slang_codegen.c

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

      scope->outer_scope = fun->parameters;

      /* create local var 't' */
      var = slang_variable_scope_grow(scope);
      var->a_name = slang_atom_pool_atom(A->atoms, "t");
      var->type = fun->header.type;

      /* declare t */
      {
         slang_operation *decl;

         decl = &fun->body->children[0];
         decl->type = SLANG_OPER_VARIABLE_DECL;
         decl->locals = _slang_variable_scope_new(scope);
         decl->a_id = var->a_name;
      }

      /* assign params to fields of t */
      for (i = 0; i < numFields; i++) {
         slang_operation *assign = &fun->body->children[1 + i];

         assign->type = SLANG_OPER_ASSIGN;
         assign->locals = _slang_variable_scope_new(scope);
         assign->num_children = 2;
         assign->children = slang_operation_new(2);
         
         {
            slang_operation *lhs = &assign->children[0];

            lhs->type = SLANG_OPER_FIELD;
            lhs->locals = _slang_variable_scope_new(scope);
            lhs->num_children = 1;
            lhs->children = slang_operation_new(1);
            lhs->a_id = str->fields->variables[i]->a_name;

            lhs->children[0].type = SLANG_OPER_IDENTIFIER;
            lhs->children[0].a_id = var->a_name;
            lhs->children[0].locals = _slang_variable_scope_new(scope);

#if 0
            lhs->children[1].num_children = 1;
            lhs->children[1].children = slang_operation_new(1);
            lhs->children[1].children[0].type = SLANG_OPER_IDENTIFIER;
            lhs->children[1].children[0].a_id = str->fields->variables[i]->a_name;
            lhs->children[1].children->locals = _slang_variable_scope_new(scope);
#endif
         }

         {
            slang_operation *rhs = &assign->children[1];

            rhs->type = SLANG_OPER_IDENTIFIER;
            rhs->locals = _slang_variable_scope_new(scope);
            rhs->a_id = str->fields->variables[i]->a_name;
         }         
      }

      /* return t; */
      {
         slang_operation *ret = &fun->body->children[numFields + 1];

         ret->type = SLANG_OPER_RETURN;
         ret->locals = _slang_variable_scope_new(scope);
         ret->num_children = 1;
         ret->children = slang_operation_new(1);
         ret->children[0].type = SLANG_OPER_IDENTIFIER;
         ret->children[0].a_id = var->a_name;
         ret->children[0].locals = _slang_variable_scope_new(scope);

      }
   }
   /*
   slang_print_function(fun, 1);
   */
   return fun;
}


/**
 * Find/create a function (constructor) for the given structure name.
 */
static slang_function *
_slang_locate_struct_constructor(slang_assemble_ctx *A, const char *name)
{
   unsigned int i;
   for (i = 0; i < A->space.structs->num_structs; i++) {
      slang_struct *str = &A->space.structs->structs[i];
      if (strcmp(name, (const char *) str->a_name) == 0) {
         /* found a structure type that matches the function name */
         if (!str->constructor) {
            /* create the constructor function now */
            str->constructor = _slang_make_constructor(A, str);
         }
         return str->constructor;
      }
   }
   return NULL;
}



static GLboolean
_slang_is_vec_mat_type(const char *name)
{
   static const char *vecmat_types[] = {
      "float", "int", "bool",
      "vec2", "vec3", "vec4",
      "ivec2", "ivec3", "ivec4",
      "bvec2", "bvec3", "bvec4",
      "mat2", "mat3", "mat4",
      "mat2x3", "mat2x4", "mat3x2", "mat3x4", "mat4x2", "mat4x3",
      NULL
   };
   int i;
   for (i = 0; vecmat_types[i]; i++)
      if (_mesa_strcmp(name, vecmat_types[i]) == 0)
         return GL_TRUE;
   return GL_FALSE;
}


/**
 * Assemble a function call, given a particular function name.
 * \param name  the function's name (operators like '*' are possible).
 */
static slang_ir_node *
_slang_gen_function_call_name(slang_assemble_ctx *A, const char *name,
                              slang_operation *oper, slang_operation *dest)
{
   slang_operation *params = oper->children;
   const GLuint param_count = oper->num_children;
   slang_atom atom;
   slang_function *fun;
   GLboolean error;
   slang_ir_node *n;

   atom = slang_atom_pool_atom(A->atoms, name);
   if (atom == SLANG_ATOM_NULL)
      return NULL;

