[Other Questions] The LLVM shared library ("libLLVM.so") could not be found

[gritk]

Summary

Usage of mitsuba failed

System configuration

System information:

Platform: Ubuntu 20.04.5 LTS
Python version: 3.8.13 (miniconda)
Mitsuba 3 version: lateset

Description

# Import the library using the alias "mi"
import mitsuba as mi
# Set the variant of the renderer
mi.set_variant('scalar_rgb')
# Load a scene
scene = mi.load_dict(mi.cornell_box())
# Render the scene
img = mi.render(scene)
# Write the rendered image to an EXR file
mi.Bitmap(img).write('cbox.exr')

Rendering (9.14s, ETA: 0ms)
jit_llvm_init(): no suitable vector ISA found, shutting down LLVM backend..


import mitsuba as mi
# Set the variant of the renderer
mi.set_variant('llvm_ad_rgb')

jit_llvm_init(): no suitable vector ISA found, shutting down LLVM backend..

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
File ~/eradiate/build/ext/mitsuba/python/mitsuba/__init__.py:115, in MitsubaVariantModule.__getattribute__(self, key)
    112 try:
    113     modules = (
    114         _import('mitsuba.mitsuba_ext'),
--> 115         _import('mitsuba.mitsuba_' + variant + '_ext'),
    116     )
    117     super().__setattr__('_modules', modules)

File ~/miniconda3/envs/mitsuba/lib/python3.8/importlib/__init__.py:127, in import_module(name, package)
    126         level += 1
--> 127 return _bootstrap._gcd_import(name[level:], package, level)

File <frozen importlib._bootstrap>:1014, in _gcd_import(name, package, level)

File <frozen importlib._bootstrap>:991, in _find_and_load(name, import_)

File <frozen importlib._bootstrap>:975, in _find_and_load_unlocked(name, import_)

File <frozen importlib._bootstrap>:657, in _load_unlocked(spec)

File <frozen importlib._bootstrap>:556, in module_from_spec(spec)

File <frozen importlib._bootstrap_external>:1166, in create_module(self, spec)

File <frozen importlib._bootstrap>:219, in _call_with_frames_removed(f, *args, **kwds)

ImportError: jit_init_thread_state(): the LLVM backend is inactive because the LLVM shared library ("libLLVM.so") could not be found! Set the DRJIT_LIBLLVM_PATH environment variable to specify its path.

During handling of the above exception, another exception occurred:

AttributeError                            Traceback (most recent call last)
Input In [3], in <cell line: 3>()
      1 import mitsuba as mi
      2 # Set the variant of the renderer
----> 3 mi.set_variant('llvm_ad_rgb')

File ~/eradiate/build/ext/mitsuba/python/mitsuba/__init__.py:319, in MitsubaModule.set_variant(self, *args)
    317     _reload(sys.modules['mitsuba.ad.integrators'])
    318 else:
--> 319     _import('mitsuba.ad.integrators')
    320 del sys

File ~/miniconda3/envs/mitsuba/lib/python3.8/importlib/__init__.py:127, in import_module(name, package)
    125             break
    126         level += 1
--> 127 return _bootstrap._gcd_import(name[level:], package, level)

File <frozen importlib._bootstrap>:1014, in _gcd_import(name, package, level)

File <frozen importlib._bootstrap>:991, in _find_and_load(name, import_)

File <frozen importlib._bootstrap>:961, in _find_and_load_unlocked(name, import_)

File <frozen importlib._bootstrap>:219, in _call_with_frames_removed(f, *args, **kwds)

File <frozen importlib._bootstrap>:1014, in _gcd_import(name, package, level)

File <frozen importlib._bootstrap>:991, in _find_and_load(name, import_)

File <frozen importlib._bootstrap>:975, in _find_and_load_unlocked(name, import_)

File <frozen importlib._bootstrap>:671, in _load_unlocked(spec)

File <frozen importlib._bootstrap_external>:843, in exec_module(self, module)

File <frozen importlib._bootstrap>:219, in _call_with_frames_removed(f, *args, **kwds)

File ~/eradiate/build/ext/mitsuba/python/mitsuba/python/ad/__init__.py:1, in <module>
----> 1 from .integrators import *
      2 from .optimizers import *
      3 from .reparam import *

File ~/eradiate/build/ext/mitsuba/python/mitsuba/python/ad/integrators/__init__.py:25, in <module>
     23         importlib.reload(globals()[name])
     24     else:
---> 25         importlib.import_module('mitsuba.ad.integrators.' + name)
     27     del name
     28 del f

