[libc-commits] [libc] [libc] implement sigsetjmp/siglongjmp for x86-64 (PR #136072)

[Schrodinger ZHU Yifan via libc-commits]

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@@ -0,0 +1,70 @@
+//===-- Implementation of setjmp ------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/setjmp/sigsetjmp.h"
+#include "include/llvm-libc-macros/offsetof-macro.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/setjmp/setjmp_impl.h"
+#include "src/setjmp/sigsetjmp_epilogue.h"
+
+#if !defined(LIBC_TARGET_ARCH_IS_X86)
+#error "Invalid file include"
+#endif
+
+namespace LIBC_NAMESPACE_DECL {
+
+#ifdef __i386__
+[[gnu::naked]]
+LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf buf)) {
+  asm(R"(
+      mov 8(%%esp), %%ecx
+      jecxz .Lnosave
+
+      mov 4(%%esp), %%eax
+      pop %c[retaddr](%%eax)
+      mov %%ebx, %c[extra](%%eax)
+      mov %%eax, %%ebx
+      call %P[setjmp]
+      push %c[retaddr](%%ebx)
+      mov %%ebx,4(%%esp)
+      mov %%eax,8(%%esp)
+      mov %c[extra](%%ebx), %%ebx
+      jmp %P[epilogue]
+      
+.Lnosave:
+      jmp %P[setjmp])" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)),
+      [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp),
+      [epilogue] "i"(sigsetjmp_epilogue)
+      : "eax", "ebx", "ecx");
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SchrodingerZhu wrote:

I think this is guarded by the dependency chain. `libc.src.setjmp.sigsetjmp_epilogue` is implemented for linux only so cmake will not populate this target for other platform.

https://github.com/llvm/llvm-project/pull/136072