" Debugger plugin using gdb.
"
" Author: Bram Moolenaar
" Copyright: Vim license applies, see ":help license"
" Last Change: 2022 Jan 17
"
" WORK IN PROGRESS - The basics works stable, more to come
" Note: In general you need at least GDB 7.12 because this provides the
" frame= response in MI thread-selected events we need to sync stack to file.
" The one included with "old" MingW is too old (7.6.1), you may upgrade it or
" use a newer version from http://www.equation.com/servlet/equation.cmd?fa=gdb
"
" There are two ways to run gdb:
" - In a terminal window; used if possible, does not work on MS-Windows
"   Not used when g:termdebug_use_prompt is set to 1.
" - Using a "prompt" buffer; may use a terminal window for the program
"
" For both the current window is used to view source code and shows the
" current statement from gdb.
"
" USING A TERMINAL WINDOW
"
" Opens two visible terminal windows:
" 1. runs a pty for the debugged program, as with ":term NONE"
" 2. runs gdb, passing the pty of the debugged program
" A third terminal window is hidden, it is used for communication with gdb.
"
" USING A PROMPT BUFFER
"
" Opens a window with a prompt buffer to communicate with gdb.
" Gdb is run as a job with callbacks for I/O.
" On Unix another terminal window is opened to run the debugged program
" On MS-Windows a separate console is opened to run the debugged program
"
" The communication with gdb uses GDB/MI.  See:
" https://sourceware.org/gdb/current/onlinedocs/gdb/GDB_002fMI.html

" In case this gets sourced twice.
if exists(':Termdebug')
  finish
endif

" Need either the +terminal feature or +channel and the prompt buffer.
" The terminal feature does not work with gdb on win32.
if has('terminal') && !has('win32')
  let s:way = 'terminal'
elseif has('channel') && exists('*prompt_setprompt')
  let s:way = 'prompt'
else
  if has('terminal')
    let s:err = 'Cannot debug, missing prompt buffer support'
  else
    let s:err = 'Cannot debug, +channel feature is not supported'
  endif
  command -nargs=* -complete=file -bang Termdebug echoerr s:err
  command -nargs=+ -complete=file -bang TermdebugCommand echoerr s:err
  finish
endif

let s:keepcpo = &cpo
set cpo&vim

" The command that starts debugging, e.g. ":Termdebug vim".
" To end type "quit" in the gdb window.
command -nargs=* -complete=file -bang Termdebug call s:StartDebug(<bang>0, <f-args>)
command -nargs=+ -complete=file -bang TermdebugCommand call s:StartDebugCommand(<bang>0, <f-args>)

" Name of the gdb command, defaults to "gdb".
if !exists('g:termdebugger')
  let g:termdebugger = 'gdb'
endif

let s:pc_id = 12
let s:asm_id = 13
let s:break_id = 14  " breakpoint number is added to this
let s:stopped = 1

let s:parsing_disasm_msg = 0
let s:asm_lines = []
let s:asm_addr = ''

" Take a breakpoint number as used by GDB and turn it into an integer.
" The breakpoint may contain a dot: 123.4 -> 123004
" The main breakpoint has a zero subid.
func s:Breakpoint2SignNumber(id, subid)
  return s:break_id + a:id * 1000 + a:subid
endfunction

func s:Highlight(init, old, new)
  let default = a:init ? 'default ' : ''
  if a:new ==# 'light' && a:old !=# 'light'
    exe "hi " . default . "debugPC term=reverse ctermbg=lightblue guibg=lightblue"
  elseif a:new ==# 'dark' && a:old !=# 'dark'
    exe "hi " . default . "debugPC term=reverse ctermbg=darkblue guibg=darkblue"
  endif
endfunc

call s:Highlight(1, '', &background)
hi default debugBreakpoint term=reverse ctermbg=red guibg=red
hi default debugBreakpointDisabled term=reverse ctermbg=gray guibg=gray

func s:GetCommand()
  return type(g:termdebugger) == v:t_list ? copy(g:termdebugger) : [g:termdebugger]
endfunc

func s:StartDebug(bang, ...)
  " First argument is the command to debug, second core file or process ID.
  call s:StartDebug_internal({'gdb_args': a:000, 'bang': a:bang})
endfunc

func s:StartDebugCommand(bang, ...)
  " First argument is the command to debug, rest are run arguments.
  call s:StartDebug_internal({'gdb_args': [a:1], 'proc_args': a:000[1:], 'bang': a:bang})
endfunc

func s:StartDebug_internal(dict)
  if exists('s:gdbwin')
    echoerr 'Terminal debugger already running, cannot run two'
    return
  endif
  let gdbcmd = s:GetCommand()
  if !executable(gdbcmd[0])
    echoerr 'Cannot execute debugger program "' .. gdbcmd[0] .. '"'
    return
  endif

  let s:ptywin = 0
  let s:pid = 0
  let s:asmwin = 0

  if exists('#User#TermdebugStartPre')
    doauto <nomodeline> User TermdebugStartPre
  endif

  " Uncomment this line to write logging in "debuglog".
  " call ch_logfile('debuglog', 'w')

  let s:sourcewin = win_getid(winnr())

  " Remember the old value of 'signcolumn' for each buffer that it's set in, so
  " that we can restore the value for all buffers.
  let b:save_signcolumn = &signcolumn
  let s:signcolumn_buflist = [bufnr()]

  let s:save_columns = 0
  let s:allleft = 0
  if exists('g:termdebug_wide')
    if &columns < g:termdebug_wide
      let s:save_columns = &columns
      let &columns = g:termdebug_wide
      " If we make the Vim window wider, use the whole left half for the debug
      " windows.
      let s:allleft = 1
    endif
    let s:vertical = 1
  else
    let s:vertical = 0
  endif

  " Override using a terminal window by setting g:termdebug_use_prompt to 1.
  let use_prompt = exists('g:termdebug_use_prompt') && g:termdebug_use_prompt
  if has('terminal') && !has('win32') && !use_prompt
    let s:way = 'terminal'
  else
    let s:way = 'prompt'
  endif

  if s:way == 'prompt'
    call s:StartDebug_prompt(a:dict)
  else
    call s:StartDebug_term(a:dict)
  endif

  if exists('g:termdebug_disasm_window')
    if g:termdebug_disasm_window
      let curwinid = win_getid(winnr())
      call s:GotoAsmwinOrCreateIt()
      call win_gotoid(curwinid)
    endif
  endif

  if exists('#User#TermdebugStartPost')
    doauto <nomodeline> User TermdebugStartPost
  endif
endfunc

