2L(10.1) 2L(10.1)
NAME
0l, 1l, 2l, 5l, 6l, 7l, 8l, kl, ql, vl - loaders
SYNOPSIS
2l [ option ... ] [ file ... ]
etc.
DESCRIPTION
These commands load the named files into executable files
for the corresponding architectures; see 2c(10.1) for the
correspondence between an architecture and the character (1,
2, etc.) that specifies it. The files should be object
files or libraries (archives of object files) for the appro-
priate architecture. Also, a name like -lext represents the
library libext.a in /$objtype/lib, where objtype is one of
68000, etc. as listed in 2c(10.1). The libraries must have
tables of contents (see iar(10.1)).
In practice, -l options are rarely necessary as the header
files for the libraries cause their archives to be included
automatically in the load (see 2c(10.1)). For example, any
program that includes header file libc.h causes the loader
to search the C library /$objtype/lib/libc.a. Also, the
loader creates an undefined symbol _main (or _mainp if pro-
filing is enabled) to force loading of the startup linkage
from the C library.
The order of search to resolve undefined symbols is to load
all files and libraries mentioned explicitly on the command
line, and then to resolve remaining symbols by searching in
topological order libraries mentioned in header files
included by files already loaded. When scanning such
libraries, the algorithm is to scan each library repeatedly
until no new undefined symbols are picked up, then to start
on the next library. Thus if library A needs B which needs
A again, it may be necessary to mention A explicitly so it
will be read a second time.
The loader options are:
-l (As a bare option.) Suppress the default loading
of the startup linkage and libraries specified by
header files.
-o out Place output in file out. Default is O.out, where
O is the first letter of the loader name.
-p Insert profiling code into the executable output;
no special action is needed during compilation or
assembly.
Page 1 Plan 9 (printed 12/21/24)
2L(10.1) 2L(10.1)
-s Strip the symbol tables from the output file.
-a Print the object code in assembly language, with
addresses.
-v Print debugging output that annotates the activi-
ties of the load.
-M (kl only) Generate instructions rather than calls
to emulation routines for multiply and divide.
-Esymbol The entry point for the binary is symbol (default
_main; _mainp under -p).
-x [ file ] Produce an export table in the exe-
cutable. The optional file restricts the exported
symbols to those listed in the file. See
dynld(10.2).
-u [ file ] Produce an export table, import table and
a dynamic load section in the executable. The
optional file restricts the imported symbols to
those listed in the file. See dynld(10.2).
-Hn Executable header is type n. The meaning of the
types is architecture-dependent; typically type 1
is Plan 9 boot format and type 2 is the regular
Plan 9 format, the default. These are reversed on
the MIPS. The Next boot format is 3. Type 4 in
vl creates a MIPS executable for an SGI Unix sys-
tem.
-Tt The text segment starts at address t.
-Dd The data segment starts at address d.
-Rr The text segment is rounded to a multiple of r (if
r is nonzero).
The numbers in the above options can begin with `0x' or `0'
to change the default base from decimal to hexadecimal or
octal. The defaults for the values depend on the compiler
and the header type.
The loaded image has several symbols inserted by the loader:
etext is the address of the end of the text segment; bdata
is the address of the beginning of the data segment; edata
is the address of the end of the data segment; and end is
the address of the end of the bss segment, and of the pro-
gram.
FILES
Page 2 Plan 9 (printed 12/21/24)
2L(10.1) 2L(10.1)
/$objtype/lib for -llib arguments.
SOURCE
/utils/2l etc.
SEE ALSO
2c(10.1), 2a(10.1), iar(10.1), inm(10.1)
Rob Pike, ``How to Use the Plan 9 C Compiler''
Page 3 Plan 9 (printed 12/21/24)