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Diffstat (limited to 'gcc-4.4.0/gcc/ada/sem_warn.ads')
| -rw-r--r-- | gcc-4.4.0/gcc/ada/sem_warn.ads | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/gcc-4.4.0/gcc/ada/sem_warn.ads b/gcc-4.4.0/gcc/ada/sem_warn.ads new file mode 100644 index 000000000..e3daef471 --- /dev/null +++ b/gcc-4.4.0/gcc/ada/sem_warn.ads @@ -0,0 +1,235 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ W A R N -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1999-2008, 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 3, 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 COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- 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 Alloc; use Alloc; +with Table; +with Types; use Types; + +package Sem_Warn is + + ------------------------ + -- Warnings Off Table -- + ------------------------ + + type Warnings_Off_Entry is record + N : Node_Id; + -- A pragma Warnings (Off, ent) node + + E : Entity_Id; + -- The entity involved + end record; + + -- An entry is made in the following table for any valid Pragma Warnings + -- (Off, entity) encountered while Opt.Warn_On_Warnings_Off is True. It + -- is used to generate warnings on any of these pragmas that turn out not + -- to be needed, or that could be replaced by Unmodified/Unreferenced. + + package Warnings_Off_Pragmas is new Table.Table ( + Table_Component_Type => Warnings_Off_Entry, + Table_Index_Type => Int, + Table_Low_Bound => 0, + Table_Initial => Alloc.Warnings_Off_Pragmas_Initial, + Table_Increment => Alloc.Warnings_Off_Pragmas_Increment, + Table_Name => "Name_Warnings_Off_Pragmas"); + + -------------------- + -- Initialization -- + -------------------- + + procedure Initialize; + -- Initialize this package for new compilation + + function Set_Warning_Switch (C : Character) return Boolean; + -- This function sets the warning switch or switches corresponding to the + -- given character. It is used to process a -gnatw switch on the command + -- line, or a character in a string literal in pragma Warnings. Returns + -- True for valid warning character C, False for invalid character. + + function Set_Dot_Warning_Switch (C : Character) return Boolean; + -- This function sets the warning switch or switches corresponding to the + -- given character preceded by a dot. Used to process a -gnatw. switch on + -- the command line or .C in a string literal in pragma Warnings. Returns + -- True for valid warning character C, False for invalid character. + + ------------------------------------------ + -- 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_Non_Modifed_In_Out_Warnings; + -- Warnings about IN OUT parameters that could be IN are collected till + -- the end of the compilation process (see body of this routine for a + -- discussion of why this is done). This procedure outputs the warnings. + -- Note: this should be called before Output_Unreferenced_Messages, since + -- if we have an IN OUT warning, that's the one we want to see! + + procedure Output_Obsolescent_Entity_Warnings (N : Node_Id; E : Entity_Id); + -- N is a reference to obsolescent entity E, for which appropriate warning + -- messages are to be generated (caller has already checked that warnings + -- are active and appropriate for this entity). + + 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. + + procedure Output_Unused_Warnings_Off_Warnings; + -- Warnings about pragma Warnings (Off, ent) statements that are unused, + -- or could be replaced by Unmodified/Unreferenced pragmas, are collected + -- till the end of the compilation process. This procedure outputs waiting + -- warnings if any. + + ---------------------------- + -- Other Warning Routines -- + ---------------------------- + + procedure Check_Code_Statement (N : Node_Id); + -- Perform warning checks on a code statement node + + procedure Check_Infinite_Loop_Warning (Loop_Statement : Node_Id); + -- N is the node for a loop statement. This procedure checks if a warning + -- should be given for a possible infinite loop, and if so issues it. + + procedure Warn_On_Known_Condition (C : Node_Id); + -- C is a node for a boolean expression resulting 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. + + function Warn_On_Modified_As_Out_Parameter (E : Entity_Id) return Boolean; + -- Returns True if we should activate warnings for entity E being modified + -- as an out parameter. True if either Warn_On_Modified_Unread is set for + -- an only OUT parameter, or if Warn_On_All_Unread_Out_Parameters is set. + + procedure Warn_On_Suspicious_Index (Name : Entity_Id; X : Node_Id); + -- This is called after resolving an indexed component or a slice. Name + -- is the entity for the name of the indexed array, and X is the subscript + -- for the indexed component case, or one of the bounds in the slice case. + -- If Name is an unconstrained parameter of a standard string type, and + -- the index is of the form of a literal or Name'Length [- literal], then + -- a warning is generated that the subscripting operation is possibly + -- incorrectly assuming a lower bound of 1. + + procedure Warn_On_Unassigned_Out_Parameter + (Return_Node : Node_Id; + Scope_Id : Entity_Id); + -- Called when processing a return statement given by Return_Node. Scope_Id + -- is the Entity_Id for the procedure in which the return statement lives. + -- A check is made for the case of a procedure with out parameters that + -- have not yet been assigned, and appropriate warnings are given. + + procedure Warn_On_Useless_Assignment + (Ent : Entity_Id; + N : Node_Id := Empty); + -- Called to check if we have a case of a useless assignment to the given + -- entity Ent, as indicated by a non-empty Last_Assignment field. This call + -- should only be made if at least one of the flags Warn_On_Modified_Unread + -- or Warn_On_All_Unread_Out_Parameters is True, and if Ent is in the + -- extended main source unit. N is Empty for the end of block call + -- (warning message says value unreferenced), or the it is the node for + -- an overwriting assignment (warning message points to this assignment). + + procedure Warn_On_Useless_Assignments (E : Entity_Id); + pragma Inline (Warn_On_Useless_Assignments); + -- Called at the end of a block or subprogram. Scans the entities of the + -- block or subprogram to see if there are any variables for which useless + -- assignments were made (assignments whose values were never read). + +end Sem_Warn; |