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[PATCH] Fix a hash lookup problem in xfaces.c
From: |
Zhehao Lin |
Subject: |
[PATCH] Fix a hash lookup problem in xfaces.c |
Date: |
Sat, 1 Jan 2022 17:52:41 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 |
Hello, this patch fixes a problem in the `face_for_font` function in `src/
xfaces.c` where an `unsigned` instead of an `uintptr_t` was used to
store the
computed hash value of the face. If the hash value was too large (>UINT_MAX)
and truncated, the lookup and storing (the latter uses `uintptr_t` as
the rest
of the program does) would happen in different buckets, resulting in
constant
cache misses.
This can cause huge performance impact when `face_for_font' is called really
frequently (for example with ligatures enabled), but for brevity please
allow
me to omit the details here.
Zhehao Lin
0001-src-xfaces.c-Use-uintptr_t-instead-of-unsigned-to-st.patch
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