Merge pull request #4657 from garazdawi/lukas/erts/lldb-macros

erts: Implement some etp macros for lldb

2 files changed, 672 insertions, 0 deletions

diff --git a/erts/etc/unix/cerl.src b/erts/etc/unix/cerl.src
index f617736e43..adc20f5ac6 100644
--- a/erts/etc/unix/cerl.src
+++ b/erts/etc/unix/cerl.src
@@ -34,6 +34,8 @@
 #               You have to start beam in gdb using "run".
 #   -rgdb       Run the debug compiled emulator in gdb.
 #               You have to start beam in gdb using "run".
+#   -lldb       Run the debug compiled emulator in lldb.
+#               You have to start beam in lldb using "run".
 #   -dump       Dump the bt of all threads in a core.
 #   -break F    Run the debug compiled emulator in emacs and gdb and set break.
 #               The session is started, i.e. "run" is already don for you.
@@ -170,6 +172,10 @@ while [ $# -gt 0 ]; do
 	    shift
 	    GDB=gdb
 	    ;;
+    "-lldb")
+        shift
+        GDB=lldb
+        ;;
 	"-break")
 	    shift
 	    GDB=gdb
@@ -421,6 +427,20 @@ elif [ "x$GDB" = "xgdb" ]; then
     echo "source $ROOTDIR/erts/etc/unix/etp-commands" > $cmdfile
     # Fire up gdb in emacs...
     exec gdb $GDBBP -x $cmdfile $gdbcmd
+elif [ "x$GDB" = "xlldb" ]; then
+    case "x$core" in
+        x)
+            beam_args=`$EXEC -emu_args_exit ${1+"$@"}`
+            lldbcmd="-- $beam_args"
+            ;;
+        *)
+            lldbcmd="--core ${core}"
+            ;;
+    esac
+    cmdfile="/tmp/.cerllldb.$$"
+    echo "env TERM=dumb" > $cmdfile
+    echo "command script import $ROOTDIR/erts/etc/unix/etp.py" >> $cmdfile
+    exec lldb -s $cmdfile $EMU_NAME $lldbcmd
 elif [ "x$GDB" = "xegdb" ]; then
     if [ "x$EMACS" = "x" ]; then
 	EMACS=emacs
diff --git a/erts/etc/unix/etp.py b/erts/etc/unix/etp.py
new file mode 100644
index 0000000000..ca8a15d69d
--- /dev/null
+++ b/erts/etc/unix/etp.py
@@ -0,0 +1,652 @@
+# coding=utf-8
+#
+# %CopyrightBegin%
+# 
+# Copyright Ericsson AB 2013-2022. All Rights Reserved.
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# 
+# %CopyrightEnd%
+#
+#
+# This script was orinally written by Anthony Ramine (aka nox) in 2013
+# A lot of things have changed since then, but the same base remains.
+#
+
+import re
+import lldb
+import shlex
+
+unquoted_atom_re = re.compile(u'^[a-zß-öø-ÿ][a-zA-Zß-öø-ÿ0-9@]*$')
+
+def __lldb_init_module(debugger, internal_dict):
+    debugger.HandleCommand('type format add -f hex Eterm')
+    debugger.HandleCommand('type format add -f hex BeamInstr')
+    debugger.HandleCommand('type summary add -F etp.eterm_summary Eterm')
+    debugger.HandleCommand('command script add -f etp.processes_cmd etp-processes')
+    debugger.HandleCommand('command script add -f etp.process_info_cmd etp-process-info')
+    debugger.HandleCommand('command script add -f etp.stacktrace_cmd etp-stacktrace')
+    debugger.HandleCommand('command script add -f etp.stackdump_cmd etp-stackdump')
+    debugger.HandleCommand('command script add -f etp.eterm_cmd etp')
+
+####################################
+## Print all processes in the system
+####################################
+def processes_cmd(debugger, command, result, internal_dict):
+    target = debugger.GetSelectedTarget()
+    proc = erts_proc(target)
+    proc_r_o = proc.GetChildMemberWithName('r').GetChildMemberWithName('o')
+    proc_max_ix = proc_r_o.GetChildMemberWithName('max')
+    proc_tab = proc_r_o.GetChildMemberWithName('tab').Cast(ProcessPtrPtr(target))
+    proc_cnt = proc.GetChildMemberWithName('vola').GetChildMemberWithName('tile').GetChildMemberWithName('count').GetChildMemberWithName('counter').unsigned
+    invalid_proc = global_var('erts_invalid_process', target).address_of
+    for proc_ix in range(0, proc_max_ix.unsigned):
