syzygy/build/FILTER-FORMAT.TXT

Syzygy Filter File Formats
==========================

It is useful to be able to partially instrument or transform a binary. To do
this the Syzygy toolchain can be provided with a filter (specific to the binary
image being modified) specifying which regions of the image should not be
transformed or instrumented.

Filters as passed to the toolchain must be in JSON format, consisting of a
collection of relative addresses and lengths into the image as well as a
signature of the image to ensure the filter is applied to the right image. These
JSON encoded filters are not portable across different versions of the same
image.

The genfilter.exe tool is used to build filters from a textual description,
which is portable across versions of a binary. It uses debug information to
convert textual descriptions of symbols to be filtered into relative addresses
and lengths in the final image.

See 'FILTER-SAMPLE.TXT' and 'FILTER-SAMPLE.JSON' for examples of these formats.