Refactor CMake buildsystem to be portable and modern #304
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Aggreggate source files directly in the target instead of a proxy variable. Install CMake package config files in order to allow the project to be found via `find_package()` by dependents. Replace hard coded SIMD compiler flags with configurable options. Retain the current GCC/Clang flags as defaults for these compilers. Add default SIMD compiler flags for MSVC. Remove hard coded compiler flags (including -fPIC). These are not portable and should be set by the toolchain file or on the CLI. - Guard ASM sources with triplet compatibility checks. - Remove the `BLAKE3_STATIC` option in favor of [`BUILD_SHARED_LIBS`]. [`BUILD_SHARED_LIBS`]: https://cmake.org/cmake/help/v3.9/variable/BUILD_SHARED_LIBS.html
In order for blake3 to be usable as a shared library on Windows it is required to annotate public symbols. Use this as an opportunity to prune the symbol table for other OSes, too.
Co-authored-by: Henrik Gaßmann <BurningEnlightenment@users.noreply.github.com>
Co-authored-by: Henrik Gaßmann <BurningEnlightenment@users.noreply.github.com>
| size_t out_len); | ||
| BLAKE3_API void blake3_hasher_finalize_seek(const blake3_hasher *self, uint64_t seek, | ||
| uint8_t *out, size_t out_len); | ||
| BLAKE3_API void blake3_hasher_reset(blake3_hasher *self); |
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Could you say more about what these macros are doing? I'm a little nervous about leaking complexity into the header files that might affect folks who aren't using CMake to build this.
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These macros control which symbols (=> C functions / global variables) end up in the shared object's (.so) symbol table, i.e. what you can access via dlsym(). The default on gcc and clang is to export all entities with external linkage while Windows / MSVC defaults to exporting only entities annotated with __declspec(dllexport). Without these annotations you basically can't use the blake3.dll. So these aren't actually CMake specific; they are useful regardless of the buildsystem. You can see a similar macro used by libb2 here:
https://github.com/BLAKE2/libb2/blame/6fafe5c546860ecbdd2b97093a93ae4ce54dfe52/src/blake2.h#L20-L44
You can read more about symbol visibility on the GCC Wiki and the MSVC docs.
Also note that I configured CMake to set the default visibility to hidden for GCC / clang.
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Thanks for putting this together! I'm going to learn a lot reading through it :) |
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@oconnor663 do you have further questions or can we get this merged? |
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Merged! Thank you! I'll admit I still have no idea what I'm doing, and I only kicked the tires a little bit, but it makes me really happy that this works: I guess the next question is how we should document this? :) |
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I can write a section for the On a related note I'm going to update the vcpkg port based on this; maybe someone else does the work for conan. |
This is building on top of @SteveGremory's #247
Resolves #102
Aggreggate source files directly in the target instead of a proxy variable.
Install CMake package config files in order to allow the project to be found via
find_package()by dependents.Remove hard coded compiler flags (including -fPIC). These are not portable and should be set by the toolchain file or on the CLI.
Replace hard coded SIMD compiler flags with configurable options. Retain the current GCC/Clang flags as defaults for these compilers. Add default SIMD compiler flags for MSVC.
Guard ASM sources with triplet compatibility checks.
Remove the
BLAKE3_STATICoption in favor ofBUILD_SHARED_LIBS.