@samp{--oformat=srec} are equivalent. Unique abbreviations of the names
of multiple-letter options are accepted.
+Note - if the linker is being invoked indirectly, via a compiler driver
+(eg @samp{gcc}) then all the linker command line options should be
+prefixed by @samp{-Wl,} (or whatever is appropriate for the particular
+compiler driver) like this:
+
+@smallexample
+ gcc -Wl,--startgroup foo.o bar.o -Wl,--endgroup
+@end smallexample
+
+This is important, because otherwise the compiler driver program may
+silently drop the linker options, resulting in a bad link.
+
+Here is a table of the generic command line switches accepted by the GNU
+linker:
+
@table @code
@kindex -a@var{keyword}
@item -a@var{keyword}
@kindex --nmagic
@item -n
@itemx --nmagic
-Set the text segment to be read only, and mark the output as
-@code{NMAGIC} if possible.
+Turn off page alignment of sections, and mark the output as
+@code{NMAGIC} if possible.
@kindex -N
@kindex --omagic
the output. This might take significantly longer and therefore probably
should only be enabled for the final binary.
+@kindex -q
+@kindex --emit-relocs
+@cindex retain relocations in final executable
+@item -q
+@itemx --emit-relocs
+Leave relocation sections and contents in fully linked exececutables.
+Post link analysis and optimization tools may need this information in
+order to perform correct modifications of executables. This results
+in larger executables.
+
@cindex partial link
@cindex relocatable output
@kindex -r
trouble). The @samp{--traditional-format} switch tells @code{ld} to not
combine duplicate entries.
+@kindex --section-start @var{sectionname}=@var{org}
+@item --section-start @var{sectionname}=@var{org}
+Locate a section in the output file at the absolute
+address given by @var{org}. You may use this option as many
+times as necessary to locate multiple sections in the command
+line.
+@var{org} must be a single hexadecimal integer;
+for compatibility with other linkers, you may omit the leading
+@samp{0x} usually associated with hexadecimal values. @emph{Note:} there
+should be no white space between @var{sectionname}, the equals
+sign (``@key{=}''), and @var{org}.
+
@kindex -Tbss @var{org}
@kindex -Tdata @var{org}
@kindex -Ttext @var{org}
followed by a series of symbol assignments and output section
descriptions enclosed in curly braces.
-The first line in the above example sets the special symbol @samp{.},
-which is the location counter. If you do not specify the address of an
-output section in some other way (other ways are described later), the
-address is set from the current value of the location counter. The
-location counter is then incremented by the size of the output section.
-
The first line inside the @samp{SECTIONS} command of the above example
sets the value of the special symbol @samp{.}, which is the location
counter. If you do not specify the address of an output section in some
@var{output-section-command}
@var{output-section-command}
@dots{}
- @} [>@var{region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
+ @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
@end group
@end smallexample
match all files except the ones specified in the EXCLUDE_FILE list. For
example:
@smallexample
-(*(EXCLUDE_FILE (*crtend.o, *otherfile.o) .ctors))
+(*(EXCLUDE_FILE (*crtend.o *otherfile.o) .ctors))
@end smallexample
-will cause all .ctors sections from all files except crtend.o and otherfile.o
-to be included.
+will cause all .ctors sections from all files except @file{crtend.o} and
+@file{otherfile.o} to be included.
There are two ways to include more than one section:
@smallexample
true of, for example, S-records, the value will be stored in the
endianness of the first input object file.
+Note - these commands only work inside a section description and not
+between them, so the following will produce an error from the linker:
+@smallexample
+SECTIONS @{@ .text : @{@ *(.text) @}@ LONG(1) .data : @{@ *(.data) @}@ @}@
+@end smallexample
+whereas this will work:
+@smallexample
+SECTIONS @{@ .text : @{@ *(.text) ; LONG(1) @}@ .data : @{@ *(.data) @}@ @}@
+@end smallexample
+
@kindex FILL(@var{expression})
@cindex holes, filling
@cindex unspecified memory
@var{output-section-command}
@var{output-section-command}
@dots{}
- @} [>@var{region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
+ @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
@end group
@end smallexample
We've already described @var{section}, @var{address}, and
@node Output Section LMA
@subsubsection Output section LMA
+@kindex AT>@var{lma_region}
@kindex AT(@var{lma})
@cindex load address
@cindex section load address
The linker will normally set the LMA equal to the VMA. You can change
that by using the @code{AT} keyword. The expression @var{lma} that
-follows the @code{AT} keyword specifies the load address of the section.
+follows the @code{AT} keyword specifies the load address of the
+section. Alternatively, with @samp{AT>@var{lma_region}} expression,
+you may specify a memory region for the section's load address. @xref{MEMORY}.
@cindex ROM initialized data
@cindex initialized data in ROM