add lldb bthread stack debug script (apache#2514)

* add lldb bthread stack helper script

* fix value as unsigned

tools/lldb_bthread_stack.py

@@ -0,0 +1,347 @@
+#!/usr/bin/env python
+# coding=utf-8
+
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""
+Bthread Stack Print Tool
+
+this only for running process, core dump is not supported.
+
+Get Started:
+    1. lldb attach -p <pid>
+    2. command script import lldb_bthread_stack.py
+    3. bthread_begin
+    4. bthread_list
+    5. bthread_frame 0
+    6. bt / up / down
+    7. bthread_end
+
+Commands:
+    1. bthread_num: print all bthread nums
+    2. bthread_begin <num>: enter bthread debug mode, `num` is max scanned bthreads, default will scan all
+    3. bthread_list: list all bthreads
+    4. bthread_frame <id>: switch stack to bthread, id will displayed in bthread_list
+    5. bthread_meta <id>: print bthread meta
+    6. bthread_reg_restore: bthread_frame will modify registers, reg_restore will restore them
+    7. bthread_end: exit bthread debug mode
+    8. bthread_regs <id>: print bthread registers
+    9. bthread_all: print all bthread frames
+
+when call bthread_frame, registers will be modified,
+remember to call bthread_end after debug, or process will be corrupted
+
+after call bthread_frame, you can call `bt`/`up`/`down`, or other gdb command
+"""
+
+import lldb
+
+
+class GlobalState():
+    def __init__(self):
+        self.started: bool = False
+        self.bthreads: list = []
+        self.saved_regs: dict = {}
+
+    def reset(self) -> None:
+        self.started = False
+        self.bthreads.clear()
+
+    def get_bthread(self, idx_str: str) -> lldb.SBValue:
+        if not self.started:
+            print("Not in bthread debug mode")
+            return None
+        if len(idx_str) == 0:
+            print("bthread_frame <id>, see 'bthread_list'")
+        try:
+            bthread_idx = int(idx_str)
+        except ValueError:
+            print("please input a valid interger.")
+            return None
+
+        if bthread_idx >= len(self.bthreads):
+            print("id {} exceeds max bthread nums {}".format(
+                bthread_idx, len(self.bthreads)))
+            return None
+        return self.bthreads[bthread_idx]
+
+
+global_state = GlobalState()
+
+
+def get_child(value: lldb.SBValue, childs_value_name: str) -> lldb.SBValue:
+    r"""get child value by value name str split by '.'"""
+    result = value
+    childs_value_list = childs_value_name.split('.')
+    for child_value_name in childs_value_list:
+        result = result.GetChildMemberWithName(child_value_name)
+    return result
+
+
+def find_global_value(target: lldb.SBTarget, value_name: str) -> lldb.SBValue:
+    r""" find global value by value name"""
+    name_list = value_name.split('.')
+    root_name = name_list[0]
+    root_value = target.FindGlobalVariables(
+        root_name, 1, lldb.eMatchTypeNormal)[0]
+    if (len(name_list) == 1):
+        return root_value
+    return get_child(root_value, '.'.join(name_list[1:]))
+
+
+def get_bthreads_num(target: lldb.SBTarget):
+    root_agent = find_global_value(
+        target, "bthread::g_task_control._nbthreads._combiner._agents.root_")
+    global_res = find_global_value(
+        target, "bthread::g_task_control._nbthreads._combiner._global_result").GetValueAsSigned()
+    long_type = target.GetBasicType(lldb.eBasicTypeLong)
+
+    last_node = root_agent
+    # agent_type: bvar::detail::AgentCombiner<long, long, bvar::detail::AddTo<long> >::Agent>
+    agent_type: lldb.SBType = last_node.GetType().GetTemplateArgumentType(0)
+    while True:
+        agent = last_node.Cast(agent_type)
+        if (last_node.GetLocation() != root_agent.GetLocation()):
+            val = get_child(agent, "element._value").Cast(
+                long_type).GetValueAsSigned()
+            global_res += val
+        if (get_child(agent, "next_").Dereference().GetLocation() == root_agent.GetLocation()):
+            return global_res
+        last_node = get_child(agent, "next_").Dereference()
+
+
+def get_all_bthreads(target: lldb.SBTarget, total: int):
+    bthreads = []
+    groups = find_global_value(
+        target, "butil::ResourcePool<bthread::TaskMeta>::_ngroup.val").GetValueAsUnsigned()
+    long_type = target.GetBasicType(lldb.eBasicTypeLong)
+    uint32_t_type = target.FindFirstType("uint32_t")
+    block_groups = find_global_value(