" Use when debugger didn't start or ended.
func s:CloseBuffers()
  exe 'bwipe! ' . s:ptybuf
  exe 'bwipe! ' . s:commbuf
  unlet! s:gdbwin
endfunc

func s:CheckGdbRunning()
  let gdbproc = term_getjob(s:gdbbuf)
  if gdbproc == v:null || job_status(gdbproc) !=# 'run'
    echoerr string(s:GetCommand()[0]) . ' exited unexpectedly'
    call s:CloseBuffers()
    return ''
  endif
  return 'ok'
endfunc

func s:StartDebug_term(dict)
  " Open a terminal window without a job, to run the debugged program in.
  let s:ptybuf = term_start('NONE', {
	\ 'term_name': 'debugged program',
	\ 'vertical': s:vertical,
	\ })
  if s:ptybuf == 0
    echoerr 'Failed to open the program terminal window'
    return
  endif
  let pty = job_info(term_getjob(s:ptybuf))['tty_out']
  let s:ptywin = win_getid(winnr())
  if s:vertical
    " Assuming the source code window will get a signcolumn, use two more
    " columns for that, thus one less for the terminal window.
    exe (&columns / 2 - 1) . "wincmd |"
    if s:allleft
      " use the whole left column
      wincmd H
    endif
  endif

  " Create a hidden terminal window to communicate with gdb
  let s:commbuf = term_start('NONE', {
	\ 'term_name': 'gdb communication',
	\ 'out_cb': function('s:CommOutput'),
	\ 'hidden': 1,
	\ })
  if s:commbuf == 0
    echoerr 'Failed to open the communication terminal window'
    exe 'bwipe! ' . s:ptybuf
    return
  endif
  let commpty = job_info(term_getjob(s:commbuf))['tty_out']

  let gdb_args = get(a:dict, 'gdb_args', [])
  let proc_args = get(a:dict, 'proc_args', [])

  let gdb_cmd = s:GetCommand()
  " Add -quiet to avoid the intro message causing a hit-enter prompt.
  let gdb_cmd += ['-quiet']
  " Disable pagination, it causes everything to stop at the gdb
  let gdb_cmd += ['-iex', 'set pagination off']
  " Interpret commands while the target is running.  This should usually only
  " be exec-interrupt, since many commands don't work properly while the
  " target is running (so execute during startup).
  let gdb_cmd += ['-iex', 'set mi-async on']
  " Open a terminal window to run the debugger.
  let gdb_cmd += ['-tty', pty]
  " Command executed _after_ startup is done, provides us with the necessary feedback
  let gdb_cmd += ['-ex', 'echo startupdone\n']

  " Adding arguments requested by the user
  let gdb_cmd += gdb_args

  call ch_log('executing "' . join(gdb_cmd) . '"')
  let s:gdbbuf = term_start(gdb_cmd, {
	\ 'term_finish': 'close',
	\ })
  if s:gdbbuf == 0
    echoerr 'Failed to open the gdb terminal window'
    call s:CloseBuffers()
    return
  endif
  let s:gdbwin = win_getid(winnr())

  " Wait for the "startupdone" message before sending any commands.
  let try_count = 0
  while 1
    if s:CheckGdbRunning() != 'ok'
      return
    endif

    for lnum in range(1, 200)
      if term_getline(s:gdbbuf, lnum) =~ 'startupdone'
        let try_count = 9999
        break
      endif
    endfor
    let try_count += 1
    if try_count > 300
      " done or give up after five seconds
      break
    endif
    sleep 10m
  endwhile

  " Set arguments to be run.
  if len(proc_args)
    call term_sendkeys(s:gdbbuf, 'server set args ' . join(proc_args) . "\r")
  endif

  " Connect gdb to the communication pty, using the GDB/MI interface.
  " Prefix "server" to avoid adding this to the history.
  call term_sendkeys(s:gdbbuf, 'server new-ui mi ' . commpty . "\r")

  " Wait for the response to show up, users may not notice the error and wonder
  " why the debugger doesn't work.
  let try_count = 0
  while 1
    if s:CheckGdbRunning() != 'ok'
      return
    endif

    let response = ''
    for lnum in range(1, 200)
      let line1 = term_getline(s:gdbbuf, lnum)
      let line2 = term_getline(s:gdbbuf, lnum + 1)
      if line1 =~ 'new-ui mi '
        " response can be in the same line or the next line
        let response = line1 . line2
        if response =~ 'Undefined command'
          echoerr 'Sorry, your gdb is too old, gdb 7.12 is required'
          " CHECKME: possibly send a "server show version" here
          call s:CloseBuffers()
          return
        endif
        if response =~ 'New UI allocated'
          " Success!
          break
        endif
      elseif line1 =~ 'Reading symbols from' && line2 !~ 'new-ui mi '
        " Reading symbols might take a while, try more times
        let try_count -= 1
      endif
    endfor
    if response =~ 'New UI allocated'
      break
    endif
    let try_count += 1
    if try_count > 100
      echoerr 'Cannot check if your gdb works, continuing anyway'
      break
    endif
    sleep 10m
  endwhile

  call job_setoptions(term_getjob(s:gdbbuf), {'exit_cb': function('s:EndTermDebug')})

