[arm64] Fix pre-shifted immediate generation involving csp.

src/arm64/macro-assembler-arm64.h

Index: src/arm64/macro-assembler-arm64.h
diff --git a/src/arm64/macro-assembler-arm64.h b/src/arm64/macro-assembler-arm64.h
index bc2d9b39ac056e2333d8c32631e1bdc70ab154f2..6444530ebbf1b17d5f13ce59394d59d7c97d4130 100644
--- a/src/arm64/macro-assembler-arm64.h
+++ b/src/arm64/macro-assembler-arm64.h
@@ -162,6 +162,21 @@ enum CopyHint { kCopyUnknown, kCopyShort, kCopyLong };
 enum DiscardMoveMode { kDontDiscardForSameWReg, kDiscardForSameWReg };
 enum SeqStringSetCharCheckIndexType { kIndexIsSmi, kIndexIsInteger32 };
 
+// The macro assembler supports moving automatically pre-shifted immediates for
+// arithmetic and logical instructions, and then applying a post shift in the
+// instruction to undo the modification, in order to reduce the code emitted for
+// an operation. For example:
+//
+//  Add(x0, x0, 0x1f7de) => movz x16, 0xfbef; add x0, x0, x16, lsl #1.
+//
+// This optimisation can be only partially applied when the stack pointer is an
+// operand or destination, so this enumeration is used to control the shift.
+enum PreShiftImmMode {
+  kNoShift,          // Don't pre-shift.
+  kLimitShiftForSP,  // Limit pre-shift for add/sub extend use.
+  kAnyShift          // Allow any pre-shift.
+};
+
 class MacroAssembler : public Assembler {
  public:
   MacroAssembler(Isolate* isolate, byte* buffer, unsigned buffer_size,
@@ -276,7 +291,8 @@ class MacroAssembler : public Assembler {
   // dst is not necessarily equal to imm; it may have had a shifting operation
   // applied to it that will be subsequently undone by the shift applied in the
   // Operand.
-  Operand MoveImmediateForShiftedOp(const Register& dst, int64_t imm);
+  Operand MoveImmediateForShiftedOp(const Register& dst, int64_t imm,
+                                    PreShiftImmMode mode);
 
   // Conditional macros.
   inline void Ccmp(const Register& rn,