armlink gathers information about the content of data sections before choosing the most appropriate compression algorithm to generate the smallest image. If compression is appropriate, the linker can only use one data compressor for all the compressible data sections in the image. Different compression algorithms might be tried on these sections to produce the best overall size. Compression is applied automatically if:
Compressed data size + Size of decompressor < Uncompressed data size
When a compressor has been chosen, armlink adds the decompressor to the code area of your image. If the final image does not contain any compressed data, no decompressor is added.