1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2009, 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 ------------------------------------------------------------------------------
26 with Types; use Types;
27 with Uintp; use Uintp;
30 procedure Analyze_At_Clause (N : Node_Id);
31 procedure Analyze_Attribute_Definition_Clause (N : Node_Id);
32 procedure Analyze_Enumeration_Representation_Clause (N : Node_Id);
33 procedure Analyze_Free_Statement (N : Node_Id);
34 procedure Analyze_Freeze_Entity (N : Node_Id);
35 procedure Analyze_Record_Representation_Clause (N : Node_Id);
36 procedure Analyze_Code_Statement (N : Node_Id);
38 procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id);
39 -- Called from Freeze where R is a record entity for which reverse bit
40 -- order is specified and there is at least one component clause. Adjusts
41 -- component positions according to either Ada 95 or Ada 2005 (AI-133).
43 procedure Check_Record_Representation_Clause (N : Node_Id);
44 -- This procedure completes the analysis of a record representation clause
45 -- N. It is called at freeze time after adjustment of component clause bit
46 -- positions for possible non-standard bit order. In the case of Ada 2005
47 -- (machine scalar) mode, this adjustment can make substantial changes, so
48 -- some checks, in particular for component overlaps cannot be done at the
49 -- time the record representation clause is first seen, but must be delayed
50 -- till freeze time, and in particular is called after calling the above
51 -- procedure for adjusting record bit positions for reverse bit order.
54 -- Initialize internal tables for new compilation
56 procedure Set_Enum_Esize (T : Entity_Id);
57 -- This routine sets the Esize field for an enumeration type T, based
58 -- on the current representation information available for T. Note that
59 -- the setting of the RM_Size field is not affected. This routine also
60 -- initializes the alignment field to zero.
64 Biased : Boolean := False) return Nat;
65 -- Given an elementary type, determines the minimum number of bits required
66 -- to represent all values of the type. This function may not be called
67 -- with any other types. If the flag Biased is set True, then the minimum
68 -- size calculation that biased representation is used in the case of a
69 -- discrete type, e.g. the range 7..8 gives a minimum size of 4 with
70 -- Biased set to False, and 1 with Biased set to True. Note that the
71 -- biased parameter only has an effect if the type is not biased, it
72 -- causes Minimum_Size to indicate the minimum size of an object with
73 -- the given type, of the size the type would have if it were biased. If
74 -- the type is already biased, then Minimum_Size returns the biased size,
75 -- regardless of the setting of Biased. Also, fixed-point types are never
76 -- biased in the current implementation. If the size is not known at
77 -- compile time, this function returns 0.
79 procedure Check_Constant_Address_Clause (Expr : Node_Id; U_Ent : Entity_Id);
80 -- Expr is an expression for an address clause. This procedure checks
81 -- that the expression is constant, in the limited sense that it is safe
82 -- to evaluate it at the point the object U_Ent is declared, rather than
83 -- at the point of the address clause. The condition for this to be true
84 -- is that the expression has no variables, no constants declared after
85 -- U_Ent, and no calls to non-pure functions. If this condition is not
86 -- met, then an appropriate error message is posted. This check is applied
87 -- at the point an object with an address clause is frozen, as well as for
88 -- address clauses for tasks and entries.
94 Biased : out Boolean);
95 -- Called when size Siz is specified for subtype T. This subprogram checks
96 -- that the size is appropriate, posting errors on node N as required.
97 -- This check is effective for elementary types and bit-packed arrays.
98 -- For other non-elementary types, a check is only made if an explicit
99 -- size has been given for the type (and the specified size must match).
100 -- The parameter Biased is set False if the size specified did not require
101 -- the use of biased representation, and True if biased representation
102 -- was required to meet the size requirement. Note that Biased is only
103 -- set if the type is not currently biased, but biasing it is the only
104 -- way to meet the requirement. If the type is currently biased, then
105 -- this biased size is used in the initial check, and Biased is False.
106 -- If the size is too small, and an error message is given, then both
107 -- Esize and RM_Size are reset to the allowed minimum value in T.
109 function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean;
110 -- Called at the start of processing a representation clause or a
111 -- representation pragma. Used to check that the representation item
112 -- is not being applied to an incomplete type or to a generic formal
113 -- type or a type derived from a generic formal type. Returns False if
114 -- no such error occurs. If this error does occur, appropriate error
115 -- messages are posted on node N, and True is returned.
117 function Rep_Item_Too_Late
120 FOnly : Boolean := False) return Boolean;
121 -- Called at the start of processing a representation clause or a
122 -- representation pragma. Used to check that a representation item
123 -- for entity T does not appear too late (according to the rules in
124 -- RM 13.1(9) and RM 13.1(10)). N is the associated node, which in
125 -- the pragma case is the pragma or representation clause itself, used
126 -- for placing error messages if the item is too late.
128 -- Fonly is a flag that causes only the freezing rule (para 9) to be
129 -- applied, and the tests of para 10 are skipped. This is appropriate
130 -- for both subtype related attributes (Alignment and Size) and for
131 -- stream attributes, which, although certainly not subtype related
132 -- attributes, clearly should not be subject to the para 10 restrictions
133 -- (see AI95-00137). Similarly, we also skip the para 10 restrictions for
134 -- the Storage_Size case where they also clearly do not apply, and for
135 -- Stream_Convert which is in the same category as the stream attributes.
137 -- If the rep item is too late, an appropriate message is output and
138 -- True is returned, which is a signal that the caller should abandon
139 -- processing for the item. If the item is not too late, then False
140 -- is returned, and the caller can continue processing the item.
142 -- If no error is detected, this call also as a side effect links the
143 -- representation item onto the head of the representation item chain
144 -- (referenced by the First_Rep_Item field of the entity).
146 -- Note: Rep_Item_Too_Late must be called with the underlying type in
147 -- the case of a private or incomplete type. The protocol is to first
148 -- check for Rep_Item_Too_Early using the initial entity, then take the
149 -- underlying type, then call Rep_Item_Too_Late on the result.
151 function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean;
152 -- Given two types, where the two types are related by possible derivation,
153 -- determines if the two types have the same representation, or different
154 -- representations, requiring the special processing for representation
155 -- change. A False result is possible only for array, enumeration or
158 procedure Validate_Unchecked_Conversion
160 Act_Unit : Entity_Id);
161 -- Validate a call to unchecked conversion. N is the node for the actual
162 -- instantiation, which is used only for error messages. Act_Unit is the
163 -- entity for the instantiation, from which the actual types etc. for this
164 -- instantiation can be determined. This procedure makes an entry in a
165 -- table and/or generates an N_Validate_Unchecked_Conversion node. The
166 -- actual checking is done in Validate_Unchecked_Conversions or in the
167 -- back end as required.
169 procedure Validate_Unchecked_Conversions;
170 -- This routine is called after calling the backend to validate
171 -- unchecked conversions for size and alignment appropriateness.
172 -- The reason it is called that late is to take advantage of any
173 -- back-annotation of size and alignment performed by the backend.
175 procedure Validate_Address_Clauses;
176 -- This is called after the back end has been called (and thus after the
177 -- alignments of objects have been back annotated). It goes through the
178 -- table of saved address clauses checking for suspicious alignments and
179 -- if necessary issuing warnings.
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