[libc-commits] [libc] 4155503 - [libc] Add a note about using assertions in the libc runtime code.

[Siva Chandra Reddy via libc-commits]

Author: Siva Chandra Reddy
Date: 2023-03-07T10:16:50-08:00
New Revision: 4155503b714bb097ce8cdf3ad03008505210eb08

URL: https://github.com/llvm/llvm-project/commit/4155503b714bb097ce8cdf3ad03008505210eb08
DIFF: https://github.com/llvm/llvm-project/commit/4155503b714bb097ce8cdf3ad03008505210eb08.diff

LOG: [libc] Add a note about using assertions in the libc runtime code.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D145466

Added: 
    

Modified: 
    libc/docs/dev/code_style.rst

Removed: 
    


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diff  --git a/libc/docs/dev/code_style.rst b/libc/docs/dev/code_style.rst
index 48197eee2763..c14786fb8874 100644
--- a/libc/docs/dev/code_style.rst
+++ b/libc/docs/dev/code_style.rst
@@ -102,3 +102,15 @@ followed:
    entrypoint is the only exceptional entrypoint on which other entrypoints
    should explicitly depend on if they set ``errno`` to indicate error
    conditions.
+
+Assertions in libc runtime code
+===============================
+
+The libc developers should, and are encouraged to, use assertions freely in
+the libc runtime code. However, the assertion should be listed via the macro
+``LIBC_ASSERT`` defined in ``src/__support/libc_assert.h``. This macro can be
+used from anywhere in the libc runtime code. Internally, all it does is to
+print the assertion expression and exit. It does not implement the semantics
+of the standard ``assert`` macro. Hence, it can be used from any where in the
+libc runtime code without causing any recursive calls or chicken-and-egg
+situations.