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ruby--ruby/misc/lldb_disasm.py
Aaron Patterson 3d474e19fd Rudimentary support for disassembling rb_iseq_t
I need to disassemble instruction sequences while debugging, so I wrote
this.

Usage is like this:

```
(lldb) p iseq
(rb_iseq_t *) $147 = 0x0000000101068400
(lldb) rbdisasm iseq
0000 putspecialobject( 3 )
0002 putnil
0003 defineclass( ID: 0x560b, (rb_iseq_t *)0x1010681d0, 2 )
0007 pop
0008 putspecialobject( 3 )
0010 putnil
0011 defineclass( ID: 0x56eb, (rb_iseq_t *)0x101063b58, 2 )
0015 leave
```

Also thanks a ton to @kivikakk helping me figure out how to navigate LLDB's Python 😆
2020-09-22 13:40:57 -07:00

197 lines
7.4 KiB
Python

#!/usr/bin/env python
#coding: utf-8
#
# Usage: run `command script import -r misc/lldb_disasm.py` on LLDB
#
#
# (lldb) p iseq
# (rb_iseq_t *) $147 = 0x0000000101068400
# (lldb) rbdisasm iseq
# 0000 putspecialobject( 3 )
# 0002 putnil
# 0003 defineclass( ID: 0x560b, (rb_iseq_t *)0x1010681d0, 2 )
# 0007 pop
# 0008 putspecialobject( 3 )
# 0010 putnil
# 0011 defineclass( ID: 0x56eb, (rb_iseq_t *)0x101063b58, 2 )
# 0015 leave
import lldb
import os
import shlex
class IseqDissassembler:
TS_VARIABLE = b'.'[0]
TS_CALLDATA = b'C'[0]
TS_CDHASH = b'H'[0]
TS_IC = b'K'[0]
TS_IVC = b'A'[0]
TS_ID = b'I'[0]
TS_ISE = b'T'[0]
TS_ISEQ = b'S'[0]
TS_OFFSET = b'O'[0]
TS_VALUE = b'V'[0]
TS_LINDEX = b'L'[0]
TS_FUNCPTR = b'F'[0]
TS_NUM = b'N'[0]
TS_BUILTIN = b'R'[0]
ISEQ_OPT_DISPATCH = {
TS_BUILTIN: "(rb_builtin_function *)%0#x",
TS_NUM: "%d",
TS_FUNCPTR: "(rb_insn_func_t) %0#x",
TS_LINDEX: "%d",
TS_VALUE: "(VALUE)%0#x",
TS_OFFSET: "%d",
TS_ISEQ: "(rb_iseq_t *)%0#x",
TS_ISE: "(iseq_inline_storage_entry *)%0#x",
TS_ID: "ID: %0#x",
TS_IVC: "(struct iseq_inline_iv_cache_entry *)%0#x",
TS_IC: "(struct iseq_inline_cache_entry *)%0#x",
TS_CDHASH: "CDHASH (VALUE)%0#x",
TS_CALLDATA: "(struct rb_call_data *)%0#x",
TS_VARIABLE: "VARIABLE %0#x",
}
def __init__(self, debugger, command, result, internal_dict):
self.debugger = debugger
self.command = command
self.result = result
self.internal_dict = internal_dict
self.target = debugger.GetSelectedTarget()
self.process = self.target.GetProcess()
self.thread = self.process.GetSelectedThread()
self.frame = self.thread.GetSelectedFrame()
self.addr2insn = self.build_addr2insn(self.target)
self.tChar = self.target.FindFirstType("char")
def disasm(self, val):
tRbISeq = self.target.FindFirstType("struct rb_iseq_struct").GetPointerType()
val = val.Cast(tRbISeq)
iseq_size = val.GetValueForExpressionPath("->body->iseq_size").GetValueAsUnsigned()
iseqs = val.GetValueForExpressionPath("->body->iseq_encoded")
idx = 0
while idx < iseq_size:
idx += self.iseq_extract_values(self.debugger, self.target, self.process, self.result, iseqs, idx)
def build_addr2insn(self, target):
tIntPtr = target.FindFirstType("intptr_t")
size = target.EvaluateExpression('ruby_vminsn_type::VM_INSTRUCTION_SIZE').unsigned
sizeOfIntPtr = tIntPtr.GetByteSize()
addr_of_table = target.FindSymbols("vm_exec_core.insns_address_table")[0].GetSymbol().GetStartAddress().GetLoadAddress(target)
my_dict = {}
for insn in range(size):
addr_in_table = addr_of_table + (insn * sizeOfIntPtr)
addr = lldb.SBAddress(addr_in_table, target)
machine_insn = target.CreateValueFromAddress("insn", addr, tIntPtr).GetValueAsUnsigned()
my_dict[machine_insn] = insn
return my_dict
def rb_vm_insn_addr2insn2(self, target, result, wanted_addr):
return self.addr2insn.get(wanted_addr)
def iseq_extract_values(self, debugger, target, process, result, iseqs, n):
