNAL_DECLARATION 2

static GLboolean
parse_code_unit(slang_parse_ctx * C, slang_code_unit * unit,
                struct gl_program *program)
{
   slang_output_ctx o;
   GLboolean success;

   /* setup output context */
   o.funs = &unit->funs;
   o.structs = &unit->structs;
   o.vars = &unit->vars;
   o.assembly = &unit->object->assembly;
   o.global_pool = &unit->object->varpool;
   o.machine = &unit->object->machine;
   o.program = program;
   o.vartable = _slang_push_var_table(NULL);

   /* parse individual functions and declarations */
   while (*C->I != EXTERNAL_NULL) {
      switch (*C->I++) {
      case EXTERNAL_FUNCTION_DEFINITION:
         {
            slang_function *func;
            success = parse_function(C, &o, 1, &func);
         }
         break;
      case EXTERNAL_DECLARATION:
         success = parse_declaration(C, &o);
         break;
      default:
         success = GL_FALSE;
      }

      if (!success) {
         /* xxx free codegen */
         _slang_pop_var_table(o.vartable);
         return GL_FALSE;
      }
   }
   C->I++;

   _slang_pop_var_table(o.vartable);
   return GL_TRUE;
}

static GLboolean
compile_binary(const byte * prod, slang_code_unit * unit,
               slang_unit_type type, slang_info_log * infolog,
               slang_code_unit * builtin, slang_code_unit * downlink,
               struct gl_program *program)
{
   slang_parse_ctx C;

   unit->type = type;

   /* setup parse context */
   C.I = prod;
   C.L = infolog;
   C.parsing_builtin = (builtin == NULL);
   C.global_scope = GL_TRUE;
   C.atoms = &unit->object->atompool;
   C.type = type;

   if (!check_revision(&C))
      return GL_FALSE;

   if (downlink != NULL) {
      unit->vars.outer_scope = &downlink->vars;
      unit->funs.outer_scope = &downlink->funs;
      unit->structs.outer_scope = &downlink->structs;
   }

   /* parse translation unit */
   return parse_code_unit(&C, unit, program);
}

static GLboolean
compile_with_grammar(grammar id, const char *source, slang_code_unit * unit,
                     slang_unit_type type, slang_info_log * infolog,
                     slang_code_unit * builtin,
                     struct gl_program *program)
{
   byte *prod;
   GLuint size, start, version;
   slang_string preprocessed;

   /* First retrieve the version number. */
   if (!_slang_preprocess_version(source, &version, &start, infolog))
      return GL_FALSE;

   if (version > 110) {
      slang_info_log_error(infolog,
                           "language version specified is not supported.");
      return GL_FALSE;
   }

   /* Now preprocess the source string. */
   slang_string_init(&preprocessed);
   if (!_slang_preprocess_directives(&preprocessed, &source[start], infolog)) {
      slang_string_free(&preprocessed);
      slang_info_log_error(infolog, "failed to preprocess the source.");
      return GL_FALSE;
   }

   /* Finally check the syntax and generate its binary representation. */
   if (!grammar_fast_check(id,
                           (const byte *) (slang_string_cstr(&preprocessed)),
                           &prod, &size,
        65536)) {
      char buf[1024];
      GLint pos;

      slang_string_free(&preprocessed);
      grammar_get_last_error((byte *) (buf), sizeof(buf), &pos);
      slang_info_log_error(infolog, buf);
      RETURN_ERROR("syntax error (possibly in library code)", 0);
   }
   slang_string_free(&preprocessed);

   /* Syntax is okay - translate it to internal representation. */
   if (!compile_binary(prod, unit, type, infolog, builtin,
                       &builtin[SLANG_BUILTIN_TOTAL - 1],
                       program)) {
      grammar_alloc_free(prod);
      return GL_FALSE;
   }
   grammar_alloc_free(prod);
   return GL_TRUE;
}

LONGSTRING static const char *slang_shader_syn =
#include "library/slang_shader_syn.h"
   ;

static const byte slang_core_gc[] = {
#include "library/slang_core_gc.h"
};

static const byte slang_common_builtin_gc[] = {
#include "library/slang_common_builtin_gc.h"
};

static const byte slang_fragment_builtin_gc[] = {
#include "library/slang_fragment_builtin_gc.h"
};

static const byte slang_vertex_builtin_gc[] = {
#include "library/slang_vertex_builtin_gc.h"
};

#if defined(USE_X86_ASM) || defined(SLANG_X86)
foo
static const byte slang_builtin_vec4_gc[] = {
#include "library/slang_builtin_vec4_gc.h"
};
#endif

static GLboolean
compile_object(grammar * id, const char *source, slang_code_object * object,
               slang_unit_type type, slang_info_log * infolog,
               struct gl_program *program)
{
   slang_code_unit *builtins = NULL;

   /* load GLSL grammar */
   *id = grammar_load_from_text((const byte *) (slang_shader_syn));
   if (*id == 0) {
      byte buf[1024];
      int pos;

      grammar_get_last_error(buf, 1024, &pos);
      slang_info_log_error(infolog, (const char *) (buf));
      return GL_FALSE;
   }

   /* set shader type - the syntax is slightly different for different shaders */
   if (type == slang_unit_fragment_shader
       || type == slang_unit_fragment_builtin)
      grammar_set_reg8(*id, (const byte *) "shader_type", 1);
   else
      grammar_set_reg8(*id, (const byte *) "shader_type", 2);

   /* enable language extensions */
   grammar_set_reg8(*id, (const byte *) "parsing_builtin", 1);

