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[PULL,16/18] docs/devel: make a statement about includes

Message ID 20230427154510.1791273-17-alex.bennee@linaro.org
State New
Headers show
Series [PULL,01/18] tests/requirements.txt: bump up avocado-framework version to 101.0 | expand

Commit Message

Alex Bennée April 27, 2023, 3:45 p.m. UTC 
While not explicitly disallowing header macro abuse (because that
would make us hypocrites) lets at least address some things to think
about.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230424092249.58552-17-alex.bennee@linaro.org>
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Patch

diff --git a/docs/devel/style.rst b/docs/devel/style.rst
index 68aa776930..5bc6f2f095 100644
--- a/docs/devel/style.rst
+++ b/docs/devel/style.rst
@@ -300,6 +300,20 @@  putting those into qemu/typedefs.h instead of including the header.
 
 Cyclic inclusion is forbidden.
 
+Generative Includes
+-------------------
+
+QEMU makes fairly extensive use of the macro pre-processor to
+instantiate multiple similar functions. While such abuse of the macro
+processor isn't discouraged it can make debugging and code navigation
+harder. You should consider carefully if the same effect can be
+achieved by making it easy for the compiler to constant fold or using
+python scripting to generate grep friendly code.
+
+If you do use template header files they should be named with the
+``.c.inc`` or ``.h.inc`` suffix to make it clear they are being
+included for expansion.
+
 C types
 =======