contrib/plugins: Add a plugin to generate basic block vectors

contrib/plugins: Add a plugin to generate basic block vectors

SimPoint is a widely used tool to find the ideal microarchitecture
simulation points so Valgrind[2] and Pin[3] support generating basic
block vectors for use with them. Let's add a corresponding plugin to
QEMU too.

Note that this plugin has a different goal with tests/plugin/bb.c.

This plugin creates a vector for each constant interval instead of
counting the execution of basic blocks for the entire run and able to
describe the change of execution behavior. Its output is also
syntactically simple and better suited for parsing, while the output of
tests/plugin/bb.c is more human-readable.

[1] https://cseweb.ucsd.edu/~calder/simpoint/
[2] https://valgrind.org/docs/manual/bbv-manual.html
[3] https://www.intel.com/content/www/us/en/developer/articles/tool/pin-a-dynamic-binary-instrumentation-tool.html

Signed-off-by: Yotaro Nada <yotaro.nada@gmail.com>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240816-bb-v3-1-b9aa4a5c75c5@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240916085400.1046925-16-alex.bennee@linaro.org>