   /*
    * First, try to find function by name and exact argument type matching.
    */
   fun = _slang_locate_function(A->space.funcs, atom, params, param_count,
				&A->space, A->atoms, A->log, &error);

   if (error) {
      slang_info_log_error(A->log,
                           "Function '%s' not found (check argument types)",
                           name);
      return NULL;
   }

   if (!fun) {
      /* Next, try locating a constructor function for a user-defined type */
      fun = _slang_locate_struct_constructor(A, name);
   }

   /*
    * At this point, some heuristics are used to try to find a function
    * that matches the calling signature by means of casting or "unrolling"
    * of constructors.
    */

   if (!fun && _slang_is_vec_mat_type(name)) {
      /* Next, if this call looks like a vec() or mat() constructor call,
       * try "unwinding" the args to satisfy a constructor.
       */
      fun = _slang_find_function_by_max_argc(A->space.funcs, name);
      if (fun) {
         if (!_slang_adapt_call(oper, fun, &A->space, A->atoms, A->log)) {
            slang_info_log_error(A->log,
                                 "Function '%s' not found (check argument types)",
                                 name);
            return NULL;
         }
      }
   }

   if (!fun && _slang_is_vec_mat_type(name)) {
      /* Next, try casting args to the types of the formal parameters */
      int numArgs = oper->num_children;
      fun = _slang_find_function_by_argc(A->space.funcs, name, numArgs);
      if (!fun || !_slang_cast_func_params(oper, fun, &A->space, A->atoms, A->log)) {
         slang_info_log_error(A->log,
                              "Function '%s' not found (check argument types)",
                              name);
         return NULL;
      }
      assert(fun);
   }

   if (!fun) {
      slang_info_log_error(A->log,
                           "Function '%s' not found (check argument types)",
                           name);
      return NULL;
   }

   n = _slang_gen_function_call(A, fun, oper, dest);

   if (n && !n->Store && !dest
       && fun->header.type.specifier.type != SLANG_SPEC_VOID) {
      /* setup n->Store for the result of the function call */
      GLint size = _slang_sizeof_type_specifier(&fun->header.type.specifier);
      n->Store = _slang_new_ir_storage(PROGRAM_TEMPORARY, -1, size);
      /*printf("Alloc storage for function result, size %d \n", size);*/
   }

   return n;
}


static GLboolean
_slang_is_constant_cond(const slang_operation *oper, GLboolean *value)
{
   if (oper->type == SLANG_OPER_LITERAL_FLOAT ||
       oper->type == SLANG_OPER_LITERAL_INT ||
       oper->type == SLANG_OPER_LITERAL_BOOL) {
      if (oper->literal[0])
         *value = GL_TRUE;
      else
         *value = GL_FALSE;
      return GL_TRUE;
   }
   else if (oper->type == SLANG_OPER_EXPRESSION &&
            oper->num_children == 1) {
      return _slang_is_constant_cond(&oper->children[0], value);
   }
   return GL_FALSE;
}


/**
 * Test if an operation is a scalar or boolean.
 */
static GLboolean
_slang_is_scalar_or_boolean(slang_assemble_ctx *A, slang_operation *oper)
{
   slang_typeinfo type;
   GLint size;

   slang_typeinfo_construct(&type);
   _slang_typeof_operation(A, oper, &type);
   size = _slang_sizeof_type_specifier(&type.spec);
   slang_typeinfo_destruct(&type);
   return size == 1;
}


/**
 * Test if an operation is boolean.
 */
static GLboolean
_slang_is_boolean(slang_assemble_ctx *A, slang_operation *oper)
{
   slang_typeinfo type;
   GLboolean isBool;

   slang_typeinfo_construct(&type);
   _slang_typeof_operation(A, oper, &type);
   isBool = (type.spec.type == SLANG_SPEC_BOOL);
   slang_typeinfo_destruct(&type);
   return isBool;
}


/**
 * Generate loop code using high-level IR_LOOP instruction
 */
static slang_ir_node *
_slang_gen_while(slang_assemble_ctx * A, const slang_operation *oper)
{
   /*
    * LOOP:
    *    BREAK if !expr (child[0])
    *    body code (child[1])
    */
   slang_ir_node *prevLoop, *loop, *breakIf, *body;
   GLboolean isConst, constTrue;

   /* type-check expression */
   if (!_slang_is_boolean(A, &oper->children[0])) {
      slang_info_log_error(A->log, "scalar/boolean expression expected for 'while'");
      return NULL;
   }

   /* Check if loop condition is a constant */
   isConst = _slang_is_constant_cond(&oper->children[0], &constTrue);

   if (isConst && !constTrue) {
      /* loop is never executed! */
      return new_node0(IR_NOP);
   }

   loop = new_loop(NULL);

