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