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Build instruction for Debian 11/Bullseye and 12/Bookworm arm64/aarch64
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Add LLVM/Clang 18 repository under su to file /etc/apt/sources.list.d/llvm18.list:
If using Debian 11/Bullseye:
$ su -
# echo -e "deb [trusted=yes] http://apt.llvm.org/bullseye/ llvm-toolchain-bullseye-18 main \ndeb-src [trusted=yes] http://apt.llvm.org/bullseye/ llvm-toolchain-bullseye-18 main" >> /etc/apt/sources.list.d/llvm18.list

If using Debian 12/Bookworm:
$ su -
# echo -e "deb [trusted=yes] http://apt.llvm.org/bookworm/ llvm-toolchain-bookworm-18 main \ndeb-src [trusted=yes] http://apt.llvm.org/bookworm/ llvm-toolchain-bookworm-18 main" >> /etc/apt/sources.list.d/llvm18.list


Proceed to apt update and install necessary packages. E.g. clang-18 clang-tools-18 llvm-18 libclang-rt-18-dev 


Leave su and return to "user mode":
# exit


Download neural-amp-modeler-lv2 source code and enter the build directory:
$ cd /tmp && git clone --recurse-submodules -j4 https://github.com/mikeoliphant/neural-amp-modeler-lv2 && cd neural-amp-modeler-lv2/build


Export Clang 18 flags/parameters (compile with -Og) and then compile:
$ export CC=clang-18 && export CXX=clang++-18 && export LD=lld-18 && export CFLAGS="-Og -fprofile-generate=/tmp/neural-amp-modeler-lv2/build" && export CXXFLAGS="-Og -fprofile-generate=/tmp/neural-amp-modeler-lv2/build" && export LDFLAGS="-Og -fprofile-generate=/tmp/neural-amp-modeler-lv2/build"
$ cmake .. && make


- Copy the created "neural_amp_modeler.lv2" folder to ~/.lv2/
- Run the plugin with your LV2 host of choice and try load several models with different activators, algorithms, settings, etc and adjust sliders randomly.
- Close the plugin/host

A .profraw file has been created in /tmp/neural-amp-modeler-lv2/build/


Go back to build directory and convert the .profraw data to "profile.profdata":
$ cd /tmp/neural-amp-modeler-lv2/build/
$ llvm-profdata-18 merge -output profile.profdata RENAMETOACTUALFILENAME.profraw


Remove all files in /tmp/neural-amp-modeler-lv2/build/ EXCEPT for profile.profdata .


Compile with optimized flags/parameters:
$ export CC=clang-18 && export CXX=clang++-18 && export LD=lld-18 && export CFLAGS="-Ofast -flto=thin -fopenacc -fopenmp -march=native -fprofile-use=/tmp/neural-amp-modeler-lv2/build/profile.profdata" && export CXXFLAGS="-Ofast -flto=thin -fopenacc -fopenmp -march=native -fprofile-use=/tmp/neural-amp-modeler-lv2/build/profile.profdata" && export LDFLAGS="-Ofast -flto=thin -fopenacc -fopenmp -march=native -fprofile-use=/tmp/neural-amp-modeler-lv2/build/profile.profdata"
$ cmake .. -DBUILD_SHARED_LIBS=0 && make

Move newly compiled optimized files and folder neural_amp_modeler.lv2 to directory ~/.lv2/ . Replace old files.

Now you should have the following files:

~/.lv2/neural_amp_modeler.lv2/manifest.ttl
~/.lv2/neural_amp_modeler.lv2/neural_amp_modeler.so
~/.lv2/neural_amp_modeler.lv2/neural_amp_modeler.ttl

UPDATE 20240823: Removed "-DCMAKE_BUILD_TYPE=Release" from cmake command. Changed -O3 to -Ofast. Added -fopenmp -march=native

// R Gerthsson