Daniel Borkmann 6fe8b9c1f4 bpf, x64: save several bytes by using mov over movabsq when possible ... While analyzing some of the more complex BPF programs from Cilium, I found that LLVM generally prefers to emit LD_IMM64 instead of MOV32 BPF instructions for loading unsigned 32-bit immediates into a register. Given we cannot change the current/stable LLVM versions that are already out there, lets optimize this case such that the JIT prefers to emit 'mov %eax, imm32' over 'movabsq %rax, imm64' whenever suitable in order to reduce the image size by 4-5 bytes per such load in the typical case, reducing image size on some of the bigger programs by up to 4%. emit_mov_imm32() and emit_mov_imm64() have been added as helpers. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>		2018-02-23 22:50:00 -08:00
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bpf_jit.S	bpf: change x86 JITed program stack layout	2017-05-31 19:29:48 -04:00
bpf_jit_comp.c	bpf, x64: save several bytes by using mov over movabsq when possible	2018-02-23 22:50:00 -08:00
Makefile	objtool, x86: Add several functions and files to the objtool whitelist	2017-06-30 10:19:19 +02:00