+        target, "butil::ResourcePool<bthread::TaskMeta>::_block_groups")
+    for group in range(groups):
+        block_group = get_child(
+            block_groups.GetChildAtIndex(group), "val").Dereference()
+        nblock = get_child(block_group, "nblock").Cast(
+            long_type).GetValueAsUnsigned()
+        blocks = get_child(block_group, "blocks")
+        for block in range(nblock):
+            # block_type: butil::ResourcePool<bthread::TaskMeta>::Block
+            block_type = blocks.GetChildAtIndex(
+                block).GetType().GetTemplateArgumentType(0)
+            block = blocks.GetChildAtIndex(
+                block).Cast(block_type).Dereference()
+            nitem = get_child(block, "nitem").GetValueAsUnsigned()
+            task_meta_array_type = target.FindFirstType(
+                "bthread::TaskMeta").GetArrayType(nitem)
+            tasks = get_child(block, "items").Cast(task_meta_array_type)
+            for i in range(nitem):
+                task_meta = tasks.GetChildAtIndex(i)
+                version_tid = get_child(
+                    task_meta, "tid").GetValueAsUnsigned() >> 32
+                version_butex = get_child(task_meta, "version_butex").Cast(
+                    uint32_t_type.GetPointerType()).Dereference().GetValueAsUnsigned()
+                # stack_type: bthread::ContextualStack
+                stack_type = get_child(
+                    task_meta, "attr.stack_type").GetValueAsUnsigned()
+                if version_tid == version_butex and stack_type != 0:
+                    if len(bthreads) >= total:
+                        return bthreads
+                    bthreads.append(task_meta)
+    return bthreads
+
+# lldb bthread commands
+def bthread_begin(debugger, command, result, internal_dict):
+    if global_state.started:
+        print("Already in bthread debug mode, do not switch thread before exec 'bthread_end' !!!")
+        return
+    target = debugger.GetSelectedTarget()
+    active_bthreads = get_bthreads_num(target)
+
+    if len(command) == 0:
+        request_bthreds = active_bthreads
+    else:
+        try:
+            request_bthreds = int(command)
+        except ValueError:
+            print("please input a valid interger.")
+            return
+
+    scanned_bthreds = active_bthreads
+    if request_bthreds > active_bthreads:
+        print("requested bthreads {} more than actived, will display {} bthreads".format(
+            request_bthreds, active_bthreads))
+    else:
+        scanned_bthreds = request_bthreds
+    print("Active bthreads: {}, will display {} bthreads".format(
+        active_bthreads, scanned_bthreds))
+    global_state.bthreads = get_all_bthreads(target, scanned_bthreds)
+
+    # backup registers
+    current_frame = target.GetProcess().GetSelectedThread().GetSelectedFrame()
+    saved_regs = dict()
+    saved_regs["rip"] = current_frame.FindRegister("rip").GetValueAsUnsigned()
+    saved_regs["rsp"] = current_frame.FindRegister("rsp").GetValueAsUnsigned()
+    saved_regs["rbp"] = current_frame.FindRegister("rbp").GetValueAsUnsigned()
+    global_state.saved_regs = saved_regs
+
+    global_state.started = True
+    print("Enter bthread debug mode, do not switch thread before exec 'bthread_end' !!!")
+
+
+def bthread_list(debugger, command, result, internal_dict):
+    r"""list all bthreads, print format is 'id\ttid\tfunction\thas stack'"""
+    if not global_state.started:
+        print("Not in bthread debug mode")
+        return
+
+    print("id\t\ttid\t\tfunction\t\t\t\thas stack\t\t\ttotal:{}".format(
+        len(global_state.bthreads)))
+    for i, t in enumerate(global_state.bthreads):
+        tid = get_child(t, "tid").GetValueAsUnsigned()
+        fn = get_child(t, "fn")
+        has_stack = get_child(t, "stack").GetLocation() == "0x0"
+        print("#{}\t\t{}\t\t{}\t\t{}".format(
+            i, tid, fn, "no" if has_stack else "yes"))
+
+
+def bthread_num(debugger, command, result, internal_dict):
+    r"""list active bthreads num"""
+    if not global_state.started:
+        print("Not in bthread debug mode")
+        return
+
+    target = debugger.GetSelectedTarget()
+    active_bthreads = get_bthreads_num(target)
+    print(active_bthreads)
+
+
+def bthread_frame(debugger, command, result, internal_dict):
+    r"""bthread_frame <id>, select bthread frame by id"""
+    bthread = global_state.get_bthread(command)
+    if bthread is None:
+        return
+
+    stack = bthread.GetChildMemberWithName("stack")