tValueP = target.FindFirstType("VALUE")
sizeofValueP = tValueP.GetByteSize()
insn = target.CreateValueFromAddress(
"i", lldb.SBAddress(iseqs.unsigned + (n * sizeofValueP), target), tValueP)
addr = insn.GetValueAsUnsigned()
orig_insn = self.rb_vm_insn_addr2insn2(target, result, addr)
name = self.insn_name(target, process, result, orig_insn)
length = self.insn_len(target, orig_insn)
op_types = bytes(self.insn_op_types(target, process, result, orig_insn), 'utf-8')
print("%04d %s" % (n, name), file=result, end="")
if length == 1:
print("", file=result)
return length
print("(", end="", file=result)
for idx, op_type in enumerate(op_types):
if idx == 0:
print(" ", end="", file=result)
else:
print(", ", end="", file=result)
opAddr = lldb.SBAddress(iseqs.unsigned + ((n + idx + 1) * sizeofValueP), target)
opValue = target.CreateValueFromAddress("op", opAddr, tValueP)
op = opValue.GetValueAsUnsigned()
print(self.ISEQ_OPT_DISPATCH.get(op_type) % op, end="", file=result)
print(" )", file=result)
return length
def insn_len(self, target, offset):
size_of_char = self.tChar.GetByteSize()
addr_of_table = target.FindSymbols("insn_len.t")[0].GetSymbol().GetStartAddress().GetLoadAddress(target)
addr_in_table = addr_of_table + (offset * size_of_char)
addr = lldb.SBAddress(addr_in_table, target)
return target.CreateValueFromAddress("y", addr, self.tChar).GetValueAsUnsigned()
def insn_op_types(self, target, process, result, insn):
tUShort = target.FindFirstType("unsigned short")
self.tChar = target.FindFirstType("char")
size_of_short = tUShort.GetByteSize()
size_of_char = self.tChar.GetByteSize()
addr_of_table = target.FindSymbols("insn_op_types.y")[0].GetSymbol().GetStartAddress().GetLoadAddress(target)
addr_in_table = addr_of_table + (insn * size_of_short)
addr = lldb.SBAddress(addr_in_table, target)
offset = target.CreateValueFromAddress("y", addr, tUShort).GetValueAsUnsigned()
addr_of_table = target.FindSymbols("insn_op_types.x")[0].GetSymbol().GetStartAddress().GetLoadAddress(target)
addr_in_name_table = addr_of_table + (offset * size_of_char)
error = lldb.SBError()
return process.ReadCStringFromMemory(addr_in_name_table, 256, error)
def insn_name_table_offset(self, target, offset):
tUShort = target.FindFirstType("unsigned short")
size_of_short = tUShort.GetByteSize()
addr_of_table = target.FindSymbols("insn_name.y")[0].GetSymbol().GetStartAddress().GetLoadAddress(target)
addr_in_table = addr_of_table + (offset * size_of_short)
addr = lldb.SBAddress(addr_in_table, target)
return target.CreateValueFromAddress("y", addr, tUShort).GetValueAsUnsigned()
def insn_name(self, target, process, result, offset):
tCharP = target.FindFirstType("char*")
addr_of_table = target.FindSymbols("insn_name.x")[0].GetSymbol().GetStartAddress().GetLoadAddress(target)
addr_in_name_table = addr_of_table + self.insn_name_table_offset(target, offset)
addr = lldb.SBAddress(addr_in_name_table, target)
error = lldb.SBError()
return process.ReadCStringFromMemory(addr_in_name_table, 256, error)
def disasm(debugger, command, result, internal_dict):
disassembler = IseqDissassembler(debugger, command, result, internal_dict)
frame = disassembler.frame
if frame.IsValid():
val = frame.EvaluateExpression(command)
else:
val = target.EvaluateExpression(command)
error = val.GetError()
if error.Fail():
print >> result, error
return
disassembler.disasm(val);
def __lldb_init_module(debugger, internal_dict):
debugger.HandleCommand("command script add -f lldb_disasm.disasm rbdisasm")
print("lldb Ruby disasm installed.")