Makefiles in sPyNNaker version 5.0.0

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The way the C code is built was changed in April 2018.

These changes have required major modifications to the make files, and moving many C and makefiles.

Background

To save ITCM memory the way log messages are handled has been changed.

Instead of using strings in log messages a Dictionary coder is now used.

To avoid every developer having to have the dictionary and making sure to use the correct message number this substitution is now done automatically at compile time.

This conversion is done by the makefiles who now call spinn_utilities.make_tools.converter to convert C files from the src directory into a modified_src directory before building. The tool also creates *.dict files to record the mappings as well as *.range files to keep the number unique in each parts of the code.

Each log message is changed to a log_mini method where the message string is replaced by a number. For example: log_info(“Reading parameters from 0x%.8x”, region_address); becomes log_mini_info(12345, region_address);

The conversion from message IDs back to the full string is done automatically by spinn_utilities.make_tools.replacer, called from spinn_front_end_common/interface/interface_functions/chip_iobuf_extractor.py.

Future_work

The log_mini_ methods currently still use fprintf and record number IDs and values in string format. This may be replaced with a save in numerical format instead to save even more iobuf space, and possibly allow more data types to be logged.

Limitations

The converter expects the first parameter in each log message to be a pure string.

As a string parameter can be passed in using as a variable using %s for example: Instead of: log_info(msg); do: log_info(“%s”, msg);

Location of files

The C files have now been split into 4 sections

src

All the raw C files have been moved into src directories (unless already in a src directory). The only files in the src directory and its children should be compilable C files (*.c and *.h) (ignoring any .gitignore files).

makefiles

Each root makefile is now at the same level as their src directory or in a makefile directly parallel to their src directory.

modified_src

This is where the makefiles will place the converted C files. This is done automatically, and these directories are deleted by “make clean” so do not edit them.

build

This is where temporary files used during make are placed. In the sPynnaker repository build is no longer a subdirectory of src. This includes *.o object files, *.bin, *.elf ect. These directories are deleted by “make clean” so do not add anything you hope to keep.

Changes to the C files

includes

All .. include paths have been removed! Instead they have been replaced by full paths back to NEURAL_MODELLING_DIRS/src or the equivalent. This allows for the modified files to be easily found using -I NEURAL_MODELLING_DIRS/modified_src

Other C changes

The only other C file changes is in neuron/structural_plasticity/synaptogenesis/topographic_map_impl.c, where the DMA_WRITEBACK method has been changed (See limitations).

Makefiles

spinnaker_tools.mk

This is the root make file for nearly all the make files.

It contains the main instuctions for building spinnaker C files into object files, then elf files, then bin and md files and finally aplx files.

This is a nearly like for like replacement of spinnaker_tools/make/Makefile.common

local.mk

This is used for all builds where the c files are local to the make file. This covers most cases that do NOT depend on NEURAL_MODELLING_DIRS/src/neuron, and includes the relative stuff previously in Makefile.FrontEndCommon or FrontEndCommon.mk.

This requires 3 variables to be set before being called:

  1. APP: the name of the application, which is used to name the aplx and dict files.
  2. SOURCES: the list of files to build.
  3. APP_OUTPUT_DIR: the location where the aplx and dict files will be placed.

Optionally extra variables are; SOURCE_DIRS: defaults to src/ at the same level as the makefile BUILD_DIR: defaults to build/ at the same level as the makefile

It is also possible in your application’s makefile to add to the compiler / library flags by adding to the CFLAGS / LFLAGS variables (e.g. CFLAGS += …) as appropriate.

Muiltple make files can be in the same directory, sharing the same src and build directories as long as they define a different APP. The code will be modifed once by the make_converter unless it is changed between builds.

neural_build.mk

This is used for Neuron builds etc. that do depend on NEURAL_MODELLING_DIRS/src/neuron.

It includes the relative stuff previously in FrontEndCommon.mk, paths.mk and sPyNNaker/neural_modelling/src/neuron/builds/common.mk

Neurons are built by linking together various bits of C code defined in the variables

  • NEURON_IMPL
  • NEURON_IMPL_H
  • NEURON_MODEL
  • NEURON_MODEL_H
  • INPUT_TYPE_H
  • THRESHOLD_TYPE_H
  • SYNAPSE_TYPE_H
  • SYNAPSE_DYNAMICS

Plus the following optional variables:

  • ADDITIONAL_INPUT_H
  • WEIGHT_DEPENDENCE
  • TIMING_DEPENDENCE
  • SYNAPTOGENESIS_DYNAMICS

These should all be defined based on the variable

  • NEURON_DIR (which points to $(NEURAL_MODELLING_DIRS)/src/)
    • For historical reasons, SOURCE_DIR is also set but its use is not encouraged.

If the C sources are not all in NEURAL_MODELLING_DIRS/src then see sPyNNaker8NewModelTemplate and in particular sPyNNaker8NewModelTemplate/c_models/makefiles/my_neuron_modelling_build.mk for an example.

The standard variables are all defined in NEURAL_MODELLING_DIRS/makefiles/neural_support.mk.

The following variables are also needed but have default values

  • BUILD_DIR defaults to $(NEURAL_MODELLING_DIRS)/builds/$(APP)/
    • Each individual build MUST have a unique build directory due to the complex linking.
  • APP_OUTPUT_DIR defaults to:= $(abspath $(NEURAL_MODELLING_DIRS)/../spynnaker/pyNN/model_binaries)/

Internally the paths are changed to ones based on:

  • MODIFIED_DIR := $(NEURAL_MODELLING_DIRS)/modified_src

All the make rules required to modify the C code and build the dict files are provided.

sPyNNaker8NewModelTemplate/c_models/makefiles/my_neuron_modelling_build.mk

This is an example file of how to use multiple source directories and still build using neurons.

Documentation has been include in the makefile itself.

Other makefiles

Many of the previous shared makefiles are no longer used.

They have been converted to just throwing an error and pointing here.

Please contact the SpiNNaker software team (idealy via the googlegroup) if you need help converting previous makefiles.

Dict Files

The makefiles generate a APP_OUTPUT_DIR/APP.dict file next to each APP_OUTPUT_DIR/APP.aplx file.

The purpose of these files is to supply the dictionary mapping for the log messages so that they can be correctly converted back.

These hold the mappings as they where at the time the aplx file was created. If the sources have changed and partially rebuilt since the aplx file was committed they may not match the files in the modified directories.

Whole C code directories are converted in a single call. This approach was chosen as it avoids having to track exactly which files are included. It also allows the modified code to be re-used for several builds. Log levels are ignored as they could be different between builds. Therefore the dict files will include more classes and messages than actualy used in the code. As they list by log message and not by C file, files with no log statements will not be included, but will have been converted into the modified directories. So, the dict files can not be considered a listing of what C files were used, or what messages could be logged.

SPINN_DIRS/lib/log.ranges

This file is automatically generated, used and deleted by clean-install so you need not worry about it. What is does do is make sure that each modified directory has a unique range of numbers to use. As long as all your directories have a shared root this file will just list based on that shared root.