[sanitizer] Be more accurate when calculating the previous instruction address on ARM.
@@ -75,10 +75,11 @@ struct StackTrace {
ALWAYS_INLINE
uptr StackTrace::GetPreviousInstructionPc(uptr pc) {
#if defined(__arm__)
- // Cancel Thumb bit.
- pc = pc & (~1);
-#endif
-#if defined(__powerpc__) || defined(__powerpc64__)
+ // T32 (Thumb) branch instructions can be 16 or 32 bit long,
+ // so we return (pc-2) in that case in order to be safe.
+ // For A32 mode we return (pc-4) because all instructions are 32 bit long.
+ return (pc - 3) & (~1);
+#elif defined(__powerpc__) || defined(__powerpc64__) || defined(__aarch64__)
// PCs are always 4 byte aligned.
return pc - 4;
#elif defined(__sparc__) || defined(__mips__)
