youcompleteme and finding h files

Question

I've got an embedded project I'm doing and I'd like to use Vim and YCM to do it. I've got the following code as a quick prototype:

#include <avr/io.h>

#define USART_BAUDRATE 9600
#define BAUD_PRESCALE (((F_CPU/(USART_BAUDRATE*16UL)))-1)

int main(void){
 char recieved_byte;

 UCSR0B |= (1<<RXEN0)  | (1<<TXEN0);
 UCSR0C |= (1<<UCSZ00) | (1<<UCSZ01);
 UBRR0H  = (BAUD_PRESCALE >> 8);
 UBRR0L  = BAUD_PRESCALE;

    for(;;){
  // wait until a byte is ready to read
  while( ( UCSR0A & ( 1 << RXC0 ) ) == 0 ){}

  // grab the byte from the serial port
  recieved_byte = UDR0;

  // wait until the port is ready to be written to
  while( ( UCSR0A & ( 1 << UDRE0 ) ) == 0 ){}

  // write the byte to the serial port
  UDR0 = recieved_byte;
    }
    return 0;   /* never reached */
}

and I've got this for a `.ycm_extra_conf.py

import os
import ycm_core
from clang_helpers import PrepareClangFlags

# Set this to the absolute path to the folder (NOT the file!) containing the
# compile_commands.json file to use that instead of 'flags'. See here for
# more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
# Most projects will NOT need to set this to anything; you can just change the
# 'flags' list of compilation flags. Notice that YCM itself uses that approach.
compilation_database_folder = ''

# These are the compilation flags that will be used in case there's no
# compilation database set.
flags = [
'-D__AVR_ATtiny167__',
# THIS IS IMPORTANT! Without a "-std=<something>" flag, clang won't know which
# language to use when compiling headers. So it will guess. Badly. So C++
# headers will be compiled as C headers. You don't want that so ALWAYS specify
# a "-std=<something>".
# For a C project, you would set this to something like 'c99' instead of
# 'c++11'.
'-std=c99',
# ...and the same thing goes for the magic -x option which specifies the
# language that the files to be compiled are written in. This is mostly
# relevant for c++ headers.
# For a C project, you would set this to 'c' instead of 'c++'.
'-isystem',
'/usr/avr/include/avr',
'/usr/avr/include/',
'-isystem',
'/usr/local/avr/include',
'/usr/local/avr/',
'-DF_CPU=16000000UL',
'-DARCH=ARCH_ATTINY',
'-DF_USB=16000000',
'-DBOARD=BOARD_NONE',
'-DFLASH_SIZE_BYTES=128000',
'-DBOOTLOADER_SEC_SIZE_BYTES=8192',
'-DUSB_DEVICE_ONLY',
'-DNO_STREAM_CALLBACKS',
'-DINTERRUPT_CONTROL_ENDPOINT',
'-DUSE_FLASH_DESCRIPTORS',
'-DUSE_STATIC_OPTIONS="(USB_DEVICE_OPT_FULLSPEED | USB_OPT_PLLCLKSRC)"',
'-DFIXED_CONTROL_ENDPOINT_SIZE=32',
'-DFIXED_NUM_CONFIGURATIONS=1',
'-DMPU9150',
'-Os',
'-funsigned-char',
'-fpack-struct',
'-fshort-enums',
'-Wall',
'-Wstrict-prototypes',
'-I',
'.',
'-I',
'./XMEGA/',
'-I', 'include',
'-I.',
# This path is for AVR gcc. 
]

if compilation_database_folder:
  database = ycm_core.CompilationDatabase( compilation_database_folder )
else:
  database = None


def DirectoryOfThisScript():
  return os.path.dirname( os.path.abspath( __file__ ) )


def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
  if not working_directory:
    return flags
  new_flags = []
  make_next_absolute = False
  path_flags = [ '-isystem', '-I', '-iquote', '--sysroot=' ]
  for flag in flags:
    new_flag = flag

    if make_next_absolute:
      make_next_absolute = False
      if not flag.startswith( '/' ):
        new_flag = os.path.join( working_directory, flag )

    for path_flag in path_flags:
      if flag == path_flag:
        make_next_absolute = True
        break

      if flag.startswith( path_flag ):
        path = flag[ len( path_flag ): ]
        new_flag = path_flag + os.path.join( working_directory, path )
        break

    if new_flag:
      new_flags.append( new_flag )
  return new_flags


def FlagsForFile( filename ):
  if database:
    # Bear in mind that compilation_info.compiler_flags_ does NOT return a
    # python list, but a "list-like" StringVec object
    compilation_info = database.GetCompilationInfoForFile( filename )
    final_flags = PrepareClangFlags(
        MakeRelativePathsInFlagsAbsolute(
            compilation_info.compiler_flags_,
            compilation_info.compiler_working_dir_ ),
        filename )

  else:
    relative_to = DirectoryOfThisScript()
    final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )

  return {
    'flags': final_flags,
    'do_cache': True
  }

`

The problem is that when editing the file, every single instance of an AVR register (which I thought was defined in avr/io.h and it's subsequent location was referenced in the .ycm_extra_conf.py file) is being flagged as an undeclared identifier.

I'm using Arch Linux and am programming an ATMega328p.

What am I doing wrong?

pay attention to your flags. Example of one issue, you're doing `'-isystem', '/usr/local/avr/include', '/usr/local/avr/'`. Here you have two directories in sequence. Each include directory must be preceeded by the include flag, and generally you should use `-I`, not `-system` for everything. This is just one problem, there may be more. — oblitum, Jul 02 '16 at 06:21
I have never seen/used multiple directories for a single include flag being used with compilers. So I'm not sure it works, I just know what has always worked for me. — oblitum, Jul 02 '16 at 17:58
`-DARCH=ARCH_ATTINY` looks wrong - the part is a ATMega not an ATTiny. Are these macros from a different project? You should fix that - it needs to match the actual build. — Clifford, Jul 02 '16 at 22:42
Very good, thank you. This is very confusing in that , yes, there is a lot of documentation,but you don't know what you don't know. I will look into that further. — testname123, Jul 03 '16 at 03:02
Did you ever get this to work? I'm struggling with it right now. — Yankee, Jul 05 '17 at 03:13
Yes...Cliffords advice was correct, but I had another issue...I left off the period in the ycm_extra_conf.py — testname123, Aug 23 '17 at 20:48

Clifford · Answer 1 · 2016-07-02T22:27:36.530

0

io.h includes conditional compilation to select specific AVR parts. Your pre-processor macros list (-D... options) does not include __AVR_ATmega328P__ so the code parser excludes all the necessary part specific declarations, just as the pre-processor would is the macro did not exist.

As well as you own project definitions, you should set any that are defined by the compiler or build system.

edited Jul 02 '16 at 22:27

answered Jul 02 '16 at 10:24

Clifford

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I see...Where are all these possible directives listed? Where could I have found out on my own that __AVR_ATmega328P__ is a valid option for there? – testname123 Jul 02 '16 at 12:21
@BrocolliRob : I looked in [io.h](http://www.nongnu.org/avr-libc/user-manual/io_8h_source.html), and observed the conditional compilation - it is not VIM/YCM specific. You can see the command-line defined macros for your build simply by observing the build log. For GCC internally pre-defined macros can be dumped as shown [here](http://stackoverflow.com/questions/2224334/gcc-dump-preprocessor-defines) - some are determined by other compiler options, so include all used by your project to get an accurate list. – Clifford Jul 02 '16 at 22:32

youcompleteme and finding h files

1 Answers1