------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- L I B . W R I T -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2005, 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 for writing the library information package Lib.Writ is ----------------------------------- -- Format of Library Information -- ----------------------------------- -- This section describes the format of the library information that is -- associated with object files. The exact method of this association is -- potentially implementation dependent and is described and implemented -- in package ali. From the point of view of the description here, all we -- need to know is that the information is represented as a string of -- characters that is somehow associated with an object file, and can be -- retrieved. If no library information exists for a given object file, -- then we take this as equivalent to the non-existence of the object -- file, as if source file has not been previously compiled. -- The library information is written as a series of lines of the form: -- Key_Character parameter parameter ... -- The following sections describe the format of these lines in detail -------------------------------------- -- Making Changes to the ALI Format -- -------------------------------------- -- A number of tools use ali.adb to parse ali files. This means -- that changes to this format can cause old versions of these tools -- to be incompatible with new versions of the compiler. Any changes -- to ali file formats must be carefully evaluated to understand any -- such possible conflicts, and in particular, it is very undesirable -- to create conflicts between older versions of GPS and newer versions -- of the compiler. -- If the following guidelines are respected, downward compatibility -- problems (old tools reading new ali files) should be minimized: -- The basic key character format must be kept -- The V line must be the first line, this is checked by ali.adb -- even in Ignore_Errors mode, and is used to verify that the file -- at hand is indeed likely intended to be an ali file. -- The P line must be present, though may be modified in contents -- according to remaining guidelines. Again, ali.adb assumes the -- P line is present even in Ignore_Errors mode. -- New modifiers can generally be added (in particular adding new -- two letter modifiers to the P or U lines is always safe) -- Adding entirely new lines (with a new key letter) to the ali -- file is always safe, at any point (other than before the V -- line), since suchy lines will be ignored. -- Following the guidelines in this section should ensure that this -- problem is minimized and that old tools will be able to deal -- successfully with new ali formats. Note that this does not apply -- to the compiler itself, which always requires consistency between -- the ali files and the binder. That is because one of the main -- functions of the binder is to ensure consistency of the partition, -- and this can be compromised if the ali files are inconsistent. ------------------ -- Header Lines -- ------------------ -- The initial header lines in the file give information about the -- compilation environment, and identify other special information -- such as main program parameters. -- ---------------- -- -- V Version -- -- ---------------- -- V "xxxxxxxxxxxxxxxx" -- -- This line indicates the library output version, as defined in -- Gnatvsn. It ensures that separate object modules of a program are -- consistent. It has to be changed if anything changes which would -- affect successful binding of separately compiled modules. -- Examples of such changes are modifications in the format of the -- library info described in this package, or modifications to -- calling sequences, or to the way that data is represented. -- Note: the V line absolutely must be the first line, and no change -- to the ALI format should change this, since even in Ignore_Errors -- mode, Scan_ALI insists on finding a V line. -- --------------------- -- -- M Main Program -- -- --------------------- -- M type [priority] [T=time-slice] W=? -- This line appears only if the main unit for this file is -- suitable for use as a main program. The parameters are: -- type -- P for a parameterless procedure -- F for a function returning a value of integral type -- (used for writing a main program returning an exit status) -- priority -- Present only if there was a valid pragma Priority in the -- corresponding unit to set the main task priority. It is -- an unsigned decimal integer. -- T=time-slice -- Present only if there was a valid pragma Time_Slice in the -- corresponding unit. It is an unsigned decimal integer in -- the range 0 .. 