+        proc = offset(proc_ix, proc_tab).deref
+        if proc.unsigned != 0 and proc.unsigned != invalid_proc.unsigned:
+            print('---')
+            print('  Pix: %d' % proc_ix)
+            process_info(proc)
+            proc_cnt -= 1
+            if proc_cnt == 0:
+                break
+
+############################################
+## Print process-info about a single process
+############################################
+def process_info_cmd(debugger, command, result, internal_dict):
+    target = debugger.GetSelectedTarget()
+    proc = target.process.selected_thread.GetSelectedFrame().EvaluateExpression(command).Cast(ProcessPtr(target))
+    process_info(proc)
+
+def process_info(proc):
+    print('  Pid: %s' % eterm(proc.GetChildMemberWithName('common').GetChildMemberWithName('id')))
+    print('  State: %s' % process_state(proc))
+    print('  Flags: %s' % process_flags(proc))
+    current = proc.GetChildMemberWithName('current')
+    if current.unsigned != 0 and proc.GetChildMemberWithName('state').GetChildMemberWithName('counter').unsigned & 0x800 == 0:
+        print('  Current function: %s' % mfa(current))
+    else:
+        print('  Current function: %s' % 'unknown')
+    i = proc.GetChildMemberWithName('i')
+    if i.unsigned != 0:
+        print('  I: %s' % eterm(i))
+    else:
+        print('  I: %s' % 'unknown')
+    print('  Pointer: %#x' % proc.unsigned)
+
+def process_state(proc):
+    state = proc.GetChildMemberWithName('state').unsigned
+    res = ''
+    if state & 0x80000000:
+        res += "GARBAGE<0x80000000> | "
+    if state & 0x40000000:
+        res += "dirty-running-sys | "
+    if state & 0x20000000:
+        res += "dirty-running | "
+    if state & 0x10000000:
+        res += "dirty-active-sys | "
+    if state & 0x8000000:
+        res += "dirty-io-proc | "
+    if state & 0x4000000:
+        res += "dirty-cpu-proc | "
+    if state & 0x2000000:
+        res += "sig-q | "
+    if state & 0x1000000:
+        res += "off-heap-msgq | "
+    if state & 0x800000:
+        res += "delayed-sys | "
+    if state & 0x400000:
+        res += "proxy | "
+        proxy_process = True
+    else:
+        proxy_process = False
+    if state & 0x200000:
+        res += "running-sys | "
+    if state & 0x100000:
+        res += "active-sys | "
+    if state & 0x80000:
+        res += "sig-in-q | "
+    if state & 0x40000:
+        res += "sys-tasks | "
+    if state & 0x20000:
+        res += "garbage-collecting | "
+    if state & 0x10000:
+        res += "suspended | "
+    if state & 0x8000:
+        res += "running | "
+    if state & 0x4000:
+        res += "in-run-queue | "
+    if state & 0x2000:
+        res += "active | "
+    if state & 0x1000:
+        res += "unused | "
+    if state & 0x800:
+        res += "exiting | "
+    if state & 0x400:
+        res += "free | "
+    if state & 0x200:
+        res += "in-prq-low | "
+    if state & 0x100:
+        res += "in-prq-normal | "
+    if state & 0x80:
+        res += "in-prq-high | "
+    if state & 0x40:
+        res += "in-prq-max | "
+    if state & 0x30 == 0x0:
+        res += "prq-prio-max | "
+    elif state & 0x30 == 0x10:
+      res += "prq-prio-high | "
+    elif state & 0x30 == 0x20:
+        res += "prq-prio-normal | "
+    else:
+        res += "prq-prio-low | "
+    if state & 0xc == 0x0:
+        res += "usr-prio-max | "
+    elif state & 0xc == 0x4:
+      res += "usr-prio-high | "
+    elif state & 0xc == 0x8:
+        res += "usr-prio-normal | "
+    else:
+        res += "usr-prio-low | "
+    if state & 0x3 == 0x0:
+        res += "act-prio-max"
+    elif state & 0x3 == 0x1:
+      res += "act-prio-high"
+    elif state & 0x3 == 0x2:
+        res += "act-prio-normal"
+    else:
+        res += "act-prio-low"
