+ /* Check whether THIS_FRAME is the bottom frame of a virtual tail
+ call frame chain. */
+ if (!cache->checked_tailcall_bottom)
+ {
+ cache->checked_tailcall_bottom = 1;
+ dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
+ (cache->entry_cfa_sp_offset_p
+ ? &cache->entry_cfa_sp_offset : NULL));
+ }
+
+ /* Non-bottom frames of a virtual tail call frames chain use
+ dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
+ them. If dwarf2_tailcall_prev_register_first does not have specific value
+ unwind the register, tail call frames are assumed to have the register set
+ of the top caller. */
+ if (cache->tailcall_cache)
+ {
+ struct value *val;
+
+ val = dwarf2_tailcall_prev_register_first (this_frame,
+ &cache->tailcall_cache,
+ regnum);
+ if (val)
+ return val;
+ }
+