10**9 giving the time slice value in units -- of milliseconds. The actual significance of this parameter -- is target dependent. -- W=? -- This parameter indicates the wide character encoding -- method used when compiling the main program file. The ? -- character is the single character used in the -gnatW? -- switch. This is used to provide the default wide-character -- encoding for Wide_Text_IO files. -- ----------------- -- -- A Argument -- -- ----------------- -- A argument -- One of these lines appears for each of the arguments present -- in the call to the gnat1 program. This can be used if it is -- necessary to reconstruct this call (e.g. for fix and continue) -- ------------------- -- -- P Parameters -- -- ------------------- -- P <<parameters>> -- Indicates various information that applies to the compilation -- of the corresponding source unit. Parameters is a sequence of -- zero or more two letter codes that indicate configuration -- pragmas and other parameters that apply: -- -- The arguments are as follows: -- -- CE Compilation errors. If this is present it means that the -- ali file resulted from a compilation with the -gnatQ -- switch set, and illegalities were detected. The ali -- file contents may not be completely reliable, but the -- format will be correct and complete. Note that NO is -- always present if CE is present. -- -- DB Detect_Blocking pragma is in effect for all units in -- this file. -- -- FD Configuration pragmas apply to all the units in this -- file specifying a possibly non-standard floating point -- format (VAX float with Long_Float using D_Float) -- -- FG Configuration pragmas apply to all the units in this -- file specifying a possibly non-standard floating point -- format (VAX float with Long_Float using G_Float) -- -- FI Configuration pragmas apply to all the units in this -- file specifying a possibly non-standard floating point -- format (IEEE Float) -- -- Lx A valid Locking_Policy pragma applies to all the units -- in this file, where x is the first character (upper case) -- of the policy name (e.g. 'C' for Ceiling_Locking) -- -- NO No object. This flag indicates that the units in this -- file were not compiled to produce an object. This can -- occur as a result of the use of -gnatc, or if no object -- can be produced (e.g. when a package spec is compiled -- instead of the body, or a subunit on its own). -- -- NR No_Run_Time. Indicates that a pragma No_Run_Time applies -- to all units in the file. -- -- NS Normalize_Scalars pragma in effect for all units in -- this file -- -- Qx A valid Queueing_Policy pragma applies to all the units -- in this file, where x is the first character (upper case) -- of the policy name (e.g. 'P' for Priority_Queueing). -- -- SL Indicates that the unit is an Interface to a Standalone -- Library. Note that this indication is never given by the -- compiler, but is added by the Project Manager in gnatmake -- when an Interface ALI file is copied to the library -- directory. -- SS This unit references System.Secondary_Stack (that is, -- the unit makes use of the secondary stack facilities). -- -- Tx A valid Task_Dispatching_Policy pragma applies to all -- the units in this file, where x is the first character -- (upper case) of the corresponding policy name (e.g. 'F' -- for FIFO_Within_Priorities). -- -- UA Unreserve_All_Interrupts pragma was processed in one or -- more units in this file -- -- ZX Units in this file use zero-cost exceptions and have -- generated exception tables. If ZX is not present, the -- longjmp/setjmp exception scheme is in use. -- -- Note that language defined units never output policy (Lx,Tx,Qx) -- parameters. Language defined units must correctly handle all -- possible cases. These values are checked for consistency by the -- binder and then copied to the generated binder output file. -- Note: The P line must be present. Even in Ignore_Errors mode, -- Scan_ALI insists on finding a P line. So if changes are made to -- the ALI format, they should not include removing the P line! -- --------------------- -- -- R Restrictions -- -- --------------------- -- The first R line records the status of restrictions generated by pragma -- Restrictions encountered, as well as information on what the compiler -- has been able to determine with respect to restrictions violations. -- The format is: -- R <<restriction-characters>> <<restriction-param-id-entries>> -- The first parameter is a string of characters that records -- information regarding restrictions that do not take parameter -- not take parameter values. It is a string of characters, one -- character for each value (in order) in All_Boolean_Restrictions. -- There are three possible settings for each restriction: -- r Restricted. Unit was compiled under control of a pragma -- Restrictions for the corresponding restriction. In -- this case the unit certainly does not violate the -- Restriction, since this would have been detected by -- the compiler. -- n Not used. The unit was not compiled under control of a -- pragma Restrictions for the corresponding restriction, -- and does not make any use of the referenced feature. -- v Violated. The unit was not compiled under control of a -- pragma Restrictions for the corresponding restriction, -- and it does indeed use the referenced feature. -- This information is used in the binder to check consistency, -- i.e. to detect cases where one unit has "r" and another unit -- has "v", which is not permitted, since these restrictions -- are partition-wide. -- The second parameter, which immediately