sysdeps/generic/unwind-link.h

   1 /* Dynamic loading of the libgcc unwinder.  Generic version.
   2    Copyright (C) 2021-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _UNWIND_LINK_H
  20 #define _UNWIND_LINK_H
  21
  22 #include <unwind.h>
  23 #include <unwind-arch.h>
  24
  25 #if !UNWIND_LINK_FRAME_ADJUSTMENT
  26 static inline void *
  27 unwind_arch_adjustment (void *prev, void *addr)
  28 {
  29   return addr;
  30 }
  31 #endif
  32
  33 #ifdef SHARED
  34 # include <pointer_guard.h>
  35 # include <unwind-resume.h>
  36
  37 # if UNWIND_LINK_FRAME_STATE_FOR
  38 struct frame_state;
  39 # endif
  40
  41 struct unwind_link
  42 {
  43   __typeof (_Unwind_Backtrace) *ptr__Unwind_Backtrace;
  44   __typeof (_Unwind_ForcedUnwind) *ptr__Unwind_ForcedUnwind;
  45   __typeof (_Unwind_GetCFA) *ptr__Unwind_GetCFA;
  46 # if UNWIND_LINK_GETIP
  47   __typeof (_Unwind_GetIP) *ptr__Unwind_GetIP;
  48 # endif
  49   __typeof (_Unwind_Resume) *ptr__Unwind_Resume;
  50 #if UNWIND_LINK_FRAME_STATE_FOR
  51   struct frame_state *(*ptr___frame_state_for) (void *, struct frame_state *);
  52 #endif
  53   _Unwind_Reason_Code (*ptr_personality) PERSONALITY_PROTO;
  54   UNWIND_LINK_EXTRA_FIELDS
  55 };
  56
  57 /* Return a pointer to the implementation, or NULL on failure.  */
  58 struct unwind_link *__libc_unwind_link_get (void);
  59 libc_hidden_proto (__libc_unwind_link_get)
  60
  61 /* UNWIND_LINK_PTR returns the stored function pointer NAME from the
  62    cached unwind link OBJ (which was previously returned by
  63    __libc_unwind_link_get).  */
  64 # define UNWIND_LINK_PTR(obj, name, ...)                             \
  65   ({                                                                \
  66     __typeof ((obj)->ptr_##name) __unwind_fptr = (obj)->ptr_##name; \
  67     PTR_DEMANGLE (__unwind_fptr);                                   \
  68     __unwind_fptr;                                                  \
  69   })
  70
  71 /* Called from fork, in the new subprocess.  */
  72 void __libc_unwind_link_after_fork (void);
  73
  74 /* Called from __libc_freeres.  */
  75 void __libc_unwind_link_freeres (void) attribute_hidden;
  76
  77 #else /* !SHARED */
  78
  79 /* Dummy implementation so that the code can be shared with the SHARED
  80    version.  */
  81 struct unwind_link;
  82 static inline struct unwind_link *
  83 __libc_unwind_link_get (void)
  84 {
  85   /* Return something that is not a null pointer, so that error checks
  86      succeed.  */
  87   return (struct unwind_link *) 1;
  88 }
  89
  90 /* Directly call the static implementation.  */
  91 # define UNWIND_LINK_PTR(obj, name, ...) \
  92   ((void) (obj), &name)
  93
  94 static inline void
  95 __libc_unwind_link_after_fork (void)
  96 {
  97   /* No need to clean up if the unwinder is statically linked.  */
  98 }
  99
 100 #endif /* !SHARED */
 101
 102 #endif /* _UNWIND_LINK_H */