third_party: Add libunwind (#1053)

Added libunwind from LLVM 17.0.6.
The library includes functions required for C++ exception handling.

third_party/libunwind/libunwind_ext.h

@@ -0,0 +1,137 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//
+//  Extensions to libunwind API.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LIBUNWIND_EXT__
+#define __LIBUNWIND_EXT__
+
+#include "third_party/libunwind/config.h"
+#include "third_party/libunwind/include/libunwind.h"
+#include "third_party/libunwind/include/unwind.h"
+
+#define UNW_STEP_SUCCESS 1
+#define UNW_STEP_END     0
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern int __unw_getcontext(unw_context_t *);
+extern int __unw_init_local(unw_cursor_t *, unw_context_t *);
+extern int __unw_step(unw_cursor_t *);
+extern int __unw_get_reg(unw_cursor_t *, unw_regnum_t, unw_word_t *);
+extern int __unw_get_fpreg(unw_cursor_t *, unw_regnum_t, unw_fpreg_t *);
+extern int __unw_set_reg(unw_cursor_t *, unw_regnum_t, unw_word_t);
+extern int __unw_set_fpreg(unw_cursor_t *, unw_regnum_t, unw_fpreg_t);
+extern int __unw_resume(unw_cursor_t *);
+
+#ifdef __arm__
+/* Save VFP registers in FSTMX format (instead of FSTMD). */
+extern void __unw_save_vfp_as_X(unw_cursor_t *);
+#endif
+
+extern const char *__unw_regname(unw_cursor_t *, unw_regnum_t);
+extern int __unw_get_proc_info(unw_cursor_t *, unw_proc_info_t *);
+extern int __unw_is_fpreg(unw_cursor_t *, unw_regnum_t);
+extern int __unw_is_signal_frame(unw_cursor_t *);
+extern int __unw_get_proc_name(unw_cursor_t *, char *, size_t, unw_word_t *);
+
+#if defined(_AIX)
+extern uintptr_t __unw_get_data_rel_base(unw_cursor_t *);
+#endif
+
+// SPI
+extern void __unw_iterate_dwarf_unwind_cache(void (*func)(
+    unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh));
+
+// IPI
+extern void __unw_add_dynamic_fde(unw_word_t fde);
+extern void __unw_remove_dynamic_fde(unw_word_t fde);
+
+extern void __unw_add_dynamic_eh_frame_section(unw_word_t eh_frame_start);
+extern void __unw_remove_dynamic_eh_frame_section(unw_word_t eh_frame_start);
+
+#ifdef __APPLE__
+
+// Holds a description of the object-format-header (if any) and unwind info
+// sections for a given address:
+//
+// * dso_base should point to a header for the JIT'd object containing the
+//   given address. The header's type should match the format type that
+//   libunwind was compiled for (so a mach_header or mach_header_64 on Darwin).
+//   A value of zero indicates that no such header exists.
+//
+// * dwarf_section and dwarf_section_length hold the address range of a DWARF
+//   eh-frame section associated with the given address, if any. If the
+//   dwarf_section_length field is zero it indicates that no such section
+//   exists (and in this case dwarf_section should also be set to zero).
+//
+// * compact_unwind_section and compact_unwind_section_length hold the address
+//   range of a compact-unwind info section associated with the given address,
+//   if any. If the compact_unwind_section_length field is zero it indicates
+//   that no such section exists (and in this case compact_unwind_section
+//   should also be set to zero).
+//
+// See the unw_find_dynamic_unwind_sections type below for more details.
+struct unw_dynamic_unwind_sections {
+  unw_word_t dso_base;
+  unw_word_t dwarf_section;
+  size_t     dwarf_section_length;
+  unw_word_t compact_unwind_section;
+  size_t     compact_unwind_section_length;
+};
+
+// Typedef for unwind-info lookup callbacks. Functions of this type can be
+// registered and deregistered using __unw_add_find_dynamic_unwind_sections
+// and __unw_remove_find_dynamic_unwind_sections respectively.
+//
+// An unwind-info lookup callback should return 1 to indicate that it found
+// unwind-info for the given address, or 0 to indicate that it did not find
+// unwind-info for the given address. If found, the callback should populate
+// some or all of the fields of the info argument (which is guaranteed to be
+// non-null with all fields zero-initialized):
+typedef int (*unw_find_dynamic_unwind_sections)(
+    unw_word_t addr, struct unw_dynamic_unwind_sections *info);
+
+// Register a dynamic unwind-info lookup callback. If libunwind does not find
+// unwind info for a given frame in the executable program or normal dynamic
+// shared objects then it will call all registered dynamic lookup functions
+// in registration order until either one of them returns true, or the end
+// of the list is reached. This lookup will happen before libunwind searches
+// any eh-frames registered via __register_frame or
+// __unw_add_dynamic_eh_frame_section.
+//
+// Returns UNW_ESUCCESS for successful registrations. If the given callback
+// has already been registered then UNW_EINVAL will be returned. If all
+// available callback entries are in use then UNW_ENOMEM will be returned.
+extern int __unw_add_find_dynamic_unwind_sections(
+    unw_find_dynamic_unwind_sections find_dynamic_unwind_sections);
+
+// Deregister a dynacim unwind-info lookup callback.
+//
+// Returns UNW_ESUCCESS for successful deregistrations. If the given callback
+// has already been registered then UNW_EINVAL will be returned.
+extern int __unw_remove_find_dynamic_unwind_sections(
+    unw_find_dynamic_unwind_sections find_dynamic_unwind_sections);
+
+#endif
+
+#if defined(_LIBUNWIND_ARM_EHABI)
+extern const uint32_t* decode_eht_entry(const uint32_t*, size_t*, size_t*);
+extern _Unwind_Reason_Code _Unwind_VRS_Interpret(_Unwind_Context *context,
+                                                 const uint32_t *data,
+                                                 size_t offset, size_t len);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __LIBUNWIND_EXT__