llvm-ar-3.5(1)



LLVM-AR(1)                           LLVM                           LLVM-AR(1)

NAME
       llvm-ar - LLVM archiver

SYNOPSIS
       llvm-ar [-]{dmpqrtx}[Rabfikou] [relpos] [count] <archive> [files...]

DESCRIPTION
       The  llvm-ar  command is similar to the common Unix utility, ar. It ar-
       chives several files together into a single file. The intent  for  this
       is to produce archive libraries by LLVM bitcode that can be linked into
       an LLVM program. However, the archive can contain any kind of file.  By
       default,  llvm-ar  generates  a  symbol table that makes linking faster
       because only the symbol table needs to be consulted, not each  individ-
       ual file member of the archive.

       The llvm-ar command can be used to read SVR4, GNU and BSD style archive
       files. However, right now it can only write in the GNU  format.  If  an
       SVR4  or  BSD  style  archive  is used with the r (replace) or q (quick
       update) operations, the archive will be reconstructed in GNU format.

       Here's where llvm-ar departs from previous ar implementations:

       Symbol Table
          Since llvm-ar supports bitcode files. The symbol table it creates is
          in GNU format and includes both native and bitcode files.

       Long Paths
          Currently  llvm-ar  can  read  GNU and BSD long file names, but only
          writes archives with the GNU format.

OPTIONS
       The options to llvm-ar are compatible with  other  ar  implementations.
       However,  there  are a few modifiers (R) that are not found in other ar
       implementations. The options to llvm-ar specify a single  basic  opera-
       tion  to perform on the archive, a variety of modifiers for that opera-
       tion, the name of the archive file, and an optional list of file names.
       These  options are used to determine how llvm-ar should process the ar-
       chive file.

       The Operations and Modifiers are explained in the sections  below.  The
       minimal set of options is at least one operator and the name of the ar-
       chive. Typically archive files end with a .a suffix, but  this  is  not
       required.  Following  the archive-name comes a list of files that indi-
       cate the specific members of the archive to operate on.  If  the  files
       option is not specified, it generally means either "none" or "all" mem-
       bers, depending on the operation.

   Operations
       d
          Delete files from the archive. No modifiers are applicable  to  this
          operation.   The  files  options  specify  which  members  should be
          removed from the archive. It is not an error  if  a  specified  file
          does  not appear in the archive.  If no files are specified, the ar-
          chive is not modified.

       m[abi]
          Move files from one location in the archive to another.  The  a,  b,
          and i modifiers apply to this operation. The files will all be moved
          to the location given by the modifiers. If no  modifiers  are  used,
          the  files  will be moved to the end of the archive. If no files are
          specified, the archive is not modified.

       p
          Print files to the standard output. This operation simply prints the
          files  indicated  to the standard output. If no files are specified,
          the  entire   archive  is  printed.   Printing  bitcode   files   is
          ill-advised  as  they  might  confuse  your terminal settings. The p
          operation never modifies the archive.

       q
          Quickly append files to the end  of  the  archive.   This  operation
          quickly  adds  the  files to the archive without checking for dupli-
          cates that should be removed first. If no files are  specified,  the
          archive is not modified.  Because of the way that llvm-ar constructs
          the archive file, its dubious whether the q operation is any  faster
          than the r operation.

       r[abu]
          Replace  or insert file members. The a, b,  and u modifiers apply to
          this operation. This operation will replace existing files or insert
          them at the end of the archive if they do not exist. If no files are
          specified, the archive is not modified.

       t[v]
          Print the table of contents. Without any modifiers,  this  operation
          just  prints  the  names of the members to the standard output. With
          the v modifier, llvm-ar also prints out the  file  type  (B=bitcode,
          S=symbol  table, blank=regular file), the permission mode, the owner
          and group, the size, and the date. If any files are  specified,  the
          listing  is only for those files. If no files are specified, the ta-
          ble of contents for the whole archive is printed.

       x[oP]
          Extract archive members back to files. The  o  modifier  applies  to
          this  operation.  This  operation retrieves the indicated files from
          the archive and writes them back to the operating system's file sys-
          tem. If no files are specified, the entire archive is extract.

   Modifiers (operation specific)
       The  modifiers below are specific to certain operations. See the Opera-
       tions section (above) to determine which modifiers  are  applicable  to
       which operations.

       [a]
          When  inserting  or  moving  member files, this option specifies the
          destination of the new files as being after the  relpos  member.  If
          relpos is not found, the files are placed at the end of the archive.

       [b]
          When  inserting  or  moving  member files, this option specifies the
          destination of the new files as being before the relpos  member.  If
          relpos is not found, the files are placed at the end of the archive.
          This modifier is identical to the i modifier.

       [i]
          A synonym for the b option.

       [o]
          When extracting files, this option will cause  llvm-ar  to  preserve
          the original modification times of the files it writes.

       [u]
          When  replacing  existing  files  in the archive, only replace those
          files that have a time stamp than the time stamp of  the  member  in
          the archive.

   Modifiers (generic)
       The modifiers below may be applied to any operation.

       [c]
          For  all  operations,  llvm-ar  will always create the archive if it
          doesn't exist. Normally, llvm-ar will print a warning message  indi-
          cating  that the archive is being created. Using this modifier turns
          off that warning.

