| 1 | //===-- Implementation of setjmp ------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | // We use naked functions to avoid compiler-generated prologue and epilogue. |
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| 10 | // Despite GCC documentation listing this as an unsupported case for extended |
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| 11 | // asm, the generated code is not wrong as we only pass in constant operands |
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| 12 | // to extended asm. |
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| 13 | // See https://github.com/llvm/llvm-project/issues/137055 for related remarks. |
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| 14 | |
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| 15 | #include "hdr/offsetof_macros.h" |
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| 16 | #include "src/__support/common.h" |
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| 17 | #include "src/__support/macros/config.h" |
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| 18 | #include "src/setjmp/setjmp_impl.h" |
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| 19 | |
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| 20 | #if !defined(LIBC_TARGET_ARCH_IS_X86) |
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| 21 | #error "Invalid file include" |
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| 22 | #endif |
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| 23 | |
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| 24 | namespace LIBC_NAMESPACE_DECL { |
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| 25 | |
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| 26 | #ifdef __i386__ |
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| 27 | [[gnu::naked]] |
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| 28 | LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) { |
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| 29 | asm(R"( |
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| 30 | mov 4(%%esp), %%eax |
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| 31 | |
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| 32 | mov %%ebx, %c[ebx](%%eax) |
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| 33 | mov %%esi, %c[esi](%%eax) |
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| 34 | mov %%edi, %c[edi](%%eax) |
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| 35 | mov %%ebp, %c[ebp](%%eax) |
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| 36 | |
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| 37 | lea 4(%%esp), %%ecx |
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| 38 | mov %%ecx, %c[esp](%%eax) |
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| 39 | |
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| 40 | mov (%%esp), %%ecx |
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| 41 | mov %%ecx, %c[eip](%%eax) |
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| 42 | |
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| 43 | xorl %%eax, %%eax |
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| 44 | retl)" ::[ebx] "i" (offsetof(__jmp_buf, ebx)), |
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| 45 | [esi] "i" (offsetof(__jmp_buf, esi)), [edi] "i" (offsetof(__jmp_buf, edi)), |
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| 46 | [ebp] "i" (offsetof(__jmp_buf, ebp)), [esp] "i" (offsetof(__jmp_buf, esp)), |
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| 47 | [eip] "i" (offsetof(__jmp_buf, eip)) |
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| 48 | : "eax" , "ecx" ); |
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| 49 | } |
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| 50 | #else |
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| 51 | [[gnu::naked]] |
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| 52 | LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) { |
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| 53 | asm(R"( |
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| 54 | mov %%rbx, %c[rbx](%%rdi) |
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| 55 | mov %%rbp, %c[rbp](%%rdi) |
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| 56 | mov %%r12, %c[r12](%%rdi) |
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| 57 | mov %%r13, %c[r13](%%rdi) |
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| 58 | mov %%r14, %c[r14](%%rdi) |
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| 59 | mov %%r15, %c[r15](%%rdi) |
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| 60 | |
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| 61 | lea 8(%%rsp), %%rax |
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| 62 | mov %%rax, %c[rsp](%%rdi) |
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| 63 | |
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| 64 | mov (%%rsp), %%rax |
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| 65 | mov %%rax, %c[rip](%%rdi) |
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| 66 | |
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| 67 | xorl %%eax, %%eax |
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| 68 | retq)" ::[rbx] "i" (offsetof(__jmp_buf, rbx)), |
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| 69 | [rbp] "i" (offsetof(__jmp_buf, rbp)), [r12] "i" (offsetof(__jmp_buf, r12)), |
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| 70 | [r13] "i" (offsetof(__jmp_buf, r13)), [r14] "i" (offsetof(__jmp_buf, r14)), |
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| 71 | [r15] "i" (offsetof(__jmp_buf, r15)), [rsp] "i" (offsetof(__jmp_buf, rsp)), |
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| 72 | [rip] "i" (offsetof(__jmp_buf, rip)) |
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| 73 | : "rax" ); |
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| 74 | } |
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| 75 | #endif |
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| 76 | |
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| 77 | } // namespace LIBC_NAMESPACE_DECL |
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| 78 | |
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