Imagemagick: OpenCL Detection is still broken on macOS it seems

[Naville]

Prerequisites

• [x] I have written a descriptive issue title
• [x] I have verified that I am using the latest version of ImageMagick
• [x] I have searched open and closed issues to ensure it has not already been reported

Description

./configure won't detect presence of OpenCL on macOS

Steps to Reproduce

./configure
The output log has the following related part:
configure:11271: checking for OpenCL library configure:11314: gcc -o conftest -g -O2 -Wall -mtune=core2 -fexceptions -D_FORTIFY_SOURCE=0 -pthread -pthread conftest.c -lOpenCL -lm >&5 conftest.c:50:1: warning: 'clCreateContextFromType' is deprecated: first deprecated in macOS 10.14 - (Define CL_SILENCE_DEPRECATION to hide this warning) [-Wdeprecated-declarations] clCreateContextFromType(0,0,0,0,0) ^ /System/Library/Frameworks/OpenCL.framework/Headers/cl.h:620:1: note: 'clCreateContextFromType' has been explicitly marked deprecated here clCreateContextFromType(const cl_context_properties * /* properties */, ^ 1 warning generated. ld: library not found for -lOpenCL clang: error: linker command failed with exit code 1 (use -v to see invocation)

OpenCL headers are properly detected though

System Configuration

• ImageMagick version: 206bac54bac9e106b281ba3f28355d0e8d5c376b
• Environment (Operating system, version and so on): macOS 10.14.2
• Additional information: N/A

[Naville]

@dlemstra Since you edited this issue I assume I should probably ping you on this one. The current bypass used by ImageMagick works perfectly fine on the -framework OpenCL part, however seems like the full command still contains elements from other configurations like -lOpenCL and -lCL which were the actual reason of the failure. It seems if we modify the m4 to only uses -framework OpenCL without other CL linker flags would solve this issue. However autoconf grammar is just too much for me

[Naville]

configure:11364: gcc -o conftest  -g -O2 -Wall -mtune=core2 -fexceptions -D_FORTIFY_SOURCE=0 -pthread -pthread   conftest.c -lOpenCL -framework OpenCL -L/System/Library/Frameworks/OpenCL.framework/Versions/A/Libraries  -lm   >&5
conftest.c:50:1: warning: 'clCreateContextFromType' is deprecated: first deprecated in macOS 10.14 - (Define CL_SILENCE_DEPRECATION to hide this warning) [-Wdeprecated-declarations]
clCreateContextFromType(0,0,0,0,0)
^
/System/Library/Frameworks/OpenCL.framework/Headers/cl.h:620:1: note: 'clCreateContextFromType' has been explicitly marked deprecated here
clCreateContextFromType(const cl_context_properties * /* properties */,
^
1 warning generated.
ld: library not found for -lOpenCL
clang: error: linker command failed with exit code 1 (use -v to see invocation)**

Yeah it shouldn't have -lOpenCL or -L/System/Library/Frameworks/OpenCL.framework/Versions/A/Libraries. -framework OpenCL should be all we need

[dlemstra]

These settings are defined in the m4/ax_opencl.m4 file. Can you tell us how we should patch this file to make it work on macOS @Naville?

[Naville]

I dunno sh1t aboutM4 Grammar. But as mentioned in the original issue, resulting linker command should only have -framework OpenCL present

[urban-warrior]

Thanks for the problem report. We can reproduce it and will have a patch to fix it in the GIT master branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ https://www.imagemagick.org/download/beta/ by sometime tomorrow.