semantics.c

gcc-2.95.3 Linux下最常用的C编译器

	expand_computed_goto (destination);
    }
}

/* Begin a try-block.  Returns a newly-created TRY_BLOCK if
   appropriate.  */

tree
begin_try_block ()
{
  if (processing_template_decl)
    {
      tree r = build_min_nt (TRY_BLOCK, NULL_TREE,
			     NULL_TREE);
      add_tree (r);
      return r;
    }
  else
    {
      emit_line_note (input_filename, lineno);
      expand_start_try_stmts ();
      return NULL_TREE;
    }
}

/* Finish a try-block, which may be given by TRY_BLOCK.  */

void
finish_try_block (try_block)
     tree try_block;
{
  if (processing_template_decl)
    RECHAIN_STMTS_FROM_LAST (try_block, TRY_STMTS (try_block));
  else
    {
      expand_start_all_catch ();  
    }
}

/* Finish a handler-sequence for a try-block, which may be given by
   TRY_BLOCK.  */

void
finish_handler_sequence (try_block)
     tree try_block;
{
  if (processing_template_decl)
    RECHAIN_STMTS_FROM_CHAIN (try_block, TRY_HANDLERS (try_block));
  else
    {
      expand_end_all_catch ();
    }
}

/* Begin a handler.  Returns a HANDLER if appropriate.  */

tree
begin_handler ()
{
  tree r;

  if (processing_template_decl)
    {
      r = build_min_nt (HANDLER, NULL_TREE, NULL_TREE);
      add_tree (r);
    }
  else
    r = NULL_TREE;

  do_pushlevel ();

  return r;
}

/* Finish the handler-parameters for a handler, which may be given by
   HANDLER.  */

void
finish_handler_parms (handler)
     tree handler;
{
  if (processing_template_decl)
    RECHAIN_STMTS_FROM_CHAIN (handler, HANDLER_PARMS (handler));
}

/* Finish a handler, which may be given by HANDLER.  */

void
finish_handler (handler)
     tree handler;
{
  if (processing_template_decl)
    RECHAIN_STMTS_FROM_CHAIN (handler, HANDLER_BODY (handler));
  else
    expand_end_catch_block ();

  do_poplevel ();
}

/* Begin a compound-statement.  If HAS_NO_SCOPE is non-zero, the
   compound-statement does not define a scope.  Returns a new
   COMPOUND_STMT if appropriate.  */

tree
begin_compound_stmt (has_no_scope)
     int has_no_scope;
{
  tree r; 

  if (processing_template_decl)
    {
      r = build_min_nt (COMPOUND_STMT, NULL_TREE);
      add_tree (r);
      if (has_no_scope)
	COMPOUND_STMT_NO_SCOPE (r) = 1;
    }
  else
    r = NULL_TREE;

  if (!has_no_scope)
    do_pushlevel ();

  return r;
}


/* Finish a compound-statement, which may be given by COMPOUND_STMT.
   If HAS_NO_SCOPE is non-zero, the compound statement does not define
   a scope.  */

tree
finish_compound_stmt (has_no_scope, compound_stmt)
     int has_no_scope;
     tree compound_stmt;
{
  tree r;

  if (!has_no_scope)
    r = do_poplevel ();
  else
    r = NULL_TREE;

  if (processing_template_decl)
    RECHAIN_STMTS_FROM_CHAIN (compound_stmt, 
			      COMPOUND_BODY (compound_stmt));

  finish_stmt ();

  return r;
}

/* Finish an asm-statement, whose components are a CV_QUALIFIER, a
   STRING, some OUTPUT_OPERANDS, some INPUT_OPERANDS, and some
   CLOBBERS.  */

void
finish_asm_stmt (cv_qualifier, string, output_operands,
		      input_operands, clobbers)
     tree cv_qualifier;
     tree string;
     tree output_operands;
     tree input_operands;
     tree clobbers;
{
  if (TREE_CHAIN (string))
    string = combine_strings (string);

  if (processing_template_decl)
    {
      tree r = build_min_nt (ASM_STMT, cv_qualifier, string,
			     output_operands, input_operands,
			     clobbers);
      add_tree (r);
    }
  else
    {
      emit_line_note (input_filename, lineno);
      if (output_operands != NULL_TREE || input_operands != NULL_TREE
	    || clobbers != NULL_TREE)
	{
	  tree t;

	  if (cv_qualifier != NULL_TREE
	      && cv_qualifier != ridpointers[(int) RID_VOLATILE])
	    cp_warning ("%s qualifier ignored on asm",
			IDENTIFIER_POINTER (cv_qualifier));

	  for (t = input_operands; t; t = TREE_CHAIN (t))
	    TREE_VALUE (t) = decay_conversion (TREE_VALUE (t));

	  c_expand_asm_operands (string, output_operands,
				 input_operands, 
				 clobbers,
				 cv_qualifier 
				 == ridpointers[(int) RID_VOLATILE],
				 input_filename, lineno);
	}
      else
	{
	  /* Don't warn about redundant specification of 'volatile' here.  */
	  if (cv_qualifier != NULL_TREE
	      && cv_qualifier != ridpointers[(int) RID_VOLATILE])
	    cp_warning ("%s qualifier ignored on asm",
			IDENTIFIER_POINTER (cv_qualifier));
	  expand_asm (string);
	}
      
