1 files changed, 97 insertions, 0 deletions
diff --git a/lib/crt/crtbegin.c b/lib/crt/crtbegin.c
new file mode 100644
index 000000000..cfbe5e520
--- /dev/null
+++ b/lib/crt/crtbegin.c
@@ -0,0 +1,97 @@
+//===-- crtbegin.c - Start of constructors and destructors ----------------===//
+//
+// 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 <stddef.h>
+
+__attribute__((visibility("hidden"))) void *__dso_handle = &__dso_handle;
+
+__extension__ static void *__EH_FRAME_LIST__[]
+    __attribute__((section(".eh_frame"), aligned(sizeof(void *)))) = {};
+
+extern void __register_frame_info(const void *, void *) __attribute__((weak));
+extern void *__deregister_frame_info(const void *) __attribute__((weak));
+
+#ifndef CRT_HAS_INITFINI_ARRAY
+typedef void (*fp)(void);
+
+static fp __CTOR_LIST__[]
+    __attribute__((section(".ctors"), aligned(sizeof(fp)))) = {(fp)-1};
+extern fp __CTOR_LIST_END__[];
+#endif
+
+extern void __cxa_finalize(void *) __attribute__((weak));
+
+static void __attribute__((used)) __do_init() {
+  static _Bool __initialized;
+  if (__builtin_expect(__initialized, 0))
+    return;
+  __initialized = 1;
+
+  static struct { void *p[8]; } __object;
+  if (__register_frame_info)
+    __register_frame_info(__EH_FRAME_LIST__, &__object);
+
+#ifndef CRT_HAS_INITFINI_ARRAY
+  const size_t n = __CTOR_LIST_END__ - __CTOR_LIST__ - 1;
+  for (size_t i = n; i >= 1; i--) __CTOR_LIST__[i]();
+#endif
+}
+
+#ifdef CRT_HAS_INITFINI_ARRAY
+__attribute__((section(".init_array"),
+               used)) static void (*__init)(void) = __do_init;
+#else  // CRT_HAS_INITFINI_ARRAY
+#if defined(__i386__) || defined(__x86_64__)
+asm(".pushsection .init,\"ax\",@progbits\n\t"
+    "call " __USER_LABEL_PREFIX__ "__do_init\n\t"
+    ".popsection");
+#elif defined(__arm__)
+asm(".pushsection .init,\"ax\",%progbits\n\t"
+    "bl " __USER_LABEL_PREFIX__ "__do_init\n\t"
+    ".popsection");
+#endif  // CRT_HAS_INITFINI_ARRAY
+#endif
+
+#ifndef CRT_HAS_INITFINI_ARRAY
+static fp __DTOR_LIST__[]
+    __attribute__((section(".dtors"), aligned(sizeof(fp)))) = {(fp)-1};
+extern fp __DTOR_LIST_END__[];
+#endif
+
+static void __attribute__((used)) __do_fini() {
+  static _Bool __finalized;
+  if (__builtin_expect(__finalized, 0))
+    return;
+  __finalized = 1;
+
+  if (__cxa_finalize)
+    __cxa_finalize(__dso_handle);
+
+#ifndef CRT_HAS_INITFINI_ARRAY
+  if (__deregister_frame_info)
+    __deregister_frame_info(__EH_FRAME_LIST__);
+
+  const size_t n = __DTOR_LIST_END__ - __DTOR_LIST__ - 1;
+  for (size_t i = 1; i <= n; i++) __DTOR_LIST__[i]();
+#endif
+}
+
+#ifdef CRT_HAS_INITFINI_ARRAY
+__attribute__((section(".fini_array"),
+               used)) static void (*__fini)(void) = __do_fini;
+#else  // CRT_HAS_INITFINI_ARRAY
+#if defined(__i386__) || defined(__x86_64__)
+asm(".pushsection .fini,\"ax\",@progbits\n\t"
+    "call " __USER_LABEL_PREFIX__ "__do_fini\n\t"
+    ".popsection");
+#elif defined(__arm__)
+asm(".pushsection .fini,\"ax\",%progbits\n\t"
+    "bl " __USER_LABEL_PREFIX__ "__do_fini\n\t"
+    ".popsection");
+#endif
+#endif  // CRT_HAS_INIT_FINI_ARRAY