This PR is about an assertion failure in GDB that can be triggered by
setting "backtrace limit" to a value that causes GDB to stop unwinding
after an inline frame. In this case, an assertion in
inline_frame_this_id will trigger:
/* We need a valid frame ID, so we need to be based on a valid
frame. (...). */
gdb_assert (frame_id_p (*this_id));
Looking at the function:
static void
inline_frame_this_id (struct frame_info *this_frame,
void **this_cache,
struct frame_id *this_id)
{
struct symbol *func;
/* In order to have a stable frame ID for a given inline function,
we must get the stack / special addresses from the underlying
real frame's this_id method. So we must call get_prev_frame.
Because we are inlined into some function, there must be previous
frames, so this is safe - as long as we're careful not to
create any cycles. */
*this_id = get_frame_id (get_prev_frame (this_frame));
we see we're computing the frame id for the inline frame. If this is
an inline frame, which is a virtual frame constructed based on debug
info, on top of a real stack frame, we should _always_ be able to find
where the frame was inlined into, as that ultimately just means
peeling off the virtual frames on top of the real stack frame. If
there ultimately was no prev (real) stack frame, then we wouldn't have
been able to construct the inline frame either, by design. That's
what the assertion catches.
So we have an inline frame, we should _always_ be able to compute its
ID, even if that means bypassing the user backtrace limits to get at
the real stack frame's info. The problem is that inline_frame_id
calls get_prev_frame, and that takes user backtrace limits into
account. Code that wants to bypass the limits calls get_prev_frame_1
instead.
Note how get_prev_frame_1 already skips all checks for inline frames:
/* If we are unwinding from an inline frame, all of the below tests
were already performed when we unwound from the next non-inline
frame. We must skip them, since we can not get THIS_FRAME's ID
until we have unwound all the way down to the previous non-inline
frame. */
if (get_frame_type (this_frame) == INLINE_FRAME)
return get_prev_frame_if_no_cycle (this_frame);
And note how the related frame_unwind_caller_id function also uses
get_prev_frame_1:
struct frame_id
frame_unwind_caller_id (struct frame_info *next_frame)
{
struct frame_info *this_frame;
/* Use get_prev_frame_1, and not get_prev_frame. The latter will truncate
the frame chain, leading to this function unintentionally
returning a null_frame_id (e.g., when a caller requests the frame
ID of "main()"s caller. */
next_frame = skip_artificial_frames (next_frame);
this_frame = get_prev_frame_1 (next_frame);
if (this_frame)
return get_frame_id (skip_artificial_frames (this_frame));
else
return null_frame_id;
}
get_prev_frame_1 is currently static in frame.c. As a _1 suffix is
not a good name for an extern function, I've renamed it.
Tested on x86-64 Fedora 17.
gdb/
2014-04-18 Pedro alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
PR backtrace/15558
* frame.c (get_prev_frame_1): Rename to ...
(get_prev_frame_always): ... this, and make extern. Adjust.
(skip_artificial_frames): Use get_prev_frame_always.
(frame_unwind_caller_id, frame_pop, get_prev_frame)
(get_frame_unwind_stop_reason): Adjust to rename.
* frame.h (get_prev_frame_always): Declare.
* inline-frame.c: Include frame.h.
(inline_frame_this_id): Use get_prev_frame_always.
gdb/testsuite/
2014-04-18 Tom Tromey <palves@redhat.com>
Pedro alves <tromey@redhat.com>
PR backtrace/15558
* gdb.opt/inline-bt.exp: Test backtracing from an inline function
with a backtrace limit.
* gdb.python/py-frame-inline.exp: Test running to an inline
function with a backtrace limit, and printing the newest frame.
* gdb.python/py-frame-inline.c (main): Call f.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
PR breakpoints/10738
* dwarf2read.c (use_deprecated_index_sections): New global.
(struct partial_die_info): New member may_be_inlined.
(read_partial_die): Set may_be_inlined where appropriate.
(add_partial_subprogram): Add partial symbols for partial
DIEs that may be inlined.