File ~/miniconda3/envs/mitsuba/lib/python3.8/importlib/__init__.py:127, in import_module(name, package)
    125             break
    126         level += 1
--> 127 return _bootstrap._gcd_import(name[level:], package, level)

File ~/eradiate/build/ext/mitsuba/python/mitsuba/python/ad/integrators/prb.py:6, in <module>
      3 import drjit as dr
      4 import mitsuba as mi
----> 6 from .common import RBIntegrator, mis_weight
      8 class PRBIntegrator(RBIntegrator):
      9     r"""
     10     .. _integrator-prb:
     11 
   (...)
     56             'max_depth': 8
     57     """

File ~/eradiate/build/ext/mitsuba/python/mitsuba/python/ad/integrators/common.py:8, in <module>
      4 import drjit as dr
      5 import gc
----> 8 class ADIntegrator(mi.CppADIntegrator):
      9     """
     10     Abstract base class of numerous differentiable integrators in Mitsuba
     11 
   (...)
     25          visible surfaces. (Default: 5)
     26     """
     28     def __init__(self, props = mi.Properties()):

File ~/eradiate/build/ext/mitsuba/python/mitsuba/__init__.py:255, in MitsubaModule.__getattribute__(self, key)
    253     sub_suffix = '' if submodule is None else f'.{submodule}'
    254     module = sys.modules[f'mitsuba.{variant}{sub_suffix}']
--> 255     result = module.__getattribute__(key)
    257 # Add set_variant(), variant() and variant modules to the __dict__
    258 if submodule is None and key == '__dict__':

File ~/eradiate/build/ext/mitsuba/python/mitsuba/__init__.py:122, in MitsubaVariantModule.__getattribute__(self, key)
    120         raise AttributeError('Mitsuba variant "%s" not found.' % variant)
    121     else:
--> 122         raise AttributeError(e)
    123 finally:
    124     # Remove those modules from sys.modules as only the
    125     # MitsubaVariantModule instance should hold a reference to them.
    126     sys.modules.pop('mitsuba.mitsuba_ext', None)

AttributeError: jit_init_thread_state(): the LLVM backend is inactive because the LLVM shared library ("libLLVM.so") could not be found! Set the DRJIT_LIBLLVM_PATH environment variable to specify its path.

Steps to reproduce

1. install mitsuba using pip install mitsuba
2. usage "hello world" example

# Import the library using the alias "mi"
import mitsuba as mi
# Set the variant of the renderer
mi.set_variant('scalar_rgb')
# Load a scene
scene = mi.load_dict(mi.cornell_box())
# Render the scene
img = mi.render(scene)
# Write the rendered image to an EXR file
mi.Bitmap(img).write('cbox.exr')

3. usage another example

import mitsuba as mi
# Set the variant of the renderer
mi.set_variant('llvm_ad_rgb')

[merlinND]

Hello @gritk,

Does your system have a working installation of LLVM?

It looks like there's no libLLVM.so in the search path. Installing clang or llvm with apt should fix the issue.
You can also check if there's an existing installation using locate libLLVM.so.

[gritk]

Changing cpu solved the problem!

model name : Common KVM processor
changed to
model name : AMD EPYC 7401 24-Core Processor
(it was the default CPU for a VM, and it was changed to that of the host machine itself)

[njroussel]

Great, for posterity:

Here, the libLLVM.so could not be found error is a symptom of the earlier log jit_llvm_init(): no suitable vector ISA found, shutting down LLVM backend.. This is a sign that the CPU architecture is missing some required instruction sets my Mitsuba/Dr.Jit.

[bluestyle97]

Hi, I also meet this issue when installing mitsuba3 by pip install mitsuba on CentOS 7. I have built LLVM 12.0 from the source and have a libLLVM.so in /usr/local/lib and it's in my LD_LIBRARY_PATH variable. However, I keep getting the following error when running mi.set_variant('llvm_ad_rgb'):

