From 5ce0145de764dc9c6e92daf2f843fa6e496c49d0 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Tue, 17 Dec 2013 20:47:36 +0000 Subject: "tfind" across unavailable-stack frames. Like when stepping, the current stack frame location is expected to be printed as result of tfind command, if that results in moving to a different function. In tfind_1 we see: if (from_tty && (has_stack_frames () || traceframe_number >= 0)) { enum print_what print_what; /* NOTE: in imitation of the step command, try to determine whether we have made a transition from one function to another. If so, we'll print the "stack frame" (ie. the new function and it's arguments) -- otherwise we'll just show the new source line. */ if (frame_id_eq (old_frame_id, get_frame_id (get_current_frame ()))) print_what = SRC_LINE; else print_what = SRC_AND_LOC; print_stack_frame (get_selected_frame (NULL), 1, print_what, 1); do_displays (); } However, when we haven't collected any registers in the tracepoint (collect $regs), that doesn't actually work: (gdb) tstart (gdb) info tracepoints Num Type Disp Enb Address What 1 tracepoint keep y 0x080483b7 in func0 at ../.././../git/gdb/testsuite/gdb.trace/circ.c:28 collect testload installed on target 2 tracepoint keep y 0x080483bc in func1 at ../.././../git/gdb/testsuite/gdb.trace/circ.c:32 collect testload installed on target (gdb) c Continuing. Breakpoint 3, end () at ../.././../git/gdb/testsuite/gdb.trace/circ.c:72 72 } (gdb) tstop (gdb) tfind start Found trace frame 0, tracepoint 1 #0 func0 () at ../.././../git/gdb/testsuite/gdb.trace/circ.c:28 28 } (gdb) tfind Found trace frame 1, tracepoint 2 32 } (gdb) When we don't have info about the stack available (UNWIND_UNAVAILABLE), frames end up with outer_frame_id as frame ID. And in the scenario above, the issue is that both frames before and after the second tfind (the frames for func0 an func1) have the same id (outer_frame_id), so the frame_id_eq check returns false, even though the frames were of different functions. GDB knows that, because the PC is inferred from the tracepoint's address, even if no registers were collected. To fix this, this patch adds support for frame ids with a valid code address, but stack address, and then makes the unwinders use that instead of the catch-all outer_frame_id for such frames. The frame_id_eq check in tfind_1 then automatically does the right thing as expected. I tested with --directory=gdb.trace/ , before/after the patch, and compared the resulting gdb.logs, then adjusted the tests to expect the extra output that came out. Turns out that was only circ.exp, the original test that actually brought this issue to light. Tested on x86_64 Fedora 17, native and gdbserver. gdb/ 2013-12-17 Pedro Alves * frame.h (enum frame_id_stack_status): New enum. (struct frame_id) : Adjust comment. : Delete field, replaced with ... : ... this new field. (frame_id_build_unavailable_stack): Declare. * frame.c (frame_addr_hash, fprint_field, outer_frame_id) (frame_id_build_special): Adjust. (frame_id_build_unavailable_stack): New function. (frame_id_build, frame_id_build_wild): Adjust. (frame_id_p, frame_id_eq, frame_id_inner): Adjust to take into account frames with unavailable stack. * amd64-tdep.c (amd64_frame_this_id) (amd64_sigtramp_frame_this_id, amd64_epilogue_frame_this_id): Use frame_id_build_unavailable_stack. * dwarf2-frame.c (dwarf2_frame_this_id): Likewise. * i386-tdep.c (i386_frame_this_id, i386_epilogue_frame_this_id) (i386_sigtramp_frame_this_id): Likewise. gdb/testsuite/ 2013-12-17 Pedro Alves * gdb.trace/circ.exp: Expect frame info to be printed when switching between frames with unavailable stack, but different functions. --- gdb/i386-tdep.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) (limited to 'gdb/i386-tdep.c') diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c index a1a4453..5b4a5a3 100644 --- a/gdb/i386-tdep.c +++ b/gdb/i386-tdep.c @@ -1905,12 +1905,17 @@ i386_frame_this_id (struct frame_info *this_frame, void **this_cache, { struct i386_frame_cache *cache = i386_frame_cache (this_frame, this_cache); - /* This marks the outermost frame. */ - if (cache->base == 0) - return; - - /* See the end of i386_push_dummy_call. */ - (*this_id) = frame_id_build (cache->base + 8, cache->pc); + if (!cache->base_p) + (*this_id) = frame_id_build_unavailable_stack (cache->pc); + else if (cache->base == 0) + { + /* This marks the outermost frame. */ + } + else + { + /* See the end of i386_push_dummy_call. */ + (*this_id) = frame_id_build (cache->base + 8, cache->pc); + } } static enum unwind_stop_reason @@ -2091,9 +2096,9 @@ i386_epilogue_frame_this_id (struct frame_info *this_frame, i386_epilogue_frame_cache (this_frame, this_cache); if (!cache->base_p) - return; - - (*this_id) = frame_id_build (cache->base + 8, cache->pc); + (*this_id) = frame_id_build_unavailable_stack (cache->pc); + else + (*this_id) = frame_id_build (cache->base + 8, cache->pc); } static struct value * @@ -2284,10 +2289,12 @@ i386_sigtramp_frame_this_id (struct frame_info *this_frame, void **this_cache, i386_sigtramp_frame_cache (this_frame, this_cache); if (!cache->base_p) - return; - - /* See the end of i386_push_dummy_call. */ - (*this_id) = frame_id_build (cache->base + 8, get_frame_pc (this_frame)); + (*this_id) = frame_id_build_unavailable_stack (get_frame_pc (this_frame)); + else + { + /* See the end of i386_push_dummy_call. */ + (*this_id) = frame_id_build (cache->base + 8, get_frame_pc (this_frame)); + } } static struct value * -- cgit v1.1