(new_symbol_full): Add inlined subroutines to the current
scope.
(write_psymtabs_to_index): Bump version number.
(dwarf2_read_index): Read only version 6 indices unless
use_deprecated_index_sections is set.
* linespec.c (symbol_and_data_callback): New structure.
(iterate_inline_only): New function.
(iterate_over_all_matching_symtabs): New argument
"include_inline". If nonzero, also call the callback for
symbols representing inlined subroutines.
(lookup_prefix_sym): Pass extra argument to the above.
(find_function_symbols): Likewise.
(add_matching_symbols_to_info): Likewise.
* NEWS: Mention that GDB can now set breakpoints on inlined
functions.
gdb/doc:
PR breakpoints/10738
* gdb.texinfo (Inline Functions): Remove the now-unnecessary @item
stating that GDB cannot set breakpoints on inlined functions.
(Mode Options): Document --use-deprecated-index-sections.
(Index Section Format): Document new index section version format.
gdb/testsuite:
PR breakpoints/10738
* gdb.opt/inline-break.exp: New file.
* gdb.opt/inline-break.c: Likewise.
* gdb.dwarf2/inline-break.exp: Likewise.
* gdb.dwarf2/inline-break.S: Likewise.
* gdb.base/annota1.exp: Cope with old .gdb_index warnings.
* gdb.base/async-shell.exp: Likewise.
* lib/mi-support.exp (library_loaded_re): Likewise.
(func1): Use it.
(func2): Likewise.
(func3): Likewise.
(outer_inline1): Likewise.
(outer_inline2): Likewise.
* gdb.opt/inline-bt.c (ATTR): New define.
(func1): Use it.
(func2): Likewise.
* gdb.opt/inline-locals.c (ATTR): New define.
(func1): Use it.
(func2): Likewise.
* NEWS: Document inlined function support.
* Makefile.in (SFILES): Add inline-frame.c.
(COMMON_OBS): Add inline-frame.o.
* block.c (contained_in): Rewrite to use lexical nesting.
(block_linkage_function): Skip inlined function blocks.
(block_inlined_p): New.
* block.h (struct block): Update comment.
(block_inlined_p): New prototype.
* blockframe.c (get_frame_block): Handle inlined functions.
(get_frame_function): Do not use block_linkage_function.
(block_innermost_frame): Use get_frame_block and contained_in.
* breakpoint.c (watchpoint_check): Remove extra reinit_frame_cache.
Skip over inlined functions. Simplify epilogue check.
(bpstat_check_breakpoint_conditions): Use get_stack_frame_id.
Update comments.
(set_momentary_breakpoint): Only accept non-inlined frames.
(watch_command_1): Use frame_unwind_caller_pc and
frame_unwind_caller_id instead of get_prev_frame.
(until_break_command): Likewise. Use get_stack_frame_id.
* buildsym.c (end_symtab): Set SYMBOL_SYMTAB for block functions.
* dwarf2loc.c (dwarf_expr_frame_base): Use block_linkage_function.
* dwarf2read.c (process_die): Handle DW_TAG_inlined_subroutine.
(read_func_scope, new_symbol): Likewise. Handle arguments specially
for inlined functions without call site information.
(inherit_abstract_dies): Allow tag mismatch for inlined subroutines.
(die_specification): Treat DW_AT_abstract_origin as a specification.
(read_type_die): Handle DW_TAG_inlined_subroutine.
* frame-unwind.c (frame_unwind_init): Add inline_frame_unwind.
* frame.c (fprint_frame_id): Print inline depth.
(fprint_frame_type): Handle INLINE_FRAME and SENTINEL_FRAME.
(skip_inlined_frames, get_stack_frame_id): New.
(frame_unwind_caller_id): Use skip_inlined_frames.
(frame_id_inlined_p): New.
(frame_id_eq): Make the logic match the comments. Add inline_depth
check.
(frame_id_inner): Handle inlined functions.
(frame_unwind_pc): New function, copied from frame_unwind_caller_pc.