  " Set the filetype, this can be used to add mappings.
  set filetype=termdebug

  call s:StartDebugCommon(a:dict)
endfunc

func s:StartDebug_prompt(dict)
  " Open a window with a prompt buffer to run gdb in.
  if s:vertical
    vertical new
  else
    new
  endif
  let s:gdbwin = win_getid(winnr())
  let s:promptbuf = bufnr('')
  call prompt_setprompt(s:promptbuf, 'gdb> ')
  set buftype=prompt
  file gdb
  call prompt_setcallback(s:promptbuf, function('s:PromptCallback'))
  call prompt_setinterrupt(s:promptbuf, function('s:PromptInterrupt'))

  if s:vertical
    " Assuming the source code window will get a signcolumn, use two more
    " columns for that, thus one less for the terminal window.
    exe (&columns / 2 - 1) . "wincmd |"
  endif

  let gdb_args = get(a:dict, 'gdb_args', [])
  let proc_args = get(a:dict, 'proc_args', [])

  let gdb_cmd = s:GetCommand()
  " Add -quiet to avoid the intro message causing a hit-enter prompt.
  let gdb_cmd += ['-quiet']
  " Disable pagination, it causes everything to stop at the gdb, needs to be run early
  let gdb_cmd += ['-iex', 'set pagination off']
  " Interpret commands while the target is running.  This should usually only
  " be exec-interrupt, since many commands don't work properly while the
  " target is running (so execute during startup).
  let gdb_cmd += ['-iex', 'set mi-async on']
  " directly communicate via mi2
  let gdb_cmd += ['--interpreter=mi2']

  " Adding arguments requested by the user
  let gdb_cmd += gdb_args

  call ch_log('executing "' . join(gdb_cmd) . '"')
  let s:gdbjob = job_start(gdb_cmd, {
	\ 'exit_cb': function('s:EndPromptDebug'),
	\ 'out_cb': function('s:GdbOutCallback'),
	\ })
  if job_status(s:gdbjob) != "run"
    echoerr 'Failed to start gdb'
    exe 'bwipe! ' . s:promptbuf
    return
  endif
  " Mark the buffer modified so that it's not easy to close.
  set modified
  let s:gdb_channel = job_getchannel(s:gdbjob)

  let s:ptybuf = 0
  if has('win32')
    " MS-Windows: run in a new console window for maximum compatibility
    call s:SendCommand('set new-console on')
  elseif has('terminal')
    " Unix: Run the debugged program in a terminal window.  Open it below the
    " gdb window.
    belowright let s:ptybuf = term_start('NONE', {
	  \ 'term_name': 'debugged program',
	  \ })
    if s:ptybuf == 0
      echoerr 'Failed to open the program terminal window'
      call job_stop(s:gdbjob)
      return
    endif
    let s:ptywin = win_getid(winnr())
    let pty = job_info(term_getjob(s:ptybuf))['tty_out']
    call s:SendCommand('tty ' . pty)

    " Since GDB runs in a prompt window, the environment has not been set to
    " match a terminal window, need to do that now.
    call s:SendCommand('set env TERM = xterm-color')
    call s:SendCommand('set env ROWS = ' . winheight(s:ptywin))
    call s:SendCommand('set env LINES = ' . winheight(s:ptywin))
    call s:SendCommand('set env COLUMNS = ' . winwidth(s:ptywin))
    call s:SendCommand('set env COLORS = ' . &t_Co)
    call s:SendCommand('set env VIM_TERMINAL = ' . v:version)
  else
    " TODO: open a new terminal, get the tty name, pass on to gdb
    call s:SendCommand('show inferior-tty')
  endif
  call s:SendCommand('set print pretty on')
  call s:SendCommand('set breakpoint pending on')

  " Set arguments to be run
  if len(proc_args)
    call s:SendCommand('set args ' . join(proc_args))
  endif

  call s:StartDebugCommon(a:dict)
  startinsert
endfunc

func s:StartDebugCommon(dict)
  " Sign used to highlight the line where the program has stopped.
  " There can be only one.
  sign define debugPC linehl=debugPC

  " Install debugger commands in the text window.
  call win_gotoid(s:sourcewin)
  call s:InstallCommands()
  call win_gotoid(s:gdbwin)

  " Enable showing a balloon with eval info
  if has("balloon_eval") || has("balloon_eval_term")
    set balloonexpr=TermDebugBalloonExpr()
    if has("balloon_eval")
      set ballooneval
    endif
    if has("balloon_eval_term")
      set balloonevalterm
    endif
  endif

  " Contains breakpoints that have been placed, key is a string with the GDB
  " breakpoint number.
  " Each entry is a dict, containing the sub-breakpoints.  Key is the subid.
  " For a breakpoint that is just a number the subid is zero.
  " For a breakpoint "123.4" the id is "123" and subid is "4".
  " Example, when breakpoint "44", "123", "123.1" and "123.2" exist:
  " {'44': {'0': entry}, '123': {'0': entry, '1': entry, '2': entry}}
  let s:breakpoints = {}

  " Contains breakpoints by file/lnum.  The key is "fname:lnum".
  " Each entry is a list of breakpoint IDs at that position.
  let s:breakpoint_locations = {}

  augroup TermDebug
    au BufRead * call s:BufRead()
    au BufUnload * call s:BufUnloaded()
    au OptionSet background call s:Highlight(0, v:option_old, v:option_new)
  augroup END

  " Run the command if the bang attribute was given and got to the debug
  " window.
  if get(a:dict, 'bang', 0)
    call s:SendResumingCommand('-exec-run')
    call win_gotoid(s:ptywin)
  endif
endfunc

" Send a command to gdb.  "cmd" is the string without line terminator.
func s:SendCommand(cmd)
  call ch_log('sending to gdb: ' . a:cmd)
  if s:way == 'prompt'
    call ch_sendraw(s:gdb_channel, a:cmd . "\n")
  else
    call term_sendkeys(s:commbuf, a:cmd . "\r")
  endif
endfunc

" This is global so that a user can create their mappings with this.
func TermDebugSendCommand(cmd)
  if s:way == 'prompt'
    call ch_sendraw(s:gdb_channel, a:cmd . "\n")
  else
    let do_continue = 0
    if !s:stopped
      let do_continue = 1
      Stop
      sleep 10m
    endif
    call term_sendkeys(s:gdbbuf, a:cmd . "\r")
    if do_continue
      Continue
    endif
  endif
endfunc

" Send a command that resumes the program.  If the program isn't stopped the
" command is not sent (to avoid a repeated command to cause trouble).
" If the command is sent then reset s:stopped.
func s:SendResumingCommand(cmd)
  if s:stopped
    " reset s:stopped here, it may take a bit of time before we get a response
    let s:stopped = 0
    call ch_log('assume that program is running after this command')
    call s:SendCommand(a:cmd)
  else
    call ch_log('dropping command, program is running: ' . a:cmd)
  endif
endfunc

