SLD

Section: User Commands (1)
Updated: 14 April 1987
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NAME

sld - SPUR link editor

SYNOPSIS

sld [ -A basefile ] [ -d ] [ -e entry ] [ -j ] [ -lx ]
      [ -Ldir ] [ -N ] [ -o name ] [ -p[d] ] [ -pt ] [ -r ] [ -s ] [ -S ]
      [ -T[text] hex ] [ -Tdata hex ] [ -Tsdata hex ]
      [ -u name ] [ -w ] [ -x ] [ -X ] [ -ysym ] [ -z ]
      file ...

DESCRIPTION

sld combines several object programs into one, resolves external references, and searches libraries. In the simplest case several object files are given, and sld combines them, producing an object module which can be either executed or become the input for a further sld run. In the latter case, the -r option must be given to preserve the relocation bits. The output of sld is left on a file called a.out if not otherwise specified by the -o option. The output file is made executable only if no errors occurred during the load, and the -N and -r options were not specified.

The argument files are concatenated in the order specified. The entry point of the output is the beginning of the text unless the -e option is specified.

If any file is a library, it is searched exactly once at the point it is encountered in the argument list. Only those routines defining an unresolved external reference are loaded. The library must have been processed by ranlib(1); its first member must be a file named `__.SYMDEF', which is the dictionary for the library. The dictionary is searched iteratively to satisfy as many references as possible.

The symbols _etext, _edata, _end, _bpdata, and _bpbss (etext, edata, end, bpdata, and bpbss in C) are reserved, and if referred to, are set to the first location above the program, the first location above initialized shared data, and the first location above all shared data, the beginning of private initialized data, and the beginning of uninitialized private data, respectively. It is erroneous to define these symbols.

OPTIONS

Options should appear before the file names, except abbreviated library names specified by the -l option which can appear anywhere.

-A name: Incremental loading: the resulting object may be read into an already executing program. name is the name of a file that supplies the initial symbol table for the resulting object file. Only newly linked material is entered into the text and data portions of a.out, but the new symbol table will reflect all symbols defined before and after the incremental load. This argument must appear before any other object file in the argument list. One or more of the -T options may be used as well, and will be taken to mean that the newly linked segments will commence at the corresponding addresses (which must divisible by 8). By default, text and private data are concatenated. The default starting point for text is the old value of _end. The default starting point for shared data is the old value of _edata_s. The values of _etext, etc., are the same for the resulting object file as they were for name.
-d: Force definition of common storage even if the -r flag is present.
-e entry: Define the entry point: entry argument is the name of the entry point of the loaded program.
-j: Join private data to the end of text. This is the default for the -N option. The switch is ignored if overridden by the -Tdata or -pd options.
-lx: This option is an abbreviation for the library name `dir/libx.a'. Here, x is a string. Dir is one of the directories listed in preceding -L options, or, if no such file exists, then one of the directories `/lib', `/lib/local', or `/usr/local/lib' (tried in that order). A library is searched when its name is encountered, so the placement of a -l is significant.
-Ldir: See -l above.
-N: Do not make the text portion read only or sharable. The data portion immediately follows the text, which is relocated to begin at address 0 (i.e., not preceded by the header). (Use `magic number' 0507.)
-o name: Name is the name of the sld output file, instead of a.out.
-p[d]: `Publicize' private data segment. The initialized private data in each object file is concatenated to the front of the initialized shareable data of that file, and relocated as shareable data. Likewise, the uninitialized private data is concatenated to the front of the uninitialized shared data. The -Tdata option, if present, is ignored. The -Tsdata option is honored, and governs the position of the combined segment. The names _edata and _end (edata and end in C) are set to the values of _edata_s and _end_s, respectively.
-pt: Publicize text segment. The text segments of the object files are concatenated together at the from of the initialized shareable data of that file, and relocated as shareable data. The -Ttext option, if present, only affects the placement of private data (when this follows the text segment), and has no effect on the placement of text. The -Tsdata option is honored, and governs the position of the combined segment.
-r: Generate relocation bits in the output file so that it can be the subject of another sld run. This flag also prevents final definitions from being given to common symbols, and suppresses the `undefined symbol' diagnostics. It implies the -N option.
-s: Strip the output, that is, remove the symbol table and relocation bits to save space (but impair the usefulness of the debuggers). This information can also be removed by strip(1).
-S: Strip the output by removing all symbols except locals and globals.
-T[text] hex: Relocate as if the text (i.e., exclusive of the header) started at address hex (a hexadecimal number, possibly with preceding `0x'). This does not affect where the text is actually loaded; loading the file in the usual way will place the text segment at its standard location, relocated as if it were at address hex.
-Tdatahex: Relocate the private data segment as if it started at location hex (a hexadecimal number as above). Again, this does not affect where the private data segments are actually loaded.
-Tsdatahex: Relocate the shared data segment as if it started at location hex (a hexadecimal number as above). This does not affect where the shared data segments are actually loaded.
-u name: Enter name as an undefined symbol. This is useful for loading wholly from a library, since initially the symbol table is empty and an unresolved reference is needed to force the loading of the first routine.
-w: Each time an object file is automatically included from a library, indicate the name of the object file and a symbol that caused it to be loaded.
-x: Do not preserve local (non-.globl) symbols in the output symbol table; only enter external symbols. This option saves some space in the output file.
-X: Save local symbols except for those whose names begin with `L'. This option is used by cc(1) to discard internally-generated labels while retaining symbols local to routines.
-ysym: Display each file in which sym appears, its type and whether the file defines or references it. Many such options may be given to trace many symbols. It is usually necessary to begin sym with an `_', as external C, FORTRAN and Pascal variables begin with underscores.
-z: Arrange for the process to be loaded on demand from the resulting executable file (0513 `magic number') rather than preloaded. This is the default (and is present here only for compatibility). In the resulting object file, the sizes of the text segment and initialized data segments are multiples of the page size (padded with nulls, if necessary). When loaded in the usual way, they all start on page boundaries, allowing easy demand loading from the object file. The header is incorporated in the first page of text. With this format the first few BSS segment symbols may actually end up in the initialized data segment, and likewise for SBSS segment symbols and the shared data segment; this is to avoid wasting the space resulting from rounding up the data segment sizes.

FILES

/lib/lib*.a            libraries

/usr/lib/lib*.a       more libraries

/usr/local/lib/lib*.a still more libraries

a.out                 output file

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