7cff0b1b79
* sem_warn.adb: Remove stuff for conditionals, we are not going to do this after all. * sem_warn.ads: Remove stuff for conditionals, we are not going to do this after all. Add 2001 to copyright notice From-SVN: r47677
129 lines
7.1 KiB
Ada
129 lines
7.1 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S E M _ W A R N --
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-- --
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-- S p e c --
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-- --
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-- $Revision$
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-- --
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-- Copyright (C) 1999-2001 Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
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-- --
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------------------------------------------------------------------------------
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-- This package contains the routines used to deal with issuing warnings
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-- about uses of uninitialized variables and unused with's. It also has
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-- some unrelated routines related to the generation of warnings.
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with Types; use Types;
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package Sem_Warn is
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------------------------------------------
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-- Routines to Handle Unused References --
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------------------------------------------
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procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty);
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-- Called at the end of processing a declarative region. The entity E
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-- is the entity for the scope. All entities declared in the region,
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-- as indicated by First_Entity and the entity chain, are checked to
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-- see if they are variables for which warnings need to be posted for
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-- either no assignments, or a use before an assignment or no references
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-- at all. The Anod node is present for the case of an accept statement,
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-- and references the accept statement. This is used to place the warning
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-- messages in the right place.
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procedure Check_Unset_Reference (N : Node_Id);
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-- N is the node for an expression which occurs in a reference position,
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-- e.g. as the right side of an assignment. This procedure checks to see
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-- if the node is a reference to a variable entity where the entity has
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-- Not_Assigned set. If so, the Unset_Reference field is set if it is not
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-- the first occurrence. No warning is posted, instead warnings will be
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-- posted later by Check_References. The reason we do things that
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-- way is that if there are no assignments anywhere, we prefer to flag
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-- the entity, rather than a reference to it. Note that for the purposes
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-- of this routine, a type conversion or qualified expression whose
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-- expression is an entity is also processed. The reason that we do not
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-- process these at the point of occurrence is that both these constructs
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-- can occur in non-reference positions (e.g. as out parameters).
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procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit);
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-- This routine performs two kinds of checks. It checks that all with'ed
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-- units are referenced, and that at least one entity of each with'ed
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-- unit is referenced (the latter check catches units that are only
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-- referenced in a use or package renaming statement). Appropriate
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-- warning messages are generated if either of these situations is
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-- detected.
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--
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-- A special case arises when a package body or a subprogram body with
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-- a separate spec is being compiled. In this case, a with may appear
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-- on the spec, but be needed only by the body. This still generates
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-- a warning, but the text is different (the with is not redundant,
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-- it is misplaced).
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--
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-- This special case is implemented by making an initial call to this
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-- procedure with Spec_Unit set to the unit number of the separate spec.
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-- This call does not generate any warning messages, but instead may
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-- result in flags being set in the N_With_Clause node that record that
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-- there was no use in the spec.
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--
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-- The main call (made after all units have been analyzed, with Spec_Unit
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-- set to the default value of No_Unit) generates the required warnings
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-- using the flags set by the initial call where appropriate to specialize
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-- the text of the warning messages.
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---------------------
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-- Output Routines --
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---------------------
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procedure Output_Unreferenced_Messages;
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-- Warnings about unreferenced entities are collected till the end of
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-- the compilation process (see Check_Unset_Reference for further
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-- details). This procedure outputs waiting warnings, if any.
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----------------------------
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-- Other Warning Routines --
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----------------------------
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procedure Warn_On_Known_Condition (C : Node_Id);
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-- C is a node for a boolean expression resluting from a relational
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-- or membership operation. If the expression has a compile time known
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-- value, then a warning is output if all the following conditions hold:
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--
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-- 1. Original expression comes from source. We don't want to generate
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-- warnings for internally generated conditionals.
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--
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-- 2. As noted above, the expression is a relational or membership
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-- test, we don't want to generate warnings for boolean variables
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-- since this is typical of conditional compilation in Ada.
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--
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-- 3. The expression appears in a statement, rather than a declaration.
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-- In practice, most occurrences in declarations are legitimate
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-- conditionalizations, but occurrences in statements are often
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-- errors for which the warning is useful.
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--
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-- 4. The expression does not occur within an instantiation. A non-
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-- static expression in a generic may become constant because of
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-- the attributes of the actuals, and we do not want to warn on
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-- these legitimate constant foldings.
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--
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-- If all these conditions are met, the warning is issued noting that
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-- the result of the test is always false or always true as appropriate.
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end Sem_Warn;
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