1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
27 with Types; use Types;
28 with Uintp; use Uintp;
31 procedure Analyze_At_Clause (N : Node_Id);
32 procedure Analyze_Attribute_Definition_Clause (N : Node_Id);
33 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id);
34 procedure Analyze_Free_Statement (N : Node_Id);
35 procedure Analyze_Freeze_Entity (N : Node_Id);
36 procedure Analyze_Record_Representation_Clause (N : Node_Id);
37 procedure Analyze_Code_Statement (N : Node_Id);
39 procedure Analyze_Aspect_Specifications
43 -- This procedure is called to analyze aspect spefications for node N. E is
44 -- the corresponding entity declared by the declaration node N, and L is
45 -- the list of aspect specifications for this node. If L is No_List, the
46 -- call is ignored. Note that we can't use a simpler interface of just
47 -- passing the node N, since the analysis of the node may cause it to be
48 -- rewritten to a node not permitting aspect specifications.
50 procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id);
51 -- Called from Freeze where R is a record entity for which reverse bit
52 -- order is specified and there is at least one component clause. Adjusts
53 -- component positions according to either Ada 95 or Ada 2005 (AI-133).
55 procedure Build_Invariant_Procedure
59 -- If Typ has Invariants (indicated by Has_Invariants being set for Typ,
60 -- indicating the presence of pragma Invariant entries on the rep chain,
61 -- note that Invariant aspects are converted to pragma Invariant), then
62 -- this procedure builds the spec and body for the corresponding Invariant
63 -- procedure, returning themn in PDecl and PBody. Invariant_Procedure is
64 -- set for Typ. In some error situations no procedure is built, in which
65 -- case PDecl/PBody are empty on return.
67 procedure Check_Record_Representation_Clause (N : Node_Id);
68 -- This procedure completes the analysis of a record representation clause
69 -- N. It is called at freeze time after adjustment of component clause bit
70 -- positions for possible non-standard bit order. In the case of Ada 2005
71 -- (machine scalar) mode, this adjustment can make substantial changes, so
72 -- some checks, in particular for component overlaps cannot be done at the
73 -- time the record representation clause is first seen, but must be delayed
74 -- till freeze time, and in particular is called after calling the above
75 -- procedure for adjusting record bit positions for reverse bit order.
78 -- Initialize internal tables for new compilation
80 procedure Set_Enum_Esize (T : Entity_Id);
81 -- This routine sets the Esize field for an enumeration type T, based
82 -- on the current representation information available for T. Note that
83 -- the setting of the RM_Size field is not affected. This routine also
84 -- initializes the alignment field to zero.
88 Biased : Boolean := False) return Nat;
89 -- Given an elementary type, determines the minimum number of bits required
90 -- to represent all values of the type. This function may not be called
91 -- with any other types. If the flag Biased is set True, then the minimum
92 -- size calculation that biased representation is used in the case of a
93 -- discrete type, e.g. the range 7..8 gives a minimum size of 4 with
94 -- Biased set to False, and 1 with Biased set to True. Note that the
95 -- biased parameter only has an effect if the type is not biased, it
96 -- causes Minimum_Size to indicate the minimum size of an object with
97 -- the given type, of the size the type would have if it were biased. If
98 -- the type is already biased, then Minimum_Size returns the biased size,
99 -- regardless of the setting of Biased. Also, fixed-point types are never
100 -- biased in the current implementation. If the size is not known at
101 -- compile time, this function returns 0.
103 procedure Check_Constant_Address_Clause (Expr : Node_Id; U_Ent : Entity_Id);
104 -- Expr is an expression for an address clause. This procedure checks
105 -- that the expression is constant, in the limited sense that it is safe
106 -- to evaluate it at the point the object U_Ent is declared, rather than
107 -- at the point of the address clause. The condition for this to be true
108 -- is that the expression has no variables, no constants declared after
109 -- U_Ent, and no calls to non-pure functions. If this condition is not
110 -- met, then an appropriate error message is posted. This check is applied
111 -- at the point an object with an address clause is frozen, as well as for
112 -- address clauses for tasks and entries.
118 Biased : out Boolean);
119 -- Called when size Siz is specified for subtype T. This subprogram checks
120 -- that the size is appropriate, posting errors on node N as required.
121 -- This check is effective for elementary types and bit-packed arrays.
122 -- For other non-elementary types, a check is only made if an explicit
123 -- size has been given for the type (and the specified size must match).
124 -- The parameter Biased is set False if the size specified did not require
125 -- the use of biased representation, and True if biased representation
126 -- was required to meet the size requirement. Note that Biased is only
127 -- set if the type is not currently biased, but biasing it is the only
128 -- way to meet the requirement. If the type is currently biased, then
129 -- this biased size is used in the initial check, and Biased is False.
