The modifications added by the series "M-profile PACBTI-enablement"
(see 9d6b00511e50a54d2472d11f75f7c0f2b4a98b24) have introduced a couple
of .cfi_* instructions.
Like for e6459123e497409a9e3d845c39829a9602ba55a4, these instructions
create object files which contain .eh_frame sections. However, ARM uses
its own unwind info format, not .eh_frame, which is generated by
ARM-specific directives, not .cfi_*. The .eh_frame sections are useless,
but also not removed by strip and may be harmful with some linker
scripts.
Adding ".cfi_sections .debug_frame" (as in glibc) moves the generated
directives towards .debug_frame instead of .eh_frame. Making them easier
to handle.
* libc/machine/arm/aeabi_memmove-thumb2.S: Use .cfi_sections
.debug_frame.
* libc/machine/arm/aeabi_memset-thumb2.S: Likewise.
* libc/machine/arm/memchr.S: Likewise.
* libc/machine/arm/memcpy-armv7m.S: Likewise.
* libc/machine/arm/setjmp.S: Likewise.
* libc/machine/arm/strlen-armv7.S: Likewise.
* libc/machine/arm/strlen-thumb2-Os.S: Likewise.
The libgloss port has been reaching back into newlib internals for a
single header whose contents have been frozen for almost a decade.
To break this backwards libgloss->newlib dependency, move the acle
header to the srcroot include/ so everyone can use the same copy.
Add function prologue/epilogue to conditionally add BTI landing pads
and/or PAC code generation & authentication instructions depending on
compilation flags.
This patch enables PACBTI for all relevant variants of strlen:
* Newlib for armv8.1-m.main+pacbti
* Newlib for armv8.1-m.main+pacbti+mve
* Newlib-nano
The patch moves the inline ASM thumb2 -Os implementation out into its
own .S file.
Tested by building newlib and comparing libc.a binaries before and
after for all permutations of:
Architectures:
armv4 armv4t armv5 armv5t armv5te armv6 armv6j armv6k
armv6z armv6kz armv6t2 armv6-m armv6s-m armv7 armv7-a
armv7ve armv7-r armv7-m armv7e-m armv8-a iwmmxt iwmmxt2
ISAs:
thumb arm
Optimization Levels:
Os O2
Excluding:
armv6s-m -mthumb
armv6-m -mthumb
armv6zk -mthumb
armv6z -mthumb
armv6k -mthumb
armv6j -mthumb