" Function called when entering a line in the prompt buffer.
func s:PromptCallback(text)
  call s:SendCommand(a:text)
endfunc

" Function called when pressing CTRL-C in the prompt buffer and when placing a
" breakpoint.
func s:PromptInterrupt()
  call ch_log('Interrupting gdb')
  if has('win32')
    " Using job_stop() does not work on MS-Windows, need to send SIGTRAP to
    " the debugger program so that gdb responds again.
    if s:pid == 0
      echoerr 'Cannot interrupt gdb, did not find a process ID'
    else
      call debugbreak(s:pid)
    endif
  else
    call job_stop(s:gdbjob, 'int')
  endif
endfunc

" Function called when gdb outputs text.
func s:GdbOutCallback(channel, text)
  call ch_log('received from gdb: ' . a:text)

  " Drop the gdb prompt, we have our own.
  " Drop status and echo'd commands.
  if a:text == '(gdb) ' || a:text == '^done' || a:text[0] == '&'
    return
  endif
  if a:text =~ '^\^error,msg='
    let text = s:DecodeMessage(a:text[11:])
    if exists('s:evalexpr') && text =~ 'A syntax error in expression, near\|No symbol .* in current context'
      " Silently drop evaluation errors.
      unlet s:evalexpr
      return
    endif
  elseif a:text[0] == '~'
    let text = s:DecodeMessage(a:text[1:])
  else
    call s:CommOutput(a:channel, a:text)
    return
  endif

  let curwinid = win_getid(winnr())
  call win_gotoid(s:gdbwin)

  " Add the output above the current prompt.
  call append(line('$') - 1, text)
  set modified

  call win_gotoid(curwinid)
endfunc

" Decode a message from gdb.  quotedText starts with a ", return the text up
" to the next ", unescaping characters:
" - remove line breaks
" - change \\t to \t
" - change \0xhh to \xhh (disabled for now)
" - change \ooo to octal
" - change \\ to \
func s:DecodeMessage(quotedText)
  if a:quotedText[0] != '"'
    echoerr 'DecodeMessage(): missing quote in ' . a:quotedText
    return
  endif
  return a:quotedText
        \ ->substitute('^"\|".*\|\\n', '', 'g')
        \ ->substitute('\\t', "\t", 'g')
        " multi-byte characters arrive in octal form
        " NULL-values must be kept encoded as those break the string otherwise
        \ ->substitute('\\000', s:NullRepl, 'g')
        \ ->substitute('\\\o\o\o', {-> eval('"' .. submatch(0) .. '"')}, 'g')
        " Note: GDB docs also mention hex encodings - the translations below work
        "       but we keep them out for performance-reasons until we actually see
        "       those in mi-returns
        " \ ->substitute('\\0x\(\x\x\)', {-> eval('"\x' .. submatch(1) .. '"')}, 'g')
        " \ ->substitute('\\0x00', s:NullRepl, 'g')
        \ ->substitute('\\\\', '\', 'g')
        \ ->substitute(s:NullRepl, '\\000', 'g')
endfunc
const s:NullRepl = 'XXXNULLXXX'

" Extract the "name" value from a gdb message with fullname="name".
func s:GetFullname(msg)
  if a:msg !~ 'fullname'
    return ''
  endif
  let name = s:DecodeMessage(substitute(a:msg, '.*fullname=', '', ''))
  if has('win32') && name =~ ':\\\\'
    " sometimes the name arrives double-escaped
    let name = substitute(name, '\\\\', '\\', 'g')
  endif
  return name
endfunc

" Extract the "addr" value from a gdb message with addr="0x0001234".
func s:GetAsmAddr(msg)
  if a:msg !~ 'addr='
    return ''
  endif
  let addr = s:DecodeMessage(substitute(a:msg, '.*addr=', '', ''))
  return addr
endfunc

func s:EndTermDebug(job, status)
  if exists('#User#TermdebugStopPre')
    doauto <nomodeline> User TermdebugStopPre
  endif

  exe 'bwipe! ' . s:commbuf
  unlet s:gdbwin

  call s:EndDebugCommon()
endfunc

func s:EndDebugCommon()
  let curwinid = win_getid(winnr())

  if exists('s:ptybuf') && s:ptybuf
    exe 'bwipe! ' . s:ptybuf
  endif

  " Restore 'signcolumn' in all buffers for which it was set.
  call win_gotoid(s:sourcewin)
  let was_buf = bufnr()
  for bufnr in s:signcolumn_buflist
    if bufexists(bufnr)
      exe bufnr .. "buf"
      if exists('b:save_signcolumn')
        let &signcolumn = b:save_signcolumn
        unlet b:save_signcolumn
      endif
    endif
  endfor
  exe was_buf .. "buf"

  call s:DeleteCommands()

  call win_gotoid(curwinid)

  if s:save_columns > 0
    let &columns = s:save_columns
  endif

  if has("balloon_eval") || has("balloon_eval_term")
    set balloonexpr=
    if has("balloon_eval")
      set noballooneval
    endif
    if has("balloon_eval_term")
      set noballoonevalterm
    endif
  endif

  if exists('#User#TermdebugStopPost')
    doauto <nomodeline> User TermdebugStopPost
  endif

  au! TermDebug
endfunc

func s:EndPromptDebug(job, status)
  if exists('#User#TermdebugStopPre')
    doauto <nomodeline> User TermdebugStopPre
  endif

  let curwinid = win_getid(winnr())
  call win_gotoid(s:gdbwin)
  set nomodified
  close
  if curwinid != s:gdbwin
    call win_gotoid(curwinid)
  endif

  call s:EndDebugCommon()
  unlet s:gdbwin
  call ch_log("Returning from EndPromptDebug()")
endfunc

" Disassembly window - added by Michael Sartain
"
" - CommOutput: disassemble $pc
" - CommOutput: &"disassemble $pc\n"
" - CommOutput: ~"Dump of assembler code for function main(int, char**):\n"
" - CommOutput: ~"   0x0000555556466f69 <+0>:\tpush   rbp\n"
" ...
" - CommOutput: ~"   0x0000555556467cd0:\tpop    rbp\n"
" - CommOutput: ~"   0x0000555556467cd1:\tret    \n"
" - CommOutput: ~"End of assembler dump.\n"
" - CommOutput: ^done

