Fix ARM/ARM64 hijacking in tail calls (#16039)

* Fix ARM/ARM64 hijacking in tail calls

This change fixes an issue that can happen when a function that has tail
calls is hijacked. There are two potential issues:

1. When a function that tail calls another one is hijacked, the LR may be
stored at a different location in the stack frame of the tail call
target.
So just by performing tail call, the hijacked location becomes invalid and
unhijacking would corrupt stack by writing to that location.

2. There is a small window after the caller pops LR from the stack in its
epilog and before the tail called function pushes LR in its prolog when
the hijacked return address would not be not on the stack and so we would
not be able to unhijack.

The fix is to prevent hijacking of functions that contain tail calls.

* Enable the tailcall hijacking test for ARM64

The test JIT/Methodical/tailcall_v4/hijacking should be passing now on
ARM64.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/gcdump/gcdumpnonx86.cpp b/src/gcdump/gcdumpnonx86.cpp
index ca8cc75792..7a7ebfe36b 100644
--- a/src/gcdump/gcdumpnonx86.cpp
+++ b/src/gcdump/gcdumpnonx86.cpp
@@ -433,8 +433,11 @@ size_t      GCDump::DumpGCTable(PTR_CBYTE      gcInfoBlock,
                                     ? "<none>"
                                     : GetRegName(hdrdecoder.GetStackBaseRegister()));
 
+#ifdef _TARGET_AMD64_
     gcPrintf("Wants Report Only Leaf: %u\n", hdrdecoder.WantsReportOnlyLeaf());
-    
+#elif defined(_TARGET_ARM_) || defined(_TARGET_ARM64_)
+    gcPrintf("Has tailcalls: %u\n", hdrdecoder.HasTailCalls());
+#endif // _TARGET_AMD64_
 #ifdef FIXED_STACK_PARAMETER_SCRATCH_AREA
     gcPrintf("Size of parameter area: %x\n", hdrdecoder.GetSizeOfStackParameterArea());
 #endif