ARM64: Fix GC encoding settings

This change fixes certain settings in the GCInfo encoder/decoders.
It also fixes the debug info for the stack pointer.

src/gcinfo/gcinfoencoder.cpp

@@ -1079,6 +1079,7 @@ void GcInfoEncoder::Build()
     }
 
     _ASSERTE( m_CodeLength > 0 );
+    _ASSERTE(DENORMALIZE_CODE_LENGTH(NORMALIZE_CODE_LENGTH(m_CodeLength)) == m_CodeLength);
     GCINFO_WRITE_VARL_U(m_Info1, NORMALIZE_CODE_LENGTH(m_CodeLength), CODE_LENGTH_ENCBASE, CodeLengthSize);
 
     if(hasGSCookie)
@@ -1216,6 +1217,7 @@ void GcInfoEncoder::Build()
         // (after, of course, adding the size of the call instruction to get the return PC).
         callSite += m_pCallSiteSizes[callSiteIndex] - 1;
 
+        _ASSERTE(DENORMALIZE_CODE_OFFSET(NORMALIZE_CODE_OFFSET(callSite)) == callSite);
         UINT32 normOffset = NORMALIZE_CODE_OFFSET(callSite);
 
         BOOL keepIt = TRUE;
@@ -2032,7 +2034,7 @@ void GcInfoEncoder::Build()
 
         if(!IsEssential(pClause))
             continue;
-        
+
         UINT32 normStartOffset = NORMALIZE_CODE_OFFSET(pClause->TryStartPC);
         UINT32 normStopOffset = NORMALIZE_CODE_OFFSET(pClause->TryEndPC);
         _ASSERTE(normStopOffset > normStartOffset);        

src/inc/gcinfotypes.h

@@ -255,24 +255,22 @@ struct GcStackSlot
 
 #elif defined(_TARGET_ARM64_)
 
-// ARM64TODO: these were copied from AMD64, and need to be reviewed
-
 #ifndef TARGET_POINTER_SIZE
 #define TARGET_POINTER_SIZE 8    // equal to sizeof(void*) and the managed pointer size in bytes for this target
 #endif
 #define NUM_NORM_CODE_OFFSETS_PER_CHUNK (64)
 #define NUM_NORM_CODE_OFFSETS_PER_CHUNK_LOG2 (6)
-#define NORMALIZE_STACK_SLOT(x) ((x)>>3)
+#define NORMALIZE_STACK_SLOT(x) ((x)>>3)   // GC Pointers are 8-bytes aligned
 #define DENORMALIZE_STACK_SLOT(x) ((x)<<3)
-#define NORMALIZE_CODE_LENGTH(x) (x)
-#define DENORMALIZE_CODE_LENGTH(x) (x)
-#define NORMALIZE_STACK_BASE_REGISTER(x) ((x) ^ 5)
-#define DENORMALIZE_STACK_BASE_REGISTER(x) ((x) ^ 5)
+#define NORMALIZE_CODE_LENGTH(x) ((x)>>2)   // All Instructions are 4 bytes long
+#define DENORMALIZE_CODE_LENGTH(x) ((x)<<2) 
+#define NORMALIZE_STACK_BASE_REGISTER(x) ((x)^29) // Encode Frame pointer X29 as zero
+#define DENORMALIZE_STACK_BASE_REGISTER(x) ((x)^29)
 #define NORMALIZE_SIZE_OF_STACK_AREA(x) ((x)>>3)
 #define DENORMALIZE_SIZE_OF_STACK_AREA(x) ((x)<<3)
 #define CODE_OFFSETS_NEED_NORMALIZATION 0
-#define NORMALIZE_CODE_OFFSET(x) (x)
-#define DENORMALIZE_CODE_OFFSET(x) (x)
+#define NORMALIZE_CODE_OFFSET(x) (x)   // Instructions are 4 bytes long, but the safe-point
+#define DENORMALIZE_CODE_OFFSET(x) (x) // offsets are encoded with a -1 adjustment.
 #define NORMALIZE_REGISTER(x) (x)
 #define DENORMALIZE_REGISTER(x) (x)
 #define NORMALIZE_NUM_SAFE_POINTS(x) (x)
@@ -285,10 +283,10 @@ struct GcStackSlot
 #define SECURITY_OBJECT_STACK_SLOT_ENCBASE 6
 #define GS_COOKIE_STACK_SLOT_ENCBASE 6
 #define CODE_LENGTH_ENCBASE 8
-#define STACK_BASE_REGISTER_ENCBASE 3
+#define STACK_BASE_REGISTER_ENCBASE 2 // FP encoded as 0, SP as 2.
 #define SIZE_OF_STACK_AREA_ENCBASE 3
 #define SIZE_OF_EDIT_AND_CONTINUE_PRESERVED_AREA_ENCBASE 4
-#define NUM_REGISTERS_ENCBASE 2
+#define NUM_REGISTERS_ENCBASE 3
 #define NUM_STACK_SLOTS_ENCBASE 2
 #define NUM_UNTRACKED_SLOTS_ENCBASE 1
 #define NORM_PROLOG_SIZE_ENCBASE 5
@@ -300,7 +298,7 @@ struct GcStackSlot
 #define REGISTER_DELTA_ENCBASE 2
 #define STACK_SLOT_ENCBASE 6
 #define STACK_SLOT_DELTA_ENCBASE 4
-#define NUM_SAFE_POINTS_ENCBASE 2
+#define NUM_SAFE_POINTS_ENCBASE 3
 #define NUM_INTERRUPTIBLE_RANGES_ENCBASE 1
 #define NUM_EH_CLAUSES_ENCBASE 2
 #define POINTER_SIZE_ENCBASE 3

src/vm/gcinfodecoder.cpp

@@ -1904,8 +1904,7 @@ int GcInfoDecoder::GetStackReg(int spBase)
 #elif defined(_TARGET_ARM_)
     int esp = 13;
 #elif defined(_TARGET_ARM64_)
-    _ASSERTE("ARM64:NYI");
-    int esp = 30;
+    int esp = 31;
 #endif
 
     if( GC_SP_REL == spBase )