diff options
Diffstat (limited to 'gcc-4.2.1/gcc/ada/sem_warn.ads')
| -rw-r--r-- | gcc-4.2.1/gcc/ada/sem_warn.ads | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/gcc-4.2.1/gcc/ada/sem_warn.ads b/gcc-4.2.1/gcc/ada/sem_warn.ads new file mode 100644 index 000000000..be2fd6f11 --- /dev/null +++ b/gcc-4.2.1/gcc/ada/sem_warn.ads @@ -0,0 +1,135 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ W A R N -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1999-2005, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 2, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, USA. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +-- This package contains the routines used to deal with issuing warnings +-- about uses of uninitialized variables and unused with's. It also has +-- some unrelated routines related to the generation of warnings. + +with Types; use Types; + +package Sem_Warn is + + -------------------- + -- Initialization -- + -------------------- + + function Set_Warning_Switch (C : Character) return Boolean; + -- This function sets the warning switch or switches corresponding to + -- the given character. It is used for processing a -gnatw switch on the + -- command line, or a string literal in pragma Warnings. + + ------------------------------------------ + -- Routines to Handle Unused References -- + ------------------------------------------ + + procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty); + -- Called at the end of processing a declarative region. The entity E + -- is the entity for the scope. All entities declared in the region, + -- as indicated by First_Entity and the entity chain, are checked to + -- see if they are variables for which warnings need to be posted for + -- either no assignments, or a use before an assignment or no references + -- at all. The Anod node is present for the case of an accept statement, + -- and references the accept statement. This is used to place the warning + -- messages in the right place. + + procedure Check_Unset_Reference (N : Node_Id); + -- N is the node for an expression which occurs in a reference position, + -- e.g. as the right side of an assignment. This procedure checks to see + -- if the node is a reference to a variable entity where the entity has + -- Not_Assigned set. If so, the Unset_Reference field is set if it is not + -- the first occurrence. No warning is posted, instead warnings will be + -- posted later by Check_References. The reason we do things that + -- way is that if there are no assignments anywhere, we prefer to flag + -- the entity, rather than a reference to it. Note that for the purposes + -- of this routine, a type conversion or qualified expression whose + -- expression is an entity is also processed. The reason that we do not + -- process these at the point of occurrence is that both these constructs + -- can occur in non-reference positions (e.g. as out parameters). + + procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit); + -- This routine performs two kinds of checks. It checks that all with'ed + -- units are referenced, and that at least one entity of each with'ed + -- unit is referenced (the latter check catches units that are only + -- referenced in a use or package renaming statement). Appropriate + -- warning messages are generated if either of these situations is + -- detected. + -- + -- A special case arises when a package body or a subprogram body with + -- a separate spec is being compiled. In this case, a with may appear + -- on the spec, but be needed only by the body. This still generates + -- a warning, but the text is different (the with is not redundant, + -- it is misplaced). + -- + -- This special case is implemented by making an initial call to this + -- procedure with Spec_Unit set to the unit number of the separate spec. + -- This call does not generate any warning messages, but instead may + -- result in flags being set in the N_With_Clause node that record that + -- there was no use in the spec. + -- + -- The main call (made after all units have been analyzed, with Spec_Unit + -- set to the default value of No_Unit) generates the required warnings + -- using the flags set by the initial call where appropriate to specialize + -- the text of the warning messages. + + --------------------- + -- Output Routines -- + --------------------- + + procedure Output_Unreferenced_Messages; + -- Warnings about unreferenced entities are collected till the end of + -- the compilation process (see Check_Unset_Reference for further + -- details). This procedure outputs waiting warnings, if any. + + ---------------------------- + -- Other Warning Routines -- + ---------------------------- + + procedure Warn_On_Known_Condition (C : Node_Id); + -- C is a node for a boolean expression resluting from a relational + -- or membership operation. If the expression has a compile time known + -- value, then a warning is output if all the following conditions hold: + -- + -- 1. Original expression comes from source. We don't want to generate + -- warnings for internally generated conditionals. + -- + -- 2. As noted above, the expression is a relational or membership + -- test, we don't want to generate warnings for boolean variables + -- since this is typical of conditional compilation in Ada. + -- + -- 3. The expression appears in a statement, rather than a declaration. + -- In practice, most occurrences in declarations are legitimate + -- conditionalizations, but occurrences in statements are often + -- errors for which the warning is useful. + -- + -- 4. The expression does not occur within an instantiation. A non- + -- static expression in a generic may become constant because of + -- the attributes of the actuals, and we do not want to warn on + -- these legitimate constant foldings. + -- + -- If all these conditions are met, the warning is issued noting that + -- the result of the test is always false or always true as appropriate. + +end Sem_Warn; |