slang_codegen.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

   /* Replace the function call with the inlined block (or new CALL stmt) */
   slang_operation_destruct(oper);
   *oper = *inlined;
   _slang_free(inlined);

#if 0
   assert(inlined->locals);
   printf("*** Inlined code for call to %s:\n",
          (char*) fun->header.a_name);
   slang_print_tree(oper, 10);
   printf("\n");
#endif

   n = _slang_gen_operation(A, oper);

   /*_slang_label_delete(A->curFuncEndLabel);*/
   A->curFuncEndLabel = prevFuncEndLabel;

   return n;
}


static slang_asm_info *
slang_find_asm_info(const char *name)
{
   GLuint i;
   for (i = 0; AsmInfo[i].Name; i++) {
      if (_mesa_strcmp(AsmInfo[i].Name, name) == 0) {
         return AsmInfo + i;
      }
   }
   return NULL;
}


/**
 * Return the default swizzle mask for accessing a variable of the
 * given size (in floats).  If size = 1, comp is used to identify
 * which component [0..3] of the register holds the variable.
 */
static GLuint
_slang_var_swizzle(GLint size, GLint comp)
{
   switch (size) {
   case 1:
      return MAKE_SWIZZLE4(comp, comp, comp, comp);
   case 2:
      return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_NIL, SWIZZLE_NIL);
   case 3:
      return MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_NIL);
   default:
      return SWIZZLE_XYZW;
   }
}


/**
 * Some write-masked assignments are simple, but others are hard.
 * Simple example:
 *    vec3 v;
 *    v.xy = vec2(a, b);
 * Hard example:
 *    vec3 v;
 *    v.zy = vec2(a, b);
 * this gets transformed/swizzled into:
 *    v.zy = vec2(a, b).*yx*         (* = don't care)
 * This function helps to determine simple vs. non-simple.
 */
static GLboolean
_slang_simple_writemask(GLuint writemask, GLuint swizzle)
{
   switch (writemask) {
   case WRITEMASK_X:
      return GET_SWZ(swizzle, 0) == SWIZZLE_X;
   case WRITEMASK_Y:
      return GET_SWZ(swizzle, 1) == SWIZZLE_Y;
   case WRITEMASK_Z:
      return GET_SWZ(swizzle, 2) == SWIZZLE_Z;
   case WRITEMASK_W:
      return GET_SWZ(swizzle, 3) == SWIZZLE_W;
   case WRITEMASK_XY:
      return (GET_SWZ(swizzle, 0) == SWIZZLE_X)
         && (GET_SWZ(swizzle, 1) == SWIZZLE_Y);
   case WRITEMASK_XYZ:
      return (GET_SWZ(swizzle, 0) == SWIZZLE_X)
         && (GET_SWZ(swizzle, 1) == SWIZZLE_Y)
         && (GET_SWZ(swizzle, 2) == SWIZZLE_Z);
   case WRITEMASK_XYZW:
      return swizzle == SWIZZLE_NOOP;
   default:
      return GL_FALSE;
   }
}


/**
 * Convert the given swizzle into a writemask.  In some cases this
 * is trivial, in other cases, we'll need to also swizzle the right
 * hand side to put components in the right places.
 * \param swizzle  the incoming swizzle
 * \param writemaskOut  returns the writemask
 * \param swizzleOut  swizzle to apply to the right-hand-side
 * \return GL_FALSE for simple writemasks, GL_TRUE for non-simple
 */
static GLboolean
swizzle_to_writemask(slang_assemble_ctx *A, GLuint swizzle,
                     GLuint *writemaskOut, GLuint *swizzleOut)
{
   GLuint mask = 0x0, newSwizzle[4];
   GLint i, size;

   /* make new dst writemask, compute size */
   for (i = 0; i < 4; i++) {
      const GLuint swz = GET_SWZ(swizzle, i);
      if (swz == SWIZZLE_NIL) {
         /* end */
         break;
      }
      assert(swz >= 0 && swz <= 3);

      if (swizzle != SWIZZLE_XXXX &&
          swizzle != SWIZZLE_YYYY &&
          swizzle != SWIZZLE_ZZZZ &&
          swizzle != SWIZZLE_WWWW &&
          (mask & (1 << swz))) {
         /* a channel can't be specified twice (ex: ".xyyz") */
         slang_info_log_error(A->log, "Invalid writemask '%s'",
                              _mesa_swizzle_string(swizzle, 0, 0));
         return GL_FALSE;
      }

      mask |= (1 << swz);
   }
   assert(mask <= 0xf);
   size = i;  /* number of components in mask/swizzle */

   *writemaskOut = mask;