       [s]
          This modifier requests that an archive index (or  symbol  table)  be
          added  to  the  archive.  This is the default mode of operation. The
          symbol table will contain all the externally visible  functions  and
          global variables defined by all the bitcode files in the archive.

       [S]
          This  modifier  is  the  opposite  of  the  s modifier. It instructs
          llvm-ar to not build the symbol table. If both s and S are used, the
          last modifier to occur in the options will prevail.

       [v]
          This  modifier  instructs  llvm-ar  to  be  verbose about what it is
          doing. Each editing operation taken against the archive will produce
          a line of output saying what is being done.

STANDARDS
       The  llvm-ar  utility is intended to provide a superset of the IEEE Std
       1003.2 (POSIX.2) functionality for ar. llvm-ar can read both  SVR4  and
       BSD4.4 (or Mac OS X) archives. If the f modifier is given to the x or r
       operations then llvm-ar will write SVR4  compatible  archives.  Without
       this  modifier, llvm-ar will write BSD4.4 compatible archives that have
       long names  immediately  after  the  header  and  indicated  using  the
       "#1/ddd" notation for the name in the header.

FILE FORMAT
       The file format for LLVM Archive files is similar to that of BSD 4.4 or
       Mac OSX archive files. In fact, except for the  symbol  table,  the  ar
       commands on those operating systems should be able to read LLVM archive
       files. The details of the file format follow.

       Each archive begins with the archive magic number which  is  the  eight
       printable  characters "!<arch>n" where n represents the newline charac-
       ter (0x0A).  Following the magic number, the file is composed  of  even
       length  members that begin with an archive header and end with a n pad-
       ding character if necessary (to make the length even). Each file member
       is composed of a header (defined below), an optional newline-terminated
       "long file name" and the contents of the file.

       The fields of the header are described in the items below.  All  fields
       of the header contain only ASCII characters, are left justified and are
       right padded with space characters.

       name - char[16]
          This field of the header provides the name of the archive member. If
          the  name is longer than 15 characters or contains a slash (/) char-
          acter, then this field contains #1/nnn where nnn provides the length
          of  the  name and the #1/ is literal.  In this case, the actual name
          of the file is provided in the nnn bytes immediately  following  the
          header.  If  the  name  is  15  characters  or less, it is contained
          directly in this field and terminated with a slash (/) character.

       date - char[12]
          This field provides the date of modification of the file in the form
          of  a  decimal  encoded  number  that provides the number of seconds
          since the epoch (since 00:00:00 Jan 1, 1970)  per  Posix  specifica-
          tions.

       uid - char[6]
          This  field  provides  the  user id of the file encoded as a decimal
          ASCII string.  This field might not make much sense on non-Unix sys-
          tems.  On Unix, it is the same value as the st_uid field of the stat
          structure returned by the stat(2) operating system call.

       gid - char[6]
          This field provides the group id of the file encoded  as  a  decimal
          ASCII string.  This field might not make much sense on non-Unix sys-
          tems. On Unix, it is the same value as the st_gid field of the  stat
          structure returned by the stat(2) operating system call.

       mode - char[8]
          This  field provides the access mode of the file encoded as an octal
          ASCII string. This field might not make much sense on non-Unix  sys-
          tems. On Unix, it is the same value as the st_mode field of the stat
          structure returned by the stat(2) operating system call.

       size - char[10]
          This field provides the size of the file, in  bytes,  encoded  as  a
          decimal ASCII string.

       fmag - char[2]
          This  field  is the archive file member magic number. Its content is
          always the two characters back tick (0x60) and newline (0x0A).  This
          provides some measure utility in identifying archive files that have
          been corrupted.

       offset - vbr encoded 32-bit integer
          The offset item provides the offset into the archive file where  the
          bitcode  member  is  stored  that is associated with the symbol. The
          offset value is 0 based at the start of the first "normal" file mem-
          ber.  To  derive  the actual file offset of the member, you must add
          the number of bytes occupied by the file signature (8 bytes) and the
          symbol  tables. The value of this item is encoded using variable bit
          rate encoding to reduce the size of the symbol table.  Variable  bit
          rate  encoding  uses the high bit (0x80) of each byte to indicate if
          there are more bytes to follow. The remaining 7 bits  in  each  byte
          carry bits from the value. The final byte does not have the high bit
          set.

       length - vbr encoded 32-bit integer
          The length item provides the length of the symbol that follows. Like
          this offset item, the length is variable bit rate encoded.

       symbol - character array
          The  symbol  item provides the text of the symbol that is associated
          with the offset. The symbol is not terminated by any character.  Its
          length  is  provided  by the length field. Note that is allowed (but
          unwise) to use non-printing characters (even 0x00)  in  the  symbol.
          This allows for multiple encodings of symbol names.

EXIT STATUS
       If llvm-ar succeeds, it will exit with 0.  A usage error, results in an
       exit code of 1. A hard (file system typically) error results in an exit
       code of 2. Miscellaneous or unknown errors result in an exit code of 3.

SEE ALSO
       ar(1)

AUTHOR
       Maintained by The LLVM Team (http://llvm.org/).

COPYRIGHT
       2003-2016, LLVM Project

3.5                               2016-10-07                        LLVM-AR(1)

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