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diff --git a/docs/CommandGuide/llvm-ar.pod b/docs/CommandGuide/llvm-ar.pod deleted file mode 100644 index a8f01b0..0000000 --- a/docs/CommandGuide/llvm-ar.pod +++ /dev/null @@ -1,406 +0,0 @@ -=pod - -=head1 NAME - -llvm-ar - LLVM archiver - -=head1 SYNOPSIS - -B<llvm-ar> [-]{dmpqrtx}[Rabfikouz] [relpos] [count] <archive> [files...] - - -=head1 DESCRIPTION - -The B<llvm-ar> command is similar to the common Unix utility, C<ar>. It -archives 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, -B<llvm-ar> generates a symbol table that makes linking faster because -only the symbol table needs to be consulted, not each individual file member -of the archive. - -The B<llvm-ar> command can be used to I<read> both SVR4 and BSD style archive -files. However, it cannot be used to write them. While the B<llvm-ar> command -produces files that are I<almost> identical to the format used by other C<ar> -implementations, it has two significant departures in order to make the -archive appropriate for LLVM. The first departure is that B<llvm-ar> only -uses BSD4.4 style long path names (stored immediately after the header) and -never contains a string table for long names. The second departure is that the -symbol table is formated for efficient construction of an in-memory data -structure that permits rapid (red-black tree) lookups. Consequently, archives -produced with B<llvm-ar> usually won't be readable or editable with any -C<ar> implementation or useful for linking. Using the C<f> modifier to flatten -file names will make the archive readable by other C<ar> implementations -but not for linking because the symbol table format for LLVM is unique. If an -SVR4 or BSD style archive is used with the C<r> (replace) or C<q> (quick -update) operations, the archive will be reconstructed in LLVM format. This -means that the string table will be dropped (in deference to BSD 4.4 long names) -and an LLVM symbol table will be added (by default). The system symbol table -will be retained. - -Here's where B<llvm-ar> departs from previous C<ar> implementations: - -=over - -=item I<Symbol Table> - -Since B<llvm-ar> is intended to archive bitcode files, the symbol table -won't make much sense to anything but LLVM. Consequently, the symbol table's -format has been simplified. It consists simply of a sequence of pairs -of a file member index number as an LSB 4byte integer and a null-terminated -string. - -=item I<Long Paths> - -Some C<ar> implementations (SVR4) use a separate file member to record long -path names (> 15 characters). B<llvm-ar> takes the BSD 4.4 and Mac OS X -approach which is to simply store the full path name immediately preceding -the data for the file. The path name is null terminated and may contain the -slash (/) character. - -=item I<Compression> - -B<llvm-ar> can compress the members of an archive to save space. The -compression used depends on what's available on the platform and what choices -the LLVM Compressor utility makes. It generally favors bzip2 but will select -between "no compression" or bzip2 depending on what makes sense for the -file's content. - -=item I<Directory Recursion> - -Most C<ar> implementations do not recurse through directories but simply -ignore directories if they are presented to the program in the F<files> -option. B<llvm-ar>, however, can recurse through directory structures and -add all the files under a directory, if requested. - -=item I<TOC Verbose Output> - -When B<llvm-ar> prints out the verbose table of contents (C<tv> option), it -precedes the usual output with a character indicating the basic kind of -content in the file. A blank means the file is a regular file. A 'Z' means -the file is compressed. A 'B' means the file is an LLVM bitcode file. An -'S' means the file is the symbol table. - -=back - -=head1 OPTIONS - -The options to B<llvm-ar> are compatible with other C<ar> implementations. -However, there are a few modifiers (F<zR>) that are not found in other -C<ar>s. The options to B<llvm-ar> specify a single basic operation to -perform on the archive, a variety of modifiers for that operation, the -name of the archive file, and an optional list of file names. These options -are used to determine how B<llvm-ar> should process the archive 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 archive. Typically -archive files end with a C<.a> suffix, but this is not required. Following -the F<archive-name> comes a list of F<files> that indicate the specific members -of the archive to operate on. If the F<files> option is not specified, it -generally means either "none" or "all" members, depending on the operation. - -=head2 Operations - -=over - -=item d - -Delete files from the archive. No modifiers are applicable to this operation. -The F<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 F<files> are specified, the archive is not modified. - -=item m[abi] - -Move files from one location in the archive to another. The F<a>, F<b>, and -F<i> modifiers apply to this operation. The F<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 F<files> are specified, the -archive is not modified. - -=item p[k] - -Print files to the standard output. The F<k> modifier applies to this -operation. This operation simply prints the F<files> indicated to the -standard output. If no F<files> are specified, the entire archive is printed. -Printing bitcode files is ill-advised as they might confuse your terminal -settings. The F<p> operation never modifies the archive. - -=item q[Rfz] - -Quickly append files to the end of the archive. The F<R>, F<f>, and F<z> -modifiers apply to this operation. This operation quickly adds the -F<files> to the archive without checking for duplicates that should be -removed first. If no F<files> are specified, the archive is not modified. -Because of the way that B<llvm-ar> constructs the archive file, its dubious -whether the F<q> operation is any faster than the F<r> operation. - -=item r[Rabfuz] - -Replace or insert file members. The F<R>, F<a>, F<b>, F<f>, F<u>, and F<z> -modifiers apply to this operation. This operation will replace existing -F<files> or insert them at the end of the archive if they do not exist. If no -F<files> are specified, the archive is not modified. - -=item 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 F<v> modifier, -B<llvm-ar> also prints out the file type (B=bitcode, Z=compressed, S=symbol -table, blank=regular file), the permission mode, the owner and group, the -size, and the date. If any F<files> are specified, the listing is only for -those files. If no F<files> are specified, the table of contents for the -whole archive is printed. - -=item x[oP] - -Extract archive members back to files. The F<o> modifier applies to this -operation. This operation