   /* save old, push new loop */
   prevLoop = A->CurLoop;
   A->CurLoop = loop;

   if (isConst && constTrue) {
      /* while(nonzero constant), no conditional break */
      breakIf = NULL;
   }
   else {
      slang_ir_node *cond
         = new_cond(new_not(_slang_gen_operation(A, &oper->children[0])));
      breakIf = new_break_if_true(A->CurLoop, cond);
   }
   body = _slang_gen_operation(A, &oper->children[1]);
   loop->Children[0] = new_seq(breakIf, body);

   /* Do infinite loop detection */
   /* loop->List is head of linked list of break/continue nodes */
   if (!loop->List && isConst && constTrue) {
      /* infinite loop detected */
      A->CurLoop = prevLoop; /* clean-up */
      slang_info_log_error(A->log, "Infinite loop detected!");
      return NULL;
   }

   /* pop loop, restore prev */
   A->CurLoop = prevLoop;

   return loop;
}


/**
 * Generate IR tree for a do-while loop using high-level LOOP, IF instructions.
 */
static slang_ir_node *
_slang_gen_do(slang_assemble_ctx * A, const slang_operation *oper)
{
   /*
    * LOOP:
    *    body code (child[0])
    *    tail code:
    *       BREAK if !expr (child[1])
    */
   slang_ir_node *prevLoop, *loop;
   GLboolean isConst, constTrue;

   /* type-check expression */
   if (!_slang_is_boolean(A, &oper->children[1])) {
      slang_info_log_error(A->log, "scalar/boolean expression expected for 'do/while'");
      return NULL;
   }

   loop = new_loop(NULL);

   /* save old, push new loop */
   prevLoop = A->CurLoop;
   A->CurLoop = loop;

   /* loop body: */
   loop->Children[0] = _slang_gen_operation(A, &oper->children[0]);

   /* Check if loop condition is a constant */
   isConst = _slang_is_constant_cond(&oper->children[1], &constTrue);
   if (isConst && constTrue) {
      /* do { } while(1)   ==> no conditional break */
      loop->Children[1] = NULL; /* no tail code */
   }
   else {
      slang_ir_node *cond
         = new_cond(new_not(_slang_gen_operation(A, &oper->children[1])));
      loop->Children[1] = new_break_if_true(A->CurLoop, cond);
   }

   /* XXX we should do infinite loop detection, as above */

   /* pop loop, restore prev */
   A->CurLoop = prevLoop;

   return loop;
}


/**
 * Generate for-loop using high-level IR_LOOP instruction.
 */
static slang_ir_node *
_slang_gen_for(slang_assemble_ctx * A, const slang_operation *oper)
{
   /*
    * init code (child[0])
    * LOOP:
    *    BREAK if !expr (child[1])
    *    body code (child[3])
    *    tail code:
    *       incr code (child[2])   // XXX continue here
    */
   slang_ir_node *prevLoop, *loop, *cond, *breakIf, *body, *init, *incr;

   init = _slang_gen_operation(A, &oper->children[0]);
   loop = new_loop(NULL);

   /* save old, push new loop */
   prevLoop = A->CurLoop;
   A->CurLoop = loop;

   cond = new_cond(new_not(_slang_gen_operation(A, &oper->children[1])));
   breakIf = new_break_if_true(A->CurLoop, cond);
   body = _slang_gen_operation(A, &oper->children[3]);
   incr = _slang_gen_operation(A, &oper->children[2]);

   loop->Children[0] = new_seq(breakIf, body);
   loop->Children[1] = incr;  /* tail code */

   /* pop loop, restore prev */
   A->CurLoop = prevLoop;

   return new_seq(init, loop);
}


static slang_ir_node *
_slang_gen_continue(slang_assemble_ctx * A, const slang_operation *oper)
{
   slang_ir_node *n, *loopNode;
   assert(oper->type == SLANG_OPER_CONTINUE);
   loopNode = A->CurLoop;
   assert(loopNode);
   assert(loopNode->Opcode == IR_LOOP);
   n = new_node0(IR_CONT);
   if (n) {
      n->Parent = loopNode;
      /* insert this node at head of linked list */
      n->List = loopNode->List;
      loopNode->List = n;
   }
   return n;
}


/**
 * Determine if the given operation is of a specific type.
 */
static GLboolean
is_operation_type(const slang_operation *oper, slang_operation_type type)
{
   if (oper->type == type)
      return GL_TRUE;
   else if ((oper->type == SLANG_OPER_BLOCK_NEW_SCOPE ||
             oper->type == SLANG_OPER_BLOCK_NO_NEW_SCOPE) &&
            oper->num_children == 1)
      return is_operation_type(&oper->children[0], type);
   else
      return GL_FALSE;
}


/**
 * Generate IR tree for an if/then/else conditional using high-level