diff options
Diffstat (limited to 'ld/ld.texinfo')
| -rw-r--r-- | ld/ld.texinfo | 81 |
1 files changed, 71 insertions, 10 deletions
diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 027f196..115f7a2 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -179,18 +179,21 @@ result of linking the file @code{/lib/crt0.o} with @code{hello.o} and the library @code{libc.a}, which will come from the standard search directories. (See the discussion of the @samp{-l} option below.) -The command-line options to @code{ld} may be specified in any order, and -may be repeated at will. Repeating most options with a different -argument will either have no further effect, or override prior +Some of the command-line options to @code{ld} may be specified at any +point in the command line. However, options which refer to files, such +as @samp{-l} or @samp{-T}, cause the file to be read at the point at +which the option appears in the command line, relative to the object +files and other file options. Repeating non-file options with a +different argument will either have no further effect, or override prior occurrences (those further to the left on the command line) of that option. Options which may be meaningfully specified more than once are noted in the descriptions below. @cindex object files -Non-option arguments are objects files which are to be linked together. -They may follow, precede, or be mixed in with command-line options, -except that an object file argument may not be placed between an option -and its argument. +Non-option arguments are object files or archives which are to be linked +together. They may follow, precede, or be mixed in with command-line +options, except that an object file argument may not be placed between +an option and its argument. Usually the linker is invoked with at least one object file, but you can specify other forms of binary input files using @samp{-l}, @samp{-R}, @@ -401,6 +404,14 @@ purpose: the @code{-b}, @code{--format}, @code{--oformat} options, the environment variable. The @sc{gnu} linker will ignore the @code{-F} option when not creating an ELF shared object. +@cindex finalization function +@kindex -fini +@item -fini @var{name} +When creating an ELF executable or shared object, call NAME when the +executable or shared object is unloaded, by setting DT_FINI to the +address of the function. By default, the linker uses @code{_fini} as +the function to call. + @kindex -g @item -g Ignored. Provided for compatibility with other tools. @@ -431,6 +442,14 @@ field rather than the using the file name given to the linker. @item -i Perform an incremental link (same as option @samp{-r}). +@cindex initialization function +@kindex -init +@item -init @var{name} +When creating an ELF executable or shared object, call NAME when the +executable or shared object is loaded, by setting DT_INIT to the address +of the function. By default, the linker uses @code{_init} as the +function to call. + @cindex archive files, from cmd line @kindex -l@var{archive} @kindex --library=@var{archive} @@ -754,7 +773,7 @@ platforms which support shared libraries. @kindex --check-sections @kindex --no-check-sections @item --check-sections -@item --no-check-sections +@itemx --no-check-sections Asks the linker @emph{not} to check section addresses after they have been assigned to see if there any overlaps. Normally the linker will perform this check, and if it finds any overlaps it will produce @@ -1115,7 +1134,7 @@ for compatibility with other linkers, you may omit the leading @kindex --verbose @cindex verbose @item --dll-verbose -@item --verbose +@itemx --verbose Display the version number for @code{ld} and list the linker emulations supported. Display which input files can and cannot be opened. Display the linker script if using a default builtin script. @@ -3407,6 +3426,39 @@ followed by a 1000 byte gap. Then the @samp{.text} section from @samp{.text} section from @file{file3}. The notation @samp{= 0x1234} specifies what data to write in the gaps (@pxref{Output Section Fill}). +@cindex dot inside sections +Note: @code{.} actually refers to the byte offset from the start of the +current containing object. Normally this is the @code{SECTIONS} +statement, whoes start address is 0, hence @code{.} can be used as an +absolute address. If @code{.} is used inside a section description +however, it refers to the byte offset from the start of that section, +not an absolute address. Thus in a script like this: + +@smallexample +SECTIONS +@{ + . = 0x100 + .text: @{ + *(.text) + . = 0x200 + @} + . = 0x500 + .data: @{ + *(.data) + . += 0x600 + @} +@} +@end smallexample + +The @samp{.text} section will be assigned a starting address of 0x100 +and a size of exactly 0x200 bytes, even if there is not enough data in +the @samp{.text} input sections to fill this area. (If there is too +much data, an error will be produced because this would be an attempt to +move @code{.} backwards). The @samp{.data} section will start at 0x500 +and it will have an extra 0x600 bytes worth of space after the end of +the values from the @samp{.data} input sections and before the end of +the @samp{.data} output section itself. + @need 2000 @node Operators @subsection Operators @@ -3876,7 +3928,7 @@ not itself call any subroutines). @section @code{ld}'s support for interworking between ARM and Thumb code @cindex ARM interworking support -@cindex --support-old-code +@kindex --support-old-code For the ARM, @code{ld} will generate code stubs to allow functions calls betweem ARM and Thumb code. These stubs only work with code that has been compiled and assembled with the @samp{-mthumb-interwork} command @@ -3888,6 +3940,15 @@ which will work with non-interworking aware ARM code. Note, however, the linker does not support generating stubs for function calls to non-interworking aware Thumb code. +@cindex thumb entry point +@cindex entry point, thumb +@kindex --thumb-entry=@var{entry} +The @samp{--thumb-entry} switch is a duplicate of the generic +@samp{--entry} switch, in that it sets the program's starting address. +But it also sets the bottom bit of the address, so that it can be +branched to using a BX instruction, and the program will start +executing in Thumb mode straight away. + @ifclear GENERIC @lowersections @end ifclear |