build: determine toolchain tools dynamically
Since the introduction of the toolchain detection framework into the
build system, we have done determination and identification of the
toolchain(s) used for the build at the initialization of the build
system.
This incurs a large cost to the build every time - for every toolchain
that has been requested by the current makefile, we try to identify each
tool in the list of known tool classes, even if that tool doesn't
actually see any use.
For the clean and check-like targets we worked around this by disabling
most of the toolchains if we detect these targets, but this is
inflexible and not very reliable, and it still means that when building
normal targets we are incurring that cost for all tools whether they are
used or not.
This change instead modifies the toolchain detection framework to only
initialize a tool for a given toolchain when it is first used. This does
mean that we can no longer warn about an incorrectly-configured
toolchain at the beginning of build system invocation, but it has the
advantage of substantially reducing build time and the complexity of
*using* the framework (at the cost of an increase in complexity in the
framework itself).
Change-Id: I7f3d06b2eb58c1b26a846791a13b0037f32c8013
Signed-off-by: Chris Kay <chris.kay@arm.com>
15 files changed