ARM Compiler toolchain Using the Linker - ARM Information Center

4.13 Section alignment with the linker
4.13.1 See also
Image structure and generation
When input sections have been ordered and before the base addresses are fixed, armlink inserts
padding, if required, to force each input section to start at an address that is a multiple of the
input section alignment.
The linker permits ELF program headers and output sections to be aligned on a four-byte
boundary regardless of the maximum alignment of the input sections. This enables armlink to
minimize the amount of padding that it inserts into the image.
If you require strict conformance with the ELF specification then use the --no_legacyalign
option. The linker faults the base address of a region if it is not aligned so padding might be
inserted to ensure compliance. When --no_legacyalign is used the region alignment is the
maximum alignment of any input section contained by the region.
If you are using scatter-loading, you can increase the alignment of a load region or execution
region with the ALIGN attribute. For example, you can change an execution region that is
normally four-byte aligned to be eight-byte aligned. However, you cannot reduce the natural
alignment. For example, you cannot force two-byte alignment on a region that is normally
four-byte aligned.
Tasks
• About creating regions on page boundaries on page 8-54.
Reference
Linker Reference:
• --legacyalign, --no_legacyalign on page 2-95
• Load region attributes on page 4-7
• Execution region attributes on page 4-11
• Example of aligning a base address in execution space but still tightly packed in load
space on page 4-41.
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