The SECTIONS command tells the linker how to map input sections
into output sections, and how to place the output sections in memory.
The format of the SECTIONS command is:
SECTIONS
{
sections-command
sections-command
...
}
Each sections-command may of be one of the following:
ENTRY command (see Entry command)
The ENTRY command and symbol assignments are permitted inside the
SECTIONS command for convenience in using the location counter in
those commands. This can also make the linker script easier to
understand because you can use those commands at meaningful points in
the layout of the output file.
Output section descriptions and overlay descriptions are described below.
If you do not use a SECTIONS command in your linker script, the
linker will place each input section into an identically named output
section in the order that the sections are first encountered in the
input files. If all input sections are present in the first file, for
example, the order of sections in the output file will match the order
in the first input file. The first section will be at address zero.