follows the first (with -- no separating space) gives restriction information for identifiers -- for which a parameter is given. -- The parameter is a string of entries, one for each value in -- Restrict.All_Parameter_Restrictions. Each entry has two -- components in sequence, the first indicating whether or not -- there is a restriction, and the second indicating whether -- or not the compiler detected violations. In the boolean case -- it is not necessary to separate these, since if a restriction -- is set, and violated, that is an error. But in the parameter -- case, this is not true. For example, we can have a unit with -- a pragma Restrictions (Max_Tasks => 4), where the compiler -- can detect that there are exactly three tasks declared. Both -- of these pieces of information must be passed to the binder. -- The parameter of 4 is important in case the total number of -- tasks in the partition is greater than 4. The parameter of -- 3 is important in case some other unit has a restrictions -- pragma with Max_Tasks=>2. -- The component for the presence of restriction has one of two -- possible forms: -- n No pragma for this restriction is present in the -- set of units for this ali file. -- rN At least one pragma for this restriction is present -- in the set of units for this ali file. The value N -- is the minimum parameter value encountered in any -- such pragma. N is in the range of Integer (a value -- larger than N'Last causes the pragma to be ignored). -- The component for the violation detection has one of three -- possible forms: -- n No violations were detected by the compiler -- vN A violation was detected. N is either the maximum or total -- count of violations (depending on the checking type) in -- all the units represented by the ali file). Note that -- this setting is only allowed for restrictions that are -- in Checked_[Max|Sum]_Parameter_Restrictions. The value -- here is known to be exact by the compiler and is in the -- range of Natural. -- vN+ A violation was detected. The compiler cannot determine -- the exact count of violations, but it is at least N. -- There are no spaces within the parameter string, so the entry -- described above in the header of this section for Max_Tasks would -- appear as the string r4v3. -- Note: The restrictions line is required to be present. Even in -- Ignore_Errors mode, Scan_ALI expects to find an R line and will -- signal a fatal error if it is missing. This means that future -- changes to the ALI file format must retain the R line. -- Subsequent R lines are present only if pragma Restriction No_Dependence -- is used. There is one such line for each such pragma appearing in the -- extended main unit. The format is -- R unit_name -- Here the unit name is in all lower case. The components of the unit -- name are separated by periods. The names themselves are in encoded -- form, as documented in Namet. -- ------------------------ -- -- I Interrupt States -- -- ------------------------ -- I interrupt-number interrupt-state line-number -- This line records information from an Interrupt_State pragma. -- There is one line for each separate pragma, and if no such -- pragmas are used, then no I lines are present. -- The interrupt-number is an unsigned positive integer giving -- the value of the interrupt as defined in Ada.Interrupts.Names. -- The interrupt-state is one of r/s/u for Runtime/System/User -- The line number is an unsigned decimal integer giving the -- line number of the corresponding Interrupt_State pragma. -- This is used in consistency messages. ---------------------------- -- Compilation Unit Lines -- ---------------------------- -- Following these header lines, a set of information lines appears for -- each compilation unit that appears in the corresponding object file. -- In particular, when a package body or subprogram body is compiled, -- there will be two sets of information, one for the spec and one for -- the body. with the entry for the body appearing first. This is the -- only case in which a single ALI file contains more than one unit (in -- particular note that subunits do *not* count as compilation units for -- this purpose, and generate no library information, since they are -- inlined). -- -------------------- -- -- U Unit Header -- -- -------------------- -- The lines for each compilation unit have the following form -- U unit-name source-name version <<attributes>> -- -- This line identifies the unit to which this section of the -- library information file applies. The first three parameters are -- the unit name in internal format, as described in package Uname, -- and the name of the source file containing the unit. -- -- Version is the version given as eight hexadecimal characters -- with upper case letters. This value is the exclusive or of the -- source checksums of the unit and all its semantically dependent -- units. -- -- The <<attributes>> are a series of two letter codes indicating -- information about the unit: -- -- DE Dynamic Elaboration. This unit was compiled with the -- dynamic elaboration model, as set by either the -gnatE -- switch or pragma Elaboration_Checks (Dynamic). -- -- EB Unit has pragma Elaborate_Body -- -- EE Elaboration entity is present which must be set true when -- the unit is elaborated. The name of the elaboration entity -- is formed from the unit name in the usual way. If EE is -- present, then this boolean must be set True as part of the -- elaboration processing routine generated by the binder. -- Note that EE can be set even if NE is set. This happens -- when the boolean is needed solely for checking for the -- case of access before elaboration. -- -- GE Unit is a generic declaration, or corresponding body -- -- IL Unit source uses a style with identifiers in all lower -- IU case (IL) or all upper case (IU). If the standard mixed- -- case usage is detected, or the compiler cannot determine -- the style, then no I parameter will appear. -- -- IS Initialize_Scalars pragma applies to this unit -- -- KM Unit source uses a style with keywords in mixed case -- KU (KM) or all upper case (KU). If the standard lower-case -- usage is detected, or the compiler cannot determine the -- style, then no K parameter will appear. -- -- NE Unit has no elaboration routine. All subprogram bodies -- and specs are in this category. Package bodies and specs -- may or may not have NE set, depending on whether or not -- elaboration code is required. Set if N_Compilation_Unit -- node has flag Has_No_Elaboration_Code set. -- -- PK Unit is package, rather than a subprogram -- -- PU Unit has pragma Pure -- -- PR Unit has pragma Preelaborate -- -- RA Unit declares a Remote Access to Class-Wide (RACW) type -- -- RC Unit has pragma Remote_Call_Interface -- -- RT Unit has pragma Remote_Types -- -- SP Unit has pragma Shared_Passive. -- -- SU Unit is a subprogram, rather than a package -- -- The attributes may appear in any order, separated by spaces. -- --------------------- -- -- W Withed Units -- -- --------------------- -- Following each U line, is a series of lines of the form -- W unit-name [source-name lib-name] [E] [EA] [ED] [AD] -- -- One of these lines is present for each unit that is mentioned in -- an explicit with clause by the current unit. The first parameter -- is the unit name in internal format. The second parameter is the -- file name of the file that must be compiled to compile this unit. -- It is usually the file for the body, except for packages -- which have no body; for units that need a body, if the source file -- for the body cannot be found, the file name of the spec is used -- instead. The third parameter is the file name of the library -- information file that contains the results of compiling this unit. -- The optional modifiers are used as follows: -- -- E pragma Elaborate applies to this unit -- -- EA pragma Elaborate_All applies to this unit -- -- ED Elaborate_Desirable set for this unit, which means -- that there is no Elaborate, but the analysis suggests -- that Program_Error may be raised if the Elaborate -- conditions cannot be satisfied. The binder will attempt -- to treat ED as E if it can. -- -- AD Elaborate_All_Desirable set for this unit, which means -- that there is no Elaborate_All, but the analysis suggests -- that Program_Error may be raised if the Elaborate_All -- conditions cannot be satisfied. The binder will attempt -- to treat AD as EA if it can. -- -- The parameter source-name and lib-name are omitted for the case -- of a generic unit compiled with earlier versions of GNAT which -- did not generate object or ali files for generics. -- ----------------------- -- -- L Linker_Options -- -- ----------------------- -- Following the W lines (if any, or the U line if not), are an -- optional series of lines that indicates the usage of the pragma -- Linker_Options in the associated unit. For each appearence of a -- pragma Linker_Options (or Link_With) in the unit, a line is -- present with the form: -- L "string" -- where string is the string from the unit line enclosed in quotes. -- Within the quotes the following can occur: -- c graphic characters in range 20-7E other than " or { -- "" indicating a single " character -- {hh} indicating a character whose code is hex hh (0-9,A-F) -- {00} [ASCII.NUL] is used as a separator character -- to separate multiple arguments of a single -- Linker_Options pragma. -- For further details, see Stringt.Write_String_Table_Entry. Note -- that wide characters in the form {hhhh} cannot be produced, since -- pragma Linker_Option accepts only String, not Wide_String. -- The L lines are required to appear in the same order as the -- corresponding Linker_Options (or Link_With) pragmas appear in -- the source file, so that this order is preserved by the binder -- in constructing the set of linker arguments. --------------------- -- Reference Lines -- --------------------- -- The reference lines contain information about references from -- any of the units in the compilation (including, body version -- and version attributes, linker options pragmas and source -- dependencies. -- ------------------------------------ -- -- E External Version References -- -- ------------------------------------ -- One of these lines is present for each use