retrieves the indicated F<files> from the archive -and writes them back to the operating system's file system. If no -F<files> are specified, the entire archive is extract. - -=back - -=head2 Modifiers (operation specific) - -The modifiers below are specific to certain operations. See the Operations -section (above) to determine which modifiers are applicable to which operations. - -=over - -=item [a] - -When inserting or moving member files, this option specifies the destination of -the new files as being C<a>fter the F<relpos> member. If F<relpos> is not found, -the files are placed at the end of the archive. - -=item [b] - -When inserting or moving member files, this option specifies the destination of -the new files as being C<b>efore the F<relpos> member. If F<relpos> is not -found, the files are placed at the end of the archive. This modifier is -identical to the the F<i> modifier. - -=item [f] - -Normally, B<llvm-ar> stores the full path name to a file as presented to it on -the command line. With this option, truncated (15 characters max) names are -used. This ensures name compatibility with older versions of C<ar> but may also -thwart correct extraction of the files (duplicates may overwrite). If used with -the F<R> option, the directory recursion will be performed but the file names -will all be C<f>lattened to simple file names. - -=item [i] - -A synonym for the F<b> option. - -=item [k] - -Normally, B<llvm-ar> will not print the contents of bitcode files when the -F<p> operation is used. This modifier defeats the default and allows the -bitcode members to be printed. - -=item [N] - -This option is ignored by B<llvm-ar> but provided for compatibility. - -=item [o] - -When extracting files, this option will cause B<llvm-ar> to preserve the -original modification times of the files it writes. - -=item [P] - -use full path names when matching - -=item [R] - -This modifier instructions the F<r> option to recursively process directories. -Without F<R>, directories are ignored and only those F<files> that refer to -files will be added to the archive. When F<R> is used, any directories specified -with F<files> will be scanned (recursively) to find files to be added to the -archive. Any file whose name begins with a dot will not be added. - -=item [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. - -=item [z] - -When inserting or replacing any file in the archive, compress the file first. -This -modifier is safe to use when (previously) compressed bitcode files are added to -the archive; the compressed bitcode files will not be doubly compressed. - -=back - -=head2 Modifiers (generic) - -The modifiers below may be applied to any operation. - -=over - -=item [c] - -For all operations, B<llvm-ar> will always create the archive if it doesn't -exist. Normally, B<llvm-ar> will print a warning message indicating that the -archive is being created. Using this modifier turns off that warning. - -=item [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. Using this modifier is more efficient that using -L<llvm-ranlib|llvm-ranlib> which also creates the symbol table. - -=item [S] - -This modifier is the opposite of the F<s> modifier. It instructs B<llvm-ar> to -not build the symbol table. If both F<s> and F<S> are used, the last modifier to -occur in the options will prevail. - -=item [v] - -This modifier instructs B<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. - -=back - -=head1 STANDARDS - -The B<llvm-ar> utility is intended to provide a superset of the IEEE Std 1003.2 -(POSIX.2) functionality for C<ar>. B<llvm-ar> can read both SVR4 and BSD4.4 (or -Mac OS X) archives. If the C<f> modifier is given to the C<x> or C<r> operations -then B<llvm-ar> will write SVR4 compatible archives. Without this modifier, -B<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. - -=head1 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 C<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 character (0x0A). -Following the magic number, the file is composed of even length members that -begin with an archive header and end with a \n padding 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. - -=over - -=item 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 (/) character, then this field -contains C<#1/nnn> where C<nnn> provides the length of the name and the C<#1/> -is literal. In this case, the actual name of the file is provided in the C<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. - -=item 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 specifications. - -=item 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 systems. On Unix, it is the -same value as the st_uid field of the stat structure returned by the stat(2) -operating system call. - -=item 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 systems. On Unix, it is the -same value as the st_gid field of the stat structure returned by the stat(2) -operating system call. - -=item 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 systems. On Unix, it -is the same value as the st_mode field of the stat structure returned by the -stat(2) operating system call. - -=item size - char[10] - -This field provides the size of the file, in bytes, encoded as a decimal ASCII -string. If the size field is negative (starts with a minus sign, 0x02D), then -the archive member is stored in compressed form. The first byte of the archive -member's data indicates the compression type used. A value of 0 (0x30) indicates -that no compression was used. A value of 2 (0x32) indicates that bzip2 -compression was used. - -=item 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. - -=back - -The LLVM symbol table has the special name "#_LLVM_SYM_TAB_#". It is presumed -that no regular archive member file will want this name. The LLVM symbol table -is simply composed of a sequence of triplets: byte offset, length of symbol, -and the symbol itself. Symbols are not null or newline terminated. Here are -the details on each of these items: - -=over - -=item 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 member. 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. - -=item length - vbr encoded 32-bit integer - -The length item provides the length of the symbol that follows. Like this -I<offset> item, the length is variable bit rate encoded. - -=item symbol - character array - -The symbol item provides the text of the symbol that is associated with the -I<offset>. The symbol is not terminated by any character. Its length is provided -by the I<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. - -=back - -=head1 EXIT STATUS - -If B<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. - -=head1 SEE ALSO - -L<llvm-ranlib|llvm-ranlib>, ar(1) - -=head1 AUTHORS - -Maintained by the LLVM Team (L<http://llvm.org/>). - -=cut |
