arm64singlestepper (#25512)

Add single step emulation for arm64 Linux

Add a copy and rework armsinglestepper to arm64singlestepper

Add arm64 emulation of all armv8 user space instructions which read or write PC.
- ADR, ADRP
- Branch instructions: B, BL, B.cond, BR, BLR, RET
- LDR (literal)

* Add FEATURE_EMULATE_SINGLESTEP 
* Enable for ARM64 linux

* Debugging fixes

Fix IsSSFlagEnabled bug
Fix opcode type
Fix code buffer asserts
Fix CBZ typo
Fix BitExtract
Fix m_targetPc
Minimize written instructions
Fix comments
Fix Bypass address truncation
Fix false assert
Add additional logging
Use %lx to log addresses
Remove stray LOG
Remove stray assert

1 files changed, 5 insertions, 5 deletions

diff --git a/src/vm/exceptionhandling.cpp b/src/vm/exceptionhandling.cpp
index 87220c345f..4de884fb74 100644
--- a/src/vm/exceptionhandling.cpp
+++ b/src/vm/exceptionhandling.cpp
@@ -5190,8 +5190,8 @@ BOOL IsSafeToHandleHardwareException(PCONTEXT contextRecord, PEXCEPTION_RECORD e
         IsIPInMarkedJitHelper(controlPc));
 }
 
-#ifdef _TARGET_ARM_
-static inline BOOL HandleArmSingleStep(PCONTEXT pContext, PEXCEPTION_RECORD pExceptionRecord, Thread *pThread)
+#ifdef FEATURE_EMULATE_SINGLESTEP
+static inline BOOL HandleSingleStep(PCONTEXT pContext, PEXCEPTION_RECORD pExceptionRecord, Thread *pThread)
 {
     // On ARM we don't have any reliable hardware support for single stepping so it is emulated in software.
     // The implementation will end up throwing an EXCEPTION_BREAKPOINT rather than an EXCEPTION_SINGLE_STEP
@@ -5211,7 +5211,7 @@ static inline BOOL HandleArmSingleStep(PCONTEXT pContext, PEXCEPTION_RECORD pExc
     }
     return FALSE;
 }
-#endif // _TARGET_ARM_
+#endif // FEATURE_EMULATE_SINGLESTEP
 
 BOOL HandleHardwareException(PAL_SEHException* ex)
 {
@@ -5288,8 +5288,8 @@ BOOL HandleHardwareException(PAL_SEHException* ex)
             }
 #endif
 
-#ifdef _TARGET_ARM_
-            HandleArmSingleStep(ex->GetContextRecord(), ex->GetExceptionRecord(), pThread);
+#ifdef FEATURE_EMULATE_SINGLESTEP
+            HandleSingleStep(ex->GetContextRecord(), ex->GetExceptionRecord(), pThread);
 #endif
             if (ex->GetExceptionRecord()->ExceptionCode == STATUS_BREAKPOINT)
             {