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[compiler-rt][libunwind] Support aarch64 without FPU (#111235)

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These two libraries don't build for `-march=armv8-a+nofp
-mabi=aapcs-soft` as a couple of uses of floating point instructions and
registers have crept in.

In libunwind, skip save/restore of FPU registers on targets without them.
In compiler-rt, fall back to the old C implementation of __arm_sc_memset when
the target doesn't have an FPU.

---------

Signed-off-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Keith Packard 2024-11-07 08:32:45 -08:00 committed by GitHub
parent 392807ec3e
commit 5a8956ea8b
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GPG Key ID: B5690EEEBB952194
4 changed files with 18 additions and 5 deletions
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5
compiler-rt/lib/builtins/aarch64/sme-libc-mem-routines.S
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@ -6,8 +6,6 @@
#include "../assembly.h"
#ifdef __aarch64__
#define L(l) .L ## l
//
@ -238,7 +236,8 @@ END_COMPILERRT_OUTLINE_FUNCTION(__arm_sc_memcpy)
DEFINE_COMPILERRT_FUNCTION_ALIAS(__arm_sc_memmove, __arm_sc_memcpy)
// This version uses FP registers. Use this only on targets with them
#if defined(__aarch64__) && __ARM_FP != 0
//
// __arm_sc_memset
//

12
compiler-rt/lib/builtins/aarch64/sme-libc-routines.c
View File

@ -1,5 +1,17 @@
#include <stddef.h>
/* The asm version uses FP registers. Use this on targets without them */
#if __ARM_FP == 0
void *__arm_sc_memset(void *dest, int c, size_t n) __arm_streaming_compatible {
unsigned char *destp = (unsigned char *)dest;
unsigned char c8 = (unsigned char)c;
for (size_t i = 0; i < n; ++i)
destp[i] = c8;
return dest;
}
#endif
const void *__arm_sc_memchr(const void *src, int c,
size_t n) __arm_streaming_compatible {
const unsigned char *srcp = (const unsigned char *)src;

4
libunwind/src/UnwindRegistersRestore.S
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@ -658,7 +658,7 @@ DEFINE_LIBUNWIND_FUNCTION(__libunwind_Registers_arm64_jumpto)
ldp x26,x27, [x0, #0x0D0]
ldp x28,x29, [x0, #0x0E0]
ldr x30, [x0, #0x100] // restore pc into lr
#if defined(__ARM_FP) && __ARM_FP != 0
ldp d0, d1, [x0, #0x110]
ldp d2, d3, [x0, #0x120]
ldp d4, d5, [x0, #0x130]
@ -676,7 +676,7 @@ DEFINE_LIBUNWIND_FUNCTION(__libunwind_Registers_arm64_jumpto)
ldp d28,d29, [x0, #0x1F0]
ldr d30, [x0, #0x200]
ldr d31, [x0, #0x208]
#endif
// Finally, restore sp. This must be done after the last read from the
// context struct, because it is allocated on the stack, and an exception
// could clobber the de-allocated portion of the stack after sp has been

2
libunwind/src/UnwindRegistersSave.S
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@ -746,6 +746,7 @@ DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
str x1, [x0, #0x0F8]
str x30, [x0, #0x100] // store return address as pc
// skip cpsr
#if defined(__ARM_FP) && __ARM_FP != 0
stp d0, d1, [x0, #0x110]
stp d2, d3, [x0, #0x120]
stp d4, d5, [x0, #0x130]
@ -763,6 +764,7 @@ DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
stp d28,d29, [x0, #0x1F0]
str d30, [x0, #0x200]
str d31, [x0, #0x208]
#endif
mov x0, #0 // return UNW_ESUCCESS
ret