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3.6.7 Output Section Discarding

The linker will not normally create output sections with no contents. This is for convenience when referring to input sections that may or may not be present in any of the input files. For example:

.foo : { *(.foo) }

will only create a ‘.foo’ section in the output file if there is a ‘.foo’ section in at least one input file, and if the input sections are not all empty. Other link script directives that allocate space in an output section will also create the output section. So too will assignments to dot even if the assignment does not create space, except for ‘. = 0’, ‘. = . + 0’, ‘. = sym’, ‘. = . + sym’ and ‘. = ALIGN (. != 0, expr, 1)’ when ‘sym’ is an absolute symbol of value 0 defined in the script. This allows you to force output of an empty section with ‘. = .’.

The linker will ignore address assignments (see Output Section Address) on discarded output sections, except when the linker script defines symbols in the output section. In that case the linker will obey the address assignments, possibly advancing dot even though the section is discarded.

The special output section name ‘/DISCARD/’ may be used to discard input sections. Any input sections which are assigned to an output section named ‘/DISCARD/’ are not included in the output file.

This can be used to discard input sections marked with the ELF flag SHF_GNU_RETAIN, which would otherwise have been saved from linker garbage collection.

Note, sections that match the ‘/DISCARD/’ output section will be discarded even if they are in an ELF section group which has other members which are not being discarded. This is deliberate. Discarding takes precedence over grouping.

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