libunwind: Added unw_backtrace method

Source: ClickHouse/libunwind@52f0f78#diff-a82fc885e2e4facf4b92d26171c13aa4aa5db296f77e1158ba2f8664e3bd1f5c
Upstream-Status: Pending
Signed-off-by: Khem Raj <[email protected]>

Author: kitaisreal

libunwind/include/libunwind.h

@@ -130,6 +130,7 @@ extern int unw_is_fpreg(unw_cursor_t *, unw_regnum_t) LIBUNWIND_AVAIL;
 extern int unw_is_signal_frame(unw_cursor_t *) LIBUNWIND_AVAIL;
 extern int unw_get_proc_name(unw_cursor_t *, char *, size_t, unw_word_t *) LIBUNWIND_AVAIL;
 //extern int       unw_get_save_loc(unw_cursor_t*, int, unw_save_loc_t*);
+extern int unw_backtrace(void **, int) LIBUNWIND_AVAIL;
 
 extern unw_addr_space_t unw_local_addr_space;
 

libunwind/src/libunwind.cpp

@@ -431,6 +431,26 @@ int __unw_remove_find_dynamic_unwind_sections(
 
 #endif // __APPLE__
 
+int unw_backtrace(void **buffer, int size) {
+  unw_context_t context;
+  unw_cursor_t cursor;
+  if (unw_getcontext(&context) || unw_init_local(&cursor, &context)) {
+    return 0;
+  }
+
+  unw_word_t ip;
+  int current = 0;
+  while (unw_step(&cursor) > 0) {
+    if (current >= size || unw_get_reg(&cursor, UNW_REG_IP, &ip)) {
+      break;
+    }
+
+    buffer[current++] = reinterpret_cast<void *>(static_cast<uintptr_t>(ip));
+  }
+
+  return current;
+}
+
 // Add logging hooks in Debug builds only
 #ifndef NDEBUG
 #include <stdlib.h>