   /* make new src swizzle, by inversion */
   for (i = 0; i < 4; i++) {
      newSwizzle[i] = i; /*identity*/
   }
   for (i = 0; i < size; i++) {
      const GLuint swz = GET_SWZ(swizzle, i);
      newSwizzle[swz] = i;
   }
   *swizzleOut = MAKE_SWIZZLE4(newSwizzle[0],
                               newSwizzle[1],
                               newSwizzle[2],
                               newSwizzle[3]);

   if (_slang_simple_writemask(mask, *swizzleOut)) {
      if (size >= 1)
         assert(GET_SWZ(*swizzleOut, 0) == SWIZZLE_X);
      if (size >= 2)
         assert(GET_SWZ(*swizzleOut, 1) == SWIZZLE_Y);
      if (size >= 3)
         assert(GET_SWZ(*swizzleOut, 2) == SWIZZLE_Z);
      if (size >= 4)
         assert(GET_SWZ(*swizzleOut, 3) == SWIZZLE_W);
      return GL_TRUE;
   }
   else
      return GL_FALSE;
}


/**
 * Recursively traverse 'oper' to produce a swizzle mask in the event
 * of any vector subscripts and swizzle suffixes.
 * Ex:  for "vec4 v",  "v[2].x" resolves to v.z
 */
static GLuint
resolve_swizzle(const slang_operation *oper)
{
   if (oper->type == SLANG_OPER_FIELD) {
      /* writemask from .xyzw suffix */
      slang_swizzle swz;
      if (_slang_is_swizzle((char*) oper->a_id, 4, &swz)) {
         GLuint swizzle = MAKE_SWIZZLE4(swz.swizzle[0],
                                        swz.swizzle[1],
                                        swz.swizzle[2],
                                        swz.swizzle[3]);
         GLuint child_swizzle = resolve_swizzle(&oper->children[0]);
         GLuint s = _slang_swizzle_swizzle(child_swizzle, swizzle);
         return s;
      }
      else
         return SWIZZLE_XYZW;
   }
   else if (oper->type == SLANG_OPER_SUBSCRIPT &&
            oper->children[1].type == SLANG_OPER_LITERAL_INT) {
      /* writemask from [index] */
      GLuint child_swizzle = resolve_swizzle(&oper->children[0]);
      GLuint i = (GLuint) oper->children[1].literal[0];
      GLuint swizzle;
      GLuint s;
      switch (i) {
      case 0:
         swizzle = SWIZZLE_XXXX;
         break;
      case 1:
         swizzle = SWIZZLE_YYYY;
         break;
      case 2:
         swizzle = SWIZZLE_ZZZZ;
         break;
      case 3:
         swizzle = SWIZZLE_WWWW;
         break;
      default:
         swizzle = SWIZZLE_XYZW;
      }
      s = _slang_swizzle_swizzle(child_swizzle, swizzle);
      return s;
   }
   else {
      return SWIZZLE_XYZW;
   }
}


/**
 * As above, but produce a writemask.
 */
static GLuint
resolve_writemask(slang_assemble_ctx *A, const slang_operation *oper)
{
   GLuint swizzle = resolve_swizzle(oper);
   GLuint writemask, swizzleOut;
   swizzle_to_writemask(A, swizzle, &writemask, &swizzleOut);
   return writemask;
}


/**
 * Recursively descend through swizzle nodes to find the node's storage info.
 */
static slang_ir_storage *
get_store(const slang_ir_node *n)
{
   if (n->Opcode == IR_SWIZZLE) {
      return get_store(n->Children[0]);
   }
   return n->Store;
}



/**
 * Generate IR tree for an asm instruction/operation such as:
 *    __asm vec4_dot __retVal.x, v1, v2;
 */
static slang_ir_node *
_slang_gen_asm(slang_assemble_ctx *A, slang_operation *oper,
               slang_operation *dest)
{
   const slang_asm_info *info;
   slang_ir_node *kids[3], *n;
   GLuint j, firstOperand;

   assert(oper->type == SLANG_OPER_ASM);

   info = slang_find_asm_info((char *) oper->a_id);
   if (!info) {
      _mesa_problem(NULL, "undefined __asm function %s\n",
                    (char *) oper->a_id);
      assert(info);
   }
   assert(info->NumParams <= 3);

   if (info->NumParams == oper->num_children) {
      /* Storage for result is not specified.
       * Children[0], [1], [2] are the operands.
       */
      firstOperand = 0;
   }
   else {
      /* Storage for result (child[0]) is specified.
       * Children[1], [2], [3] are the operands.
       */
      firstOperand = 1;
   }

