Date: Thu, 18 Jul 2013 22:17:26 -0400 From: Rich Felker <dalias@...ifal.cx> To: musl@...ts.openwall.com Subject: New "portable" crt1.c Hi all, I've been experimenting with an idea for eliminating most of the asm from the "crt" start files. The basic concept is to have a tiny file-scope __asm__ statement, pulled in from arch/$(ARCH)/crt1.h or similar, which does nothing but calling a portable C version of _start, contained in crt1.c, with the right arguments. The benefits: - We get regular (crt1.o) and PIE (Scrt1.o) versions for free. - Porting to new archs is simpler. - Applying the same technique to crti.o/crtn.o, we can support the new-style init_array/fini_array on all archs without lots of new per-arch asm. Attached is a demo for i386 showing how well this approach works (size increase is less than 16 bytes). I'm open to comments, but my feeling is that we should keep the existing crt asm for archs where it already exists, but replace the empty crt1.c with a version based on this approach, and encourage using the new approach on all new ports. In the future, if maintaining the current asm becomes a burden (e.g. if new requirements are introduced) we could remove the existing asm and switch to the C for all ports. Rich View attachment "newcrt.c" of type "text/plain" (622 bytes)
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