File : ali-util.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- A L I . U T I L --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2013, Free Software Foundation, Inc. --
10 -- --
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. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
26 -- This child unit provides utility data structures and procedures used
27 -- for manipulation of ALI data by the gnatbind and gnatmake.
28
29 package ALI.Util is
30
31 -----------------------
32 -- Source File Table --
33 -----------------------
34
35 -- A table entry is built for every source file that is in the source
36 -- dependency table of any ALI file that is part of the current program.
37
38 No_Source_Id : constant Source_Id := Source_Id'First;
39 -- Special value indicating no Source table entry
40
41 First_Source_Entry : constant Source_Id := No_Source_Id + 1;
42 -- Id of first actual entry in table
43
44 type Source_Record is record
45
46 Sfile : File_Name_Type;
47 -- Name of source file
48
49 Stamp : Time_Stamp_Type;
50 -- Time stamp value. If Check_Source_Files is set and the source
51 -- file is located, then Stamp is set from the source file. Otherwise
52 -- Stamp is set from the latest stamp value found in any of the
53 -- ALI files for the current program.
54
55 Source_Found : Boolean;
56 -- This flag is set to True if the corresponding source file was
57 -- located and the Stamp value was set from the actual source file.
58 -- It is always false if Check_Source_Files is not set.
59
60 Stamp_File : File_Name_Type;
61 -- File that Stamp came from. If Source_Found is True, then Stamp is the
62 -- timestamp of the source file, and this is the name of the source
63 -- file. If Source_Found is False, then Stamp comes from a dependency
64 -- line in an ALI file, this is the name of that ALI file. Used only in
65 -- verbose mode, for messages.
66
67 All_Timestamps_Match : Boolean;
68 -- This flag is set only if all files referencing this source file
69 -- have a matching time stamp, and also, if Source_Found is True,
70 -- then the stamp of the source file also matches. If this flag is
71 -- True, then checksums for this file are never referenced. We only
72 -- use checksums if there are time stamp mismatches.
73
74 All_Checksums_Match : Boolean;
75 -- This flag is set only if all files referencing this source file
76 -- have checksums, and if all these checksums match. If this flag
77 -- is set to True, then the binder will ignore a timestamp mismatch.
78 -- An absent checksum causes this flag to be set False, and a mismatch
79 -- of checksums also causes it to be set False. The checksum of the
80 -- actual source file (if Source_Found is True) is included only if
81 -- All_Timestamps_Match is False (since checksums are only interesting
82 -- if we have time stamp mismatches, and we want to avoid computing the
83 -- checksum of the source file if it is not needed.)
84
85 Checksum : Word;
86 -- If no dependency line has a checksum for this source file (i.e. the
87 -- corresponding entries in the source dependency records all have the
88 -- Checksum_Present flag set False), then this field is undefined. If
89 -- at least one dependency entry has a checksum present, then this
90 -- field contains one of the possible checksum values that has been
91 -- seen. This is used to set All_Checksums_Match properly.
92
93 end record;
94
95 package Source is new Table.Table (
96 Table_Component_Type => Source_Record,
97 Table_Index_Type => Source_Id,
98 Table_Low_Bound => First_Source_Entry,
99 Table_Initial => 1000,
100 Table_Increment => 200,
101 Table_Name => "Source");
102
103 procedure Initialize_ALI_Source;
104 -- Initialize Source table
105
106 --------------------------------------------------
107 -- Subprograms for Manipulating ALI Information --
108 --------------------------------------------------
109
110 procedure Read_Withed_ALIs
111 (Id : ALI_Id;
112 Ignore_Errors : Boolean := False);
113 -- Process an ALI file which has been read and scanned by looping through
114 -- all withed units in the ALI file, checking if they have been processed.
115 -- Each unit that has not yet been processed will be read, scanned, and
116 -- processed recursively. If Ignore_Errors is True, then failure to read an
117 -- ALI file is not reported as an error, and scanning continues with other
118 -- ALI files.
119
120 procedure Set_Source_Table (A : ALI_Id);
121 -- Build source table entry corresponding to the ALI file whose id is A
122
123 procedure Set_Source_Table;
124 -- Build the entire source table
125
126 function Time_Stamp_Mismatch
127 (A : ALI_Id;
128 Read_Only : Boolean := False) return File_Name_Type;
129 -- Looks in the Source_Table and checks time stamp mismatches between
130 -- the sources there and the sources in the Sdep section of ali file whose
131 -- id is A. If no time stamp mismatches are found No_File is returned.
132 -- Otherwise return the first file for which there is a mismatch.
133 -- Note that in check source files mode (Check_Source_Files = True), the
134 -- time stamp in the Source_Table should be the actual time stamp of the
135 -- source files. In minimal recompilation mode (Minimal_Recompilation set
136 -- to True, no mismatch is found if the file's timestamp has not changed.
137 -- If Read_Only is True, missing sources are not considered.
138
139 --------------------------------------------
140 -- Subprograms for manipulating checksums --
141 --------------------------------------------
142
143 Checksum_Error : constant Word := 16#FFFF_FFFF#;
144 -- This value is used to indicate an error in computing the checksum.
145 -- When comparing checksums for smart recompilation, the CRC_Error
146 -- value is never considered to match. This could possibly result
147 -- in a false negative, but that is never harmful, it just means
148 -- that in unusual cases an unnecessary recompilation occurs.
149
150 function Get_File_Checksum (Fname : File_Name_Type) return Word;
151 -- Compute checksum for the given file. As far as possible, this circuit
152 -- computes exactly the same value computed by the compiler, but it does
153 -- not matter if it gets it wrong in marginal cases, since the only result
154 -- is to miss some smart recompilation cases, correct functioning is not
155 -- affected by a miscomputation. Returns Checksum_Error if the file is
156 -- missing or has an error.
157
158 function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean;
159 pragma Inline (Checksums_Match);
160 -- Returns True if Checksum1 and Checksum2 have the same value and are
161 -- not equal to Checksum_Error, returns False in all other cases. This
162 -- routine must always be used to compare for checksum equality, to
163 -- ensure that the case of Checksum_Error is handled properly.
164
165 end ALI.Util;