Build Failure on Termux with LLVM 20 due to find_package incompatibility #1328
Description
This is an update to the situation first described in #1061.
Problem
With llvmlite now requiring LLVM 20, the previous workaround of using LLVM 14 is no longer valid. Attempting to build llvmlite from source on Termux with the system-provided LLVM 20 fails during the CMake configuration step.
Root Cause
The build fails because llvmlite uses the standard find_package(LLVM REQUIRED CONFIG) command. This fails on Termux because the libllvm-20 package contains a faulty CMake manifest (LLVMExports.cmake) that incorrectly defines and requires a static library (libLLVMCGData.a) that doesn't exist in the shared-only package.
Successful Workaround
A successful build was achieved by modifying ffi/CMakeLists.txt to bypass the faulty find_package command and use the llvm-config-20 tool directly.
1. Patch ffi/CMakeLists.txt:
Replace the line find_package(LLVM REQUIRED CONFIG) with the following block:
# --- Start of llvm-config patch ---
# Use llvm-config to bypass the faulty CMake export files.
find_program(LLVM_CONFIG_EXECUTABLE llvm-config-20 HINTS /data/data/com.termux/files/usr/bin)
if(NOT LLVM_CONFIG_EXECUTABLE)
message(FATAL_ERROR "llvm-config-20 not found! Please ensure it is in your PATH.")
endif()
# Get version for the version check
execute_process(COMMAND ${LLVM_CONFIG_EXECUTABLE} --version OUTPUT_VARIABLE LLVM_PACKAGE_VERSION OUTPUT_STRIP_TRAILING_WHITESPACE)
string(REGEX MATCH "([0-9]+)" LLVM_VERSION_MAJOR "${LLVM_PACKAGE_VERSION}")
# Get include dirs and definitions
execute_process(COMMAND ${LLVM_CONFIG_EXECUTABLE} --cxxflags OUTPUT_VARIABLE LLVM_CXX_FLAGS OUTPUT_STRIP_TRAILING_WHITESPACE)
string(REGEX MATCHALL "-I[^ ]+" LLVM_INCLUDE_DIRS_RAW "${LLVM_CXX_FLAGS}")
foreach(dir ${LLVM_INCLUDE_DIRS_RAW})
string(REPLACE "-I" "" dir_stripped ${dir})
list(APPEND LLVM_INCLUDE_DIRS ${dir_stripped})
endforeach()
string(REGEX MATCHALL "-D[^ ]+" LLVM_DEFINITIONS "${LLVM_CXX_FLAGS}")
# Get the main shared library for linking
execute_process(COMMAND ${LLVM_CONFIG_EXECUTABLE} --link-shared --libs OUTPUT_VARIABLE llvm_libs OUTPUT_STRIP_TRAILING_WHITESPACE)
# --- End of llvm-config patch ---2. Build Command:
After applying the patch and ensuring a clean build directory, the installation was successful with the following command:
LLVMLITE_SHARED=ON LLVMLITE_USE_RTTI=OFF pip install . -U --force-reinstallClean Build Log
Looking in indexes: https://pypi.org/simple, https://download.pytorch.org/whl/cpu
Processing /data/data/com.termux/files/home/Downloads/GitHub/llvmlite
Preparing metadata (setup.py): started
Preparing metadata (setup.py): finished with status 'done'
Building wheels for collected packages: llvmlite
Building wheel for llvmlite (setup.py): started
Building wheel for llvmlite (setup.py): finished with status 'done'
Created wheel for llvmlite: filename=llvmlite-0.46.0b1+14.g7c0e103.dirty-cp312-cp312-linux_aarch64.whl size=1602828 sha256=a77af22e420d0091c882d05d7e165923241386e46fc33d4b0d5ca1c33e835245
Stored in directory: /data/data/com.termux/files/usr/tmp/pip-ephem-wheel-cache-q1687gvq/wheels/c0/2e/9e/8fb4cf2bfad383accfc8ef3cdfae92204801101f334763f467
Successfully built llvmlite
Installing collected packages: llvmlite
Successfully installed llvmlite-0.46.0b1+14.g7c0e103.dirty
Suggestion
It might be beneficial for llvmlite's build system to have a fallback or an explicit option to use llvm-config instead of find_package. This would make it more robust against packaging issues like the one found in the Termux libllvm-20 package.