tree d9c2b207ab13a9e987cfa2d66a85ffea13d768b9
parent 907d38bea92050271f9a95b12f89f5a40ec6f46f
author Boyan Karatotev <boyan.karatotev@arm.com> 1669040203 +0000
committer Boyan Karatotev <boyan.karatotev@arm.com> 1669912406 +0000

build: include -Wextra in generic builds

TF-A is more strict with compiler warnings in comparison to other
projects (notably Linux) for security and -Wextra enables a lot of
desirable warnings. This patch enables -Wextra by default (from W=1
previously) and reorganises the warning levels so that they can useful
when enabled and not just a build failure. This will help us move
towards fixing the warnings that are too many to fix at once and
enabling all W={1, 2} warnings.

The warning levels get new meanings:
* W=1: warnings we want the generic build to include but are too time
  consuming to fix at the moment. They re-enable warnings taken out for
  generic builds.
* W=2: warnings we want the generic build to include but cannot be
  enabled due to external libraries.
* W=3: warnings that are informative but not necessary and generally too
  verbose and frequently ignored.

Quality expectations for new contributions mean that generally they
should have no warnings up to W=2. To allow code to be developed with
them in mind, -Werror is disabled when W=x is set. This way enabling
warnings will not just fail the build due to technicalities we have and
contributors will be able to actually see if they get any.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Ieb15ddd635d458a956a34b0f9d0ea2f81b9c0745