   /* assemble child(ren) */
   kids[0] = kids[1] = kids[2] = NULL;
   for (j = 0; j < info->NumParams; j++) {
      kids[j] = _slang_gen_operation(A, &oper->children[firstOperand + j]);
      if (!kids[j])
         return NULL;
   }

   n = new_node3(info->Opcode, kids[0], kids[1], kids[2]);

   if (firstOperand) {
      /* Setup n->Store to be a particular location.  Otherwise, storage
       * for the result (a temporary) will be allocated later.
       */
      GLuint writemask = WRITEMASK_XYZW;
      slang_operation *dest_oper;
      slang_ir_node *n0;

      dest_oper = &oper->children[0];

      writemask = resolve_writemask(A, dest_oper);

      n0 = _slang_gen_operation(A, dest_oper);
      if (!n0)
         return NULL;

      assert(!n->Store);
      n->Store = n0->Store;

      assert(n->Store->File != PROGRAM_UNDEFINED || n->Store->Parent);

      _slang_free(n0);
   }

   return n;
}


static void
print_funcs(struct slang_function_scope_ *scope, const char *name)
{
   GLuint i;
   for (i = 0; i < scope->num_functions; i++) {
      slang_function *f = &scope->functions[i];
      if (!name || strcmp(name, (char*) f->header.a_name) == 0)
          printf("  %s (%d args)\n", name, f->param_count);

   }
   if (scope->outer_scope)
      print_funcs(scope->outer_scope, name);
}


/**
 * Find a function of the given name, taking 'numArgs' arguments.
 * This is the function we'll try to call when there is no exact match
 * between function parameters and call arguments.
 *
 * XXX we should really create a list of candidate functions and try
 * all of them...
 */
static slang_function *
_slang_find_function_by_argc(slang_function_scope *scope,
                             const char *name, int numArgs)
{
   while (scope) {
      GLuint i;
      for (i = 0; i < scope->num_functions; i++) {
         slang_function *f = &scope->functions[i];
         if (strcmp(name, (char*) f->header.a_name) == 0) {
            int haveRetValue = _slang_function_has_return_value(f);
            if (numArgs == f->param_count - haveRetValue)
               return f;
         }
      }
      scope = scope->outer_scope;
   }

   return NULL;
}


static slang_function *
_slang_find_function_by_max_argc(slang_function_scope *scope,
                                 const char *name)
{
   slang_function *maxFunc = NULL;
   GLuint maxArgs = 0;

   while (scope) {
      GLuint i;
      for (i = 0; i < scope->num_functions; i++) {
         slang_function *f = &scope->functions[i];
         if (strcmp(name, (char*) f->header.a_name) == 0) {
            if (f->param_count > maxArgs) {
               maxArgs = f->param_count;
               maxFunc = f;
            }
         }
      }
      scope = scope->outer_scope;
   }

   return maxFunc;
}


/**
 * Generate a new slang_function which is a constructor for a user-defined
 * struct type.
 */
static slang_function *
_slang_make_constructor(slang_assemble_ctx *A, slang_struct *str)
{
   const GLint numFields = str->fields->num_variables;

   slang_function *fun = (slang_function *) _mesa_malloc(sizeof(slang_function));
   if (!fun)
      return NULL;

   slang_function_construct(fun);

   /* function header (name, return type) */
   fun->kind = SLANG_FUNC_CONSTRUCTOR;
   fun->header.a_name = str->a_name;
   fun->header.type.qualifier = SLANG_QUAL_NONE;
   fun->header.type.specifier.type = SLANG_SPEC_STRUCT;
   fun->header.type.specifier._struct = str;

   /* function parameters (= struct's fields) */
   {
      GLint i;
      for (i = 0; i < numFields; i++) {
         /*
         printf("Field %d: %s\n", i, (char*) str->fields->variables[i]->a_name);
         */
         slang_variable *p = slang_variable_scope_grow(fun->parameters);
         *p = *str->fields->variables[i]; /* copy the type */
         p->type.qualifier = SLANG_QUAL_CONST;
      }
      fun->param_count = fun->parameters->num_variables;
   }

   /* Add __retVal to params */
   {
      slang_variable *p = slang_variable_scope_grow(fun->parameters);
      slang_atom a_retVal = slang_atom_pool_atom(A->atoms, "__retVal");
      assert(a_retVal);
      p->a_name = a_retVal;
      p->type = fun->header.type;
      p->type.qualifier = SLANG_QUAL_OUT;
      fun->param_count++;
   }

   /* function body is:
    *    block:
    *       declare T;
    *       T.f1 = p1;
    *       T.f2 = p2;
    *       ...
    *       T.fn = pn;
    *       return T;
    */
   {
      slang_variable_scope *scope;
      slang_variable *var;
      GLint i;

      fun->body = slang_operation_new(1);
      fun->body->type = SLANG_OPER_BLOCK_NEW_SCOPE;
      fun->body->num_children = numFields + 2;
      fun->body->children = slang_operation_new(numFields + 2);

      scope = fun->body->locals;