CVS commit: src

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sat May  3 19:57:13 UTC 2025

Modified Files:
        src/lib/libc/arch/arm/gen: _setjmp.S setjmp.S
        src/lib/libc/arch/arm/sys: cerror.S ptrace.S sbrk.S
        src/sys/arch/arm/include: asm.h

Log Message:
arm: Nix most __PIC__ conditionals in .S files.

New macros PCREL_GET(rN,label,pclabel) and PCREL_SYM(label,pclabel)
to enable this by the pattern:

        ldr     rN, label
#ifdef __PIC__
pclabel:
        add     rN, rN, pc
#endif
...
label:
#ifdef __PIC__
        .word   (label - (pclabel + 2*sizeof(instruction)))
#else
        .word   label
#endif

(sizeof(instruction) = 2 for thumb, 4 for non-thumb.)

No binary change in libc with MKPIE=no (i.e., testing both for
changes to the PIC build and changes to the non-PIC build).

In principle, assembly routines could improve instruction scheduling
by splitting up the ldr and add instructions.  But in practice, the
maintenance and auditing burden likely makes this worthwhile by
improving legibility vs a tangle of in-line #ifdefs.

brk.S does things a little differently making it harder to unify.
Could redo it but I don't want to make changes without testing them
first.

PR lib/59391: unnecessary __PIC__ conditionals clutter .S files


To generate a diff of this commit:
cvs rdiff -u -r1.17 -r1.18 src/lib/libc/arch/arm/gen/_setjmp.S
cvs rdiff -u -r1.19 -r1.20 src/lib/libc/arch/arm/gen/setjmp.S
cvs rdiff -u -r1.13 -r1.14 src/lib/libc/arch/arm/sys/cerror.S
cvs rdiff -u -r1.12 -r1.13 src/lib/libc/arch/arm/sys/ptrace.S \
    src/lib/libc/arch/arm/sys/sbrk.S
cvs rdiff -u -r1.35 -r1.36 src/sys/arch/arm/include/asm.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.