lldb/examples/python/armv7_cortex_m_target_defintion.py

#!/usr/bin/env python
#===-- armv7_cortex_m_target_definition.py.py ------------------*- C++ -*-===//
#
#                     The LLVM Compiler Infrastructure
#
# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#
#===----------------------------------------------------------------------===//

#----------------------------------------------------------------------
# DESCRIPTION
#
# This file can be used with the following setting:
#   plugin.process.gdb-remote.target-definition-file
# This setting should be used when you are trying to connect to a 
# remote GDB server that doesn't support any of the register discovery
# packets that LLDB normally uses. 
#
# Why is this necessary? LLDB doesn't require a new build of LLDB that
# targets each new architecture you will debug with. Instead, all
# architectures are supported and LLDB relies on extra GDB server 
# packets to discover the target we are connecting to so that is can
# show the right registers for each target. This allows the GDB server
# to change and add new registers without requiring a new LLDB build
# just so we can see new registers.
#
# This file implements the x86_64 registers for the darwin version of
# GDB and allows you to connect to servers that use this register set. 
# 
# USAGE
#
# (lldb) settings set plugin.process.gdb-remote.target-definition-file /path/to/armv7_cortex_m_target_defintion.py
# (lldb) gdb-remote other.baz.com:1234
#
# The target definition file will get used if and only if the 
# qRegisterInfo packets are not supported when connecting to a remote
# GDB server.
#----------------------------------------------------------------------

from lldb import *

# DWARF register numbers
name_to_dwarf_regnum = {
    'r0'   : 0 ,     
    'r1'   : 1 ,
    'r2'   : 2 ,
    'r3'   : 3 ,
    'r4'   : 4 ,
    'r5'   : 5 ,
    'r6'   : 6 ,
    'r7'   : 7 ,
    'r9'   : 8 ,
    'r10'  : 9 ,
    'r11'  : 10,
    'r12'  : 11,
    'sp'   : 12,
    'lr'   : 13,
    'pc'   : 14,
    'r15'  : 15,
    'xpsr' : 16,
};

name_to_generic_regnum = {
    'pc' : LLDB_REGNUM_GENERIC_PC,
    'sp' : LLDB_REGNUM_GENERIC_SP,
    'r7' : LLDB_REGNUM_GENERIC_FP,
    'lr' : LLDB_REGNUM_GENERIC_RA,
    'r0' : LLDB_REGNUM_GENERIC_ARG1,
    'r1' : LLDB_REGNUM_GENERIC_ARG2,
    'r2' : LLDB_REGNUM_GENERIC_ARG3,
    'r3' : LLDB_REGNUM_GENERIC_ARG4
};


def get_reg_num (reg_num_dict, reg_name):
    if reg_name in reg_num_dict:
        return reg_num_dict[reg_name]
    return LLDB_INVALID_REGNUM

def get_reg_num (reg_num_dict, reg_name):
    if reg_name in reg_num_dict:
        return reg_num_dict[reg_name]
    return LLDB_INVALID_REGNUM
    
armv7_register_infos = [
{ 'name':'r0'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'arg1' },
{ 'name':'r1'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'arg2' },
{ 'name':'r2'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'arg3' },
{ 'name':'r3'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'arg4' },
{ 'name':'r4'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r5'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r6'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r7'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'fp'  },
{ 'name':'r8'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r9'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r10'  , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r11'  , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'r12'  , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo   },
{ 'name':'sp'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'r13'  },
{ 'name':'lr'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'r14'  },
{ 'name':'pc'   , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'r15'  },
{ 'name':'xpsr' , 'set':0, 'bitsize':32 , 'encoding':eEncodingUint  , 'format':eFormatAddressInfo, 'alt-name':'cpsr' },
];

g_target_definition = None

def get_target_definition ():
    global g_target_definition
    if g_target_definition == None:
        g_target_definition = {}
        offset = 0
        for reg_info in armv7_register_infos:
            reg_name = reg_info['name']

            if 'slice' not in reg_info and 'composite' not in reg_info:
                reg_info['offset'] = offset
                offset += reg_info['bitsize'] / 8

            # Set the DWARF/eh_frame register number for this register if it has one    
            reg_num = get_reg_num(name_to_dwarf_regnum, reg_name)
            if reg_num != LLDB_INVALID_REGNUM:
                reg_info['gcc'] = reg_num
                reg_info['ehframe'] = reg_num

            # Set the generic register number for this register if it has one    
            reg_num = get_reg_num(name_to_generic_regnum, reg_name)
            if reg_num != LLDB_INVALID_REGNUM:
                reg_info['generic'] = reg_num

        g_target_definition['sets'] = ['General Purpose Registers']
        g_target_definition['registers'] = armv7_register_infos
        g_target_definition['host-info'] = { 'triple'   : 'armv7em--', 'endian': eByteOrderLittle }
        g_target_definition['g-packet-size'] = offset
    return g_target_definition

def get_dynamic_setting(target, setting_name):
    if setting_name == 'gdb-server-target-definition':
        return get_target_definition()