   /* if parsing user-specified shader, load built-in library */
   if (type == slang_unit_fragment_shader || type == slang_unit_vertex_shader) {
      /* compile core functionality first */
      if (!compile_binary(slang_core_gc,
                          &object->builtin[SLANG_BUILTIN_CORE],
                          slang_unit_fragment_builtin, infolog,
                          NULL, NULL, NULL))
         return GL_FALSE;

      /* compile common functions and variables, link to core */
      if (!compile_binary(slang_common_builtin_gc,
                          &object->builtin[SLANG_BUILTIN_COMMON],
                          slang_unit_fragment_builtin, infolog, NULL,
                          &object->builtin[SLANG_BUILTIN_CORE], NULL))
         return GL_FALSE;

      /* compile target-specific functions and variables, link to common */
      if (type == slang_unit_fragment_shader) {
         if (!compile_binary(slang_fragment_builtin_gc,
                             &object->builtin[SLANG_BUILTIN_TARGET],
                             slang_unit_fragment_builtin, infolog, NULL,
                             &object->builtin[SLANG_BUILTIN_COMMON], NULL))
            return GL_FALSE;
      }
      else if (type == slang_unit_vertex_shader) {
         if (!compile_binary(slang_vertex_builtin_gc,
                             &object->builtin[SLANG_BUILTIN_TARGET],
                             slang_unit_vertex_builtin, infolog, NULL,
                             &object->builtin[SLANG_BUILTIN_COMMON], NULL))
            return GL_FALSE;
      }

#if defined(USE_X86_ASM) || defined(SLANG_X86)
      /* compile x86 4-component vector overrides, link to target */
      if (!compile_binary(slang_builtin_vec4_gc,
                          &object->builtin[SLANG_BUILTIN_VEC4],
                          slang_unit_fragment_builtin, infolog, NULL,
                          &object->builtin[SLANG_BUILTIN_TARGET]))
         return GL_FALSE;
#endif

      /* disable language extensions */
#if NEW_SLANG /* allow-built-ins */
      grammar_set_reg8(*id, (const byte *) "parsing_builtin", 1);
#else
      grammar_set_reg8(*id, (const byte *) "parsing_builtin", 0);
#endif
      builtins = object->builtin;
   }

   /* compile the actual shader - pass-in built-in library for external shader */
   return compile_with_grammar(*id, source, &object->unit, type, infolog,
                               builtins, program);
}


#if 0
static void
slang_create_uniforms(const slang_export_data_table *exports,
                      struct gl_program *program)
{
   /* XXX only add uniforms that are actually going to get used */
   GLuint i;
   for (i = 0; i < exports->count; i++) {
      if (exports->entries[i].access == slang_exp_uniform) {
         const char *name = (char *) exports->entries[i].quant.name;
         GLint j = _mesa_add_uniform(program->Parameters, name, 4);
         assert(j >= 0);
      }
   }
}
#endif


static GLboolean
compile_shader(GLcontext *ctx, slang_code_object * object,
               slang_unit_type type, slang_info_log * infolog,
               struct gl_shader *shader)
{
   struct gl_program *program = shader->Programs[0];
   GLboolean success;
   grammar id = 0;

   assert(program);

   _slang_code_object_dtr(object);
   _slang_code_object_ctr(object);

   success = compile_object(&id, shader->Source, object, type, infolog, program);
   if (id != 0)
      grammar_destroy(id);
   if (!success)
      return GL_FALSE;

   if (!_slang_build_export_data_table(&object->expdata, &object->unit.vars))
      return GL_FALSE;
   if (!_slang_build_export_code_table(&object->expcode, &object->unit.funs,
                                       &object->unit))
      return GL_FALSE;

#if NEW_SLANG
   {
      slang_create_uniforms(&object->expdata, shader);
      _mesa_print_program(program);
      _mesa_print_program_parameters(ctx, program);
   }
#endif

   return GL_TRUE;
}



GLboolean
_slang_compile(GLcontext *ctx, struct gl_shader *shader)
{
   GLboolean success;
   slang_info_log info_log;
   slang_code_object obj;
   slang_unit_type type;

   if (shader->Type == GL_VERTEX_SHADER) {
      type = slang_unit_vertex_shader;
   }
   else {
      assert(shader->Type == GL_FRAGMENT_SHADER);
      type = slang_unit_fragment_shader;
   }

   /* XXX temporary hack */
   if (!shader->Programs) {
      GLenum progTarget;
      if (shader->Type == GL_VERTEX_SHADER)
         progTarget = GL_VERTEX_PROGRAM_ARB;
      else
         progTarget = GL_FRAGMENT_PROGRAM_ARB;
      shader->Programs
         = (struct gl_program **) malloc(sizeof(struct gl_program*));
      shader->Programs[0] = _mesa_new_program(ctx, progTarget, 1);
      shader->NumPrograms = 1;

      shader->Programs[0]->Parameters = _mesa_new_parameter_list();
      shader->Programs[0]->Varying = _mesa_new_parameter_list();
      shader->Programs[0]->Attributes = _mesa_new_parameter_list();
   }

   slang_info_log_construct(&info_log);
   _slang_code_object_ctr(&obj);

   success = compile_shader(ctx, &obj, type, &info_log, shader);

   if (success) {
#if 0
      slang_create_uniforms(&object->expdata, shader);
      _mesa_print_program(program);
      _mesa_print_program_parameters(ctx, program);
#endif
   }
   else {
      /* XXX more work on info log needed here */
      if (info_log.text) {
         if (shader->InfoLog) {
            free(shader->InfoLog);
            shader->InfoLog = NULL;
         }
         shader->InfoLog = strdup(info_log.text);
      }
   }

   slang_info_log_destruct(&info_log);
   _slang_code_object_dtr(&obj);

   return success;
}