This change introduces a few helper variables for dealing with verbose
and silent build modes: `silent`, `verbose`, `q` and `s`.
The `silent` and `verbose` variables are boolean values determining
whether the build system has been configured to run silently or
verbosely respectively (i.e. with `--silent` or `V=1`).
These two modes cannot be used together - if `silent` is truthy then
`verbose` is always falsy. As such:
make --silent V=1
... results in a silent build.
In addition to these boolean variables, we also introduce two new
variables - `s` and `q` - for use in rule recipes to conditionally
suppress the output of commands.
When building silently, `s` expands to a value which disables the
command that follows, and `q` expands to a value which supppresses
echoing of the command:
$(s)echo 'This command is neither echoed nor executed'
$(q)echo 'This command is executed but not echoed'
When building verbosely, `s` expands to a value which disables the
command that follows, and `q` expands to nothing:
$(s)echo 'This command is neither echoed nor executed'
$(q)echo 'This command is executed and echoed'
In all other cases, both `s` and `q` expand to a value which suppresses
echoing of the command that follows:
$(s)echo 'This command is executed but not echoed'
$(q)echo 'This command is executed but not echoed'
The `s` variable is predominantly useful for `echo` commands, where you
always want to suppress echoing of the command itself, whilst `q` is
more useful for all other commands.
Change-Id: I8d8ff6ed714d3cb401946c52955887ed7dca602b
Signed-off-by: Chris Kay <chris.kay@arm.com>
Chris Kay