+    return res
+
+def process_flags(proc):
+    flags = proc.GetChildMemberWithName('flags').unsigned
+    res = ''
+    if flags & ~((1 << 24)-1):
+        res += "GARBAGE<%#x> " % (flags & ~((1 << 24)-1))
+    if flags & (1 << 22):
+        res += "trap-exit "
+    if flags & (1 << 21):
+        res += "hibernated "
+    if flags & (1 << 20):
+        res += "dirty-minor-gc "
+    if flags & (1 << 19):
+        res += "dirty-major-gc "
+    if flags & (1 << 18):
+        res += "dirty-gc-hibernate "
+    if flags & (1 << 17):
+        res += "dirty-cla "
+    if flags & (1 << 16):
+        res += "delayed-del-proc "
+    if flags & (1 << 15):
+        res += "have-blocked-nmsb "
+    if flags & (1 << 14):
+        res += "shdlr-onln-wait-q "
+    if flags & (1 << 13):
+        res += "delay-gc "
+    if flags & (1 << 12):
+        res += "abandoned-heap-use "
+    if flags & (1 << 11):
+        res += "disable-gc "
+    if flags & (1 << 10):
+        res += "force-gc "
+    if flags & (1 << 9):
+        res += "ets-super-user "
+    if flags & (1 << 8):
+        res += "have-blocked-msb "
+    if flags & (1 << 7):
+        res += "using-ddll "
+    if flags & (1 << 6):
+        res += "distribution "
+    if flags & (1 << 5):
+        res += "using-db "
+    if flags & (1 << 4):
+        res += "need-fullsweep "
+    if flags & (1 << 3):
+        res += "heap-grow "
+    if flags & (1 << 2):
+        res += "timo "
+    if flags & (1 << 1):
+        res += "inslpqueue "
+    if flags & (1 << 0):
+        res += "hibernate-sched "
+    return res
+
+############################################
+## Print the stacktrace of a single process
+############################################
+def stacktrace_cmd(debugger, command, result, internal_dict):
+    target = debugger.GetSelectedTarget()
+    proc = target.process.selected_thread.GetSelectedFrame().EvaluateExpression(command).Cast(ProcessPtr(target))
+    stackdump(proc, False)
+
+############################################
+## Print the stackdump of a single process
+############################################
+def stackdump_cmd(debugger, command, result, internal_dict):
+    target = debugger.GetSelectedTarget()
+    proc = target.process.selected_thread.GetSelectedFrame().EvaluateExpression(command).Cast(ProcessPtr(target))
+    stackdump(proc, True)
+
+def stackdump(proc, dump):
+    stop = proc.GetChildMemberWithName('stop')
+    send = proc.GetChildMemberWithName('hend')
+    cnt = 0
+    if proc.GetChildMemberWithName('state').GetChildMemberWithName('counter').unsigned & 0x8000:
+        print('%%%%%% WARNING: The process is currently running, so c_p->stop will not be correct')
+    print(F'%% Stacktrace ({send.unsigned - stop.unsigned})');
+    i = proc.GetChildMemberWithName('i')
+    if i.unsigned != 0:
+        print(F'I: {eterm(i)}')
+    while stop.unsigned < send.unsigned:
+        if stop.deref.unsigned & 0x3 == 0x0 or dump:
+            print(F'{cnt}: {eterm(stop.deref)}')
+        cnt += 1
+        stop = offset(1, stop)
+
+############################################
+## Print an eterm
+############################################
+def eterm_cmd(debugger, command, result, internal_dict):
+    args = shlex.split(command)
+    target = debugger.GetSelectedTarget()
+    term = target.process.selected_thread.GetSelectedFrame().EvaluateExpression(args[0]).Cast(EtermPtr(target))
+    if len(args) >= 2:
+        print(eterm(term, int(args[1])))
+    else:
+        print(eterm(term))
+
+############################################
+## Print the summary of an Eterm
+############################################
+def eterm_summary(valobj, internal_dict):
+    if valobj.TypeIsPointerType():
+        return ''
+    return F'{valobj.unsigned:#x} {eterm(valobj, 5)}'