130 -- If the size is too small, and an error message is given, then both
131 -- Esize and RM_Size are reset to the allowed minimum value in T.
133 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean;
134 -- Called at the start of processing a representation clause or a
135 -- representation pragma. Used to check that the representation item
136 -- is not being applied to an incomplete type or to a generic formal
137 -- type or a type derived from a generic formal type. Returns False if
138 -- no such error occurs. If this error does occur, appropriate error
139 -- messages are posted on node N, and True is returned.
141 function Rep_Item_Too_Late
144 FOnly : Boolean := False) return Boolean;
145 -- Called at the start of processing a representation clause or a
146 -- representation pragma. Used to check that a representation item
147 -- for entity T does not appear too late (according to the rules in
148 -- RM 13.1(9) and RM 13.1(10)). N is the associated node, which in
149 -- the pragma case is the pragma or representation clause itself, used
150 -- for placing error messages if the item is too late.
152 -- Fonly is a flag that causes only the freezing rule (para 9) to be
153 -- applied, and the tests of para 10 are skipped. This is appropriate
154 -- for both subtype related attributes (Alignment and Size) and for
155 -- stream attributes, which, although certainly not subtype related
156 -- attributes, clearly should not be subject to the para 10 restrictions
157 -- (see AI95-00137). Similarly, we also skip the para 10 restrictions for
158 -- the Storage_Size case where they also clearly do not apply, and for
159 -- Stream_Convert which is in the same category as the stream attributes.
161 -- If the rep item is too late, an appropriate message is output and
162 -- True is returned, which is a signal that the caller should abandon
163 -- processing for the item. If the item is not too late, then False
164 -- is returned, and the caller can continue processing the item.
166 -- If no error is detected, this call also as a side effect links the
167 -- representation item onto the head of the representation item chain
168 -- (referenced by the First_Rep_Item field of the entity).
170 -- Note: Rep_Item_Too_Late must be called with the underlying type in
171 -- the case of a private or incomplete type. The protocol is to first
172 -- check for Rep_Item_Too_Early using the initial entity, then take the
173 -- underlying type, then call Rep_Item_Too_Late on the result.
175 -- Note: Calls to Rep_Item_Too_Late are ignored for the case of attribute
176 -- definition clauses which have From_Aspect_Specification set. This is
177 -- because such clauses are linked on to the Rep_Item chain in procedure
178 -- Sem_Ch13.Analyze_Aspect_Specifications. See that procedure for details.
180 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean;
181 -- Given two types, where the two types are related by possible derivation,
182 -- determines if the two types have the same representation, or different
183 -- representations, requiring the special processing for representation
184 -- change. A False result is possible only for array, enumeration or
187 procedure Validate_Unchecked_Conversion
189 Act_Unit : Entity_Id);
190 -- Validate a call to unchecked conversion. N is the node for the actual
191 -- instantiation, which is used only for error messages. Act_Unit is the
192 -- entity for the instantiation, from which the actual types etc. for this
193 -- instantiation can be determined. This procedure makes an entry in a
194 -- table and/or generates an N_Validate_Unchecked_Conversion node. The
195 -- actual checking is done in Validate_Unchecked_Conversions or in the
196 -- back end as required.
198 procedure Validate_Unchecked_Conversions;
199 -- This routine is called after calling the backend to validate unchecked
200 -- conversions for size and alignment appropriateness. The reason it is
201 -- called that late is to take advantage of any back-annotation of size
202 -- and alignment performed by the backend.
204 procedure Validate_Address_Clauses;
205 -- This is called after the back end has been called (and thus after the
206 -- alignments of objects have been back annotated). It goes through the
207 -- table of saved address clauses checking for suspicious alignments and
208 -- if necessary issuing warnings.
210 procedure Validate_Independence;
211 -- This is called after the back end has been called (and thus after the
212 -- layout of components has been back annotated). It goes through the
213 -- table of saved pragma Independent[_Component] entries, checking that
214 -- independence can be achieved, and if necessary issuing error mssags.
216 -------------------------------------
217 -- Table for Validate_Independence --
218 -------------------------------------
220 -- If a legal pragma Independent or Independent_Components is given for
221 -- an entity, then an entry is made in this table, to be checked by a
222 -- call to Validate_Independence after back annotation of layout is done.
224 type Independence_Check_Record is record
226 -- The pragma Independent or Independent_Components
229 -- The entity to which it applies
232 package Independence_Checks is new Table.Table (
233 Table_Component_Type => Independence_Check_Record,
234 Table_Index_Type => Int,
235 Table_Low_Bound => 1,
237 Table_Increment => 200,
238 Table_Name => "Independence_Checks");
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