(frame_unwind_caller_pc): Use skip_inlined_frames and frame_unwind_pc.
(get_prev_frame_1): Check for inline frames. Split out frame
allocation to get_prev_frame_raw.
(get_prev_frame_raw): New function.
(get_prev_frame): Handle inline frames.
(get_frame_pc): Use frame_unwind_pc.
(get_frame_address_in_block): Skip inlined frames on both sides.
(pc_notcurrent): Delete.
(find_frame_sal): Rewrite to handle inline call sites. Use
get_frame_address_in_block.
(deprecated_update_frame_pc_hack): Make static.
* frame.h: Update comments.
(struct frame_id): Add inline_depth.
(enum frame_type): Add INLINE_FRAME.
(frame_id_inlined_p, get_stack_frame_id): New prototypes.
* gdbthread.h (struct thread_info): Add step_stack_frame_id field.
* infcmd.c (set_step_frame): New function.
(step_once): Use set_step_frame. Handle inlined functions.
(until_next_command): Use set_step_frame.
(finish_backward), finish_forward): Use get_stack_frame_id.
(finish_command): Support inlined functions.
* inferior.h (set_step_info): New prototype.
* infrun.c (RESUME_ALL): Use minus_one_ptid.
(clear_proceed_status): Clear step_stack_frame_id.
(init_wait_for_inferior): Call clear_inline_frame_state.
(init_execution_control_state): Make static.
(set_step_info): New function.
(init_thread_stepping_state): Do not set the symtab or line here.
(stepped_in_from): New function.
(handle_inferior_event): Handle inlined functions. Use set_step_info.
(insert_step_resume_breakpoint_at_frame): Use get_stack_frame_id.
(struct inferior_status): Add step_stack_frame_id.
(save_inferior_status, restore_inferior_status): Save and restore
step_stack_frame_id.
* inline-frame.c, inline-frame.h: New files.
* minsyms.c (prim_record_minimal_symbol_and_info): Use XCALLOC.
* regcache.c (regcache_write_pc): Call reinit_frame_cache.
* s390-tdep.c (s390_prologue_frame_unwind_cache): Handle INLINE_FRAME.
* stack.c (frame_show_address): New.
(print_frame_info, print_frame): Use it.
(find_frame_funname): Use get_frame_function. Handle inlined blocks.
(frame_info): Mark inlined functions.
(backtrace_command_1): Use get_current_user_frame.
(print_frame_local_vars, print_frame_label_vars): Update comments.
(return_command): Refuse inlined functions.
* symtab.c (lookup_symbol_aux_local): Stop at inlined function
boundaries.
(find_function_start_sal): Avoid inlined functions.
(completion_list_add_fields): New function.
(default_make_symbol_completion_list): Use it. Use block_static_block
and block_global_block. Check for inlined functions.
(skip_prologue_using_sal): Avoid line number comparison across
inlining.
* symtab.h (struct symbol): Add is_inlined.
(SYMBOL_INLINED): New.
* target.c (target_resume): Call clear_inline_frame_state.
* valops.c (value_of_variable): Check block_inlined_p.
gdb/doc/
* gdb.texinfo (Debugging Optimized Code): New chapter.
(Compiling for Debugging): Reference it. Move some
text to the new section.
gdb/testsuite/
* gdb.base/break.exp: Add an XFAIL for gcc/36748.
* gdb.cp/annota2.exp: Accept frames-invalid in more places.
* gdb.opt/Makefile.in (EXECUTABLES): Update.
* gdb.opt/clobbered-registers-O2.exp: Update to GPL v3.
* gdb.opt/inline-bt.c, gdb.opt/inline-bt.exp,
gdb.opt/inline-cmds.c, gdb.opt/inline-cmds.exp,
gdb.opt/inline-locals.c, gdb.opt/inline-locals.exp,
gdb.opt/inline-markers.c: New files.
* lib/gdb.exp (skip_inline_frame_tests): New function.
(skip_inline_var_tests): New function.
