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Revert "[tools] Add a simple gdb frame unwinder"

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This reverts commit c3ac338bb9.

Reason for revert: Breaks stepping with `n`

Original change's description:
> [tools] Add a simple gdb frame unwinder
>
> Add a simple unwinder for gdb which, on x64,  walks frame pointers
> whenever there is no source information available. Ideally we would only
> do this for V8 PCs but this appears hard to do in an Unwinder without
> messing with gdb's internal assumptions.
>
> Change-Id: Iba1e62a3768340ee912e81d691237c1920a8ae91
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3608628
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#80204}

Change-Id: I0264cf34cfe8fe2331bacf202dedbb4706535936
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3644855
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80493}
This commit is contained in:
Jakob Kummerow 2022-05-12 14:08:08 +00:00 committed by V8 LUCI CQ
parent 08b3bed2dd
commit a5906c241e
1 changed files with 0 additions and 52 deletions
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52
tools/gdbinit
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@ -259,55 +259,3 @@ gdb.events.new_objfile.connect(newobj_handler)
gdb.execute("set environment V8_GDBINIT_SOURCED=1")
end
# Add a simple unwinder which, on x64, walks frame pointers when there
# is no source information available.
python
from gdb.unwinder import Unwinder
class V8UnwinderFrameId(object):
def __init__(self, sp, pc):
self.sp = sp
self.pc = pc
class V8Unwinder(Unwinder):
def __init__(self):
super(V8Unwinder, self).__init__("V8Unwinder")
self.enabled = True
def __call__(self, pending_frame):
try:
# Only supported on x64.
if gdb.selected_inferior().architecture().name() != "i386:x86-64":
return None
pc = pending_frame.read_register("rip")
sym_and_line = gdb.current_progspace().find_pc_line(int(pc))
if sym_and_line.symtab is not None:
return None
fp = pending_frame.read_register("rbp").reinterpret_cast(
gdb.lookup_type("void").pointer().pointer())
next_sp = fp
next_fp = fp.dereference()
next_pc = (fp+1).dereference()
frame_info = V8UnwinderFrameId(next_sp, next_pc)
# create_unwind_info seems to sometimes have issues accessing
# the frame_info if it's not first accessed in Python.
_lol_gdb_workaround = frame_info.pc + 1
unwind_info = pending_frame.create_unwind_info(frame_info)
unwind_info.add_saved_register("rsp", next_sp)
unwind_info.add_saved_register("rip", next_pc)
unwind_info.add_saved_register("rbp", next_fp)
return unwind_info
except Exception as e:
return None
gdb.unwinder.register_unwinder(None, V8Unwinder(), replace=True)
end