commit gcc-4.4.3 which is used to build gcc-4.4.3 Android toolchain in master.

The source is based on fsf gcc-4.4.3 and contains local patches which
are recorded in gcc-4.4.3/README.google.

Change-Id: Id8c6d6927df274ae9749196a1cc24dbd9abc9887

1 files changed, 753 insertions, 0 deletions

diff --git a/gcc-4.4.3/gcc/ada/lib-writ.ads b/gcc-4.4.3/gcc/ada/lib-writ.ads
new file mode 100644
index 000000000..e0c0f3442
--- /dev/null
+++ b/gcc-4.4.3/gcc/ada/lib-writ.ads
@@ -0,0 +1,753 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT COMPILER COMPONENTS                         --
+--                                                                          --
+--                             L I B . W R I T                              --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--          Copyright (C) 1992-2008, 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 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 such 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 file. 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.
+
+   --  -------------------------------------
+   --  -- S Priority Specific Dispatching --
+   --  -------------------------------------
+
+   --    S policy_identifier first_priority last_priority line-number
+
+   --      This line records information from a Priority_Specific_Dispatching
+   --      pragma. There is one line for each separate pragma, and if no such
+   --      pragmas are used, then no S lines are present.
+
+   --      The policy_identifier is the first character (upper case) of the
+   --      corresponding policy name (e.g. 'F' for FIFO_Within_Priorities).
+
+   --      The first_priority and last_priority fields define the range of
+   --      priorities to which the specified dispatching policy apply.
+
+   --      The line number is an unsigned decimal integer giving the
+   --      line number of the corresponding Priority_Specific_Dispatching
+   --      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:
+   --
+   --         BD  Unit does not have pragma Elaborate_Body, but the elaboration
+   --             circuit has determined that it would be a good idea if this
+   --             pragma were present, since the body of the package contains
+   --             elaboration code that modifies one or more variables in the
+   --             visible part of the package. The binder will try, but does
+   --             not promise, to keep the elaboration of the body close to
+   --             the elaboration of the spec.
+   --
+   --         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, or is a generic instance
+   --             that has a body. Set for instances because RM 12.3(20)
+   --             requires that the body be immediately elaborated after the
+   --             spec (we would normally do that anyway, because elaborate
+   --             spec and body together whenever possible, and for an instance
+   --             it is always possible; however setting EB ensures that this
+   --             is done even when using the -p gnatbind switch).
+   --
+   --         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, or else there
+   --             is at least one use of the Invalid_Value attribute.
+   --
+   --         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.
+   --
+   --         OL   The units in this file are compiled with a local pragma
+   --              Optimize_Alignment, so no consistency requirement applies
+   --              to these units. All internal units have this status since
+   --              they have an automatic default of Optimize_Alignment (Off).
+   --
+   --         OO   Optimize_Alignment (Off) is the default setting for all
+   --              units in this file. All files in the partition that specify
+   --              a default must specify the same default.
+   --
+   --         OS   Optimize_Alignment (Space) is the default setting for all
+   --              units in this file. All files in the partition that specify
+   --              a default must specify the same default.
+   --
+   --         OT   Optimize_Alignment (Time) is the default setting for all
+   --              units in this file. All files in the partition that specify
+   --              a default must specify the same default.
+   --
+   --         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.
+
+   --  In fact W lines include implicit withs ???
+
+   --  -----------------------
+   --  -- 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 appearance 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");
+
+   --  The table structure defined here stores one entry for each
+   --  Priority_Specific_Dispatching pragma encountered either in the main
+   --  source or in an ancillary with'ed source. Since
+   --  have to be consistent across all units in a partition, we may
+   --  as well detect inconsistencies at compile time when we can.
+
+   type Specific_Dispatching_Entry is record
+      Dispatching_Policy : Character;
+      --  First character (upper case) of the corresponding policy name
+
+      First_Priority     : Nat;
+      --  Lower bound of the priority range to which the specified dispatching
+      --  policy applies.
+
+      Last_Priority      : Nat;
+      --  Upper bound of the priority range to which the specified dispatching
+      --  policy applies.
+
+      Pragma_Loc         : Source_Ptr;
+      --  Location of pragma setting this value in place
+   end record;
+
+   package Specific_Dispatching is new Table.Table (
+     Table_Component_Type => Specific_Dispatching_Entry,
+     Table_Index_Type     => Nat,
+     Table_Low_Bound      => 1,
+     Table_Initial        => 10,
+     Table_Increment      => 100,
+     Table_Name           => "Name_Priority_Specific_Dispatching");
+
+   -----------------
+   -- 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;