+
+def eterm(valobj, depth = float('inf')):
+    val = valobj.unsigned
+    tag = val & 0x3
+    if tag == 0x1:
+        return cons(valobj, depth)
+    elif tag == 0x2:
+        return boxed(valobj, depth)
+    elif tag == 0x3:
+        return imm(valobj)
+    elif val == 0x0:
+        return '<the non-value>'
+    elif val == 0x4:
+        return '<the non-value debug>'
+    else:
+        return cp(valobj)
+
+def cons(valobj, depth = float('inf')):
+    items = []
+    cdr = valobj
+    improper = False
+    truncated = False
+    depth *= 20
+    
+    while True:
+        ptr = cdr.CreateValueFromData(
+            "unconsed",
+            lldb.SBData.CreateDataFromInt(cdr.unsigned - 1),
+            EtermPtr(cdr.target))
+        items.append((ptr.deref, depth // 20)); # Append depth, car
+        if ptr.deref.unsigned & 0xF == 0xF:
+            depth -= 1
+        else:
+            depth -= 20
+        cdr = offset(1,ptr).deref
+        if is_nil(cdr):
+            break
+        if cdr.unsigned & 0x1 == 0:
+            improper = True
+            break
+        if depth <= 1:
+            truncated = True
+            break
+
+    if improper:
+        return '#ImproperList'
+
+    ## Try to print as ascii first
+    chars = ''
+    isprintable = True
+    for car, car_depth in items:
+        if car.unsigned & 0xF == 0xF:
+            if car.unsigned >> 4 == 10:
+                chars += '\\n'
+            elif car.unsigned >> 4 == 9:
+                chars += '\\t'
+            else:
+                chars += f'{car.unsigned >> 4:c}'
+        else:
+            isprintable = False
+            break
+    isprintable = isprintable and chars.isprintable()
+    if isprintable:
+        if not truncated:
+            return F'"{chars}"'
+        else:
+            return F'"{chars}..."'
+
+    ## If not printable, we print the objects
+    objs = []
+    chars = '['
+    for car, car_depth in items:
+        objs.append(eterm(car, car_depth))
+    if not truncated:
+        return '[' + ','.join(objs) + ']'
+    else:
+        return '[' + ','.join(objs) + '|...]'
+
+def boxed(valobj, depth = float('inf')):
+    ptr = valobj.CreateValueFromData(
+        "unboxed",
+        lldb.SBData.CreateDataFromInt(valobj.unsigned - 2),
+        EtermPtr(valobj.target))
+    boxed_hdr = ptr.deref.unsigned
+    if boxed_hdr & 0x3f == 0x00:
+        arity = (boxed_hdr >> 6)
+        terms = []
+        for x in range(1, arity+1):
+            if depth <= 1:
+                terms.append('...')
+                break
+            depth -= 1
+            terms.append(eterm(offset(x, ptr).deref, depth))
+        res = ','.join(terms)
+        return F"{{{res}}}"
+    if boxed_hdr & 0x3c == 0x3c:
+        if boxed_hdr & 0xc0 == 0x0:
+            return "flat_map"
+        else:
+            return "hash_map"
+    boxed_type = (boxed_hdr >> 2) & 0xF
+    if boxed_type == 0xC:
+        return '#ExternalPid'
+    if boxed_type == 0xD:
+        return '#ExternalPort'
+    if boxed_type == 0x2 or boxed_type == 0x3:
+        return '#Bignum'
+    if boxed_type == 0x6:
+        return '#Float'
+    if boxed_type == 0x4:
+        return '#Ref'
+    if boxed_type == 0xE:
+        return '#ExternalRef'
+    if boxed_type == 0x5:
+        return '#Fun'
+    if boxed_type == 0x8:
+        return '#RefcBin'
+    if boxed_type == 0x9:
+        return '#HeapBin'
+    if boxed_type == 0xA:
+        return '#SubBin'
+    return F'#Boxed<{valobj.unsigned}>'
+
+def imm(valobj):
+    val = valobj.unsigned
+    if (val & 0x3) != 3:
+        return '#NotImmediate<%#x>' % val
+    tag = val & 0xF
+    if tag == 0x3:
+        return pid(valobj)
+    elif tag == 0x7:
+        return port(valobj)
+    elif tag == 0xF:
+        return str(val >> 4)
+    elif tag == 0xB:
+        # Immediate2
+        tag2 = val & 0x3F
+        if tag2 == 0x0B:
+            return atom(valobj)
+        elif tag2 == 0x1B:
+            return F'#Catch<{val>>6:#x}>'
+        elif is_nil(valobj):
+            return '[]'
+    return '#UnknownImmediate<%#x>' % val
+
+# Continuation pointers
+
+def cp(valobj):
+    mfaptr = erts_lookup_function_info(valobj)
+    if mfaptr == None:
+        return '#Cp<%#x>' % valobj.unsigned
+    else:
+        return '#Cp<%s>' % mfa(mfaptr)
+
+# Pids and ports
+
+def pid(valobj):
+    val = valobj.unsigned
+    if (val & 0xF) == 0x3:
+        target = valobj.target
+        if etp_arch_bits(target) == 64:
+            if etp_big_endian(target):
+                data = (val >> 35) & 0x0FFFFFFF
+            else:
+                data = (val >> 4) & 0x0FFFFFFF
+        else:
+            data = pixdata2data(valobj)
+        return '<0.%u.%u>' % (data & 0x7FFF, (data >> 15) & 0x1FFF)
+    else:
+        return '#NotPid<%#x>' % val
+
+def port(valobj):
+    val = valobj.unsigned
+    if (val & 0xF) == 0x7:
+        target = valobj.target
+        if etp_arch_bits(target) == 64 and not etp_halfword(target):
+            if etp_big_endian(target):
+                data = (val >> 36) & 0x0FFFFFFF
+            else:
+                data = (val >> 4) & 0x0FFFFFFF
+        else:
+            data = pixdata2data(valobj)
+        return '#Port<0.%u>' % data
+    else:
+        return '#NotPort<%#x>' % val
+
+# Strings and atoms
+
+def atom(valobj):
+    val = valobj.unsigned
+    if (val & 0x3F) == 0x0B:
+        name = atom_name(atom_tab(valobj))
+        if unquoted_atom_re.match(name):
+            return str(name)
+        else:
+            return quoted_name(name, "'")
+    else:
+        return '#NotAtom<%#x>' % val
+
+def atom_name(entry):
+    name = entry.GetChildMemberWithName('name')
+    length = entry.GetChildMemberWithName('len').unsigned
+    data = name.GetPointeeData(0, length).uint8s
+    return ''.join(map(chr, data))
+
+def quoted_name(name, quote):
+    return quote + ''.join(map(lambda c: quoted_char(c, quote), name)) + quote
+
+def quoted_char(c, quote):
+    point = ord(c)
+    if c == quote:
+        return '\\' + quote
+    elif point == 0x08:
+        return '\\b'
+    elif point == 0x09:
+        return '\\t'
+    elif point == 0x0A:
+        return '\\n'
+    elif point == 0x0B:
+        return '\\v'
+    elif point == 0x0C:
+        return '\\f'
+    elif point == 0x0D:
+        return '\\e'
+    elif point >= 0x20 and point <= 0x7E or point >= 0xA0:
+        return c
+    elif (point > 0xFF):
+        return '#NotChar<%#x>' % c
+    else:
+        return '\\%03o' % point
+
+# Constants
+
+MI_FUNCTIONS = 13
+MI_NUM_FUNCTIONS = 0
+
+def is_nil(value):
+    ## We handle both -5 and 0x3b as NIL values so that this script
+    ## works with more versions
+    return value.signed == -5 or value.unsigned == 0x3b
+
+# Types
+
+def Atom(target):
+    return target.FindFirstType('Atom')
+
+def Char(target):
+    return target.FindFirstType('char')
+def CharPtr(target):
+    return Char(target).GetPointerType()
+
+def Eterm(target):
+    return target.FindFirstType('Eterm')
+def EtermPtr(target):
+    return Eterm(target).GetPointerType()
+def EtermPtrPtr(target):
+    return EtermPtr(target).GetPointerType()
+
+def Range(target):
+    return target.FindFirstType('Range')
+
+def BeamInstr(target):
+    return target.FindFirstType('BeamInstr')
+def BeamInstrPtr(target):
+    return BeamInstr(target).GetPointerType()
+
+def ErtsCodeInfo(target):
+    return target.FindFirstType('ErtsCodeInfo')
+def ErtsCodeInfoPtr(target):
+    return ErtsCodeInfo(target).GetPointerType()
+
+def Process(target):
