[binutils-gdb] gdb: fix missing print frame when stepping out of function
Tom de Vries via Gdb-cvs <[email protected]>
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https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=3959bfb8a5238692cd910324383c947194a5cdd6 commit 3959bfb8a5238692cd910324383c947194a5cdd6 Author: Tom de Vries <[email protected]> Date: Tue Apr 14 22:36:09 2026 +0200 gdb: fix missing print frame when stepping out of function Consider test-case gdb.dwarf2/dw2-extend-inline-block.exp, specifically the "contiguous block" prefix part, which can be stepped through like this: ... $ gdb -q outputs/gdb.dwarf2/dw2-extend-inline-block/dw2-extend-inline-block-5 Reading symbols from dw2-extend-inline-block-5... (gdb) start ... snip ... Temporary breakpoint 1, main () at dw2-extend-inline-block.c:35 35 /* main:2 */ (gdb) s 36 /* main:3 */ foo (); /* foo call line */ (gdb) foo () at dw2-extend-inline-block.c:26 26 /* foo:1 */ (gdb) s 27 /* foo:2 */ (gdb) s 28 /* foo:3 */ (gdb) s main () at dw2-extend-inline-block.c:37 37 /* main:4 */ (gdb) ... If we slightly modify the line program: ... DW_LNE_set_address main_4 + DW_LNS_advance_line 1 DW_LNS_copy DW_LNE_set_address main_5 - DW_LNS_advance_line 1 DW_LNS_negate_stmt DW_LNS_copy ... we change the 36/0x401165 entry into a 37/0x401165 entry: ... File name Line number Starting address View Stmt dw2-extend-inline-block.c 34 0x401116 x dw2-extend-inline-block.c 35 0x401129 x dw2-extend-inline-block.c 26 0x401138 x dw2-extend-inline-block.c 27 0x401147 x dw2-extend-inline-block.c 28 0x401156 x dw2-extend-inline-block.c 36 0x401156 -dw2-extend-inline-block.c 36 0x401165 +dw2-extend-inline-block.c 37 0x401165 dw2-extend-inline-block.c 37 0x401174 x dw2-extend-inline-block.c 38 0x401183 x dw2-extend-inline-block.c 39 0x401192 x dw2-extend-inline-block.c 40 0x4011a1 x dw2-extend-inline-block.c - 0x4011b7 ... As it happens, the fix to extend truncated inlined function blocks doesn't work in this case. This is PR gdb/33930. We can work around this by making sure that the inlined function block isn't truncated in the first place: ... - DW_AT_high_pc main_3 addr + DW_AT_high_pc main_4 addr ... But then we still run into PR gdb/33981: the problem that gdb doesn't notify us when stepping out of foo: ... (gdb) step^M 28 /* foo:3 */^M (gdb) step^M 37 /* main:4 */^M (gdb) ... What happens is that the slightly different line program triggers a different stepping path, which includes a case of "stepped to a different frame, but it's not the start of a statement", which refreshes the stepping info and consequently updates tp->control.step_frame_id to the frame id of main. So by the time we're stopped at line 37, and are trying to figure out what to print in print_stop_location, this condition evaluates to true: ... if (tp->control.stop_step && (tp->control.step_frame_id == get_frame_id (get_current_frame ())) && (tp->control.step_start_function == find_symbol_for_pc (tp->stop_pc ()))) ... and we get: ... /* Finished step in same frame and same file, just print source line. */ source_flag = SRC_LINE; ... It's good to realize here that because foo is inlined into main, tp->control.step_start_function is not foo but main, so consequently the step_start_function check (which checks if we are still in the same function) also passes, even though we actually stepped from foo into main. The problem is the use of find_symbol_for_pc, this function deliberately skips over inline frames and returns the symbol for the innermost non-inline frame. It might be tempting to think that we should switch to use find_symbol_for_pc_sect_maybe_inline, which will return the symbol for an inline frame, but this also has problems, specifically, attempting this caused a regression in gdb.opt/inline-cmds.exp. The previous version of this patch, which showed the regression can be found here: https://inbox.sourceware.org/gdb-patches/[email protected] At a given $pc the inferior might be reported as being within an inline frame, or it might be reported as being in the containing non-inline frame. When the user performs a 'step' the step_start_function needs to be set based on the function symbol of the frame the inferior is actually reported in. And we have a function that gives us this information, get_frame_function. So instead of looking up the step_start_function based on the $pc value, set it based on the frame. Test gdb.dwarf2/dw2-extend-inline-block.exp is extended with the additional test case described above. Tested on x86_64-linux. Co-Authored-By: Andrew Burgess <[email protected]> Approved-By: Andrew Burgess <[email protected]> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33930 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33981 Diff: --- gdb/gdbthread.h | 12 +++--- gdb/infcmd.c | 3 +- gdb/infrun.c | 5 +-- .../gdb.dwarf2/dw2-extend-inline-block.exp | 45 ++++++++++++++++++++-- 4 files changed, 51 insertions(+), 14 deletions(-) diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h index 224e6e4b657..c56c4ce4036 100644 --- a/gdb/gdbthread.h +++ b/gdb/gdbthread.h @@ -154,10 +154,10 @@ struct thread_control_state CORE_ADDR step_range_start = 0; /* Inclusive */ CORE_ADDR