of 'Body_Version or -- 'Version in any of the units of the compilation. These are used -- by the linker to determine which version symbols must be output. -- The format is simply: -- E name -- where name is the external name, i.e. the unit name with either -- a S or a B for spec or body version referenced (Body_Version -- always references the body, Version references the Spec, except -- in the case of a reference to a subprogram with no separate spec). -- Upper half and wide character codes are encoded using the same -- method as in Namet (Uhh for upper half, Whhhh for wide character, -- where hh are hex digits). -- --------------------- -- -- D Dependencies -- -- --------------------- -- The dependency lines indicate the source files on which the compiled -- units depend. This is used by the binder for consistency checking. -- These lines are also referenced by the cross-reference information. -- D source-name time-stamp checksum [subunit-name] line:file-name -- The time-stamp field contains the time stamp of the -- corresponding source file. See types.ads for details on -- time stamp representation. -- The checksum is an 8-hex digit representation of the source -- file checksum, with letters given in lower case. -- The subunit name is present only if the dependency line is for -- a subunit. It contains the fully qualified name of the subunit -- in all lower case letters. -- The line:file-name entry is present only if a Source_Reference -- pragma appeared in the source file identified by source-name. -- In this case, it gives the information from this pragma. Note -- that this allows cross-reference information to be related back -- to the original file. Note: the reason the line number comes -- first is that a leading digit immediately identifies this as -- a Source_Reference entry, rather than a subunit-name. -- A line number of zero for line: in this entry indicates that -- there is more than one source reference pragma. In this case, -- the line numbers in the cross-reference are correct, and refer -- to the original line number, but there is no information that -- allows a reader of the ALI file to determine the exact mapping -- of physical line numbers back to the original source. -- Files with a zero checksum and a non-zero time stamp are in general -- files on which the compilation depends but which are not Ada files -- with further dependencies. This includes preprocessor data files -- and preprocessor definition files. -- Note: blank lines are ignored when the library information is -- read, and separate sections of the file are separated by blank -- lines to ease readability. Blanks between fields are also -- ignored. -- For entries corresponding to files that were not present (and -- thus resulted in error messages), or for files that are not -- part of the dependency set, both the time stamp and checksum -- are set to all zero characters. These dummy entries are ignored -- by the binder in dependency checking, but must be present for -- proper interpretation of the cross-reference data. -------------------------- -- Cross-Reference Data -- -------------------------- -- The cross-reference data follows the dependency lines. See -- the spec of Lib.Xref for details on the format of this data. ---------------------- -- Global_Variables -- ---------------------- -- The table structure defined here stores one entry for each -- Interrupt_State pragma encountered either in the main source or -- in an ancillary with'ed source. Since interrupt state values -- have to be consistent across all units in a partition, we may -- as well detect inconsistencies at compile time when we can. type Interrupt_State_Entry is record Interrupt_Number : Pos; -- Interrupt number value Interrupt_State : Character; -- Set to r/s/u for Runtime/System/User Pragma_Loc : Source_Ptr; -- Location of pragma setting this value in place end record; package Interrupt_States is new Table.Table ( Table_Component_Type => Interrupt_State_Entry, Table_Index_Type => Nat, Table_Low_Bound => 1, Table_Initial => 30, Table_Increment => 200, Table_Name => "Name_Interrupt_States"); ----------------- -- Subprograms -- ----------------- procedure Ensure_System_Dependency; -- This procedure ensures that a dependency is created on system.ads. -- Even if there is no semantic dependency, Targparm has read the -- file to acquire target parameters, so we need a source dependency. procedure Write_ALI (Object : Boolean); -- This procedure writes the library information for the current main unit -- The Object parameter is true if an object file is created, and false -- otherwise. -- -- Note: in the case where we are not generating code (-gnatc mode), this -- routine only writes an ALI file if it cannot find an existing up to -- date ALI file. If it *can* find an existing up to date ALI file, then -- it reads this file and sets the Lib.Compilation_Arguments table from -- the A lines in this file. procedure Add_Preprocessing_Dependency (S : Source_File_Index); -- Indicate that there is a dependency to be added on a preprocessing -- data file or on a preprocessing definition file. end Lib.Writ;