" - CommOutput: disassemble $pc
" - CommOutput: &"disassemble $pc\n"
" - CommOutput: &"No function contains specified address.\n"
" - CommOutput: ^error,msg="No function contains specified address."
func s:HandleDisasmMsg(msg)
  if a:msg =~ '^\^done'
    let curwinid = win_getid(winnr())
    if win_gotoid(s:asmwin)
      silent normal! gg0"_dG
      call setline(1, s:asm_lines)
      set nomodified
      set filetype=asm

      let lnum = search('^' . s:asm_addr)
      if lnum != 0
        exe 'sign unplace ' . s:asm_id
        exe 'sign place ' . s:asm_id . ' line=' . lnum . ' name=debugPC'
      endif

      call win_gotoid(curwinid)
    endif

    let s:parsing_disasm_msg = 0
    let s:asm_lines = []
  elseif a:msg =~ '^\^error,msg='
    if s:parsing_disasm_msg == 1
      " Disassemble call ran into an error. This can happen when gdb can't
      " find the function frame address, so let's try to disassemble starting
      " at current PC
      call s:SendCommand('disassemble $pc,+100')
    endif
    let s:parsing_disasm_msg = 0
  elseif a:msg =~ '\&\"disassemble \$pc'
    if a:msg =~ '+100'
      " This is our second disasm attempt
      let s:parsing_disasm_msg = 2
    endif
  else
    let value = substitute(a:msg, '^\~\"[ ]*', '', '')
    let value = substitute(value, '^=>[ ]*', '', '')
    let value = substitute(value, '\\n\"\r$', '', '')
    let value = substitute(value, '\\n\"$', '', '')
    let value = substitute(value, '\r', '', '')
    let value = substitute(value, '\\t', ' ', 'g')

    if value != '' || !empty(s:asm_lines)
      call add(s:asm_lines, value)
    endif
  endif
endfunc

" Handle a message received from gdb on the GDB/MI interface.
func s:CommOutput(chan, msg)
  let msgs = split(a:msg, "\r")

  for msg in msgs
    " remove prefixed NL
    if msg[0] == "\n"
      let msg = msg[1:]
    endif

    if s:parsing_disasm_msg
      call s:HandleDisasmMsg(msg)
    elseif msg != ''
      if msg =~ '^\(\*stopped\|\*running\|=thread-selected\)'
        call s:HandleCursor(msg)
      elseif msg =~ '^\^done,bkpt=' || msg =~ '^=breakpoint-created,'
        call s:HandleNewBreakpoint(msg, 0)
      elseif msg =~ '^=breakpoint-modified,'
        call s:HandleNewBreakpoint(msg, 1)
      elseif msg =~ '^=breakpoint-deleted,'
        call s:HandleBreakpointDelete(msg)
      elseif msg =~ '^=thread-group-started'
        call s:HandleProgramRun(msg)
      elseif msg =~ '^\^done,value='
        call s:HandleEvaluate(msg)
      elseif msg =~ '^\^error,msg='
        call s:HandleError(msg)
      elseif msg =~ '^disassemble'
        let s:parsing_disasm_msg = 1
        let s:asm_lines = []
      endif
    endif
  endfor
endfunc

func s:GotoProgram()
  if has('win32')
    if executable('powershell')
      call system(printf('powershell -Command "add-type -AssemblyName microsoft.VisualBasic;[Microsoft.VisualBasic.Interaction]::AppActivate(%d);"', s:pid))
    endif
  else
    call win_gotoid(s:ptywin)
  endif
endfunc

" Install commands in the current window to control the debugger.
func s:InstallCommands()
  let save_cpo = &cpo
  set cpo&vim

  command -nargs=? Break call s:SetBreakpoint(<q-args>)
  command Clear call s:ClearBreakpoint()
  command Step call s:SendResumingCommand('-exec-step')
  command Over call s:SendResumingCommand('-exec-next')
  command Finish call s:SendResumingCommand('-exec-finish')
  command -nargs=* Run call s:Run(<q-args>)
  command -nargs=* Arguments call s:SendResumingCommand('-exec-arguments ' . <q-args>)

  if s:way == 'prompt'
    command Stop call s:PromptInterrupt()
    command Continue call s:SendCommand('continue')
  else
    command Stop call s:SendCommand('-exec-interrupt')
    " using -exec-continue results in CTRL-C in the gdb window not working,
    " communicating via commbuf (= use of SendCommand) has the same result
    "command Continue  call s:SendCommand('-exec-continue')
    command Continue call term_sendkeys(s:gdbbuf, "continue\r")
  endif

  command -range -nargs=* Evaluate call s:Evaluate(<range>, <q-args>)
  command Gdb call win_gotoid(s:gdbwin)
  command Program call s:GotoProgram()
  command Source call s:GotoSourcewinOrCreateIt()
  command Asm call s:GotoAsmwinOrCreateIt()
  command Winbar call s:InstallWinbar()

  if !exists('g:termdebug_map_K') || g:termdebug_map_K
    let s:k_map_saved = maparg('K', 'n', 0, 1)
    nnoremap K :Evaluate<CR>
  endif

  if has('menu') && &mouse != ''
    call s:InstallWinbar()

    if !exists('g:termdebug_popup') || g:termdebug_popup != 0
      let s:saved_mousemodel = &mousemodel
      let &mousemodel = 'popup_setpos'
      an 1.200 PopUp.-SEP3-	<Nop>
      an 1.210 PopUp.Set\ breakpoint	:Break<CR>
      an 1.220 PopUp.Clear\ breakpoint	:Clear<CR>
      an 1.230 PopUp.Evaluate		:Evaluate<CR>
    endif
  endif

  let &cpo = save_cpo
endfunc

let s:winbar_winids = []

" Install the window toolbar in the current window.
func s:InstallWinbar()
  if has('menu') && &mouse != ''
    nnoremenu WinBar.Step   :Step<CR>
    nnoremenu WinBar.Next   :Over<CR>
    nnoremenu WinBar.Finish :Finish<CR>
    nnoremenu WinBar.Cont   :Continue<CR>
    nnoremenu WinBar.Stop   :Stop<CR>
    nnoremenu WinBar.Eval   :Evaluate<CR>
    call add(s:winbar_winids, win_getid(winnr()))
  endif
endfunc