      finish_stmt ();
    }
}

/* Finish a parenthesized expression EXPR.  */

tree
finish_parenthesized_expr (expr)
     tree expr;
{
  if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (expr))))
    /* This inhibits warnings in truthvalue_conversion.  */
    C_SET_EXP_ORIGINAL_CODE (expr, ERROR_MARK); 

  return expr;
}

/* Begin a statement-expression.  The value returned must be passed to
   finish_stmt_expr.  */

tree 
begin_stmt_expr ()
{
  keep_next_level ();
  /* If we're processing_template_decl, then the upcoming compound
     statement will be chained onto the tree structure, starting at
     last_tree.  We return last_tree so that we can later unhook the
     compound statement.  */
  return processing_template_decl ? last_tree : expand_start_stmt_expr(); 
}

/* Finish a statement-expression.  RTL_EXPR should be the value
   returned by the previous begin_stmt_expr; EXPR is the
   statement-expression.  Returns an expression representing the
   statement-expression.  */

tree 
finish_stmt_expr (rtl_expr, expr)
     tree rtl_expr;
     tree expr;
{
  tree result;

  if (!processing_template_decl)
    {
      rtl_expr = expand_end_stmt_expr (rtl_expr);
      /* The statements have side effects, so the group does.  */
      TREE_SIDE_EFFECTS (rtl_expr) = 1;
    }

  if (TREE_CODE (expr) == BLOCK)
    {
      /* Make a BIND_EXPR for the BLOCK already made.  */
      if (processing_template_decl)
	result = build_min_nt (BIND_EXPR, NULL_TREE, last_tree,
			       NULL_TREE);
      else
	result = build (BIND_EXPR, TREE_TYPE (rtl_expr),
			NULL_TREE, rtl_expr, expr);
      
      /* Remove the block from the tree at this point.
	 It gets put back at the proper place
	 when the BIND_EXPR is expanded.  */
      delete_block (expr);
    }
  else
    result = expr;

  if (processing_template_decl)
    {
      /* Remove the compound statement from the tree structure; it is
	 now saved in the BIND_EXPR.  */
      last_tree = rtl_expr;
      TREE_CHAIN (last_tree) = NULL_TREE;
    }
  
  return result;
}

/* Finish a call to FN with ARGS.  Returns a representation of the
   call.  */

tree 
finish_call_expr (fn, args, koenig)
     tree fn;
     tree args;
     int koenig;
{
  tree result;

  if (koenig)
    {
      if (TREE_CODE (fn) == BIT_NOT_EXPR)
	fn = build_x_unary_op (BIT_NOT_EXPR, TREE_OPERAND (fn, 0));
      else if (TREE_CODE (fn) != TEMPLATE_ID_EXPR)
	fn = do_identifier (fn, 2, args);
    }
  result = build_x_function_call (fn, args, current_class_ref);

  if (TREE_CODE (result) == CALL_EXPR
      && (! TREE_TYPE (result)
          || TREE_CODE (TREE_TYPE (result)) != VOID_TYPE))
    result = require_complete_type (result);

  return result;
}

/* Finish a call to a postfix increment or decrement or EXPR.  (Which
   is indicated by CODE, which should be POSTINCREMENT_EXPR or
   POSTDECREMENT_EXPR.)  */

tree 
finish_increment_expr (expr, code)
     tree expr;
     enum tree_code code;
{
  /* If we get an OFFSET_REF, turn it into what it really means (e.g.,
     a COMPONENT_REF).  This way if we've got, say, a reference to a
     static member that's being operated on, we don't end up trying to
     find a member operator for the class it's in.  */

  if (TREE_CODE (expr) == OFFSET_REF)
    expr = resolve_offset_ref (expr);
  return build_x_unary_op (code, expr);  
}

/* Finish a use of `this'.  Returns an expression for `this'.  */

tree 
finish_this_expr ()
{
  tree result;

  if (current_class_ptr)
    {
#ifdef WARNING_ABOUT_CCD
      TREE_USED (current_class_ptr) = 1;
#endif
      result = current_class_ptr;
    }
  else if (current_function_decl
	   && DECL_STATIC_FUNCTION_P (current_function_decl))
    {
      error ("`this' is unavailable for static member functions");
      result = error_mark_node;
    }
  else
    {
      if (current_function_decl)
	error ("invalid use of `this' in non-member function");
      else
	error ("invalid use of `this' at top level");
      result = error_mark_node;
    }

  return result;
}

/* Finish a member function call using OBJECT and ARGS as arguments to
   FN.  Returns an expression for the call.  */

tree 
finish_object_call_expr (fn, object, args)
     tree fn;
     tree object;
     tree args;
{
#if 0
  /* This is a future direction of this code, but because
     build_x_function_call cannot always undo what is done in
     build_component_ref entirely yet, we cannot do this.  */