step_range_end = 0; /* Exclusive */ - /* Set m_step_start_function according to PC. */ - void set_step_start_function (CORE_ADDR pc) + /* Set m_step_start_function according to FRAME. */ + void set_step_start_function (const frame_info_ptr &frame) { - m_step_start_function = find_symbol_for_pc (pc); + m_step_start_function = get_frame_function (frame); } /* Reset m_step_start_function. */ @@ -166,11 +166,11 @@ struct thread_control_state m_step_start_function = nullptr; } - /* Return true if the function symbol for PC matches + /* Return true if the function symbol of FRAME matches m_step_start_function. */ - bool in_step_start_function (CORE_ADDR pc) + bool in_step_start_function (const frame_info_ptr &frame) { - return m_step_start_function == find_symbol_for_pc (pc); + return m_step_start_function == get_frame_function (frame); } /* Return true if m_step_start_function is set. */ diff --git a/gdb/infcmd.c b/gdb/infcmd.c index a1df59e09f2..c0d12be6e4a 100644 --- a/gdb/infcmd.c +++ b/gdb/infcmd.c @@ -898,8 +898,7 @@ set_step_frame (thread_info *tp) symtab_and_line sal = find_frame_sal (frame); set_step_info (tp, frame, sal); - CORE_ADDR pc = get_frame_pc (frame); - tp->control.set_step_start_function (pc); + tp->control.set_step_start_function (frame); } /* Step until outside of current statement. */ diff --git a/gdb/infrun.c b/gdb/infrun.c index becd68a21ad..dea2a2cbd48 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -7871,8 +7871,7 @@ process_event_stop_test (struct execution_control_state *ecs) == ecs->event_thread->control.step_stack_frame_id) && ((ecs->event_thread->control.step_stack_frame_id != outer_frame_id) - || !ecs->event_thread->control.in_step_start_function - (ecs->event_thread->stop_pc ())))) + || !ecs->event_thread->control.in_step_start_function (frame)))) { CORE_ADDR stop_pc = ecs->event_thread->stop_pc (); CORE_ADDR real_stop_pc; @@ -9359,7 +9358,7 @@ print_stop_location (const target_waitstatus &ws) if (tp->control.stop_step && (tp->control.step_frame_id == get_frame_id (get_current_frame ())) - && tp->control.in_step_start_function (tp->stop_pc ())) + && tp->control.in_step_start_function (get_current_frame ())) { symtab_and_line sal = find_frame_sal (get_selected_frame (nullptr)); if (sal.symtab != tp->current_symtab) diff --git a/gdb/testsuite/gdb.dwarf2/dw2-extend-inline-block.exp b/gdb/testsuite/gdb.dwarf2/dw2-extend-inline-block.exp index 9e4798b53f3..481dfbdd134 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-extend-inline-block.exp +++ b/gdb/testsuite/gdb.dwarf2/dw2-extend-inline-block.exp @@ -52,8 +52,11 @@ get_func_info main # Create DWARF for the test. In this case, inline function 'foo' is created # with a contiguous address range that needs extending. -proc build_dwarf_for_contiguous_block { asm_file } { +proc build_dwarf_for_contiguous_block { asm_file {range_correct 0} {variant 0} } { Dwarf::assemble $asm_file { + upvar range_correct range_correct + upvar variant variant + declare_labels lines_table inline_func cu { } { @@ -83,7 +86,11 @@ proc build_dwarf_for_contiguous_block { asm_file } { DW_AT_call_file 1 data1 DW_AT_call_line $::foo_call_line data1 DW_AT_low_pc main_1 addr - DW_AT_high_pc main_3 addr + if {$range_correct} { + DW_AT_high_pc main_4 addr + } else { + DW_AT_high_pc main_3 addr + } } } } @@ -120,10 +127,15 @@ proc build_dwarf_for_contiguous_block { asm_file } { DW_LNS_copy DW_LNE_set_address main_4 + if {$variant == 1} { + DW_LNS_advance_line 1 + } DW_LNS_copy DW_LNE_set_address main_5 - DW_LNS_advance_line 1 + if {$variant == 0} { + DW_LNS_advance_line 1 + } DW_LNS_negate_stmt DW_LNS_copy @@ -146,6 +158,22 @@ proc build_dwarf_for_contiguous_block { asm_file } { } } +# Like build_dwarf_for_contiguous_block, but use a slightly different line +# info by setting variant == 1. +# Use range_correct 1, so we're not testing the fix for PR33930. + +proc build_dwarf_for_contiguous_block_2 { asm_file } { + return [build_dwarf_for_contiguous_block $asm_file 1 1] +} + +# Like build_dwarf_for_contiguous_block, but use a slightly different line +# info by setting variant == 1. +# Use range_correct 0, so we're testing the fix for PR33930. + +proc build_dwarf_for_contiguous_block_3 { asm_file } { + return [build_dwarf_for_contiguous_block $asm_file 0 1] +} + # Assuming GDB is stopped at the entry $pc for 'foo', use 'maint info # blocks' to check the block for 'foo' is correct. This function checks # 'foo' created by 'build_dwarf_for_contiguous_block'. @@ -555,6 +583,12 @@ set test_list \ [list "contiguous block" \ build_dwarf_for_contiguous_block \ check_contiguous_block] \ + [list "contiguous block 2" \ + build_dwarf_for_contiguous_block_2 \ + check_contiguous_block] \ + [list "contiguous block 3" \ + build_dwarf_for_contiguous_block_3 \ + check_contiguous_block] \ ] # Run all the tests. @@ -566,6 +600,11 @@ foreach test_spec $test_list { set build_dwarf_func [lindex $test_spec 1] set check_block_func [lindex $test_spec 2] + if {$build_dwarf_func == "build_dwarf_for_contiguous_block_3"} { + # Work around PR gdb/33930. + continue + } + with_test_prefix $prefix { set asm_file [standard_output_file ${testfile}-${suffix}.S] $build_dwarf_func $asm_file