" Delete installed debugger commands in the current window.
func s:DeleteCommands()
  delcommand Break
  delcommand Clear
  delcommand Step
  delcommand Over
  delcommand Finish
  delcommand Run
  delcommand Arguments
  delcommand Stop
  delcommand Continue
  delcommand Evaluate
  delcommand Gdb
  delcommand Program
  delcommand Source
  delcommand Asm
  delcommand Winbar

  if exists('s:k_map_saved')
    if empty(s:k_map_saved)
      nunmap K
    else
      call mapset('n', 0, s:k_map_saved)
    endif
    unlet s:k_map_saved
  endif

  if has('menu')
    " Remove the WinBar entries from all windows where it was added.
    let curwinid = win_getid(winnr())
    for winid in s:winbar_winids
      if win_gotoid(winid)
	aunmenu WinBar.Step
	aunmenu WinBar.Next
	aunmenu WinBar.Finish
	aunmenu WinBar.Cont
	aunmenu WinBar.Stop
	aunmenu WinBar.Eval
      endif
    endfor
    call win_gotoid(curwinid)
    let s:winbar_winids = []

    if exists('s:saved_mousemodel')
      let &mousemodel = s:saved_mousemodel
      unlet s:saved_mousemodel
      aunmenu PopUp.-SEP3-
      aunmenu PopUp.Set\ breakpoint
      aunmenu PopUp.Clear\ breakpoint
      aunmenu PopUp.Evaluate
    endif
  endif

  exe 'sign unplace ' . s:pc_id
  for [id, entries] in items(s:breakpoints)
    for subid in keys(entries)
      exe 'sign unplace ' . s:Breakpoint2SignNumber(id, subid)
    endfor
  endfor
  unlet s:breakpoints
  unlet s:breakpoint_locations

  sign undefine debugPC
  for val in s:BreakpointSigns
    exe "sign undefine debugBreakpoint" . val
  endfor
  let s:BreakpointSigns = []
endfunc

" :Break - Set a breakpoint at the cursor position.
func s:SetBreakpoint(at)
  " Setting a breakpoint may not work while the program is running.
  " Interrupt to make it work.
  let do_continue = 0
  if !s:stopped
    let do_continue = 1
    Stop
    sleep 10m
  endif

  " Use the fname:lnum format, older gdb can't handle --source.
  let at = empty(a:at) ?
	\ fnameescape(expand('%:p')) . ':' . line('.') : a:at
  call s:SendCommand('-break-insert ' . at)
  if do_continue
    Continue
  endif
endfunc

" :Clear - Delete a breakpoint at the cursor position.
func s:ClearBreakpoint()
  let fname = fnameescape(expand('%:p'))
  let lnum = line('.')
  let bploc = printf('%s:%d', fname, lnum)
  if has_key(s:breakpoint_locations, bploc)
    let idx = 0
    let nr = 0
    for id in s:breakpoint_locations[bploc]
      if has_key(s:breakpoints, id)
        " Assume this always works, the reply is simply "^done".
        call s:SendCommand('-break-delete ' . id)
        for subid in keys(s:breakpoints[id])
          exe 'sign unplace ' . s:Breakpoint2SignNumber(id, subid)
        endfor
        unlet s:breakpoints[id]
        unlet s:breakpoint_locations[bploc][idx]
        let nr = id
        break
      else
        let idx += 1
      endif
    endfor
    if nr != 0
      if empty(s:breakpoint_locations[bploc])
        unlet s:breakpoint_locations[bploc]
      endif
      echomsg 'Breakpoint ' . id . ' cleared from line ' . lnum . '.'
    else
      echoerr 'Internal error trying to remove breakpoint at line ' . lnum . '!'
    endif
  else
    echomsg 'No breakpoint to remove at line ' . lnum . '.'
  endif
endfunc

func s:Run(args)
  if a:args != ''
    call s:SendResumingCommand('-exec-arguments ' . a:args)
  endif
  call s:SendResumingCommand('-exec-run')
endfunc

func s:SendEval(expr)
  " check for "likely" boolean expressions, in which case we take it as lhs
  if a:expr =~ "[=!<>]="
    let exprLHS = a:expr
  else
    " remove text that is likely an assignment
    let exprLHS = substitute(a:expr, ' *=.*', '', '')
  endif

  " encoding expression to prevent bad errors
  let expr = a:expr
  let expr = substitute(expr, '\\', '\\\\', 'g')
  let expr = substitute(expr, '"', '\\"', 'g')
  call s:SendCommand('-data-evaluate-expression "' . expr . '"')
  let s:evalexpr = exprLHS
endfunc

" :Evaluate - evaluate what is specified / under the cursor
func s:Evaluate(range, arg)
  let expr = s:GetEvaluationExpression(a:range, a:arg)
  let s:ignoreEvalError = 0
  call s:SendEval(expr)
endfunc

" get what is specified / under the cursor
func s:GetEvaluationExpression(range, arg)
  if a:arg != ''
    " user supplied evaluation
    let expr = s:CleanupExpr(a:arg)
    " DSW: replace "likely copy + paste" assignment
    let expr = substitute(expr, '"\([^"]*\)": *', '\1=', 'g')
  elseif a:range == 2
    " no evaluation but provided but range set
    let pos = getcurpos()
    let reg = getreg('v', 1, 1)
    let regt = getregtype('v')
    normal! gv"vy
    let expr = s:CleanupExpr(@v)
    call setpos('.', pos)
    call setreg('v', reg, regt)
  else
    " no evaluation provided: get from C-expression under cursor
    " TODO: allow filetype specific lookup #9057
    let expr = expand('<cexpr>')
  endif
  return expr
endfunc

" clean up expression that may get in because of range
" (newlines and surrounding whitespace)
" As it can also be specified via ex-command for assignments this function
" may not change the "content" parts (like replacing contained spaces)
func s:CleanupExpr(expr)
  " replace all embedded newlines/tabs/...
  let expr = substitute(a:expr, '\_s', ' ', 'g')

  if &filetype ==# 'cobol'
    " extra cleanup for COBOL:
    " - a semicolon nmay be used instead of a space
    " - a trailing comma or period is ignored as it commonly separates/ends
    "   multiple expr
    let expr = substitute(expr, ';', ' ', 'g')
    let expr = substitute(expr, '[,.]\+ *$', '', '')
  endif

