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| 1 | +//===-- Implementation of sigsetjmp ---------------------------------------===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | + |
| 9 | +#include "src/setjmp/sigsetjmp.h" |
| 10 | +#include "hdr/offsetof_macros.h" |
| 11 | +#include "src/__support/common.h" |
| 12 | +#include "src/__support/macros/config.h" |
| 13 | +#include "src/setjmp/setjmp_impl.h" |
| 14 | +#include "src/setjmp/sigsetjmp_epilogue.h" |
| 15 | + |
| 16 | +namespace LIBC_NAMESPACE_DECL { |
| 17 | +[[gnu::naked]] |
| 18 | +LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf buf)) { |
| 19 | +#if defined(__thumb__) && __ARM_ARCH_ISA_THUMB == 1 |
| 20 | + // Thumb1 does not support the high registers > r7 in stmia, so move them |
| 21 | + // into lower GPRs first. |
| 22 | + asm(R"( |
| 23 | + tst r1, r1 |
| 24 | + bne .Ldosave |
| 25 | + b %c[setjmp] |
| 26 | +.Ldosave: |
| 27 | + str r4, [r0, #%c[extra]] |
| 28 | + mov r4, lr |
| 29 | + str r4, [r0, #%c[retaddr]] |
| 30 | + mov r4, r0 |
| 31 | + bl %c[setjmp] |
| 32 | + mov r1, r0 |
| 33 | + mov r0, r4 |
| 34 | + ldr r4, [r0, #%c[retaddr]] |
| 35 | + mov lr, r4 |
| 36 | + ldr r4, [r0, #%c[extra]] |
| 37 | + b %c[epilogue] |
| 38 | + )" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)), |
| 39 | + [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp), |
| 40 | + [epilogue] "i"(sigsetjmp_epilogue) |
| 41 | + : "r0", "r1", "r4"); |
| 42 | +#else |
| 43 | + // Some thumb2 linkers do not support conditional branch to PLT. |
| 44 | + // We branch to local labels instead. |
| 45 | + asm(R"( |
| 46 | + tst r1, r1 |
| 47 | + bne .Ldosave |
| 48 | + b %c[setjmp] |
| 49 | +.Ldosave: |
| 50 | + str r4, [r0, #%c[extra]] |
| 51 | + str lr, [r0, #%c[retaddr]] |
| 52 | + mov r4, r0 |
| 53 | + bl %c[setjmp] |
| 54 | + mov r1, r0 |
| 55 | + mov r0, r4 |
| 56 | + ldr lr, [r0, #%c[retaddr]] |
| 57 | + ldr r4, [r0, #%c[extra]] |
| 58 | + b %c[epilogue] |
| 59 | + )" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)), |
| 60 | + [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "X"(setjmp), |
| 61 | + [epilogue] "X"(sigsetjmp_epilogue) |
| 62 | + : "r0", "r1", "r4"); |
| 63 | +#endif |
| 64 | +} |
| 65 | +} // namespace LIBC_NAMESPACE_DECL |
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