gdb/
Recognize virtual tail call frames.
* Makefile.in (SFILES): Add dwarf2-frame-tailcall.c.
(HFILES_NO_SRCDIR): Add dwarf2-frame-tailcall.h.
(COMMON_OBS): Add dwarf2-frame-tailcall.o.
* dwarf2-frame-tailcall.c: New file.
* dwarf2-frame-tailcall.h: New file.
* dwarf2-frame.c: Include dwarf2-frame-tailcall.h.
(execute_cfa_program): New function comment. Return INSN_PTR. Reset
REGS.PREV only after CIE execution.
(struct dwarf2_frame_cache): New field tailcall_cache.
(dwarf2_frame_cache): New variables entry_pc, entry_cfa_sp_offset,
entry_cfa_sp_offset_p and instr. Execute FDE instructions in two
parts, try to find entry_cfa_sp_offset. Call
dwarf2_tailcall_sniffer_first.
(dwarf2_frame_prev_register): Call dwarf2_tailcall_prev_register_first
when appropriate.
(dwarf2_frame_dealloc_cache): New function.
(dwarf2_frame_sniffer): Preinitialize cache by dwarf2_frame_cache.
(dwarf2_frame_unwind): Install dwarf2_frame_dealloc_cache.
(dwarf2_signal_frame_unwind): Do not install dwarf2_frame_dealloc_cache.
(dwarf2_append_unwinders): Add dwarf2_tailcall_frame_unwind.
(dwarf2_frame_cfa): Support also dwarf2_tailcall_frame_unwind.
* dwarf2loc.c (func_addr_to_tail_call_list)
(tailcall_dump, call_sitep, VEC (call_sitep), chain_candidate)
(call_site_find_chain_1, call_site_find_chain): New.
* dwarf2loc.h (struct call_site_chain): New.
(call_site_find_chain): New declaration.
* frame.c (get_frame_address_in_block): Support also TAILCALL_FRAME.
* frame.h (enum frame_type): New entry TAILCALL_FRAME.
* python/py-frame.c (gdbpy_initialize_frames): Add TAILCALL_FRAME.
* stack.c (frame_info): Support also TAILCALL_FRAME.
gdb/doc/
Recognize virtual tail call frames.
* gdb.texinfo (Optimized Code): Add reference to Tail Call Frames.
(Tail Call Frames): New node.
(Frames In Python): Add gdb.TAILCALL_FRAME.
gdb/testsuite/
Recognize virtual tail call frames.
* gdb.arch/amd64-entry-value.cc (c, a, b, amb_z, amb_y, amb_x, amb)
(amb_b, amb_a): New.
(main): Call a and b.
* gdb.arch/amd64-entry-value.exp (tailcall: breakhere, tailcall: bt)
(tailcall: p i, tailcall: p j, set $sp0=$sp, up, p $sp0 == $sp, frame 3)
(p $sp0 + sizeof (void *) == $sp, ambiguous: breakhere, ambiguous: bt):
New tests.