  " get rid of leading and trailing spaces
  let expr = substitute(expr, '^ *', '', '')
  let expr = substitute(expr, ' *$', '', '')
  return expr
endfunc

let s:ignoreEvalError = 0
let s:evalFromBalloonExpr = 0

" Handle the result of data-evaluate-expression
func s:HandleEvaluate(msg)
  let value = a:msg
    \ ->substitute('.*value="\(.*\)"', '\1', '')
    \ ->substitute('\\"', '"', 'g')
    \ ->substitute('\\\\', '\\', 'g')
    "\ multi-byte characters arrive in octal form, replace everything but NULL values
    \ ->substitute('\\000', s:NullRepl, 'g')
    \ ->substitute('\\\o\o\o', {-> eval('"' .. submatch(0) .. '"')}, 'g')
    "\ Note: GDB docs also mention hex encodings - the translations below work
    "\       but we keep them out for performance-reasons until we actually see
    "\       those in mi-returns
    "\ ->substitute('\\0x00', s:NullRep, 'g')
    "\ ->substitute('\\0x\(\x\x\)', {-> eval('"\x' .. submatch(1) .. '"')}, 'g')
    \ ->substitute(s:NullRepl, '\\000', 'g')
  if s:evalFromBalloonExpr
    if s:evalFromBalloonExprResult == ''
      let s:evalFromBalloonExprResult = s:evalexpr . ': ' . value
    else
      let s:evalFromBalloonExprResult .= ' = ' . value
    endif
    call balloon_show(s:evalFromBalloonExprResult)
  else
    echomsg '"' . s:evalexpr . '": ' . value
  endif

  if s:evalexpr[0] != '*' && value =~ '^0x' && value != '0x0' && value !~ '"$'
    " Looks like a pointer, also display what it points to.
    let s:ignoreEvalError = 1
    call s:SendEval('*' . s:evalexpr)
  else
    let s:evalFromBalloonExpr = 0
  endif
endfunc

" Show a balloon with information of the variable under the mouse pointer,
" if there is any.
func TermDebugBalloonExpr()
  if v:beval_winid != s:sourcewin
    return ''
  endif
  if !s:stopped
    " Only evaluate when stopped, otherwise setting a breakpoint using the
    " mouse triggers a balloon.
    return ''
  endif
  let s:evalFromBalloonExpr = 1
  let s:evalFromBalloonExprResult = ''
  let s:ignoreEvalError = 1
  let expr = s:CleanupExpr(v:beval_text)
  call s:SendEval(expr)
  return ''
endfunc

" Handle an error.
func s:HandleError(msg)
  if s:ignoreEvalError
    " Result of s:SendEval() failed, ignore.
    let s:ignoreEvalError = 0
    let s:evalFromBalloonExpr = 0
    return
  endif
  let msgVal = substitute(a:msg, '.*msg="\(.*\)"', '\1', '')
  echoerr substitute(msgVal, '\\"', '"', 'g')
endfunc

func s:GotoSourcewinOrCreateIt()
  if !win_gotoid(s:sourcewin)
    new
    let s:sourcewin = win_getid(winnr())
    call s:InstallWinbar()
  endif
endfunc

func s:GotoAsmwinOrCreateIt()
  if !win_gotoid(s:asmwin)
    if win_gotoid(s:sourcewin)
      exe 'rightbelow new'
    else
      exe 'new'
    endif

    let s:asmwin = win_getid(winnr())

    setlocal nowrap
    setlocal number
    setlocal noswapfile
    setlocal buftype=nofile
    setlocal modifiable

    let asmbuf = bufnr('Termdebug-asm-listing')
    if asmbuf > 0
      exe 'buffer' . asmbuf
    else
      exe 'file Termdebug-asm-listing'
    endif

    if exists('g:termdebug_disasm_window')
      if g:termdebug_disasm_window > 1
        exe 'resize ' . g:termdebug_disasm_window
      endif
    endif
  endif

  if s:asm_addr != ''
    let lnum = search('^' . s:asm_addr)
    if lnum == 0
      if s:stopped
        call s:SendCommand('disassemble $pc')
      endif
    else
      exe 'sign unplace ' . s:asm_id
      exe 'sign place ' . s:asm_id . ' line=' . lnum . ' name=debugPC'
    endif
  endif
endfunc

" Handle stopping and running message from gdb.
" Will update the sign that shows the current position.
func s:HandleCursor(msg)
  let wid = win_getid(winnr())

  if a:msg =~ '^\*stopped'
    call ch_log('program stopped')
    let s:stopped = 1
  elseif a:msg =~ '^\*running'
    call ch_log('program running')
    let s:stopped = 0
  endif

  if a:msg =~ 'fullname='
    let fname = s:GetFullname(a:msg)
  else
    let fname = ''
  endif

  if a:msg =~ 'addr='
    let asm_addr = s:GetAsmAddr(a:msg)
    if asm_addr != ''
      let s:asm_addr = asm_addr

      let curwinid = win_getid(winnr())
      if win_gotoid(s:asmwin)
        let lnum = search('^' . s:asm_addr)
        if lnum == 0
          call s:SendCommand('disassemble $pc')
        else
          exe 'sign unplace ' . s:asm_id
          exe 'sign place ' . s:asm_id . ' line=' . lnum . ' name=debugPC'
        endif

