ir.cpp

/*
 * 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 <string.h>
#include "main/imports.h"
#include "main/simple_list.h"
#include "ir.h"
#include "glsl_types.h"

ir_assignment::ir_assignment(ir_rvalue *lhs, ir_rvalue *rhs,
			     ir_rvalue *condition)
   : ir_rvalue()
{
   this->lhs = lhs;
   this->rhs = rhs;
   this->condition = condition;
}


ir_expression::ir_expression(int op, const struct glsl_type *type,
			     ir_rvalue *op0, ir_rvalue *op1)
   : ir_rvalue()
{
   this->type = type;
   this->operation = ir_expression_operation(op);
   this->operands[0] = op0;
   this->operands[1] = op1;
}


ir_label::ir_label(const char *label)
   : ir_instruction(), label(label)
{
   /* empty */
}


ir_constant::ir_constant(const struct glsl_type *type, const void *data)
   : ir_rvalue()
{
   unsigned size = 0;

   this->type = type;
   switch (type->base_type) {
   case GLSL_TYPE_UINT:  size = sizeof(this->value.u[0]); break;
   case GLSL_TYPE_INT:   size = sizeof(this->value.i[0]); break;
   case GLSL_TYPE_FLOAT: size = sizeof(this->value.f[0]); break;
   case GLSL_TYPE_BOOL:  size = sizeof(this->value.b[0]); break;
   default:
      /* FINISHME: What to do?  Exceptions are not the answer.
       */
      break;
   }

   memcpy(& this->value, data, size * type->components());
}


ir_dereference::ir_dereference(ir_instruction *var)
   : ir_rvalue()
{
   this->mode = ir_reference_variable;
   this->var = var;
   this->type = (var != NULL) ? var->type : glsl_type::error_type;
}


ir_dereference::ir_dereference(ir_instruction *var,
			       ir_rvalue *array_index)
   : ir_rvalue(), mode(ir_reference_array),
     var(var)
{
   this->type = (var != NULL) ? var->type : glsl_type::error_type;
   this->selector.array_index = array_index;
}


ir_swizzle::ir_swizzle(ir_rvalue *val, unsigned x, unsigned y, unsigned z,
		       unsigned w, unsigned count)
   : val(val)
{
   assert((count >= 1) && (count <= 4));

   const unsigned dup_mask = 0
      | ((count > 1) ? ((1U << y) & ((1U << x)                        )) : 0)
      | ((count > 2) ? ((1U << z) & ((1U << x) | (1U << y)            )) : 0)
      | ((count > 3) ? ((1U << w) & ((1U << x) | (1U << y) | (1U << z))) : 0);

   assert(x <= 3);
   assert(y <= 3);
   assert(z <= 3);
   assert(w <= 3);

   mask.x = x;
   mask.y = y;
   mask.z = z;
   mask.w = w;
   mask.num_components = count;
   mask.has_duplicates = dup_mask != 0;

   /* Based on the number of elements in the swizzle and the base type
    * (i.e., float, int, unsigned, or bool) of the vector being swizzled,
    * generate the type of the resulting value.
    */
   type = glsl_type::get_instance(val->type->base_type, mask.num_components, 1);
}

#define X 1
#define R 5
#define S 9
#define I 13

ir_swizzle *
ir_swizzle::create(ir_rvalue *val, const char *str, unsigned vector_length)
{
   /* For each possible swizzle character, this table encodes the value in
    * \c idx_map that represents the 0th element of the vector.  For invalid
    * swizzle characters (e.g., 'k'), a special value is used that will allow
    * detection of errors.
    */
   static const unsigned char base_idx[26] = {
   /* a  b  c  d  e  f  g  h  i  j  k  l  m */
      R, R, I, I, I, I, R, I, I, I, I, I, I,
   /* n  o  p  q  r  s  t  u  v  w  x  y  z */
      I, I, S, S, R, S, S, I, I, X, X, X, X
   };

   /* Each valid swizzle character has an entry in the previous table.  This
    * table encodes the base index encoded in the previous table plus the actual
    * index of the swizzle character.  When processing swizzles, the first
    * character in the string is indexed in the previous table.  Each character
    * in the string is indexed in this table, and the value found there has the
    * value form the first table subtracted.  The result must be on the range
    * [0,3].
    *
    * For example, the string "wzyx" will get X from the first table.  Each of
    * the charcaters will get X+3, X+2, X+1, and X+0 from this table.  After
    * subtraction, the swizzle values are { 3, 2, 1, 0 }.
    *
    * The string "wzrg" will get X from the first table.  Each of the characters
    * will get X+3, X+2, R+0, and R+1 from this table.  After subtraction, the
    * swizzle values are { 3, 2, 4, 5 }.  Since 4 and 5 are outside the range
    * [0,3], the error is detected.
    */
   static const unsigned char idx_map[26] = {
   /* a    b    c    d    e    f    g    h    i    j    k    l    m */
      R+3, R+2, 0,   0,   0,   0,   R+1, 0,   0,   0,   0,   0,   0,
   /* n    o    p    q    r    s    t    u    v    w    x    y    z */
      0,   0,   S+2, S+3, R+0, S+0, S+1, 0,   0,   X+3, X+0, X+1, X+2
   };

   int swiz_idx[4] = { 0, 0, 0, 0 };
   unsigned i;


   /* Validate the first character in the swizzle string and look up the base
    * index value as described above.
    */
   if ((str[0] < 'a') || (str[0] > 'z'))
      return NULL;

   const unsigned base = base_idx[str[0] - 'a'];


   for (i = 0; (i < 4) && (str[i] != '\0'); i++) {
      /* Validate the next character, and, as described above, convert it to a
       * swizzle index.
       */
      if ((str[i] < 'a') || (str[i] > 'z'))
	 return NULL;

      swiz_idx[i] = idx_map[str[i] - 'a'] - base;
      if ((swiz_idx[i] < 0) || (swiz_idx[i] >= (int) vector_length))
	 return NULL;
   }

   if (str[i] != '\0')
	 return NULL;

   return new ir_swizzle(val, swiz_idx[0], swiz_idx[1], swiz_idx[2],
                         swiz_idx[3], i);
}

#undef X
#undef R
#undef S
#undef I


ir_variable::ir_variable(const struct glsl_type *type, const char *name)
   : ir_instruction(), read_only(false), centroid(false), invariant(false),
     mode(ir_var_auto), interpolation(ir_var_smooth)
{
   this->type = type;
   this->name = name;
}


ir_function_signature::ir_function_signature(const glsl_type *return_type)
   : ir_instruction(), return_type(return_type), definition(NULL)
{
   /* empty */
}


ir_function::ir_function(const char *name)
   : ir_instruction(), name(name)
{
   /* empty */
}


ir_call *
ir_call::get_error_instruction()
{
   ir_call *call = new ir_call;

   call->type = glsl_type::error_type;
   return call;
}