main里啥代码也没

happy@ubuntu:~$ $CXX -static -O0 -std=c++2a 1.cpp
happy@ubuntu:~$ gdb -batch -ex 'file a.out' -ex 'disassemble main'
Dump of assembler code for function main:
   0x000000000040226d <+0>:    push   %rbp
   0x000000000040226e <+1>:    mov    %rsp,%rbp
   0x0000000000402271 <+4>:    mov    $0x0,%eax
   0x0000000000402276 <+9>:    pop    %rbp
   0x0000000000402277 <+10>:    ret    
End of assembler dump.
happy@ubuntu:~$ $CXX -v
Using built-in specs.
COLLECT_GCC=/opt/cross/bin/x86_64-linux-musl-g++
COLLECT_LTO_WRAPPER=/opt/cross/bin/../libexec/gcc/x86_64-linux-musl/12.2.0/lto-wrapper
Target: x86_64-linux-musl
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