Branch: refs/heads/blead
Home: https://github.com/Perl/perl5
Commit: 93fbcb7c716b39ce0574f6e1889e2f7d4d1e938d
https://github.com/Perl/perl5/commit/93fbcb7c716b39ce0574f6e1889e2f7d4d1e938d
Author: Tomasz Konojacki <m...@xenu.pl>
Date: 2025-08-26 (Tue, 26 Aug 2025)
Changed paths:
M locale.c
M perl.c
M pp_ctl.c
M regcomp.c
M toke.c
M util.c
Log Message:
-----------
Make local constant arrays static
Local, non-static constant arrays may get re-initialised at runtime (by
pushing their contents on the stack) every time they are reached. This
somewhat surprising behaviour is caused by the fact that the C standard
requires (almost) every object to have a unique address.
In theory, a compiler may eliminate the re-initialisation, if it can
prove that the address of an array is never examined. However:
1. This often isn't possible to prove. The compiler has no way to know
what will happen to an array pointer once it leaves the compilation
unit.
2. Unlike Clang, GCC and Visual C++ don't even attempt this optimisation
at all. GCC has an open ticket for this:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59863
Making those arrays static avoids the problem, because static arrays are
guaranteed to be initialised only once, prior the to the program
startup.
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