Yonghong Song 286daafd65 [BPF] support atomic instructions ... Implement fetch_<op>/fetch_and_<op>/exchange/compare-and-exchange instructions for BPF. Specially, the following gcc intrinsics are implemented. __sync_fetch_and_add (32, 64) __sync_fetch_and_sub (32, 64) __sync_fetch_and_and (32, 64) __sync_fetch_and_or (32, 64) __sync_fetch_and_xor (32, 64) __sync_lock_test_and_set (32, 64) __sync_val_compare_and_swap (32, 64) For __sync_fetch_and_sub, internally, it is implemented as a negation followed by __sync_fetch_and_add. For __sync_lock_test_and_set, despite its name, it actually does an atomic exchange and return the old content. https://gcc.gnu.org/onlinedocs/gcc-4.1.1/gcc/Atomic-Builtins.html For intrinsics like __sync_{add,sub}_and_fetch and __sync_bool_compare_and_swap, the compiler is able to generate codes using __sync_fetch_and_{add,sub} and __sync_val_compare_and_swap. Similar to xadd, atomic xadd, xor and xxor (atomic_<op>) instructions are added for atomic operations which do not have return values. LLVM will check the return value for __sync_fetch_and_{add,and,or,xor}. If the return value is used, instructions atomic_fetch_<op> will be used. Otherwise, atomic_<op> instructions will be used. All new instructions only support 64bit and 32bit with alu32 mode. old xadd instruction still supports 32bit without alu32 mode. For encoding, please take a look at test atomics_2.ll. Differential Revision: https://reviews.llvm.org/D72184		2020-12-03 07:38:00 -08:00
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BPFDisassembler.cpp	[BPF] support atomic instructions	2020-12-03 07:38:00 -08:00
CMakeLists.txt	llvmbuildectomy - replace llvm-build by plain cmake	2020-11-13 10:35:24 +01:00