[compiler-rt] b9935bb - asan_static x86-64: Support 64-bit ASAN_SHADOW_OFFSET_CONST (#75748)
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Mon Dec 18 13:48:51 PST 2023
Author: Fangrui Song
Date: 2023-12-18T13:48:46-08:00
New Revision: b9935bb02a506e9142ae79b6c58303cb2e1ffb08
URL: https://github.com/llvm/llvm-project/commit/b9935bb02a506e9142ae79b6c58303cb2e1ffb08
DIFF: https://github.com/llvm/llvm-project/commit/b9935bb02a506e9142ae79b6c58303cb2e1ffb08.diff
LOG: 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`.
Added:
Modified:
compiler-rt/lib/asan/asan_rtl_x86_64.S
Removed:
################################################################################
diff --git a/compiler-rt/lib/asan/asan_rtl_x86_64.S b/compiler-rt/lib/asan/asan_rtl_x86_64.S
index 0b7363018f425f..e44587ac4331c7 100644
--- a/compiler-rt/lib/asan/asan_rtl_x86_64.S
+++ b/compiler-rt/lib/asan/asan_rtl_x86_64.S
@@ -27,7 +27,12 @@ FNAME(reg, op, s, i): ;\
#define ASAN_MEMORY_ACCESS_INITIAL_CHECK_ADD(reg, op, s) \
mov %##reg,%r10 ;\
shr $0x3,%r10 ;\
+ .if ASAN_SHADOW_OFFSET_CONST < 0x80000000 ;\
movsbl ASAN_SHADOW_OFFSET_CONST(%r10),%r10d ;\
+ .else ;\
+ movabsq $ASAN_SHADOW_OFFSET_CONST,%r11 ;\
+ movsbl (%r10,%r11),%r10d ;\
+ .endif ;\
test %r10d,%r10d ;\
jne CLABEL(reg, op, s, add) ;\
RLABEL(reg, op, s, add): ;\
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