Update mimalloc to v2.1.2 #4740
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Revert this in preparation for upgrading mimalloc to v2.1.2 and then redoing this patch. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Revert this in preparation for upgrading mimalloc to v2.1.2 and then redoing this patch. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Revert this in preparation for upgrading mimalloc to v2.1.2 and then redoing this patch. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
In preparation for upgrading mimalloc to v2.1.2, let's revert this patch so that we can start afresh, from a clean slate. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Import the source code of mimalloc v2.1.2 This commit imports mimalloc's source code as per v2.1.2, fetched from the tag at https://github.com/microsoft/mimalloc. The .c files are from the src/ subdirectory, and the .h files from the include/ and include/mimalloc/ subdirectories. We will subsequently modify the source code to accommodate building within Git's context. Since we plan on using the `mi_*()` family of functions, we skip the C++-specific source code, some POSIX compliant functions to interact with mimalloc, and the code that wants to support auto-magic overriding of the `malloc()` function (mimalloc-new-delete.h, alloc-posix.c, mimalloc-override.h, alloc-override.c, alloc-override-osx.c, alloc-override-win.c and static.c). To appease the `check-whitespace` job of Git's Continuous Integration, this commit was washed one time via `git rebase --whitespace=fix`. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
We want to compile mimalloc's source code as part of Git, rather than requiring the code to be built as an external library: mimalloc uses a CMake-based build, which is not necessarily easy to integrate into the flavors of Git for Windows (which will be the main benefitting port). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
By defining `USE_MIMALLOC`, Git can now be compiled with that nicely-fast and small allocator. Note that we have to disable a couple `DEVELOPER` options to build mimalloc's source code, as it makes heavy use of declarations after statements, among other things that disagree with Git's conventions. We even have to silence some GCC warnings in non-DEVELOPER mode. For example, the `-Wno-array-bounds` flag is needed because in `-O2` builds, trying to call `NtCurrentTeb()` (which `_mi_thread_id()` does on Windows) causes the bogus warning about a system header, likely related to https://sourceforge.net/p/mingw-w64/mailman/message/37674519/ and to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578: C:/git-sdk-64-minimal/mingw64/include/psdk_inc/intrin-impl.h:838:1: error: array subscript 0 is outside array bounds of 'long long unsigned int[0]' [-Werror=array-bounds] 838 | __buildreadseg(__readgsqword, unsigned __int64, "gs", "q") | ^~~~~~~~~~~~~~ Also: The `mimalloc` library uses C11-style atomics, therefore we must require that standard when compiling with GCC if we want to use `mimalloc` (instead of requiring "only" C99). This is what we do in the CMake definition already, therefore this commit does not need to touch `contrib/buildsystems/`. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Always use the internal "use_weak" random seed when initializing the "mimalloc" heap when statically linked on Windows. The imported "mimalloc" routines support several random sources to seed the heap data structures, including BCrypt.dll and RtlGenRandom. Crashes have been reported when using BCrypt.dll if it initialized during an `atexit()` handler function. Granted, such DLL initialization should not happen in an atexit handler, but yet the crashes remain. It should be noted that on Windows when statically linked, the mimalloc startup code (called by the GCC CRT to initialize static data prior to calling `main()`) always uses the internal "weak" random seed. "mimalloc" does not try to load an alternate random source until after the OS initialization has completed. Heap data is stored in `__declspec(thread)` TLS data and in theory each Git thread will have its own heap data. However, testing shows that the "mimalloc" library doesn't actually call `os_random_buf()` (to load a new random source) when creating these new per-thread heap structures. However, if an atexit handler is forced to run on a non-main thread, the "mimalloc" library *WILL* try to create a new heap and seed it with `os_random_buf()`. (The reason for this is still a mystery to this author.) The `os_random_buf()` call can cause the (previously uninitialized BCrypt.dll library) to be dynamically loaded and a call made into it. Crashes have been reported in v2.40.1.vfs.0.0 while in this call. As a workaround, the fix here forces the use of the internal "use_weak" random code for the subsequent `os_random_buf()` calls. Since we have been using that random generator for the majority of the program, it seems safe to use it for the final few mallocs in the atexit handler (of which there really shouldn't be that many. Signed-off-by: Jeff Hostetler <jeffhostetler@github.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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The mimalloc project has released a couple versions since we last integrated it into Git for Windows. Let's take the most recent one.
This PR is structured in the following way:
fixup!s of the reverted commits.amend!of the commit that originally imported mimalloc.fixup!s of the original commits.