+    context = stack.Dereference().GetChildMemberWithName("context")
+
+    target = debugger.GetSelectedTarget()
+    uint64_t_type = target.FindFirstType("uint64_t")
+    target = debugger.GetSelectedTarget()
+
+    rip = target.CreateValueFromAddress("rip",  lldb.SBAddress(
+        context.GetValueAsUnsigned() + 7*8, target), uint64_t_type).GetValueAsUnsigned()
+    rbp = target.CreateValueFromAddress("rbp",  lldb.SBAddress(
+        context.GetValueAsUnsigned() + 6*8, target), uint64_t_type).GetValueAsUnsigned()
+    rsp = context.GetValueAsUnsigned() + 8*8
+
+    debugger.HandleCommand(f"register write rip {rip}")
+    debugger.HandleCommand(f"register write rbp {rbp}")
+    debugger.HandleCommand(f"register write rsp {rsp}")
+
+
+def bthread_all(debugger, command, result, internal_dict):
+    r"""print all bthread frames"""
+    if not global_state.started:
+        print("Not in bthread debug mode")
+        return
+
+    bthreads = global_state.bthreads
+    bthread_num = len(bthreads)
+    for i in range(bthread_num):
+        bthread_frame(debugger, str(i), result, internal_dict)
+        debugger.HandleCommand("bt")
+
+
+def bthread_meta(debugger, command, result, internal_dict):
+    r"""bthread_meta <id>, print task meta by id"""
+    bthread = global_state.get_bthread(command)
+    if bthread is None:
+        return
+    print(bthread)
+
+
+def bthread_regs(debugger, command, result, internal_dict):
+    r"""bthread_regs <id>, print bthread registers"""
+    bthread = global_state.get_bthread(command)
+    if bthread is None:
+        return
+    target = debugger.GetSelectedTarget()
+    stack = get_child(bthread, "stack").Dereference()
+    context = get_child(stack, "context")
+    ctx_addr = context.GetValueAsUnsigned()
+    uint64_t_type = target.FindFirstType("uint64_t")
+
+    rip = target.CreateValueFromAddress("rip",  lldb.SBAddress(
+        ctx_addr + 7*8, target), uint64_t_type).GetValueAsUnsigned()
+    rbp = target.CreateValueFromAddress("rbp",  lldb.SBAddress(
+        ctx_addr + 6*8, target), uint64_t_type).GetValueAsUnsigned()
+    rbx = target.CreateValueFromAddress("rbx",  lldb.SBAddress(
+        ctx_addr + 5*8, target), uint64_t_type).GetValueAsUnsigned()
+    r15 = target.CreateValueFromAddress("r15",  lldb.SBAddress(
+        ctx_addr + 4*8, target), uint64_t_type).GetValueAsUnsigned()
+    r14 = target.CreateValueFromAddress("r14",  lldb.SBAddress(
+        ctx_addr + 3*8, target), uint64_t_type).GetValueAsUnsigned()
+    r13 = target.CreateValueFromAddress("r13",  lldb.SBAddress(
+        ctx_addr + 2*8, target), uint64_t_type).GetValueAsUnsigned()
+    r12 = target.CreateValueFromAddress("r12",  lldb.SBAddress(
+        ctx_addr + 1*8, target), uint64_t_type).GetValueAsUnsigned()
+    rsp = ctx_addr + 8*8
+
+    print("rip: 0x{:x}\nrsp: 0x{:x}\nrbp: 0x{:x}\nrbx: 0x{:x}\nr15: 0x{:x}\nr14: 0x{:x}\nr13: 0x{:x}\nr12: 0x{:x}".format(
+        rip, rsp, rbp, rbx, r15, r14, r13, r12))
+
+
+def bthread_reg_restore(debugger, command, result, internal_dict):
+    r"""restore registers"""
+    if not global_state.started:
+        print("Not in bthread debug mode")
+        return
+    for reg_name, reg_value in global_state.saved_regs.items():
+        debugger.HandleCommand(f"register write {reg_name} {reg_value}")
+
+
+def bthread_end(debugger, command, result, internal_dict):
+    r"""exit bthread debug mode"""
+    if not global_state.started:
+        print("Not in bthread debug mode")
+        return
+    bthread_reg_restore(debugger, command, result, internal_dict)
+    global_state.reset()
+    print("Exit bthread debug mode")
+
+
+# And the initialization code to add commands.
+def __lldb_init_module(debugger, internal_dict):
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_begin bthread_begin')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_list bthread_list')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_frame bthread_frame')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_num bthread_num')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_all bthread_all')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_meta bthread_meta')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_regs bthread_regs')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_reg_restore bthread_reg_restore')
+    debugger.HandleCommand(
+        'command script add -f lldb_bthread_stack.bthread_end bthread_end')