+    return target.FindFirstType('Process')
+def ProcessPtr(target):
+    return Process(target).GetPointerType()
+def ProcessPtrPtr(target):
+    return ProcessPtr(target).GetPointerType()
+
+# Globals
+
+def erts_atom_table(target):
+    return global_var('erts_atom_table', target)
+
+def erts_proc(target):
+    return global_var('erts_proc', target)
+
+def etp_arch_bits(target):
+    return global_var('etp_arch_bits', target).unsigned
+
+def etp_big_endian(target):
+    return global_var('etp_endianness', target).unsigned > 0
+
+def etp_halfword(target):
+    return False
+
+def the_active_code_index(target):
+    return global_var('the_active_code_index', target)
+
+# Functions
+
+def atom_tab(valobj):
+    idx = valobj.unsigned
+    target = valobj.target
+    seg = erts_atom_table(target).GetChildMemberWithName('seg_table')
+    slot = offset(idx >> 16, seg).deref
+    entry = offset(idx >> 6 & 0x3FF, slot).deref
+    return entry.Cast(Atom(target).GetPointerType())
+
+def erts_lookup_function_info(valobj):
+    r = find_range(valobj)
+    if r is None:
+        return None
+    pc = valobj.unsigned
+    target = valobj.target
+    start = r.GetChildMemberWithName('start').Cast(EtermPtr(target))
+    curr = offset(MI_FUNCTIONS, start).Cast(ErtsCodeInfoPtr(target).GetPointerType())
+    prev = curr
+    cnt = offset(MI_NUM_FUNCTIONS, start).deref.unsigned
+    for x in range(0, cnt):
+        prev = curr
+        curr = offset(1, curr)
+        if pc < curr.deref.unsigned:
+            return prev.deref.GetChildMemberWithName('mfa')
+    return None
+
+def find_range(valobj):
+    pc = valobj.unsigned
+    target = valobj.target
+    active = the_active_code_index(target).unsigned
+    ranges = offset(active, global_var('r', target))
+    n = ranges.GetChildMemberWithName('n').unsigned
+    low = ranges.GetChildMemberWithName('modules')
+    high = offset(n, low)
+    range_type = Range(target)
+    range_pointer_type = range_type.GetPointerType()
+    mid = ranges.GetChildMemberWithName('mid').Cast(range_pointer_type)
+    while low.unsigned < high.unsigned:
+        if pc < mid.GetChildMemberWithName('start').unsigned:
+            high = mid
+        elif pc > mid.GetChildMemberWithName('end').GetChildMemberWithName('counter').unsigned:
+            low = offset(1, mid).Cast(range_pointer_type)
+        else:
+            return mid
+        length = (high.unsigned - low.unsigned) // range_type.size
+        mid = offset(length // 2, low)
+    return None
+
+def mfa(mfa):
+    return '%s:%s/%d' % (eterm(mfa.GetChildMemberWithName('module')),
+                         eterm(mfa.GetChildMemberWithName('function')),
+                         mfa.GetChildMemberWithName('arity').unsigned)
+
+def pixdata2data(valobj):
+    pixdata = valobj.unsigned
+    proc = erts_proc(target)
+    ro = proc.GetChildMemberWithName('r').GetChildMemberWithName('o')
+    pix_mask = ro.GetChildMemberWithName('pix_mask').unsigned
+    pix_cl_mask = ro.GetChildMemberWithName('pix_cl_mask').unsigned
+    pix_cl_shift = ro.GetChildMemberWithName('pix_cl_shift').unsigned
+    pix_cli_mask = ro.GetChildMemberWithName('pix_cli_mask').unsigned
+    pix_cli_shift = ro.GetChildMemberWithName('pix_cli_shift').unsigned
+    data = pixdata & ~pix_mask
+    data |= (pixdata >> pix_cl_shift) & pix_cl_mask
+    data |= (pixdata & pix_cli_mask) << pix_cli_shift
+    return data
+
+# LLDB utils
+
+def global_var(name, target):
+    return target.FindGlobalVariables(name, 1)[0]
+
+def offset(i, valobj):
+    # print("offset(" + str(i) + ", " + str(valobj.unsigned) + ")")
+    val = valobj.GetChildAtIndex(i, lldb.eNoDynamicValues, True)
+    if valobj.TypeIsPointerType():
+        return val.address_of.Cast(valobj.GetType())
+    else:
+        return val