asan_static x86-64: Support 64-bit ASAN_SHADOW_OFFSET_CONST (#75748)
Fix #57086: when ASAN_SHADOW_OFFSET_CONST >= 0x80000000 (FreeBSD,
NetBSD, etc), `movsbl ASAN_SHADOW_OFFSET_CONST(%r10),%r10d` has an
invalid displacement (not representable as a signed 32-bit integer),
which will be diagnosed by GNU assembler.
```
% cat a.s
movsbl 0x80000000(%r10),%r10d
% as a.s
a.s: Assembler messages:
a.s:1: Error: 0x80000000 out of range of signed 32bit displacement
% clang -c a.s
```
The integrated assembler after #75747 will diagnose the invalid
displacement as well.
```
% clang -c a.s
a.s:1:19: error: displacement 2147483648 is not within [-2147483648, 2147483647]
movsbl 0x80000000(%r10),%r10d
^
```
If ASAN_SHADOW_OFFSET_CONST cannot be encoded as a displacement, switch
to `movabsq+movsbl`.
parent
5ccad1b9