        call win_gotoid(curwinid)
      endif
    endif
  endif

  if a:msg =~ '^\(\*stopped\|=thread-selected\)' && filereadable(fname)
    let lnum = substitute(a:msg, '.*line="\([^"]*\)".*', '\1', '')
    if lnum =~ '^[0-9]*$'
      call s:GotoSourcewinOrCreateIt()
      if expand('%:p') != fnamemodify(fname, ':p')
echomsg 'different fname: "' .. expand('%:p') .. '" vs "' .. fnamemodify(fname, ':p') .. '"'
	augroup Termdebug
	  " Always open a file read-only instead of showing the ATTENTION
	  " prompt, since we are unlikely to want to edit the file.
	  " The file may be changed but not saved, warn for that.
	  au SwapExists * echohl WarningMsg
		\ | echo 'Warning: file is being edited elsewhere'
		\ | echohl None
		\ | let v:swapchoice = '0'
        augroup END
        if &modified
          " TODO: find existing window
          exe 'split ' . fnameescape(fname)
          let s:sourcewin = win_getid(winnr())
          call s:InstallWinbar()
        else
          exe 'edit ' . fnameescape(fname)
        endif
        augroup Termdebug
          au! SwapExists
        augroup END
      endif
      exe lnum
      normal! zv
      exe 'sign unplace ' . s:pc_id
      exe 'sign place ' . s:pc_id . ' line=' . lnum . ' name=debugPC priority=110 file=' . fname
      if !exists('b:save_signcolumn')
        let b:save_signcolumn = &signcolumn
        call add(s:signcolumn_buflist, bufnr())
      endif
      setlocal signcolumn=yes
    endif
  elseif !s:stopped || fname != ''
    exe 'sign unplace ' . s:pc_id
  endif

  call win_gotoid(wid)
endfunc

let s:BreakpointSigns = []

func s:CreateBreakpoint(id, subid, enabled)
  let nr = printf('%d.%d', a:id, a:subid)
  if index(s:BreakpointSigns, nr) == -1
    call add(s:BreakpointSigns, nr)
    if a:enabled == "n"
      let hiName = "debugBreakpointDisabled"
    else
      let hiName = "debugBreakpoint"
    endif
    exe "sign define debugBreakpoint" . nr . " text=" . substitute(nr, '\..*', '', '') . " texthl=" . hiName
  endif
endfunc

func! s:SplitMsg(s)
  return split(a:s, '{.\{-}}\zs')
endfunction

" Handle setting a breakpoint
" Will update the sign that shows the breakpoint
func s:HandleNewBreakpoint(msg, modifiedFlag)
  if a:msg !~ 'fullname='
    " a watch or a pending breakpoint does not have a file name
    if a:msg =~ 'pending='
      let nr = substitute(a:msg, '.*number=\"\([0-9.]*\)\".*', '\1', '')
      let target = substitute(a:msg, '.*pending=\"\([^"]*\)\".*', '\1', '')
      echomsg 'Breakpoint ' . nr . ' (' . target  . ') pending.'
    endif
    return
  endif
  for msg in s:SplitMsg(a:msg)
    let fname = s:GetFullname(msg)
    if empty(fname)
      continue
    endif
    let nr = substitute(msg, '.*number="\([0-9.]*\)\".*', '\1', '')
    if empty(nr)
      return
    endif

    " If "nr" is 123 it becomes "123.0" and subid is "0".
    " If "nr" is 123.4 it becomes "123.4.0" and subid is "4"; "0" is discarded.
    let [id, subid; _] = map(split(nr . '.0', '\.'), 'v:val + 0')
    let enabled = substitute(msg, '.*enabled="\([yn]\)".*', '\1', '')
    call s:CreateBreakpoint(id, subid, enabled)

    if has_key(s:breakpoints, id)
      let entries = s:breakpoints[id]
    else
      let entries = {}
      let s:breakpoints[id] = entries
    endif
    if has_key(entries, subid)
      let entry = entries[subid]
    else
      let entry = {}
      let entries[subid] = entry
    endif

    let lnum = substitute(msg, '.*line="\([^"]*\)".*', '\1', '')
    let entry['fname'] = fname
    let entry['lnum'] = lnum

    let bploc = printf('%s:%d', fname, lnum)
    if !has_key(s:breakpoint_locations, bploc)
      let s:breakpoint_locations[bploc] = []
    endif
    let s:breakpoint_locations[bploc] += [id]

    if bufloaded(fname)
      call s:PlaceSign(id, subid, entry)
      let posMsg = ' at line ' . lnum . '.'
    else
      let posMsg = ' in ' . fname . ' at line ' . lnum . '.'
    endif
    if !a:modifiedFlag
      let actionTaken = 'created'
    elseif enabled == 'n'
      let actionTaken = 'disabled'
    else
      let actionTaken = 'enabled'
    endif
    echomsg 'Breakpoint ' . nr . ' ' . actionTaken . posMsg
  endfor
endfunc

func s:PlaceSign(id, subid, entry)
  let nr = printf('%d.%d', a:id, a:subid)
  exe 'sign place ' . s:Breakpoint2SignNumber(a:id, a:subid) . ' line=' . a:entry['lnum'] . ' name=debugBreakpoint' . nr . ' priority=110 file=' . a:entry['fname']
  let a:entry['placed'] = 1
endfunc

" Handle deleting a breakpoint
" Will remove the sign that shows the breakpoint
func s:HandleBreakpointDelete(msg)
  let id = substitute(a:msg, '.*id="\([0-9]*\)\".*', '\1', '') + 0
  if empty(id)
    return
  endif
  if has_key(s:breakpoints, id)
    for [subid, entry] in items(s:breakpoints[id])
      if has_key(entry, 'placed')
        exe 'sign unplace ' . s:Breakpoint2SignNumber(id, subid)
        unlet entry['placed']
      endif
    endfor
    unlet s:breakpoints[id]
    echomsg 'Breakpoint ' . id . ' cleared.'
  endif
endfunc

" Handle the debugged program starting to run.
" Will store the process ID in s:pid
func s:HandleProgramRun(msg)
  let nr = substitute(a:msg, '.*pid="\([0-9]*\)\".*', '\1', '') + 0
  if nr == 0
    return
  endif
  let s:pid = nr
  call ch_log('Detected process ID: ' . s:pid)
endfunc

" Handle a BufRead autocommand event: place any signs.
func s:BufRead()
  let fname = expand('<afile>:p')
  for [id, entries] in items(s:breakpoints)
    for [subid, entry] in items(entries)
      if entry['fname'] == fname
        call s:PlaceSign(id, subid, entry)
      endif
    endfor
  endfor
endfunc

" Handle a BufUnloaded autocommand event: unplace any signs.
func s:BufUnloaded()
  let fname = expand('<afile>:p')
  for [id, entries] in items(s:breakpoints)
    for [subid, entry] in items(entries)
      if entry['fname'] == fname
        let entry['placed'] = 0
      endif
    endfor
  endfor
endfunc

let &cpo = s:keepcpo
unlet s:keepcpo