jit_llvm_init(): could not hot-patch TargetMachine relocation model!
 - Warning: device does *not* support managed memory, skipping ..
Traceback (most recent call last):
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/__init__.py", line 127, in __getattribute__
    _import('mitsuba.mitsuba_' + variant + '_ext'),
  File "/root/anaconda3/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 666, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 565, in module_from_spec
  File "<frozen importlib._bootstrap_external>", line 1173, in create_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
ImportError: jit_init_thread_state(): the LLVM backend is inactive because the LLVM shared library ("libLLVM.so") could not be found! Set the DRJIT_LIBLLVM_PATH environment variable to specify its path.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/group/jialexu/projects/differentiable-sdf-rendering/python/optimize.py", line 109, in <module>
    main(sys.argv[1:])
  File "/group/jialexu/projects/differentiable-sdf-rendering/python/optimize.py", line 79, in main
    mi.set_variant('llvm_ad_rgb' if use_llvm else 'cuda_ad_rgb')
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/__init__.py", line 340, in set_variant
    _import('mitsuba.ad.integrators')
  File "/root/anaconda3/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 972, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 850, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/python/ad/__init__.py", line 1, in <module>
    from .integrators import *
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/python/ad/integrators/__init__.py", line 25, in <module>
    importlib.import_module('mitsuba.ad.integrators.' + name)
  File "/root/anaconda3/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/python/ad/integrators/prb_reparam.py", line 6, in <module>
    from .common import RBIntegrator, mis_weight
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/python/ad/integrators/common.py", line 8, in <module>
    class ADIntegrator(mi.CppADIntegrator):
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/__init__.py", line 276, in __getattribute__
    result = module.__getattribute__(key)
  File "/root/anaconda3/lib/python3.9/site-packages/mitsuba/__init__.py", line 138, in __getattribute__
    raise AttributeError(e)
AttributeError: jit_init_thread_state(): the LLVM backend is inactive because the LLVM shared library ("libLLVM.so") could not be found! Set the DRJIT_LIBLLVM_PATH environment variable to specify its path.

Then I set export DRJIT_LIBLLVM_PATH=/usr/local/lib/libLLVM.so, but it's no use. Do you have any suggestion?

[njroussel]

The error message is a bit misleading in your case @bluestyle97.
What's important in the log you posted is the following:

jit_llvm_init(): could not hot-patch TargetMachine relocation model!

In short, Mitsuba/Dr.Jit found the LLVM library, loaded it and then tried to run a few operations/checks with it to make sure everything is working as expected but failed during this step.

I remember trying Mitsuba on CentOS 7 and was encountering the same issue with certain versions of LLVM. Can you try using a pre-built package instead? You can user lower versions than LLVM 12.

[bluestyle97]

OK, I will try using a pre-build lower-version LLVM.

[arpit15]

I am facing similar issue on Mac M2. I have libLLVM.dylib.
I added following line to the top of my script.
os.environ['DRJIT_LIBLLVM_PATH'] = "/opt/homebrew/opt/llvm/lib/libLLVM.dylib"

Are there any suggestions for a workaround?

jit_llvm_init(): detected LLVM version lacks critical functionality, shutting down LLVM backend..
Traceback (most recent call last):
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/__init__.py", line 107, in __getattribute__
    _import('mitsuba.mitsuba_' + variant + '_ext'),
  File "/Users/virtualworld/.pyenv/versions/3.10.13/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 674, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 571, in module_from_spec
  File "<frozen importlib._bootstrap_external>", line 1176, in create_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
ImportError: jit_init_thread_state(): the LLVM backend is inactive because the LLVM shared library ("libLLVM.dylib") could not be found! Set the DRJIT_LIBLLVM_PATH environment variable to specify its path.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/virtualworld/projects/custom_mit_plugins/main.py", line 6, in <module>
    mi.set_variant("llvm_ad_rgb")
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/__init__.py", line 317, in set_variant
    _import('mitsuba.ad.integrators')
  File "/Users/virtualworld/.pyenv/versions/3.10.13/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 992, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/python/ad/__init__.py", line 1, in <module>
    from .integrators import *
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/python/ad/integrators/__init__.py", line 25, in <module>
    importlib.import_module('mitsuba.ad.integrators.' + name)
  File "/Users/virtualworld/.pyenv/versions/3.10.13/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/python/ad/integrators/prbvolpath.py", line 6, in <module>
    from .common import RBIntegrator, mis_weight
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/python/ad/integrators/common.py", line 8, in <module>
    class ADIntegrator(mi.CppADIntegrator):
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/__init__.py", line 253, in __getattribute__
    result = module.__getattribute__(key)
  File "/Users/virtualworld/.pyenv/versions/py3x13/lib/python3.10/site-packages/mitsuba/__init__.py", line 115, in __getattribute__
    raise AttributeError(e)
AttributeError: jit_init_thread_state(): the LLVM backend is inactive because the LLVM shared library ("libLLVM.dylib") could not be found! Set the DRJIT_LIBLLVM_PATH environment variable to specify its path.

[merlinND]

Hello @arpit15,

detected LLVM version lacks critical functionality, shutting down LLVM backend..

Some users have reported this error message when using LLVM 17. Downgrading to LLVM 16 typically solves the issue.

[njroussel]

I can confirm: LLVM 17 is currently incompatible with all drjit releases.

[wjakob]

Fixed mitsuba-renderer/drjit-core@b842286