  tree real_fn = build_component_ref (object, fn, NULL_TREE, 1);
  return finish_call_expr (real_fn, args);
#else
  if (TREE_CODE (fn) == TYPE_DECL)
    {
      if (processing_template_decl)
	/* This can happen on code like:

	   class X;
	   template <class T> void f(T t) {
	     t.X();
	   }  

	   We just grab the underlying IDENTIFIER.  */
	fn = DECL_NAME (fn);
      else
	{
	  cp_error ("calling type `%T' like a method", fn);
	  return error_mark_node;
	}
    }

  return build_method_call (object, fn, args, NULL_TREE, LOOKUP_NORMAL);
#endif
}

/* Finish a qualified member function call using OBJECT and ARGS as
   arguments to FN.  Returns an expressino for the call.  */

tree 
finish_qualified_object_call_expr (fn, object, args)
     tree fn;
     tree object;
     tree args;
{
  if (IS_SIGNATURE (TREE_OPERAND (fn, 0)))
    {
      warning ("signature name in scope resolution ignored");
      return finish_object_call_expr (TREE_OPERAND (fn, 1), object, args);
    }
  else
    return build_scoped_method_call (object, TREE_OPERAND (fn, 0),
				     TREE_OPERAND (fn, 1), args);
}

/* Finish a pseudo-destructor call expression of OBJECT, with SCOPE
   being the scope, if any, of DESTRUCTOR.  Returns an expression for
   the call.  */

tree 
finish_pseudo_destructor_call_expr (object, scope, destructor)
     tree object;
     tree scope;
     tree destructor;
{
  if (scope && scope != destructor)
    cp_error ("destructor specifier `%T::~%T()' must have matching names", 
	      scope, destructor);

  if ((scope == NULL_TREE || IDENTIFIER_GLOBAL_VALUE (destructor))
      && (TREE_CODE (TREE_TYPE (object)) !=
	  TREE_CODE (TREE_TYPE (IDENTIFIER_GLOBAL_VALUE (destructor)))))
    cp_error ("`%E' is not of type `%T'", object, destructor);

  return cp_convert (void_type_node, object);
}

/* Finish a call to a globally qualified member function FN using
   ARGS.  Returns an expression for the call.  */

tree 
finish_qualified_call_expr (fn, args)
     tree fn;
     tree args;
{
  if (processing_template_decl)
    return build_min_nt (CALL_EXPR, copy_to_permanent (fn), args,
			 NULL_TREE);
  else
    return build_member_call (TREE_OPERAND (fn, 0),
			      TREE_OPERAND (fn, 1),
			      args);
}

/* Finish an expression taking the address of LABEL.  Returns an
   expression for the address.  */

tree 
finish_label_address_expr (label)
     tree label;
{
  tree result;

  label = lookup_label (label);
  if (label == NULL_TREE)
    result = null_pointer_node;
  else
    {
      TREE_USED (label) = 1;
      result = build1 (ADDR_EXPR, ptr_type_node, label);
      TREE_CONSTANT (result) = 1;
    }

  return result;
}

/* Finish an expression of the form CODE EXPR.  */

tree
finish_unary_op_expr (code, expr)
     enum tree_code code;
     tree expr;
{
  tree result = build_x_unary_op (code, expr);
  if (code == NEGATE_EXPR && TREE_CODE (expr) == INTEGER_CST)
    TREE_NEGATED_INT (result) = 1;
  overflow_warning (result);
  return result;
}

/* Finish an id-expression.  */

tree
finish_id_expr (expr)
     tree expr;
{
  if (TREE_CODE (expr) == IDENTIFIER_NODE)
    expr = do_identifier (expr, 1, NULL_TREE);

  return expr;
}

/* Begin a new-placement.  */

int
begin_new_placement ()
{
  /* The arguments to a placement new might be passed to a
     deallocation function, in the event that the allocation throws an
     exception.  Since we don't expand exception handlers until the
     end of a function, we must make sure the arguments stay around
     that long.  */
  return suspend_momentary ();
}

/* Finish a new-placement.  The ARGS are the placement arguments.  The
   COOKIE is the value returned by the previous call to
   begin_new_placement.  */

tree
finish_new_placement (args, cookie)
     tree args;
     int cookie;
{
  resume_momentary (cookie);
  return args;
}

/* Begin a function defniition declared with DECL_SPECS and
   DECLARATOR.  Returns non-zero if the function-declaration is
   legal.  */

int
begin_function_definition (decl_specs, declarator)
     tree decl_specs;
     tree declarator;
{
  tree specs;
  tree attrs;
  split_specs_attrs (decl_specs, &specs, &attrs);
  if (!start_function (specs, declarator, attrs, 0))
    return 0;
  
  reinit_parse_for_function ();
  /* The things we're about to see are not directly qualified by any
     template headers we've seen thus far.  */
  reset_specialization ();

  return 1;
}

/* Begin a constructor declarator of the form `SCOPE::NAME'.  Returns
   a SCOPE_REF.  */